JPS61186974A - Developing device - Google Patents

Abstract

PURPOSE:To make a titled device small in size by placing a hollow magnet in a cylindrical sleeve to which a one component insulating toner adheres, and placing a toner stirring tank which has been shielded magnetically, in the hollow magnet so as to be rotatable. CONSTITUTION:A toner stirring tank 24 is attached to a sleeve 22, and therefore, starts to rotate at the same rotating speed as the sleeve 22, and a toner 21 is stirred, contacts to the inside wall of the tank 24 many times, brought to a frictional electrification and spreads gradually to an exhaust port 27 side, collected in a toner reservoir 28 through the exhaust port 27, and spreads along the axial direction of the sleeve 22. Thereafter, it is absorbed by a magnet 23 and adheres to the sleeve 22, and while it moves in the direction as indicated with an arrow 29 by a rotation, it is checked by a toner control brade 30, spreads suddently in the axial direction of the sleeve 22, passes through the toner control brade 30 and carried to developing areas 32, 33, adsorbed to an electrostatic latent image, and a development is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a developing device using a one-component insulating magnetic toner.

BACKGROUND OF THE INVENTION FIG. 6 is a side sectional view of an example of a conventional developing device using one-component toner.

This developing device includes a cylindrical sleeve 2 that holds -component toner 1 and conveys the toner 1 by rotation, and a sleeve 2 that is arranged concentrically inside this sleeve 2 and that sucks the toner 1 onto the sleeve 2. It includes a magnet 3 and a toner receiver 4 which is provided at the lower part of the sleeve 2 and stores the toner 1.

In this developing device, as the sleeve 2 rotates, the toner 1 in the toner receiver 4 is held by the sleeve 2 and conveyed in the direction of arrow 6. When the toner 1 reaches the friction member 6, the toner 1 is rubbed by the friction member 6 and charged.

Then, the toner 1 has a uniform layer thickness by the blade 7, and in the developing section 8, the toner 1 adheres to the electrostatic latent image formed on the latent image carrier 9, such as a photoreceptor drum, and development is performed. It will be done. Thereafter, the toner 1 remaining on the step 17-2 is returned to the toner receiver 4.

Problems to be Solved by the Invention However, such a developing device requires a member or device that rubs the toner, and in order to perform stable frictional charging, the member or device inevitably becomes large. One of the advantages of using component toners, the miniaturization of the development device, is sacrificed.

The present invention solves the above-mentioned problems, and aims to provide a developing device that can stably charge toner and can be downsized.

Means for Solving the Problems The developing device of the present invention includes: - A hollow magnet is disposed within a cylindrical sleeve to which an insulating toner is attached, and a toner magnetically shielded within the hollow magnet. A stirring tank is rotatably arranged.

When toner is injected into the tank and the tank is rotated, the toner becomes electrically charged due to the friction between the toner and the tank. Then, the charged toner adheres to the sleeve via the toner receiver and is conveyed to the developing section. Toner adheres to an electrostatic latent image formed on a photoreceptor drum or the like installed in this developing section, and development is performed.

Example A developing device according to a first embodiment of the present invention is shown in FIG.

This developing device includes a cylindrical sleeve 2 that holds -component insulating magnetic toner 21 and moves the toner 21 by rotation.
2, arranged concentrically inside this sleeve 22,
A hollow magnet 23 for attracting and holding the toner 21 on the sleeve 22; and a toner agitation tank 24 rotatably disposed inside the hollow part of the magnet 23 and made of a ferromagnetic material and magnetically shielded. It is equipped with

Bearings 25 are provided at both ends of the magnet 23 relative to the sleeve 22 and tank 24, and the magnet 23 is rotatable relative to the sleeve 22 and tank 24.

Both ends of the agitation tank 24 are exposed outside the sleeve 22, one end is provided with a toner inlet 26 via a bearing 25a, and the other end is fixed to the sleeve 22. At the same time, a plurality of openings are formed in the circumferential direction to form toner discharge ports 27 .

A toner receiver 28 for temporarily storing toner is provided below the sleeve 22 and the toner stirring tank 24.

Next, the operation will be explained.

First, the toner 21 is put into the toner agitation tank 24 from the toner injection port 26. Since this tank 24 is attached to the sleeve 22, it starts rotating at the same rotational speed as the sleeve 22. As a result, the toner 21 in the tank 24 is agitated, comes into contact with the inner wall of the tank 24 many times, and gradually spreads toward the discharge 027 side while being frictionally charged. Then, the toner 2 that is different from the toner outlet 27 is
1 passes through the discharge port 27 and accumulates in the toner receiver 2, and gradually spreads along the axial direction of the sleeve 22. Then, it is attracted by the magnet 23 and attached to the sleeve 22 . As shown in FIG. 2, the toner 21 adhering to the sleeve 22 moves in the direction of arrow 29 due to the rotation of the sleeve 22 and magnet 23, while the toner regulating blade 3
0, and rapidly expands in the axial direction of the sleeve 22. The toner 21 that has passed through the toner regulating blade 30 is transported to the developing area 32 or 33 and is attracted to an electrostatic latent image formed on a photosensitive drum (not shown) provided facing the developing area 32 or 33. Development is performed.

Note that the magnetic force of the magnet 23 is applied to the toner stirring tank 24.
If the toner 21 reaches the inside of the tank 24, its magnetic force will attract the toner 21 to the inner wall of the tank 24, causing insufficient agitation and making it difficult for the toner 21 to reach the discharge port 27. Therefore, the tank 24 is made of ferromagnetic material. form the tank 24
Although the influence of the magnetic force inward is weakened, this may be countered by providing a member made of ferromagnetic material between the magnet 23 and the tank 240.

Note that the toner 21 can be charged more effectively by, for example, rotating the toner agitation tank 24 at high speed, or selecting the material used for the inner wall of the tank 24 in consideration of the frictional charging series with the toner 21. be able to.

Next, a second embodiment of the present invention will be described.

In this second embodiment, as shown in FIG.
22 is a bearing 12 relative to the toner stirring tank 24.
5. The sleeve 122 extends outside the sleeve 122 on the side of the toner discharge port 27 of the tank 24 .

A side wall of the toner receiver 128 at a portion corresponding to the discharge port 27 is formed obliquely.

According to this second embodiment, the tank 24 is connected to the sleeve 12.
2 through a bearing 126, it can be rotated regardless of the rotation K of the sleeve 122. Therefore, the tank 24 can be rotated at high speed, and when the tank 24 is rotated at high speed, the toner stirred inside is efficiently charged.

Furthermore, a third embodiment of the present invention will be described. In this third embodiment, as shown in FIG. A plate 34 is provided.

This pressing plate 34 has a plurality of curved blades arranged in the axial direction inside the tank 24, and by bringing the toner 21 into contact with this pressing plate 34, the toner 21 is more effectively frictionally charged. Ru.

In this case, it goes without saying that if the material of the push plate 34 is selected in consideration of the frictional charging sequence with the toner 21, the toner 21 can be charged more effectively.

Furthermore, a fourth embodiment of the present invention will be described.

In this fourth embodiment, as shown in FIG. 5, a second toner in the shape of a water wheel with magnets arranged around the periphery is used to convey the toner to the tube opening 26, which is a spiral rotating body, inside the toner receiver 28. A carrier 36 is provided.

Note that a second toner conveyor 3 is provided above the toner inlet 26.
A toner scraping blade 37 for scraping off the toner 21 from the toner 6 is provided.

The operation of this embodiment will be explained.

After the toner 21 discharged from the toner discharge port 27 is transferred to the toner receiver 28 , the toner 21 is conveyed in the axial direction of the sleeve 22 by the first toner conveyor 35 and adheres to the sleeve 22 . A portion of the toner on the surface of the sleeve 22 is consumed in the developing area and returns to the toner receiver 28 again. Then, the returned toner 21 and the toner 21 not attached to the sleeve 22 are transported to the second toner transport device 36 side. The toner 21 that has reached the second toner conveyor 36 is attracted by the magnetic force of the magnet attached to the second toner conveyor 36 and is lifted by rotation, and when it reaches the toner scraping blade 37, it is scraped off by it. The toner enters the toner inlet 24 and returns to the toner stirring tank 24 again.

By making it recyclable in this way, the toner 21
is dramatically and stably charged.

Although not explained in the first to fourth embodiments, the toner outlet 27 is connected to the toner receiver 28 in order to prevent the toner 21 from being discharged in the developing area and staining the image.
A toner discharge control means may be provided to control the toner discharge port 27 so that the toner discharge port 27 is open only while the toner discharge port 27 is at the top of the toner discharge port 27 and closed during other periods.

Effects of the Invention According to the present invention, since the -component insulating magnetic toner is stirred in the toner stirring tank provided inside the sleeve, a sufficient charge can be applied to the toner without increasing the size of the device. There is an effect that it can be done.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a developing device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same taken along line A-A in FIG. 1, and FIG. FIG. 4 is a schematic cross-sectional view of a third embodiment of the present invention, FIG. 6 is a schematic partial cross-sectional view of a fourth embodiment of the present invention, and FIG. 6 is a schematic cross-sectional view of a conventional developing device. It is a schematic side sectional view showing an example. 21...-Component insulating magnetic toner, 22, 12
2... Sleeve, 23... Magnet, 24... Toner stirring tank, 35...
. . . 1st toner transport device, 36 . . . 2nd toner transport device. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 2/---A meeting! ! Affinity Menp P Main To 1-22-m-Sleeve 23-11 Majnef 1 Z

Claims (1)

[Claims] a cylindrical sleeve to which a one-component insulating magnetic toner is attached; a hollow magnet disposed inside the sleeve to attract and hold the toner on the sleeve;
A developing device includes a magnetically shielded toner agitation tank rotatably disposed inside the hollow part of the magnet.