JPS6263968A - Developing device - Google Patents

Abstract

PURPOSE:To attain stable development by triboelectrifying a nonmagnetic toner on a sleeve by rotation and stopping transfer of magnetic material particles to a developing part by a carrying preventing means of magnetic material particles and carrying only a nonmagnetic toner layer to the developing part. CONSTITUTION:Magnetic material particles 16 are formed like a continuous chain on N poles of a magnetic roll 13 and are inclined in the direction opposite to the rotation direction of the magnetic roll 13 by rotation of the magnetic roll 13. Magnetic material particles 16 are moved to be parallel with the surface of a sleeve 12 by rotation of the magnetic roll 13 and are rotated around front end parts of rotation and are moved to be vertical on S poles of the magnetic roll 13. The nap of magnetic material particles 16 are rotated on the sleeve 12 in accordance with movement of magnetic poles while describing half circles in this manner, and a nonmagnetic toner 17 carried together with magnetic material particles 16 is brought into contact with the sleeve 12 with friction and is electrified by this friction and is stuck onto the sleeve 12. Thus, stable development is possible.

Description

[Detailed Description of the Invention] [Summary] This is a small and compact developing device, in which component non-magnetic toner and magnetic particles are stored in a developer container, and then the magnetic particles are rotated by the rotation of a magnetic roller. This is a developing device in which the one-component non-magnetic toner on the sleeve is charged by this rotational movement, and the conveyance of magnetic particles is prevented and only the one-component non-magnetic toner is conveyed to the developing section. To obtain a developing device that can also be applied to

[Industrial application field]

The present invention relates to an improvement in a developing device, and in particular uses a mixture of non-magnetic toner and magnetic particles to triboelectrically charge the non-magnetic toner on the sleeve by the rotational movement of the magnetic particles on the sleeve of a developing roller. The present invention relates to a developing device that forms a layer of non-magnetic toner on a sleeve of a developing device by charging, and visualizes a latent image on a recording medium using this layer of non-magnetic toner.

After uniformly charging the surface of a photosensitive drum on which a photoconductive layer of selenium (Se) or the like is formed using a corona discharger or the like, the photoconductive layer is irradiated with light such as a laser beam. Exposure corresponding to image information is performed to form an electrostatic latent image. Furthermore, electrostatic recording devices that develop the electrostatic latent image by applying toner to it using a magnetic brush developer are widely used in copying machines and the like.

In developing in such an electrostatic recording device, there is a demand for a developing device using non-magnetic toner, especially when performing color print recording.

[Conventional technology]

Generally, as a developer for developing a latent image formed on a recording medium of such a photosensitive drum, there are two-component developers made of non-magnetic toner and a carrier, and one-component developers made only of toner. In a two-component developer, the mixing ratio of toner and carrier, that is, the toner concentration, must always be maintained at a constant value. For this reason, it is inevitable that the developing device itself becomes complicated and large, such as by using a toner concentration sensor or providing a developer stirring mechanism.

On the other hand, a one-component developer made only of toner does not require the management of toner concentration, is easy to handle, and allows the development device to be downsized.

However, in the -component developer, magnetic toner containing magnetic powder is generally used, especially when performing color recording.
Because of this magnetic powder, it was not possible to obtain toner with vivid colors, and it was not possible to perform vivid color recording.

As a method for solving these problems, a developing device shown in FIG. 5 has been proposed. Carrier 3 inside developer container 4
and the non-magnetic toner 5 are weakly coupled by electrostatic force and are attracted to the magnet 1 fixed within the sleeve 2. This adsorbed two-component developer is conveyed to the magnetic blade 6 by the rotation of the sleeve 2. During this transportation process,
The two-component developer consisting of the non-magnetic toner 5 and the carrier 3 is attracted to the surface of the sleeve 2 by magnetic force and rubs against the surface of the sleeve 2 every time it passes over the magnet. is also attracted by electrostatic force.

In the magnetic blade 6, due to the magnetic field with the magnet, the carrier particles are retained and scraped off from the surface of the sleeve 2.

On the other hand, the non-magnetic toner 5 adhering to the surface of the sleeve 2 forms a toner layer on the sleeve surface, passes through the magnetic blade 6, and is supplied to the developing section where the photoreceptor 7 and the sleeve 2 are close to each other. The developer scraped off by the magnetic blade 6 is stirred by the blade 8 and sucked onto the sleeve 2 again. In the developing section, by applying a developing bias voltage between the sleeve 2 and the photoreceptor 7, the toner on the sleeve 2 was made to adhere to the electrostatic latent image formed on the photoreceptor.

[Problem that the invention seeks to solve]

However, in such an apparatus, sufficient friction between the sleeve 2 and the carrier 3 and the non-magnetic toner 5 is not achieved.
Non-magnetic toner used in normal two-component developers has less triboelectric charge, and therefore less toner adheres to the sleeve surface. Therefore, there is a problem in that it is difficult to perform sufficient development.

[Means for solving problems]

In the developing device of the present invention, as shown in FIG. The body particles 16 are rotated in a state where they stand up, and this rotational movement causes the non-magnetic toner 17 to be tribo-electrified on the sleeve 12.The non-magnetic toner 17 is attached to the sleeve 12 by the electric charge caused by this tribo-electrification, and the toner is layered. After forming the non-magnetic toner 1, the transfer of the magnetic particles 16 to the developing section is stopped by means 18 and 19 for preventing the magnetic particles 16 from being transported near the sleeve 12.
Only the 5th layer is transported to the developing section.

[Effect]

In the developing device of the present invention, magnetic particles 16 mixed with non-magnetic toner 17 and stored in a developing container 11 are transferred to a magnetic roller 13.
The spikes are rotated on the sleeve 12 in a state where they stand up. This rotational movement causes the non-magnetic toner 17 to be frictionally charged on the sleeve 12, and this charging causes the non-magnetic toner 17 to adhere to the sleeve 12 to form a uniform layer of toner.

By preventing the magnetic particles 16 from being conveyed to the developing section by the permanent magnet 18 or the blade 19, only the non-magnetic toner 17 layer is conveyed to the developing section. Try to get a color print record.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram for explaining the developing device of the present invention.
As shown in the figure, the particle size is 10 to 2 in the developer storage container 11.
A mixture of magnetic particles 16 made by kneading magnetic powder into resin and non-magnetic toner 17 is accommodated at a length of 0.17 m.

This non-magnetic toner 17 is replenished into the developer container 11 from a toner hopper 20 installed in the developer container 11 using a toner supply roller 21 . Further, in this container 11, a sleeve 12 made of non-magnetic aluminum and a magnetic roller 13 enclosed within the sleeve 12 and having eight magnetic poles and a magnetic force of 800 Gauss are installed. Further, the sleeve 12 and the photosensitive drum 15 are close to the developing section, and the sleeve 12 is close to the photosensitive drum 15.
A permanent magnet 18 for stopping the conveyance of the magnetic particles 16 is installed at a position close to.

A photosensitive drum 15 with such a sleeve 13 shown by arrow A
The photosensitive drum 15 is rotated in the direction of arrow B so as to be opposite to the rotating direction of the photosensitive drum 15 and at the same rotational speed as the photosensitive drum 15.

Further, the direction of rotation of the magnetic roller 13 is also in the direction of arrow C, so that it is the same direction as the direction of rotation of the sleeve 12.

As shown in FIG. 2(a), magnetic particles 16 are formed in a chain on the north pole of the magnetic roller 13 due to the magnetic force of the magnetic roller 13.
As shown in FIG. 2, the rotation of the magnetic roller 13 causes the magnetic roller 13 to fall in the direction opposite to the rotational movement direction of the magnetic roller 13.

As shown in FIG. Figure 2! As shown in d+, Figure 2 (al
~(It now rotates around the part that was the tip of rotation in C1, and moves to a position perpendicular to the S pole of the magnetic roller 13 as shown in FIG. 2 (el) due to the rotation of the magnetic roller. .

In this way, the ears formed by the magnetic particles 16 rotate in a semicircular manner on the sleeve 12 in response to the movement of the magnetic pole of the magnetic roller 13. The non-magnetic toner 1 conveyed together with the magnetic particles 16 by this rotational movement
7 comes into frictional contact with the sleeve 12, and is electrically charged by this friction and adheres to the sleeve 12.

The non-magnetic toner 17 adhering to the sleeve 12 is conveyed to the developing section by the rotation of the sleeve.

A permanent magnet 18 is placed close to this sleeve 12 as shown in FIG. Then, the magnetic particles 16 on the sleeve 12 that have been conveyed are moved by the magnetic field formed between the permanent magnet 18 and the magnetic roller 13.
The movement of is stopped, and at this position, the above-mentioned rotational movement is performed steadily.

As a result, the magnetic particles 16 are not transported to the developing section.

The non-magnetic toner 17 thus conveyed to the developing section of the photosensitive drum 15 is transferred between the photosensitive drum 15 and the sleeve 12.
By applying a developing bias voltage between
Development is performed by adhering to the electrostatic latent image formed on 5.

In this embodiment, as shown in FIG. 4Lb) and FIG. 4C, the sleeve 12 and the magnetic roller 13 are rotated in the same direction, so that the sleeve 12 rotates the magnetic particles 16.
The direction of conveyance is reversed to the direction of conveyance by the magnetic roller 13.

The reason for this is that when the rotation directions of the sleeve 12 and the magnetic roller are opposite to each other as shown in FIG. In comparison with Fig. 4 (
'b), as shown in Fig. 4 (C1), the movement of the magnetic particles 16 is stopped by the permanent magnet 18, and the rotational movement shown in Fig. 2 (al to 2 tel) is performed at that location. This is because when the magnetic particles 16 are retained, the area covered by the magnetic particles 11 on the surface of the sleeve 12 increases.

Therefore, the area of the magnetic particles 16 covering the surface of the sleeve 12 is increased, the charging efficiency of the non-magnetic toner 17 is improved, and a uniform layer of toner can be formed on the surface of the sleeve 12.

Here, in FIG. 4fcl, the permanent magnets 18 are arranged not only at the position shown in FIG. 1 but also at a position opposite to each other with the developing roller 14 in between.

In addition, as shown in Figure 4), sleeve 1 is shown in Figure 4 (tel).
2 and the conveying direction of the magnetic particles 16 and the magnetic roller 13
When the conveying direction of the magnetic particles 16 is reversed, the speed at which the magnetic particles 16 are conveyed by the magnetic roller 13 and the speed at which the magnetic particles 16 are conveyed by the sleeve 12 are made approximately equal to each other. 16 is sleeve 1
The area covering the two surfaces can be made even larger, and it becomes more effective for forming a layer of toner on the sleeve 12 surface.

Here, when the circumferential speed of the sleeve is 5 (up to) 8 ec and the rotation speed of the magnetic roller 13 is 1400 to 1600 rpm, the speed at which the magnetic particles 16 are conveyed by the magnetic roller 13 and the magnetic particle 16 can be conveyed by the sleeve 12 at approximately equal speeds, thereby forming a more uniform layer of toner on the sleeve.

Furthermore, as another embodiment of the present invention, as shown in FIG. 1, the permanent magnet 18 described above is not used as a means for removing the magnetic particles 14, and instead of the permanent magnet 12, a sleeve 12 is installed in a portion close to the developing section. A plate-shaped blade 19 may be provided that covers the entire surface of the sleeve 12 and contacts the sleeve 12, and this blade 19 may prevent the magnetic particles 16 from being conveyed to the developing section.

Further, the permanent magnet 18 and the blade 19 may be provided together,
Furthermore, as shown in FIG. 4 (C1), the permanent magnets 18 and the blades 19 may be disposed facing each other in the upper direction with the developing roller 14 in between.

〔Effect of the invention〕

As described above, according to the developing device of the present invention, by rotating the spikes formed by the magnetic particles held on the non-magnetic sleeve at high speed, the non-magnetic toner can be easily triboelectrified by the sleeve. As a result, the non-magnetic toner can be stably adhered to the sleeve as a single toner layer, resulting in the effect that stable development can be performed.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram for explaining the developing device of the present invention, Fig. 2 (al to Fig. 2te+ is a schematic diagram showing the moving direction of magnetic particles in the present invention, 4 (al to 4) is a schematic diagram showing the movement state of magnetic particles in the vicinity of the developing section in the apparatus of
Figure (C1 is a schematic diagram showing the retention state of magnetic particles in the vicinity of the developing section of the apparatus of the present invention, and Figure 5 is a schematic % formula for explaining the conventional developing apparatus. 11 is a developing container, 12 is a sleeve, 13 is a magnetic roller;
14 is a developing roller, 15 is a photosensitive drum, 16 is a magnetic particle, 17 is a non-magnetic toner, 18 is a permanent magnet, 19 is a blade, 20 is a toner hopper, 21 is a toner supply roller, A is a moving direction of the photosensitive drum , B is an arrow showing the direction of rotation of the sleeve, and C is an arrow showing the direction of rotation of the magnetic roller. Determining the attack 1 of the present invention 73r, Seven history tans same figure 1 figure 11.1 子赳釦学 1j屏I YOSU 孜疯 figure 2 figure n hard f! J of j” ν1illft. 5th T-order N diagram

Claims (4)

[Claims] (1) A developing roller consisting of a developing container (11) containing developer, a sleeve (12) installed in the developing container (11), and a magnetic roller (13) contained in the sleeve (12). (14), the developer is conveyed by a developing roller (14), and a latent image forming medium (15) rotating opposite to the developing roller (14) is located in a developing section adjacent to the developing roller (14). In the device for attaching the developer to the latent image formed on the latent image forming medium (15), a developer container containing a mixture of magnetic particles (16) and non-magnetic toner (17); (11), a developing roller (14) which is installed in the container (11) and consists of a rotating non-magnetic sleeve (12) and a magnetic roller (13) contained therein.
are provided, and magnetic particles (
16) to the developing section;
, 19) are provided, the mixture is conveyed by the rotation of the sleeve (12) and the magnetic roller (13), and the magnetic particles (16) are conveyed.
) is rotated on the sleeve (12) in a state where it stands up, and the non-magnetic toner (17) is moved onto the sleeve (12) by the rotational movement.
12) forming a non-magnetic toner (17) layer on the sleeve (12) by triboelectrically charging the non-magnetic toner (17) by means (18, 19) for preventing transport of the magnetic particles (16); A developing device characterized in that only a layer is transported to a developing section. (2) The direction of rotation of the sleeve (12) and the direction of rotation of the magnetic roller (13) are made the same, and the magnetic particles (1
6) The developing device according to claim 1, wherein the direction of conveyance by the sleeve (12) and the direction of conveyance by the magnetic roller (13) are opposite directions. (3) Adjust the conveyance speed of the magnetic particles (16) by the magnetic roller (14) to the sleeve (1) of the magnetic particles (16).
The developing device according to claims (1) and (2), characterized in that the conveyance speed is approximately equal to the conveyance speed according to (2). (4) Claim (1) characterized in that the means for preventing the conveyance of the magnetic particles is a permanent magnet (18) or a blade (19) close to the sleeve (12). The developing device according to items (3) to (3) above.