JPS6280681A - Developing device - Google Patents

Abstract

PURPOSE:To make quick recording possible by providing a developer agitating means to charge frictionally a toner efficiently in a short time. CONSTITUTION:A developer flow control plate 22 consisting of a magnetic body and a developer leak preventing plate 34 are provided, and thereby, lines of magnetic force from a sleeve 25 are always converted on the flow control plate 22 and the leak preventing plate 34 though positions of magnetic poles constituting a magnetic roll 23 to the sleeve 25 are changed by rotation of the magnetic roll 23. In a developer storage vessel 21, a developer agitating means 41 is provided between the flow control plate 2 and the leak preventing plate 34 so that this means 41 faces the surface of a developing roll 28, and the developer is agitated by this agitating means. Thus, a moving developer 24 is checked and is agitated to electrify a toner 26 quickly and effectively.

Description

[Detailed Description of the Invention] [Required] A developing device used in an electrophotographic device or an electrostatic recording device, in which only non-magnetic toner is selected especially in a developing area where a latent image carrier and a developing roller face each other. to enable transportation,
A developing device in which a developer stirring means is provided in a developer storage container to promote stirring of the developer and charge the toner more quickly and efficiently.

[Industrial application field]

The present invention relates to a developing device used in an electrophotographic device or an electrostatic recording device, and in particular, it selectively applies only non-magnetic toner to a developing area where a latent image carrier formed around a recording drum and a developing roller face each other. The present invention relates to a developing device in which the toner can be transported more quickly and more efficiently by providing an agitating means in the developer storage container to promote agitation of the developer and charge the toner more quickly and efficiently.

After uniformly charging the latent image carrier of a recording drum around which a latent image carrier made of a photoconductive layer of selenium (Se) or the like is formed, using a corona discharger or the like, the latent image carrier is An electrostatic latent image is formed by irradiating light and performing exposure corresponding to image information. Furthermore, electrophotographic recording devices that develop the electrostatic latent image by applying toner to it using a magnetic brush developer are widely used in copying devices and the like.

When developing using a two-component developer consisting of a non-magnetic toner and a magnetic carrier in the developing device of such an electrophotographic recording device, only the non-magnetic toner is selectively used, especially when recording in color. There is a demand for a device that can perform clear color recording as the toner is transported to the developing section, and that can sufficiently stir the developer in the developer storage container and charge the toner more quickly (and effectively). has been done.

[Conventional technology]

A schematic diagram of a developing device using a conventional two-component developer is shown in FIG.

As shown in FIG. 3, the conventional developing device consists of a carrier 1 made of magnetic particles and a toner 2 made of non-magnetic colored resin powder.
A developer storage container 4 containing a developer 3 comprising:
is provided close to the recording drum 1). Inside this developer storage container 4, there is a non-magnetic sleeve 5 that rotates in the six directions of arrows, and a non-magnetic sleeve 5 that is enclosed within this sleeve 5 and rotates in the opposite direction to the rotation direction of the sleeve 5 as shown in the direction of arrow B. A developing roller 7 composed of a magnetic roller 6 having a plurality of magnetic poles is provided.

Further, a spike cutting blade 8 made of a non-magnetic metal plate or the like is installed in the developer storage container B4 to regulate the height of the spikes of the developer 3 attached to the surface of the developing roller to a predetermined size.
Further, a developer discharging blade 9 made of a non-magnetic resin plate or the like is provided for discharging the developer 3 that has returned to the storage container 4 after being attached to the surface of the developing roller 7 without being developed.

To explain the operation of such a developing device, the developer 3 contained in the developer storage container 4 is moved by the magnetic roller 6.
It is attracted to the surface of the sleeve 5 by the magnetic force. Here, as shown in FIG. 4, the magnetic roller 6 rotates along the direction of arrow B, and the sleeve 5 rotates along the direction of arrow 6, so that the spikes of developer 3 consisting of toner 2 and carrier 1 rotates according to the rotation of the magnetic roller 6, while
1) in the six directions of the arrow! ! sent.

As shown in FIG. 3, the developer 3 adsorbed in the form of rice ears on the sleeve 5 moves along the direction of rotation of the sleeve 5 shown by arrow A, and is moved to the outlet of the developer storage container 4. A predetermined thickness is defined by the ear cutting blade 8,
It is further conveyed along the six directions of arrows. The toner 2 is then supplied and adhered to the electrostatic latent image formed on the recording drum 11 in the development area where the conveyed developer 3 comes into contact with the recording drum 1) on which the latent image carrier 10 is formed. and development is performed.

After the development is completed, the developer 3 is further conveyed on the sleeve 5 and collected into the developer storage container 4. Furthermore, the developer 3 is peeled off from the sleeve 5 by a developer scraping blade 9.
The toner 2 is stirred by a stirring means (not shown), and the amount of toner 2 consumed by development is replenished, and then the developing device repeats the same operation as described above.

[Problem that the invention seeks to solve]

However, in a developing device that uses such a two-component developer, the toner concentration of the developer has a large effect on the recording quality, and if the toner concentration is high, when the developed toner image is transferred to recording paper, the transfer Background stains occur in the background of the printed image. Further, when the toner concentration decreases, the image becomes thinner or is not developed, and furthermore, the carrier 1 adheres to the image.

Therefore, in such an apparatus, a toner concentration sensor must be provided to manage the toner concentration, and toner must be supplied in accordance with the toner concentration, making maintenance and management of the developing device complicated and problematic.

Furthermore, in such a two-component developer, since development is carried out by bringing the developer 3 into contact with the recording drum II, there is a problem in that the surface of the recording drum 1) is rubbed by the carrier 1 and scratches occur.

Furthermore, as previously proposed by the inventors, the recording drum 1
) In the case of color recording, in which latent image formation and development steps are repeated multiple times during one rotation, the previously formed toner image may be destroyed during the second and subsequent stages of development, or color mixing may occur. There is a problem that causes

Incidentally, in such color recording, the present inventors have previously proposed a method in which a one-component magnetic toner is used for the second and subsequent stages of development.

However, since the one-component magnetic toner described above has a structure in which magnetic powder is added to colored resin powder, there is a problem in that clear color recording cannot be achieved.

Another problem is that undeveloped toner that is not attached to the latent image carrier 10 of the recording drum II but is attached to the sleeve 5 and collected in the developer storage container 4 is scattered around. There is a problem in that the particles are scattered outside the container 4.

Further, in such an apparatus, there is a problem that the developer is not sufficiently agitated and the toner is not charged efficiently.

[Means for solving problems]

As shown in FIG. 1, the developing device of the present invention includes a non-magnetic sleeve 25, a magnetic roller 23 enclosed in the non-magnetic sleeve 25 and rotating together with the non-magnetic sleeve 25, and a developer in the developer storage container 21. Magnetic roller 2 is installed at the outlet 33.
3 and a non-magnetic sleeve 25, a developer flow regulating plate 22 made of a magnetic material is provided, and a developer leakage prevention plate 34 made of a magnetic material is provided at the developer inlet port 30. The rotating direction of the non-magnetic sleeve 25 is the direction in which the developer 24 is directed from the developer outlet 33 toward the latent image carrier 31 .

Furthermore, within the developer storage container 21, the developing roller 2 is disposed between the developer flow regulating plate 22 and the developer leakage prevention plate 34.
A stirring means 41 is provided opposite to 8.

[Function] The developing device of the present invention is provided with the developer flow regulating plate 22 and the developer leakage prevention plate 34 made of magnetic material, so that the magnetic roller 23
Even if the position of the magnetic poles constituting the magnetic roller 23 relative to the sleeve 25 changes due to the rotation of the flow regulating plate 22
, and the leakage prevention plate 34 so that the lines of magnetic force from the sleeve 25 are focused.

Then, a magnetic brush is formed between the magnetic pole of the magnetic roller 23 and the flow regulating plate 22, and the carrier 27 is prevented from being conveyed past the flow regulating plate 22 by the magnetic brush, so that only the toner 26 reaches the developing area. It was designed to reach this point.

Furthermore, at this time, the non-magnetic toner 26 on the sleeve 25 is charged by frictional charging with the magnetic carrier 27 and the sleeve 25, and forms a layer of non-magnetic toner 26 on the surface of the developing roller 28 by mirror image force. Do it like this.

Furthermore, a magnetic brush is formed between the sleeve 25 and the developer leak prevention plate 34 made of a magnetic material, and this magnetic brush removes a layer of toner that has not been developed onto the latent image carrier and has returned to the developer storage container 21 to the outside. Collect without scattering.

In addition, inside the developer storage container 21, the flow regulating plate 2
A developer stirring means 41 is provided between the leakage prevention plate 34 and the developer roller 28 so as to face the surface of the developing roller 28, and by stirring the developer with this stirring means, the movement of the developer 24 is blocked. 1, so that the toner 26 is charged more quickly and effectively.

C Embodiment] Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

As shown in FIG. 1, the developing device of the present invention includes a developer container containing a two-component developer 24, which is a mixture of a toner 26 made of non-magnetic colored resin powder and a carrier 27 made of magnetic powder. 21, a developer flow regulating plate 22 made of a magnetic material is provided at a position close to a developing roller 28 made of a non-magnetic sleeve 25 and a magnetic roller 23 contained therein. .

Furthermore, a developer leakage prevention plate 34 made of a magnetic material is provided on the side of the developer carrying-in port 30 of the developer storage container 21 .

In the developer storage container 21, a stirring means 41 is provided between the flow regulating plate 22 and the leakage prevention plate 34 of the developer 24, facing the developing roller 28.

This stirring means 41 is formed of an L-shaped flat plate-like resin or metal plate as shown in FIG. 2, and is kept in a fixed state.

The operation of such a developing device of the present invention will be explained.

The two-component developer 24 consisting of the toner 26 and carrier 27 described above is attracted to the surface of the developing roller 28 by the magnetic force of the magnetic roller 23 . At this time, both the magnetic roller 23 and the non-magnetic sleeve 25 rotate counterclockwise as shown by arrows C and D, and the developer 24 is also fed counterclockwise.

Here, since the developer 24 is conveyed in the same direction as the rotational direction of the magnetic roller 23, the magnetic roller 23 of the developer 24
The speed at which the developer 24 is transported by the sleeve 2
5, the conveyance speed is set higher.

As a result, the developer 2 adsorbed on the surface of the developing roller 28
4 is conveyed in the rotational direction of the non-magnetic sleeve 25 while performing rotational movement due to the movement of the magnetic pole of the magnetic roller 23. Further, due to the rotational movement of the developer 24 and friction with the sleeve 25, the toner 26 and the carrier 27 each have charges of opposite polarity.

Further, the developer 24 is stopped by a developer stirring blade 41 provided opposite the developing roller 28 , and a portion of the developer 24 passes through the gap between the stirring blade 41 and the developing roller 28 and is conveyed on the developing roller 28 . Further, the remaining developer 24 that has not passed through the above-mentioned gap moves away from the developing roller 28 along the stirring blade 41 and is returned in the opposite direction to the developer transport direction.

As a result, the developer 24 is more reliably stirred and triboelectrically charged. Then, when the flow regulating plate 22 is defeated, since the flow regulating plate 22 is made of a magnetic material, the magnetic roller 2
Since the polarity is opposite to that of sleeve 2, the developer 24 is
5 surface and the flow regulating plate 22 are connected by a magnetic brush.

Further, the developer 24 stays in the vicinity of the flow regulating plate 22 , and finally advances upward along the flow regulating plate 22 , slips on the surface layer of the developer 24 midway through, and reaches the bottom of the developer storage container 21 .

When the developer 24 forms a magnetic brush between the flow regulating plate 22 and the sleeve 25, the non-magnetic toner 25 electrostatically adheres to the non-magnetic sleeve 25 by image force.

Incidentally, the non-magnetic toner 26 adheres to the non-magnetic sleeve 25 even during the conveyance until reaching the flow regulation Fj, 22. Then, as the non-magnetic sleeve 25 rotates, it is transported to the developing area. In the developing area where the developing roller 28 and the recording drum 29 face each other, the non-magnetic sleeve 25 and the recording drum 29
If a developing bias is applied by the developing bias power supply 32 during this time, the l.ner 26 will adhere to the electrostatic latent image formed on the latent image carrier 31 around the recording drum 29, and development will be performed. . The toner layer 268 that was not used for development is further transported and reaches the storage container 21.

However, the toner layer 26A was returned to the developer storage container 2.
A developer leakage prevention plate 34 made of a magnetic material is provided at the inlet portion 30 of 1, and this leakage prevention plate 3.1 has a magnetic field between it and the non-magnetic sleeve 25, similar to the flow regulation plate 22 described above. Form a brush. This magnetic brush prevents the developer 24 in the developer storage container 21 from flowing out, and the returning toner layer 268 is blocked by the magnetic brush, peeled off from the sleeve 25, and removed from the magnetic brush. Adsorbed by carrier. The magnetic brush attracts the collected toner and conveys it toward the flow regulating plate 22 while rotating on its axis.

Note that the toner lost during development is stored in the developer storage container 2.
1. A toner storage chamber 52 formed by a partition plate 51 provided in 1.
The toner is supplied by the toner supply roller 53.

According to this embodiment, together with the sleeve 25, the magnetic roller 23
Since the developer is rotated, the magnetic brush of the developer rotates on its own axis, and the toner and carrier are agitated. This is done more fully than when sending. As a result, the toner is reliably charged in a short time during transportation, and a layer of toner can be easily formed on the surface of the nonmagnetic sleeve.

In other words, it is possible to apply the present invention to high-speed recording, which is difficult to achieve with a developer conveyance system based on the rotation of only the non-magnetic sleeve 25.

In addition, since the stirring blade 41 is provided, the toner 26
Charging is performed more efficiently.

Furthermore, since the developer conveyance speed due to the rotation of the non-magnetic sleeve 25 is higher than the conveyance speed due to the magnetic roller 23, the toner peeled off on the leak prevention plate 34 is always conveyed together with the carrier in the direction of the flow regulating plate 22, and the flow is prevented. Since a magnetic brush is formed between the regulating plate 22 and the leak prevention plate 34 and the sleeve 25, the carrier 27, which is a magnetic particle, is able to absorb the developer in the developer storage container 21 (the upper opening 33 and the loading opening 30).
This will prevent leakage to the outside.

As another embodiment, as shown in FIG. 2, the stirring blade 41 may have a bending point of the L-shape as a fulcrum 42 and move around this fulcrum 42 as the center of rotation.

Further, as the developer stirring means, an impeller, a screw shaft, or the like may be used in addition to the stirring blade 41, and any number of impellers or screw shafts may be used.

In addition to the developing bias, there is also a flow regulating plate 22 and a sleeve 25.
, the toner 26 is placed between the stirring blade 41 and the sleeve 250.
A voltage may be applied to generate an electric field directed toward the sleeve 25.

In this embodiment, the magnetic roller 23 and the non-magnetic sleeve 25 are
Although the description has been made with both rotations in the same direction (counterclockwise), the rotation direction of the magnetic roller 23 does not matter as long as the non-magnetic sleeve 25 for conveying one layer of toner rotates counterclockwise. Furthermore, the direction in which the developer 24 is conveyed in the developer storage container 21 does not necessarily have to be counterclockwise; It is determined by the balance between

Furthermore, in addition to this embodiment, a device in which only the magnetic roller 23 is fixed is also possible. In this case, each plate 22.3 is arranged so that a magnetic brush is formed between the sleeve 25 and the developer flow regulating plate 22, and between the sleeve 25 and the developer leak prevention plate 34.
It is preferable to arrange the δ circumference so that the magnetic pole of the magnetic roller 23 is located at a position opposite to the magnetic roller 23.

Further, the developing bias voltage may be either direct current or alternating current.

[Effects of the Invention] According to the developing device of the present invention, only the carrier of the two-component developer can be reliably and selectively blocked by the flow regulating plate, and only one layer of toner can be transported to the developing area. , it is not necessary to strictly control the toner concentration, and the apparatus becomes simple and low-cost.

In addition, since there is no carrier in the development area, the surface of the recording drum will not be damaged, and since development is performed using only a single layer of toner, soft development can be obtained, and when used for color recording, it is clear and has good quality without image destruction or color mixing. This has the effect of being able to record.

Furthermore, since the magnetic roller is rotated, the toner can be sufficiently agitated, the toner can be charged easily and reliably in a short time, and high-speed recording is possible.

In addition, since a developer stirring means is provided, the developer can be stirred reliably, and the toner can be frictionally charged efficiently in a short time.
This facilitates the formation of a single layer of toner on the sleeve 25, and has the effect of enabling high-speed recording.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the developing device of the present invention, FIG. 2 is an explanatory diagram of the stirring means in the developing device of the present invention, and FIG. 3 is an explanatory diagram showing a conventional developing device. , FIG. 4 is an explanatory diagram showing the state of the developer in the developing device. In the figure, 21 is a developer storage container, 22 is a flow regulating plate, 23 is a magnetic roller, 24 is a developer, 25 is a sleeve, 26 is a toner, 268 is a toner layer, 27 is a carrier, and 28 is a developing roller. , 29 is a recording drum, 30 is a developer inlet port, 31 is a latent image carrier, 32 is a developing bias power source, and 33 is a developer I
Jl exit section, 34 is a developer leak prevention device, 41 is a stirring blade, 42 is a fulcrum, 51 is a partition plate, 52 is a toner storage container, 53 is a toner supply roller, C is an arrow indicating the rotation direction of the magnetic roller, D is an arrow indicating the direction of rotation of the sleeve. Agent Patent Attorney Sada Igata - 44-Ang B ear/l engineering image fnt diagram @ 1 Figure 2

Claims (4)

[Claims] (1) A developer storage container containing a two-component developer consisting of a magnetic carrier and a non-magnetic toner, a developing roller consisting of a rotatable non-magnetic sleeve and a magnetic roller included therein, the non-magnetic sleeve; and a developing device that rotates at least one of magnetic rollers to convey the two-component developer along the surface of the sleeve, a rotatable non-magnetic sleeve (25) and a rotatable non-magnetic sleeve (25) contained in the non-magnetic sleeve (25). a developing roller (28) consisting of a magnetic roller (23); and a developer flow regulating plate made of a magnetic material and facing the developing roller (28) at the developer outlet (33) of the developer storage container (21). (22), and a developer leak prevention plate (34) made of a magnetic material and facing the developing roller (28) at the developer inlet port (30) of the developer storage container (21).
) is disposed in the developer storage container (21) between the developer flow regulating plate (22) and the developer leak prevention plate (34), facing the developing roller (28), and is rotationally driven. A developer stirring means (41) is provided, and the non-magnetic sleeve (25
), the developer (24) passes through the developer outlet (3).
3) A developing device characterized in that the direction is directed closer to the latent image carrier (31). (2) The non-magnetic sleeve (25) and the magnetic roller (23)
2. The developing device according to claim 1, wherein the developing device rotates simultaneously the developing device. (3) The developing device according to claim 1, wherein the magnetic roller (23) is fixed and the non-magnetic sleeve (25) is rotated. (4) The developing device according to any one of claims 1, 2 and 3, wherein the developer stirring means (41) is a developer stirring blade made of a non-magnetic plate.