JPS61270777A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To attain image formation of high density, high quality and high speed with small-sized and simple constitution by fixing a magnetism generating device on the photosensitive surface of a photosensitive body and magnetic bodies in the photosensitive body and vibrating toner electromagnetically. CONSTITUTION:A developing part 4 is provided with magnets 7, 8 of which S and N pole surfaces are opposed to the photosensitive surface of the photosensitive body, a toner case 5 arranged between respective magnets 7, 8, a developer 6 charged to the case 5, and bias power sources 11, 10 for forming alternate electric fields on the magnetic pole surfaces of respective magnets 7, 8. On the other hand, the magnetic bodies 12 opposed to the S and N pole surfaces of respective magnets are fixed in the photosensitive body 1. The lines of magnetic fore from the N pole of the magnet 8 and the S pole of the magnet 7 are reached to the magnetic bodies 12 through the photosensitive body 1, so that magnetic brushes 9 are formed in respective gaps between respective magnets and the photosensitive body 1 and the brushes 9 are constantly contacted with the photosensitive body 1. Consequently, the tone 6 in the case 5 is adhered to an electrostatic latent image on the photosensitive body 1 and smooth and uniform development can be attained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] [Background of the Invention] In general, a method for developing a charge latent image formed on an insulating recording medium or a photoconductive photoreceptor (hereinafter referred to as a recording medium) is disclosed in Japanese Patent Publication No. 58 The one described in JP-A-57112 is known. In this method, a magnetic brush is formed on a rotating developing roll, and while the developer is rotated, the developer is brought into contact with or close to a recording medium having a latent charge image, and the toner is attached to the charge and visualized. This is what I did. However, this method has the disadvantage that the apparatus becomes bulky and complicated.

On the other hand, as a method that does not have a rotation mechanism, fF-
There is a method described in -31977. However, this method has the disadvantage that developing efficiency is poor (high-density images cannot be obtained) and high-speed development cannot be performed.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic apparatus that eliminates such conventional drawbacks and is capable of forming high-density, high-quality, high-speed images with a simple configuration.

[Summary of the invention]

In order to achieve the above object, the present invention provides an electrophotographic apparatus in which development is performed by attaching toner to a photoreceptor on which a latent charge image is formed, in which one magnetic pole surface is provided on the photoreceptor surface of the photoreceptor. A magnetic generator is fixed so as to face each other, and a magnetic body is fixed in the photoreceptor at a position facing the one side magnetic pole surface via the photoreceptor surface of the photoreceptor, and the one side magnetic pole surface and the photoreceptor surface of the photoreceptor are connected to each other. A vibrating device is provided to vibrate the toner supplied by the magnetic brush formed between the two by electromagnetic means.

According to the present invention, since the relative position of the magnetism generating device and the magnetic material paired therewith is always fixed, a stable magnetic brush can be generated with respect to the photoreceptor, and therefore, the toner can be stabilized. supply becomes possible. In addition, since the toner moved by the magnetic brush is vibrated by electromagnetic means, the toner can be smoothly and uniformly attached to or removed from the photoreceptor. In this way, mechanical moving mechanisms can be eliminated as much as possible, making it possible to downsize the device. This, combined with a stable supply of toner and uniform and smooth adhesion and removal of toner, enables high-density, high-quality, high-speed images. Formation becomes possible.

[Embodiments of the invention]

Next, each embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a first embodiment. In FIG. 1, along the rotation direction (arrow) of a photoreceptor (for example, a photoconductor) 10, a charger 2, a developing section 4, a recording paper 13, and a recording paper 13 are arranged in the order of the image forming process.
, a transfer device 14, and a cleaning section are arranged.

The outline of the image forming process is as follows. After the photosensitive surface of the photoreceptor 1 is uniformly charged with corona by the charger 2, a light image 3t is irradiated onto the corona-charged photosensitive surface.

By irradiating this optical image 3, an expanded charge latent image is formed on the photosensitive surface. Next, this charge latent image is developed by a developing device 4, and toner is attached to the charge latent image corresponding to the optical image 3. Next, the toner is transferred onto recording paper 13 by transfer device 14 .

The transferred image is fixed on the recording paper 13 by printing or the like. On the other hand, the charge latent image on the photoreceptor 1 is removed by the afterimage erasing lamp 15.
The toner remaining on the photoreceptor 1 is removed by a cleaning device.

Thereafter, the above-mentioned series of steps are repeated in the same manner, and a desired image (including characters) can be obtained on the recording paper 13.

The developing section 4 includes a magnet 7 whose S-pole surface faces the photoreceptor surface of the photoreceptor 1, and a magnet 7 whose polar (i.e., N-pole) surface that is paired with the S-face faces the photoreceptor surface of the photoreceptor 1. A magnet 8, a toner container 5 formed between these magnets 7.8, and a toner container 5.
A bias power source 11 for forming an alternating electric field on the 8-pole surface of the magnet 7, and a bias power source 10 for forming an alternating electric field on the ON pole surface of the magnet 8. It consists of On the other hand, magnetic bodies 12 are fixed inside the photoreceptor drum 1 so as to face the 8-pole surface and the N-pole surface of each of the magnets 7 and 8, respectively.

Lines of magnetic force from the N-pole surface of the magnet 8 are generated toward the magnetic body 12 via the photoreceptor 1, and similarly, lines of magnetic force enter the S-pole surface of the magnet 7 from the magnetic body 1z via the photoreceptor 1. As a result, an air gap between the magnet 8 ON pole face and the photoreceptor 1 and an 8
A magnetic brush 9 is provided in each gap between the polar surface and the photoreceptor 1.
is formed.

The lower part of the toner container 5 is set so that it is almost covered by the magnetic brush 9. Although the magnetic body 12 may be magnetized, it is preferably a soft magnetic body that is not magnetized. The reason for this is that if the magnetic pusher 9 is magnetized, a portion of the magnetic pusher 9 will remain on the photoreceptor 1 when the developing device 4 is separated from the photoreceptor, that is, when it is taken out into the apparatus. . When the magnetic body 12 is arranged on the back side of the photoreceptor 1 in this way, the magnet 7.
Since a magnetic field is formed between the photoreceptor 8 and the photoreceptor 1, a magnetic brush is formed along the magnetic field, and the contact with the photoreceptor 1 becomes constant. Therefore, even if there is eccentricity in the rotation of the photoreceptor, the magnetic brush 9 will not be distorted or a gap will be generated.

A bias power supply 10.11 is connected to the magnet 7.8. The bias power supplies 10 and 11 constitute a vibrating device that applies a magnetic insulator pressure between the magnetic brush 9 and the surface of the photoreceptor 10, applies vibrating force to the magnetic brush 9, and adjusts the developability. The bias voltage may be either direct current or alternating current, but preferably one in which alternating current is superimposed on direct current. This is because direct current can adjust the fog and density of the image, and alternating current can improve the halftone reproducibility of the image and help the movement of toner within the magnetic brush. The presence of the alternating current electric field causes the toner or carrier to vibrate according to the sweeping frequency of the electric field, and the action of the magnetic brush 9 can facilitate the movement of the toner using the chain carrier as a medium. The sweep frequency is 1
0-1000) IZ can be used.

In this way, the toner 1 is adhered to the charged latent image on the photoreceptor 1, and development can be done smoothly and uniformly.

Note that when the magnetic brush 9 is a magnetic toner for development, a part of the magnetic brush 9 moves onto the photoreceptor 1, and the toner (magnetic toner) 6 in the toner container 5 is replaced by a new amount. The magnetic brush 9 must be replenished one after another. When the magnetic brush 9 is a two-component developer consisting of a magnetic carrier and a non-magnetic or magnetic toner, the toner in the magnetic brush 9 must be replenished from the toner in the toner container 5 for development. Application of the sweeping current using the AC bias voltage described above is optimal for this replenishment effect.

In this way, the toner image adhered and developed on the photoreceptor 1 is transferred to the record g13 by the transfer device 14. The toner on the recording paper is finally fixed (not shown) to complete the print.

On the other hand, even after the transfer, there is residual toner between the surfaces of the photoreceptor 1, so in order to use the photoreceptor 1 repeatedly, it is necessary to remove the residual toner, that is, to clean it. Conventionally, a rotating fur brush is used.

It used a rotating magnetic brush and a fixed rubber blade.

However, these methods have the disadvantage of requiring a complicated mechanism, increasing the size of the device, or placing an excessive load on the recording medium, resulting in an increase in the driving force for the recording medium and damage to the recording medium. Therefore, the cleaning mechanism of FIG. 1 according to the present embodiment uses a fixed magnetic brush 19 similar to that described above to eliminate the above-mentioned drawbacks.

In detail below, first, after transferring the photoreceptor (IK), the afterimage erasing lamp 15 irradiates the photoreceptor with light.
Erases the charge remaining in the unit. Instead of a lamp, a corona discharger may be used for neutralization or uniform charging to the same polarity as the toner. If the toner is uniformly charged, use a residual erasing lamp to remove the charge after toner cleaning. After the residual charge is erased, the residual toner is removed by a magnetic brush 19 which is vibrated by applying an Iasumi field and a magnetic field.

The bias power source 18 is preferably one that superimposes direct current and alternating current, similar to that of the developing device 4. That is, the direct current applies an attractive force to the toner to separate it from the surface of the photoconductor 1, and the alternating current applies a vibrational force to the toner and carrier, making it easier for the residual toner to separate from the photoconductor 1 and move within the magnetic brush 19. .

The toner separated from the photoreceptor 1 is collected in the waste toner container 16 by the action of the electric field and gravity inside the magnetic brush 19. An electrode 17 is provided on the inner surface (or outer surface) of the waste toner container 16, and a bias power source 21 for collecting toner is connected to this electrode 17.

This bias power supply 21 superimposes direct current or direct current and alternating current. The remaining toner may be collected in the waste toner container 16 by using an air flow.

The magnet 20 is provided with a magnetic body 12 similar to that disposed opposite the magnet 7.8 on the back side of the photoreceptor 1, so that the magnetic brush 19 can maintain good contact with the photoreceptor surface. In this way, the toner remaining on the photoreceptor is removed, and the photoreceptor can be used again.

As described above, according to this embodiment, the toner on the surface of the photoreceptor 10 can be supplied from the fixed magnetic brush 9 and removed from the surface of the photoreceptor 1 by the magnetic brush 19, so that the toner can be significantly reduced in size and simplified. Accordingly, it is possible to realize a recording device with the following characteristics. For example, when a drum-shaped photoreceptor 1 is used, it is possible to make the drum diameter t-30 or so.

FIG. 2 shows a second embodiment of the invention. In this second embodiment, a blowing magnetic field is added to the magnetic field formed between each magnet 7, 8, 20 and a magnetic body 12 facing each other, and the vibration of the magnetic brush is replaced by a method using a blowing field. This is done using a sweeping magnetic field. Note that the vibration caused by the sweeping magnetic field may be generated in combination with the sweeping electric field. The blowing magnetic field is applied to a coil 23 wound around each magnetic body 12 by an AC power source 22.
is generated by applying. In order to form a sweeping magnetic field, in addition to the method shown in Fig. 2, coils may be wound around the magnets 7, 8, and 20, and the magnetic body 12 that generates the sweeping magnetic field may be joined or placed close to each other. In order to simplify the structure and save space, it is preferable to provide it inside the recording medium as shown in FIG.

FIG. 3 shows a third embodiment of the present invention. In the embodiment shown in FIG. 1-2, the magnetic bodies 12 facing the magnets 7 and 81C were provided corresponding to each magnet, whereas in this embodiment, in order to simplify the structure, As shown in (a), the magnetic material 12 is commonly used for the magnets 7 and 8. In this case, in order to improve the magnetic permeability, as shown in Fig. 3(b)
The tip of the magnetic body 12 may be expanded as shown in FIG.

The polar arrangement of the magnets is not limited to that shown in the drawings, and may be similar to that shown in FIG. 4.

FIG. 4 shows a fourth embodiment of the present invention. The number of opposing magnetic bodies 12 is one as in FIG. 3, and the polarities of the magnets 7.8 are the same and opposite. The polarity of the cleaning magnet 20 corresponds to the polar arrangement of the magnets 7 and 8, and is set to a polarity that makes it easy for the magnetic brush to stand up. An electrode 24 is arranged so that a bias electric field for vibrating the magnetic brush 9t of the magnet 7.8 can be formed between the magnets 7 and 8, and an AC power source 25 is applied between the magnet 7 and the electrode 24. In this way, the magnetic brush 9 formed between the magnets 7 and 8 is soft, and the toner in the toner container 5 is easily drawn into the magnetic brush 9, so that toner can be replenished smoothly.

5 and 6 show another means for vibrating the magnetic brush generated in the manner shown in FIG. 4. This is a sixth example. In the fifth embodiment shown in FIG. 5, the sweeping magnetic field superimposed on the magnetic brush 9 is generated by a separately provided electromagnetic coil 27. The electromagnetic coil 27 is attached to the outside of the toner container 5 so as to apply a sweeping magnetic field between the magnets 7 and 8.

In the sixth embodiment shown in FIG. 6, the blowing magnetic field is not generated by an electromagnetic coil, but a movable magnetic body 26 is provided outside the toner container 5 so that it can reciprocate or rotate, and the magnetic field is mechanically pulsated. It was designed so that it would flow.

FIG. 7 shows a seventh embodiment of the present invention. In this embodiment, a magnet 27 is installed on the downstream side of magnet 8 in the same manner as magnets 7 and 8, and the magnetic field formed by this magnet 27 causes
The toner mt formed by the magnet 7.8 is for correction. By doing so, it is possible to reduce image fog, remove excessively adhered toner, and reproduce insufficiently developed areas, resulting in an image with good uniformity. This magnetic brush 9
A bias power supply 28 also applies bias bias pressure to a person to perform smooth correction. A toner receiver 30 attached to the magnet 27 is for collecting excess toner and scattered toner.

In each of the above embodiments, a photoreceptor 1t made of a photoconductor is used as the recording medium, but the present invention can be similarly applied to other recording bodies that form electrostatic latent images. Furthermore, if the recording medium in this embodiment is regarded as a carrier, instead of developing the recording medium directly, the developing device 4 coats a roll or belt-shaped developing member with toner gold, and the developing member is used to form a charge latent image. The present invention can also be applied to a device K that is developed by being brought close to or in contact with the surface of a recording medium.

Furthermore, it goes without saying that the present invention can be applied individually to the developing section and the cleaning section.

Furthermore, as mentioned above, the sweeping magnetic field and the sweeping electric field can be used not only individually but also in combination.

〔Effect of the invention〕

As described above, according to the present invention, high-speed, high-quality, high-speed image formation is possible with a small and simple configuration.

[Brief explanation of the drawing]

No. 1 is a configuration diagram showing the first embodiment of the electrophotographic apparatus of the present invention, FIG. 2 is a schematic diagram showing the second embodiment, and FIG. 3 (a
) is a schematic diagram showing the third embodiment, Φ) is a schematic diagram showing an example of a magnetic material, FIG. 4 is a schematic diagram showing the fourth embodiment, and FIG.
FIG. 6 is a schematic diagram showing the fifth embodiment, FIG. 6 is a schematic diagram showing the sixth embodiment, and FIG. 7 is a schematic diagram showing the seventh embodiment. 1... Photoreceptor, 2... Charger, 3... Optical image, 4...
...Developer, 7.8.20...Magnet, 9,9A,19
...Magnetic brush, 10, 11, 18.21...ノ(
Iasumi source.

Claims (1)

[Claims] 1. In an electrophotographic apparatus that performs development by applying toner to a rotating photoreceptor on which a latent charge image is formed, a magnetism generating device is fixed with one magnetic pole surface facing the photosensitive surface of the photoreceptor. and a magnetic body fixed within the photoreceptor at a position facing the one side magnetic pole surface via the photoreceptor surface of the photoreceptor;
An electrophotographic apparatus comprising: a vibration device that uses electromagnetic means to vibrate toner supplied by a magnetic brush formed between the one side magnetic pole surface and a photosensitive surface of a photosensitive member.