JPH06230679A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To provide an excellent electrophotographic device which is simple and small in structure, provides high resolution, and can cope with a high speed process. CONSTITUTION:The device uses a photosensitive drum 14 with a fixed magnet 15 inside. After an electrostatic latent image is formed, it is brought into contact with magnetic developer 20 in a developer container 19, and the developer is attracted to the surface of the photosensitive body by means of a magnetic force. Further, by passing an electrode roller 21 to which an AC voltage is applied, the toner remains only in an image part, to be developed and actualized. As a means for carrying the magnetic developer 20, supplied to the photosensitive body 14, to the development place, the device has a magnetic field generating means that generates a magnetic field in the direction of the periphery of the photosensitive body, on the surface of the photosensitive body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus applicable to printers, facsimiles and the like.

[0002]

2. Description of the Related Art Conventionally, a two-component developing method using a developer composed of a toner and a carrier has been widely used in an electrophotographic method, but in recent years, a one-component developing method has been used in order to reduce the size of an image forming portion and reduce the cost. Is being developed. As an electrophotographic apparatus using such a one-component developing method, there is an apparatus shown in FIG. 16 proposed by the applicants in Japanese Patent Application No. 3-345990. In FIG. 16, 1 is an organic photosensitive drum in which phthalocyanine is dispersed in a polyester binder resin, 2
Is a magnet fixed coaxially with the photoconductor 1. 3 is a corona charger for charging the photosensitive member, 4 is a grid electrode for controlling the charging potential of the photosensitive member, 5 is signal light, 6 is a developer reservoir, 7 is a magnetic one-component toner, and 8 is a developer reservoir. This is a damper for smoothing the flow of the developer and preventing the developer from being crushed by its own weight and clogged between the photoconductor and the electrode roller. The magnet 2 faces the developer reservoir 6 (θ =
The magnetic pole is formed at the 10 ° portion. Reference numeral 9 is an aluminum electrode roller having a magnet 10 inside, 11 is an AC high voltage power source for applying a voltage to the electrode roller, 12 is a scraper made of a polyester film for scraping off the toner on the electrode roller, and 13 is toner on the photoconductor. A transfer corona charger that transfers an image to paper.

This electrophotographic developing device is shown in FIG.
The operation will be described with reference to FIG. The photoconductor 1 was charged to −500V by the corona charger 3. The photoconductor 1 was irradiated with laser light 5 to form an electrostatic latent image. Toner 7 was attached to the surface of the photoconductor 1 in the developer reservoir 6 by magnetic force. Next, the photoconductor 1 was passed in front of the electrode roller 9. At this time, -3 is applied to the electrode roller 9 by the AC high voltage power supply 11.
An AC voltage of 750 V 0-p (frequency 1 kHz) superposed with a DC voltage of 50 V was applied. Then, the toner was collected from the photoconductor 1 toward the electrode roller 9, and the negative-positive inverted toner image remained only on the image portion on the photoconductor 1. The toner adhering to the electrode roller 9 rotating in the direction of the arrow was scraped off by the scraper 12, returned to the developer reservoir 6 and used for the next image formation. The toner image thus obtained on the photoconductor 1 is transferred onto a sheet (not shown) of the transfer corona charger 1.
After transferring by No. 3, it was heat-fixed by a fixing device (not shown).

[0004]

When printing is performed using such an electrophotographic developing device, a high temperature and high humidity environment (33
Under the conditions of (° C., 85% RH), the character image was good, but there was a problem that the image density of the solid image was low.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic developing apparatus of a type in which magnetic toner attached to the entire surface of a photoconductor is collected by a bare electrode roller for development, and the toner attached to the photoconductor is sufficiently developed by an AC bias. It is an object of the present invention to provide an electrophotographic apparatus which is capable of stably obtaining a high-resolution and high-quality image by transporting the image to a low image density due to insufficient toner supply. It also provides an excellent electrophotographic apparatus that can be used in high-speed processes.

[0006]

According to the present invention, there is provided an electrostatic latent image holding member which contains and moves a fixed magnet, a magnetic developer, and an opening portion facing the fixed magnet. A developer reservoir for supplying a magnetic developer to the surface of the holding body, and a position provided with a predetermined gap from the surface of the electrostatic latent image holding body,
An electrode roller whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member; and means for applying a voltage for removing the toner in the non-image portion on the electrostatic latent image holding member to the electrode roller. Magnetic field generating means for generating a magnetic field in the circumferential direction of the electrostatic latent image holder at the electrostatic latent image holder surface position,
And an electrophotographic apparatus.

In the present invention, an electrostatic latent image carrier that contains a fixed magnet and moves, a magnetic developer, and a developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image carrier, An electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member, and the electrostatic latent image holding member. And a means for applying a voltage for removing the toner in the non-image area on the body to the electrode roller, wherein the fixed magnet generates a magnetic flux density distribution having a plurality of peaks on the surface of the electrostatic latent image carrier. The electrophotographic apparatus is characterized in that peaks of magnetic flux densities adjacent to each other in the circumferential direction of the electrostatic latent image carrier have mutually opposite polarities.

Furthermore, the present invention is directed to an electrostatic latent image holding member that moves by containing a fixed magnet A, a magnetic developer, and a developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image holding member. And an electrode which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holder, includes a fixed magnet B, and rotates in a traveling direction opposite to the traveling direction of the electrostatic latent image holder. A roller and a means for applying a voltage for removing the toner in the non-image area on the electrostatic latent image carrier to the electrode roller, and the fixed magnet A has a plurality of members on the surface of the electrostatic latent image carrier. A magnetic flux density distribution having a peak is generated, the magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier have opposite polarities, and the magnetic pole A1 on the downstream side of the fixed magnet A in the circumferential direction is the electrode. The magnetic pole B1 of the fixed magnet B inside the roller, the electrostatic latent image holder, and Opposed at a position facing the electrode roller, an electrophotographic apparatus, wherein said magnetic pole A1 and the magnetic pole B1 is a pole of the same polarity.

Furthermore, the present invention comprises an electrostatic latent image carrier that moves by containing a fixed magnet and a magnetic material, and a magnetic developer.
The developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image carrier is installed at a position having a predetermined gap from the surface of the electrostatic latent image carrier, and the traveling direction is the electrostatic latent image carrier. An electrode roller that rotates in a direction opposite to the traveling direction of the image holding member; and a unit that applies a voltage for removing the toner in the non-image portion on the electrostatic latent image holding member to the electrode roller. It is an electrophotographic device that does.

Furthermore, the present invention comprises an electrostatic latent image carrier that contains a fixed magnet and moves, a magnetic developer, and a developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image carrier. An electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member and which rotates in a direction opposite to the moving direction of the electrostatic latent image holding member; Electrophotography characterized by having a means for applying a voltage for removing the toner in the non-image area on the holding body to the electrode roller, and a means for improving the frictional force against the toner on the surface of the electrostatic latent image holding body. It is a device.

Furthermore, the present invention has a surface of the electrostatic latent image holding member, which has an electrostatic latent image holding member which contains a fixed magnet and moves, a magnetic developer, and an opening portion which faces the fixed magnet. Is installed at a position having a predetermined gap with the surface of the electrostatic latent image holder and a developer reservoir for supplying a magnetic developer to the electrostatic latent image holder. A rotating electrode roller, and a means for applying a voltage to the electrode roller to remove toner in the non-image area on the electrostatic latent image carrier,
Magnetic field generating means for generating a magnetic field in the circumferential direction of the electrostatic latent image carrier at the surface position of the electrostatic latent image carrier, and magnetic field generating means for generating a magnetic field in the circumferential direction of the electrode roller at the surface position of the electrode roller. And an electrophotographic apparatus.

Still further, according to the present invention, an electrostatic latent image carrier that contains a fixed magnet A and moves, a magnetic developer, and a developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image carrier. And an electrode which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holder, includes a fixed magnet B, and rotates in a traveling direction opposite to the traveling direction of the electrostatic latent image holder. A roller and a means for applying a voltage for removing the toner in the non-image area on the electrostatic latent image carrier to the electrode roller, and the fixed magnet A has a plurality of members on the surface of the electrostatic latent image carrier. A magnetic flux density distribution having a peak is generated, the magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier have opposite polarities, and the fixed magnet B has a plurality of peaks on the surface of the electrode roller. Generated magnetic flux density distribution Magnetic flux density peaks adjacent to each other have opposite polarities, and the magnetic pole A1 on the downstream side in the circumferential direction of the fixed magnet A and the magnetic pole B1 on the upstream side in the circumferential direction of the fixed magnet inside the electrode roller hold the electrostatic latent image. The magnetic pole A1 and the magnetic pole B1 face each other at a position where the body and the electrode roller face each other.
And are magnetic poles of the same polarity.

Still further, according to the present invention, an electrostatic latent image carrier that contains a fixed magnet A and moves, a magnetic developer, and a developer reservoir for supplying the magnetic developer to the surface of the electrostatic latent image carrier. And is installed at a position having a predetermined gap from the surface of the electrostatic latent image holder, contains a fixed magnet B and a magnetic body, and the traveling direction is opposite to the traveling direction of the electrostatic latent image holder. The electrostatic latent image holding member has a rotating electrode roller and a means for applying a voltage to the electrode roller to remove toner in a non-image area on the electrostatic latent image holding member. Magnetic flux density distribution having a plurality of peaks is generated, and the peaks of the magnetic flux densities adjacent to each other in the circumferential direction of the electrostatic latent image carrier have opposite polarities, and the magnetic pole A1 on the downstream side of the fixed magnet A in the circumferential direction. Is the magnetic pole B1 of the fixed magnet inside the electrode roller
And the electrostatic latent image holding member and the electrode roller face each other at a facing position, the magnetic pole A1 is a magnetic pole having the same polarity as the magnetic pole B1, and is located on the downstream side in the circumferential direction of the fixed magnet B inside the electrode roller. The electrophotographic apparatus is characterized in that the magnetic body is additionally provided.

[0014]

According to the present invention, an electrostatic latent image holder containing a fixed magnet is used, and a developer is sprinkled and magnetically adhered to the electrostatic latent image holder on which an electrostatic latent image is formed, and the electrostatic latent image carrier is carried to the electrode roller portion. This is an improved configuration of an electrophotographic apparatus in which the toner is conveyed, an AC bias is applied to the electrode roller, and the non-image portion toner of the electrostatic latent image holding member is removed by electrostatic force and magnetic force.

In the present invention, the toner supplied to the electrostatic latent image holding member is newly provided with means for supplying and conveying the magnetic developer supplied to the surface of the electrostatic latent image holding member to the developing field. Is sufficiently supplied to the toner, the image quality can be obtained with a high image density even under a high humidity condition where the fluidity of the toner is lowered or in a high speed process. In the present invention, by providing magnetic field generating means for generating a magnetic field in the circumferential direction of the electrostatic latent image holder at the surface position of the electrostatic latent image holder, as shown in FIG. A magnetic brush of toner is formed in the direction, so that the carrying force of the electrostatic latent image carrier is not the individual toner of the first layer directly contacting the surface of the electrostatic latent image carrier, but the entire magnetic brush. Therefore, the toner supply / conveyance ability is remarkably improved, and the conveyance unevenness due to the variation of the frictional force of each toner is eliminated. Therefore, the toner supplied to the electrostatic latent image holding member can be strongly and constantly supplied to the developing field, so that the toner can be supplied with high density even under high humidity conditions or high-speed processes.
It is possible to obtain high image quality without uneven density.

Further, in the present invention, a fixed magnet is provided inside the electrostatic latent image holder so that the polarities of the magnets adjacent to each other in the circumferential direction of the electrostatic latent image holder are opposite to each other. A magnetic field having a plurality of magnetic flux density peaks appears at the surface position of the image carrier, and the toner forms a magnetic brush along the magnetic field. As a result, the direction of the magnetic brush of the toner changes abruptly at the peak of the magnetic flux density on the surface of the electrostatic latent image holder, so that the toner is disturbed and is easily charged due to friction between the electrostatic latent image holder and the toner. . This action not only conveys the toner supplied to the surface of the electrostatic latent image carrier to the developing field but also imparts an electric charge at the same time, so that even under high humidity conditions and high-speed processes, high density and uneven density High image quality that does not occur can be obtained.

Further, in the present invention, a fixed magnet is provided inside the electrode roller, and a magnetic pole of the fixed magnet inside the electrostatic latent image holding member and a fixed magnet inside the electrode roller are provided at a position where the electrostatic latent image holding member faces the electrode roller. By arranging the magnetic poles facing each other so that they have the same polarity as each other, the outlet between the electrostatic latent image holding member and the electrode roller that appears in the opposite polarity configuration at the facing position is blocked as shown in FIG. Since the magnetic brush is not formed and the supply of toner to the developing field and the recovery of toner from the developing field are smooth, even under high humidity conditions or high-speed processes, high density does not occur, and uneven density does not occur. It is possible to obtain a high-quality image without fog or image history.

Further, in the present invention, a part of the magnetic poles of the fixed magnet inside the electrostatic latent image holding member is made of a magnetic material, so that the magnetic force lines can be concentrated more locally than in the case where only the magnet is constituted, and the electrostatic latent The magnetic field appearing on the surface of the image carrier becomes stronger,
The carrying ability and the charging ability can be further improved. Further, the magnetic pole structure of the fixed magnet can be simplified and the cost can be reduced.

Further, in the present invention, the means for improving the frictional force with the toner is provided on the surface of the electrostatic latent image holding member, so that the feeding and conveying force of the toner supplied to the surface of the electrostatic latent image holding member is increased. A high-quality image with high density and high density can be obtained even under high humidity conditions and high-speed processes. The improvement of the frictional force with the toner can be achieved by forming fine grooves on the surface of the electrostatic latent image holding member or by performing a blast treatment. For example, by blasting the surface roughness to Ra 0.5 or more,
The toner supplied to the surface of the electrostatic latent image holder can be more strongly and stably conveyed as the electrostatic latent image holder rotates without slipping.

Further, in the present invention, in addition to the means for supplying and conveying the magnetic developer supplied to the surface of the electrostatic latent image carrier to the developing field, the magnetic developer collected on the surface of the electrode roller is stored in the developer from the developing field. By newly providing a means for collecting and conveying to the developing field, the toner supplied to the surface of the electrostatic latent image carrier is sufficiently supplied and conveyed to the developing field, and the unnecessary toner collected on the surface of the electrode roller in the developing field is not developed. Since the toner is collected and conveyed to the developer reservoir without staying in the developer, it has a feature that a high image density and a high quality image without fog can be obtained even under a high humidity condition where the fluidity of the toner is lowered or a high speed process. According to the present invention, by providing the magnetic field generating means for generating the magnetic field in the circumferential direction of the electrostatic latent image holder at the surface position of the electrostatic latent image holder, the magnetic brush of the toner is moved in the circumferential direction of the electrostatic latent image holder. As a result, the supply-carrying force of the electrostatic latent image holding member acts on the entire magnetic brush, not on each of the first layer toner particles that directly contact the surface of the electrostatic latent image holding member. In addition, the toner supply / conveyance capability is remarkably improved, and the conveyance unevenness due to the variation in the frictional force of each toner is eliminated. Similarly, by providing the magnetic field generating means for generating the magnetic field in the circumferential direction of the electrode roller at the surface position of the electrode roller, the toner collecting and conveying ability is remarkably improved, and the uneven conveyance is also eliminated. Therefore, the toner supplied to the surface of the electrostatic latent image carrier can be strongly and uniformly supplied to the developing field, and the toner collected on the surface of the electrode roller can be quickly removed from the developing field. Even in high-speed processes, high density can be obtained without uneven density and without fog.

Further, in the present invention, a fixed magnet is provided inside the electrostatic latent image holder so that the polarities of the magnets adjacent to each other in the circumferential direction of the electrostatic latent image holder are opposite to each other, and the electrode is provided inside the electrode roller. A fixed magnet is provided such that the magnetic poles of the magnets adjacent to each other in the circumferential direction of the roller have opposite polarities, and the magnetic poles and electrodes of the fixed magnet inside the electrostatic latent image holder are provided at the position where the electrostatic latent image holder and the electrode roller face each other. By arranging the magnetic poles of the fixed magnets inside the roller so that they face each other and have the same polarity as each other, in addition to improving the transporting ability and the charging ability, the electrostatic latent image holding member side and the electrode roller side at the facing position The magnetic fields repel each other, and the magnetic brush that blocks between the electrostatic latent image carrier and the electrode roller is not formed, so the supply and recovery of toner to the developing field is smooth, so even under high humidity conditions and high-speed processes, high concentration is possible. , Uneven density occurs There, and high image quality with no fog and image history is obtained.

Further, in the present invention, a part of the magnetic poles of the fixed magnet inside the electrode roller is made of a magnetic material, so that the magnetic force lines can be concentrated more easily than the case where only the magnet is formed, and the magnetic field appearing on the surface of the electrode roller is stronger. Therefore, the transporting ability and the charging ability can be further improved. Further, since the magnetic field in the circumferential direction of the electrode roller can be locally formed, the magnetic field in the circumferential direction of the electrostatic latent image carrier and the magnetic field for supplying toner from the developer reservoir to the surface of the electrostatic latent image carrier are disturbed. It is possible to form a magnetic field in the circumferential direction of the electrode roller without any influence, and it is possible to improve the recovery / transportation capability without adversely affecting the supply / transportation capability. Further, the magnetic pole structure of the fixed magnet can be simplified and the cost can be reduced.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrophotographic apparatus of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows an embodiment of an electrophotographic apparatus of the present invention. In FIG. 1, 14 is an organic photosensitive drum (diameter 30 mm) in which phthalocyanine is dispersed in a polyester binder resin, which is rotated at a peripheral speed of 30 mm / s. Reference numeral 15 is a two-pole magnet fixed coaxially with the photoconductor 14, 16 is a corona charger for negatively charging the photoconductor 14, 17 is a grid electrode for controlling the charging potential of the photoconductor 14, and 18 is signal light. , 19 are developer reservoirs, 2
0 is a negatively chargeable magnetic one-component toner having an average particle size of about 12 μm. Reference numeral 21 denotes an electrode roller (diameter 16 mm) made of aluminum, which was rotated in the direction opposite to the photoconductor 14 at a peripheral speed of 30 mm / s. Reference numeral 22 is a magnet fixed coaxially with the electrode roller 21, 23 is an AC high voltage power source for applying a voltage to the electrode roller 21, 24 is a scraper made of a polyester film for scraping off the toner on the electrode roller 21, and 25 is on the photoconductor 14. Is a transfer corona charger that transfers the toner image of No. 1 to paper. Two
Reference numeral 6 is a cleaner for cleaning the remaining toner after the toner on the photoconductor 14 is transferred.

FIG. 3 shows the magnetic flux density distribution of the magnet 15 on the surface of the photoconductor 14 in the vertical direction. The peak of magnetic flux density is -70
They are 0 Gs (S pole) and 500 Gs (N pole). Also,
The peak of the magnetic flux density of the magnet 22 on the surface of the electrode roller 21 is 600 GS (N pole). Magnet 15 inside photoconductor 14
The positional relationship between the magnet 22 and the magnet 22 inside the electrode roller 21 is shown in FIG. The angle of the south pole of the magnet 15 inside the photoconductor 14 was set to θ1 = 40 ° upstream from the position facing the electrode roller 21, and the north pole was set to θ2 = 10 °. The angle of the magnet 22 inside the electrode roller 21 is θ3 from the position facing the photoconductor 14 toward the upstream side.
= -15 ° was set. The range of θ1 is 15 ° <θ1
<50 ° is preferable, and the range of 20 ° <θ1 <45 ° is most preferable. θ2 is preferably in the range of 0 ° <θ <30 °, and particularly preferably in the range of 5 ° <θ <20 °. θ3 is preferably in the range of −30 ° <θ <10 °, and particularly preferably in the range of −20 ° <θ <0 °.

The magnetic one-component toner used was composed of 70% polyester resin, 25% ferrite, 3% carbon black, and 2% oxycarboxylic acid metal complex, and 0.4% colloidal silica was added externally. (All were weight%).

The operation of the electrophotographic apparatus configured as described above will be described below with reference to FIG. Photoconductor 1
4 is a corona charger 16 (applied voltage-4 kV, grid 17
Of -500V) was charged to -500V. The photoconductor 14 was irradiated with laser light 18 to form an electrostatic latent image. At this time, the exposure potential (Vr) of the photoconductor 14 is -100.
It was V. On the surface of the photoconductor 14, magnetic one-component toner is attached in the developer reservoir 19 by the magnetic force of the magnet 15 in the photoconductor 14. At this time, the toner is approximately -3 μC / g
Was charged to. Next, the toner attached on the photoconductor 14 forms a magnetic brush along the magnetic field in the circumferential direction of the photoconductor 14 by the magnet 15 inside the photoconductor 14, and the magnetic brush is conveyed by the frictional force due to the rotation of the photoconductor 14. It was Then, the photoconductor 14 having the toner layer attached thereto was passed in front of the electrode roller 21. The electrode roller 21 is made up of the photoconductors 14 and 300.
It was installed with a distance of μm. A high voltage power supply 23 applied to the electrode roller 21 an alternating voltage (frequency: 1 kHz) of 750 V 0-p having a waveform shown in FIG. The toner layer on the photoconductor 14 moves between the photoconductor 14 and the electrode roller 21, so that the toner in the non-image area gradually moves to the electrode roller 21 side, and the toner image on the photoconductor 14 is negative-positive inverted only in the image area. Remained. The toner attached to the electrode roller 21 is conveyed by the rotation in the direction of the arrow,
After scraped off by the scraper 24 and returned to the developer reservoir 19, the electrode roller 21 was used again for the next image formation. It was noted that the toner was violently disturbed above the S pole inside the photoconductor 14. The toner image thus obtained on the photoconductor 14 was transferred onto paper (not shown) by the transfer corona charger 13 and then thermally fixed by a fixing device (not shown). As a result, a sharp image having high image density and no uneven density was obtained. On the other hand, the photoreceptor 1 after transfer
The toner remaining on the sheet 4 is conveyed by the movement of the photoconductor 14 and is collected by the cleaner 14.

(Embodiment 2) The configuration of FIG. 6 is similar to that of FIG.
Magnet 1 fixed inside the photoconductor 14 coaxially with the photoconductor 14.
5 is different from the magnet 15 in that a magnetic plate 27 is added on the upstream side of the magnet 15. FIG. 7 shows the magnetic flux density distribution of the magnet 15 and the magnetic plate 27 on the surface of the photoconductor 14 in the vertical direction. The peaks of the magnetic flux density are -300 Gs (magnetic plate) and 500 Gs (N pole). The positional relationship between the magnet 15 and the magnetic plate 27 inside the photoconductor 14 and the magnet 22 inside the electrode roller 21 is shown in FIG.
The angle of the magnetic plate inside the photoconductor 14 was set to θ1 = 40 ° upstream from the position facing the electrode roller 21, and the N pole of the magnet 15 inside the photoconductor 14 was set to θ2 = 10 °. Electrode roller 2
The north pole of the magnet 22 inside 1 was set at θ3 = −15 ° upstream from the position facing the photoconductor 14. The range of θ1 is preferably 15 ° <θ1 <50 °, particularly 20 ° <θ1 <
The optimum range is 45 °. θ2 is preferably in the range of 0 ° <θ <30 °, and particularly preferably in the range of 5 ° <θ <20 °. θ3 is preferably in the range of −30 ° <θ <10 °,
Particularly, the range of −20 ° <θ <0 ° is optimal.

The operation of the electrophotographic apparatus configured as described above will be described below with reference to FIG. Photoconductor 1
4 is a corona charger 16 (applied voltage-4 kV, grid 17
Of -500V) was charged to -500V. The photoconductor 14 was irradiated with laser light 18 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor 14 was −100V. On the surface of the photoconductor 14, magnetic one-component toner is attached in the developer reservoir 19 by the magnetic force of the magnet 15 in the photoconductor 14. Next, the toner attached on the photoconductor 14 forms a magnetic brush along the magnetic field in the circumferential direction of the photoconductor 14 by the magnet 15 inside the photoconductor 14, and the magnetic brush is conveyed by the frictional force due to the rotation of the photoconductor 14. It was Then, the photoconductor 14 having the toner layer attached thereto was passed in front of the electrode roller 21. A high voltage power supply 23 is used for the electrode roller 21 to generate a waveform shown in FIG.
An alternating voltage of p (frequency 1 kHz) was applied. The toner layer on the photoconductor 14 moves between the photoconductor 14 and the electrode roller 21, so that the toner in the non-image area gradually moves to the electrode roller 21 side, and the toner image on the photoconductor 14 is negative-positive inverted only in the image area. Remained. The toner adhering to the electrode roller 21 forms a magnetic brush along the magnetic field in the electrode roller circumferential direction by the magnet 22 inside the electrode roller, and is conveyed together with the magnetic brush by the frictional force due to the rotation of the electrode roller 21, and is scraped by the scraper 24. After scraped off and returned to the developer reservoir 19, the electrode roller 21 was used again for the next image formation. In addition,
It was observed that the toner was violently disturbed above the magnetic plate 27 in the photoconductor 14. The toner image thus obtained on the photoconductor 14 was transferred onto paper (not shown) by the transfer corona charger 25, and then thermally fixed by a fixing device (not shown). As a result, it was possible to obtain a sharp image with high image density and no unevenness in density and no fog or image history. On the other hand, the toner remaining on the photoconductor 14 after the transfer is conveyed by the movement of the photoconductor 14 and is collected by the cleaner 26.

(Embodiment 3) The configuration of FIG. 9 is similar to that of FIG.
The magnet 22 fixed coaxially with the electrode roller 21 inside the electrode roller 21 is different. FIG. 10 shows a vertical magnetic flux density distribution on the surface of the electrode roller 21 of the magnet 22. The peak of magnetic flux density is 600Gs (N pole) and -300Gs (S pole)
Is. The positional relationship between the magnet 15 inside the photoconductor 14 and the magnet 22 inside the electrode roller 21 is shown in FIG. Photoconductor 14
The angle of the south pole of the internal magnet 15 was set to θ1 = 40 ° upstream from the position facing the electrode roller 21, and the north pole was set to θ2 = 10 °. The N pole of the magnet 22 inside the electrode roller 21 was set to θ3 = −15 ° upstream from the position facing the photoconductor 14, and the S pole was set to θ4 = 20 °. The range of θ1 is 15 ° <
θ1 <50 ° is preferable, and the range of 20 ° <θ1 <45 ° is most preferable. θ2 is preferably in the range of 0 ° <θ <30 °, and particularly preferably in the range of 5 ° <θ <20 °. θ
3 is preferably in the range of −30 ° <θ <10 °, particularly −2.
The range of 0 ° <θ <0 ° is optimal. θ4 is 0 ° <θ <
The range of 30 ° is preferable, and the range of 5 ° <θ <25 ° is most preferable.

The operation of the electrophotographic apparatus configured as described above will be described below with reference to FIG. Photoconductor 1
4 is a corona charger 16 (applied voltage-4 kV, grid 17
Of -500V) was charged to -500V. The photoconductor 14 was irradiated with laser light 18 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor 14 was −100V. On the surface of the photoconductor 14, magnetic one-component toner is attached in the developer reservoir 19 by the magnetic force of the magnet 15 in the photoconductor 14. Next, the toner attached on the photoconductor 14 forms a magnetic brush along the magnetic field in the circumferential direction of the photoconductor 14 by the magnet 15 inside the photoconductor 14, and the magnetic brush is conveyed by the frictional force due to the rotation of the photoconductor 14. It was Then, the photoconductor 14 having the toner layer attached thereto was passed in front of the electrode roller 21. A high voltage power supply 23 is used for the electrode roller 21 to generate a waveform shown in FIG.
An alternating voltage of p (frequency 1 kHz) was applied. The toner layer on the photoconductor 14 moves between the photoconductor 14 and the electrode roller 21, so that the toner in the non-image area gradually moves to the electrode roller 21 side, and the toner image on the photoconductor 14 is negative-positive inverted only in the image area. Remained. The toner adhering to the electrode roller 21 forms a magnetic brush along the magnetic field in the electrode roller circumferential direction by the magnet 22 inside the electrode roller, and is conveyed together with the magnetic brush by the frictional force due to the rotation of the electrode roller 21, and is scraped by the scraper 24. After scraped off and returned to the developer reservoir 19, the electrode roller 21 was used again for the next image formation. In addition,
The upper part of the S pole inside the photoconductor 14 and the S inside the electrode roller 21
It was seen that the toner was violently disturbed at the top of the pole. The toner image thus obtained on the photoconductor 14 is
After being transferred onto paper (not shown) by the transfer corona charger 25, it was thermally fixed by a fixing device (not shown). As a result, it was possible to obtain a sharp image with high image density and no unevenness in density and no fog or image history. On the other hand, the toner remaining on the photoconductor 14 after the transfer is conveyed by the movement of the photoconductor 14 and is collected by the cleaner 26.

(Embodiment 4) The structure of FIG. 12 differs from the structure of FIG. 1 in that a magnetic plate 27 is provided above the magnet 22 fixed coaxially with the electrode roller 21 inside the electrode roller 21. FIG. 13 shows a vertical magnetic flux density distribution of the magnet 22 on the surface of the electrode roller 21. The peak of magnetic flux density is 600G
s (N pole) and -200 Gs (magnetic plate). The positional relationship between the magnet 15 inside the photoconductor 14 and the magnet 22 inside the electrode roller 21 is shown in FIG. Magnet 15 inside photoconductor 14
The angle of the S pole was set to θ1 = 40 ° upstream from the position facing the electrode roller 21, and the angle of the N pole was set to θ2 = 10 °. The north pole of the magnet 22 inside the electrode roller 21 is θ3 = −15 ° upstream from the position facing the photoconductor 14, and the magnetic plate is θ4 = 15 °.
Set to °. The range of θ1 is preferably 15 ° <θ1 <50 °, and particularly preferably the range of 20 ° <θ1 <45 °. θ2 is preferably in the range of 0 ° <θ <30 °, and particularly preferably in the range of 5 ° <θ <20 °. θ3 is preferably in the range of −30 ° <θ <10 °, particularly −20 ° <θ <0.
The range of ° is optimal. θ4 is preferably in the range of 0 ° <θ <30 °, and particularly preferably in the range of 5 ° <θ <25 °.

The operation of the electrophotographic apparatus configured as described above will be described below with reference to FIG. The photoconductor 14 is a corona charger 16 (applied voltage-4 kV, grid 1
The battery was charged to -500V with a voltage of 7 (-500V). The photoconductor 14 was irradiated with laser light 18 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor 14 was −100V. On the surface of the photoconductor 14, magnetic one-component toner is attached in the developer reservoir 19 by the magnetic force of the magnet 15 in the photoconductor 14. Next, the toner attached on the photoconductor 14 forms a magnetic brush along the magnetic field in the circumferential direction of the photoconductor 14 by the magnet 15 inside the photoconductor 14, and the magnetic brush is conveyed by the frictional force due to the rotation of the photoconductor 14. It was Then, the photoconductor 14 having the toner layer attached thereto was passed in front of the electrode roller 21. A high voltage power supply 23 is used for the electrode roller 21 to generate a waveform shown in FIG.
An alternating voltage of p (frequency 1 kHz) was applied. The toner layer on the photoconductor 14 moves between the photoconductor 14 and the electrode roller 21, so that the toner in the non-image area gradually moves to the electrode roller 21 side, and the toner image on the photoconductor 14 is negative-positive inverted only in the image area. Remained. The toner adhering to the electrode roller 21 forms a magnetic brush along the magnetic field in the electrode roller circumferential direction by the magnet 22 inside the electrode roller, and is conveyed together with the magnetic brush by the frictional force due to the rotation of the electrode roller 21, and is scraped by the scraper 24. After scraped off and returned to the developer reservoir 19, the electrode roller 21 was used again for the next image formation. In addition,
It was found that the toner was violently disturbed above the S pole inside the photoconductor 14 and above the magnetic plate inside the electrode roller 21. The toner image thus obtained on the photoconductor 14 was transferred onto paper (not shown) by the transfer corona charger 25, and then thermally fixed by a fixing device (not shown). As a result, it was possible to obtain a sharp image with high image density and no unevenness in density and no fog or image history. On the other hand, the toner remaining on the photoconductor 14 after the transfer is conveyed by the movement of the photoconductor 14 and is collected by the cleaner 26.

(Embodiment 5) Next, an embodiment at a high print speed will be described. Figure 15 shows a process speed of 180m
The magnet 15 inside the photoconductor 14 is different from that of FIG. Another difference is that the surface of the photoconductor 14 is blasted to Ra 0.8.
The operation of the electrophotographic apparatus configured as described above will be described below with reference to FIG. The photoconductor 14 is connected to a corona charger 16 (applied voltage −6 kV, grid 17 voltage −5).
00V) and charged to -500V. This photoconductor 14
Laser light 18 was irradiated on the surface to form an electrostatic latent image. At this time, the exposure potential of the photoconductor 14 was −100V. On the surface of the photoconductor 14, magnetic one-component toner is attached in the developer reservoir 19 by the magnetic force of the magnet 15 in the photoconductor 14. The toner adhering to the photoconductor 14 is conveyed by the groove on the surface of the photoconductor 14 without receiving a strong frictional force, and the photoconductor 14 having the toner layer adhered thereto is passed in front of the electrode roller 21. . By the high voltage power supply 23 to the electrode roller 21,
7 superimposed with a DC voltage of -300V of the waveform shown in FIG.
An alternating voltage of 50 V0-p (frequency 3 kHz) was applied. The toner layer on the photoconductor 14 moves between the photoconductor 14 and the electrode roller 21, so that the toner in the non-image area gradually moves to the electrode roller 21 side, and the toner image on the photoconductor 14 is negative-positive inverted only in the image area. Remained. The toner adhered on the electrode roller 21 is conveyed by the rotation in the direction of the arrow, and the scraper 24
It was scraped off by scraping, returned to the developer reservoir 19 again, and used for the next image formation. The toner image thus obtained on the photoconductor 14 was transferred onto paper (not shown) by the transfer corona charger 25, and then thermally fixed by a fixing device (not shown).
As a result, a sharp image with high density and no uneven density was obtained. On the other hand, the toner remaining on the photoconductor 14 after the transfer was conveyed by the movement of the photoconductor 14 and was collected by the cleaner 26.

In the present embodiment, the surface of the photoconductor 14 was blast-processed, but even if fine grooves were provided on the surface of the photoconductor 14, the frictional force of the surface of the photoconductor 14 with respect to the toner was remarkably improved. Since the toner is transported without slipping, a sharp image with high density and no uneven density was obtained.

[0036]

According to the present invention, it is possible to obtain an excellent electrophotographic apparatus having a simple structure, high image quality, and high speed processing.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electrophotographic apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram for explaining the function and effect of the present invention.

FIG. 3 is a vertical magnetic flux density distribution diagram on the surface of the photoconductor in the first embodiment of the present invention.

FIG. 4 is an enlarged view for explaining the magnetic pole arrangement according to the first embodiment of the present invention.

FIG. 5 is a schematic diagram showing a waveform of an AC voltage used in the first, second, third, fourth and fifth embodiments of the present invention.

FIG. 6 is a configuration diagram of an electrophotographic apparatus according to a second embodiment of the present invention.

FIG. 7 is a vertical magnetic flux density distribution diagram on the surface of the photoconductor in the second embodiment of the present invention.

FIG. 8 is an enlarged view illustrating a magnetic pole arrangement according to a second embodiment of the present invention.

FIG. 9 is a block diagram of an electrophotographic apparatus according to a third embodiment of the present invention.

FIG. 10 is a vertical magnetic flux density distribution diagram on the surface of the electrode roller according to the third embodiment of the present invention.

FIG. 11 is an enlarged view illustrating a magnetic pole arrangement according to a third embodiment of the present invention.

FIG. 12 is a block diagram of an electrophotographic apparatus according to a fourth embodiment of the present invention.

FIG. 13 is a magnetic flux density distribution diagram in the vertical direction on the surface of the electrode roller according to the fourth embodiment of the present invention.

FIG. 14 is an enlarged view illustrating a magnetic pole arrangement according to a fourth embodiment of the present invention.

FIG. 15 is a block diagram of an electrophotographic apparatus according to a fifth embodiment of the present invention.

FIG. 16 is a block diagram of a conventional electrophotographic developing device.

[Explanation of symbols]

 1.14 Photoreceptor 2.15 Magnet 3.16 Corona charger 4.17 Grid electrode 5.18 Laser exposure 6.19 Developer reservoir 7.20 Magnetic developer 8 Damper 9.21 Electrode roller 10.22 Magnet 11. 23 AC high-voltage power supply 12/24 Scraper 13-25 Transfer corona charger 26 Cleaner 27 Magnetic plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuma Hayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Masahiro Aizawa 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (14)

[Claims] 1. An electrostatic latent image holding member, and magnetic field generating means for generating a magnetic field in a circumferential direction of the electrostatic latent image holding member at a surface position of the electrostatic latent image holding member. A fixed magnet fixed inside the holding member, a magnetic developer, and a developer reservoir having an opening facing the fixed magnet and supplying the magnetic developer to the surface of the electrostatic latent image holding member; An electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holder, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holder, and the electrostatic latent image holder. Means for applying a voltage for removing the toner in the non-image area on the electrode roller;
An electrophotographic apparatus comprising: 2. An electrostatic latent image carrier, and a plurality of magnetic flux density peaks at the surface position of the electrostatic latent image carrier, and magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier. A fixed magnet that is fixed inside the electrostatic latent image carrier to generate magnetic flux density distributions having opposite polarities, a magnetic developer, and the magnetic developer are supplied to the surface of the electrostatic latent image carrier. A developer reservoir, an electrode roller installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member, and rotating in a direction opposite to the moving direction of the electrostatic latent image holding member; An electrophotographic apparatus, comprising: a unit that applies a voltage for removing toner in a non-image area on the electrostatic latent image carrier to the electrode roller. 3. An electrostatic latent image carrier and a plurality of magnetic flux density peaks at the surface position of the electrostatic latent image carrier, and magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier. Supplying a fixed magnet A fixed inside the electrostatic latent image carrier, a magnetic developer, and a magnetic developer to the surface of the electrostatic latent image carrier, which generate magnetic flux density distributions having mutually opposite polarities. A developer reservoir, and an electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member, A magnetic pole A1 on the downstream side in the circumferential direction of the fixed magnet A faces the magnetic pole B1 of the fixed magnet inside the electrode roller at a position where the electrostatic latent image holding member and the electrode roller face each other, and the magnetic pole B1.
A fixed magnet B fixed inside the electrode roller 1 having the same polarity as the magnetic pole A1 and a voltage for removing the toner in the non-image area on the electrostatic latent image carrier are applied to the electrode roller. And an electrophotographic apparatus. 4. An electrostatic latent image holding member, a fixed magnet and a magnetic member fixed inside the electrostatic latent image holding member, a magnetic developer, and the magnetic development on the surface of the electrostatic latent image holding member. An electrode which is installed at a position having a predetermined gap from the developer reservoir for supplying the agent and the surface of the electrostatic latent image holding member, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member. An electrophotographic apparatus comprising: a roller; and a means for applying a voltage for removing toner in a non-image area on the electrostatic latent image carrier to the electrode roller. 5. A fixed magnet and a magnetic body generate a magnetic flux density distribution having a plurality of peaks at a surface position of the electrostatic latent image carrier, and two magnetic flux densities adjacent to each other in the circumferential direction of the electrostatic latent image carrier. 5. The electrophotographic apparatus according to claim 4, wherein the peaks of the two have opposite polarities. 6. An electrostatic latent image holding member having a means for improving a frictional force with respect to toner on a surface thereof, a fixed magnet fixed inside the electrostatic latent image holding member, a magnetic developer, and the electrostatic latent image holding member. The developer reservoir for supplying the magnetic developer to the surface of the image carrier and the surface of the electrostatic latent image carrier are installed at a position having a predetermined gap, and the traveling direction of the electrostatic latent image carrier is An electrophotographic apparatus comprising: an electrode roller that rotates in a direction opposite to a traveling direction; and a unit that applies a voltage for removing toner in a non-image portion on the electrostatic latent image holding member to the electrode roller. . 7. The electrophotographic apparatus according to claim 6, wherein fine grooves are formed on the surface of the electrostatic latent image holding member. 8. The electrophotographic apparatus according to claim 6, wherein the surface of the electrostatic latent image holding member is a rough surface having a Ra of 0.5 μm or more. 9. An electrostatic latent image holding member, and magnetic field generating means for generating a magnetic field in the circumferential direction of the electrostatic latent image holding member at the surface position of the electrostatic latent image holding member. A fixed magnet fixed inside the holding member, a magnetic developer, and a developer reservoir having an opening facing the fixed magnet and supplying the magnetic developer to the surface of the electrostatic latent image holding member; An electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member; Magnetic field generating means for generating a magnetic field in the circumferential direction of the electrode roller,
And a means for applying a voltage for removing the toner in the non-image area on the electrostatic latent image carrier to the electrode roller. 10. An electrostatic latent image carrier and a plurality of magnetic flux density peaks at the surface position of the electrostatic latent image carrier, and magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier. Supplying a fixed magnet A fixed inside the electrostatic latent image carrier, a magnetic developer, and a magnetic developer to the surface of the electrostatic latent image carrier, which generate magnetic flux density distributions having mutually opposite polarities. A developer reservoir, and an electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member,
The electrode roller has a plurality of magnetic flux density peaks at the surface position, and the magnetic flux density peaks adjacent to each other in the circumferential direction of the electrode roller generate a magnetic flux density distribution having opposite polarities, and the fixed magnet A has a circumferential direction. Magnetic pole A1 on the downstream side and magnetic pole B on the upstream side in the circumferential direction of the fixed magnet inside the electrode roller.
A fixed magnet B fixed inside the electrode roller, the magnetic pole B1 being a magnetic pole having the same polarity as the magnetic pole A1; An electrophotographic apparatus, comprising: a unit that applies a voltage for removing toner in a non-image area on the electrostatic latent image carrier to the electrode roller. 11. The electrophotographic apparatus according to claim 10, further comprising a magnetic body fixed inside the electrostatic latent image holder. 12. An electrostatic latent image carrier, and a plurality of magnetic flux density peaks at the surface position of the electrostatic latent image carrier, and magnetic flux density peaks adjacent to each other in the circumferential direction of the electrostatic latent image carrier. Supplying a fixed magnet A fixed inside the electrostatic latent image carrier, a magnetic developer, and a magnetic developer to the surface of the electrostatic latent image carrier, which generate magnetic flux density distributions having mutually opposite polarities. A developer reservoir, and an electrode roller which is installed at a position having a predetermined gap from the surface of the electrostatic latent image holding member, and whose traveling direction rotates in a direction opposite to the traveling direction of the electrostatic latent image holding member,
A magnetic pole A1 on the downstream side in the circumferential direction of the fixed magnet A faces the magnetic pole B1 of the fixed magnet inside the electrode roller at the position where the electrostatic latent image holding member and the electrode roller face each other, and the magnetic pole B1 is the magnetic pole A1. A fixed magnet B fixed inside the electrode roller, which is a magnetic pole having the same polarity as the magnetic pole, a magnetic body attached downstream of the fixed magnet B inside the electrode roller in the circumferential direction, and on the electrostatic latent image holder. An electrophotographic apparatus comprising: a unit that applies a voltage for removing toner in a non-image area to the electrode roller. 13. The fixed magnet B and the magnetic body generate a magnetic flux density distribution having a plurality of peaks at the surface position of the electrode roller, and two magnetic flux density peaks adjacent in the circumferential direction of the electrode roller have opposite polarities. The electrophotographic apparatus according to claim 12, wherein the electrophotographic apparatus is provided. 14. The electrophotographic apparatus according to claim 12, further comprising a magnetic body fixed inside the electrostatic latent image holder.