JPH08123218A - Image forming device and image forming method - Google Patents

Abstract

PURPOSE: To prevent irregularities in an image at the time of transfer in an image forming device which forms an image by using conductive toner. CONSTITUTION: A toner carrier 11 is constituted of a light transmissive conductive base substance 11b and a photoconductive layer 11a. A sleeve 13a internally provided with a fixed magnet 13b is rotated in a direction shown by an arrow R13, and voltage is impressed thereon by a power source 16. Simultaneously, exposure L2 is performed by an exposure device 17 from the inside of the toner carrier 11 toward a toner amount regulating area A1 . Negative charge is injected in the conductive toner T, which is carried and fed to a developing area A2 by the rotation of the toner carrier 11 in a direction shown by an arrow R11. The voltage for the developing area A2 is impressed between the toner carrier 11 and a counter electrode 30, and simultaneously the image-exposure L2 is performed by the exposure device 19 from the inside of the toner carrier 11. Positive charge is injected in the toner T on the toner carrier 11, which flies by electric field and adheres to the surface of a transfer material P, thereby forming the image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus, such as a copying machine or a laser beam printer, which forms an image by attaching a conductive toner onto a transfer material.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic image forming method, US Pat.
As described in Japanese Patent Publication No. 23910, Japanese Patent Publication No. 43-24748, etc., a number of methods are known, but generally a recording material such as a photoconductor made of a photoconductive substance. Was used to form an electrical latent image (hereinafter referred to as "electrostatic latent image") on this recording medium by various means, and then this electrostatic latent image was visualized (developed) with toner to obtain the image. If necessary, the toner image on the recording medium is transferred to a transfer material such as paper, and then the toner image is heated or fixed on the transfer material by solvent vapor or the like to obtain a copied image.

Various methods for developing an electrostatic latent image with toner (developing method) are also known. For example, a magnetic brush developing method described in U.S. Pat. No. 2,870,403, a powder cloud method described in U.S. Pat. No. 2,217,76, and a fur brush developing method,
Many developing methods such as liquid developing methods are known.

Among these developing methods, the magnetic brush method using a two-component developer mainly composed of toner and carrier has been widely put into practical use. This method is an excellent method that can obtain a relatively stable and good image, but on the other hand, deterioration of the carrier and fluctuation of the mixing ratio of the toner and the carrier
It has an unavoidable defect due to the fact that the developer is a two component.

In order to avoid such drawbacks, various developing methods using a one-component developer mainly containing toner (without carrier) have been proposed. For example, US Pat. No. 3,909,258 proposes a method of developing using a magnetic toner having electrical conductivity.
In this method, a conductive magnetic toner is carried on the surface of a cylindrical conductive sleeve having a magnetic substance inside, and the toner is brought into contact with the electrostatic latent image on the recording medium to develop the toner.
At this time, in the developing section, a conductive path is formed between the surface of the sleeve and the surface of the recording medium by the toner particles, and electric charges are guided from the sleeve to the toner particles through the conductive path. Then, the toner particles into which the charges have been injected are attached to the electrostatic latent image by the Coulomb force acting between the toner particles and the electrostatic latent image, and develop the toner particles.

[0006]

However, the developing method using the above-mentioned conductive magnetic toner is excellent in that the problems associated with the conventional two-component developing method can be avoided. Since it is electrically conductive, it has a drawback that it is difficult to electrostatically transfer an image developed on a recording material from the recording material to a final transfer material such as plain paper. That is, when electric and electrostatic transfer techniques are used as the transfer technique, charge exchange occurs between the conductive toner and the surface of the transfer material due to the conductivity of the toner particles described above, which results in conductivity. There is a problem in that the suction force of the transfer material acting on the toner is reduced and the transferred image is disturbed.

In order to solve the above-mentioned transfer problem, a contact transfer system in which a conductive toner is brought into contact with a transfer material to directly form an image on the transfer material is often used. In the contact transfer method, it is necessary to control the contact pressure of the conductive toner layer to the transfer material. If this control is not performed well, toner fusion to the transfer material, fogging,
There were various problems such as poor reproducibility at high contrast.

Therefore, the present invention provides an image forming apparatus and an image forming method for transferring a conductive toner onto a transfer material in a non-contact state while preventing the transfer image from being disturbed. It is intended.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an image forming apparatus for forming an image on a transfer material using a developer containing a toner having conductivity. A toner carrier having a light-transmissive conductive substrate and a light-transmissive photoconductive layer formed on the surface of the conductive substrate, and carrying the toner on the surface on the photoconductive layer side;
A toner regulating member which is arranged so as to face the photoconductive layer of the toner carrier and regulates the thickness of the toner layer on the photoconductive layer, and a voltage is applied between the toner regulating member and the toner carrier. A first power source, and a first exposure device that exposes the photoconductive layer from the back surface side of the conductive base in a toner amount control region formed between the toner control member and the toner carrier. Between the counter electrode arranged facing the photoconductive layer on the downstream side of the toner amount regulation region in the moving direction of the photoconductive layer of the toner carrier, and between the counter electrode and the toner carrier. Image exposure of the photoconductive layer from the back surface side of the conductive substrate according to an electric signal in a developing area formed between a second power source for applying a voltage and the counter electrode and the toner carrier. And a second exposure device for controlling the surface of the toner carrier. Of toner, the toner of the portion corresponding to the image exposure of the second exposure apparatus, characterized in that it is attached to the transfer material supplied to the developing region.

In this case, the surface of the transfer material supplied to the developing region and the toner on the toner carrying member are kept in non-contact with each other in the gap between the counter electrode and the toner carrying member in the developing region. Should be set as follows.

Further, the counter electrode may have a resistance layer having a resistance higher than that of the toner between the counter electrode and the transfer material in the developing area.

Further, in an image forming method for forming an image on a transfer material by using a developer containing a conductive toner, a toner carrier having a light-transmissive conductive substrate and a light-transmissive photoconductive layer. The toner is carried on the surface of the photoconductive layer side of the body, and the layer thickness of the toner layer on the photoconductive layer is regulated in the toner amount regulation region formed by facing the toner regulation member to the toner carrier. Then, a voltage is applied to the toner amount regulation region to charge the toner on the toner carrier, and the photoconductive layer is exposed from the back surface side of the conductive substrate in the toner amount regulation region, The photoconductive layer is electrically removed from the back surface side of the conductive substrate in a developing area formed by facing a counter electrode to the toner carrier on the downstream side of the toner amount regulation area in the moving direction of the photoconductive layer. Image exposure according to the signal, Serial voltage is applied to the developing area,
The toner on the toner carrier is transferred to and adhered to a transfer material inserted into the developing area.

In this case, it is preferable that the transfer material is inserted into the developing area in a non-contact state with the toner on the toner carrier.

[0014]

Before the operation is described, its principle will be briefly described.

According to a study made by the applicant of the present invention, when conductive particles are applied to one electrode of a parallel plate electrode and a voltage equal to or higher than a predetermined voltage between the parallel plate electrodes is applied, the conductivity in contact with the electrode is reduced. It was found that charges are injected into the conductive particles and fly to the counter electrode due to electrostatic force. Further, when the flying conductive particles are contacted with the counter electrode, electric charges are injected again from the electrodes, and this time, the flying particles fly in the opposite direction, and as a result, reciprocating flight motion occurs between the parallel plate electrodes. Was found.

In the parallel plate electrode described above, an electrode not coated with conductive particles is covered with a high-resistance member in contrast to a normal conductive electrode coated with conductive particles, and the coated electrode is When a voltage equal to or higher than a predetermined voltage between parallel plate electrodes is applied, electric charges are injected into the conductive particles in contact with the conductive electrodes, and the particles fly to the counter electrode due to electrostatic force, and It has been found that when the conductive particles come into contact with the coated electrode, no charge is injected and the particles adhere electrostatically to the coated electrode.

The Applicants utilized the above-mentioned phenomenon in order to achieve the object of the present invention. In other words, in the toner amount regulation area formed between the toner regulation member and the toner carrier, while applying a predetermined voltage between the toner regulation member and the toner carrier, the toner carrier surface of the toner carrier is When the photoconductive substrate is exposed from a different surface (the back surface side of the conductive substrate), the conductive toner is charged by induction charging and is coated in a thin layer on the toner carrier. The toner carrier surface of the carrier is also charged by induction charging to a predetermined value according to the applied voltage.

Next, in the developing region formed between the toner carrier and the counter electrode, while applying a voltage of the same polarity as the charged conductive toner on the toner carrier to the counter electrode, the conductive substrate Image exposure is performed on the toner carrier from the back side with light according to an electric signal.

By this image exposure, the charging potential of the portion corresponding to the exposed portion on the toner carrying member is lowered, and a potential difference is generated between the exposed portion on the toner carrying member and the counter electrode, so that the toner carrying member is exposed. The electric charges are re-injected into the toner carried on the exposed portion of the sheet by induction charging. As a result, due to the above-described flying phenomenon, the electrically-conductive toner in which the electric charges are re-injected flies toward the counter electrode.

In the developing area, the flying conductive toner flies onto the transfer material arranged in a non-contact state with the toner carrier to form an image.

That is, according to the method described above, a toner image can be formed on the transfer material while the conductive toner on the toner carrier and the transfer material are kept in a non-contact state.

Further, by providing an area having substantially higher resistance than the conductive toner in the developing area between the transfer material and the counter electrode, the toner image on the transfer material generated by the induced charge from the counter electrode. Disturbance can be prevented.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a longitudinal sectional view showing a schematic configuration of an embodiment of an image forming apparatus according to the present invention. The image forming apparatus shown in the figure includes a developing device 10 (located on the right side in the figure),
The developing device 10 is provided with a counter electrode 30 (on the left side in the drawing) arranged to face the developing device 10. In the developing device 10 described above, a developer having a conductive magnetic toner T (hereinafter simply referred to as “toner T”) as a main component is housed in the developing container 14.

The developing device 10 includes a toner carrier 11 facing the counter electrode 30.

The toner carrier 11 is constructed by laminating a photoconductive layer 11a, which is conductive when irradiated with light, on the surface of a conductive conductive substrate 11b formed in a cylindrical shape. Both the conductive substrate 11b and the photoconductive layer 11a are transparent to light. That is, it is composed of a transparent member. The toner carrier 11 is arranged so as to face the counter electrode 30 arranged on the left side in a non-contact state, and is supported rotatably in the direction of arrow R11.

An arrow R12 is provided diagonally above the toner carrier 11 to convey the toner T toward the toner carrier 11.
A developer carrying member 12 rotatably supported in the direction is arranged, and a toner regulating means 13 is arranged above the toner carrier 11.

The toner regulating means 13 is made of a non-magnetic member and is rotatable in the direction of arrow R13.
a and a fixed magnet 13 arranged in this sleeve 13a
and b. Further, in order to scrape off the toner T from the toner regulating means 13, the scraper 15 made of a magnetic member is provided with a fixed magnet 13b in the sleeve 13a.
It is arranged so as to face one of the magnetic poles and is close to the surface of the sleeve 13a. A power supply 16 for applying a voltage (a negative potential V ₁ in this embodiment) between the toner regulating means 13 and the toner carrier 11 is connected to the toner regulating means 13.

Further, inside the toner carrier 11, 2
Individual exposure devices 17 and 19 are arranged. Exposure device 1
Reference numeral 7 denotes an electric signal from the inside of the toner carrier 11 (the back surface side of the conductive substrate 11b) with respect to the toner amount regulation area A ₁ formed between the surface of the toner carrier 11 and the surface of the toner regulation means 13. Exposure L ₁ is performed based on the above. That is, the light emitted from the inner exposure device 17 is emitted from the toner carrier 1.
1 is transmitted through the conductive substrate 11b, and reaches the photoconductive layer 11a located in the toner amount regulation area A ₁ described above. The gap between the surface of the toner carrier 11 and the surface of the toner regulating means 13 in the toner amount regulation region A ₁ is set to, for example, 300 μm. Then, the voltage V ₁ applied to the toner regulating member 11 by the power supply 16 is set to −300 to −700V. It should be noted that the absolute value of this voltage V ₁ is preferably as large as possible so that leakage does not occur, and is set to −500 V in this embodiment.

On the other hand, the exposure device 19 includes the toner carrier 11
Development area A formed between the surface and the surface of the counter electrode 30
Against ₂ performs image exposure L ₂ based on the electric signal from the inside of the toner carrying member 11. That is, the inner exposure apparatus 1
It is configured that the light emitted from 9 passes through the conductive substrate 11b of the toner carrier 11 and reaches the photoconductive layer 11a located in the outer development area A ₂ .

In cooperation with the toner carrier 11, the development area A ₂
The counter electrode 30 constituting the above is arranged rotatably in the direction of arrow R30 in a state of not contacting the surface of the toner carrier 11. A power supply 3 for charging the surface of the counter electrode 30 to the same polarity as the charging polarity of the toner T held on the toner carrier 11 (negative potential V ₂ in this embodiment).
1 is connected. The gap between the surface of the toner carrier 11 and the surface of the counter electrode 30 in the developing area A ₂ is set to, for example, 500 μm. And power supply 3
1, the voltage V ₂ applied to the counter electrode 30 is set to -500.
Set to -1500V. The absolute value of the voltage V ₂ is preferably as large as the voltage V ₁ toner so long as no leak occurs. In this embodiment, it is set to -1000V.

Next, the operation of the image forming apparatus having the above configuration will be described.

The conductive and magnetic toner T conveyed toward the toner carrier 11 by the developer conveying member 12.
Is conveyed toward the toner amount regulation area A ₁ as the toner carrier 11 rotates in the direction of arrow R11.

In the toner amount regulation area A ₁ , the toner T
Is held in contact with both the toner regulating means 13 and the toner carrier 11 by the magnetic field created by the magnetic pole S of the fixed magnet 13b of the toner regulating means 13.

Here, the toner amount regulation according to this embodiment is performed by the following steps.

That is, in the toner amount regulation area A ₁ , almost simultaneously with the voltage V ₁ being applied between the toner regulation means 13 and the toner carrier 11 by the power supply 16,
The exposure device 17 arranged inside the toner carrier 11 exposes the entire surface of the toner carrier region of the toner carrier 11 to light L ₁ from the inside. The resistance of the photoconductive layer 11a is lowered by the process of this exposure L ₁ , and a current flows between the toner regulating means 13 and the toner carrier 11 via the toner T by the above voltage application. Further, a current also flows in the photoconductive layer 11a by the above-mentioned simultaneous application of the exposure voltage. As a result, charges are injected into the surface of the photoconductive layer 11a, the surface of the photoconductive layer 11a exhibits a certain predetermined charging potential V ₁ depending on the applied voltage, and the toner T in contact with the surface of the photoconductive layer 11a. Also, a charge having a polarity opposite to the polarity of the charge injected to the surface of the photoconductive layer 11a (negative charge in this embodiment) is injected.

Further, in the toner amount regulation area A ₁ , the rotation of the sleeve 13a of the toner regulation means 13 gives a conveying force to the toner T toward the developing container 14, and the toner T into which the electric charge has been injected. Is an electrostatic attractive force between the toner carrier 11 and the toner carrier 11 due to the injection charge.
By the rotation in the direction of arrow R11, a carrying force toward the developing area A ₂ between the toner carrier 11 and the counter electrode 30 is further applied.

Therefore, by the above-mentioned steps, only the injected toner T is coated in a thin layer on the toner carrier 11 and is conveyed toward the developing area A ₂ .

In the developing area A ₂ , the toner carrier 1
1 and the counter electrode 30 between the transfer material P and the toner carrier 11
Is supplied in the direction of arrow K in a non-contact state with respect to
A voltage of negative potential V ₂ is applied to the counter electrode 30 by a power source 31 so as to have the same polarity as the charging polarity of the toner T carried on the surface of the toner carrier 11.

In this embodiment, the developing process for the transfer material P is performed as follows.

The toner T conveyed to the developing area A ₂ is
Image exposure L ₂ according to an electric signal is performed from the inside of the toner carrier 11 by the exposure device 19, and the resistance of the photoconductive layer 11a in the illuminated bright region is lowered. Then, the charged charges of the photoconductive layer 11a and the negative charges of the toner T, which were previously given by the injected charges in the toner amount regulation area A ₁ , disappear through the grounded toner carrier 11 and the counter electrode 30 and the toner carrier are carried. Due to the potential difference between the surface of the body 11 and the surface of the body 11, a charge having a polarity opposite to the charge polarity of the toner T held in the dark area is applied to the toner T by injection charging again.

Therefore, when the toner T held at the position corresponding to the image exposure L ₂ portion on the toner carrier 11 reaches a predetermined value or more due to the above-mentioned potential difference, the amount of injected charge injected. , Repels the polarity on the toner carrier 11 side by the action of the Coulomb force, and flies to the opposing transfer material P by the action of the above-mentioned electric field to form a developed image.

On the other hand, the toner T in the dark area which is not irradiated with light maintains the negative charge given by the injection charge in the toner amount regulation area A ₁ while maintaining the toner carrier 11.
The toner is not transferred by the electrostatic force acting between the toner and the toner, remains on the toner carrier 11, is collected in the developing container 14 as it is, and is repeatedly subjected to the copying process by the above process.

That is, according to the present invention, as described above, it is possible to form an image on the transfer material P in a non-contact manner. <Second Embodiment> The counter electrode 30 used in the present invention is not limited to the one described in the first embodiment. For example, in order to prevent the toner pattern on the transfer material P from being disturbed by re-injection of charges from the counter electrode 30 side into the toner T once transferred from the toner carrier 11 onto the transfer material P, As shown in FIG. 2, an insulating layer 32 having a resistance higher than that of the toner T may be laminated on the surface of the counter electrode 30. With this configuration,
It is possible to prevent charges from being injected again into the flying toner T, and to form a more stable image on the transfer material P. <Third Embodiment> The toner regulating means of the present invention is not limited to those of the above-described first and second embodiments.
As shown in FIG. 3, a permanent magnet 21 is arranged inside the toner carrier 11, and one of the magnetic poles of the permanent magnet 21 (magnetic pole N
1) and the non-magnetic sleeve 13a of the toner regulating means 13
One of the magnetic poles of the permanent magnet 13b (the magnetic pole S1) is disposed near the position where the toner carrier 11 and the toner regulating means 13 face each other, and the width of the magnetic pole S1 in the axial direction of the toner carrier 11 is further arranged. Is configured to be narrower than the width of the magnetic pole N1, and as the magnetic flux density of the magnetic field formed between the magnetic pole S1 and the magnetic pole N1 changes, the magnetic flux density becomes closer to the toner regulating unit 13 side from the toner carrier 11. The configuration may be higher.

According to the developing device 10 of this embodiment having such a structure, the toner amount is regulated by the following steps.

The toner T having conductivity and magnetism is attracted toward the toner carrier 11 by the magnetic force of the permanent magnet 21, and is rotated on the surface of the toner carrier 11 by the rotation of the toner carrier 11 in the direction of arrow R11. Carried arrow R1
The toner is conveyed in one direction and is further conveyed to a toner amount regulation area A ₁ formed in an area where the toner carrier 11 and the toner regulation means 13 face each other.

In the toner amount regulation area A ₁ , the power source 1
At about the same time that the voltage V ₁ is applied between the toner regulation unit 13 and the toner carrier 11 by the toner 6, the exposure device 17 arranged in the toner carrier 11 causes the toner from the inside of the toner carrier 11. Exposure L ₁ is performed on the entire surface of the carrier region. This exposure process lowers the resistance of the photoconductive layer 11a, and when a voltage is applied, a current flows between the toner regulating means 13 and the toner carrier 11 via the toner T. Further, the photoconductive layer 11 is formed by applying the above-mentioned simultaneous exposure voltage.
A current also flows in a. As a result, charges are injected into the surface of the photoconductive layer 11a, the surface of the photoconductive layer 11a exhibits a certain predetermined charging potential V ₁ depending on the applied voltage, and the toner T in contact with the surface of the photoconductive layer 11a. Photoconductive layer 11
Charges having a polarity opposite to that of the charges injected to the surface a (negative charges in this embodiment) are injected.

Further, in the toner amount regulation area A ₁ , the magnetic flux density becomes higher from the toner carrier 11 to the toner regulation means 13 side, so that the toner T existing in the toner amount regulation area A ₁ is , Toner carrier 1
A magnetic force acts from 1 to the toner regulation unit 13 side.

Therefore, the magnetic attraction force toward the toner regulating means 13 is applied to the toner T to which the electric charge has not been injected.
It works stronger than in the case of the above-mentioned embodiment, and the toner regulating means 1
By rotating the non-magnetic sleeve 13a of No. 3, the developing container 1
4 Inward transport force is given. Further, in the toner T in which the electric charge is injected in the above-described process, the attraction force in the direction of the toner carrier 11 due to the electrostatic attraction with the toner carrier 11 generated by the injected charge and the arrow R11 of the toner carrier 11.
When the toner carrier 11 and the counter electrode 3 are rotated in the direction
A conveying force in the direction of the developing area A ₂ formed between the sheet and 0 is given.

Therefore, as a result of the above-described process, only the injected and charged toner T is coated in a thin layer on the toner carrier 11 more stably than in the first embodiment, and the developing area A is used.
It can be transported in _two directions.

Therefore, only the toner T sufficiently injected and charged in the above step is conveyed to the developing area A ₂ ,
It is possible to prevent the toner T from scattering, which is likely to occur when the injection charge into the toner T is insufficient.

Therefore, according to this embodiment, the transfer material P is subjected to the same copying process as that of the first embodiment, that is, in the non-contact manner.
Forming an image on the surface can be realized in a more stable state. <Embodiment 4> The toner used in the present invention is not limited to the one-component conductive magnetic toner T shown in Embodiments 1 to 3. For example, as shown in FIG.
A two-component developer mainly composed of a conductive magnetic carrier C having a particle diameter of ˜80 μm and a non-magnetic conductive toner T ₀ having a particle diameter of about 10 μm was applied to the developing device 10 of the above-described third embodiment. You may use.

That is, as shown in the figure, the toner carrier 1
1. The permanent magnet 21 is disposed inside the
One of the magnetic poles of the permanent magnet 13b in the non-magnetic sleeve 13a of the toner regulating means 13 (S1) (S1) (S1) (S1).
1) is disposed in the vicinity of the position where the toner carrier 11 and the toner regulating means 13 face each other, and the width of the magnetic pole S1 is set to the magnetic pole N1.
The magnetic flux density of the magnetic field formed between the magnetic pole S1 and the magnetic pole N1 is changed so that the magnetic flux density increases from the toner carrier 11 to the toner regulating unit 13 side. The developer described above may be used in the developing device 10.

In the above structure, the toner amount regulation is performed by the following steps.

The conductive magnetic carrier C is magnetically diffused in the developing container 14 by the rotation of the toner carrier 11 in the direction of arrow R11 and the magnetic force of the permanent magnet 21, and the conductive magnetic carrier C becomes conductive. The toner T ₀ and the conductive magnetic carrier C are carried on the surface of the toner carrier 11 while being agitated and mixed, transported in the direction of arrow R11, and further formed in the area where the toner carrier 11 and the toner regulating means 13 face each other. The toner is transported to the toner amount regulation area A ₁ .

In the toner amount regulation area A ₁ , the power source 1
At about the same time that the voltage V ₁ is applied between the toner regulation unit 13 and the toner carrier 11 by the toner 6, the exposure device 17 arranged in the toner carrier 11 causes the toner from the inside of the toner carrier 11. Exposure L ₁ is performed on the entire surface of the toner carrier area of the carrier 11. The exposure process lowers the resistance of the photoconductive layer 11a, and a current flows between the toner regulating means 13 and the toner carrier 11 via the carrier C and the toner T ₀ by the above voltage application. Also,
A current also flows in the photoconductive layer 11a due to the application of the simultaneous exposure voltage. As a result, charges are injected into the surface of the photoconductive layer 11a, the surface of the photoconductive layer 11a exhibits a certain predetermined charging potential V ₁ depending on the applied voltage, and the photoconductive layer 11a.
Both the carrier C and the toner T _0, which are in contact with the surface, are injected with charges having a polarity opposite to the polarity of the charges injected into the surface of the photoconductive layer 11a (negative charges in this embodiment).

Further, in the toner amount regulation area A ₁ , since the magnetic flux density becomes higher from the toner carrier 11 to the toner regulation means 13 side, the conductive magnetism present in the toner amount regulation area A ₁ is increased. For carrier C,
A magnetic force acts from the toner carrier 11 toward the toner regulating means 13.

Therefore, only the carrier C has a strong magnetic attraction force toward the toner regulating means, and the non-magnetic sleeve 13a of the toner regulating means 13 rotates to convey the carrier C to the inside of the developing container 14. Power is given.
Therefore, by adopting a configuration in which a magnetic force of a certain level or more acts on the carrier C, it becomes possible to return all the carrier C into the developing container 14 as shown by an arrow B in the figure.

Further, by carrying the carrier C as shown by the arrow B, the toner T ₀ is also agitated and mixed with the carrier C, so that a carrying force is applied to the inside of the developing container 14.

[0059] However, in the toner amount regulating region A _1, the toner T _0, since the magnetic force of the toner regulating means 13 direction does not work, the injection charged toner T ₀ is
The attraction force in the direction of the toner carrier 11 due to the electrostatic attraction with the toner carrier 11 generated by the injection charging acts strongly, and the conveyance force is given by the rotation of the toner carrier 11 in the direction of arrow R11, and the toner carrier 11 and It is conveyed in the developing area A ₂ direction between itself and the counter electrode 30. Further, since the electrostatic attraction of the toner carrier 11 does not act on the toner T ₀ to which the charge has not been injected in the above-described process, the toner T ₀ is returned into the developing container 14 by stirring and mixing with the carrier C.

Therefore, by the above-mentioned process, even when the two-component developer as in this embodiment is used, only the injected and charged toner T ₀ is coated in a thin layer on the toner carrier 11, and It is possible to convey the image in the developing area A ₂ direction.

Therefore, according to the present invention, it is possible to form an image on the transfer material P in the same copying step as in the first embodiment, that is, in a non-contact manner.

[0062]

As described above, according to the present invention,
In image formation using a developer containing conductive toner, when the toner is transferred to the transfer material, the toner on the toner carrier is not in contact with the transfer material, so that the contact pressure required for contact transfer It is possible to effectively prevent the transfer image from being disturbed due to the reduction of the suction force due to the charge exchange between the conductive toner and the transfer material surface.

[Brief description of drawings]

FIG. 1 illustrates a schematic configuration of an image forming apparatus according to a first exemplary embodiment.

FIG. 2 illustrates a schematic configuration of an image forming apparatus according to a second exemplary embodiment.

FIG. 3 illustrates a schematic configuration of an image forming apparatus according to a third exemplary embodiment.

FIG. 4 illustrates a schematic configuration of an image forming apparatus according to a fourth exemplary embodiment.

[Explanation of symbols]

Reference Signs List 10 developing device 11 toner carrier 11a photoconductive layer 11b conductive substrate 12 developer transport member 13 toner regulating member 13a sleeve 13b fixed magnet 14 developing container 15 scraper 16 first power supply 17 first exposure device 19 second Exposure device 21 Permanent magnet 30 Counter electrode 31 Second power supply 32 Insulating layer A ₁ Toner amount control area A ₂ Development area C Carrier L ₁ exposure L ₂ Image exposure T, T ₀ toner

Claims (5)

[Claims] 1. An image forming apparatus for forming an image on a transfer material using a developer containing a conductive toner, wherein a light-transmissive conductive substrate and a light-transmissive film formed on the surface of the conductive substrate. Carrier having an electrically conductive photoconductive layer and carrying the toner on the surface on the photoconductive layer side, and a toner on the photoconductive layer which is arranged so as to face the photoconductive layer of the toner carrier. A toner regulating member for regulating the layer thickness of the layer, a first power source for applying a voltage between the toner regulating member and the toner carrying member, and a toner regulating member formed between the toner regulating member and the toner carrying member. A first exposure device that exposes the photoconductive layer from the back surface side of the conductive substrate in the toner amount regulation region, and a downstream side of the toner amount regulation region in the moving direction of the photoconductive layer of the toner carrier. And a counter electrode arranged to face the photoconductive layer. A second power source for applying a voltage between the counter electrode and the toner carrier, and a developing region formed between the counter electrode and the toner carrier, from the back surface side of the conductive substrate. A second exposure device that exposes the photoconductive layer imagewise in response to an electric signal, wherein a portion of the toner on the surface of the toner carrier that corresponds to the image exposure of the second exposure device, An image forming apparatus, wherein the image forming apparatus is made to adhere to the transfer material supplied to the developing area. 2. The surface of the transfer material supplied to the developing region and the toner on the toner carrier are kept in non-contact with each other in the gap between the counter electrode and the toner carrier in the developing region. The image forming apparatus according to claim 1, wherein the image forming apparatus is set to. 3. The counter electrode according to claim 1, further comprising a resistance layer having a resistance higher than that of the toner between the counter electrode and the transfer material in the developing area. Image forming apparatus. 4. An image forming method for forming an image on a transfer material using a developer containing a conductive toner, comprising a toner carrier having a light-transmitting conductive substrate and a light-transmitting photoconductive layer. The toner is carried on the surface of the photoconductive layer side of the body, and the layer thickness of the toner layer on the photoconductive layer is regulated in the toner amount regulation region formed by facing the toner regulation member to the toner carrier. Then, a voltage is applied to the toner amount regulation region to charge the toner on the toner carrier, and the photoconductive layer is exposed from the back surface side of the conductive substrate in the toner amount regulation region, The photoconductive layer is electrically removed from the back surface side of the conductive substrate in a developing area formed by facing a counter electrode to the toner carrier on the downstream side of the toner amount regulation area in the moving direction of the photoconductive layer. Image exposure according to a signal, An image forming method, comprising applying a voltage to a developing area to transfer the toner on the toner carrier to a transfer material inserted in the developing area so that the toner adheres. 5. The image forming method according to claim 4, wherein the transfer material is inserted into the developing area in a state of not contacting the toner on the toner carrier.