JP3484935B2 - Charging device and image forming apparatus using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device used in electrophotographic devices, electrostatic recording devices and the like, and an image forming apparatus using the charging device as a transfer device.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic device or an electrostatic recording device, a corona discharge device has been generally used for charging a photosensitive member or an image bearing member. This corona discharge device has a corotron system and a scorotron system. FIG. 19 is a schematic configuration diagram showing a corotron type corona discharge device. The main part of this corona discharge device is composed of a discharge wire 102 stretched to face an object to be charged and a conductive shield 103 arranged so as to cover the discharge wire 102. The discharge wire 102 has a wire diameter of about several tens of μm, and a high voltage is applied between the discharge wire 102 and the object to be charged. Then, by the corona discharge, ions are generated around the discharge wire 102, and the movement of the ions causes the object to be charged to be charged. Such a corona discharge device is capable of imparting a sufficient amount of discharge charge to an insulating charged object with a simple structure.

Further, as another device for charging the photoreceptor,
JP-A-50-843, JP-A-50-13661, JP-A-64-73367, JP-A-58-1
50975, Japanese Patent Laid-Open No. 4-51266, 4-
Some are disclosed in Japanese Patent No. 249270.
The devices disclosed in JP-A-50-843, JP-A-50-13661, and JP-A-64-73367 make a roll, which is a resistor, contact a photoconductor to expose the roll and the photoconductor. A voltage is applied between the body and the body, and a continuous discharge is generated in the minute gap to charge the body. Further, JP-A-58-150975 and JP-A-4-51
In the devices disclosed in Japanese Patent No. 266, 4-249270, etc., a high-resistance and conductive film is brought into contact with a photoconductor, and a voltage is applied between the photoconductor and the photoconductor to discharge in a minute gap. It is what causes it.

On the other hand, as a device for charging the toner, Japanese Patent Application Laid-Open No. 60-83972 and Japanese Patent Application Laid-Open No. 54-1
7030, JP 62-291678, JP 6
There is one disclosed in Japanese Patent Publication No. 4-62675 and the like. In the device disclosed in Japanese Patent Laid-Open No. 60-83972, a plurality of electrodes are laminated in parallel on an insulating substrate, and the electrodes are opposed to a developing roll on which a thin layer of toner is formed. By applying a discharge voltage in between, the toner on the developing roll is charged.

The devices disclosed in Japanese Patent Laid-Open Nos. 54-17030, 62-291678, and 64-62675 are as shown in FIGS. 20 (a) and 20 (b). A roller-shaped electrode 112 or a blade-shaped electrode 113 to which a voltage is applied is brought into contact with the toner layer on the developing roller 111, and the toner is charged by the discharge generated in the minute gap. Generally, in a developing device using a one-component developer, the toner is charged by friction with a toner layer regulating member that is in pressure contact with a developing roll, but such a method imparts a sufficient charge to all toner particles. It is difficult to produce toner of opposite polarity. In order to avoid such a state, there has been proposed a technique of charging the toner on the developing roll by using the above charging device. The toner of the opposite polarity is a toner that has been charged to the opposite polarity to the polarity that the toner is to be charged,
When toner is charged with a negative polarity and development is performed, the toner is charged with a positive polarity.

On the other hand, in the image forming apparatus of the electrophotographic system or the electrostatic recording system, a latent image due to a difference in charging potential is radiated by irradiating an image light, and a latent image is formed on the peripheral surface of the image carrier (conductive substrate). Image on the image receptor by transferring the developed toner image to an image receptor such as paper while forming a latent image on the latent image with a developer such as toner. Forming. Then, as a method of transferring the developed toner image to the image receiving body, as shown in FIGS. 23 (a) and 23 (b), a corotron 123, 133 is used to form an image receiving body 124 or a support 135 of the image receiving body. A method of applying an electric charge is generally used. For example, Japanese Patent Application Laid-Open No. 61-11772 discloses a corona discharge device as a charging device for such an image receptor 124. In FIG. 23, reference numerals 121 and 131 denote image carriers,
Reference numerals 122 and 132 are discharge electrodes of the corotron, and reference numeral 12
Reference numeral 6136 indicates a power source.

On the other hand, as another typical charging method, a bias roll method (for example, Japanese Patent Laid-Open No. 6-1918) is used.
9 disclosure). In this bias roll method, a roll of a resistor is pressed against an image carrier through an image receptor or a support of the image receptor. Then, a high voltage is applied to the central part of the roll to form a transfer electric field from the bias roll side to the image receptor to charge the image receptor. In addition, a method is also known in which a high-resistance conductive film or conductive brush is arranged on the back surface of the support of the image receptor, not the conductive material of the roll, and a voltage is applied to such a conductive material to supply an electric charge. Has been. This method is disclosed in, for example, Japanese Patent Laid-Open No. 62-285833.

[0008]

However, the above-described conventional charging device has the following problems.
In a corotron type device that generates corona discharge, it is necessary to prevent the discharge charge from going to other than the electrode side on which the insulator to be charged is placed, and a conductive shield is provided to stabilize the discharge. It is necessary to install it. If this shield is brought too close to the discharge electrode (discharge wire) and enters the ionization region, a spark discharge will occur between the two.Therefore, keep a certain distance or more between the discharge electrode and the conductive shield. There must be. Therefore, the size of the shield cannot be made too small,
The corotron was not very suitable for downsizing the charging device.

Further, in any charging device for applying a voltage to a roll-shaped electrode or a film-shaped electrode made of a resistor, an electrode on which an object to be charged is placed is brought close to the resistor, and an electric field directed to the electrode is used to discharge the charge. It is to give. Therefore, in order to form a discharge electric field, the gap between the two must be extremely narrowed, and in many cases, since they are in contact with each other, foreign matter adheres to the discharge electrode side and disturbs the charging characteristics. That is, when it is used for charging a photoconductor or the like, there is a problem that the charging characteristics may change or become non-uniform due to adhesion of toner-containing substances or paper powder remaining on the photoconductor or abrasion of the surface. .

On the other hand, a charging device for applying a voltage to a roll-shaped electrode or a blade-shaped electrode made of a resistor has the following problems when used as a device for charging toner. As shown in FIGS. 21 (a) and 21 (b), a resistor electrode to which a voltage is applied is brought into contact with the toner layer to cause a discharge phenomenon between the electrode and the developing roll or between the electrode and the member carrying the toner. Therefore, the toner is present in the discharge phenomenon that occurs between the two, and the charged toner does not have the desired polarity, and so-called reverse polarity toner is generated.

The following phenomenon is conceivable as the mechanism of generation of this reverse polarity toner. Electron avalanche phenomenon occurs due to ionization accompanying discharge, and positive ions and electrons or negative ions having opposite polarities are generated. Moreover, as shown in FIG. 21, since the toner is present in the discharge area, both positive ions and electrons or negative ions give electric charges to the toner, so that the toner of the opposite polarity is generated.

For example, based on the document "Discharge Phenomenon" (Tokyo Denki University Press, Koji Honda, p. 64), parallel 2
When the relative densities of electrons and positive ions generated between the two electrodes are calculated, as shown in FIG. 22, the positive ions are also present in the immediate vicinity of the anode (developer carrier) and the size of the toner is large. At (7-10 μm), it is shown that there are thousands of times as many electrons. In addition, each toner particle is produced one by one by the method described in the document “Recent Development and Practical Use of Electrophotographic Development System and Toner Material” [Nippon Scientific Information Co., Ltd. Publishing Department, Manabu Takeuchi, page 303]. According to the result of measuring the polarity and the charge amount as distribution, the reverse polarity toner is 20 wt%. Further, the charging device described in JP-A-60-83972 has the same problem.

On the other hand, when the corotron charging device is used in the transfer device of the image forming apparatus, there are the following problems. As shown in FIG. 23A, when only the image receptor 124 is interposed between the image carrier 121 and the corotron, and when the image receptor support is not present, the image is formed by the charge attached to the image receptor 124. Since it is attracted to the carrier 121 and the transfer nip width (the width where the image receiver is in contact with the image carrier) is widened, it is not a serious problem. However, the positioning of the image receiver is particularly important as in color multiple transfer, and the support 1
23, the toner image is transferred onto the image receiving member 134 on FIG.
In the case shown in (b), the transfer nip width is narrower than the width of the corotron 133 in order to constrain the image receiving member 134 to the support member 135 by the electrostatic force or the claw-shaped member 137.
Also at the upstream side of the transfer nip (hereinafter, referred to as the transfer nip) and the downstream side of the transfer nip (hereinafter, the transfer nip) with respect to the moving direction of the image receiving member 134 (that is, the moving direction of the support 135). The discharge charge from the corotron is applied, and toner scattering called blur occurs around the image portion as shown in FIG.

The reason for this will be described in the case where the image receiving member 134 is on the support 135 as shown in FIG. 23B. The electric charge supplied from the corotron has already adhered to the back surface of the support 135 before the transfer nip. The toner on the image carrier 131 flies in the space between the image carrier and the image receptor by the action of the electric field generated by the electric charge and the conductive substrate of the image carrier 131, and is transferred to the image receptor 134. It
In the transfer nip, the toner is transferred to the image receiving member 134 while being pressed against the image bearing member and the image receiving member, and blurring is less likely to occur because the toner is bound to some extent by the electric field created by the electrostatic latent image, but the toner When the image is transferred to the image receiving member 134 by flying through the gap between the image bearing member and the image receiving member, the pressing force against the toner does not work and the toner is also moved away from the electric field created by the electrostatic latent image, so that the toner remains static. It tends to spread out from the size of the image formed by the latent image and adhere to the image receptor.
This phenomenon is the same when a cylindrical support is used instead of the belt support 135 in FIG. 23 (b).

To solve such a problem, there is a method of preventing the discharge charge from adhering to the image receptor 134 before the transfer nip by using an insulating or conductive shield 138 as shown in FIG. 25. It is disclosed in Japanese Patent Application Laid-Open No. 8-286524. When the spread of the discharge charge is limited by such a method, it is desirable that the end of the shield 138 is located on the line connecting the discharge electrode 132 and the upstream end of the transfer nip. The method requires a considerable sacrifice in the discharge efficiency of the corotron. Therefore, the voltage applied to the discharge electrode 132 and the total current increase, which causes various problems such as an increase in cost due to insulation measures, a shorter life of the charging member such as the discharge electrode 132, and an increase in ozone generation amount.

Further, in the charging device of the corotron system, discharge charges can be supplied to the image receptor or its support even on the downstream side of the transfer nip. The toner accumulated on the upper portion is attracted to the peripheral image receiving member which is not originally the image portion by the discharge charge on the downstream side of the transfer nip, and the tendency that the toner around the thin line is scattered is increased.

On the other hand, in a system in which a roll of a resistor to which a voltage is applied is brought into contact with the image receptor or the back surface of the support of the image receptor, that is, in the bias roll system, the adhesion between the image receptor and the image carrier at the transfer nip is improved. In order to secure the pressure, the resistor roll needs to be pressed against the image receptor, and the pressure tends to cause white spots as shown in FIG. 24 (b) in the transfer of thin lines and the like. Further, in a method in which a voltage is applied to a conductive film or brush to supply charges from the back surface of the support of the image receptor, the charge supply performance deteriorates due to abrasion and the like, and sufficient reliability cannot be obtained for a long time. There was a flaw.

The present invention has been made in view of the above problems, and an object thereof is to prevent foreign matters from adhering by making a non-contact with an object to be charged and to reduce the size of the charging. It is to provide a device. In addition to the above, when used as a toner charging device, the generation of reverse polarity toner is suppressed by applying a unipolar charge, and a small size that enables stable image formation for a long time in the image forming apparatus. It is to provide a charging device of. Further, as a transfer device to the image receiving body, a charging device which efficiently supplies electric charges to a narrow range is used, even though the charging device is supported in a non-contact manner with respect to the image receiving body or the support of the image receiving body. An object of the present invention is to provide an image forming apparatus capable of preventing scattering of a developer and white spots in an image area.

[0019]

In order to solve the above-mentioned problems, the invention according to claim 1 is arranged so as to be close to and spaced from an object to be charged on a conductive substrate, and the object to be charged is charged. A charging device for applying a charge, comprising: a plate-shaped first electrode made of a resistor and a plate-shaped member made of a resistor or a conductor.
And an interposing portion made of the first electrode and an insulating material
A second electrode adhered with a material sandwiched between them and formed into a plate shape.
The end faces of the first electrode and the second electrode are
The interposing member is arranged so as to face the base body,
Ends of the first electrode and the second electrode facing the charged object
Receded from the end surface in the same plane as the surface or from the end surface
A voltage is applied between the first electrode and the second electrode such that a continuous discharge is generated , and the end face is provided at a position, and the first electrode or the second electrode is applied. And the substrate, a potential of the first electrode and the second electrode so that an electric field is formed in which ions or electrons having a polarity charge imparted to the object to be charged move to the substrate side. Is provided for the charging device.

In the above charging device, the first electrode is made of a resistor, that is, a conductor having a high resistance. Also,
The second electrode may be made of a conductor or a resistor. This is to prevent spark discharge from occurring between the first electrode and the second electrode by using one of them as a resistor in order to generate a continuous discharge. Therefore, the volume resistivity of the resistor is set within a range in which spark discharge can be prevented and continuous discharge can be generated.

In the above charging device, the electric potentials of the first electrode and the second electrode may have the same polarity or different polarities. These potentials are determined by the relationship with the potential of the substrate while maintaining a potential difference that causes a continuous discharge therebetween. That is, the electric potential is set between the first electrode or the second electrode and the substrate to form an electric field so that the ions or electrons of the polarity to be charged are induced to the substrate side. It is as follows.

If the polarity for charging the object to be charged is negative, an electric field is formed between the low potential (negative side) electrode of the first electrode and the second electrode and the substrate. And
The potential is set so that the electrode has a low potential (negative side) with respect to the substrate. At this time, either the other electrode (the electrode on the higher potential side) or the base body may have a higher potential, but a range that does not generate an electric field that cancels the electric field between the base body and the other electrode To do. In other words, when the other electrode (the electrode on the high potential side) becomes significantly higher in potential than the substrate and an electric field is formed, ions of opposite polarity will move, and such an inconvenience will not occur. Set to.

In such a charging device, when a potential difference equal to or higher than the discharge start voltage is applied between the first electrode and the second electrode arranged in proximity to the first electrode to cause a discharge phenomenon between the two, Ionization due to discharge between the two causes electron avalanche, and positive ions and electrons or negative ions are generated between them, and these move between the first electrode and the second electrode, respectively. Then, when the voltage difference between the first electrode and the second electrode facing the first electrode is further increased, the substrate facing the first electrode or the second electrode close to and facing the first electrode at a certain voltage difference. Current flows through. As a result, the object to be charged on the substrate can be charged.

Further, in this charging device, the first electrode and the second electrode
Are placed in close proximity to the electrodes and each does not require a large volume. Since the gap with the base body carrying the object to be charged is also small, the entire charging device can be downsized. Further, since the object to be charged can be charged in a non-contact manner, it is possible to prevent the charging characteristic from changing due to adhesion of foreign matter.

The phenomenon in which a current flows from the first electrode or the second electrode to the substrate in the above charging device can be considered as follows. When the electric discharge between the first electrode and the second electrode becomes strong to some extent, the amount of positive ions and electrons or negative ions that move along the electric field between both electrodes increases, and the repulsive force due to collision or electric charge increases. As a result, the electric charge distribution will be out of the discharge electric field between both electrodes. This changes the electric field distribution near the two electrodes,
It is presumed that an electric field path is generated from the vicinity of both electrodes to the conductive substrate, and ions or electrons ionized by a strong electric field near the two electrodes flow along the electric field path.

As described above, the ionization region is limited to the vicinity of the first electrode and the second electrode which are adjacent to each other, and the ions or electrons ionized by the non-uniform electric field are generated in the first electrode or the second electrode. Since it is induced toward the object to be charged according to the electric field path between the substrate and the opposite substrate, there are almost no ions or electrons of the opposite polarity to the one to be charged around the object to be charged, Charging is performed with a unipolar charge.

Further, in the charging device as described above, the gap between the two electrodes can be easily set to a predetermined value by adjusting the thickness of the insertion member. Then, by aligning the end surface of the insertion member with the end surface of the electrode member or at a position retracted from the end surface, discharge can be generated between the end surfaces of the two electrodes or the facing surface in the vicinity thereof.

According to a second aspect of the present invention, there is provided the charging device according to the first aspect.
The charging device according to claim 1, wherein the first electrode and the first electrode are
The peripheral surface of the end surface with the second electrode is supported so as to be endlessly movable.
It is arranged in close proximity to the belt or cylinder, and
In the width direction of the peripheral surface of the cylindrical body, is opposed to the peripheral surface at equal intervals
Be supported to do so.

In such a charging device, as long as the belt or the cylindrical body has the electrically conductive base member on the conductive base member, it can be charged substantially uniformly in the width direction. For example, if the belt or the cylindrical body is an image carrier used in an electrophotographic apparatus or an electrostatic recording apparatus, this peripheral surface can be uniformly charged to a predetermined potential. If the belt or the cylindrical body is a developing roll or a developer carrying body arranged to face the image carrying body, a thin layer of toner formed on this peripheral surface is uniformly charged in the width direction. It becomes possible.

The charging device according to claim 3 is the charging device according to claim 2.
The charging device according to claim 1, wherein the back surface of the first electrode
, A power supply member made of a conductive material is adhered,
The first electrode is evenly distributed in the width direction of the circumferential surface of the belt or the cylindrical body.
Shall be thick.

In such a charging device, a conductive power feeding member is adhered to the electrode made of a resistor, and a voltage is applied by this. Then, when a discharge is generated between the first electrode and the second electrode, a potential difference is generated even in one electrode between the surface facing the other electrode and the portion where the power feeding member is in contact. . However, since the power supply member is adhered to almost the entire back surface of the electrode and the thickness of this electrode is uniform,
The potential difference between the portion where the power feeding member is adhered and the surface where the electric discharge is generated is substantially constant in the width direction of the belt or the cylindrical body. Therefore, a substantially uniform discharge occurs in the width direction, and uniform charging is possible.

On the other hand, in order to solve the above-mentioned problem that occurs when a corotron type or contact type charging device is used in a transfer device of an image forming apparatus, the invention according to claim 4 is
A conductive base having an endless peripheral surface that is orbitally driven and a dielectric layer or a photosensitive layer formed on the peripheral surface of the base are provided, and a latent image due to a difference in electrostatic potential is formed on the peripheral surface. An image bearing member formed on the image bearing member, a developing device for visualizing the latent image on the latent image on the image bearing member by applying a developer to the latent image, and the image bearing member arranged to face each other. an image forming apparatus having a transfer device for transferring the developer image to a receiver member passing between the transfer device consists of a resistor
A plate composed of a plate- shaped first electrode and a resistor or conductor
A member having a shape of a strip and made of an insulating material and the first electrode.
A second electrode adhered with an interposing member interposed therebetween ,
The end faces of the plate-shaped first and second electrodes are
Both are arranged so as to face the back surface of the image receptor,
The interposing member is a strip of the first electrode and the second electrode.
Charged object in the same plane as the end surface facing the electric object or from the end surface
It has an end face in a retracted position with respect to
A continuous discharge is provided between the first electrode and the second electrode.
A voltage is applied to generate a charge, and the first electrode or
The image receptor is attached between the second electrode and the substrate.
Ions or electrons having a polar charge imparting to the substrate side
To the first electrode so that an electric field to be moved to
Image forming apparatus in which each potential of the second electrode is set
I will provide a.

In such an image forming apparatus, when a potential is applied between the first electrode and the second electrode facing the first electrode to form an electric field higher than the start of discharge between both electrodes and a discharge phenomenon occurs, the two electrodes are discharged. At this point, ionization due to discharge occurs, electron avalanche occurs, and a large amount of positive ions and electrons or negative ions are generated between both electrodes. Then, these move to the cathode and the anode, respectively.

When the potential difference between the first electrode and the second electrode facing the first electrode is further increased, a conductive substrate which faces the first electrode or the second electrode close to and faces the first electrode at a certain potential difference. An electric current begins to flow between and. Thereby, the image receptor or the image receptor support disposed between the first and second electrodes and the substrate can be charged from the back surface with a unipolar charge, and the developer image can be transferred from the image carrier to the image receptor. You can

In the image forming apparatus having the transfer device, the first
The gap between the electrode and the opposite second electrode is placed very close to each other to generate the discharge, and each does not require a large volume. Moreover, by approaching the image receptor or the back surface of the support of the image receptor, the area where the charges adhere to the image receptor or the back surface of the support surface of the image receptor can be narrower than the transfer nip width. As a result, it is possible to solve the above-mentioned problem caused by the charge being applied before and after the transfer nip. Further, since the first and second electrodes serve as the other shield, the discharge can be stabilized. In addition, since electric charges can be applied to the image receptor or the back surface of the support of the image receptor in a non-contact manner, problems such as white spots in thin lines, abrasion, and adhesion of foreign matter do not occur.

According to a fifth aspect of the present invention, in the image forming apparatus having the above structure, the first electrode and the second electrode are provided.
Of the electrode is disposed so as to face the image carrier or the image receptor support whose peripheral surface is endlessly movably supported, and the periphery of the electrode in the width direction of the endless peripheral surface of the image carrier or the image receptor support. It is supported so as to face the surface at equal intervals. This makes the first
The amount of discharge current between the second electrode and the second electrode can be made uniform in the plane of the image receptor support and the like, and the image receptor can be charged almost uniformly in the width direction, so that a uniform image can be obtained. be able to.

[0037] In the image forming apparatus according to claim 6, wherein
In addition to the configuration of Item 4 , a power feeding member made of a conductive material is adhered to almost the entire back surface of the first electrode and the second electrode made of a resistor, and the first electrode and the second electrode The second electrode is configured to have the same thickness in the width direction of the endless peripheral surfaces of the image carrier and the image receptor support.

In such an image forming apparatus, since the voltage is applied to the electrode made of the resistor through the conductive power feeding member, the supply of the discharge charge is stabilized. Then, when a discharge is generated between the first electrode and the second electrode, even within one electrode (inside the resistor), the surface facing the other electrode and the discharge are generated Although a potential difference is generated between the contacting surface and the contact surface, the power supply member is adhered almost all over the back surface of the electrode, and since the thickness of this electrode is even in the width direction, the power supply member is adhered. The potential difference between the side surface portion where the discharge occurs and the side surface where the discharge occurs is substantially constant in the width direction of the endless peripheral surface, and a substantially uniform discharge occurs in the width direction. Therefore, the image receptor can be charged substantially uniformly in the width direction, and a uniform image can be obtained.

The image forming apparatus according to claim 7 is a circuit
A conductive base having an endless peripheral surface to be driven;
A dielectric layer or a photoconductor layer formed on the peripheral surface of the substrate
Image formed on the peripheral surface by a latent image due to the difference in electrostatic potential
Attach the developer to the carrier and the latent image on the image carrier.
A developing device for visualizing the latent image is provided to face the image carrier.
Is placed on the image receiving body that passes between the image carrier and the image carrier.
An image forming apparatus having a transfer device for transferring an image agent image.
The transfer device consists of a resistor and
First electrodes that are divided into a number and are arranged at equal intervals
And a resistor or conductor and divided into multiple parts on the substrate.
Each of the divided electrodes is divided into the first electrodes.
A second electrode arranged equidistant from
That of the divided portion of the first electrode and the second electrode
Each of them should penetrate the substrate from the back side to the front side.
It is a cylindrical body provided, from the first electrode and the resistor
In the cylindrical body of the second electrode,
An electrically conductive power supply member is inserted, and the first electrode and
A continuous discharge may be generated between the second electrode and the second electrode.
A voltage is applied to the first electrode or the second electrode
Between the base and the substrate, an electric field having a polarity applied to the image receptor is provided.
Electric field in which a charged ion or electron moves to the substrate side
So that the electrodes of the first and second electrodes are formed.
An image forming apparatus in which the position is set is provided.

The first electrode and the second electrode are respectively
It is composed of a plurality of divided members, but the first
All of the members that make up the electrodes are set to the same potential,
All the members that make up the electrodes are also set to the same potential.
Of. A discharge occurs between such electrodes and these
Some of the ions or electrons that move between the poles flow to the charged object.
Is charged. And a part forming the first electrode
The material and the arrangement of the members that make up the second electrode are appropriately selected.
The charging range and charging strength
Can be set to.

The image forming apparatus according to claim 8 is
Conductive substrate having an endless peripheral surface that is orbitally driven
And a dielectric layer or photoconductor formed on the peripheral surface of the base
And a latent image is formed on the peripheral surface due to the difference in electrostatic potential.
Image carrier and the latent image on the image carrier with developer.
And a developing device for visualizing the latent image by attaching the image bearing member to the image bearing member.
Is placed so as to face the image carrier and passes through between the image carrier and the receiver.
Image formation having a transfer device for transferring a developer image to an image body
A transfer device comprising a resistor,
A first electrode arranged to face the base;
It is composed of a resistor or a conductor and faces the substrate.
Also, they are arranged side by side so as to be in close contact with the first electrode without contacting them.
A second electrode formed by:
Direct current between the electrodes of the
Pressure is applied to the front of the first electrode or the second electrode.
Between the base and the substrate, a polar charge imparted to the image receptor is applied.
The electric field in which the ions or electrons possessed move to the substrate side
So that the potentials of the first and second electrodes are
The present invention provides a set image forming apparatus .

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the invention relating to the charging device of the present application will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a schematic configuration diagram showing a charging device according to an embodiment of the invention described in claim 1, claim 2 or claim 3, and a developing device in which the charging device is used. 2 is a schematic configuration diagram of FIG. The developing device 2 using this charging device selectively transfers toner to the image carrier 1 in an electrophotographic device or an electrostatic recording device to visualize an electrostatic latent image on the image carrier 1. The developing roller 3 rotates while carrying a thin layer of toner on the peripheral surface, and transfers the toner to the image bearing member in the developing area facing the image bearing member. A bias voltage is applied to the developing roll 3 from a power source 4 to form an electric field between the developing roll 3 and the image carrier to transfer the charged toner to the image carrier. Therefore, the toner needs to have an appropriate charge, and the charging device 5 of the present embodiment is used as a device for charging so that each particle of the toner holds an appropriate charge.

The charging device 5 is arranged so as to face the developing roll 3 as shown in FIG.
As shown in (b), the first electrode 11 made of a resistor is used.
And a second electrode 12 made of a conductive material, which is attached via a spacer 13 made of an insulating material, and a power feeding member 14 adhered to the back surface of the first electrode. ing.

The first electrode 11 is composed of a semiconductive plate-like member in which powder of a conductive material is dispersed and mixed in silicon rubber, and has a volume resistivity of about 10 ⁶ Ω · cm.
Has become. Further, the thickness of this electrode is 1.5 mm, and the rear surface of the power supply member 14 has a thickness of 0.2 mm S.
The US plate is adhered. As a result, the total thickness is about 2
It is a charging device of about mm. The minimum size of these corotrons is about 10 mm, so about 1
/ 5. In addition, reference numeral 15 shown in the drawing denotes a power feeding member 14.
It is an insulating member attached to prevent spark discharge from occurring between the developing roller 3 and the developing roller 3. On the other hand, the second electrode 12 is made of a SUS plate having a thickness of 0.2 mm, and is sandwiched by a spacer 13 having a thickness of 70 μm and bonded to the first electrode 11. The end faces of the first electrode 11 and the second electrode 12 are arranged so as to face the peripheral surface of the developing roll 3 at a distance of 500 μm, and the spacer 13 interposed between them is It is sandwiched so that the end face is located at a position retracted 2 mm from the end face of the first electrode 11 or the second electrode 12. The charging device 5 is opposed to the developing roller 3 in the axial direction, that is, in the widthwise direction of the developing roller circumferential surface, and has a uniform cross section.

The DC component of the bias voltage applied to the developing roll 3 is -400V, and the DC power supplies 6, 7 are applied to the first electrode 11 and the second electrode 12, respectively.
From the DC power source 6, the potential of the first electrode 11 is set to -2400V, and the potential of the second electrode 12 is set to -400V by the DC power source 7.

In such a charging device 5, as shown in FIG. 2, a continuous discharge is generated between the first electrode 11 and the second electrode 12, and an electron avalanche is generated between both electrodes. , Ions and electrons are generated by ionization. These ions and electrons move along the electric field between the electrodes, positive ions move from the second electrode 12 side to the first electrode 11 side, and negative ions and electrons move in the second electrode 12 side. Move to the side.
At this time, the negative ions and a part of the electrons flow toward the developing roll 3 side by the electric field between the first electrode 11 and the developing roll 3, and the toner carried as a thin layer on the developing roll 3 is discharged. The particles 8 are charged. As described above, since the charges moving from the charging device 5 to the developing roll 3 side are limited to negative ions or electrons, almost all the toner particles 8 on the developing roll are negatively charged, and the toner particles charged to the opposite polarity are , There is almost no toner on the developing roll 3. The toner thus appropriately charged is transferred to the image carrier 1 in the developing area. At this time, since the toner has a sufficient charge, an appropriate amount of toner is transferred to the latent image on the image carrier 1 and a good image is formed. Further, the toner having the opposite polarity does not transfer to the background portion to cause fogging.

Next, an experiment conducted to confirm the operation of the above charging device will be described. (First Experiment) In this experiment, as shown in FIG. 3, the charging device 21 having the same configuration as the charging device 5 of the above embodiment is made to face the aluminum plate 22, and the first electrode 23 and the second electrode The electric potential is applied to the electrode 24 and. The aluminum plate 22 is grounded and an ammeter 25 is provided for measuring the amount of current flowing to the ground. The material and thickness of each member of the charging device 21 used in this experiment are the same as those of the charging device shown in FIG. 1, but the depth of the device (direction perpendicular to the paper surface in FIG. 3) is 17 mm.

First, as a preliminary experiment, the first electrode 2
A potential difference was applied between the third electrode 24 and the third electrode 24, the difference between the first electrode voltage Va and the second electrode voltage Vb was changed, and the current value flowing between them was measured. The result is shown in FIG. As shown in this figure, the difference (Va-Vb) between the potential Va of the first electrode 23 and the potential Vb of the second electrode 24 is -7.
The current amount sharply increases from around the point where it exceeds 00V. In the range where the current amount increased, light emission between both electrodes was observed in the dark, and it was confirmed that discharge occurred. It should be noted that some current is observed even when the potential difference (Va-Vb) between both is −700 V or less, but this is considered to be because a weak current flows through a spacer or the like.

Next, the potential Va of the first electrode 23 is set to -20.
When the potential Vb of the second electrode 24 is changed by setting it to 00V, the distance d = from the facing portion of the first electrode and the second electrode.
The amount of current flowing through the aluminum plate 22 placed at a distance of 500 μm was measured with an ammeter 25. The result is shown in Fig. 5.
Shown in. As shown in this figure, when the potential of the second electrode 24 is gradually increased from -2000V, -700V is obtained.
Voltage (both potential difference Va-Vb is about 1300V), almost no current flows to the aluminum plate 22, and -300 to -200V (potential difference 1700 to 180).
When it reaches 0V, it has risen significantly. Therefore, it is understood that a current is generated to the aluminum plate 22 when the strong discharge is generated between the first electrode 23 and the second electrode 24.

The current to the aluminum plate 22 is not due to the direct discharge between the first electrode 23 or the second electrode 24 and the aluminum plate 22, and the potential of the second electrode 24 is It is clear from the fact that when -2000 V (Va-Vb = 0), that is, when the largest electric field is generated between the two electrodes and the aluminum plate, almost no current is generated from the electrodes to the aluminum plate. Is.

In the above experiment, even if the first electrode 23 and the second electrode 24 are exchanged, that is, the second electrode 2 is replaced.
The same result can be obtained by setting the potential of No. 4 to -2000V and changing the potential of the first electrode 23. Further, similar results were obtained by using resistors for both the first electrode 23 and the second electrode 24. In addition, in performing this measurement,
When 2.1 kV or more was applied to the power supply member 26 of the first electrode 23, spark discharge occurred to the aluminum plate.
It was covered with an insulator. After that, even when a larger voltage is applied, the distance d between the end face of the electrode and the aluminum plate
No spark discharge was generated from the power supply electrode 26 even if the value was made smaller.

(Second Experiment) In this experiment, the apparatus 21 shown in FIG. 3 was used, and the first electrode 23, the second electrode 24 and the aluminum plate 22 were used.
The amount of current flowing from the electrode to the aluminum plate 22 was investigated when the distance d between and was changed. The distance d between the electrode and the aluminum plate is 280 μm, 7
The electric potential Va of the first electrode 23 was set to -1500V, and the electric potential Vb of the second electrode 24 was gradually increased from -1500V to observe the amount of current. The result is shown in FIG. The distance between the first electrode 23 and the second electrode 24,
That is, the thickness of the spacer 27 is set to 25 μm.

As shown in FIG. 6, when the distance d between the electrodes 23 and 24 and the aluminum plate 22 is any, the movement of charges to the aluminum plate 22 is recognized, but when the distance d is small, a large current is generated. It turns out to be the amount. Further, the potential Vb of the second electrode 24 increases,
The amount of current increases as the potential difference from the first electrode 23 increases, but the amount of current decreases as the potential of the second electrode 24 further increases. This is because when the potential Vb of the second electrode 24 rises above the potential (0V) of the aluminum plate 22, an electric field in the opposite direction is formed between the second electrode 24 and the aluminum plate 22, and the charges are transferred to the aluminum plate side. It is thought to be difficult to do. Therefore, the potential of the second electrode 24 and the aluminum plate 2
The relationship with the electric potential of 2 may be large, but it must be set so that an electric field that prevents transfer of charges of a desired polarity is not generated between them.

(Third experiment)
In this experiment, using the apparatus shown in FIG. 7, the gap g between the first electrode 33 and the second electrode 34 was changed, and the amount of current flowing from the first or second electrode to the aluminum plate 32 was investigated. It is a thing. In the device shown in FIG. 7, a spacer 35, which is interposed between a first electrode and a second electrode as a charging device 31, is aligned with the end faces of both electrodes facing the aluminum plate 32. The other configuration is the same as that of the device 21 shown in FIG. Further, the distance g between the first electrode 33 and the second electrode 34 is 25 μm, 70 μm, 140 μm.
It is assumed that m is set, and the value of g is changed by changing the thickness of the spacer 35.

The results of the above experiment are shown in FIG. 8. From this figure, the end faces of the first electrode 33, the second electrode 34, and the spacer 35 are arranged in the same plane, and the first electrode is formed. It can be seen that even if there is no portion where 33 and the second electrode 34 directly face each other, electric discharge occurs between the two and the electric charge moves to the aluminum plate 32. Further, as the distance g between the first electrode 33 and the second electrode 34 is smaller, the movement of charges occurs even if the potential difference between the two is smaller, and the amount of current also becomes larger as the distance g between both is smaller. Therefore, the first electrode 3
If the gap g between the third electrode 34 and the third electrode 34 is set to be small, the potential difference applied between the two may be small. On the other hand, when the distance g between the two becomes large, the potential difference must be increased, and the potential must also be set large. Therefore, spark discharge is likely to occur between the surrounding electrically conductive material.

According to the experiment, the second electrode voltage Vb in FIG.
By expanding the potential difference between electrodes by 100V + from the voltage at the final plot point of the curve corresponding to each interval g plotted by changing
Spark discharge occurred from the first electrode 33 to the aluminum plate 32 side. Therefore, like the toner on the metal sleeve, when the charged object is placed on the conductive substrate and there is a gap between the charged object and the charged object, the potential difference that causes the spark discharge is different from each condition. Will determine the upper limit of the applied voltage difference.

The maximum value of the gap g between the first electrode and the second electrode depends on the potential difference (Va-Vb) applied between the electrodes and the distance d between the aluminum plate (object to be charged) and each electrode. . When the distance g = 140 μm, the potential difference between the electrodes is 2
At 500V, a small amount of current will finally flow,
If the potential difference between the electrodes is increased, spark discharge is likely to occur between the conductive material in the surroundings, and even if the first and second electrode pairs are brought close to the charged object, the conductive material is not discharged to the charged object side. If it is exposed, spark discharge is more likely to occur. Also, the first
If the second electrode pair is moved away from the object to be charged, it becomes more difficult to be charged. Therefore, in the charging device according to the present invention, it is judged that the charging device becomes ineffective when the gap g exceeds about 140 μm. It is considered that this is because it becomes difficult for discharge to occur between the first electrode and the second electrode.
Further, the aluminum plate potential V is not necessarily Va in order to pass a current of a desired polarity to the aluminum plate 32 from FIG.
It is understood that it is not necessary that>Vb> V (or Va <Vb <V), and Va>V> Vb may be used in view of the desired polarity.

FIG. 9 shows the results of measuring the current flowing into the aluminum plate 32 while changing the distance d from the object to be charged using the apparatus of FIG. As can be seen from this figure, the inflow current is clearly recognized even at d = 1000 μm. Further, when the second electrode potential Vb increases to the opposite polarity side of the first electrode potential Va and its absolute value approaches | Va |, the current flowing into the aluminum plate 32 tends to decrease. This is because Vb increases to the opposite polarity of Va so that the second electrode 34 and the aluminum plate 3 are
It is considered that the electric field opposite to the electric field between the first electrode 33 and the aluminum plate becomes stronger between the first and second electrodes 33 and 2, and the electric charge generated by the discharge cannot be transported to the aluminum plate side.
Therefore, in order to charge an object to be charged using the charging device according to the present invention, one of the first electrode and the second electrode has a desired charging polarity (that is, it is desired to charge the object to be charged). Polarity), and the absolute value of the voltage is larger than that of the other electrode, and the substrate potential on which the charged object is placed must be smaller in absolute value than the electrode voltage having the large voltage absolute value. .

(Fourth Experiment) In this experiment, a potential difference is similarly applied between the first electrode 43 and the second electrode 44 by using the apparatus shown in FIG. Although measured, the charging device 41 used here is the first electrode 43.
A spacer 45 inserted between the second electrode 44 and the second electrode 44 projects toward the aluminum plate 42 side from the end faces of the electrodes on both sides. In the experiment using such a device, no current was observed to the aluminum plate 42. It is considered that this is because the protrusion of the spacer 45 lengthens the electric field path between the first electrode 43 and the second electrode 44, and strong discharge does not occur.

(Fifth Experiment) In this experiment, instead of the aluminum plate 22 in the apparatus shown in FIG. 3, the photosensitive drum 52 as shown in FIG. 11 is used.
Is arranged so as to face the charging device 51, the peripheral surface is actually charged, and the potential thereof is measured. In this experiment, the voltages applied to the first electrode 53 and the second electrode 54 are set in the following two ways. As shown in FIG. 12, according to the result of the above experiment, the peripheral surface of the photoconductor drum 52 is charged to a substantially saturated state by the first charging. Similar results can be obtained by applying alternating current to the electrodes.

(Sixth Experiment) In this experiment, instead of the photosensitive drum 52, a developing roll is arranged so as to face the charging device 51, and a thin layer of toner formed on the developing roll is charged. It was done. Also in this experiment, the voltage applied to the first electrode is two kinds of voltage, that is, the case of direct current and the case of superimposing alternating current on direct current, and the respective voltages are as follows.

The result of measuring the charge of the charged toner by the above experiment is as shown in FIG. 13. By using the charging device according to the present invention, the toner of the opposite polarity is eliminated, and most of the toner particles have the proper polarity. You can see that it is charged to. Then, it is understood that the width of the charge distribution of the toner particles is reduced by applying an alternating current to the electrodes so that the toner particles can be appropriately charged. Although the alternating current is superposed on the first electrode 53 in the above experiment, even if the alternating current is applied to the base material of the charged object, that is, the developing roll, similar results can be obtained by setting the respective average potentials to appropriate conditions. Is obtained.

[Second Embodiment] FIG. 14 is a schematic configuration diagram showing a charging device according to another embodiment of the invention described in claim 1, claim 2 or claim 3. This charging device 60 is formed by adhering a plurality of the charging devices shown in FIG. 1B in an overlapping manner and is a conductive member that is a power feeding member 64 and a second electrode 62 that are bonded to the back surface of the first electrode 61. The plate is also used to supply power to the discharge parts on both sides of the plate. That is, the first electrode 61 made of a semiconductive material is adhered to both sides of the power feeding member 64, and each of these faces the second electrode 62 via the spacer 63.
Further, the first electrode 61 is opposed to both sides of the second electrode 62a in the central portion via the spacer 63, and the one second electrode 62 and the first electrodes 61 on both sides are provided. A discharge is generated between them. In such a charging device, a plurality of discharge regions are provided in parallel, and it is possible to perform appropriate charging even when sufficient charging cannot be performed in one discharge region.

Next, an embodiment of the image forming apparatus according to the present invention will be described with reference to the drawings. 18a and 18b
FIG. 9 is a schematic view showing an image forming apparatus which is an embodiment of the invention described in claim 4, claim 5, claim 6 or claim 8 .
These image forming apparatuses are respectively shown in FIG.
Transfer device 123 in the image forming apparatus shown in FIG.
In place of 133, the charging device shown in FIG.
It was used as 0,230. Although the configuration and detailed operation of this charging device are duplicated, description thereof will be omitted. However, ions or electrons generated by the discharge between the first electrode 23 and the second electrode 24 are not connected to one of the electrodes and the image carrier 221.
The image receiving members 224 and 234 are charged by being moved according to the electric field formed between the image receiving member 231 and 231 and the toner image on the image bearing member is transferred to the image receiving member.

When a toner image was formed and transferred to the image receivers 224 and 234 by this image forming apparatus,
The image receptor was almost uniformly charged, and a clear image without blur and white spots in thin lines (FIG. 24 (b)) was obtained. Also,
It is obvious that the space occupied by the charging device as a transfer device is significantly smaller than the space occupied by the corotron type transfer device shown in FIG. 23 as compared with the device shown in FIG.

As the transfer device, the charging device shown in FIG. 7 or 14 can be used in place of the charging device shown in FIG. 3, and the charging device 60 as shown in FIG.
Since it is possible to mass-produce the charging device having a plurality of discharge parts by cutting the electrodes, the second electrodes, and the insulating spacers stacked in a plurality of stages, it is possible to simplify the manufacturing process and reduce the cost. effective.

Next, a description is given of an image forming apparatus according to an embodiment of the invention described in claim 7. This image forming apparatus uses the charging device shown in FIG. 15 as a transfer device instead of the transfer devices 220 and 230 in the image forming device having the configuration shown in FIG. Also in such an image forming apparatus, ions or electrons move from the charging device to the image carrier side, and the image receptor is efficiently charged.

The charging device 70 shown in FIG . 15 is made of a conductive material.
A plurality of cylindrical bodies 71 (first electrodes) made of
And a plurality of cylindrical bodies 72 (second electrodes) made of material
Well, these are arranged alternately on the substrate 73 and are adjacent to each other.
It is embedded so that the distance to the body is equal.
It Further, the end faces 71a and 72a are the same as the surface of the substrate 73.
They are aligned and face the object to be charged 74.
It In the cylindrical body 72 made of the semiconductive material,
A rod-shaped body 75 made of a conductive material is inserted into the core,
Is a power feeding member to the cylindrical body 72 that serves as the second electrode.
It Then, a predetermined potential is applied to this power supply member from the power source 77.
The conductive cylindrical body 71, which is the first electrode, is also electrically charged.
A predetermined potential is applied from the source 76. In this way the circle
Discharge occurs due to the potential difference applied between the pillars,
A charge is given to the charged object. In such a charging device 70, the columnar bodies to be the electrodes are arranged.
The range to be set is set arbitrarily, and evenly charged within that range
An electric charge can be given to an object.

In such an image forming apparatus, the first electrode and the second electrode of the charging device are divided into a plurality of pieces and are arranged in the width direction of the image receiving body or the support carrying the image receiving body. It is desirable to arrange them so as to face the image receptor or the support at a uniform interval, and thereby the charge amount of the image receptor will be uniform.

Further, as for the power supply member 75 to the resistor shown in FIG. 15A, the resistor 71 in the first electrode is also used.
Alternatively, from the side surface of the power feeding portion of the resistor 72 in the second electrode,
It is desirable that the distance through the resistor to the end faces 71a, 72a that generate the discharge is constant in the width direction of the image receptor or the support. In particular, the traveling speed of the image receptor is high and a large current value is required for charging. It's really important. This is because the charge supply to the discharge part is made constant, and for that purpose, the resistance from the power supply part to the discharge part needs to be constant.

Further, as a transfer device, FIG. 16 or FIG.
A charging device as shown in 7 may be used. This is billing
It is one embodiment of the invention described in Item 8 .

The charging device 80 shown in FIG .
The second electrode 82 made of a material is formed into a strip shape,
The conductive columnar body 81, which is an electrode, is connected to the strip-shaped second electrode.
They are arranged along the poles 82. And this cylindrical body 8
Interval between the first electrode made of 1 and the strip-shaped second electrode 82
Are equal. In such a charging device 80
Also has a cylindrical first electrode 81 and a strip-shaped second electrode 82.
A continuous discharge occurs between the
The charged object is transferred to the opposite charged object, and the charged object has a predetermined polarity.
Can be charged to.

The charging device 90 shown in FIG . 17 is an insulating base.
A thin metal layer and a coating layer made of a semiconductive material on the plate 96
To form a first electrode and a second electrode.
is there. This thin layer of metal 91, 92 is applied from both sides of the substrate
It is formed in the shape of teeth that alternate with the teeth of a comb.
The metal layer 91 protruding from the surface is a coating of a semiconductive material.
Covered by layer 93. Thin layer 92 of these metals
And the covering layer 93 covering the metal layer 91 are arranged in parallel at equal intervals.
And these are the second and first electrodes
It That is, this is the case for the coating layer 93 made of a semiconductive material.
A voltage is applied from a power supply 94 through the covering metal layer 91,
A voltage is applied from a power source 95 to the other thin metal layer 92.
The potential difference between these causes a continuous discharge
It is like this.

Even in such a charging device 90, the substrate
Ionization is caused by the discharge generated between the electrodes stacked on the 96
An object to be charged that has ions or electrons of a predetermined polarity facing each other
97, and the object to be charged on the opposite substrate is charged.
It

[0075]

As described above, in the charging device of the invention according to the present application, a continuous discharge is generated between the first electrode and the second electrode, which are arranged to face each other, and the electronic avalanche causes the discharge. Of the generated ions or electrons, only the polar ions or electrons to be charged are transferred by the electric field between the first or second electrode and the substrate supporting the object to be charged, and the object to be charged is charged. Give. Therefore, only the ions or electrons of a predetermined polarity can be brought close to the object to be charged and charged to the predetermined polarity. Therefore, even when the thinned toner is charged, the toner of the opposite polarity is not generated,
It is possible to appropriately charge the toner to a predetermined polarity. Further, the first electrode and the second electrode may be small ones, and since they are not in contact with each other and are opposed to each other with a small gap therebetween, they do not take place, and are not attached to any charged object. On the other hand, it can be applied to a small charging device that exhibits stable charging characteristics over a long period of time.

On the other hand, when used as a transfer device of an image forming apparatus, the transfer device can be brought into non-contact with the image receiving member or the image receiving member supporting member, so that adhesion and abrasion of foreign matter can be prevented, and further, Since miniaturization is possible, it is possible to suppress the adhesion of charges to the image receptor or the image receptor support before and after the transfer nip without lowering the transfer efficiency, and it is possible to efficiently obtain a clear and uniform image.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a charging device that is an embodiment of the invention described in claim 1, claim 2 or claim 3, and a schematic configuration diagram of a developing device in which the charging device is used.

FIG. 2 is a functional explanatory diagram of the charging device shown in FIG.

FIG. 3 is a schematic view showing a device of an experiment conducted to confirm the function of the charging device shown in FIG.

FIG. 4 is a diagram showing a result of an experiment performed using the apparatus shown in FIG. 3, showing a relationship between a potential difference between a first electrode and a second electrode and a current amount between them. It is a figure.

5 is a diagram showing the results of an experiment conducted using the apparatus shown in FIG. 3, showing the potential difference between the first electrode and the second electrode and the amount of charging current flowing to the charged object side. It is a figure which shows a relationship.

[Figure 6]
FIG. 4 is a diagram showing a result of an experiment conducted by using the apparatus shown in FIG. 3, and is a diagram showing a relationship between a distance between an electrode and an Al base and an amount of charging current flowing to the charged object side.

FIG. 7 is a schematic view showing another device of an experiment performed for confirming the function of the charging device shown in FIG.

8 is a diagram showing a result of an experiment performed using the apparatus shown in FIG. 7, showing a relationship between a distance between a first electrode and a second electrode and a charging current amount flowing to a charged object side. FIG.

9 is a diagram showing results of an experiment conducted using the apparatus shown in FIG. 7, which is a distance between the first electrode and the second electrode and an object to be charged, and a charging current flowing to the side of the object to be charged. It is a figure which shows the relationship with quantity.

FIG. 10 is a schematic view showing another device of an experiment performed for confirming the function of the charging device shown in FIG.

FIG. 11 is a schematic view showing another device of an experiment conducted for confirming the function of the charging device shown in FIG.

12 is a diagram showing a result of an experiment conducted by using the apparatus shown in FIG. 11, which is a diagram showing a potential of a charged photoconductor.

13 is a diagram showing a result of an experiment conducted using the apparatus shown in FIG. 11, showing a charge distribution of charged toner.

FIG. 14 is a schematic configuration diagram showing a charging device according to another embodiment of the invention described in claim 1, claim 2 or claim 3.

FIG. 15 is an image showing an embodiment of the invention according to claim 7;
A charging device used as a transfer device in an image forming apparatus.
It is a schematic block diagram which shows an arrangement.

FIG. 16 is an image showing an embodiment of the invention according to claim 8;
A charging device used as a transfer device in an image forming apparatus.
It is a schematic block diagram which shows an arrangement.

FIG. 17 is another embodiment of the invention according to claim 8;
Charging used as a transfer device in image forming devices
It is a schematic block diagram which shows an apparatus.

FIG. 18 Claim 4, Claim 5, Claim 6 or Claim 8
2 is a schematic configuration diagram of an image forming apparatus that is an embodiment of the invention described in FIG.

FIG. 19 is a schematic configuration diagram showing a conventionally known corona discharge device.

FIG. 20 is a schematic configuration diagram showing an example of a conventionally known developing device having a toner charging function.

21 is a schematic diagram illustrating a problem of the charging device used in the developing device shown in FIG.

22 is a diagram showing the charge density between the charge applying member and the developer carrying member in the charging device used in the developing device shown in FIG.

FIG. 23 is a schematic configuration diagram showing an example of an image forming apparatus using a conventional corona discharge device as a transfer device.

FIG. 24 is a diagram showing a problem in the image forming apparatus shown in FIG. 23.

FIG. 25 is an explanatory diagram showing another example of a conventional image forming apparatus.

[Explanation of symbols]

1 Image Carrier 2 Developing Device 3 Developing Roll 4 Power Supply 5 Charging Device 6, 7 Charging Device Power Supply 11 First Electrode 12 Second Electrode 13 Spacer 14 Power Supply Member 15 Insulating Member 21, 31, 41, 51 Charging device 22, 32, 42 Aluminum plate 23, 33, 43, 53 First electrode 24, 34, 44, 54 Second electrode 25 Ammeter 26, 36 Power supply member 27, 35, 45 Spacer 52 Photoconductor Drums 60, 70, 80, 90, 100, 200 Charging device 61 First electrode 62 Second electrode 63 Spacer 64 Power supply member 71 Cylinder body 72 made of conductive material Cylinder body 73 made of semi-conductive material 73 Substrate 81 conductive columnar body (first electrode) 82 second electrode 91 power supply member 92 metal layer (second electrode) 93 coating layer (first electrode) 121, 131, 221, 231 image bearing 122,132 discharge electrodes 123 and 133 corotron 124,134,224,234 receiving body 125,235 receiver member support 126, 136 power supply

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shota Oba 430 Nakai-cho, Ashigarakami-gun, Kanagawa Green Tech Nakakai Fuji Xerox Co., Ltd. (72) Inventor Shin-ichi Kuramoto 430 Nakai-cho, Ashigagami-gun, Kanagawa Green Tech Nakakai Fuji Xerox Co., Ltd. (56) Reference JP-A-4-365062 (JP, A) JP-A-8-315958 (JP, A) ) JP-A-6-110297 (JP, A) JP-A-5-181346 (JP, A) Actual Kaihei 2-107153 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 15/02 G03G 15/08 504 G03G 15/16 103

Claims (8)

(57) [Claims] 1. A charging device for providing an electric charge to an object to be charged, which is arranged close to and spaced from the object to be charged on a conductive base, and is a plate-shaped first electrode made of a resistor. A plate-shaped member made of a resistor or a conductor ,
Bonding with the first electrode and the interposition member made of an insulating material sandwiched between them
Second and an electrode, the end face of the became plate first electrode and a second electrode which is,
Both of them are arranged so as to face the base body, and the interposition member is a strip of the first electrode and the second electrode.
Charged object in the same plane as the end surface facing the electric object or from the end surface
A voltage is applied between the first electrode and the second electrode so that a continuous discharge is generated, and the first electrode or the second electrode Between the second electrode and the base body, ions or electrons having a charge of a polarity imparted to the object to be charged,
A charging device, wherein the electric potentials of the first electrode and the second electrode are set so that an electric field moving toward the substrate side is formed. 2. The charging device according to claim 1, wherein the end faces of the first electrode and the second electrode are closely opposed to a belt or a cylindrical body whose peripheral surface is supported so as to be capable of endless movement. A charging device, which is disposed and is supported in the width direction of the peripheral surface of the belt or the cylindrical body so as to face the peripheral surface at equal intervals. 3. The charging device according to claim 2, wherein a power feeding member made of a conductive material is bonded to a back surface of the first electrode, and the first electrode is a peripheral surface of the belt or the cylindrical body. A charging device having a uniform thickness in the width direction of the charging device. 4. A conductive base having an endless peripheral surface that is orbitally driven, and a dielectric layer or a photoconductor layer formed on the peripheral surface of the base, and a latent layer due to a difference in electrostatic potential. An image carrier on which an image is formed, a developing device for visualizing the latent image by adhering a developer to the latent image on the image carrier, and arranged to face the image carrier. An image forming apparatus having a transfer device for transferring a developer image to an image receiving body passing between the image carrier and the image carrier, wherein the transfer device is a plate-shaped first electrode made of a resistor, A plate-shaped member made of a resistor or a conductor ,
Bonding with the first electrode and the interposition member made of an insulating material sandwiched between them
Second and an electrode, the end face of the became plate first electrode and a second electrode which is,
Both of them are arranged so as to face the back surface of the image receptor, and the insertion member is a strip of the first electrode and the second electrode.
Charged object in the same plane as the end surface facing the electrical object or from the end surface
And has an end face in a retracted position with respect to the first electrode and the second electrode.
A voltage is applied to generate a discharge, and the first electrode or
Between the second electrode and the substrate
The substrate is provided with ions or electrons having a polar charge that imparts them.
The first electrode so that an electric field moving to the side is formed.
And each potential of the second electrode is set.
Image forming apparatus. 5. The image forming apparatus according to claim 4 , wherein the first electrode and the second electrode face the image carrier and are arranged in a width direction of an endless peripheral surface of the image carrier. An image forming apparatus, wherein the image forming apparatus is supported at equal intervals with the peripheral surface. 6. The image forming apparatus according to claim 5 , wherein a power feeding member made of a conductive material is adhered to the back surface of the first electrode, and the first electrode is an endless member of the image carrier. An image forming apparatus having a uniform peripheral surface width. 7. An endless peripheral surface that is orbitally driven.
Conductive substrate and dielectric formed on the peripheral surface of the substrate
Layer or a photoreceptor layer, the latent image due to the difference in electrostatic potential is
The latent image can be formed by attaching a developer to the image carrier formed on the peripheral surface and the latent image on the image carrier.
Between the developing device to be visualized and the image carrier, which is arranged so as to face the image carrier.
A transfer device that transfers the developer image to the image receptor that passes through
In the image forming apparatus, the transfer device is made of a resistor, and is provided on a substrate in a plurality of divisions.
The first electrode is arranged at intervals and a resistor or a conductor, and is divided into a plurality of parts on the substrate.
Are provided and divided, and each of them is the same as the first electrode.
A second electrode arranged so as to be at a distance, and that of a divided portion of the first electrode and the second electrode.
Each of them should penetrate the substrate from the back side to the front side.
A cylindrical body provided, the cylindrical body of the second electrode comprising the first electrode and the resistor
A conductive power feeding member is inserted inside from the back side.
Between the first electrode and the second electrode
A voltage is applied to generate a discharge, and the first electrode or
Between the second electrode and the substrate
Ions or electrons having a polar charge imparting the
So that an electric field moving to the side is formed.
And the potentials of the second electrode are set.
Image forming apparatus. 8. An endless peripheral surface which is orbitally driven.
Conductive substrate and dielectric formed on the peripheral surface of the substrate
Layer or a photoreceptor layer, the latent image due to the difference in electrostatic potential is
The latent image can be formed by attaching a developer to the image carrier formed on the peripheral surface and the latent image on the image carrier.
Between the developing device to be visualized and the image carrier, which is arranged so as to face the image carrier.
A transfer device that transfers the developer image to the image receptor that passes through
In the image forming apparatus, the transfer device is made of a resistor and is arranged so as to face the base body.
It is composed of a first electrode and a resistor or conductor, and faces the substrate.
Also, they are arranged side by side so as to be in close contact with the first electrode in a non-contact manner.
A second electrode disposed between the first electrode and the second electrode.
A DC voltage is applied so that discharge occurs, and the first voltage is applied.
Between the electrode or the second electrode and the substrate, the image receiving
Ions or electrons that have a polar charge imparted to the body,
The first electric field is formed so that an electric field moving toward the substrate side is formed.
Characterized in that the potentials of the pole and the second electrode are set
Image forming apparatus.