JP2003015419A - Developing device and image forming device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming device equipped therewith capable of forming a stable image by making toner softly land on a photoreceptor drum without scattering the toner in the case of utilizing a mechanism (electric field curtain) for carrying the toner by using traveling wave electric field. SOLUTION: The carrying direction H of the toner T is regulated to the same as the rotating direction K of the photoreceptor drum 1 moving an electrostatic latent image in a peripheral direction. Applied voltage Vpp (V) to a progressive wave generating electrode 41b and a pitch λ (m) between the respective progressive wave generating electrodes are set to satisfy relation 1<=Vpp/λ<=6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for developing an electrostatic latent image formed on a latent image bearing member (image bearing member) with a developer or the like, and an image forming apparatus including the developing device. The present invention relates to a device that uses a mechanism (electric field curtain) that conveys a developer using a traveling wave electric field.

Further, the electrostatic latent image is not only the one in which optical information is written on an image carrier charged with a predetermined charge, but also an electrostatic charge is directly charged on a dielectric like an ion flow system. An electrostatic image is formed in the space by applying an arbitrary voltage to the one that forms a latent image or to the electrode that has a plurality of openings like the toner jet method, and the developer is directly ejected onto the recording medium. It is also applicable to those that perform image formation.

[0003]

2. Description of the Related Art As a developing apparatus applied to an image forming apparatus using an electrophotographic process such as a copying machine, a printer, a facsimile, etc., at present, a non-developing apparatus which does not contact a developing agent carrier with an image carrier is used. A contact-type developing device is drawing attention, and a method using a powder cloud method, a jumping method, or an electric field curtain (traveling wave electric field) has been proposed.

As a means for generating an electric field curtain, for example, as disclosed in Japanese Patent Laid-Open No. 9-68864, a supporting base material made of metal or resin,
An insulating layer laminated on the supporting base material is provided, and a plurality of electrodes are sequentially embedded in the insulating layer, with three electrodes for generating an electric field curtain function as one group. The developer is carried on the surface of the developer carrying member by a traveling wave electric field formed by applying a multiphase voltage to each electrode.

[0005]

By the way, in the developing device utilizing the traveling wave electric field, the developer is conveyed in a predetermined direction on the developer conveying member. In that case, if the developer conveying direction is the opposite direction (counter direction) to the moving direction of the image carrier that moves the electrostatic latent image in the circumferential direction, the developer moves in the developing area with respect to the image carrier. The speed becomes relatively faster than the moving speed of the image carrier. For this reason, the collision energy when the developer lands on the image bearing member becomes large, and when the developer lands on the portion where the developer is already present on the image bearing member, the scattering of the developer occurs. It may occur and adversely affect the image.

Moreover, in such a developing device,
The applied voltage applied to each electrode is increased in order to increase the amount of developer transported on the developer transport member and to reduce the sticking occurrence rate of the developer. Even in this case, if the developer transport direction is the counter direction with respect to the moving direction of the image carrier, the developer transport speed increases due to an increase in the voltage applied to each electrode, so that the development in the developing area is performed. The speed at which the agent moves becomes relatively faster than the speed at which the image carrier moves, which makes it more difficult for the developer to land on the image carrier and frequently causes splattering, which is a factor that adversely affects the image. Becomes

The present invention has been made in view of the above points, and an object of the present invention is to perform a soft landing without scattering a developer on an image carrier to form a stable image. It is an object of the present invention to provide a developing device and an image forming apparatus including the developing device.

[0008]

In order to achieve the above object, in the present invention, an electrostatic latent image is arranged in a developing area opposite to an image bearing member bearing on its surface, and a predetermined amount is formed on a substrate. A developer transport member is formed by covering a plurality of electrodes arranged at intervals with a surface protective layer, and the developer is transported on the developer transport member by a traveling wave electric field formed by applying a multiphase voltage to each electrode. It is premised on a developing device that is transported by. Further, the carrying direction of the developer is defined as the same direction as the moving direction of the image carrier that moves the electrostatic latent image in the circumferential direction.

Due to this specific matter, the developer carrying direction becomes the same direction (with direction) as the moving direction of the image carrier for moving the electrostatic latent image in the circumferential direction, and the development in the developing area with respect to the image carrier is carried out. The moving speed of the agent becomes slower than the moving speed of the image carrier. For this reason, the collision energy when the developer lands on the image carrier becomes small, and even if the developer lands on the portion where the developer already exists on the image carrier, Scattering does not occur, and it is possible to form a stable image without adversely affecting the image.

In addition, even if the applied voltage applied to each electrode is increased in order to increase the amount of developer transported on the developer transport member and to reduce the sticking rate of developer, the development is performed. By making the developer conveying direction the with direction with respect to the moving direction of the image carrier, even if the developer conveying speed is increased by the increase of the voltage applied to each electrode, the development in the developing area is performed. The moving speed of the agent becomes relatively slower than the moving speed of the image carrier, the developer can be softly landed on the image carrier, and the scattering of the developer can be prevented.
It is possible to form a stable image.

Particularly, the applied voltage Vpp (V) applied to each electrode and the inter-electrode pitch λ (m) of each electrode are set so as to satisfy the relationship of 1 ≦ Vpp / λ ≦ 6. In this case, the relationship between the applied voltage Vpp and the interelectrode pitch λ is set to the optimum condition.

That is, the applied voltage Vpp and the electrode pitch λ
If the relationship (Vpp / λ) with is smaller than 1, the amount of developer conveyed is small, and the developer is often fixed, and the developer conveyability is very poor. In that case, as the value of Vpp / λ becomes larger than 1, the transport amount of the developer increases and the amount of occurrence of sticking of the developer also decreases. However, if the value of Vpp / λ is larger than 6, the interelectrode pitch λ becomes relatively small with respect to the applied voltage Vpp, and there is a risk that leakage may occur between adjacent electrodes.

Therefore, by setting the applied voltage Vpp and the interelectrode pitch λ so as to satisfy the relationship of 1 ≦ Vpp / λ ≦ 6, a sufficient amount of the developer can be carried to obtain a sufficient density and the developer can be obtained. It is possible to form a stable image with less scattering.

Further, when the above-mentioned developing device is provided in the image forming apparatus, the developing device capable of forming a stable image without scattering the developer on the image carrier and the image forming apparatus including the developing device. Can be provided.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
1 shows an image forming apparatus including a developing device according to the embodiment of the present invention. Inside the image forming apparatus X, a cylindrical photosensitive drum 1 as an image carrier is provided. Around the photosensitive drum 1, a charging member 2, an exposure member 3, a developing device 4, a transfer member 5, a cleaning member 6, and a charge removing member 7 are sequentially arranged around the photosensitive drum 1. Further, between the photoconductor drum 1 and the transfer member 5, a paper transport path for transporting the paper P is provided. A fixing device 8 including a pair of upper and lower fixing rollers 81, 81 is arranged on the downstream side of the photosensitive drum 1 when viewed from the conveying direction of the sheet conveying path.

In the electrophotographic process, an original image or an electrostatic latent image corresponding to data from a host computer (not shown) is formed on the photosensitive drum 1, and the electrostatic latent image is visualized by a developing device. The image is formed by being transferred onto the sheet P.

The photoconductor drum 1 has a photoconductive layer 12 formed on a base material 11, and comprises a charging member 2 to the above-mentioned members 3 to 3.
It is rotatable according to the arrangement order of 7. First, the surface (photoconductive layer 12) of the photosensitive drum 1 is charged by the charging member 2 until it reaches a predetermined potential. The surface of the photoconductor drum 1 charged to a predetermined potential reaches the position of the exposure member 3 by the rotation of the photoconductor drum 1. The exposure member 3 is a writing unit that writes an image on the surface of the photosensitive drum 1 which is charged by light such as a laser, based on image information. As a result, an electrostatic latent image is formed on the photosensitive drum 1. The surface of the photoconductor drum 1 on which the electrostatic latent image is formed reaches the position of the developing device 4 by the rotation of the photoconductor drum 1.

In the developing device 4, the electrostatic latent image on the surface of the photosensitive drum 1 is developed as a toner image by the toner T (developer) conveyed on the toner conveying member 41. The surface of the photosensitive drum 1 carrying the toner image reaches the position of the transfer member 5 by the rotation of the photosensitive drum 1.

The transfer member 5 transfers the toner image on the surface of the photosensitive drum 1 onto the paper P. The toner image transferred from the photosensitive drum 1 onto the paper P is fixed onto the paper P by the fixing device 8.

Photoreceptor drum 1 after the toner image is transferred
The surface of the photosensitive drum 1 reaches the position of the cleaning member 6 by the rotation of the photosensitive drum 1. Cleaning member 6
Removes the toner T, paper dust, etc. remaining on the surface of the photosensitive drum 1. The surface of the photoconductor drum 1 cleaned by the cleaning member 6 reaches the position of the charge removing member 7 by the rotation of the photoconductor drum 1. The charge removing member 7 removes the electric potential remaining on the surface of the photosensitive drum 1. One image formation is completed by the series of operations described above.

As the photosensitive drum 1, for example,
A metal drum such as aluminum is used as a base material 11, and a photoconductive layer 12 such as amorphous silicon (a-Si), selenium (Se) or an organic optical semiconductor (OPC) is provided on the outer peripheral surface thereof.
Although a structure in which is formed into a thin film is mentioned, it is not particularly limited.

Examples of the charging member 2 include a charging wire such as a tungsten wire, a corona charger including a metal shield plate, a grid plate, a charging roller, a charging brush, and the like, but are not particularly limited thereto. Not a thing.

Examples of the exposing member 3 include, but are not limited to, semiconductor lasers and light emitting diodes.

Examples of the transfer member 5 include, but are not limited to, a corona transfer device, a transfer roller, and a transfer brush.

Examples of the cleaning member 6 include a cleaning blade, but are not particularly limited.

Examples of the charge removing member 7 include a charge removing lamp and the like, but are not particularly limited.

In this embodiment, a constant space is provided between the toner conveying member 41 and the photosensitive drum 1, and the electrostatic latent image on the surface of the photosensitive drum 1 is developed in a non-contact manner. However, the present invention is not limited to this,
A configuration may be employed in which the toner transport member and the surface of the photosensitive drum are brought into contact with each other to perform contact development.

As shown in FIG. 2, the developing device 4 includes a casing 40, a toner conveying member 41, and a mixing paddle 42. The casing 40 accommodates the toner T therein. The mixing paddle 42 is for mixing the toner T contained in the casing 40.

The toner conveying member 41 has a belt shape so as to face the developing area A of the photosensitive drum 1 and form a substantially flat surface. In this embodiment, the belt-shaped toner conveying member 41 is shown, but the shape of the toner conveying member 41 is not limited to this, and may be, for example, a semi-circular shape.

The toner conveying member 41 is connected to the developing device 4
Is slightly inclined with respect to the up-down direction and is substantially parallel to the tangent line of the developing area A on the surface of the photosensitive drum 1. Further, a supporting member 43 for holding the toner conveying member 41 is provided on the surface opposite to the surface for conveying the toner T so that the belt-shaped toner conveying member 41 can maintain the above arrangement.

At the lower end of the toner conveying member 41, a supply member 44 for supplying the toner T conveyed on the surface of the toner conveying member 41 is provided. On the other hand, at the upper end portion of the toner conveying member 41, the toner conveying member 4
A collecting member 45 for collecting the toner T on the surface of No. 1 is provided.

A multi-phase AC power source 47 and a developing bias power source 48 are connected in series to the toner conveying member 41. The supply member 44 and the recovery member 45 each have, for example, a cylindrical shape and are rotatably in contact with the surface of the belt-shaped toner conveying member 41.

The supply member 44 is for supplying the toner T housed in the casing 40 to the toner conveying member 41, and the material thereof is not particularly limited, but, for example, silicone or urethane. , EP
Solid rubber such as DM (ethylene-propylene-diene-methylene copolymer), foamed rubber and the like can be mentioned.
Further, conductivity may be imparted by adding carbon black or an ion conductive agent (voltage application is also possible).
The contact pressure between the supply member 44 and the toner conveying member 41 or the voltage value applied to the supply member 44 may be set to an appropriate value to add the function of charging the toner T to the supply member 44. Alternatively, in the front stage of the supply member 44,
For example, a thin plate blade (the same material as the supply member 44 can be used as the material) may be provided to charge the toner.

The collecting member 45 collects the toner T that does not contribute to the development of the electrostatic latent image on the photosensitive drum 1 and returns it to the developing device 4, and its material is not particularly limited. However, for example, the same material as the supply member 44 can be used.

The supporting member 43 is for holding the belt-shaped toner conveying member 41 in a state of facing the developing area A of the photosensitive drum 1, and its structure is not particularly limited. For example, ABS (Acryloni
trile-Butadiene-Styrene (acrylonitrile butadiene styrene) resin and the like.

The toner conveying member 41 conveys the toner T by an electric field curtain action, and as shown in FIG. 3, a traveling wave generating electrode for generating an electric field curtain action on a base material 41a made of an insulating layer. A plurality of sets 41b, ... Are sequentially arranged, with four sets as one set. The surface side of the toner transport member 41 is covered with an insulating layer 41c. The surface of the insulating layer 41c is covered with the surface protection layer 41d. Then, a polyphase AC voltage is applied to these electrodes 41b, ... From a polyphase AC power supply 47 for toner conveyance, so that an electric field curtain is generated on the surface of the toner conveyance member 41 in a direction parallel to it. As a result, the toner T is conveyed to the developing area A by the electric field curtain action. In this case, each traveling wave generating electrode 41b has a width of 40 μm.
It is a micro electrode of ~ 250μm, and this is 50dp.
i (dot per inch) to 300 dpi, that is, they are arranged in parallel with each other with a pitch of about 500 μm to 85 μm.

Specific examples of the toner conveying member 41 include, for example, base material 41a: polyimide (thickness: 25 μm).
m), traveling wave generating electrode 41b: copper (thickness 18 μm), insulating layer 41c: polyimide (thickness 25 μm). In the present embodiment, four traveling wave generating electrodes 41b, ... Are set as one set, and four phases of voltage waveforms as shown in FIG. Is applied to form the traveling wave electric field on the traveling wave generating electrodes 41b, ..., However, the invention is not particularly limited to this, and three traveling wave generating electrodes are used as one set to form a three-phase electric field. Alternating voltage may be applied.
Further, it is preferable that a bias voltage (developing bias) is applied so that a developing electric field is formed between the photoconductor drum 1 and the toner conveying member 41. The material of the surface protection layer 41d is an organic insulating material such as polyimide, PET (polyethylene terephthalate), polytetrafluoroethylene, polyfluoroethylene propylene, PTFE (polytetrafluoroethylene), or silicon, isoprene, butadiene, or the like. Examples of the rubber material include carbon black and an ionic conductive material dispersed or compatible with each other.

The voltage waveform may be a sine wave, a rectangular wave, a trapezoidal wave or the like, and the range of the voltage value is, for example, about 100 V to 3 kV so that dielectric breakdown does not occur between the traveling wave generating electrodes 41b and 41b. As the frequency range, 100 Hz to 5 kHz is preferably used. However, these voltage values and frequencies are not particularly limited as long as appropriate values may be set depending on the shape of the traveling wave generating electrode element, the transport speed of the toner T, the material used for the toner T, and the like.

As a characteristic part of the present invention, as shown in FIG. 5, on the toner conveying member 41 (surface protective layer 4).
The conveying direction of the toner T (on the surface of 1d) (indicated by an arrow H in the figure) is the rotation direction of the photosensitive drum 1 (in the counterclockwise direction indicated by an arrow K in the figure) that moves the electrostatic latent image in the circumferential direction. Direction). Here, when the rotation speed K1 (mm / s) of the photosensitive drum 1 and the transport speed H1 (mm / s) of the toner T are set, the relative speed F of the photosensitive drum 1 to the toner T is K1- H
It becomes 1 (mm / s). For example, if the rotation speed K1 of the photosensitive drum 1 is 200 (mm / s) and the transport speed H1 of the toner T is 300 (mm / s), the photosensitive drum 1
The relative speed F (relative speed) of the toner to the toner T is 10
It becomes 0 (mm / s).

As a result, the conveying direction H of the toner T is in the same direction (with direction) as the rotation direction K of the photosensitive drum 1 for moving the electrostatic latent image in the circumferential direction, and the developing area A for the photosensitive drum 1 is formed. The moving speed of the toner T becomes slower than the rotating speed of the photosensitive drum 1. For this reason, the collision energy when the toner T lands on the photosensitive drum 1 becomes small, and even if the toner T lands on the portion where the toner T is already present on the photosensitive drum 1, the toner T T scattering does not occur, and it is possible to form a stable image without adversely affecting the image.

In this case, in order to increase the carry amount of the toner T on the toner carrying member 41 and to reduce the sticking occurrence rate of the toner T, the applied voltage applied to each traveling wave generating electrode 41b is increased. Even if the toner T is conveyed, the conveying direction H of the toner T is set to the with direction with respect to the rotating direction K of the photosensitive drum 1, so that the conveying speed of the toner T is increased by the increase of the voltage applied to each traveling wave generating electrode 41b. Despite this, the moving speed (conveying speed) of the toner T in the developing area A becomes relatively slower than the moving speed (rotational speed) of the photosensitive drum 1, and the toner T relative to the photosensitive drum 1 moves. The landing can be done softly, preventing the toner T from scattering,
It is possible to form a stable image.

The applied voltage Vpp (V) applied to each traveling wave generating electrode 41b and the interelectrode pitch λ (m) of each traveling wave generating electrode 41b are 1≤Vpp / λ≤6. Are set to satisfy the relationship.

As a result, the relationship between the applied voltage Vpp and the interelectrode pitch λ is set to the optimum condition.

That is, in the dot reproduction evaluation shown in FIG. 6, the relationship between the applied voltage Vpp and the interelectrode pitch λ (Vpp
When / λ) is 0.5 which is smaller than 1, the amount of toner T conveyed is small, and the presence of toner T sticking is often observed.
The transportability of the toner T is extremely poor in both counter rotation and with rotation. In that case, as the value of Vpp / λ becomes larger than 1, the transport amount of the toner T increases, and the amount of toner T sticking also decreases. However, if the value of Vpp / λ is larger than 6, the inter-electrode pitch λ becomes relatively small with respect to the applied voltage Vpp, and there is a risk that leakage may occur between the adjacent traveling wave generating electrodes 41b and 41b. In addition, the result of FIG.
It is based on the experimental conditions shown in Table 1 below.

[0046]

[Table 1] Regarding dot scattering, as shown in (a) of FIG. 7, the case where stable dots are formed is represented by “⊚”, and as shown in (b) and (c) of FIG.
As a result of scattering due to the collision of the toner T, and "○" to "x" as the image is disturbed, as shown in FIG. 6, both the counter rotation and the with rotation were stable as the value of Vpp / λ was smaller. Although image formation was obtained, it was revealed that stable image formation was obtained up to the point where the value of Vpp / λ was larger in the with rotation.

Therefore, as shown in FIG. 6, from the comprehensive judgment showing the comprehensive evaluation with respect to the evaluation of the transportability of the toner T and the scattering of the dots, 1 is set in the with rotation.
Applied voltage Vpp so as to satisfy the relationship of ≦ Vpp / λ ≦ 6
And the pitch λ between the electrodes are set, a sufficient toner T
It is possible to form a stable image with a sufficient density by the conveyance amount of, and with less scattering of the toner T.

Further, by providing the image forming apparatus X with such a developing device 4, it is possible to provide the image forming apparatus X which can form a stable image without scattering the toner T on the photosensitive drum 1. it can.

<Second Embodiment> Next, the second embodiment of the present invention will be described.
The embodiment will be described with reference to FIGS. 8 and 9.

In this embodiment, the developing device is provided with an endless belt as a surface protection layer which is driven on the toner conveying member (on the surface of the insulating layer) at a slight speed in the toner conveying direction. The rest of the configuration except the endless belt is the same as that of the first embodiment, and the same parts are denoted by the same reference numerals and the description thereof is omitted.

That is, in the present embodiment, as shown in FIG. 8, the endless belt 9 is provided on the surface of the toner conveying member 41 (the surface facing the photosensitive drum 1) so as to cover the surface in the circumferential direction. Has been. The endless belt 9 is driven at a predetermined peripheral speed by a driving roller 91 provided inside the casing 40 of the developing device 4. In this way, by driving the endless belt 9 at a predetermined peripheral speed, the surface of the toner conveying member 41 is constantly renewed, and charging and toner T adhesion on this surface are prevented.
The driving speed of the endless belt 9 is preferably slow enough to be considered to be substantially stationary with respect to the transport speed of the toner T, and is 1/10 to 100 of the transport speed of the toner T. It is set to about one-third.
In this case, the driving speed of the endless belt 9 can be measured by, for example, providing two infrared sensors and detecting the arrival time of the toner T in each, or by using a high-speed video camera.

Further, a constant tension is applied to the endless belt 9 so as to be in close contact with the surface of the toner conveying member 41, and the traveling wave formed by the traveling wave generating electrode 41b is formed on the surface. The electric field (electric field curtain) acts uniformly. As the endless belt 9, an organic insulating material such as polyimide, PET (polyethylene terephthalate), polytetrafluoroethylene, polyfluoroethylene propylene, PTFE (polytetrafluoroethylene), or a rubber material such as silicon, isoprene, or butadiene is used. Applied. And the endless belt 9
The thickness depends on the pitch between the electrodes of the toner conveying member 41, but is 5 μm to 200 μm, preferably 10 μm to 100 μm.
μm is preferred. Further, as the driving roller 91, S
A metal roller member made of US or iron or a metal roller member having a cored bar covered with a member such as rubber, film or sponge is used. Further, on the back side of the toner conveying member 41, outside the endless belt 9 facing the toner T in the casing 40 (right side in FIGS. 8 and 9),
A substantially arc-shaped toner wall 93 that prevents direct contact with the toner T in the casing 40 is provided.

The toner T conveyed on the surface of the endless belt 9 is supplied by the supply member 44, while the toner T on the surface of the endless belt 9 is collected by the collecting member 45. Then, each traveling wave generation electrode 41
By applying a multi-phase AC voltage from the multi-phase AC power source 47 to b, ..., An electric field curtain is generated on the endless belt 9 in a direction parallel to the electric field curtain. The toner T is conveyed. In this case, when the toner T adheres on the surface of the toner conveying member 41, the toner conveying member 41
Since the endless belt 9 that is driven at a slow speed moves on the surface of the toner, even if the toner T stops being conveyed in the region directly above the toner conveying member 41, the toner T is conveyed by the endless belt 9 to a region having a strong electric field strength. The conveyance is restarted, and the toner T is smoothly conveyed.

As shown in FIG. 9, the driving direction of the endless belt 9 driven on the toner conveying member 41 (counterclockwise direction indicated by arrow V in the figure) is the toner T on the endless belt 9. Is defined to be the same as the conveying direction (indicated by an arrow H in the figure) and the rotation direction of the photosensitive drum 1 (counterclockwise direction indicated by an arrow K in the figure).

As a result, the conveying direction H of the toner T becomes the same direction (wiz direction) as the driving direction V of the endless belt 9 and the rotation direction K of the photosensitive drum 1, and in the developing area A for the photosensitive drum 1. The moving speed of the toner T on the endless belt 9 becomes relatively slower than the rotating speed of the photosensitive drum 1. For this reason, the collision energy when the toner T lands on the photosensitive drum 1 becomes small, and even if the toner T lands on the portion where the toner T is already present on the photosensitive drum 1, the toner T T scattering does not occur, and it is possible to form a stable image without adversely affecting the image.

The applied voltage Vpp (V) applied to each traveling wave generating electrode 41b and the inter-electrode pitch λ (m) of each traveling wave generating electrode 41b are 1 ≦ Vpp / λ.
By setting so as to satisfy the relationship of ≦ 6, a sufficient density can be obtained with a sufficient transport amount of the toner T,
In addition, it is possible to form a stable image with less scattering of the toner T.

It should be noted that the present invention is not limited to the electrostatic latent image in which optical information is written on the photosensitive drum charged with a predetermined charge as described in the above embodiments. , Such as the ion flow method, which directly forms an electrostatic latent image on a dielectric, or the toner jet method, which applies an arbitrary voltage to an electrode having a plurality of openings, electrostatically discharges the space. It can also be applied to a device that directly forms an image by forming an electric image and flying a developer onto a recording medium.

[0058]

As described above, by setting the carrying direction of the developer to be the width direction with respect to the moving direction of the image carrier, the moving speed of the developer in the developing area relative to the image carrier can be changed. By making it relatively slower than the speed, the collision energy of the developer at the time of landing on the image carrier can be made small, and a stable image can be formed without adversely affecting the image due to the scattering of the developer. Moreover, even though the developer transport speed is increased by increasing the voltage applied to each electrode, the developer moving speed in the developing area is set relatively slow with respect to the image carrier moving speed. , Landing the developer on the image carrier softly to prevent scattering of the developer,
A stable image can be formed.

Particularly, by setting the value Vpp / λ obtained by dividing the voltage Vpp applied to each electrode by the inter-electrode pitch λ (m) to be greater than 1 and 6 or less, a sufficient developer transport amount can be obtained. It is possible to obtain a density and form a stable image with less scattering of the developer.

Further, by providing the image forming apparatus with such a developing device, a developing device capable of forming a stable image without scattering the developer on the image carrier and an image forming apparatus equipped with the developing device are provided. can do.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a schematic configuration of an electrophotographic image forming apparatus to which a developing device according to a first embodiment of the present invention is applied.

FIG. 2 is a schematic diagram showing a configuration of the developing device.

FIG. 3 is a schematic diagram showing a structure of a toner conveying member.

FIG. 4 is a waveform diagram showing a voltage waveform applied to the toner conveying member.

FIG. 5 is an enlarged view showing a toner transport state on the toner transport member.

FIG. 6 is a diagram showing a determination result which is a proof when defining the range of the value Vpp / λ obtained by dividing the voltage Vpp applied to each electrode by the inter-electrode pitch λ.

FIG. 7A is a diagram showing a state in which dots that are stable with respect to dot scattering are formed. FIG. 7B is a diagram showing a state in which the dots are slightly scattered and the image is slightly disturbed. FIG. 7C is a diagram showing a state in which dots are considerably scattered and the image is disturbed.

FIG. 8 is a schematic diagram showing a configuration of a developing device according to a second embodiment of the present invention.

FIG. 9 is an enlarged view showing a toner transport state on the toner transport member.

[Explanation of symbols]

1 Photoconductor drum (image carrier) 4 Developing device 41 Toner Transport Member (Developer Transport Member) 41a base material 41b Traveling wave generating electrode (electrode) 41d surface protection layer 9 Endless belt (surface protection layer) A development area Vpp applied voltage λ Electrode pitch T toner (developer) X image forming device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Taisuke Uemura             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Kiyoshi Toizumi             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Toshimitsu Goto             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F term (reference) 2H077 AB03 AB14 AC04 AC13 AC16                       AD07 AD31 AD36 DB08 DB14                       EA16

Claims (3)

[Claims] 1. An electrostatic latent image is arranged in a developing area facing an image carrier that carries the electrostatic latent image, and a plurality of electrodes arranged at a predetermined interval on a base material are covered with a surface protective layer. In the developing device, the developer transporting member is configured to transport the developer on the developer transporting member by a traveling wave electric field formed by applying a multiphase voltage to each electrode. Are defined in the same direction as the moving direction of the image carrier that moves the electrostatic latent image in the circumferential direction. 2. The developing device according to claim 1, wherein the applied voltage Vpp (V) applied to each electrode and the interelectrode pitch λ (m) of each electrode are 1 ≦ Vpp / A developing device, which is set so as to satisfy the relationship of λ ≦ 6. 3. An image forming apparatus comprising the developing device according to claim 1 or 2.