JP4094482B2 - Developing device and image forming apparatus having the same - Google Patents

Description

したがって、上記実施形態では、各進行波発生電極４１ｂによるトナーＴの搬送方向Ｖが無端ベルト１０１の移動方向Ｃに対し５゜傾斜しているので、無端ベルト１０１上の固着トナーは、各進行波発生電極４１ｂによるトナーＴの搬送方向Ｖから見て、見かけ上横へずれてゆくために、トナーＴの進行方向を妨げる時間が短くなり、『白抜け』が低減することになる。そのため、無端ベルト１０１上に固着トナーが発生しても、現像に影響を与えずに良好な現像を行うことができる。
【００６７】
また、各進行波発生電極４１ｂが、トナーＴが搬送される全ての領域（トナー搬送領域Ｈ，Ｈ及び現像領域Ｇ）においてそれぞれ同一角度（無端ベルト１０１の移動方向Ｃと直交する直交線Ｋに対し所定角度θずつ傾斜した状態）で等間隔に配置されているので、トナー搬送領域Ｈ，Ｈ及び現像領域ＧにおいてトナーＴの飛翔状態を異ならせることなく安定したトナー搬送を行うことができる。
【００６８】
そして、トナー搬送方向最上流側の進行波発生電極４１ｂが、無端ベルト１０１に対するトナー供給部材４４の接触部位４４Ｘよりも下流側でかつ現像領域Ｇよりも上流側に配されているので、トナーＴの搬送が開始されるトナー搬送方向最上流側の進行波発生電極４１ｂがトナー供給部材４４との接触部位４４Ｘよりも上流側にあるもののように無端ベルト上の同じ場所でトナー搬送とトナー供給とが行われることがなく、トナー供給時に制御すべきトナー層の乱れを防止することができる。しかも、トナー搬送方向最上流側の進行波発生電極４１ｂが現像領域Ｇよりも下流側にあるもののように無端ベルト上の固着トナーが発生している部分でトナー搬送が行われないことがなく、トナーＴによる現像を円滑に行うことができる。
【００６９】
また、各進行波発生電極４１ｂが無端ベルト１０１の移動方向Ｃに対し直交する直交線Ｋに対しそれぞれ５°傾斜して配されているので、無端ベルト１０１上に固着トナーが発生した際に『白抜け』により現像に影響を与えずに良好な現像を行わせつつ、各進行波発生電極４１ｂによるトナーＴの搬送方向Ｖと無端ベルト１０１の移動方向Ｃとの互いの角度差による現像装置４の大型化を効果的に抑制することができる。
【００７０】
更に、上述した現像装置４を画像形成装置Ｘに備えていることによって、無端ベルト１０１上に発生した固着トナーによって現像に影響を与えずに良好な現像を行い得る画像形成装置Ｘを提供することができる。
【００７１】
なお、本発明は、上記実施形態に限定されるものではなく、その他種々の変形例を包含している。例えば、上記実施形態では、各進行波発生電極４１ｂによるトナーＴの搬送方向Ｖを無端ベルト１０１の移動方向Ｃに対し５゜傾斜させたが、無端ベルトの移動方向が各進行波発生電極によるトナーの搬送方向に対し５゜傾斜させるようにしてもよく、この場合においても同様の作用・効果が得られる。
【００７２】
また、各進行波発生電極によるトナーの搬送方向と無端ベルトの移動方向とは、互いに３°以上ないし２０°以下の角度範囲内で異なっていれば何度傾斜させていてもよく、この場合には、無端ベルト上に固着トナーが発生しても、『白抜け』によって現像に影響を与えずに良好な現像を行いつつ、各進行波発生電極によるトナーの搬送方向とベルト部材の移動方向との互いの角度差による現像装置の大型化を可及的に抑制することができることになる。そして、各進行波発生電極によるトナーの搬送方向と無端ベルトの移動方向とが互いに２０°以上異なっていると、『白抜け』の低減効果に殆ど変化がなくなる上（『白抜け』低減効果と角度差との関係は、固着トナーの大きさに関わると推測される）、傾斜角度を大きくすれば、ベルト送り方向におけるトナー搬送部材の長さが大きくなって、昨今の現像装置の小型化の流れに逆行することから、傾斜角を大きくすることは好ましくない。
【００７３】
【発明の効果】
以上のように、トナー搬送部材の表面上において進行波電界によりトナーを搬送する各電極のトナー搬送方向と、トナー搬送部材の表面上においてトナー搬送方向に微速移動するベルト部材の移動方向とを、互いに所定角度異ならせることで、各電極によるトナーの搬送方向から見てベルト部材上の固着トナーを見かけ上横へずれさせてトナーの進行方向を妨げる時間を短くし、『白抜け』を低減させているため、ベルト部材上の固着トナーの存在如何に係わらず現像に影響を与えさせずに良好な現像を行うことができる。
【図面の簡単な説明】
【図１】本発明の実施形態に係わる現像装置が適用される電子写真方式を用いた画像形成装置の概略構成を示す模式図である。
【図２】現像装置の構成を示す模式図である。
【図３】トナー搬送部材の構成を示す模式図である。
【図４】トナー搬送部材に印加される電圧波形を示す波形図である。
【図５】無端ベルトの構成を示す模式図である。
【図６】感光体ドラム側より見た現像装置の構成を示す模式図である。
【符号の説明】
１ 感光体ドラム（像担持体）
４ 現像装置
４１ トナー搬送部材
４１ａ 基材
４１ｂ 進行波発生電極（電極）
１０１ 無端ベルト（ベルト部材）
Ｃ 無端ベルトの移動方向（ベルト部材の移動方向）
Ｇ 現像領域
Ｈ トナー搬送領域
Ｔ トナー
Ｖ 各進行波発生電極によるトナーの搬送方向
Ｘ 画像形成装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device that develops an electrostatic latent image formed on an image carrier with toner, and an image forming apparatus including the developing device, and more particularly, a mechanism that transports toner using a traveling wave electric field (electric field curtain). In this case, the present invention relates to a measure for preventing “white spots” of an electrostatic latent image due to a fixing toner on a belt member.
[0002]
[Prior art]
As a developing device applied to an image forming apparatus using an electrophotographic process such as a copying machine or a printer, a non-contact developing device that performs development without bringing a toner carrier into contact with an image carrier is currently attracting attention. Methods using the powder cloud method, jumping method and electric field curtain (traveling wave electric field) have been proposed.
[0003]
As a developing device using an electric field curtain, a power source that generates a plurality of types of alternating voltages having different phases from each other and a substrate disposed opposite to an image carrier that carries an electrostatic latent image on its surface A plurality of electrodes arranged at predetermined intervals, and a toner conveying member that conveys toner by a traveling wave electric field formed by applying an alternating voltage from the power source, and formed on the toner conveying member 2. Description of the Related Art Conventionally, a developing device that develops an electrostatic latent image by flying toner toward the image carrier by a traveling wave electric field is known (see, for example, Patent Document 1 and Patent Document 2).
[0004]
Further, as another developing device using an electric field curtain, a belt member that covers the surface of the toner conveying member and moves on the surface in a toner conveying direction at a low speed is formed by a traveling wave electric field formed on the toner conveying member. In some cases, an electrostatic latent image is developed by causing the toner conveyed on the belt member to fly toward an image carrier (see, for example, Patent Document 3).
[0005]
[Patent Document 1]
Japanese Patent Publication No. 5-31146
[Patent Document 2]
Japanese Patent Publication No. 5-31147
[Patent Document 3]
JP 2002-91160 A
[0006]
[Problems to be solved by the invention]
By the way, in the conventional developing device that transports toner by a traveling wave electric field on the belt member, when there is toner (fixed toner) that is not transported on the belt member for some reason, the fixed toner advances while the toner is being transported. As a result, the electrostatic latent image is not developed on the image carrier, and “white spots” occur.
[0007]
In that case, since the toner conveyance direction by the traveling wave electric field formed by each electrode and the moving direction of the belt member are the same direction, the fixed toner that is circulated and conveyed by the belt member feeding, and each electrode Since the toner transport direction coincides with the toner, the “white spot” occurs until the fixed toner disappears from the belt member, and good development cannot be performed.
[0008]
The present invention has been made in view of such points, and the object of the present invention is to prevent electrostatic white images from being “white-out” without being affected by the fixing toner on the belt member. An object of the present invention is to provide a developing device capable of developing and an image forming apparatus using the developing device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an electrode is disposed opposite to an image carrier that bears an electrostatic latent image on the surface thereof, and a plurality of electrodes arranged at predetermined intervals in the substrate. A toner conveying member that conveys toner by a traveling wave electric field formed by applying a plurality of types of alternating voltages having different phases, and a belt member that covers the surface of the toner conveying member and moves on the surface in a toner conveying direction at a low speed And a developing device that develops an electrostatic latent image by causing the toner conveyed on the belt member to fly toward the image carrier by a traveling wave electric field formed on the toner conveying member. . The toner transport direction by the plurality of electrodes is different from the moving direction of the belt member by a predetermined angle.
[0010]
Due to this specific matter, the toner transport direction by each electrode and the moving direction of the belt member are different from each other by a predetermined angle. Therefore, the fixed toner on the belt member looks laterally as viewed from the toner transport direction by each electrode. Therefore, the time for hindering the traveling direction of the toner is shortened, and “white spots” are reduced. For this reason, even if the fixed toner is generated on the belt member, it is possible to perform good development without affecting development.
[0011]
In particular, the toner transport direction by a plurality of electrodes is different from the belt member movement direction by a predetermined angle, and the electrodes are the same in at least a development area facing the image carrier in the toner transport area. When arranged at an angle, it is possible to carry out stable toner conveyance without changing the flying state of the toner at least in the development region.
[0012]
In addition, when an electrode on the most upstream side in the toner transport direction is disposed on the belt member downstream of the toner supply unit that supplies toner and in the development region or upstream of the development region, toner transport is not performed. The toner transport and toner supply are not performed at the same place on the belt member as in the case where the electrode on the most upstream side in the toner transport direction to be started is upstream of the toner supply unit. It is possible to prevent the toner layer from being disturbed. In addition, the toner transport is not performed in the portion where the fixed toner is generated on the belt member as in the case where the electrode on the most upstream side in the toner transport direction is on the downstream side of the development region, and the development with the toner is smoothly performed. Can be performed.
[0013]
In addition, when the toner transport direction by each electrode and the moving direction of the belt member are different from each other within an angle range of 3 ° to 20 °, fixed toner is generated on the belt member. However, it is possible to perform good development without affecting development due to “white spots”, and in addition to the difference in angle between the toner conveyance direction and the belt member movement direction by each electrode, An increase in size can be suppressed as much as possible.
[0014]
Further, when the above-described developing device is provided in the image forming apparatus, it is possible to provide an image forming apparatus capable of performing good development without affecting development by the fixing toner generated on the belt member. Become.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a diagram showing a configuration of an image forming apparatus including a developing device according to an embodiment of the present invention.
[0017]
In FIG. 1, a cylindrical photosensitive drum 1 as an image carrier is provided inside an image forming apparatus X. A charging member 2, an exposure member 3, a developing device 4, a transfer member 5, a cleaning member 6, and a charge removal member 7 are sequentially arranged around the photosensitive drum 1.
[0018]
Further, between the photosensitive drum 1 and the transfer member 5, a paper conveyance path for conveying paper (PPC paper or the like) P is disposed. A fixing device 8 including a pair of upper and lower fixing members 81 and 81 is disposed on the downstream side of the photosensitive drum 1 when viewed from the conveying direction of the sheet conveying path.
[0019]
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 developed (visualized) by the developing device 4. Then, the image is formed by being transferred onto the paper P.
[0020]
The photoconductive drum 1 has a photoconductive layer 12 formed on a conductive substrate 11 and is rotatable from the charging member 2 according to the arrangement order of the members 3 to 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 photosensitive drum 1 charged to a predetermined potential reaches the position of the exposure member 3 by the rotation of the photosensitive drum 1. The exposure member 3 is a writing unit, and writes an image on the surface of the photosensitive drum 1 that is charged by light such as laser light based on image information. As a result, an electrostatic latent image is formed on the photosensitive drum 1. The surface of the photosensitive drum 1 on which the electrostatic latent image is formed reaches the position of the developing device 4 by the rotation of the photosensitive drum 1.
[0021]
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 conveyed on the toner conveying member 41. The surface of the photosensitive drum 1 carrying the toner T reaches the position of the transfer member 5 by the rotation of the photosensitive drum 1.
[0022]
The transfer member 5 transfers the toner T 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 on the paper P by the fixing device 8.
[0023]
The surface of the photosensitive drum 1 after the toner image is transferred reaches the position of the cleaning member 6 by the rotation of the photosensitive drum 1. The cleaning member 6 removes toner T and paper dust remaining on the surface of the photosensitive drum 1. The surface of the photosensitive drum 1 cleaned by the cleaning member 6 reaches the position of the charge eliminating member 7 by the rotation of the photosensitive drum 1.
[0024]
The neutralizing member 7 removes the potential remaining on the surface of the photosensitive drum 1. One image formation is completed by the series of operations described above.
[0025]
As the photosensitive drum 1, for example, photoconductive materials such as amorphous silicon (a-Si), selenium (Se), and organic photo semiconductor (OPC) are formed on the outer peripheral surface of a conductive substrate (metal drum) 11 made of aluminum or the like. Although the structure by which the layer 12 is formed in a thin film form is mentioned, it is not specifically limited.
[0026]
Examples of the charging member 2 include a conductive wire such as a tungsten wire, a metal shield plate, a corona charger made of a grid plate, a charging roller, a charging brush, and the like, but is not particularly limited.
[0027]
Examples of the exposure member 3 include a semiconductor laser and a light emitting diode, but are not particularly limited.
[0028]
Examples of the transfer member 5 include a corona transfer device, a transfer roller, and a transfer brush, but are not particularly limited.
[0029]
Examples of the cleaning member 6 include a cleaning blade, but are not particularly limited.
[0030]
The neutralization member 7 includes a neutralization lamp, but is not particularly limited.
[0031]
Next, the developing device 4 will be described.
[0032]
As shown in FIG. 2, the developing device 4 includes a casing 40, a toner conveying member 41, a mixing paddle 42, a support member 43, a toner supply member 44, a toner collecting member 45, a toner layer thickness regulating member 46, and an endless belt member. The multi-phase AC power source 47 and the developing bias DC power source 48 are connected to the toner conveying member 41.
[0033]
The casing 40 accommodates the toner T therein, and supports members constituting the developing device 4 as necessary.
[0034]
The mixing paddle 42 is for mixing the toner T accommodated in the casing 40.
[0035]
The toner conveying member 41 has a belt shape that forms a substantially flat surface facing the developing region G of the photosensitive drum 1. In the present embodiment, the toner conveying member 41 has a substantially planar shape, but the shape of the toner conveying member 41 is not limited to this, and for example, a shape that forms a gently curved surface. It does not matter.
[0036]
The toner conveying member 41 is disposed so as to be slightly inclined with respect to the vertical direction of the developing device 4 and substantially parallel to the tangent line of the developing region G on the surface of the photosensitive drum 1. Further, a support member 43 that holds the toner conveying member 41 is provided on the surface opposite to the surface that conveys the toner T so that the belt-shaped toner conveying member 41 can maintain the above-described arrangement.
[0037]
A toner supply member 44 that supplies toner T conveyed on the surface of the toner conveyance member 41 is provided at a lower end portion of the toner conveyance member 41. A toner collecting member 45 for collecting the toner T on the surface of the toner conveying member 41 in the casing 40 is provided at the upper end of the toner conveying member 41. In the present embodiment, the toner collecting member 45 is configured to be in contact with the surface of the toner conveying member 41 so as to be rotatable. However, the present invention is not limited to this. It may be.
[0038]
The toner supply member 44 is for supplying the toner T accommodated in the casing 40 to the toner conveying member 41, and is provided in contact with the toner conveying member 41 with a linear pressure described later. The pressure contact force between the toner supply member 44 and the toner conveying member 41 is given by a spring or the like. The toner supply member 44 is in contact with a toner layer thickness regulating member 46 for regulating the thickness of the toner layer formed on the surface thereof.
[0039]
The material of the toner supply member 44 is not particularly limited, and examples thereof include solid rubber such as silicone, urethane, EPDM (ethylene-propylene-methylene copolymer), and foam rubber. Further, conductivity may be imparted by adding carbon black or an ionic conductive agent (voltage application is also possible). The positional relationship between the toner supply member 44 and the toner conveying member 41 may be controlled by adjusting the elastic modulus. Furthermore, the voltage applied to the toner supply member 44 may be set to an appropriate value, and a function for charging the toner T may be added to the toner supply member 44. Alternatively, for example, a thin plate-like blade (the same material as that of the toner supply member 44 can be used) may be provided before the toner supply member 44 to charge the toner T.
[0040]
The toner collecting member 45 is for collecting the toner T that does not contribute to the development of the electrostatic latent image on the photosensitive drum 1 and returning it to the casing 40. The material of the toner collecting member 45 is not particularly limited. The same supply member 44 can be used.
[0041]
The support member 43 is for holding the belt-shaped toner conveying member 41 facing the development region G of the photosensitive drum 1, and the configuration thereof is not particularly limited. For example, ABS (Acrylonitrile-Butadiene-Styrene) resin can be used.
[0042]
The toner conveying member 41 conveys the toner T by an electric field curtain action, and as shown in FIG. 3, a long traveling wave generating electrode for generating an electric field curtain action on a base material 41a made of an insulating layer. 41b is arranged such that a plurality of sets are successively arranged with four as one set. The surface side of the toner conveying member 41 is covered with a surface protective layer 41c.
[0043]
Then, by applying a multiphase alternating voltage from the multiphase AC power supply 47 to these traveling wave generating electrodes 41b... 41b, an electric field curtain is generated in a direction parallel to the surface of the toner conveying member 41. Thus, the toner T is conveyed to the developing region G by the electric field curtain action. Further, a bias voltage is applied to the traveling wave generating electrodes 41b.
[0044]
Specific examples of the toner conveying member 41 include, for example, a base material 41a: polyimide (thickness: 25 μm), traveling wave generating electrode 41b: copper (thickness: 12 μm), and surface protection layer 41c: polyimide (thickness: 12 μm). Can be mentioned.
[0045]
The traveling wave generating electrodes 41b are arranged in parallel with each other at intervals of about 50 dpi (dots per inch) to 300 dpi, that is, about 500 μm to 85 μm, and are minute electrodes having a width of about 40 μm to 250 μm. In this embodiment, four traveling wave generating electrodes 41b are made into one set, and a four-phase alternating voltage having a voltage waveform as shown in FIG. 4 is applied to each set of traveling wave generating electrodes 41b. However, the traveling wave electric field is formed on the traveling wave generating electrodes 41b... 41b. However, the present invention is not limited to this, and the three traveling wave generating electrodes 41b are used as one set to apply a three-phase alternating voltage. It doesn't matter.
[0046]
The voltage waveform may be a sine wave or a trapezoidal wave, and the voltage value range is preferably about 100 V to 3 kV. The frequency range is preferably 100 Hz to 5 kHz. However, these voltage values and frequencies may be set appropriately depending on the shape of the traveling wave generating electrode 41b, the transport speed of the toner T, the material used for the toner T, and the like, and are not particularly limited.
[0047]
The endless belt 101 is provided so as to cover the surface of the toner conveying member 41 (the surface facing the photosensitive drum 1) in the circumferential direction. The endless belt 101 is moved (rotated) at a predetermined peripheral speed in the toner T conveyance direction by a belt driving member 102 provided in the casing 40.
[0048]
As described above, the endless belt 101 moves in the toner transport direction (indicated by an arrow in FIG. 1) at a predetermined peripheral speed, so that the surface of the toner transport member 41 is constantly renewed. Is prevented from sticking.
[0049]
The driving speed of the endless belt 101 is preferably controlled to a level that is considered to be substantially stationary with respect to the toner T conveyance speed. For example, the driving speed of the endless belt 101 is 1/10 to 100 with respect to the toner T conveyance speed. It is set to about 1 / min. Note that the speed of the endless belt 101 may be, for example, a method in which two infrared sensors are provided and each detects the time when the toner T reaches or a method using a high-speed video camera (for example, IS & Ts NIP 15). : 1999 International Conference on Digital Printing Technologies p.262-265).
[0050]
A constant tension is applied to the endless belt 101 so as to be in close contact with the surface of the toner conveying member 41, and a traveling wave electric field (electric field curtain) formed on the surface by the traveling wave generating electrode 41b. Works uniformly.
[0051]
Materials for the endless belt 101 include organic insulating materials such as polyimide, PET (polyethylene terephthalate), polytetrafluoroethylene, polyfluorinated ethylene proprene, and PTFE (polytetrafluoroethylene), and rubbers such as silicon, isoprene, and butadiene. Materials can be mentioned. Further, the thickness of the endless belt 101 is 5 μm to 200 μm, preferably 10 μm to 100 μm, although it depends on the inter-electrode pitch λ (see FIG. 3) of the toner conveying member 41.
[0052]
As the belt driving member 102, a metal roller member such as SUS (stainless steel) or iron, or a member obtained by coating the surface with a member such as a rubber, a film, or a sponge using the same as a core metal is used.
[0053]
Further, as shown in FIG. 5, in this embodiment, in order to smoothly rotate the endless belt 101, a drive assisting member 103 is provided so as to come into contact with the belt driving member 102 via the endless belt 101. It has been. The endless belt 101 is sandwiched between the belt drive member 102 and the drive assisting member 103, has high contact with the belt drive member 102, and obtains a high driving force.
[0054]
Examples of the driving assisting member 103 include, like the belt driving member 102, a metal roller member such as SUS or iron, or a member in which a member such as rubber, a film, or a sponge is coated on the surface thereof. it can. Further, the shape of the drive assisting member 103 may be not only a roller shape but also a plate shape or a square shape. Further, the drive assisting member 103 may be provided with a pressurizing means (not shown) for making pressure contact with the belt drive member 102. As the pressurizing means, for example, a plate spring, a coil spring or the like that can apply a pressing force can be exemplified.
[0055]
Examples of the rotation mechanism of the drive assisting member 103 include a driven rotation mechanism by contact with the endless belt 101, a connection drive mechanism that is connected to a drive source of the belt drive member 102 by a gear or a pulley and a belt. Although not shown, the drive assisting member 103 may be provided with another drive source.
[0056]
Further, by electrically grounding the drive assisting member 103, the potential charged on the surface of the endless belt 101 can be eliminated.
[0057]
Further, in this embodiment, a cleaning blade 104 that abuts the belt driving member 102 via the endless belt 101 is provided as a cleaning member for removing the toner T adhering to the endless belt 101. The cleaning blade 104 is fixed to a part of the casing 40. Examples of the material of the cleaning blade 104 include SUS, nickel-coated iron, urethane, or silicon rubber.
[0058]
The cleaning blade 104 scrapes off the toner T remaining on the endless belt 101, cleans the surface of the endless belt 101, and returns the toner T to the toner accumulation portion 40a of the casing 40. In the structure of FIG. 2, the endless belt 101 side is separated from the toner accumulation unit 40a side so that the toner T does not adhere to the endless belt 101 existing between the cleaning blade 104 and the toner supply member 44. The partition member 105 is provided so that the endless belt 101 can be cleaned more effectively.
[0059]
As a feature of the present invention, as shown in FIG. 6, the transport direction V of the toner T by each traveling wave generating electrode 41b is a predetermined angle θ (for example, θ = 5) with respect to the moving direction C of the endless belt 101. °) It is configured to tilt. Each of the traveling wave generating electrodes 41b has the same angle (with respect to an orthogonal line K orthogonal to the moving direction C of the endless belt 101) in all the areas (toner conveyance areas H and H and development area G) where the toner T is conveyed. In a state inclined at a predetermined angle θ). The traveling wave generating electrode 41b on the most upstream side in the toner transport direction is downstream of the contact portion 44X of the toner supply member 44 with respect to the endless belt 101 (shown by a one-dot chain line in FIG. 6) and in the developing region G (in FIG. 6). (Indicated by a two-dot chain line).
[0060]
Here, the grounds for inclining the conveying direction V of the toner T by each traveling wave generating electrode 41b with respect to the moving direction C of the endless belt 101 by a predetermined angle θ (for example, θ = 5 °) will be described.
[0061]
As shown in Table 1 below, when the traveling direction V of the toner T by each traveling wave generating electrode 41b is inclined by 1 ° and 1.5 ° with respect to the moving direction C of the endless belt 101, some sort of motion is generated on the endless belt. The fixed toner that is not transported due to the cause prevents the toner being transported from progressing, and the electrostatic latent image on the photosensitive drum is not developed, and “white spot” is generated.
[0062]
Further, when the conveying direction V of the toner T by each traveling wave generating electrode 41b is inclined by 2 ° with respect to the moving direction C of the endless belt 101, the fixed toner on the endless belt 101 hinders the progress of the toner and “white Although “missing” does not occur, a phenomenon occurs in which the density becomes thin over a wide range, and it can be seen that the determination is Δ.
[0063]
Further, when the conveying direction V of the toner T by each traveling wave generating electrode 41b is inclined by 2.5 ° with respect to the moving direction C of the endless belt 101, the fixed toner on the endless belt 101 hinders the progress of the toner. Although “white spots” do not occur, a phenomenon occurs in which the density decreases in a narrow range, and it can be seen that the determination is Δ.
[0064]
When the traveling direction V of the toner T by each traveling wave generating electrode 41b is inclined by 3 ° with respect to the moving direction C of the endless belt 101, the fixed toner on the endless belt 101 is prevented from obstructing the progress of the toner. Therefore, it can be seen that good development can be performed, and that the determination is good.
[0065]
From the above results, it can be seen that the conveying direction V of the toner T by each traveling wave generating electrode 41b may be inclined by 3 ° or more with respect to the moving direction C of the endless belt 101. In the present embodiment, The traveling direction V of the toner T by each traveling wave generating electrode 41b is inclined by 5 ° with respect to the moving direction C of the endless belt 101.
[0066]
[Table 1]

Therefore, in the above embodiment, the toner T transport direction V by each traveling wave generating electrode 41b is inclined by 5 ° with respect to the moving direction C of the endless belt 101. When viewed from the conveying direction V of the toner T by the generation electrode 41b, it apparently shifts to the side, so that the time for hindering the traveling direction of the toner T is shortened, and “white spots” are reduced. Therefore, even if the fixed toner is generated on the endless belt 101, good development can be performed without affecting the development.
[0067]
In addition, each traveling wave generating electrode 41b has the same angle (the orthogonal line K orthogonal to the moving direction C of the endless belt 101) in all the areas (toner conveyance areas H and H and the development area G) where the toner T is conveyed. The toner T can be stably transported without changing the flying state of the toner T in the toner transport regions H and H and the development region G.
[0068]
Since the traveling wave generating electrode 41b on the most upstream side in the toner conveying direction is disposed downstream of the contact portion 44X of the toner supply member 44 with respect to the endless belt 101 and upstream of the developing region G, the toner T In the same place on the endless belt as in the case where the traveling wave generating electrode 41b on the most upstream side in the toner conveyance direction is upstream of the contact portion 44X with the toner supply member 44, toner conveyance and toner supply are performed. The toner layer to be controlled at the time of toner supply can be prevented from being disturbed. In addition, the traveling wave generating electrode 41b on the most upstream side in the toner transport direction is not downstream of the development region G, so that the toner transport is not performed in the portion where the fixed toner is generated on the endless belt. Development with toner T can be performed smoothly.
[0069]
Further, since each traveling wave generating electrode 41b is inclined by 5 ° with respect to the orthogonal line K orthogonal to the moving direction C of the endless belt 101, when the fixed toner is generated on the endless belt 101, Developing device 4 based on the difference in angle between the transport direction V of toner T by each traveling wave generating electrode 41b and the moving direction C of endless belt 101 while performing good development without affecting development due to white spots. Can be effectively suppressed.
[0070]
Furthermore, by providing the above-described developing device 4 in the image forming apparatus X, an image forming apparatus X that can perform good development without affecting the development by the fixed toner generated on the endless belt 101 is provided. Can do.
[0071]
In addition, this invention is not limited to the said embodiment, The other various modifications are included. For example, in the above embodiment, the transport direction V of the toner T by each traveling wave generating electrode 41b is inclined by 5 ° with respect to the moving direction C of the endless belt 101, but the moving direction of the endless belt is the toner by each traveling wave generating electrode. In this case, similar actions and effects can be obtained.
[0072]
Further, the traveling direction of the toner by each traveling wave generating electrode and the moving direction of the endless belt may be inclined as long as they are different from each other within an angle range of 3 ° to 20 °. Even if the fixed toner is generated on the endless belt, the toner is transported by the traveling wave generating electrodes and the moving direction of the belt member while performing good development without affecting the development by “white spot”. Therefore, an increase in the size of the developing device due to the difference in angle between the two can be suppressed as much as possible. When the traveling direction of the toner by each traveling wave generating electrode and the moving direction of the endless belt are different from each other by 20 ° or more, there is almost no change in the “white spot” reduction effect (“white spot” reduction effect and The relationship with the angle difference is presumed to be related to the size of the fixed toner.) Increasing the angle of inclination increases the length of the toner conveying member in the belt feeding direction, which reduces the size of recent developing devices. It is not preferable to increase the tilt angle because the flow is reversed.
[0073]
【The invention's effect】
As described above, the toner conveyance direction of each electrode that conveys toner by a traveling wave electric field on the surface of the toner conveyance member, and the movement direction of the belt member that moves at a low speed in the toner conveyance direction on the surface of the toner conveyance member, By making them differ from each other by a predetermined angle, the fixed toner on the belt member is apparently shifted laterally when viewed from the direction of toner conveyance by each electrode, shortening the time that obstructs the toner traveling direction, and reducing “white spots”. Therefore, it is possible to perform good development without affecting development regardless of the presence of the fixed toner on the belt member.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a schematic configuration of an image forming apparatus using an electrophotographic system to which a developing device according to an embodiment of the present invention is applied.
FIG. 2 is a schematic diagram illustrating a configuration of a developing device.
FIG. 3 is a schematic diagram illustrating a configuration of a toner conveying member.
FIG. 4 is a waveform diagram illustrating a voltage waveform applied to a toner conveying member.
FIG. 5 is a schematic diagram showing a configuration of an endless belt.
FIG. 6 is a schematic diagram illustrating a configuration of a developing device viewed from the photosensitive drum side.
[Explanation of symbols]
1 Photosensitive drum (image carrier)
4 Development device
41 Toner conveying member
41a base material
41b Traveling wave generating electrode (electrode)
101 Endless belt (belt member)
C Moving direction of endless belt (moving direction of belt member)
G Development area
H Toner transport area
T Toner
V Toner transport direction by each traveling wave generating electrode
X image forming apparatus

Claims (5)

By applying a plurality of types of alternating voltages with different phases to electrodes arranged on a surface of an electrostatic latent image opposite to an image carrier that is arranged at predetermined intervals in the substrate. A toner conveying member that conveys toner by a traveling wave electric field that is formed, and a belt member that covers the surface of the toner conveying member and moves on the surface in the toner conveying direction at a low speed, formed on the toner conveying member In the developing device in which the toner conveyed on the belt member by the traveling wave electric field is caused to fly toward the image carrier to develop the electrostatic latent image.
2. A developing device according to claim 1, wherein a direction in which toner is conveyed by the plurality of electrodes and a direction in which the belt member moves are different from each other by a predetermined angle. In the developing device according to claim 1,
The direction of toner conveyance by the plurality of electrodes is different from the direction of movement of the belt member at a predetermined angle,
Each of the electrodes is arranged at the same angle in at least a developing area facing the image carrier in the toner conveying area. In the developing device according to claim 2,
The developing device characterized in that the most upstream electrode in the toner transport direction is disposed downstream of a toner supply unit that supplies toner onto the belt member and in the developing region or upstream of the developing region. In the developing device according to any one of claims 1 to 3,
2. A developing device according to claim 1, wherein the toner conveying direction by each electrode and the moving direction of the belt member are different from each other within an angle range of 3 ° to 20 °. An image forming apparatus comprising the developing device according to any one of claims 1 to 4.

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