JP4980639B2 - Developing device, process unit and image forming apparatus using the same - Google Patents

Developing device, process unit and image forming apparatus using the same Download PDF

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JP4980639B2
JP4980639B2 JP2006096712A JP2006096712A JP4980639B2 JP 4980639 B2 JP4980639 B2 JP 4980639B2 JP 2006096712 A JP2006096712 A JP 2006096712A JP 2006096712 A JP2006096712 A JP 2006096712A JP 4980639 B2 JP4980639 B2 JP 4980639B2
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screw member
developer
developing device
supply screw
latent image
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JP2007271863A (en
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浩 細川
弘恭 長島
延雄 桑原
浩孝 八田
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Ricoh Co Ltd
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Ricoh Co Ltd
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本発明は、現像剤担持体に担持した現像剤によって潜像担持体上の潜像を現像する現像装置、並びにこれを用いるプロセスユニットに及び画像形成装置に係り、詳しくは、現像剤を搬送しながら現像剤担持体に供給する供給スクリュウ部材の改良に関するものである。   The present invention relates to a developing device that develops a latent image on a latent image carrier with a developer carried on the developer carrier, a process unit using the same, and an image forming apparatus. Specifically, the developer is conveyed. The present invention relates to an improvement of a supply screw member supplied to the developer carrying member.

従来、この種の現像装置として、特許文献１に記載のものが知られている。この現像装置は、現像剤担持体たる回転可能な現像ローラと、これに平行な姿勢をとるように配設された供給スクリュウ部材とを備えている。供給スクリュウ部材は、回転可能な軸部と、これの周面に螺旋状に突設せしめられた羽根部とを有しており、駆動手段によって回転駆動せしめられることで、現像剤を回転軸線方向に搬送する。現像ローラは、このようにして搬送される現像剤を自らの回転駆動に伴って供給スクリュウ部材の周囲から汲み上げて表面に担持した後、潜像担持体たる感光体に対向する現像領域に搬送して感光体上の潜像を現像する。   Conventionally, as this type of developing device, the one described in Patent Document 1 is known. The developing device includes a rotatable developing roller as a developer carrying member, and a supply screw member arranged to take a posture parallel to the developing roller. The supply screw member has a rotatable shaft portion and a blade portion projecting spirally on the peripheral surface thereof, and is driven to rotate by a driving means, whereby the developer is rotated in the direction of the rotation axis. Transport to. The developing roller draws up the developer conveyed in this way from the periphery of the supply screw member as it rotates and carries it on the surface, and then conveys it to the developing region facing the photosensitive member as the latent image carrier. To develop the latent image on the photosensitive member.

特開２００４−０７７５５４号公報JP 2004-077554 A

かかる構成の現像装置においては、現像ローラ等の現像剤担持体に対して十分量の現像剤を汲み上げさせるように、供給スクリュウ部材やその周囲に比較的多量の現像剤を充填するのが一般的であった。そして、このような充填により、現像剤に比較的高い圧力をかけて現像剤の劣化を早めてしまったり、駆動モータの駆動トルクを高くしてしまったりするという不具合があった。   In a developing device having such a configuration, a relatively large amount of developer is generally filled in the supply screw member and its surroundings so that a sufficient amount of developer is pumped up to a developer carrier such as a developing roller. Met. Such filling causes a problem that a relatively high pressure is applied to the developer to accelerate the deterioration of the developer, or the drive torque of the drive motor is increased.

そこで、本発明者らは、供給スクリュウ部材やその周囲に対する現像剤充填量を従来よりも少なくした条件下で画像を形成する実験を行った。すると、供給スクリュウ部材の駆動源のトルクを低減しつつ、現像剤の劣化を抑えることができた。   Therefore, the inventors conducted an experiment to form an image under the condition that the developer filling amount with respect to the supply screw member and its surroundings is smaller than the conventional amount. Then, it was possible to suppress the deterioration of the developer while reducing the torque of the drive source of the supply screw member.

ところが、かかる構成では、現像剤担持体の回転軸線方向における中央部で周期的な現像濃度ムラを引き起こし易くなるという新たな問題が発生してしまった。そこで、このような現像濃度ムラを引き起こす原因について鋭意研究を行ったところ、次のようなことがわかってきた。即ち、軸線方向の両端部をそれぞれ軸受けによって回転自在に支持される供給スクリュウ部材は、その回転に伴って軸線方向の中央部を微妙に撓ませる。供給スクリュウ部材の周囲に比較的多量の現像剤を充填していた従来においては、このような撓みが生じても、供給スクリュウ部材の中央部と現像剤担持体との間の現像剤がその撓みに追従した挙動をとることは殆どなかった。しかし、供給スクリュウ部材やその周囲に対する現像剤充填量を少なくした上述の実験では、供給スクリュウ部材の中央部と現像剤担持体との間にそれほど多くの現像剤を存在させていない。このため、供給スクリュウ部材の中央部が撓むと、中央部と現像剤担持体との間の現像剤がその撓みに追従して現像剤担持体に対してより近づいたり、現像剤担持体から遠ざかったりする。そして、現像剤が現像剤担持体から遠ざかった際に、現像剤担持体の現像剤の汲み上げ量が不足し易くなる。このような汲み上げ量の不足が現像剤担持体の回転に伴って周期的に起こることから、現像剤担持体の軸線方向における中央部で周期的な濃度ムラを引き起こしていることがわかった。   However, with such a configuration, a new problem has arisen that it becomes easy to cause periodic development density unevenness at the central portion in the rotation axis direction of the developer carrier. Then, as a result of earnest research on the cause of such development density unevenness, the following has been found. That is, the supply screw member, which is rotatably supported by the bearings at both ends in the axial direction, slightly deflects the central portion in the axial direction along with the rotation. In the conventional case where a relatively large amount of developer is filled around the supply screw member, the developer between the central portion of the supply screw member and the developer carrying member is bent even when such a bend occurs. There was almost no behavior that followed. However, in the above-described experiment in which the developer filling amount with respect to the supply screw member and its surroundings is reduced, not much developer is present between the central portion of the supply screw member and the developer carrier. For this reason, when the central portion of the supply screw member bends, the developer between the central portion and the developer carrier follows the deflection and approaches the developer carrier or moves away from the developer carrier. Or When the developer moves away from the developer carrying member, the developer pumping amount of the developer carrying member tends to be insufficient. Such a shortage of the pumping amount occurs periodically with the rotation of the developer carrying member, and thus it has been found that periodic density unevenness is caused at the central portion in the axial direction of the developer carrying member.

本発明は、以上の背景に鑑みなされたものであり、その目的とするところは、供給スクリュウ部材やその周囲に対する現像剤充填量を従来よりも少なくすることに起因する周期的な現像濃度ムラを抑えることができる現像装置等を提供することである。   The present invention has been made in view of the above background, and the object of the present invention is to prevent periodic development density unevenness caused by reducing the amount of developer filling the supply screw member and its surroundings more than before. It is to provide a developing device or the like that can be suppressed.

上記目的を達成するために、請求項１の発明は、無端移動する表面に現像剤を担持する現像剤担持体と、該現像剤担持体の表面の無端移動方向と直交する方向に延在するように配設され、自らの回転に伴って現像剤を該方向に搬送しながら該現像剤担持体の表面に供給する供給スクリュウ部材とを備えるとともに、回転可能な軸部と、これの周面に螺旋状に突設せしめられた羽根部とを該供給スクリュウ部材に有し、該現像剤担持体に担持した現像剤によって潜像担持体上の潜像を現像する現像装置において、上記供給スクリュウ部材として、上記搬送されている現像剤が上記現像剤担持体に受け渡される領域に存在する上記軸部の軸線方向における中央部の径を、両端部よりも大きくし、且つ該中央部と該両端部とで上記羽根部の外径を同じにしたものを用いたことを特徴とするものである。
また、請求項２の発明は、請求項１の現像装置において、上記供給スクリュウ部材として、上記軸部の径を両端部から中央部に向けて段差なく徐々に大きくしたものを用いたことを特徴とするものである。
また、請求項３の発明は、請求項１又は２の現像装置において、回転可能な軸部と、これの周面に螺旋状に突設せしめられた羽根部とを有するスクリュウ部材であって、且つ自らの回転に伴って現像剤を回転軸線方向に搬送しながら上記供給スクリュウ部材の軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すスクリュウ部材である搬送スクリュウ部材を設けるとともに、該供給スクリュウ部材の軸線方向における現像剤搬送方向下流側の端部箇所まで搬送された現像剤を、該搬送スクリュウ部材の軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すようにし、該供給スクリュウ部材による単位時間あたりの現像剤搬送量を該搬送スクリュウ部材による単位時間あたりの現像剤搬送量よりも少なくしたことを特徴とするものである。
また、請求項４の発明は、請求項３の現像装置において、上記供給スクリュウ部材として、上記搬送スクリュウ部材よりも上記羽根部の外径を大きくしたものを用いたことを特徴とするものである。
また、請求項５の発明は、請求項３又は４の現像装置において、上記供給スクリュウ部材として、１回転あたりにおける現像剤搬送量を上記搬送スクリュウ部材の１回転あたりにおける現像剤搬送量よりも少なくしたものを用いたことを特徴とするものである。
また、請求項６の発明は、請求項５の現像装置において、上記供給スクリュウ部材として、上記羽根部の側面の面積を上記搬送スクリュウ部材における該面積よりも小さくしたものを用いたことを特徴とするものである。
また、請求項７の発明は、請求項６の現像装置において、上記供給スクリュウ部材として、上記搬送スクリュウ部材よりも上記羽根部の外径を大きくし、且つ上記軸部における上記中央部及び両端部の径を何れも該搬送スクリュウ部材の軸部の径よりも大きくしたものを用いたことを特徴とするものである。
また、請求項８の発明は、請求項６の現像装置において、上記供給スクリュウ部材として、上記羽根部に切り欠きを設けたものを用いたことを特徴とするものである。
また、請求項９の発明は、請求項５の現像装置において、上記供給スクリュウ部材として、現像剤を保持可能な螺旋状の空間の容積を上記搬送スクリュウ部材における該容積よりも小さくしたものを用いたことを特徴とするものである。
また、請求項１０の発明は、請求項９の現像装置において、上記供給スクリュウ部材として、上記羽根部の厚みを上記搬送スクリュウ部材における該厚みよりも大きくしたものを用いたことを特徴とするものである。
また、請求項１１の発明は、請求項９又は１０の現像装置において、上記供給スクリュウ部材として、上記羽根部の条数を上記搬送スクリュウ部材における該条数よりも多くしたものを用いたことを特徴とするものである。
また、請求項１２の発明は、請求項５の現像装置において、上記供給スクリュウ部材として、上記羽根部の軸線方向における配設ピッチを上記搬送スクリュウ部材における該配設ピッチよりも小さくしたものを用いたことを特徴とするものである。
また、請求項１３の発明は、請求項５の現像装置において、上記スクリュウ部材として、現像剤の螺旋方向への移動を阻害する移動阻害部材を上記軸部又は羽根部に設けたものを用いたことを特徴とするものである。
また、請求項１４の発明は、潜像を担持する潜像担持体と、該潜像担持体に担持される潜像を現像する現像装置とを用いて画像を形成する画像形成装置に搭載され、少なくとも該潜像担持体及び現像装置を１つのユニットとして共通の保持体で保持しながら画像形成装置本体に対して着脱されるプロセスユニットにおいて、上記現像装置として、請求項１乃至１３の何れかの現像装置を用いたことを特徴とするものである。
また、請求項１５の発明は、潜像担持体及びこれに担持される潜像を現像する現像装置を有するプロセスユニットを用いて画像を形成する画像形成装置において、上記プロセスユニットとして、請求項１４のプロセスユニットを用いたことを特徴とするものである。
また、請求項１６の発明は、請求項１５の画像形成装置において、上記プロセスユニットを複数設けるとともに、各プロセスユニットの潜像担持体上で現像された可視像を転写体に重ね合わせて転写する転写手段を設けたことを特徴とするものである。
また、請求項１７の発明は、潜像を担持する潜像担持体と、該潜像担持体に担持される潜像を現像する現像装置とを用いて画像を形成する画像形成装置において、上記現像装置として、請求項１乃至１３の何れかの現像装置を用いたことを特徴とするものである。 In order to achieve the above object, the invention of claim 1 is directed to a developer carrying member carrying a developer on an endlessly moving surface and a direction orthogonal to the endless moving direction of the surface of the developer carrying member. A supply screw member that supplies the developer to the surface of the developer carrier while conveying the developer in the direction along with its rotation, and a rotatable shaft portion, and a peripheral surface thereof In the developing device for developing the latent image on the latent image carrier with the developer carried on the developer carrier, the blade provided in a spirally projecting manner on the supply screw member, as members, the diameter of the central portion in the axial direction of the shaft portion which the developer being the transfer is present in the region to be passed to the developer carrying member, and larger than both end portions, and the central portion and said The outer diameter of the blade is the same at both ends. It is characterized in that was used to.
According to a second aspect of the present invention, in the developing device according to the first aspect, the supply screw member is formed by gradually increasing the diameter of the shaft portion from both end portions toward the central portion without any step. It is what.
The invention of claim 3 is a screw member according to claim 1 or 2, wherein the screw member has a rotatable shaft portion and a blade portion spirally provided on the peripheral surface of the shaft portion. And a conveying screw member that is a screw member that delivers the developer to the upstream end portion in the developer conveying direction in the axial direction of the supply screw member while conveying the developer in the rotational axis direction along with its rotation, The developer conveyed to the downstream end portion in the developer conveying direction in the axial direction of the supply screw member is transferred to the upstream end portion in the developer conveying direction in the axial direction of the conveying screw member, and The developer transport amount per unit time by the supply screw member is smaller than the developer transport amount per unit time by the transport screw member. Than is.
According to a fourth aspect of the present invention, in the developing device according to the third aspect, the supply screw member is one having an outer diameter of the blade portion larger than that of the conveying screw member. .
According to a fifth aspect of the present invention, in the developing device according to the third or fourth aspect, as the supply screw member, a developer conveyance amount per rotation is smaller than a developer conveyance amount per rotation of the conveyance screw member. It is characterized by using what was done.
According to a sixth aspect of the present invention, in the developing device according to the fifth aspect of the present invention, the supply screw member has a side surface area smaller than that of the conveying screw member. To do.
Further, the invention of claim 7 is the developing device according to claim 6, wherein the supply screw member has an outer diameter larger than that of the conveying screw member, and the central portion and both end portions of the shaft portion. The diameter of each is larger than the diameter of the shaft portion of the conveying screw member.
According to an eighth aspect of the present invention, in the developing device of the sixth aspect, the supply screw member having a notch in the blade portion is used.
The invention according to claim 9 is the developing device according to claim 5, wherein the supply screw member has a helical space capable of holding developer smaller than the volume of the conveying screw member. It is characterized by the fact that
According to a tenth aspect of the present invention, in the developing device according to the ninth aspect, the supply screw member having a thickness of the blade portion larger than the thickness of the conveying screw member is used. It is.
The invention according to claim 11 is the developing device according to claim 9 or 10, wherein the supply screw member has a larger number of the blade portions than the number of the supply screw members. It is a feature.
According to a twelfth aspect of the present invention, in the developing device according to the fifth aspect, the supply screw member having an arrangement pitch in the axial direction of the blade portion smaller than the arrangement pitch in the conveying screw member is used. It is characterized by the fact that
The invention according to claim 13 is the developing device according to claim 5, wherein the screw member is provided with a movement inhibiting member that inhibits the movement of the developer in the spiral direction at the shaft portion or the blade portion. It is characterized by this.
The invention according to claim 14 is mounted in an image forming apparatus that forms an image using a latent image carrier that carries a latent image and a developing device that develops the latent image carried on the latent image carrier. 14. The process unit according to claim 1, wherein at least the latent image carrier and the developing device are attached to and detached from the image forming apparatus main body while being held by a common holder as a unit. The developing device is used.
According to a fifteenth aspect of the present invention, there is provided an image forming apparatus for forming an image using a process unit having a latent image carrier and a developing device for developing the latent image carried on the latent image carrier. The process unit is used.
According to a sixteenth aspect of the present invention, in the image forming apparatus according to the fifteenth aspect, a plurality of the process units are provided, and a visible image developed on the latent image carrier of each process unit is superimposed and transferred onto the transfer body. It is characterized in that a transfer means is provided.
According to a seventeenth aspect of the present invention, there is provided an image forming apparatus for forming an image using a latent image carrier that carries a latent image and a developing device that develops the latent image carried on the latent image carrier. The developing device according to any one of claims 1 to 13 is used as the developing device.

これらの発明では、供給スクリュウ部材の軸部の軸線方向における中央部の径が両端部よりも大きくなっていることにより、供給スクリュウ部材の中央部における螺旋状の空間の容積が両端部よりも小さくなる。このため、中央部では、両端部に比べて、螺旋状の空間内に収まりきれずにスクリュウの外側に押し出される現像剤の量が多くなる。そして、供給スクリュウ部材と現像剤担持体との間に介在する現像剤の量が両端部に比べて多くなる。これにより、供給スクリュウ部材の中央部が回転に伴って撓んでも、現像剤担持体の中央部に対して十分量の現像剤を汲み上げさせて、周期的な現像濃度ムラを抑えることができる。よって、供給スクリュウ部材やその周囲に対する現像剤充填量を従来よりも少なくすることに起因する周期的な現像濃度ムラを抑えることができる。   In these inventions, since the diameter of the central portion in the axial direction of the shaft portion of the supply screw member is larger than both end portions, the volume of the spiral space in the central portion of the supply screw member is smaller than both end portions. Become. For this reason, in the central portion, the amount of the developer that is pushed out to the outside of the screw without being contained in the spiral space is larger than in the both end portions. Then, the amount of the developer interposed between the supply screw member and the developer carrier is larger than that at both ends. As a result, even if the central portion of the supply screw member bends with rotation, a sufficient amount of developer can be pumped up to the central portion of the developer carrying member, and periodic development density unevenness can be suppressed. Therefore, it is possible to suppress periodic development density unevenness caused by reducing the developer filling amount with respect to the supply screw member and its surroundings as compared with the conventional case.

以下、本発明を適用した画像形成装置として、電子写真方式のプリンタ（以下、単にプリンタという）の一実施形態について説明する。
まず、本プリンタの基本的な構成について説明する。図１は、本プリンタを示す概略構成図である。同図において、プリンタ１００は、イエロー、マゼンタ、シアン、ブラック（以下、Ｙ、Ｍ、Ｃ、Ｋと記す）のトナー像を生成するための４つのプロセスカートリッジ６Ｙ，Ｍ，Ｃ，Ｋを備えている。これらは、画像形成物質として、互いに異なる色のＹ，Ｍ，Ｃ，Ｋトナーを用いるが、それ以外は同様の構成になっており、寿命到達時に交換される。Ｙトナー像を生成するためのプロセスカートリッジ６Ｙを例にすると、図２に示すようにドラム状の像担持体としての感光体１Ｙ、ドラムクリーニング装置２Ｙ、除電装置（不図示）、帯電装置４Ｙ、現像装置５Ｙ等を備えている。このプロセスカートリッジ６Ｙは、プリンタ１００本体に脱着可能であり、一度に消耗部品を交換できるようになっている。 Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described.
First, the basic configuration of the printer will be described. FIG. 1 is a schematic configuration diagram showing the printer. In FIG. 1, the printer 100 includes four process cartridges 6Y, 6M, 6C, and 6K for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). Yes. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached. Taking a process cartridge 6Y for generating a Y toner image as an example, as shown in FIG. 2, a photosensitive member 1Y as a drum-shaped image carrier, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device 4Y, A developing device 5Y and the like are provided. The process cartridge 6Y can be attached to and detached from the main body of the printer 100 so that consumable parts can be replaced at a time.

帯電装置４Ｙは、図示しない駆動手段によって図中時計回りに回転せしめられる感光体１Ｙの表面を一様に帯電せしめる。一様に帯電せしめられた感光体１Ｙの表面は、レーザ光Ｌによって露光走査されてＹ用の静電潜像を担持する。このＹの静電潜像は、Ｙトナーを用いる現像装置５ＹによってＹトナー像に現像される。そして、中間転写ベルト８上に中間転写される。ドラムクリーニング装置２Ｙは、中間転写工程を経た後の感光体１Ｙ表面に残留したトナーを除去する。また除電装置は、クリーニング後の感光体１Ｙの残留電荷を除電する。この除電により、感光体１Ｙの表面が初期化されて次の画像形成に備えられる。他のプロセスカートリッジ６Ｍ、Ｃ、Ｋにおいても、同様にして感光体１Ｍ、Ｃ、Ｋ上にＭ、Ｃ、Ｋトナー像が形成され、中間転写ベルト８上に中間転写される。   The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that is rotated clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry an electrostatic latent image for Y. The Y electrostatic latent image is developed into a Y toner image by the developing device 5Y using Y toner. Then, intermediate transfer is performed on the intermediate transfer belt 8. The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process. The static eliminator neutralizes residual charges on the photoreceptor 1Y after cleaning. By this charge removal, the surface of the photoreceptor 1Y is initialized and prepared for the next image formation. In the other process cartridges 6M, C, and K, M, C, and K toner images are similarly formed on the photoreceptors 1M, C, and K, and are intermediately transferred onto the intermediate transfer belt 8.

先に示した図１においてプロセスカートリッジ６Ｙ、Ｍ、Ｃ、Ｋの図中下方には露光装置７が配設されている。潜像形成手段たる露光装置７は、画像情報に基づいて発したレーザ光Ｌを、プロセスカートリッジ６Ｙ、Ｍ、Ｃ、Ｋにおけるそれぞれの感光体に照射して露光する。この露光により、感光体１Ｙ，Ｍ，Ｃ，Ｋ上にＹ，Ｍ，Ｃ，Ｋ用の静電潜像が形成される。なお露光装置７は、光源から発したレーザ光Ｌを、モータによって回転駆動したポリゴンミラーで走査しながら、複数の光学レンズやミラーを介して感光体に照射するものである。   In FIG. 1 shown above, an exposure device 7 is arranged below the process cartridges 6Y, 6M, 6C, and 6K in the drawing. The exposure device 7 serving as a latent image forming unit irradiates each of the photoconductors in the process cartridges 6Y, 6M, 6C, and 6K with a laser beam L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photosensitive member through a plurality of optical lenses and mirrors while scanning a laser beam L emitted from a light source with a polygon mirror rotated by a motor.

露光装置７の図中下側には、紙収容カセット２６、これらに組み込まれた給紙ローラ２７、レジストローラ対２８など有する給紙手段が配設されている。紙収容カセット２６は、記録体たる転写紙Ｐが複数枚重ねて収納されており、それぞれの一番上の転写紙Ｐには給紙ローラ２７が当接している。給紙ローラ２７が図示しない駆動手段によって図中反時計回りに回転せしめられると、一番上の転写紙Ｐがレジストローラ対２８のローラ間に向けて給紙される。レジストローラ対２８は、転写紙Ｐを挟み込むべく両ローラを回転駆動するが、挟み込んですぐに回転を一旦停止させる。そして、転写紙Ｐを適切なタイミングで後述の２次転写ニップに向けて送り出す。   On the lower side of the exposure apparatus 7 in the figure, paper supply means including a paper storage cassette 26, a paper supply roller 27 incorporated therein, a registration roller pair 28, and the like are disposed. The paper storage cassette 26 stores a plurality of transfer papers P as recording bodies, and a paper feed roller 27 is in contact with each uppermost transfer paper P. When the paper feeding roller 27 is rotated counterclockwise in the drawing by a driving means (not shown), the uppermost transfer paper P is fed toward the rollers of the registration roller pair 28. The registration roller pair 28 rotationally drives both rollers to sandwich the transfer paper P, but temporarily stops rotating immediately after sandwiching. Then, the transfer paper P is sent out toward a later-described secondary transfer nip at an appropriate timing.

プロセスカートリッジ６Ｙ，Ｍ，Ｃ，Ｋの図中上方には、中間転写体たる中間転写ベルト８を張架しながら無端移動せしめる中間転写ユニット１５が配設されている。この中間転写ユニット１５は、中間転写ベルト８の他、４つの１次転写バイアスローラ９Ｙ，Ｍ，Ｃ，Ｋ、クリーニング装置１０などを備えている。また２次転写バックアップローラ１２、クリーニングバックアップローラ１３、テンションローラ１４なども備えている。   Above the process cartridges 6Y, 6M, 6C, and 6K, an intermediate transfer unit 15 that moves the intermediate transfer belt 8 that is an intermediate transfer member endlessly while stretching is disposed. The intermediate transfer unit 15 includes, in addition to the intermediate transfer belt 8, four primary transfer bias rollers 9Y, M, C, and K, a cleaning device 10, and the like. A secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14 and the like are also provided.

中間転写ベルト８は、これら３つのローラに張架されながら、少なくとも何れか１つのローラの回転駆動によって図中反時計回りに無端移動せしめられる。１次転写バイアスローラ９Ｙ，Ｍ，Ｃ，Ｋは、このように無端移動せしめられる中間転写ベルト８を感光体１Ｙ，Ｍ，Ｃ，Ｋとの間に挟み込んでそれぞれ１次転写ニップを形成している。これらは中間転写ベルト８の裏面（ループ内周面）にトナーとは逆極性（例えばプラス）の転写バイアスを印加する方式のものである。１次転写バイアスローラ９Ｙ，Ｍ，Ｃ，Ｋを除くローラは、全て電気的に接地されている。中間転写ベルト８は、その無端移動に伴ってＹ，Ｍ，Ｃ，Ｋ用の１次転写ニップを順次通過していく過程で、感光体１Ｙ，Ｍ，Ｃ，Ｋ上のＹ，Ｍ，Ｃ，Ｋトナー像が重ね合わせて１次転写される。これにより、中間転写ベルト８上に４色重ね合わせトナー像（以下、４色トナー像という）が形成される。   The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched around these three rollers. The primary transfer bias rollers 9Y, M, C, and K sandwich the intermediate transfer belt 8 moved endlessly in this manner from the photoreceptors 1Y, M, C, and K to form primary transfer nips, respectively. Yes. In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All of the rollers except the primary transfer bias rollers 9Y, 9M, 9C, and 9K are electrically grounded. The intermediate transfer belt 8 sequentially passes through the primary transfer nips for Y, M, C, and K along with the endless movement thereof, and Y, M, and C on the photoreceptors 1Y, M, C, and K are sequentially transferred. , K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

２次転写バックアップローラ１２は、２次転写ローラ１９との間に中間転写ベルト８を挟み込んで２次転写ニップを形成している。中間転写ベルト８上に形成された４色トナー像は、この２次転写ニップで転写紙Ｐに転写される。   The secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 between the secondary transfer roller 19 and forms a secondary transfer nip. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the transfer paper P at the secondary transfer nip.

２次転写ニップを通過した後の中間転写ベルト８には、転写紙Ｐに転写されなかった転写残トナーが付着している。これは、クリーニング装置１０によってクリーニングされる。   Untransferred toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the cleaning device 10.

２次転写ニップにおいては、転写紙Ｐが互いに順方向に表面移動する中間転写ベルト８と２次転写ローラ１９との間に挟まれて、レジストローラ対２８側とは反対方向に搬送される。２次転写ニップから送り出された転写紙Ｐは、定着装置２０のローラ間を通過する際に、加圧されたり加熱されたりすることで、表面に４色トナー像が定着せしめられる。   At the secondary transfer nip, the transfer paper P is sandwiched between the intermediate transfer belt 8 and the secondary transfer roller 19 whose surfaces move in the forward direction, and is conveyed in the opposite direction to the registration roller pair 28 side. The transfer paper P sent out from the secondary transfer nip is pressed or heated when passing between the rollers of the fixing device 20, whereby the four-color toner image is fixed on the surface.

その後、転写紙Ｐは、排紙ローラ対２９のローラ間を経て機外へと排出される。プリンタ本体の上面には、スタック部３０が形成されており、排紙ローラ対２９によって機外に排出された転写紙Ｐは、このスタック部３０に順次スタックされる。   Thereafter, the transfer paper P is discharged out of the apparatus through a pair of paper discharge rollers 29. A stack unit 30 is formed on the upper surface of the printer main body, and the transfer sheets P discharged to the outside by the discharge roller pair 29 are sequentially stacked on the stack unit 30.

中間転写ユニット１５と、これよりも上方にあるスタック部３０との間には、ボトル収容部３１が配設されている。このボトル収容部３１は、Ｙ，Ｍ，Ｃ，Ｋトナーを収容するトナーボトル３２Ｙ，Ｍ，Ｃ，Ｋを収容している。トナーボトル３２Ｙ，Ｍ＜Ｃ，Ｋ内のＹ，Ｍ，Ｃ，Ｋトナーは、それぞれ後述するトナー補給装置により、プロセスカートリッジ６Ｙ，Ｍ，Ｃ，Ｋの現像装置に適宜補給される。これらのトナーボトル３２Ｙ，Ｍ，Ｃ，Ｋと、プロセスカートリッジ６Ｙ，Ｍ，Ｃ，Ｋとはそれぞれ独立してプリンタ１００本体に脱着可能である。   A bottle container 31 is disposed between the intermediate transfer unit 15 and the stack unit 30 located above the intermediate transfer unit 15. The bottle storage unit 31 stores toner bottles 32Y, 32M, 32C, and 32K that store Y, M, C, and K toners. The Y, M, C, and K toners in the toner bottles 32Y, M <C, and K are appropriately supplied to the developing devices of the process cartridges 6Y, 6M, 6C, and 6K, respectively, by a toner supply device that will be described later. The toner bottles 32Y, 32M, 32C, and 32K and the process cartridges 6Y, 6M, 6C, and 6K can be attached to and detached from the main body of the printer 100 independently.

図３は、トナーボトル３２Ｙから現像装置５Ｙにトナーを補給するＹ用のトナー補給装置４０Ｙを部分的に示す部分斜視図である。プリンタ１００の筺体内において、トナーボトル３２Ｙ下方には、トナーボトル３２Ｙ内のＹトナーを現像装置５Ｙに供給するためのトナー補給装置４０Ｙが配設されている。プロセスカートリッジ６Ｙは、図中矢印α方向にスライド移動せしめられることで、プリンタ本体内にセットされる。このとき、スライド移動に伴って、トナー補給装置４０Ｙの搬送パイプ４３Ｙの先端部が現像装置５Ｙに設けられたパイプ通路５８Ｙに挿入される。そして、搬送パイプ４３Ｙの先端部に設けられたトナー排出口４５Ｙと、現像装置５Ｙのケーシングに設けられたトナー受入口６１Ｙとが対向する。   FIG. 3 is a partial perspective view partially showing a Y toner replenishing device 40Y for replenishing toner from the toner bottle 32Y to the developing device 5Y. In the housing of the printer 100, a toner replenishing device 40Y for supplying Y toner in the toner bottle 32Y to the developing device 5Y is disposed below the toner bottle 32Y. The process cartridge 6Y is set in the printer main body by being slid in the direction of arrow α in the drawing. At this time, as the slide moves, the leading end of the transport pipe 43Y of the toner replenishing device 40Y is inserted into a pipe passage 58Y provided in the developing device 5Y. The toner discharge port 45Y provided at the tip of the transport pipe 43Y and the toner receiving port 61Y provided in the casing of the developing device 5Y face each other.

円筒状のトナーボトル３２Ｙは、トナー補給装置４０Ｙにセットされた状態で図示しない駆動手段によって回転駆動せしめられる。すると、トナーボトル３２Ｙ内のＹトナーが、ボトル内壁に設けられた螺旋状の突起によってボトル底部側からボトル先端側に向けて搬送されて、ボトル先端部に設けられた図示しない開口からボトル外に排出される。排出されたＹトナーは、トナー補給装置４０Ｙのトナー受入部４８Ｙ内に受け入れられた後、搬送パイプ４３Ｙと、上述したトナー排出口４５Ｙと、現像装置５Ｙのトナー受入口６１Ｙとを経由して、現像装置５Ｙ内に補給される。   The cylindrical toner bottle 32Y is rotationally driven by a driving unit (not shown) in a state where it is set in the toner replenishing device 40Y. Then, the Y toner in the toner bottle 32Y is conveyed from the bottle bottom side toward the bottle front end side by the spiral protrusion provided on the inner wall of the bottle, and is released from the opening (not shown) provided in the bottle front end portion to the outside of the bottle. Discharged. The discharged Y toner is received in the toner receiving portion 48Y of the toner replenishing device 40Y, and then passes through the transport pipe 43Y, the toner discharge port 45Y, and the toner receiving port 61Y of the developing device 5Y. The toner is supplied into the developing device 5Y.

図４は、Ｙ用の現像装置５Ｙを感光体１Ｙの軸方向の一端側から示す拡大断面図である。また、図５は、上部カバーを外した状態の現像装置５Ｙを示す斜視図である。また、図６は、上部カバー及び現像ロール５１Ｙを取り外した状態の現像装置５Ｙを示す斜視図である。   FIG. 4 is an enlarged sectional view showing the developing device 5Y for Y from one end side in the axial direction of the photoreceptor 1Y. FIG. 5 is a perspective view showing the developing device 5Y with the upper cover removed. FIG. 6 is a perspective view showing the developing device 5Y with the upper cover and the developing roll 51Y removed.

これらの図において、現像装置５Ｙは、そのケーシングの開口から現像ロール５１Ｙの周面の一部を露出させている。この現像ロール５１Ｙは、図示しない駆動手段によって回転駆動せしめられる筒状の現像スリーブ５１ａＹと、これに連れ回らないように内包されるマグネットローラ５１ｂＹとを有している。   In these drawings, the developing device 5Y exposes a part of the peripheral surface of the developing roll 51Y from the opening of the casing. The developing roll 51Y includes a cylindrical developing sleeve 51aY that is rotationally driven by a driving unit (not shown), and a magnet roller 51bY that is included so as not to rotate.

マグネットローラ５１ｂは、周方向に並ぶ５つの磁極Ｐ１、Ｐ２、Ｐ３、Ｐ４及びＰ５を有している。これら磁極Ｐ１、Ｐ２、Ｐ３、Ｐ４及びＰ５において、磁極Ｐ３と磁極Ｐ４とは互いに同極性の磁界を発生させるものである。互いに隣り合う他の磁極の組み合わせは、それぞれ互いに異なる極性の磁界を発生させる。現像スリーブ５１ａの周囲であって且つ磁極Ｐ５に対向する領域には、スリーブ表面に担持された現像剤の層厚を規制する現像剤規制部材としての現像ドクタ５２Ｙが配設されている。 The magnet roller 51b has five magnetic poles P 1 , P 2 , P 3 , P 4 and P 5 arranged in the circumferential direction. In these magnetic poles P 1 , P 2 , P 3 , P 4 and P 5 , the magnetic pole P 3 and the magnetic pole P 4 generate magnetic fields having the same polarity. Combinations of other magnetic poles adjacent to each other generate magnetic fields having different polarities. The region facing to and pole P 5 a around the developing sleeve 51a, a developing doctor 52Y is provided as a developer regulating member for regulating the layer thickness of the developer carried on the sleeve surface.

現像スリーブ５１ａＹは、回転に伴って表面を無端移動させながら、第１現像剤収容部５３Ｙ内の現像剤を担持する現像剤担持体として機能している。具体的には、現像ロール５１Ｙの下方には、現像剤を収容する現像剤収容部が配設されており、この現像剤収容部は仕切壁５９Ｙによって第１現像剤収容部５３Ｙと第２現像剤収容部５４Ｙとに仕切られている。そして、第１現像剤収容部５３Ｙには、供給スクリュウ部材７０Ｙが回転可能に配設されている。また、第２現像剤収容部５４Ｙには、搬送スクリュウ部材７３Ｙが回転可能に配設されている。これらスクリュウ部材は何れも、両端部を図示しない軸受けによって回転可能に支持される軸部と、これの周面に螺旋状に突設せしめられた羽根部とを有している。   The developing sleeve 51aY functions as a developer carrying member that carries the developer in the first developer containing portion 53Y while moving the surface endlessly with rotation. Specifically, a developer accommodating portion that accommodates the developer is disposed below the developing roll 51Y, and this developer accommodating portion is separated from the first developer accommodating portion 53Y and the second development by the partition wall 59Y. It is partitioned off from the agent container 54Y. A supply screw member 70Y is rotatably disposed in the first developer accommodating portion 53Y. Further, a transport screw member 73Y is rotatably disposed in the second developer accommodating portion 54Y. Each of these screw members has a shaft portion that is rotatably supported at both ends by a bearing (not shown), and a blade portion that is spirally projected on the peripheral surface thereof.

現像ロール５１Ｙ、供給スクリュウ部材７０Ｙ、搬送スクリュウ部材７３Ｙは、互いに平行な姿勢をとるように現像装置５Ｙ内に配設されている。即ち、２つのスクリュウ部材は、現像ロール５１Ｙの表面移動方向と直交する方向であるロール軸線方向に延在するように配設されている。そして、供給スクリュウ部材７０Ｙを収容している第１現像剤収容部５３Ｙと、搬送スクリュウ部材７３Ｙを収容している第２現像剤収容部５４Ｙとは、上述したように、仕切壁５９Ｙによって仕切られている。但し、図６に示すように、両スクリュウ部材の軸線方向の両端部に対向する領域には、仕切り壁５９Ｙが設けられておらず、両現像剤収容部は、長手方向の一端部に設けられた第１連通口６２Ｙや、他端部に設けられた第２連通口６３Ｙを通じて互いに連通している。   The developing roll 51Y, the supply screw member 70Y, and the conveying screw member 73Y are disposed in the developing device 5Y so as to be parallel to each other. That is, the two screw members are disposed so as to extend in the roll axis direction that is a direction orthogonal to the surface movement direction of the developing roll 51Y. The first developer accommodating portion 53Y that accommodates the supply screw member 70Y and the second developer accommodating portion 54Y that accommodates the conveying screw member 73Y are partitioned by the partition wall 59Y as described above. ing. However, as shown in FIG. 6, the partition wall 59Y is not provided in a region facing both axial ends of both screw members, and both developer accommodating portions are provided at one end in the longitudinal direction. The first communication port 62Y and the second communication port 63Y provided at the other end communicate with each other.

先に図４に示したように、現像ロール５１Ｙを収容する現像部は、第１現像剤収容部５３Ｙの上方に配設されており、現像部と第１現像剤収容部５３Ｙとは、長手方向（図紙面に直交する方向）の全領域において互いに連通している。   As shown in FIG. 4, the developing unit that accommodates the developing roll 51Y is disposed above the first developer accommodating portion 53Y, and the developing portion and the first developer accommodating portion 53Y are long. They communicate with each other in the entire region in the direction (direction orthogonal to the drawing surface).

図５に示すように、現像装置５Ｙのトナー受入口６１Ｙから受け入れられた図示しないＹトナーは、まず、第２現像剤収容部５４Ｙ内における長手方向の一端側に補給されて図示しない現像剤に取り込まれる。このようにして新たなＹトナーを取り込んだ現像剤は、図中矢印Ｂで示すように、搬送スクリュウ部材７３Ｙの回転に伴って搬送スクリュウ部材７３Ｙの一端側から他端側に向けて搬送される。そして、第２現像剤収容部５４Ｙの長手方向の他端部において、第２連通口６３Ｙを通って第１現像剤収容部５３Ｙの他端側に進入する。   As shown in FIG. 5, the Y toner (not shown) received from the toner receiving port 61Y of the developing device 5Y is first supplied to one end side in the longitudinal direction in the second developer accommodating portion 54Y to become a developer (not shown). It is captured. The developer having taken in the new Y toner in this way is transported from one end side to the other end side of the transport screw member 73Y as the transport screw member 73Y rotates as indicated by an arrow B in the figure. . Then, at the other end portion in the longitudinal direction of the second developer accommodating portion 54Y, the second developer accommodating portion 54Y enters the other end side of the first developer accommodating portion 53Y through the second communication port 63Y.

第１現像剤収容部５３Ｙ内では、その他端側に進入してきた現像剤が供給スクリュウ部材７０Ｙの回転駆動に伴って他端側から一端側に搬送されながら、その一部が現像ロール５１Ｙに汲み上げられて現像に寄与する。現像ロール５１Ｙに汲み上げられなかった現像剤や、現像に寄与された後に現像ロール５１Ｙから第１現像剤収容部５３Ｙ内に戻された現像剤は、やがて第１現像剤収容部５３Ｙの一端部まで搬送される。そして、図６に示したように、第１連通口６２Ｙを通って第２現像剤収容部５４Ｙの一端部に進入する。   In the first developer accommodating portion 53Y, the developer that has entered the other end side is transported from the other end side to the one end side as the supply screw member 70Y rotates, and a part of the developer is pumped up to the developing roll 51Y. Contributes to development. The developer that has not been pumped up by the developing roll 51Y or the developer that has been contributed to the development and then returned from the developing roll 51Y into the first developer accommodating portion 53Y eventually reaches one end of the first developer accommodating portion 53Y. Be transported. Then, as shown in FIG. 6, the first developer port 54Y enters one end of the second developer accommodating portion 54Y through the first communication port 62Y.

このようにして、現像装置５Ｙ内においては、現像剤が第２現像剤収容部５４Ｙと第１現像剤収容部５３Ｙとの間で循環搬送される。そして、この循環搬送の過程において、第２現像剤収容部５４Ｙの他端部でＹトナーが補給される。   In this manner, in the developing device 5Y, the developer is circulated and conveyed between the second developer accommodating portion 54Y and the first developer accommodating portion 53Y. Then, in this circulating conveyance process, Y toner is replenished at the other end of the second developer accommodating portion 54Y.

先に示した図４において、第１現像剤収容部５３Ｙ内の現像剤中は、マグネットローラ５１ｂＹの磁極Ｐ４やＰ５の磁力によって現像ロール５１Ｙの現像スリーブ５１ａＹに向けて引き寄せられて、スリーブ表面に担持される。現像スリーブ５１ａＹ表面に担持された現像剤は、現像スリーブ５１ａＹの回転に伴ってスリーブ表面と現像ドクタ５２Ｙとの間に形成されるドクタギャップを通過する際に、スリーブ表面上における層厚が規制される。そして、感光体１に対向する現像領域に搬送されると、マグネットローラ５１ｂＹの磁極Ｐ１の磁力によって現像スリーブ５１ａＹ上で穂立ちした状態となる。 In Figure 4 shown above, the developer in the first developer accommodating section 53Y is attracted toward the developing sleeve 51aY of the developing roller 51Y by the magnetic force of the magnetic pole P 4 and P 5 of the magnet roller 51BY, the sleeve Supported on the surface. When the developer carried on the surface of the developing sleeve 51aY passes through a doctor gap formed between the sleeve surface and the developing doctor 52Y as the developing sleeve 51aY rotates, the layer thickness on the sleeve surface is regulated. The When it is conveyed to a developing region facing the photosensitive member 1 in a state of napped on the developing sleeve 51aY by the magnetic force of the magnetic poles P 1 of the magnet roller 51BY.

現像スリーブ５１ａＹは、現像領域において感光体１Ｙの表面よりも速い線速で同方向に移動する。そして、現像スリーブ５１ａＹ上で穂立ちした現像剤は、先端部を感光体１Ｙの表面に摺擦させながら移動する。現像ロール５１Ｙには、図示しない電源によって現像バイアスが印加されており、これによって現像領域には現像電界が形成される。そして、感光体１Ｙ上の静電潜像と現像スリーブ５１ａＹとの間では、現像剤中のＹトナーに対してスリーブ側から静電潜像側に向かう静電力が働く。これに対し、感光体１Ｙ上の非画像部（地肌部）と現像スリーブ５１ａＹとの間では、現像剤中のＹトナーに対して非画像部側からスリーブ側に向かう静電力が働く。これらの結果、現像領域では、感光体１上の静電潜像にＹトナーが選択的に付着して、静電潜像をＹトナー像に現像する。   The developing sleeve 51aY moves in the same direction at a linear velocity faster than the surface of the photoreceptor 1Y in the developing region. Then, the developer spiked on the developing sleeve 51aY moves while sliding the tip portion on the surface of the photoreceptor 1Y. A developing bias is applied to the developing roll 51Y by a power source (not shown), whereby a developing electric field is formed in the developing region. Then, between the electrostatic latent image on the photoconductor 1Y and the developing sleeve 51aY, an electrostatic force is exerted on the Y toner in the developer from the sleeve side toward the electrostatic latent image side. On the other hand, between the non-image portion (background portion) on the photoreceptor 1Y and the developing sleeve 51aY, an electrostatic force acting from the non-image portion side to the sleeve side acts on the Y toner in the developer. As a result, in the development area, Y toner selectively adheres to the electrostatic latent image on the photoreceptor 1 and develops the electrostatic latent image into a Y toner image.

なお、本プリンタにおいては、現像スリーブ５１ａＹが図示しないクラッチやギヤを介して駆動モータ（図２の４１Ｙ）に接続されており、このクラッチのオンオフによって、現像スリーブ５１ａＹの回転や回転停止が制御されるようになっている。   In this printer, the developing sleeve 51aY is connected to a drive motor (41Y in FIG. 2) via a clutch and a gear (not shown), and the rotation and stoppage of the developing sleeve 51aY are controlled by turning on and off the clutch. It has become so.

次に、従来の現像装置の構成について説明する。
図７は、従来のＹ用の現像装置５Ｙにおける供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。これらスクリュウ部材は、互いに現像剤を軸線の逆方向に搬送するように羽根部（７２Ｙ、７５Ｙ）の傾きが異なっている点の他が同様の構成になっている。軸線方向の長さ、軸部（７１Ｙ、７４Ｙ）の太さ、羽根部（７２Ｙ、７５Ｙ）の外径、羽根部のピッチが互いに同じである。 Next, the configuration of a conventional developing device will be described.
FIG. 7 is a perspective view showing a supply screw member 70Y and a conveying screw member 73Y in a conventional Y developing device 5Y. These screw members have the same configuration except that the inclination of the blade portions (72Y, 75Y) is different so as to convey the developer in the opposite directions of the axis. The length in the axial direction, the thickness of the shaft portions (71Y, 74Y), the outer diameter of the blade portions (72Y, 75Y), and the pitch of the blade portions are the same.

図８は、従来のＹ用の現像装置５Ｙを示す拡大模式図である。図中のハッチングは、現像剤が充填されている領域を示している。図示のように、従来の現像装置５Ｙでは、第１現像剤収容部５３Ｙ、第２現像剤収容部５４Ｙにそれぞれ同量の現像剤を充填していた。その充填量は、供給スクリュウ部材７０Ｙから現像ロール５１Ｙに対して現像剤を良好に供給し得るように、スクリュウ部材の高さよりも現像剤の高さを若干大きくする程度の量であった。   FIG. 8 is an enlarged schematic diagram showing a conventional Y developing device 5Y. The hatching in the figure indicates the region filled with the developer. As shown in the drawing, in the conventional developing device 5Y, the first developer container 53Y and the second developer container 54Y are filled with the same amount of developer, respectively. The filling amount was such that the height of the developer was slightly larger than the height of the screw member so that the developer could be satisfactorily supplied from the supply screw member 70Y to the developing roll 51Y.

次に、本実施形態に係るプリンタの特徴的な構成について説明する。
図９は、本プリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。また、図１０は、本プリンタにおける供給スクリュウ部材７０Ｙを示す縦断面図である。これらの図に示すように、供給スクリュウ部材７０Ｙは、軸部７１の軸線方向における中央部の径が両端部よりも大きくなっている。但し、供給スクリュウ部材７０Ｙの中央部と両端部とで、羽根部７２Ｙの外径は同じになっている。また、羽根部７２Ｙの軸線方向におけるピッチも、中央部と両端部とで同じになっている。 Next, a characteristic configuration of the printer according to the present embodiment will be described.
FIG. 9 is a perspective view showing the supply screw member 70Y and the conveying screw member 73Y in the developing device for Y of this printer. FIG. 10 is a longitudinal sectional view showing the supply screw member 70Y in the printer. As shown in these drawings, in the supply screw member 70Y, the diameter of the central portion in the axial direction of the shaft portion 71 is larger than both end portions. However, the outer diameter of the blade portion 72Y is the same between the central portion and both end portions of the supply screw member 70Y. The pitch in the axial direction of the blade portion 72Y is also the same at the center portion and both end portions.

かかる構成では、供給スクリュウ部材７０Ｙの軸部７１Ｙの軸線方向における中央部の径が両端部よりも大きくなっていることにより、図１１に点線のハッチングで示すように、供給スクリュウ部材７０Ｙの中央部における螺旋状の空間の容積が両端部よりも小さくなる。このため、中央部では、両端部に比べて、螺旋状の空間内に収まりきれずにスクリュウの外側に押し出される現像剤の量が多くなる。そして、供給スクリュウ部材７０Ｙと現像ロール（５１Ｙ）との間に介在する現像剤の量が両端部に比べて多くなる。これにより、供給スクリュウ部材７０Ｙの中央部が回転に伴って撓んでも、現像ロールの中央部に対して十分量の現像剤を汲み上げさせて、周期的な現像濃度ムラを抑えることができる。   In such a configuration, since the diameter of the central portion in the axial direction of the shaft portion 71Y of the supply screw member 70Y is larger than both end portions, the central portion of the supply screw member 70Y is shown by the dotted hatching in FIG. The volume of the spiral space in is smaller than both ends. For this reason, in the central portion, the amount of the developer that is pushed out to the outside of the screw without being contained in the spiral space is larger than in the both end portions. Then, the amount of the developer interposed between the supply screw member 70Y and the developing roll (51Y) becomes larger than both ends. As a result, even if the central portion of the supply screw member 70Y bends with rotation, a sufficient amount of developer can be pumped up to the central portion of the developing roll, and periodic development density unevenness can be suppressed.

図１２は、本実施形態に係るプリンタの現像装置（５Ｙ）の変形例装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。また、図１３は、同供給スクリュウ部材７０Ｙを示す縦断面図である。これらの図に示すように、この変形例装置では、供給スクリュウ部材７０Ｙとして、軸部７１Ｙの径を両端部から中央部に向けて段差なく徐々に大きくしたものを用いている。両端部から中央部に向けて径が徐々に大きくなっていくテーパーが軸部７１Ｙに設けられているのである。かかる構成では、供給スクリュウ部材７０Ｙの螺旋状の空間内に保持した現像剤を、軸部７１Ｙの端部側と中央部との境界で軸部７１Ｙの段差に引っ掛けることなく、スムーズに搬送することができる。これにより、現像剤を段差に引っ掛けることによる画質の劣化を回避することができる。   FIG. 12 is a perspective view showing a supply screw member 70Y and a conveying screw member 73Y in a modified device of the developing device (5Y) of the printer according to the present embodiment. FIG. 13 is a longitudinal sectional view showing the supply screw member 70Y. As shown in these drawings, in this modified apparatus, as the supply screw member 70Y, the diameter of the shaft portion 71Y is gradually increased from both end portions toward the central portion without any step. The taper 71Y is provided with a taper whose diameter gradually increases from both ends toward the center. In such a configuration, the developer held in the spiral space of the supply screw member 70Y is smoothly transported without being caught by the step of the shaft portion 71Y at the boundary between the end portion side and the center portion of the shaft portion 71Y. Can do. Thereby, it is possible to avoid the deterioration of the image quality due to the developer being caught on the step.

ところで、先に図８に示した従来の現像装置５Ｙにおいては、現像ロール５１Ｙの現像スリーブ５１ａＹに対して十分量の現像剤を汲み上げさせるように、供給スクリュウ部材７０Ｙやその周囲に比較的多量の現像剤を充填している。そして、このような充填により、現像剤に比較的高い圧力をかけて現像剤の劣化を早めてしまったり、駆動モータ（図２の４１Ｙ）の駆動トルクを高くしてしまったりするという不具合があった。   By the way, in the conventional developing device 5Y shown in FIG. 8, a relatively large amount of developer is pumped around the supply screw member 70Y and its surroundings so that a sufficient amount of developer is pumped up to the developing sleeve 51aY of the developing roll 51Y. Filled with developer. Such filling causes a problem that a relatively high pressure is applied to the developer to accelerate the deterioration of the developer or the drive torque of the drive motor (41Y in FIG. 2) is increased. It was.

また、第２現像剤収容部５４Ｙ内に補給されたＹトナーは、搬送スクリュウ部材７３Ｙの螺旋状の空間内に入り切れずにスクリュウの上に乗っている現像剤に取り込まれるが、この現像剤は羽根部（７５Ｙ）の螺旋運動の軌道内に存在しないことから、活発な挙動を示さない。このような現像剤に取り込まれたＹトナーは、搬送スクリュウ部材７３Ｙや磁性キャリアとの摺擦による摩擦帯電を起こし難い。このため、高画像面積率の画像が連続してプリントアウトされたときなどに、第２現像剤収容部５４Ｙ内に一時的に多量のＹトナーが補給されると、それが十分に摩擦帯電しないままに第１現像剤収容部５３Ｙ内まで搬送されて、いわゆる地汚れを引き起こし易かった。地汚れとは、帯電不良のトナーを感光体（１Ｙ）の地肌部に付着させてしまう現象である。   Further, the Y toner replenished in the second developer accommodating portion 54Y does not completely enter the spiral space of the conveying screw member 73Y and is taken into the developer on the screw. Is not in the orbit of the spiral motion of the blade (75Y), and therefore does not show active behavior. The Y toner taken in by such a developer hardly causes frictional charging due to sliding friction with the conveying screw member 73Y or the magnetic carrier. For this reason, when a large amount of Y toner is temporarily replenished into the second developer accommodating portion 54Y, for example, when an image with a high image area ratio is continuously printed out, it is not sufficiently frictionally charged. It was transported into the first developer accommodating portion 53Y as it was, and it was easy to cause so-called soiling. The background stain is a phenomenon in which poorly charged toner adheres to the background portion of the photoreceptor (1Y).

そこで、本実施形態に係るプリンタでは、供給スクリュウ部材７０Ｙによる単位時間あたりの現像剤搬送量を、搬送スクリュウ部材７３Ｙによる単位時間あたりの現像剤搬送量よりも少なくするような設定にしている。このような設定では、図１４に示すように、第２現像剤収容部５４Ｙよりも第１現像剤収容部５３Ｙ内に多くの現像剤が収容されるようになる。そして、第１現像剤収容部５３Ｙ内では、供給スクリュウ部材７０Ｙの螺旋状の空間内に保持し切れなくなった現像剤を、供給スクリュウ部材７０Ｙの上方に溢れさせることで、現像スリーブ５１ａＹに良好に汲み上げさせることができる。これに対し、第２現像剤収容部５４内では、全ての現像剤を搬送スクリュウ部材７３Ｙの螺旋状の空間内に保持させて、羽根部（７５Ｙ）の螺旋運動によって積極的に撹拌することが可能になる。これにより、新たに補給されたＹトナーを第１現像剤収容部５３Ｙ内まで搬送する前に良好に摩擦帯電せしめて、高画像面積率の画像の連続出力時においても、Ｙトナーの帯電不良による地汚れの発生を抑えることができる。   Therefore, in the printer according to the present embodiment, the developer transport amount per unit time by the supply screw member 70Y is set to be smaller than the developer transport amount per unit time by the transport screw member 73Y. In such a setting, as shown in FIG. 14, more developer is accommodated in the first developer accommodating portion 53Y than in the second developer accommodating portion 54Y. In the first developer accommodating portion 53Y, the developer that cannot be held in the spiral space of the supply screw member 70Y overflows above the supply screw member 70Y, so that the developing sleeve 51aY is satisfactorily provided. Can be pumped up. On the other hand, in the second developer accommodating portion 54, all the developer is held in the spiral space of the transport screw member 73Y and is actively stirred by the spiral motion of the blade portion (75Y). It becomes possible. As a result, the newly supplied Y toner is triboelectrically charged well before being transported into the first developer accommodating portion 53Y, and even during continuous output of an image with a high image area ratio, the Y toner is poorly charged. The occurrence of soiling can be suppressed.

なお、４つの現像装置のうち、Ｙ用の現像装置５Ｙだけについて詳述したが、他色用（Ｍ，Ｃ，Ｋ用）の現像装置も、Ｙ用の現像装置５Ｙと同様の構成になっている。   Of the four developing devices, only the Y developing device 5Y has been described in detail, but the developing devices for other colors (for M, C, and K) have the same configuration as the Y developing device 5Y. ing.

供給スクリュウ部材７０Ｙによる単位時間あたりの現像剤搬送量を、搬送スクリュウ部材７３Ｙよりも少なくする設定を実現する方法としては、様々な方法が挙げられる。例えば、搬送スクリュウ部材７３Ｙの回転速度を供給スクリュウ部材７０Ｙよりも速くすることで、前述のような設定が可能になる。また例えば、供給スクリュウ部材７０Ｙとして、１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙの１回転あたりにおける現像剤搬送量よりも少なくしたものを用いてもよい。但し、前者の方法では、搬送スクリュウ部材７３Ｙによる撹拌力が過剰になって現像剤の劣化を早めてしまったり、２つのスクリュウ部材に回転速度差を設けるための機構を複雑にしてしまったりするという不具合がある。そこで、本実施形態に係るプリンタでは、供給スクリュウ部材７０Ｙとして、１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも少なくしたものを用いることで、上述のような設定を行っている。   Various methods can be used as a method for realizing the setting in which the developer conveyance amount per unit time by the supply screw member 70Y is smaller than that of the conveyance screw member 73Y. For example, the above-described setting can be performed by making the rotation speed of the conveying screw member 73Y faster than the supply screw member 70Y. Further, for example, as the supply screw member 70Y, a developer conveyance amount per rotation smaller than the developer conveyance amount per rotation of the conveyance screw member 73Y may be used. However, in the former method, the stirring force by the conveying screw member 73Y becomes excessive, and the deterioration of the developer is accelerated, or the mechanism for providing the rotational speed difference between the two screw members is complicated. There is a bug. Therefore, in the printer according to the present embodiment, the above-described setting is performed by using a supply screw member 70Y having a developer conveyance amount per rotation smaller than that of the conveyance screw member 73Y.

次に、実施形態に係るプリンタに、より特徴的な構成を付加した各実施例のプリンタについて説明する。
［第１実施例］
図１５は、本第１実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第１実施例に係るプリンタでは、図示のように、供給スクリュウ部材７０Ｙとして、搬送スクリュウ部材７３Ｙよりも羽根部の外径を大きくしたものを用いている。かかる構成では、供給スクリュウ部材７０Ｙの回転に伴う現像剤の周方向の移動力を、より小径の搬送スクリュウ部材７３Ｙによる同移動力よりも大きくする。これにより、両方のスクリュウ部材をそれぞれ比較的大径にすることによる装置の大型化やコストアップを回避しながら、大径の供給スクリュウ部材７０Ｙの回転に伴って現像剤をスクリュウ側から現像スリーブ５１ａＹ側に向けて良好に移動させて、スリーブに対して現像剤を良好に汲み上げさせることができる。なお、両スクリュウ部材の回転速度は互いに同じである。 Next, printers according to the respective examples in which a more characteristic configuration is added to the printer according to the embodiment will be described.
[First embodiment]
FIG. 15 is a perspective view showing a supply screw member 70Y and a conveying screw member 73Y in the developing device for Y of the printer according to the first embodiment. In the printer according to the first embodiment, as illustrated, a supply screw member 70Y having an outer diameter of the blade portion larger than that of the transport screw member 73Y is used. In such a configuration, the moving force in the circumferential direction of the developer accompanying the rotation of the supply screw member 70Y is made larger than the moving force due to the smaller diameter conveying screw member 73Y. As a result, the developer is supplied from the screw side to the developing sleeve 51aY along with the rotation of the large-diameter supply screw member 70Y while avoiding the increase in size and cost of the apparatus due to the relatively large diameters of both screw members. The developer can be well pumped up to the sleeve by being moved well toward the side. The rotational speeds of both screw members are the same.

供給スクリュウ部材７０Ｙとしては、羽根部７２Ｙの軸線方向におけるピッチを搬送スクリュウ部材７３Ｙと同じにしているものの、羽根部７２Ｙの側面の面積を搬送スクリュウ部材７３Ｙのものよりも小さくしたものを用いている。羽根部のピッチが両スクリュウ部材で互いに同じであるので、羽根部側面の面積のより小さい供給スクリュウ部材７０Ｙの方が、１回転あたりにおける現像剤搬送量がより少なくなる。かかる構成では、両スクリュウ部材で羽根部のピッチを異ならせることなく、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも少なくすることができる。   As the supply screw member 70Y, although the pitch in the axial direction of the blade portion 72Y is the same as that of the conveying screw member 73Y, the supply screw member 70Y has a smaller area on the side surface of the blade portion 72Y than that of the conveying screw member 73Y. . Since the pitch of the blade portions is the same for both screw members, the supply screw member 70Y having a smaller area on the side surface of the blade portion has a smaller amount of developer transport per rotation. In such a configuration, the developer conveyance amount per rotation of the supply screw member 70Y can be made smaller than that of the conveyance screw member 73Y without making the pitch of the blade portions different between the two screw members.

また、本第１実施例に係るプリンタでは、供給スクリュウ部材７０Ｙとして、軸部７１Ｙにおける軸線方向の中央部及び両端部の径を何れも搬送スクリュウ部材７３Ｙの軸部７４Ｙの径よりも大きくしたものを用いている。これにより、羽根部７２Ｙの外径を搬送スクリュウ部材７３Ｙの羽根部７４Ｙの外径よりも大きくした構成を採用しても、供給スクリュウ部材７０Ｙの羽根部側面の面積を搬送スクリュウ部材７３Ｙのものよりも容易に小さくすることができる。   In the printer according to the first embodiment, as the supply screw member 70Y, the diameter of the central portion and both end portions in the axial direction of the shaft portion 71Y is larger than the diameter of the shaft portion 74Y of the transport screw member 73Y. Is used. Thereby, even if the structure which made the outer diameter of the blade | wing part 72Y larger than the outer diameter of the blade | wing part 74Y of the conveyance screw member 73Y is adopted, the area of the blade | wing part side surface of the supply screw member 70Y is larger than that of the conveyance screw member 73Y. Can be easily reduced.

［第２実施例］
図１６は、本第２実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第２実施例に係るプリンタにおいても、供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとで、互いに羽根部の軸線方向のピッチや回転速度を同じにしている。但し、図示のように、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙに切り欠き７７Ｙを設けたものを用いている。これにより、両スクリュウ部材で羽根部のピッチや回転速度を互いに同じにしつつ、羽根部の側面の１周あたりにおける面積を搬送スクリュウ部材７３Ｙよりも供給スクリュウ部材７０Ｙで小さくしている。かかる構成においても、両スクリュウ部材で羽根部のピッチを互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。 [Second Embodiment]
FIG. 16 is a perspective view showing the supply screw member 70Y and the transport screw member 73Y in the developing device for Y of the printer according to the second embodiment. Also in the printer according to the second embodiment, the supply screw member 70Y and the conveying screw member 73Y have the same pitch and rotational speed in the axial direction of the blade portions. However, as shown in the figure, the supply screw member 70Y is provided with a notch 77Y in the blade portion 72Y. Thereby, while the pitch and rotational speed of a blade | wing part are made the same mutually with both screw members, the area per circumference | surroundings of the side surface of a blade | wing part is made smaller by the supply screw member 70Y than the conveyance screw member 73Y. Even in this configuration, even if the pitch of the blade portions is the same between both screw members, it is possible to easily set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. .

［第３実施例］
図１７は、本第３実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第３実施例に係るプリンタにおいても、供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとで、互いに羽根部の軸線方向のピッチや回転速度を同じにしている。また、羽根部の外径も両スクリュウ部材で互いに同じにしている。但し、図示のように、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの厚みを搬送スクリュウ部材７３Ｙのものよりも大きくしたものを用いている。これにより、両スクリュウ部材で羽根部のピッチや外径を互いに同じにした条件で、供給スクリュウ部材７０Ｙにおける現像剤を保持可能な螺旋状の空間の容積を搬送スクリュウ部材７３Ｙのものよりも小さくしている。羽根部のピッチや外径が両スクリュウ部材で互いに同じであるので、螺旋状の空間のより小さい供給スクリュウ部材７０Ｙの方が、搬送スクリュウ部材７３Ｙよりも１回転あたりにおける現像剤搬送量が少なくなる。かかる構成においては、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。 [Third embodiment]
FIG. 17 is a perspective view showing the supply screw member 70Y and the transport screw member 73Y in the developing device for Y of the printer according to the third embodiment. Also in the printer according to the third embodiment, the supply screw member 70Y and the conveying screw member 73Y have the same pitch and rotational speed in the axial direction of the blade portions. The outer diameters of the blades are also the same for both screw members. However, as shown in the drawing, the supply screw member 70Y has a blade portion 72Y having a thickness larger than that of the conveying screw member 73Y. As a result, the volume of the spiral space capable of holding the developer in the supply screw member 70Y is made smaller than that of the conveying screw member 73Y under the condition that the pitches and outer diameters of the blade portions are the same in both screw members. ing. Since the pitch and outer diameter of the blade portions are the same for both screw members, the supply screw member 70Y having a smaller helical space has a smaller developer conveyance amount per rotation than the conveyance screw member 73Y. . In such a configuration, even if the pitches and outer diameters of the blade portions are the same between the two screw members, the setting for making the developer conveyance amount per rotation of the supply screw member 70Y smaller than that of the conveyance screw member 73Y is easily performed. be able to.

［第４実施例］
図１８は、本第４実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第４実施例に係るプリンタにおいても、供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとで、互いに羽根部の軸線方向のピッチや回転速度を同じにしている。また、羽根部の外径も両スクリュウ部材で互いに同じにしている。但し、図示のように、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙを２条設けたものを用いている。これに対し、搬送スクリュウ部材７３Ｙの羽根部７５Ｙの条数は１つである。即ち、本第４実施例に係るプリンタでは、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの条数を搬送スクリュウ部材７３Ｙよりも多くしたものを用いている。これにより、両スクリュウ部材で羽根部のピッチや外径を互いに同じにした条件で、供給スクリュウ部材７０Ｙにおける現像剤を保持可能な螺旋状の空間の容積を搬送スクリュウ部材７３Ｙのものよりも小さくしている。かかる構成においても、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。 [Fourth embodiment]
FIG. 18 is a perspective view showing the supply screw member 70Y and the conveying screw member 73Y in the developing device for Y of the printer according to the fourth embodiment. Also in the printer according to the fourth embodiment, the supply screw member 70Y and the conveying screw member 73Y have the same pitch and rotational speed in the axial direction of the blade portions. The outer diameters of the blades are also the same for both screw members. However, as shown in the drawing, the supply screw member 70Y is provided with two blade portions 72Y. In contrast, the number of blade portions 75Y of the conveying screw member 73Y is one. That is, in the printer according to the fourth embodiment, as the supply screw member 70Y, the supply blade member 70Y having a larger number of blades 72Y than the conveying screw member 73Y is used. As a result, the volume of the spiral space capable of holding the developer in the supply screw member 70Y is made smaller than that of the conveying screw member 73Y under the condition that the pitches and outer diameters of the blade portions are the same in both screw members. ing. Even in such a configuration, even if the pitches and outer diameters of the blade portions are the same between the two screw members, it is easy to set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. be able to.

［第５実施例］
図１９は、本第５実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第５実施例に係るプリンタにおいても、供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとで、互いに回転速度を同じにしている。また、羽根部の外径も両スクリュウ部材で互いに同じにしている。但し、図示のように、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの軸線方向における配設ピッチを搬送スクリュウ部材７３Ｙよりも小さくしたものを用いている。これにより、両スクリュウ部材で羽根部の外径や回転速度を互いに同じにした条件で、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも少なくしている。かかる構成においては、両スクリュウ部材で羽根部の外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。 [Fifth embodiment]
FIG. 19 is a perspective view showing a supply screw member 70Y and a conveying screw member 73Y in the developing device for Y of the printer according to the fifth embodiment. Also in the printer according to the fifth embodiment, the supply screw member 70Y and the transport screw member 73Y have the same rotational speed. The outer diameters of the blades are also the same for both screw members. However, as shown in the drawing, the supply screw member 70Y is used in which the arrangement pitch in the axial direction of the blade portion 72Y is smaller than that of the conveying screw member 73Y. Accordingly, the developer conveyance amount per rotation of the supply screw member 70Y is made smaller than that of the conveyance screw member 73Y under the condition that the outer diameters and the rotation speeds of the blade portions are the same between the two screw members. In such a configuration, even if the outer diameters of the blade portions are the same for both screw members, it is possible to easily set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. it can.

［第６実施例］
図２０は、本第６実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとを示す斜視図である。本第６実施例に係るプリンタにおいても、供給スクリュウ部材７０Ｙと搬送スクリュウ部材７３Ｙとで、互いに羽根部の軸線方向のピッチや回転速度を同じにしている。また、羽根部の外径も両スクリュウ部材で互いに同じにしている。但し、図示のように、供給スクリュウ部材７０Ｙとして、現像剤の螺旋方向への移動を阻害する板状の移動阻害部材７６Ｙを軸部７１Ｙ上に立設せしめたものを用いている。螺旋状の空間内に保持された現像剤が螺旋方向に移動しようとすると、この移動阻害部材７６Ｙに突き当たって、その螺旋方向への移動が阻害される。これにより、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。 [Sixth embodiment]
FIG. 20 is a perspective view showing the supply screw member 70Y and the conveying screw member 73Y in the developing device for Y of the printer according to the sixth embodiment. Also in the printer according to the sixth embodiment, the supply screw member 70Y and the conveying screw member 73Y have the same pitch and rotational speed in the axial direction of the blade portions. The outer diameters of the blades are also the same for both screw members. However, as shown in the drawing, as the supply screw member 70Y, a plate-like movement inhibition member 76Y that inhibits the movement of the developer in the spiral direction is erected on the shaft portion 71Y. When the developer held in the spiral space tries to move in the spiral direction, the developer abuts against the movement-inhibiting member 76Y and the movement in the spiral direction is inhibited. Thereby, even if the pitches and outer diameters of the blade portions are the same in both screw members, it is possible to easily set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. it can.

なお、移動阻害部材７６Ｙを軸部７１Ｙ上に立設せしめた例について説明したが、羽根部７２Ｙの対向側壁間に架け渡してもよい。また、これまで、現像装置をプロセスユニットに設けたプリンタの例について説明したが、感光体と現像装置とをそれぞれ個別に取り外すようにした画像形成装置にも、本発明の適用が可能である。   In addition, although the example in which the movement inhibiting member 76Y is erected on the shaft portion 71Y has been described, it may be bridged between the opposing side walls of the blade portion 72Y. The example of the printer in which the developing device is provided in the process unit has been described so far, but the present invention can also be applied to an image forming apparatus in which the photosensitive member and the developing device are individually detached.

以上、変形例装置においては、供給スクリュウ部材７０Ｙとして、軸部７１Ｙの径を両端部から中央部に向けて段差なく徐々に大きくしたものを用いているので、上述したように、供給スクリュウ部材７０Ｙの螺旋状の空間内に保持した現像剤を、軸部７１Ｙの段差に引っ掛けることなく、スムーズに搬送することができる。   As described above, in the modified device, as the supply screw member 70Y, the diameter of the shaft portion 71Y is gradually increased from both end portions toward the center portion without any step, so as described above, the supply screw member 70Y. The developer held in the spiral space can be smoothly conveyed without being caught by the step of the shaft portion 71Y.

また、実施形態や各実施例に係るプリンタにおいては、回転可能な軸部７４Ｙと、これの周面に螺旋状に突設せしめられた羽根部７５Ｙとを有するスクリュウ部材であって、且つ自らの回転に伴って現像剤を回転軸線方向に搬送しながら供給スクリュウ部材７０Ｙの軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すスクリュウ部材である搬送スクリュウ部材７３Ｙを設けている。そして、供給スクリュウ部材７０Ｙの軸線方向における現像剤搬送方向下流側の端部箇所まで搬送された現像剤を、搬送スクリュウ部材７３Ｙの軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すようにしている。更には、供給スクリュウ部材７０Ｙによる単位時間あたりの現像剤搬送量を搬送スクリュウ部材７３Ｙによる単位時間あたりの現像剤搬送量よりも少なくする設定を採用している。かかる構成では、第２現像剤収容部５４Ｙ内の現像剤収容量を第１現像剤収容部５３Ｙよりも少なくすることで、従来よりも現像装置内の現像剤充填量を減らして、駆動モータの駆動トルクを低くしたり、現像剤の劣化を抑えたりすることができる。更には、上述したように、第２現像剤収容部５４Ｙ内に新たに補給したＹトナーを第１現像剤収容部５３Ｙ内まで搬送する前に良好に摩擦帯電せしめて、高画像面積率の画像の連続出力時においても、Ｙトナーの帯電不良による地汚れの発生を抑えることができる。   Further, in the printer according to the embodiment and each example, a screw member having a rotatable shaft portion 74Y and a blade portion 75Y projecting spirally on the peripheral surface of the shaft portion 74Y. A conveyance screw member 73Y is provided as a screw member that delivers the developer in the rotation axis direction along with the rotation and delivers it to the upstream end portion in the developer conveyance direction in the axial direction of the supply screw member 70Y. Then, the developer transported to the end portion on the downstream side in the developer transport direction in the axial direction of the supply screw member 70Y is delivered to the end portion on the upstream side in the developer transport direction in the axial direction of the transport screw member 73Y. I have to. Furthermore, a setting is adopted in which the developer transport amount per unit time by the supply screw member 70Y is smaller than the developer transport amount per unit time by the transport screw member 73Y. In such a configuration, the developer storage amount in the second developer storage portion 54Y is smaller than that in the first developer storage portion 53Y, so that the developer filling amount in the developing device can be reduced as compared with the conventional case, and the drive motor The driving torque can be lowered and the deterioration of the developer can be suppressed. Furthermore, as described above, the Y toner newly replenished in the second developer accommodating portion 54Y is well frictionally charged before being conveyed into the first developer accommodating portion 53Y, so that an image with a high image area ratio is obtained. Even during the continuous output, it is possible to suppress the occurrence of background contamination due to Y toner charging failure.

また、第１実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、搬送スクリュウ部材７３Ｙよりも羽根部の外径を大きくしたものを用いている。かかる構成では、上述したように、両方のスクリュウ部材をそれぞれ比較的大径にすることによる装置の大型化やコストアップを回避しながら、大径の供給スクリュウ部材７０Ｙの回転に伴って現像剤をスクリュウ側から現像スリーブ５１ａＹ側に向けて良好に移動させて、スリーブに対して現像剤を良好に汲み上げさせることができる。   Further, in the printer according to the first embodiment, a supply screw member 70Y having an outer diameter of the blade portion larger than that of the conveying screw member 73Y is used. In this configuration, as described above, the developer is increased along with the rotation of the large-diameter supply screw member 70Y while avoiding the increase in size and cost of the apparatus due to the relatively large diameters of both screw members. The developer can be favorably moved from the screw side toward the developing sleeve 51aY side, and the developer can be pumped up satisfactorily with respect to the sleeve.

また、実施形態や各実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙの１回転あたりにおける現像剤搬送量よりも少なくしたものを用いている。かかる構成では、両スクリュウ部材の回転速度を互いに異ならせることによる現像剤の劣化の早まりや駆動機構の複雑化を回避しつつ、供給スクリュウ部材７０Ｙの単位時間あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも少なくすることができる。   Further, in the printer according to the embodiment and each example, the supply screw member 70Y uses a developer conveyance amount per rotation smaller than the developer conveyance amount per rotation of the conveyance screw member 73Y. Yes. In such a configuration, the developer conveyance amount per unit time of the supply screw member 70Y can be determined while avoiding the rapid deterioration of the developer and the complexity of the drive mechanism caused by making the rotation speeds of the two screw members different from each other. It can be less than 73Y.

また、第１実施例や第２実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、羽根部７１Ｙの側面の面積を搬送スクリュウ部材７３Ｙのものよりも小さくしたものを用いている。かかる構成では、上述したように、両スクリュウ部材で羽根部のピッチを異ならせることなく、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも少なくすることができる。   In the printers according to the first and second embodiments, the supply screw member 70Y uses a side surface area of the blade portion 71Y smaller than that of the conveying screw member 73Y. In this configuration, as described above, the developer conveyance amount per rotation of the supply screw member 70Y can be made smaller than that of the conveyance screw member 73Y without changing the pitch of the blade portions between the two screw members.

また、第１実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、搬送スクリュウ部材７３Ｙよりも羽根部の外径を大きくし、且つ軸部７１Ｙにおける中央部及び両端部の径を何れも搬送スクリュウ部材７３Ｙの軸部７４Ｙの径よりも大きくしたものを用いている。かかる構成では、上述したように、羽根部７２Ｙの外径を搬送スクリュウ部材７３Ｙの羽根部７４Ｙの外径よりも大きくした構成を採用しても、供給スクリュウ部材７０Ｙの羽根部側面の面積を搬送スクリュウ部材７３Ｙのものよりも容易に小さくすることができる。   In the printer according to the first embodiment, as the supply screw member 70Y, the outer diameter of the blade portion is made larger than that of the conveying screw member 73Y, and the diameters of the central portion and both end portions of the shaft portion 71Y are both conveying screws. A member 73Y having a diameter larger than that of the shaft portion 74Y is used. In such a configuration, as described above, even if the configuration in which the outer diameter of the blade portion 72Y is larger than the outer diameter of the blade portion 74Y of the conveying screw member 73Y is adopted, the area of the blade portion side surface of the supply screw member 70Y is conveyed. It can be easily made smaller than that of the screw member 73Y.

また、第２実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙに切り欠き７７Ｙを設けたものを用いている。かかる構成においても、両スクリュウ部材で羽根部のピッチを互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。   Further, in the printer according to the second embodiment, a supply screw member 70Y having a blade portion 72Y provided with a notch 77Y is used. Even in this configuration, even if the pitch of the blade portions is the same between both screw members, it is possible to easily set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. .

また、第３実施例や第４実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、現像剤を保持可能な螺旋状の空間の容積を搬送スクリュウ部材７３Ｙのものよりも小さくしたものを用いている。かかる構成では、螺旋状の空間の容積の違いにより、両スクリュウ部材間で単位時間あたりの現像剤搬送量を異ならせることができる。   Further, in the printers according to the third and fourth embodiments, the supply screw member 70Y uses a spiral space that can hold the developer with a volume smaller than that of the conveyance screw member 73Y. Yes. In such a configuration, the developer conveyance amount per unit time can be varied between the screw members due to the difference in volume of the spiral space.

また、第３実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの厚みを搬送スクリュウ部材７３Ｙのものよりも大きくしたものを用いている。かかる構成では、上述したように、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。   In the printer according to the third embodiment, as the supply screw member 70Y, a blade portion 72Y having a thickness greater than that of the conveying screw member 73Y is used. In such a configuration, as described above, even if the pitch and outer diameter of the blade portions are the same for both screw members, the developer conveyance amount per rotation of the supply screw member 70Y is set to be smaller than that of the conveyance screw member 73Y. Can be easily performed.

また、第４実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの条数を搬送スクリュウ部材７３Ｙにおける条数よりも多くしたものを用いている。かかる構成においても、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。   Further, in the printer according to the fourth embodiment, the supply screw member 70Y uses a number of blades 72Y that is greater than the number of threads in the transport screw member 73Y. Even in such a configuration, even if the pitches and outer diameters of the blade portions are the same between the two screw members, it is easy to set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. be able to.

また、第５実施例に係るプリンタにおいては、供給スクリュウ部材７０Ｙとして、羽根部７２Ｙの軸線方向における配設ピッチを搬送スクリュウ部材７３Ｙのものよりも小さくしたものを用いている。かかる構成では、上述したように、両スクリュウ部材で羽根部の外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。   In the printer according to the fifth embodiment, a supply screw member 70Y having an arrangement pitch in the axial direction of the blade portion 72Y smaller than that of the conveying screw member 73Y is used. In this configuration, as described above, even if the outer diameters of the blade portions are the same for both screw members, it is easy to set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. Can be done.

また、第６実施例に係るプリンタにおいては、スクリュウ部材７０Ｙとして、現像剤の螺旋方向への移動を阻害する移動阻害部材７６Ｙを軸部７１Ｙに設けたものを用いている。かかる構成においても、両スクリュウ部材で羽根部のピッチや外径を互いに同じにしても、供給スクリュウ部材７０Ｙの１回転あたりにおける現像剤搬送量を搬送スクリュウ部材７３Ｙよりも小さくする設定を容易に行うことができる。   In the printer according to the sixth embodiment, the screw member 70Y is provided with a movement inhibiting member 76Y that inhibits the movement of the developer in the spiral direction on the shaft portion 71Y. Even in such a configuration, even if the pitches and outer diameters of the blade portions are the same between the two screw members, it is easy to set the developer conveyance amount per rotation of the supply screw member 70Y to be smaller than that of the conveyance screw member 73Y. be able to.

また、実施形態や各実施例に係るプリンタにおいては、プロセスユニットを複数設けるとともに、各プロセスユニットの潜像担持体たる感光体上で現像された可視像としてのトナー像を転写体たる中間転写ベルト８に重ね合わせて転写する転写手段である中間転写ユニット１５を設けている。かかる構成では、重ね合わせの転写によって多色トナー像を形成することができる。   In the printer according to the embodiment or each example, a plurality of process units are provided, and a toner image as a visible image developed on a photosensitive member as a latent image carrier of each process unit is an intermediate transfer as a transfer member. An intermediate transfer unit 15 is provided as a transfer means for transferring the image superimposed on the belt 8. With this configuration, a multicolor toner image can be formed by superimposing transfer.

実施形態に係るプリンタを示す概略構成図。1 is a schematic configuration diagram illustrating a printer according to an embodiment. 同プリンタにおけるＹ用のプロセスユニットを示す拡大構成図。FIG. 3 is an enlarged configuration diagram illustrating a process unit for Y in the printer. 同プリンタのＹ用のトナーボトルと、同プロセスユニットの現像装置と、Ｙ用のトナー補給装置とを示す部分斜視図。FIG. 3 is a partial perspective view illustrating a toner bottle for Y of the printer, a developing device of the process unit, and a toner replenishing device for Y. 同現像装置を感光体の軸方向の一端側から示す拡大断面図。FIG. 3 is an enlarged sectional view showing the developing device from one end side in the axial direction of the photosensitive member. 上部カバーを外した状態の同現像装置を示す斜視図。FIG. 3 is a perspective view showing the developing device with an upper cover removed. 上部カバー及び現像ロールを取り外した状態の同現像装置を示す斜視図。FIG. 3 is a perspective view showing the developing device with an upper cover and a developing roll removed. 従来のＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and conveyance screw member in the conventional developing device for Y. 従来のＹ用の現像装置を示す拡大模式図。The expansion schematic diagram which shows the conventional developing device for Y. 実施形態に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on embodiment. 同供給スクリュウ部材を示す縦断面図。The longitudinal cross-sectional view which shows the supply screw member. 同供給スクリュウ部材を部分的に示す拡大側面図。The enlarged side view which shows the supply screw member partially. 変形例装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and conveyance screw member in a modification apparatus. 同供給スクリュウ部材を示す縦断面図。The longitudinal cross-sectional view which shows the supply screw member. 実施形態に係るプリンタの現像装置を示す拡大構成図。FIG. 3 is an enlarged configuration diagram illustrating a developing device of the printer according to the embodiment. 第１実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on 1st Example. 第２実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on 2nd Example. 第３実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on 3rd Example. 第４実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and conveyance screw member in the developing device for Y of the printer which concerns on 4th Example. 第５実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on 5th Example. 第６実施例に係るプリンタのＹ用の現像装置における供給スクリュウ部材と搬送スクリュウ部材とを示す斜視図。The perspective view which shows the supply screw member and the conveyance screw member in the developing device for Y of the printer which concerns on 6th Example.

符号の説明Explanation of symbols

１Ｙ，Ｍ，Ｃ，Ｋ：感光体（潜像担持体）
５Ｙ：現像装置
６Ｙ，Ｍ，Ｃ，Ｋ：プロセスユニット
８：中間転写ベルト（転写体）
１５：中間転写ユニット（転写手段）
５１ａＹ：現像スリーブ（現像剤担持体）
７０Ｙ：供給スクリュウ部材
７１Ｙ：軸部
７２Ｙ：羽根部
７３Ｙ：搬送スクリュウ部材
７４Ｙ：軸部
７５Ｙ：羽根部
７６Ｙ：移動阻害部材
７７Ｙ：切り欠き 1Y, M, C, K: photoconductor (latent image carrier)
5Y: Developing device 6Y, M, C, K: Process unit 8: Intermediate transfer belt (transfer body)
15: Intermediate transfer unit (transfer means)
51aY: Development sleeve (developer carrier)
70Y: Supply screw member 71Y: Shaft portion 72Y: Blade portion 73Y: Conveying screw member 74Y: Shaft portion 75Y: Blade portion 76Y: Movement inhibition member 77Y: Notch

Claims (17)

無端移動する表面に現像剤を担持する現像剤担持体と、該現像剤担持体の表面の無端移動方向と直交する方向に延在するように配設され、自らの回転に伴って現像剤を該方向に搬送しながら該現像剤担持体の表面に供給する供給スクリュウ部材とを備えるとともに、回転可能な軸部と、これの周面に螺旋状に突設せしめられた羽根部とを該供給スクリュウ部材に有し、該現像剤担持体に担持した現像剤によって潜像担持体上の潜像を現像する現像装置において、
上記供給スクリュウ部材として、上記搬送されている現像剤が上記現像剤担持体に受け渡される領域に存在する上記軸部の軸線方向における中央部の径を、両端部よりも大きくし、且つ該中央部と該両端部とで上記羽根部の外径を同じにしたものを用いたことを特徴とする現像装置。 A developer carrier that carries the developer on the surface that moves endlessly, and a surface that extends in a direction perpendicular to the direction of endless movement of the surface of the developer carrier, and the developer is loaded along with its rotation. A supply screw member that supplies the developer carrying member to the surface of the developer carrying member while transporting in the direction, and that includes a rotatable shaft portion and a blade portion that spirally protrudes from the peripheral surface of the supply shaft member. In a developing device that has a screw member and develops a latent image on a latent image carrier with a developer carried on the developer carrier,
As the feed screw member, the diameter of the central portion in the axial direction of the shaft portion which the developer being the transfer is present in the region to be passed to the developer carrying member, and larger than both end portions, and the central And a developing device using the same outer diameter of the blade portion at both ends. 請求項１の現像装置において、
上記供給スクリュウ部材として、上記軸部の径を両端部から中央部に向けて段差なく徐々に大きくしたものを用いたことを特徴とする画像形成装置。 The developing device according to claim 1.
2. An image forming apparatus according to claim 1, wherein the supply screw member is formed by gradually increasing the diameter of the shaft portion from both ends toward the central portion without any step. 請求項１又は２の現像装置において、
回転可能な軸部と、これの周面に螺旋状に突設せしめられた羽根部とを有するスクリュウ部材であって、且つ自らの回転に伴って現像剤を回転軸線方向に搬送しながら上記供給スクリュウ部材の軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すスクリュウ部材である搬送スクリュウ部材を設けるとともに、該供給スクリュウ部材の軸線方向における現像剤搬送方向下流側の端部箇所まで搬送された現像剤を、該搬送スクリュウ部材の軸線方向における現像剤搬送方向上流側の端部箇所に受け渡すようにし、該供給スクリュウ部材による単位時間あたりの現像剤搬送量を該搬送スクリュウ部材による単位時間あたりの現像剤搬送量よりも少なくしたことを特徴とする現像装置。 The developing device according to claim 1 or 2,
A screw member having a rotatable shaft portion and a blade portion projecting spirally on the peripheral surface of the shaft portion, and supplying the developer while transporting the developer in the direction of the rotation axis along with its rotation. A conveying screw member, which is a screw member that is delivered to an upstream end portion in the developer conveying direction in the axial direction of the screw member, is provided and conveyed to an end portion downstream in the developer conveying direction in the axial direction of the supply screw member The transferred developer is transferred to an end portion on the upstream side in the developer conveyance direction in the axial direction of the conveyance screw member, and the developer conveyance amount per unit time by the supply screw member is a unit by the conveyance screw member. A developing device characterized in that it is less than the developer transport amount per hour. 請求項３の現像装置において、
上記供給スクリュウ部材として、上記搬送スクリュウ部材よりも上記羽根部の外径を大きくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 3.
A developing device using the supply screw member having an outer diameter of the blade portion larger than that of the conveying screw member. 請求項３又は４の現像装置において、
上記供給スクリュウ部材として、１回転あたりにおける現像剤搬送量を上記搬送スクリュウ部材の１回転あたりにおける現像剤搬送量よりも少なくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 3 or 4,
2. A developing apparatus according to claim 1, wherein the supply screw member has a developer conveyance amount per rotation smaller than a developer conveyance amount per rotation of the conveyance screw member. 請求項５の現像装置において、
上記供給スクリュウ部材として、上記羽根部の側面の面積を上記搬送スクリュウ部材における該面積よりも小さくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 5.
A developing device using the supply screw member having a side surface area of the blade portion smaller than the area of the conveying screw member. 請求項６の現像装置において、
上記供給スクリュウ部材として、上記搬送スクリュウ部材よりも上記羽根部の外径を大きくし、且つ上記軸部における上記中央部及び両端部の径を何れも該搬送スクリュウ部材の軸部の径よりも大きくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 6.
As the supply screw member, the outer diameter of the blade portion is made larger than that of the conveying screw member, and the diameters of the central portion and both end portions of the shaft portion are both larger than the diameter of the shaft portion of the conveying screw member. A developing device using the above-mentioned one. 請求項６の現像装置において、
上記供給スクリュウ部材として、上記羽根部に切り欠きを設けたものを用いたことを特徴とする現像装置。 The developing device according to claim 6.
2. A developing device according to claim 1, wherein the supply screw member is a blade provided with a notch. 請求項５の現像装置において、
上記供給スクリュウ部材として、現像剤を保持可能な螺旋状の空間の容積を上記搬送スクリュウ部材における該容積よりも小さくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 5.
A developing device using the supply screw member having a helical space capable of holding a developer smaller than the volume of the conveying screw member. 請求項９の現像装置において、
上記供給スクリュウ部材として、上記羽根部の厚みを上記搬送スクリュウ部材における該厚みよりも大きくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 9.
A developing device using the supply screw member having a thickness of the blade portion larger than the thickness of the conveying screw member. 請求項９又は１０の現像装置において、
上記供給スクリュウ部材として、上記羽根部の条数を上記搬送スクリュウ部材における該条数よりも多くしたものを用いたことを特徴とする現像装置。 The developing device according to claim 9 or 10,
2. A developing device according to claim 1, wherein the supply screw member has a number of wings greater than that of the conveying screw member. 請求項５の現像装置において、
上記供給スクリュウ部材として、上記羽根部の軸線方向における配設ピッチを上記搬送スクリュウ部材における該配設ピッチよりも小さくしたものを用いたことを特徴とする現像装置。 The developing device according to claim 5.
2. A developing device according to claim 1, wherein the supply screw member has an arrangement pitch of the blades in the axial direction smaller than the arrangement pitch of the conveying screw member. 請求項５の現像装置において、
上記スクリュウ部材として、現像剤の螺旋方向への移動を阻害する移動阻害部材を上記軸部又は羽根部に設けたものを用いたことを特徴とする現像装置。 The developing device according to claim 5.
A developing device using, as the screw member, a member in which a movement-inhibiting member that inhibits movement of the developer in the spiral direction is provided in the shaft portion or the blade portion. 潜像を担持する潜像担持体と、該潜像担持体に担持される潜像を現像する現像装置とを用いて画像を形成する画像形成装置に搭載され、少なくとも該潜像担持体及び現像装置を１つのユニットとして共通の保持体で保持しながら画像形成装置本体に対して着脱されるプロセスユニットにおいて、
上記現像装置として、請求項１乃至１３の何れかの現像装置を用いたことを特徴とするプロセスユニット。 A latent image carrier that carries a latent image and a developing device that develops the latent image carried on the latent image carrier are mounted on an image forming apparatus that forms an image, and at least the latent image carrier and the developer In a process unit that is attached to and detached from the image forming apparatus main body while holding the apparatus as a single unit with a common holder,
14. A process unit using the developing device according to claim 1 as the developing device. 潜像担持体及びこれに担持される潜像を現像する現像装置を有するプロセスユニットを用いて画像を形成する画像形成装置において、
上記プロセスユニットとして、請求項１４のプロセスユニットを用いたことを特徴とする画像形成装置。 In an image forming apparatus for forming an image using a process unit having a latent image carrier and a developing device for developing a latent image carried on the latent image carrier,
An image forming apparatus using the process unit according to claim 14 as the process unit. 請求項１５の画像形成装置において、
上記プロセスユニットを複数設けるとともに、各プロセスユニットの潜像担持体上で現像された可視像を転写体に重ね合わせて転写する転写手段を設けたことを特徴とする画像形成装置。 The image forming apparatus according to claim 15.
An image forming apparatus comprising: a plurality of process units; and a transfer unit that transfers a visible image developed on a latent image carrier of each process unit in a superimposed manner on a transfer body. 潜像を担持する潜像担持体と、該潜像担持体に担持される潜像を現像する現像装置とを用いて画像を形成する画像形成装置において、
上記現像装置として、請求項１乃至１３の何れかの現像装置を用いたことを特徴とする画像形成装置。 In an image forming apparatus that forms an image using a latent image carrier that carries a latent image and a developing device that develops the latent image carried on the latent image carrier,
An image forming apparatus using the developing device according to claim 1 as the developing device.
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