JP2007127907A - Image forming apparatus - Google Patents

Image forming apparatus Download PDF

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JP2007127907A
JP2007127907A JP2005321629A JP2005321629A JP2007127907A JP 2007127907 A JP2007127907 A JP 2007127907A JP 2005321629 A JP2005321629 A JP 2005321629A JP 2005321629 A JP2005321629 A JP 2005321629A JP 2007127907 A JP2007127907 A JP 2007127907A
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developer
developing
toner
image forming
range
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JP4628932B2 (en
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Yoshio Hattori
Shunji Kato
Hideki Kimura
Katsumi Masuda
Kenji Nakajima
Kiyotaka Sakai
Hideo Yoshizawa
研二 中島
俊次 加藤
秀男 吉沢
清敬 堺
克己 増田
良雄 服部
秀樹 木村
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Ricoh Co Ltd
株式会社リコー
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer carrier which is a developing sleeve having twill line-like grooves and can suppress a reduction in the amount of a held developer over time. <P>SOLUTION: The developer carrier having twill line-like grooves is formed in such a way that a plurality of grooves extending in a direction inclined at a sharp angle to a rotation thrust direction intersect with a plurality of grooves extending in a direction inclined at a sharp angle to a direction opposite to the thrust direction, wherein any of the plurality of grooves has an angle of gradient to the thrust direction in the range of >0 to 40°. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、複写機、プリンタ、ファクシミリ等の画像形成装置において感光体上に形成した潜像をトナーを付着させ可視像化するのに用いる現像スリーブ、この現像スリーブを備える現像装置、この現像装置を備えるプロセスカートリッジ、及び、画像形成装置に関する。   The present invention relates to a developing sleeve used for making a latent image formed on a photosensitive member a visible image by attaching a toner to an image forming apparatus such as a copying machine, a printer, and a facsimile, a developing device including the developing sleeve, and a developing device. The present invention relates to a process cartridge including the apparatus and an image forming apparatus.

最近の複写機、プリンタは高画質、高信頼、高安定性に対する要求が非常に高い。これらを満足させるには現像剤担持体上の現像剤量の経時安定性及び均一性が重要なポイントとなる。従来は、サンドブラストによって表面に凹凸を形成した現像スリーブや現像ローラ回転軸に対して平行に延びる複数のV溝を表面に形成した現像スリーブを一般的に使用していた。サンドブラストを用いて凹凸を持たせた現像スリーブは、凹凸量が小さいと現像剤搬送能力が低下し、現像剤搬送能力を上げる為に凹凸量を大きくすると、加工時に現像スリーブを変形させるという問題があった。また、V溝を備えた現像スリーブは、現像剤規制部材に対して平行な各現像剤搬送溝の各部が同じ瞬間に規制部材上を通過するため、現像剤へ与えるストレスが大きいという問題があった。また、加工時の溝偏差に起因してスリーブ一周ピッチの汲み上げ量のムラが発生するという問題もあった。特許文献1〜4に記載の現像スリーブは、このような従来の技術課題を解決できる可能性がある。これらの現像スリーブは、あやめ状の溝が形成された現像スリーブである。   Recent copiers and printers have very high demands for high image quality, high reliability, and high stability. In order to satisfy these requirements, the temporal stability and uniformity of the developer amount on the developer carrying member are important points. Conventionally, a developing sleeve in which irregularities are formed on the surface by sandblasting and a developing sleeve in which a plurality of V-grooves extending in parallel with the rotation axis of the developing roller are formed on the surface are generally used. Developer sleeves with irregularities using sandblasting have a problem in that the developer conveying ability decreases if the irregularity amount is small, and if the irregularity amount is increased to increase the developer conveying ability, the developing sleeve is deformed during processing. there were. In addition, the developing sleeve provided with the V-groove has a problem that a large stress is applied to the developer because each portion of each developer conveying groove parallel to the developer regulating member passes over the regulating member at the same moment. It was. In addition, there is a problem that unevenness in the pumping amount of the sleeve circumferential pitch occurs due to the groove deviation at the time of processing. The developing sleeves described in Patent Documents 1 to 4 may solve such conventional technical problems. These developing sleeves are developing sleeves in which iris-like grooves are formed.

特開2003−316146号公報JP 2003-316146 A 特開2003−208012号公報JP 2003-208021 A 特開2000−242073号公報JP 2000-242073 A 特開平07−13410号公報Japanese Unexamined Patent Publication No. 07-13410

しかしながら、あやめ状の溝を形成した現像スリーブを用いる場合には、あやめ状の溝の具体的な条件によっては、経時での現像剤搬送量の低下が、回転軸に対して平行なV溝を形成した現像スリーブに比して顕著であるということがわかった。
また、あやめ状の溝の具体的な条件によっては現像スリーブの周方向(回転方向)の所定のピッチで、スラスト方向に延びる現像濃度が高い部分が生じて横の黒スジ状に見える異常画像(以下、ピッチ状横黒スジという)が発生することがわかった。また、あやめ状の溝の具体的な条件によっては現像スリーブの周方向(回転方向)の所定のピッチで、スラスト方向に延びる現像濃度が高い部分が生じて横の黒スジ状に見える異常画像(以下、ピッチ状横黒スジという)が発生することがわかった。
本発明は、上記問題に鑑みなされたものであり、その目的とするところは、あやめ状の溝を有しながら経時の現像剤搬送量低下を抑制できる現像剤担持体、この現像剤担持体を備える現像装置、この現像装置を備えるプロセスカートリッジ、及び、画像形成装置を提供することである。
他の目的は、更に、上記ピッチ状横黒スジや上記ピッチ状横黒スジの発生を抑制できる現像剤担持体、この現像剤担持体を備える現像装置、この現像装置を備えるプロセスカートリッジ、及び、画像形成装置を提供することである。
However, when a developing sleeve having an iris groove is used, depending on the specific conditions of the iris groove, a decrease in developer conveyance amount over time may occur due to a V groove parallel to the rotation axis. It was found that this was remarkable as compared with the formed developing sleeve.
Also, depending on the specific conditions of the iris-shaped groove, an abnormal image (like a horizontal black streak) appears at a predetermined pitch in the circumferential direction (rotation direction) of the developing sleeve and a portion having a high development density extending in the thrust direction. Hereinafter, it was found that a pitch-like horizontal black stripe was generated. Also, depending on the specific conditions of the iris-shaped groove, an abnormal image (like a horizontal black streak) appears at a predetermined pitch in the circumferential direction (rotation direction) of the developing sleeve and a portion having a high development density extending in the thrust direction. Hereinafter, it was found that a pitch-like horizontal black stripe was generated.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a developer carrier capable of suppressing a decrease in developer conveyance amount over time while having an iris-like groove, and a developer carrier. A developing device, a process cartridge including the developing device, and an image forming apparatus are provided.
Another object is to further provide a developer carrier capable of suppressing the occurrence of the pitch-like horizontal black stripes and the pitch-like horizontal black stripes, a developing device provided with the developer carrier, a process cartridge provided with the developing device, and An image forming apparatus is provided.

上記目的を達成するために、請求項1の発明は、回転スラスト方向に対して傾斜した方向に延びる複数の溝と、スラスト方向に対して反対側に傾斜した方向に延びる複数の溝とが交差するように形成されてなるアヤメ状の溝を有し、潜像担持体との対向部で互いの表面が同じ向きに移動するように回転させて使用される現像剤担持体において、何れの複数の溝も、スラスト方向に対する傾斜角度が、0度より大きく、かつ40度以下の範囲内である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の現像剤担持体において、前記あやめ状の溝のスラスト方向における溝交点間距離が、1.3mm以上かつ4.8mm以下の範囲内になるように上記傾斜角を設定したに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の現像剤担持体において、前記あやめ状の溝の周方向における溝交点間距離a(単位mm)が、次式の下限以上かつ上限以下の範囲内になるように上記傾斜角を設定したことを特徴とするものである。
(下限)=0.38×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
(上限)=1.1×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
また、請求項4の発明は、請求項1〜3の何れ一の現像剤担持体と、トナー粒子と磁性粒子からなる2成分現像剤を収容する現像容器と、該現像容器内に収容された2成分現像剤を攪拌しつつ搬送する現像剤搬送手段と、現像剤担持体上の現像剤の量を一定量に規制する現像剤規制手段とを有する現像装置。
また、請求項5の発明は、請求項4の現像装置と、感光体、帯電手段及びクリーニング手段より選ばれる少なくとも1つの手段とを一体に支持し、画像形成装置本体に着脱自在であるプロセスカートリッジ。
また、請求項6の発明は、請求項5のプロセスカートリッジを備えた画像形成装置。
また、請求項7の発明は、請求項5のプロセスカートリッジを複数個備えたカラー画像形成装置。
また、請求項8の発明は、請求項6又は7の画像形成装置において、前記現像手段で用いられるトナーは、体積平均粒径が3〜8μmで、体積平均粒径(Dv)と個数平均粒径(Dn)との比(Dv/Dn)が1.00〜1.40の範囲にある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6又は7に記載の画像形成装置において、前記現像手段で用いられるトナーは、形状係数SF−1が100〜180の範囲にあり、形状係数SF−2が100〜180の範囲にあることを特徴とするものである。
In order to achieve the above object, according to the first aspect of the present invention, the plurality of grooves extending in the direction inclined with respect to the rotational thrust direction intersect with the plurality of grooves extending in the direction inclined opposite to the thrust direction. In the developer carrier having an iris-shaped groove formed so as to be rotated so that the surfaces thereof move in the same direction at the portion facing the latent image carrier, The groove is also characterized in that the inclination angle with respect to the thrust direction is larger than 0 degree and within a range of 40 degrees or less.
According to a second aspect of the present invention, in the developer carrying member of the first aspect, the distance between the groove intersections in the thrust direction of the iris-shaped groove is in the range of 1.3 mm or more and 4.8 mm or less. The inclination angle is set.
According to a third aspect of the present invention, in the developer carrying member of the first or second aspect, a distance a (unit: mm) between groove intersections in the circumferential direction of the iris-shaped groove is not less than the lower limit and not more than the upper limit of the following formula: The inclination angle is set so as to be within the range.
(Lower limit) = 0.38 × (Linear velocity on developer carrier surface) / (Linear velocity on latent image carrier surface)
(Upper limit) = 1.1 × (Linear speed on developer carrier surface) / (Linear speed on latent image carrier surface)
According to a fourth aspect of the invention, there is provided the developer carrying member according to any one of the first to third aspects, a developing container containing a two-component developer comprising toner particles and magnetic particles, and the developing container accommodated in the developing container. A developing device comprising developer conveying means for conveying a two-component developer while stirring, and developer regulating means for regulating the amount of developer on the developer carrying member to a constant amount.
According to a fifth aspect of the present invention, there is provided a process cartridge which integrally supports the developing device of the fourth aspect and at least one means selected from a photosensitive member, a charging means and a cleaning means, and is detachable from the main body of the image forming apparatus. .
The invention of claim 6 is an image forming apparatus comprising the process cartridge of claim 5.
The invention of claim 7 is a color image forming apparatus comprising a plurality of process cartridges of claim 5.
According to an eighth aspect of the present invention, in the image forming apparatus of the sixth or seventh aspect, the toner used in the developing unit has a volume average particle diameter of 3 to 8 μm, a volume average particle diameter (Dv) and a number average particle diameter. The ratio (Dv / Dn) to the diameter (Dn) is in the range of 1.00 to 1.40.
The invention according to claim 9 is the image forming apparatus according to claim 6 or 7, wherein the toner used in the developing unit has a shape factor SF-1 in the range of 100 to 180, and the shape factor SF-2. Is in the range of 100-180.

請求項1乃至9の発明によれば、経時の現像剤搬送量低下を抑制できる。
特に、請求項2の発明によれば、ピッチ状縦黒スジの発生を抑制できるという効果がある。
また、請求項3の発明によれば、ピッチ状横黒スジの発生を抑制できるという効果がある。
According to the first to ninth aspects of the present invention, it is possible to suppress a decrease in developer transport amount over time.
In particular, according to the invention of claim 2, there is an effect that generation of pitch-like vertical black stripes can be suppressed.
According to the invention of claim 3, there is an effect that the generation of pitch-like horizontal black stripes can be suppressed.

以下、本発明の実施形態に係る画像形成装置の一例を説明する。図1はその作像部分の概略構成図である。この画像形成装置はいわゆるタンデム型のカラー複写機で、中間転写ベルト5を備えるタイプである。この中間転写ベルト5の展張部に対向するように複数の感光体1a〜dが配設されている。帯電手段である帯電ローラ2a〜dによって均一に帯電された感光体1a〜dに対し書込位置3a〜dで書込手段3による書き込みがされて光学的に潜像が形成される。この潜像が現像手段4a〜dで現像されトナーからなる可視像が形成される。各感光体1a〜dに形成されたトナー像は中間転写ベルト転写手段12a〜dによって中間転写ベルト5に順次重ね合わせて転写される。中間転写ベルト5のトナー像は、レジストローラ対6を経て搬送された転写紙に紙転写手段である紙転写ベルト7によって転写紙に転写される。転写紙に転写されたトナー像は紙転写ベルト7により定着手段8に搬送され転写紙上に熱により定着される。トナー像が定着された転写は図示しない排紙トレイなどに上に排出される。感光体1a〜d上の中間転写ベルト5に転写されなかった未転写トナーは感光体クリーニングブレード9a〜dによって感光体上から掻き落とされる。感光体は、感光体上の残留電荷が図示しない除電手段により除電され、次の作像動作に備える。感光体クリーニングブレード9a〜dによって掻き落とされた未転写トナーは回収トナー搬送経路14a〜dを通って廃トナー収容容器15に収容される。また中間転写ベルト上の未転写トナーやプロセスコントロール用のパターン像は中間転写クリーニングブレード13によって中間転写ベルト5上から掻き落とされ、同じく回収トナー搬送経路14eを通って廃トナー収容容器15に収容される。   Hereinafter, an example of an image forming apparatus according to an embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of the image forming portion. This image forming apparatus is a so-called tandem type color copier and is of a type provided with an intermediate transfer belt 5. A plurality of photoconductors 1 a to 1 d are arranged so as to face the extended portion of the intermediate transfer belt 5. Writing is performed by the writing unit 3 at the writing positions 3a to d on the photoconductors 1a to d uniformly charged by the charging rollers 2a to d which are charging units, and a latent image is optically formed. The latent image is developed by the developing means 4a to 4d to form a visible image made of toner. The toner images formed on the photoreceptors 1a to 1d are sequentially transferred onto the intermediate transfer belt 5 by the intermediate transfer belt transfer units 12a to 12d. The toner image on the intermediate transfer belt 5 is transferred onto the transfer paper by the paper transfer belt 7 serving as a paper transfer means onto the transfer paper conveyed through the resist roller pair 6. The toner image transferred onto the transfer paper is conveyed to the fixing means 8 by the paper transfer belt 7 and fixed on the transfer paper by heat. The transfer on which the toner image is fixed is discharged upward to a paper discharge tray (not shown). Untransferred toner that has not been transferred to the intermediate transfer belt 5 on the photoreceptors 1a to 1d is scraped off from the photoreceptor by the photoreceptor cleaning blades 9a to 9d. The remaining charge on the photoreceptor is neutralized by a neutralizing unit (not shown) to prepare for the next image forming operation. The untransferred toner scraped off by the photoconductor cleaning blades 9a to 9d is accommodated in the waste toner container 15 through the collected toner conveyance paths 14a to 14d. Further, the untransferred toner on the intermediate transfer belt and the pattern image for process control are scraped off from the intermediate transfer belt 5 by the intermediate transfer cleaning blade 13, and are also stored in the waste toner storage container 15 through the recovered toner transport path 14e. The

上記現像装置4a〜dへはニュートナーが補給される。トナーボトルに充填されたニュートナーがトナー補給装置10a〜dにより機械本体の後側のトナーホッパ部11a〜dへ補給される。現像装置内のトナー濃度検知手段(図2の符号21)により現像装置内のトナー濃度が低いと判断された場合、トナーホッパ内のトナー補給スクリュを(図示せず)を回転させ、適量のトナーをトナーホッパ内から現像装置へ供給する。トナーボトルのトナー残量検知はトナーホッパ内にトナー有り無しセンサ(図示せず)を用いて行う。具体的には、このセンサがトナー無しを検知した場合にトナー補給装置10a〜dにトナーの供給を要求する。そして所定時間要求してもトナー有りを検知しなかった場合にトナー無しと判断する。   New toner is supplied to the developing devices 4a to 4d. The new toner filled in the toner bottle is supplied to the toner hoppers 11a to 11d on the rear side of the machine body by the toner supply devices 10a to 10d. When the toner concentration detection means (reference numeral 21 in FIG. 2) in the developing device determines that the toner concentration in the developing device is low, the toner replenishing screw (not shown) in the toner hopper is rotated to supply an appropriate amount of toner. The toner is supplied from the toner hopper to the developing device. The toner remaining amount in the toner bottle is detected using a toner presence / absence sensor (not shown) in the toner hopper. Specifically, when this sensor detects the absence of toner, the toner supply devices 10a to 10d are requested to supply toner. If the presence of toner is not detected even if requested for a predetermined time, it is determined that there is no toner.

図2は1つの感光体についての作像部の拡大図である。何れの感光体についても同様の構成であるので、この図2では符号の添え字a〜dは省略している。この画像形成装置では、感光体1と、現像部4、帯電手段である帯電ローラ2、及びクリーニング手段であるクリーニングブレード9とを一体としたプロセスカートリッジになっている。装置本体に対してこのプロセスカートリッジが脱着可能である。現像装置4は感光体にトナーを供給する現像ローラ16を有する。その現像ローラ16が感光体1に対向する現像領域の上流側で現像ローラ16上の現像剤量をある一定量に規制する規制部材としての現像ドクタ17も有する。現像装置内の現像タンク部にはトナー粒子と磁性粒子(キャリア)を混合した2成分現像剤が納められており、その現像剤は第1搬送スクリュ18と第2搬送スクリュ19の2本の搬送スクリュで循環されるようになっている。この第2搬送スクリュ19の下側にトナー濃度センサ21が配置され、現像タンク内のトナー濃度を随時計測し、適正値に収まるよう制御している。トナー補給部からのトナーは一旦サブホッパ部(図示せず)に蓄えられ、現像タンク内のトナー濃度の値がトナー濃度センサにより低いと検知されたとき、所定の換算式により換算された時間だけトナー補給スクリュ22を回転させ適切な量のトナーを現像トナー供給口23へ補給する。また、現像ドクタ17の図中右側には現像ニップ部からのトナー飛散を防止するための入口シール20が配置されている。上記現像ドクタ17は非磁性部材にて構成されている現像ドクタ母体と磁性部材により構成されている現像ドクタ補助24の2部品により構成されている。現像ドクタ母体は現像ローラ上の現像剤量をある一定量に規制する役割をもち、かつ現像剤を規制する際に現像剤圧をこのドクタにて受けることになるので、非磁性部材である程度の厚さ(約1.5〜2mm)と先端部0.05mm程度の真直性を要求されるのが一般的である。現像ドクタ補助24は現像領域に搬送されるトナーの帯電を補う役割をもち、通常現像ドクタ母体よりかなり薄い板金(0.2mm程度)にて構成されている。この2部品の位置関係はトナー帯電性を長手方向にて均一にするため、精度良く維持される必要性があるので、スポット溶接やカシメ等により一体化し現像ローラ上からの距離が一定になるようにしている。また、図示の例では現像ローラ中心に対し現像ドクタが下方にある。   FIG. 2 is an enlarged view of an image forming unit for one photoconductor. Since all the photoconductors have the same configuration, the suffixes a to d are omitted in FIG. In this image forming apparatus, a photosensitive cartridge 1, a developing unit 4, a charging roller 2 as a charging unit, and a cleaning blade 9 as a cleaning unit are integrated into a process cartridge. The process cartridge can be attached to and detached from the apparatus main body. The developing device 4 includes a developing roller 16 that supplies toner to the photoreceptor. The developing roller 16 also has a developing doctor 17 as a regulating member that regulates the amount of developer on the developing roller 16 to a certain fixed amount upstream of the developing region where the developing roller 16 faces the photoreceptor 1. A two-component developer in which toner particles and magnetic particles (carriers) are mixed is stored in a developing tank portion in the developing device, and the developer is transported by two transports of a first transport screw 18 and a second transport screw 19. It is designed to be circulated with a screw. A toner concentration sensor 21 is disposed below the second conveying screw 19, and the toner concentration in the developing tank is measured at any time and controlled so as to be within an appropriate value. The toner from the toner replenishing unit is temporarily stored in a sub hopper unit (not shown), and when the toner concentration value in the developing tank is detected to be low by the toner concentration sensor, the toner is supplied for the time converted by a predetermined conversion formula. The supply screw 22 is rotated to supply an appropriate amount of toner to the developing toner supply port 23. An inlet seal 20 for preventing toner scattering from the developing nip portion is disposed on the right side of the developing doctor 17 in the drawing. The developing doctor 17 is composed of two parts: a developing doctor base composed of a non-magnetic member and a developing doctor auxiliary 24 composed of a magnetic member. The development doctor base has a role of regulating the amount of developer on the developing roller to a certain amount, and the developer pressure is received by this doctor when regulating the developer. In general, thickness (about 1.5 to 2 mm) and straightness of about 0.05 mm at the tip are required. The developing doctor auxiliary 24 has a role of supplementing the charging of the toner conveyed to the developing area, and is usually constituted by a sheet metal (about 0.2 mm) that is considerably thinner than the developing doctor base. The positional relationship between the two parts needs to be maintained with high accuracy in order to make the toner charging property uniform in the longitudinal direction, so that the distance from the developing roller is made constant by integration by spot welding or caulking. I have to. In the illustrated example, the developing doctor is below the center of the developing roller.

図3は現像装置4全体の斜視図である。現像装置4の上ケース28にはこのユニットの出荷時に現像剤を入れるプリセットスペース28’がある。これはユニットとして輸送時にこの部分に現像剤を入れ、除去可能なシール部材によりシールさせることで、着荷時にこのシールをひき、使用可能な状態にさせるもので、輸送時の剤漏れ防止の為の機構である。図4は上ケース28(図3参照)を外した状態の現像装置の斜視図である。現像ローラ16、第1搬送スクリュ18、第2搬送スクリュ19が見える状態になっており、これらの搬送スクリュにより第1現像剤溜まりと第2現像剤溜まりの間で現像剤を循環している。   FIG. 3 is a perspective view of the entire developing device 4. The upper case 28 of the developing device 4 has a preset space 28 'in which a developer is placed when the unit is shipped. This is because the developer is put into this part during transportation as a unit and sealed with a removable seal member, and this seal is pulled when it arrives, so that it can be used. Mechanism. FIG. 4 is a perspective view of the developing device with the upper case 28 (see FIG. 3) removed. The developing roller 16, the first conveying screw 18, and the second conveying screw 19 are visible, and the developer is circulated between the first developer reservoir and the second developer reservoir by these conveying screws.

図5は現像装置の一部の分解斜視図である。現像ローラ16は、内部に固定されているマグネット部25とこのマグネット部25の内蔵し現像剤を搬送するため回転可能な現像スリーブ部26にて構成されている。内部の固定マグネット部25は作像領域のやや外側まで存在し、転写紙の搬送バラツキを考慮したマグネット長さの位置関係になっている。外側の現像スリーブ26は、通常アルミ材により構成され、現像剤を搬送しやすくするために、あやめ状の溝を設けている。このあやめ状の溝については後に詳述する。上記現像ドクタ17は非磁性部材にて構成されている現像ドクタ母体17’と磁性部材により構成されている現像ドクタ補助24の2部品により構成されている。現像ドクタ母体17’を現像ケーシング27に固定することにより、現像ローラ16に対して所定の間隔を開けて対向する構成となっている。現像ドクタ母体17’は現像ローラ上の現像剤量をある一定量に規制する役割をもち、かつ現像剤を規制する際に現像剤圧をこのドクタにて受けることになるので、非磁性部材である程度の厚さ(約1.5〜2mm)と先端部0.05mm程度の真直性を要求されるのが一般的である。現像ドクタ補助24は現像領域に搬送されるトナーの帯電を補う役割をもち、通常現像ドクタ母体よりかなり薄い板金(0.2mm程度)にて構成されている。この2部品の位置関係はトナー帯電性を長手方向にて均一にするため、精度良く維持される必要性があるので、スポット溶接やカシメ等により一体化し現像ローラ上からの距離が一定になるようにしている。また、図示の例では現像ローラ中心に対し現像ドクタが下方にある。現像ケーシング27には、第1搬送スクリュ18と第2搬送スクリュ19が軸受(図示せず)を介し組み込まれる。現像ケーシング27の前後の側板の内側には、現像ローラ端部からの現像剤飛散を抑えるための磁性板28が取り付けられている。   FIG. 5 is an exploded perspective view of a part of the developing device. The developing roller 16 includes a magnet portion 25 fixed inside and a developing sleeve portion 26 that is built in the magnet portion 25 and is rotatable to convey the developer. The internal fixed magnet portion 25 exists slightly outside the image forming area, and has a magnet length positional relationship in consideration of transfer paper transfer variation. The outer developing sleeve 26 is usually made of an aluminum material, and is provided with an iris-like groove to facilitate transport of the developer. This iris-shaped groove will be described in detail later. The developing doctor 17 is composed of two parts, a developing doctor base 17 'made of a nonmagnetic member and a developing doctor auxiliary 24 made of a magnetic member. By fixing the developing doctor base 17 ′ to the developing casing 27, the developing doctor base 17 ′ is opposed to the developing roller 16 with a predetermined gap. The developing doctor base 17 ′ has a role of regulating the amount of developer on the developing roller to a certain fixed amount, and receives the developer pressure at the doctor when regulating the developer. Generally, a certain degree of thickness (about 1.5 to 2 mm) and straightness of about 0.05 mm at the tip are required. The developing doctor auxiliary 24 has a role of supplementing the charging of the toner conveyed to the developing area, and is usually constituted by a sheet metal (about 0.2 mm) that is considerably thinner than the developing doctor base. The positional relationship between the two parts needs to be maintained with high accuracy in order to make the toner charging property uniform in the longitudinal direction, so that the distance from the developing roller is made constant by integration by spot welding or caulking. I have to. In the illustrated example, the developing doctor is below the center of the developing roller. A first conveying screw 18 and a second conveying screw 19 are incorporated into the developing casing 27 via bearings (not shown). On the inner side of the front and rear side plates of the developing casing 27, a magnetic plate 28 is attached to suppress the developer scattering from the end of the developing roller.

次に、以上の画像形成装置に好適に使用されるトナーについて説明する。
600dpi以上の微少ドットを再現するために、トナーの体積平均粒径は3〜8μmが好ましい。体積平均粒径(Dv)と個数平均粒径(Dn)との比(Dv/Dn)は1.00〜1.40の範囲にあることが好ましい。(Dv/Dn)が1.00に近いほど粒径分布がシャープであることを示す。このような小粒径で粒径分布の狭いトナーでは、トナーの帯電量分布が均一になり、地肌かぶりの少ない高品位な画像を得ることができ、また、静電転写方式では転写率を高くすることができる。
Next, a toner suitably used in the above image forming apparatus will be described.
In order to reproduce minute dots of 600 dpi or more, the toner preferably has a volume average particle diameter of 3 to 8 μm. The ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. With such a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution is uniform, a high-quality image with little background fogging can be obtained, and the electrostatic transfer method has a high transfer rate. can do.

トナーの形状係数SF−1は100〜180、形状係数SF−2は100〜180の範囲にあることが好ましい。図6は形状係数SF−1を、図7は形状係数SF−2をそれぞれ説明するためにトナーの形状を模式的に表した図である。形状係数SF−1は、トナー形状の丸さの割合を示すものであり、下記式(1)で表される。トナーを2次元平面に投影してできる形状の最大長MXLNGの二乗を図形面積AREAで除して、100π/4を乗じた値である。
SF−1={(MXLNG)/AREA}×(100π/4)・・・式(1)
SF−1の値が100の場合トナーの形状は真球となり、SF−1の値が大きくなるほど不定形になる。また、形状係数SF−2は、トナー形状の凹凸の割合を示すものであり、下記式(2)で表される。トナーを2次元平面に投影してできる図形の周長PERIの二乗を図形面積AREAで除して、100π/4を乗じた値である。
SF−2={(PERI)/AREA}×(100π/4)・・・式(2)
SF−2の値が100の場合トナー表面に凹凸が存在しなくなり、SF−2の値が大きくなるほどトナー表面の凹凸が顕著になる。形状係数の測定は、具体的には、走査型電子顕微鏡(S−800:日立製作所製)でトナーの写真を撮り、これを画像解析装置(LUSEX3:ニレコ社製)に導入して解析して計算した。トナーの形状が球形に近くなると、トナーとトナーあるいはトナーと感光体との接触状態が点接触になるために、トナー同士の吸着力は弱くなり従って流動性が高くなり、また、トナーと感光体との吸着力も弱くなって、転写率は高くなる。形状係数SF−1、SF−2のいずれかが180を超えると、転写率が低下するため好ましくない。
The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. FIG. 6 is a diagram schematically illustrating the shape of the toner in order to explain the shape factor SF-1, and FIG. 7 is a diagram illustrating the shape factor SF-2. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) 2 / AREA} × (100π / 4) (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases. The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) 2 / AREA} × (100π / 4) Expression (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent. Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated. When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

本発明の現像担持体として現像ローラについて説明する。図8は現像スリーブ26の斜視図、図9は現像スリーブ26表面の拡大図である。本発明の現像ローラ表面(現像スリーブ表面)上にはあやめ状の溝を形成している。あやめ状の溝とは、現像ローラ回転軸方向(スラスト方向)に対して傾斜した複数の溝と、スラスト方向に対して反対側に傾斜した複数の溝とが交差するように形成されるものである。前者の複数の溝における傾斜の角度と、後者の複数の溝における傾斜の角度とは、必ずしも互いに同一でなくてもよい。このようなあやめ溝形状のスリーブによれば、現像剤が現像剤量をある一定量に規制する現像ドクタ17を通過する際に、搬送溝が斜めでストレスを受けることがなくなるので、現像剤寿命を延ばすことが出来ると共に、剤搬送溝が斜めのためドクタ通過時の衝撃が緩和できショックジターも改善される。   A developing roller will be described as the developing carrier of the present invention. FIG. 8 is a perspective view of the developing sleeve 26, and FIG. 9 is an enlarged view of the surface of the developing sleeve 26. An iris-like groove is formed on the surface of the developing roller (the surface of the developing sleeve) of the present invention. The iris-shaped groove is formed such that a plurality of grooves inclined with respect to the developing roller rotation axis direction (thrust direction) and a plurality of grooves inclined opposite to the thrust direction intersect. is there. The angle of inclination in the former plurality of grooves and the angle of inclination in the latter plurality of grooves are not necessarily the same. According to such an iris groove-shaped sleeve, when the developer passes through the developing doctor 17 that regulates the developer amount to a certain amount, the conveying groove is not inclined and stressed, so that the developer life is shortened. In addition, since the agent conveying groove is slanted, the impact when passing through the doctor can be mitigated and the shock jitter can be improved.

図9中、符号aはで示すのはあやめ溝のスラスト方向における交点間距離、符号bはで示すのはあやめ溝の周方向における交点間距離、符号cで示すのは外径である。本実施形態に係る現像スリーブは、何れの複数の溝も、スラスト方向に対する傾斜角度が、0度より大きく、かつ40度以下の範囲内である。好ましくは、5度以上である。そして、更に、スラスト方向の交点間距離aが1.3mm以上かつ4.8mm以下の範囲内になるように上記傾斜角を設定することが好ましい。また、更に、周方向の交点間距離b(単位mm)が次式の下限以上かつ上限以下の範囲内になるように上記傾斜角を設定することが好ましい。
(下限)=0.38×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
(上限)=1.1×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
In FIG. 9, the symbol a indicates the distance between the intersections in the thrust direction of the iris groove, the symbol b indicates the distance between the intersections in the circumferential direction of the iris groove, and the symbol c indicates the outer diameter. In the developing sleeve according to the present embodiment, any of the plurality of grooves has an inclination angle with respect to the thrust direction in the range of greater than 0 degrees and 40 degrees or less. Preferably, it is 5 degrees or more. Further, it is preferable to set the inclination angle so that the distance a between the intersections in the thrust direction is within a range of 1.3 mm or more and 4.8 mm or less. Furthermore, it is preferable to set the inclination angle so that the distance b (unit: mm) between the intersections in the circumferential direction is within the range of the lower limit and the upper limit of the following formula.
(Lower limit) = 0.38 × (Linear velocity on developer carrier surface) / (Linear velocity on latent image carrier surface)
(Upper limit) = 1.1 × (Linear speed on developer carrier surface) / (Linear speed on latent image carrier surface)

まず、何れの複数の溝も、スラスト方向に対する傾斜角度が、0度より大きく、かつ40度以下の範囲内にすることの意義について説明する。
図10は横軸のプリント枚数を取り、縦軸に現像剤ドクタ通過後の現像スリーブ単位面積当たりの現像剤保持量を取って、2種名の現像スリーブについて現像剤保持量の経時変化を示すグラフである。現像剤保持量の適正量は40mg/mm〜56mg/mmである。下限より少ないと現像濃度が足りず、上限より多いと、ドクタ部での現像剤への過剰なストレスなどを不具合が生じる。図10中、比較的現像剤保持量が多い現像スリーブは、耐久予定枚数(このグラフで示す横軸の範囲。例えば16万枚)まで、必要最小量を下回ることなく使用できたが、比較的現像剤保持量が少ない現像スリーブは、耐久予定枚数に達する前に必要最小量を下回ってしまっている。このように現像剤保持量が経時で低下する定価具合が、上記傾斜角度に関係していることを見いだした。具体的には、傾斜角度が大きくなるほど経時での低下度合いがおおく、40度を超えると、通常現像スリーブに要求されることが多い、十数万枚の耐久予定枚数を保障するのが困難であることがわかった。表1は各種の溝断面形状及び溝傾斜角度について実験した結果を示すものである。表中の「アヤメ角度」が上記傾斜角度を示す。○は当初から16万枚まで適正範囲の現像剤保持量を確保できたことを示し、×は適正範囲の下限を経時で下回ったことを示す。
First, the significance of making any of the plurality of grooves have an inclination angle with respect to the thrust direction larger than 0 degree and not more than 40 degrees will be described.
FIG. 10 shows the change over time in the developer holding amount of the two types of developing sleeves, taking the number of prints on the horizontal axis and the developer holding amount per unit area of the developing sleeve after passing the developer doctor on the vertical axis. It is a graph. Proper amount of the developer holding amount is 40mg / mm 2 ~56mg / mm 2 . If it is less than the lower limit, the development density is insufficient, and if it exceeds the upper limit, problems such as excessive stress on the developer in the doctor section occur. In FIG. 10, the developing sleeve having a relatively large amount of developer can be used up to the planned endurance number (the range of the horizontal axis shown in this graph. For example, 160,000 sheets) without lowering the required minimum amount. The developing sleeve having a small developer holding amount has fallen below the minimum required amount before reaching the expected durability. Thus, it has been found that the fixed price at which the developer holding amount decreases with time is related to the inclination angle. Specifically, the degree of decrease with time increases as the tilt angle increases. If it exceeds 40 degrees, it is difficult to guarantee the expected number of endurances of several hundred thousand, which is usually required for a developing sleeve. I found out. Table 1 shows the results of experiments on various groove cross-sectional shapes and groove inclination angles. “Iris angle” in the table indicates the inclination angle. ○ indicates that the developer holding amount in the proper range could be secured from the beginning to 160,000 sheets, and x indicates that the lower limit of the proper range was exceeded over time.

次に、スラスト方向の交点間距離aが1.3mm以上かつ4.8mm以下の範囲内になるように上記傾斜角を設定することの意義について説明する。スラスト方向の交点間距離について下限を1.3mmとしたのは次の理由による。すなわち、最近は高画質化のために現像ローラと感光体1とのギャップは1mm以下に設定されているが一般的である。このように現像ギャップを狭く設定するのに応じて現像ローラ表面での単位面積当たりの現像剤保持量(搬送量)も少なくてすむようになってきている。例えば40mg/cmである。上記交点間距離mの設定が狭いほど溝の本数が多くなり現像剤保持量が多くなるが、以上のように最近の現像ギャップに応じた現像剤保持量を確保するには交点間距離mが1.3mmに対応する本数あれば十分である。これより交点間距離mを狭くして本数を多くしても、溝加工の時間がながくかかったり、加工時に現像スリーブにかかるストレスが増大してひずみを生じたりするといった不具合がでる。よって、下限を1.3mmに設定した。上限を4.8mmに設定したのは次の理由による。上記交点間距離mが4.8mm超の場合、縦黒スジ画像が発生する。溝でない表面部分に比して溝では剤搬送が多いため溝部に現像剤は溜まっている。あやめ溝の場合、溝が交差しているため溝交点部分とそれ以外の溝部分では汲み上げ量に差が生じ、交点部分の方が多い。この結果、溝の交点部分とそれ以外の部分とで現像濃度差が生じる。実際に画像で顕著になるには濃い部分の間隔が広くならないと顕著にならない。すなわち、人の目にはめだたない。評価した結果では4.8mmを超えると縦黒スジのムラとなって顕在化する。よって、上限を4.8mmに設定した。 Next, the significance of setting the tilt angle so that the distance a between the intersections in the thrust direction is within a range of 1.3 mm or more and 4.8 mm or less will be described. The reason why the lower limit of the distance between the intersections in the thrust direction is 1.3 mm is as follows. That is, in recent years, the gap between the developing roller and the photosensitive member 1 is generally set to 1 mm or less in order to improve image quality. In this way, as the development gap is set narrower, the developer holding amount (conveyance amount) per unit area on the surface of the developing roller can be reduced. For example, 40 mg / cm 2 . The narrower the setting of the distance between the intersections m, the more the number of grooves and the larger the developer holding amount. However, as described above, in order to secure the developer holding amount according to the recent development gap, A number corresponding to 1.3 mm is sufficient. Even if the distance m between the intersections is made narrower and the number is increased, there are problems that it takes a long time for the grooving process, or stress is applied to the developing sleeve during the process and distortion occurs. Therefore, the lower limit was set to 1.3 mm. The upper limit is set to 4.8 mm for the following reason. When the distance m between the intersections exceeds 4.8 mm, a vertical black streak image is generated. Since the amount of the agent transported in the groove is larger than that in the surface portion that is not the groove, the developer is accumulated in the groove portion. In the case of the iris groove, since the grooves intersect, there is a difference in the pumping amount between the groove intersection portion and the other groove portions, and there are more intersection points. As a result, a development density difference occurs between the intersection of the grooves and the other portion. In order to actually become prominent in an image, it does not become prominent unless the interval between dark portions becomes wide. In other words, it is inconspicuous. As a result of the evaluation, if the thickness exceeds 4.8 mm, vertical black streaks appear and become apparent. Therefore, the upper limit was set to 4.8 mm.

次に、周方向の交点間距離b(単位mm)が次式の下限以上かつ上限以下の範囲内になるように上記傾斜角を設定することの意義について説明する。
(下限)=0.38×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
(上限)=1.1×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
Next, the significance of setting the tilt angle so that the distance b (unit: mm) between the intersections in the circumferential direction is within the range between the lower limit and the upper limit of the following equation will be described.
(Lower limit) = 0.38 × (Linear velocity on developer carrier surface) / (Linear velocity on latent image carrier surface)
(Upper limit) = 1.1 × (Linear speed on developer carrier surface) / (Linear speed on latent image carrier surface)

下限は次の理由から設定した。すなわち、上述のように、最近は高画質化のために現像ローラと感光体1とのギャップは1mm以下に設定されているが一般的である。このように現像ギャップを狭く設定するのに応じて現像ローラ表面での単位面積当たりの現像剤保持量(搬送量)も少なくてすむようになってきている。この現像剤保持量は感光体1と現像スリーブ26との対向部で線速関係にも左右される。また、溝の本数が多くなるほど現像剤保持量が多くなる。以上のように最近の現像ギャップに応じた現像剤保持量を確保するには上記下限以上であれば、十分であることが確認された。これより交点間距離mが狭くなるように溝の本数を多くしても、溝加工の時間がながくかかったり、加工時に現像スリーブにかかるストレスが増大してひずみを生じたりするといった不具合がでる。よって、下限を上記のように設定した。   The lower limit was set for the following reason. That is, as described above, recently, the gap between the developing roller and the photoreceptor 1 is generally set to 1 mm or less in order to improve the image quality. In this way, as the development gap is set narrower, the developer holding amount (conveyance amount) per unit area on the surface of the developing roller can be reduced. This developer holding amount depends on the linear velocity relationship at the facing portion between the photosensitive member 1 and the developing sleeve 26. Further, the developer holding amount increases as the number of grooves increases. As described above, it has been confirmed that the above-mentioned lower limit is sufficient to secure the developer holding amount corresponding to the recent development gap. Even if the number of grooves is increased so that the distance m between the intersections becomes narrower than this, there is a problem that it takes a long time for the grooving or the stress applied to the developing sleeve during the processing increases to cause distortion. Therefore, the lower limit was set as described above.

上限は次の理由から設定した。上記交点間距離aが上記上限を超える場合、ピッチ状横黒スジ画像が発生する。溝でない表面部分に比して溝では剤搬送が多いため溝部に現像剤は溜まっている。あやめ溝の場合、溝が交差しているため溝交点部分とそれ以外の溝部分では汲み上げ量に差が生じ、交点部分の方が多い。この結果、溝の交点部分とそれ以外の部分とで現像濃度差が生じる。実際に画像で顕著になるには濃い部分の間隔が広くならないと顕著にならない。すなわち、人の目にはめだたない。評価した結果では1.1mmを超えると横黒スジのムラとなって顕在化する。よって、感光体1と現像スリーブ26の線速比を考慮し、上限を上述のように設定した。   The upper limit was set for the following reasons. When the distance a between the intersections exceeds the upper limit, a pitch-like horizontal black streak image is generated. Since the amount of the agent transported in the groove is larger than that in the surface portion that is not the groove, the developer is accumulated in the groove portion. In the case of the iris groove, since the grooves intersect, there is a difference in the pumping amount between the groove intersection portion and the other groove portions, and there are more intersection points. As a result, a development density difference occurs between the intersection of the grooves and the other portion. In order to actually become prominent in an image, it does not become prominent unless the interval between dark portions becomes wide. In other words, it is inconspicuous. As a result of the evaluation, if the thickness exceeds 1.1 mm, horizontal black stripes appear and become apparent. Therefore, the upper limit is set as described above in consideration of the linear velocity ratio between the photosensitive member 1 and the developing sleeve 26.

なお、表1に示す各あやめ溝角度の現像スリーブのスラスト方向の交点間距離a、周方向の交点間距離bは次の表2のとおりです。この表2に示すようにスラスト方向の交点間距離aが上述の適正範囲にあるのは、角度25,35,40,45の例である。
表1に示す結果を示す実験の条件は、次のとおりである。
現像ローラの直径は18mm。
感光体1の線速150mm/秒、現像スリーブ26の線速290mm/秒。
溝は各傾斜方向40本で、合計80本。
ここで、周方向の交点間距離aは、18×π/40=1.41(mm)なる。この交点間距離aは、上述の下限(0.38×290/150=0.73・・)と上限(1.1×290/150=2.1・・)との間の範囲内になっている。
なお、周方向の交点間距離aとスライスと方向の交点間距離bと傾斜角度θとの間には一般に次式の関係が成立する。
tanθ=a/b
The following table 2 shows the distance a between the intersections in the thrust direction and the distance b between the intersections in the circumferential direction of each developing groove angle shown in Table 1. As shown in Table 2, the distance a between the intersections in the thrust direction is within the above-described appropriate range in the examples of the angles 25, 35, 40, and 45.
The experimental conditions showing the results shown in Table 1 are as follows.
The diameter of the developing roller is 18 mm.
The linear velocity of the photosensitive member 1 is 150 mm / second, and the linear velocity of the developing sleeve 26 is 290 mm / second.
There are 40 grooves in each tilt direction, for a total of 80 grooves.
Here, the distance a between the points in the circumferential direction is 18 × π / 40 = 1.41 (mm). The distance a between the intersections is in the range between the lower limit (0.38 × 290/150 = 0.73 ··) and the upper limit (1.1 × 290/150 = 2.1 ··). ing.
In general, the following relationship is established between the distance a between the intersections in the circumferential direction, the distance b between the slices in the direction of the slice, and the inclination angle θ.
tan θ = a / b

また、現像スリーブ26の外径をbは10mm以上かつ32mm以下の範囲内に設定することが好ましい。下限の理由は内部固定のマグネット部25のパターン磁力との関係による搬送性からの設定で、上限は加工上の実用性の観点からの設定である。例えば、感光体1の線速150mm/秒、現像スリーブ26の線速290mm/秒、上記交点ピッチが2.2mm(ほぼ前述の上限値に相当)とした場合、外径が10mmでは、交点数は14点となりその角度は中心よりピッチ約25度となる。これでは、内部固定マグネットのパターン磁力の半値角度の半分以上となり搬送性に問題が生じる。また外径32mmとすると、0.75mmピッチでは交点数134点と多点となり加工上困難になる事が確認された。   The outer diameter of the developing sleeve 26 is preferably set within the range of 10 mm to 32 mm. The reason for the lower limit is setting from the transportability due to the relationship with the pattern magnetic force of the internally fixed magnet portion 25, and the upper limit is setting from the viewpoint of practicality in processing. For example, when the linear velocity of the photosensitive member 1 is 150 mm / second, the linear velocity of the developing sleeve 26 is 290 mm / second, and the intersection pitch is 2.2 mm (corresponding to the above-described upper limit), the number of intersections is 10 mm. Is 14 points, and the angle is about 25 degrees from the center. This causes more than half of the half-value angle of the pattern magnetic force of the internal fixed magnet, causing a problem in transportability. Further, when the outer diameter is 32 mm, it is confirmed that the number of intersections is as many as 134 at a pitch of 0.75 mm, which makes it difficult to process.

現像ローラとして次の現像ローラをもちいて図1に示す画像形成装置で画像を形成したところ、ピッチ状横黒スジのムラが生じない良好な画像を形成できた。
現像ローラの直径は18mm。
感光体1の線速150mm/秒、現像スリーブ26の線速290mm/秒。
上記スラスト方向の交点間距離を1.3mm以上かつ4.8mm以下の範囲内の各種の現像スリーブを形成して実験した。
上記周方向の交点間距離0.75mm〜2.2mmの範囲内の各種の現像スリーブを形成して実験した。
表1に示す傾斜角度15度〜40度のものは16万枚まで、現像剤保持量の必要最小量を維持できた。
When the next developing roller was used as the developing roller and an image was formed by the image forming apparatus shown in FIG. 1, a good image in which unevenness of pitch-like horizontal black stripes did not occur was formed.
The diameter of the developing roller is 18 mm.
The linear velocity of the photosensitive member 1 is 150 mm / second, and the linear velocity of the developing sleeve 26 is 290 mm / second.
Experiments were conducted by forming various developing sleeves having a distance between intersections in the thrust direction of 1.3 mm or more and 4.8 mm or less.
Experiments were conducted by forming various developing sleeves having a distance of 0.75 mm to 2.2 mm between the intersections in the circumferential direction.
In Table 1, those having an inclination angle of 15 to 40 degrees were able to maintain the necessary minimum amount of developer holding amount up to 160,000 sheets.

以上、本実施の画像形成装置によれば、経時の現像剤搬送量低下を抑制できるとともに、あやめ状の溝のスラスト方向及び周方向それぞれにおける溝交点間距離が所定範囲内であるので、ピッチ状縦黒スジやピッチ状横黒スジの発生を抑制できる。
また、トナーとして、体積平均粒径が3〜8μmで、体積平均粒径(Dv)と個数平均粒径(Dn)との比(Dv/Dn)が1.00〜1.40の範囲にある粒径分布のものを使用すれば、さらに高画質な画像をえることができる。
また、トナーは、形状係数SF−1が100〜180の範囲にあり、形状係数SF−2が100〜180の範囲にあるものを使用すれば、さらに高画質な画像をえることができる。
As described above, according to the image forming apparatus of the present embodiment, it is possible to suppress a decrease in the developer conveyance amount with time, and the distance between the groove intersections in the thrust direction and the circumferential direction of the iris-shaped grooves is within a predetermined range. Generation of vertical black lines and pitch-shaped horizontal black lines can be suppressed.
The toner has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) in the range of 1.00 to 1.40. If one having a particle size distribution is used, a higher quality image can be obtained.
Further, if a toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180 is used, a higher quality image can be obtained.

本発明の実施形態に係るプリンタの概略構成図。1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. 上記プリンタのトナー像形成部を構成するプロセスカートリッジの概略構成図。FIG. 2 is a schematic configuration diagram of a process cartridge constituting a toner image forming unit of the printer. 現像装置の全体斜視図。1 is an overall perspective view of a developing device. 現像装置の内部構成をしめす斜視図。The perspective view which shows the internal structure of a developing device. 現像装置の一部の分解斜視図。FIG. 3 is an exploded perspective view of a part of the developing device. 形状係数SF−1を説明するためにトナー形状を模式的に表した説明図。FIG. 3 is an explanatory diagram schematically showing a toner shape for explaining a shape factor SF-1. 形状係数SF−2を説明するためにトナー形状を模式的に表した説明図。FIG. 4 is an explanatory diagram schematically showing a toner shape for explaining a shape factor SF-2. 現像スリーブの斜視図。The perspective view of a developing sleeve. 現像スリーブ表面の拡大図。The enlarged view of the surface of a developing sleeve. 測定結果を示すグラフ。The graph which shows a measurement result.

符号の説明Explanation of symbols

1 感光体
2 現像ローラ
1 Photoconductor 2 Developing roller

Claims (9)

  1. 回転スラスト方向に対して傾斜した方向に延びる複数の溝と、スラスト方向に対して反対側に傾斜した方向に延びる複数の溝とが交差するように形成されてなるアヤメ状の溝を有し、潜像担持体との対向部で互いの表面が同じ向きに移動するように回転させて使用される現像剤担持体において、
    何れの複数の溝も、スラスト方向に対する傾斜角度が、0度より大きく、かつ40度以下の範囲内であることを特徴とする現像剤担持体。
    A plurality of grooves extending in a direction inclined with respect to the rotational thrust direction and a plurality of grooves extending in a direction inclined in the opposite direction with respect to the thrust direction; In the developer carrier used by rotating so that the surfaces of each other move in the same direction at the portion facing the latent image carrier,
    The developer carrying member according to any one of the plurality of grooves, wherein an inclination angle with respect to the thrust direction is in a range of greater than 0 degrees and 40 degrees or less.
  2. 請求項1の現像剤担持体において、
    前記あやめ状の溝のスラスト方向における溝交点間距離が、1.3mm以上かつ4.8mm以下の範囲内になるように上記傾斜角を設定したにことを特徴とする現像剤担持体。
    The developer carrier of claim 1,
    The developer carrying member, wherein the inclination angle is set so that a distance between groove intersections in the thrust direction of the iris-shaped groove is within a range of 1.3 mm or more and 4.8 mm or less.
  3. 請求項1又は2の現像剤担持体において、
    前記あやめ状の溝の周方向における溝交点間距離a(単位mm)が、次式の下限以上かつ上限以下の範囲内になるように上記傾斜角を設定したことを特徴とする現像剤担持体。
    (下限)=0.38×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
    (上限)=1.1×(現像剤担持体表面の線速)/(潜像担持体表面の線速)
    In the developer carrier of claim 1 or 2,
    The developer carrying member, wherein the inclination angle is set so that the distance a (unit: mm) between the groove intersections in the circumferential direction of the iris-shaped groove is in the range of the lower limit and the upper limit of the following formula: .
    (Lower limit) = 0.38 × (Linear velocity on developer carrier surface) / (Linear velocity on latent image carrier surface)
    (Upper limit) = 1.1 × (Linear speed on developer carrier surface) / (Linear speed on latent image carrier surface)
  4. 請求項1〜3の何れ一の現像剤担持体と、トナー粒子と磁性粒子からなる2成分現像剤を収容する現像容器と、該現像容器内に収容された2成分現像剤を攪拌しつつ搬送する現像剤搬送手段と、現像剤担持体上の現像剤の量を一定量に規制する現像剤規制手段とを有する現像装置。   A developer carrying member according to any one of claims 1 to 3, a developer container containing a two-component developer composed of toner particles and magnetic particles, and conveying the two-component developer contained in the developer container while stirring. A developing device comprising: a developer transporting unit that controls the amount of the developer on the developer carrying member;
  5. 請求項4の現像装置と、感光体、帯電手段及びクリーニング手段より選ばれる少なくとも1つの手段とを一体に支持し、画像形成装置本体に着脱自在であるプロセスカートリッジ。   A process cartridge that integrally supports the developing device according to claim 4 and at least one unit selected from a photosensitive member, a charging unit, and a cleaning unit, and is detachable from an image forming apparatus main body.
  6. 請求項5のプロセスカートリッジを備えた画像形成装置。   An image forming apparatus comprising the process cartridge according to claim 5.
  7. 請求項5のプロセスカートリッジを複数個備えたカラー画像形成装置。   A color image forming apparatus comprising a plurality of process cartridges according to claim 5.
  8. 請求項6又は7の画像形成装置において、
    前記現像手段で用いられるトナーは、体積平均粒径が3〜8μmで、体積平均粒径(Dv)と個数平均粒径(Dn)との比(Dv/Dn)が1.00〜1.40の範囲にあることを特徴とする画像形成装置。
    The image forming apparatus according to claim 6 or 7,
    The toner used in the developing unit has a volume average particle diameter of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.00 to 1.40. An image forming apparatus characterized by being in the range.
  9. 請求項6又は7に記載の画像形成装置において、
    前記現像手段で用いられるトナーは、形状係数SF−1が100〜180の範囲にあり、形状係数SF−2が100〜180の範囲にあることを特徴とする画像形成装置。
    The image forming apparatus according to claim 6 or 7,
    The image forming apparatus according to claim 1, wherein the toner used in the developing unit has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180.
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JP2009003248A (en) * 2007-06-22 2009-01-08 Ricoh Co Ltd Developing sleeve, developing device, process cartridge, and image forming device
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JP2011145401A (en) 2010-01-13 2011-07-28 Ricoh Co Ltd Two-component developing method and developer used for the same
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