JP2004198752A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method and an image forming apparatus excellent in environmental stability and repetition stability, having good charging performance and transferring performance, and capable of simultaneously satisfying high image quality and high reliability. <P>SOLUTION: The image forming method comprises a charging step in which an electrostatic latent image carrier is charged by bringing a charging member into contact with the carrier and applying voltage from the outside, an electrostatic latent image forming step in which an electrostatic latent image is formed, and a toner image forming step in which the electrostatic latent image is converted to a clear image with an electrostatic charge image developer, wherein the electrostatic charge image developer comprises an electrostatic charge image developing toner which satisfies the following conditions (a)-(e). <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０２１４】
[静電荷像現像剤の製造]
得られたトナー粒子１〜１３各５０質量部に対し、疎水性シリカ（ＴＳ７２０：キャボット製）を０．５質量部添加し、サンプルミルにてブレンドした。
このブレンド物を、ポリメチルメタクリレート（総研化学社製）を１質量％コートした体積平均粒径が５０μｍのフエライトキャリアに対し、トナー濃度が５質量％になるように秤量し、ボールミルで５分間攪拌・混合し現像剤１〜１３を調製した。
【０２１５】
[帯電ロールの作製]
導電性支持体としてステンレス製のシャフト（直径：８ｍｍ、長さ：３５０ｍｍ）を用いて、その周囲に中抵抗の弾性体層を以下の配合及び加工方法により形成した。
【０２１６】
・ＧＥＣＯ系エピクロルヒドリン原料ゴム（エピクロマＣＧ１０２：ダイソー製、組成比：エピクロルヒドリン４０ｍｏｌ％、エチレンオキサイド５６ｍｏｌ％、アリルグリシジルエーテル４ｍｏｌ％）１００質量部
・炭酸カルシウム（タマパールＴＲ−２２２Ｈ：奥多摩工業製）３０質量部
・サブ（ネオファクチスＵ−８：天満サブ化工製） １０質量部
・テトラメチルアンモニウムクロライド（日本樹脂製：エレガンスＲ１１５）１．０質量部
・ステアリン酸（脂肪酸ＳＡ−２００：旭電化製）０．５質量部
・加硫促進剤（ノクセラＴＴ：大内新興化学製） １．０質量部
・加硫促進剤（ノクセラＤＭ：大内新興化学製） １．５質量部
・加硫促進剤（バルノックＲ：大内新興化学製） １．０質量部
・加硫剤（サルファックス：鶴見化学製） ０．２５質量部
【０２１７】
上記配合物を混練して均一な組成のコンパウンドとした後、上記ステンレス製シャフトの表面に、一次加硫（蒸気缶、４．５×１０²ｋＰａ、１５０℃×１時間）、２次加硫（１５５℃×７時間）によって、外径１４ｍｍ×長さ３１０ｍｍになるように成形して、ローラ状の中抵抗弾性体層を設けた。この中抵抗弾性体層の電気抵抗は２×１０⁷Ω・ｃｍ、ローラゴム硬度は３８度（ＪＩＳ Ａ）であった。
【０２１８】
次に、直鎖ポリエステル樹脂（バイロン３０ＳＳ：東洋紡（株）製）８０質量部、及びメラミン樹脂（スーパーベッカミンＧ−８２１−６０：大日本インキ（株）製）２０質量部に、導電性カーボン（ＦＷ２００：デグサ社製）５質量部、フッ素樹脂微粉（ルブロンＬ−５：ダイキン工業社製）１０質量部を混合し、サンドミルを用いて、混合分散させた。
【０２１９】
次いで、前記分散物をキシレンで希釈して（分散物１００質量部に対し、キシレン１５０質量部の割合）、表面層形成用塗料を調製し、粘度調整を行った。前記シャフトと弾性体層の端面とが接する部分から膜厚に相当する間隙を残してシャフトをマスキングした後、ベル型静電塗装機（ランズバーグインダストリー社製）を用い、前記中抵抗弾性体層の表面に乾燥時膜厚が３５μｍとなるように、弾性体層の全表面に表面層を形成した後、この表面層を１６０℃で、３０分間乾燥させ、帯電ロールを作製した。
【０２２０】
この帯電ロールに関し、抵抗測定セル（商品名：１６００８Ａ、ＹＨＰ社製）及び抵抗計（商品名：Ｒ８３４０Ａ、アドバンテスト社製）を用いて、印加電圧１００Ｖで体積抵抗を測定した。前記中抵抗弾性層の表面にロールと同様に表面層を設けたシート（帯電ロールの層構成に相当）の体積抵抗は、１０^5.2Ω・ｃｍを示した。また表面層の体積抵抗は１０^4.5Ω・ｃｍであり、帯電ロールと表面層の体積抵抗の差は、０．７桁であった。また、放電絶縁破壊を起こす電圧を測定したところ、２２００Ｖであった。このときの表面被覆率は９５．６％であった。なお、上記表面被覆率は、次の式を用いて算出した。
表面被覆率（％）＝〔（表面層の全表面積）／（帯電ロールの全表面積）〕×１００
【０２２１】
[転写ロールの作製]
２層構成転写ロールを、以下のように作製した。
加硫剤として、硫黄１質量部と、加硫促進剤としてテトラメチルチラウムジサルファイド０．６質量部とを含有するゴム素材（ ＥＰＤＭ ＥＰ３３：日本合成ゴム（株）製）１００質量部に、ケツチエンブラック（ライオンアグゾ（株）製、体積抵抗ρv：１０^6.3Ωｃｍ）１２質量部およびＦＴカーボン（旭カーボン（株）製）２０質量部と、発泡剤としてベンゼンスルホニルヒドラジド６質量部の組成からなる発泡ゴムコンパウンド１５質量部とを加え、ニーダーおよびロール練り機により混練した。
【０２２２】
次いで、この混練物を、押出機でチューブ形状に押出成形し、これを加硫缶内で温度１２６ ℃、 圧力１．５ｋｇ／ｃｍ²Ｇの加圧蒸気下に加熱発泡した。得られた発泡弾性体に、ステンレス製のシャフト（直径：８ｍｍ、長さ：３５０ｍｍ）を挿入し、さらに厚み０．１ｍｍのポリフッ化ビニリデン（ＰＶＤＦ）樹脂にイオン導電性ポリマーを分散してなる熱収縮チューブを、１２０℃にて被覆することにより、層厚が５ｍｍの転写ロールを得た。
【０２２３】
なお、前記発泡弾性体（下地層）の硬度は、アスカーＣ硬度で６０°であり、ロール硬度はアスカーＣ硬度で４０°であった。上記ポリフッ化ビニリデン（ＰＶＤＦ）の体積抵抗率は、１０^8.2Ωｃｍ、表面抵抗は１０^7.5Ω／□ であった。また、イオン導電性ポリマーを分散してなるＰＶＤＦチューブは、ＰＶＤＦ粉末にイオン導電性ポリマーとして、三洋化成工業（株）製のペレスタット６３２１チップを４０質量％混合し、これを二軸押出機で混練しつつペレット化し、これを一軸押出機でチューブ状に延伸しながら押し出し成形を行って得られる。
【０２２４】
＜実施例１＞
評価機として、複写機（Ｌａｓｅｒ Ｗｉｎｄ３３１０：富士ゼロックス社製）改造機を用い、前記帯電ロールを感光体に接触回転するように設置し、そのシャフト（導電性支持体）に電源から、画像形成時のみ７５０ＶのＤＣ電源と２ｋＶで２ｋＨｚのＡＣ電源とを重畳したものを印加するようにした。また、前記転写ロールも同時に設置した。
【０２２５】
上記複写機の現像器に、現像剤として前記現像剤１をセットし、２３℃、５５％ＲＨの環境下で、連続４０００枚の連続走行試験を行った。トナー帯電量維持性、画質、用紙剥離性、転写・帯電ロール汚れ、転写画質での画質欠陥（ホロキャラ、端部白抜け）等を評価した。
【０２２６】
−トナー帯電量維持性−
初期及び走行試験後のトナー帯電量を帯電量測定器ＴＢ２００（東芝社製）により測定し、以下の基準により評価した。
【０２２７】
○：走行試験後の帯電量低下が５μＣ／ｇ未満
△：走行試験後の帯電量低下が５μＣ／ｇ以上１０μＣ／ｇ未満
×：走行試験後の帯電量低下が１０μＣ／ｇ以上
【０２２８】
−画像濃度−
走行試験後の全面ベタ画像を出力し、画像濃度均一性を目視により、以下の基準により評価した。
○：全面均一で問題なし。
△：濃度ムラが見られる。
×：全体的に濃度低下している。
【０２２９】
−かぶり−
走行試験後の白地画像について、目視により以下の基準で評価した。
○：かぶりなし。
△：ややかぶりが見られる。
×：かなりかぶりが見られ品質上問題。
【０２３０】
−粒状性−
走行試験後の中間調画像を出力し、目視により以下の基準で評価した。
○：全面均一で問題なし。
△：ややざらつきが見られる。
【０２３１】
−転写効率−
初期及び走行試験後の転写効率を求め、以下の基準により評価した。なお、転写効率は、ベタ画像について、記録用紙に転写された単位面積当りのトナー量（ＴＭＡ）と、感光体表面に残る未転写の単位面積当りのトナー量（ＤＭＡ）を測定し、以下の式により算出した。
転写効率（％）＝〔（ＴＭＡ）／（ＴＭＡ＋ＤＭＡ）〕×１００
【０２３２】
○：転写効率がほとんど低下しない。
△：転写効率が５％以上１０％未満低下。
×：転写効率が１０％以上低下。
【０２３３】
−ホローキャラクター、白抜け−
走行試験後の細線（英文）画像について、目視により以下の基準で評価した。
○：良好
△：軽微に発生
×：発生
【０２３４】
−ロールの汚れ状態 −
走行試験後の帯電ロール、転写ロールを取り外し、スコッチテープにより表面に付着しているトナーを転写して、目視により以下の基準で評価した。
以上の評価結果を表２に示す。
【０２３５】
＜実施例２〜７、比較例１〜６＞
実施例１において、現像剤１の代わりに、現像剤２〜７を各々用いた以外は実施例１と同様にして実施例２〜７を行った。
また、実施例１において、現像剤１の代わりに、現像剤８〜１３を各々用いた以外は実施例１と同様にして比較例１〜６を行った。
結果をまとめて表２に示す。
【０２３６】
【表２】

【０２３７】
表２の結果に示すように、実施例の現像剤を用いた場合には、トナー帯電性、画質欠陥がほとんどなく、トナー性能として安定しているだけでなく、帯電ロールや転写ロールへの汚染が全くないことがわかった。一方、比較例の現像剤を用いた場合には、トナー性能や上記汚染等に何らかの問題が発生した。特に、粗大顔料粒子量が多い比較例３〜６では、帯電量低下によるかぶり、濃度ムラ、ロール汚染や転写効率低下、画像欠陥が発生しており、著しく劣る結果となった。
【０２３８】
【発明の効果】
本発明によれば、環境安定性や繰り返し安定性に優れ、良好な帯電性能、転写性能を有し、高画質と高信頼性とを同時に満足し得る画像形成方法、画像形成装置を提供することができる。
【図面の簡単な説明】
【図１】本発明の画像形成装置の一例である電子写真装置を示す模式断面図である。
【符号の説明】
１ 静電潜像担持体
２ クリーニングブレード
３ 保持部材
１０ 電子写真感光体（静電潜像担持体）
１１ 帯電器（帯電手段）
１２ 電源
１３ 画像入力器（静電潜像形成手段）
１４ 現像器（現像手段）
１５ 転写器（転写手段）
１６ クリーニング器（クリーニング手段）
１７ 除電器
１８ 定着器
１９ ブレード（クリーニングブレード）
２０ 被記録体
２１ 箱体[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming method and an image forming apparatus using an electrophotographic method or an electrostatic recording method.
[0002]
[Prior art]
Methods for visualizing image information via an electrostatic latent image, such as electrophotography, are currently used in various fields. In the electrophotographic method, an electrostatic latent image is formed on the surface of a photoreceptor (electrostatic latent image carrier) by a charging and exposing process, and the toner for developing an electrostatic image (hereinafter, may be simply referred to as “toner”). The electrostatic latent image is developed with an electrostatic image developer (hereinafter, may be simply referred to as “developer”) containing, and is visualized through a transfer and fixing process.
[0003]
In the charging process in the electrophotographic process, the photosensitive member is conventionally charged by corona discharge generated by applying a high voltage to a metal wire. However, in this method, ozone, NOx, and the like are generated when the corona discharge occurs. In addition, there has been a problem that the surface of the photoreceptor is deteriorated to cause image blur and black streaks, and that charging efficiency is poor. For this reason, in recent years, many methods have been devised for directly charging the photoreceptor instead of such charging by corona discharge. Above all, the contact state of the charging roll (charging member) with the photoconductor is stable, the occurrence of pinhole leak is suppressed, and the state of the nip formation is stable.
[0004]
The charging roll used in the contact charging system has a medium resistance of 10 on the outer periphery of a conductive metal such as stainless steel or Ni plated metal.^Four-10⁹An elastic body of Ω · cm is arranged. The reason why the elastic body has the medium resistance is to improve the charging efficiency and to prevent the occurrence of a charging failure due to a voltage drop caused by a charging current leak to a photosensitive member defect.
[0005]
A contact charging device using a charging roll is used in contact with a photoreceptor as a member to be charged, and a DC voltage and an oscillating voltage are applied from the charging device in a superimposed manner (for example, see Patent Document 1). However, when a superimposed voltage is applied, due to electrical and mechanical vibrations caused by the oscillating voltage component, a fused portion of toner is generated on the surface of the photoreceptor, and abrasion of the surface of the photoreceptor is promoted. This causes a problem that image quality is impaired. Further, when high image quality such as color printing is required, it is necessary to perform a charge removing step before uniformly charging the photoconductor. In this case, especially in a low-temperature and low-humidity environment such as in winter, if the superimposed voltage of the DC voltage component and the oscillating voltage component is continuously applied to the contact charging device, the charging capability of the contact charging device is reduced, and image quality defects occur.
[0006]
In order to solve this problem, there has been proposed a method of applying neither a DC voltage nor an oscillating voltage to the charging roll when an image is not formed (see, for example, Patent Document 2). , And the charging performance can be stably maintained for a long period of time.
[0007]
On the other hand, in this type of image forming apparatus, a toner image visualized by developing an electrostatic latent image on the surface of a photoreceptor is electrostatically transferred to a recording medium such as a recording paper via an intermediate transfer member or directly. By transferring, a required reproduced image is obtained. In particular, in a method employing a method in which a toner image formed on the electrostatic latent image carrier is primarily transferred to an intermediate transfer member, and a toner image on the surface of the intermediate transfer member is secondarily transferred to recording paper, a conductive bias is used. 2. Description of the Related Art A bias roll type image forming apparatus is known in which a recording paper is pressed against an intermediate transfer body using a roll, and an electric field is applied to transfer a toner image electrostatically. A bias roll transfer method for performing electrostatic transfer while applying a transfer voltage to a conductive bias roll includes a backup roll that receives a pressing force of the bias roll and forms a path for a transfer current.
[0008]
In a transfer device using a metal roll as a bias roll (for example, see Patent Document 3), a recording sheet is pressed against a backup roll by a bias roll via an intermediate transfer member, so that the toner image is electrostatically charged by the action of an electric field. The load of the pressing force by the bias roll concentrates on the secondary transfer portion where the image is transferred. For this reason, the toner image may be aggregated, the charge density may be increased, and a discharge may occur inside the toner layer to change the toner polarity. Due to such factors, the above-described conventional technology has a problem in that an image quality defect of a hollow character in which a line image is missing occurs. The state of the toner particles and the toner layer is greatly related to the hollow character, and in particular, those having a small particle size, an irregular shape, easily causing a charge leak, and a low insulating property are easily affected.
[0009]
Further, between the time when the sheet passes through the bias roll and the time when the next sheet is conveyed to the bias roll, the toner remaining on the intermediate transfer member is transferred to the bias roll, and the bias roll is contaminated. In order to solve this problem, a method of cleaning a bias roll with a cleaning blade or the like, and a method of forming an electric field between the bias roll and the image carrier in a direction in which toner is transferred to the image carrier during non-transfer are provided. However, when the hardness of the bias roll is relatively low, it is difficult to sufficiently exert the scraping action of the cleaning blade. On the other hand, when the bias roll is made of a rubber material having a large friction coefficient, it is not practical because the sliding of the blade damages the bias roll and increases the rotational torque. Further, the adhered toner is pressed by the bias roll and easily aggregates. Therefore, a high electric field is required for sufficient cleaning, which is not preferable.
[0010]
In recent years, in this type of image forming apparatus, the image quality has been improved, and as one direction for the improvement of the image quality, the diameter of the toner has been reduced. By reducing the diameter, the reproducibility of dots of a toner image formed on the surface of the latent image carrier can be improved.
[0011]
By the way, as for the method of producing the toner, if the diameter of the toner is simply reduced by a pulverization method, which is one of the methods for producing the toner which has been widely used, the yield in producing the toner is deteriorated. Cost is high.
[0012]
Further, the shape of toner particles produced by the conventional kneading and pulverizing method is irregular, and the surface composition is not uniform. Although the shape and surface composition of the toner particles slightly change depending on the pulverizability of the materials used and the conditions of the pulverization process, it is difficult to control the shape of the toner and the surface composition of the toner particles intentionally. Further, when toner particles are produced using a material having particularly high pulverizability, the generation of fine powder or a change in shape often occurs due to mechanical force or the like caused by shearing force in the developing device.
[0013]
Due to these effects, in the two-component developer, the finely-divided toner particles adhere to the carrier to accelerate the charge deterioration of the developer, and in the one-component developer, the toner particle size is increased due to the expansion of the particle size distribution of the toner particles. Image quality is likely to be deteriorated due to scattering or a decrease in developability due to a change in the shape of the toner particles.
[0014]
Also, if the shape of the toner particles is irregular, the fluidity is not sufficient even when the fluidity aid is added, and the fine particles of the fluidity aid enter the recesses of the toner particles due to mechanical force such as shear force during use. There is a problem that the toner is buried, and the fluidity of the toner decreases over time, and the developing property, the transfer property, and the cleaning property deteriorate. Further, if such toner is collected by cleaning and returned to the developing device and used again, the image quality is likely to deteriorate. In order to prevent these phenomena, it is conceivable to further increase the flow aid, but in this case, there is a problem that a black spot on the surface of the photoreceptor is generated or the flow aid is scattered. .
[0015]
On the other hand, in the case of a toner in which a release agent such as wax is added, exposure of the release agent to the surface of toner particles often occurs in combination with a thermoplastic resin. In particular, in the case of a toner in which a resin whose elasticity is imparted by a high molecular weight component and which is not easily crushed and a brittle wax such as polyethylene are combined, polyethylene is often exposed on the surface of the toner particles. Such a toner is advantageous for the releasability at the time of fixing and cleaning of untransferred toner from the photoreceptor, but the polyethylene on the surface of the toner particles is detached from the surface of the toner particles due to a shearing force in a developing device. Easily transfer to a developing roll, a photoreceptor, a carrier or the like. These contaminations reduce the reliability of the developer.
[0016]
Under these circumstances, in recent years, attempts have been made to solve the above-mentioned problem by intentionally controlling the shape and surface composition of toner particles. In particular, studies for producing toner by a wet method have been actively conducted. Was. For example, a resin particle dispersion is prepared by emulsion polymerization or the like, a colorant dispersion in which a colorant is dispersed in an aqueous medium (solvent) is prepared, and both are mixed and heated to form aggregated particles corresponding to the toner particle diameter. Further, an emulsion polymerization aggregation method in which the temperature is further raised to fuse the aggregated particles to produce a toner has been proposed (for example, see Patent Documents 5 and 6).
[0017]
In recent years, there has been an increasing demand for higher image quality. In particular, in color image formation, in order to realize a high-definition image, the toner tends to have a smaller diameter and a uniform particle diameter. Generally, when an image is formed using a toner having a wide particle size distribution, the toner on the fine powder side in the particle size distribution may cause contamination of a developing roll, a charging roll, a charging blade, a transfer roll, an intermediate transfer body, a photoconductor, a carrier, and the like. The problem of toner scattering became remarkable, and it was difficult to achieve high image quality and high reliability at the same time.
Further, a toner having a wide particle size distribution has a wide distribution of chargeability of the toner itself, and in a developing process and a transferring process, a problem of fogging and scattering easily occurs, and it is difficult to obtain high reliability in these processes. .
[0018]
On the other hand, a toner having a small particle diameter tends to generate various types of dribbles particularly in a transfer process, which is a factor that hinders improvement in image quality. This is believed to be due to an increase in the non-electrostatic adhesion of the toner to the photoreceptor, for example, van der Waals force. In order to improve such a problem, it is necessary to appropriately control the adhesive force between the toner and the photoreceptor. For example, it is necessary to control the shape and the surface state.
[0019]
With the conventional kneading and pulverizing method, it is very difficult to produce a toner having a small particle size and a uniform particle size as described above. Problems in the process cannot be avoided. Therefore, among the wet methods, researches on an emulsion polymerization aggregation method, which is particularly easy to produce a toner having a small diameter and a uniform particle diameter, are being actively conducted.
[0020]
However, in the case of producing toner particles by the emulsion polymerization aggregation method, generally, the reaction proceeds in a direction in which the shape of the irregular toner particles is converted into a smoother spherical toner by heating, that is, a direction in which the surface area is reduced. Therefore, the toner has the principle surface that the smaller the surface area of the toner, that is, the smaller the particle size, the higher the sphericity and the larger the particle size, the higher the irregularity. On the other hand, in order to obtain all of the transfer quality, transfer efficiency, toner durability, and the like of the toner shape, an optimal design in the toner particle shape and particle size distribution is required.
[0021]
On the other hand, when the contact charging device using the charging roll is used, there is a problem that the charging roll is in contact with the member to be charged (electrostatic latent image carrier) due to the principle of the contact charging device. Dirt and foreign matter on the surface of the body to be charged are transferred, and the accumulation tends to cause a contaminated state, and when the contaminated state becomes unacceptable, the charged body cannot be charged to a desired potential or uneven charging occurs, The charging performance may be reduced. In particular, when a toner having a small particle size for obtaining a high-definition color image is used, there is a problem that the charging roll is significantly contaminated and a desired uniform charge cannot be obtained.
[0022]
Also, when a transfer roll is used, dirt and foreign matter on the surface of the transfer target such as the photoreceptor and the intermediate transfer body migrate, and the accumulation tends to cause a contamination state. If the contamination state exceeds an allowable level, a transfer current leak occurs. However, there has been a problem that uniform transfer cannot be obtained. Also. When the toner insulating property is low and the particle size and the shape distribution are wide, there has been a problem that the hollow character is particularly deteriorated.
[0023]
[Patent Document 1]
JP-A-1-073364
[Patent Document 2]
JP 2000-352857 A
[Patent Document 3]
JP-A-06-095521
[Patent Document 4]
JP-A-06-095521
[Patent Document 5]
JP-A-63-282849
[Patent Document 6]
JP-A-6-250439
[0024]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-mentioned problems of the conventional technology.
That is, the present invention provides an image forming method and an image forming apparatus which are excellent in environmental stability and repetition stability, have good charging performance and transfer performance, and can simultaneously satisfy high image quality and high reliability. Aim.
[0025]
[Means for Solving the Problems]
The above object is achieved by the present invention described below. That is, the present invention
<1> a charging step of bringing a charging member into contact with an electrostatic latent image carrier and applying a voltage from outside to perform charging, an electrostatic latent image forming step of forming an electrostatic latent image, and the electrostatic latent image A toner image forming step of visualizing the toner image with an electrostatic image developer, wherein the electrostatic image developer has the following conditions (a), (b), and (c): , (D) and (e), the image forming method comprising an electrostatic image developing toner.
[0026]
(A) The volume average particle diameter D50v of the toner is in the range of 3 to 10 μm, and both the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are 1.25 or less.
(B) the particle size distribution index GSDp-under on the small particle size side is 1.27 or less, and the particle ratio of the particle size not more than 3/5 of the number average particle size D50n is 10 number% or less, and the volume average particle size is The ratio of particles having a particle diameter twice or more of D50v is 10% by volume or less.
(C) The average circularity is in the range of 0.940 to 0.980, and the average circularity standard deviation is 0.1 or less.
(D) The number of agglomerates of pigment particles having a maximum length of 1 μm or more, which is observed in a toner cross-sectional image observed by a transmission electron microscope, is 5% by number or less in one toner, and the pigment particles in the toner are Has an average dispersion diameter of 0.1 to 0.7 μm.
(E) Group IA element (excluding hydrogen), IIA element, IIIB element, and IVB element (carbon, assuming that the entire detection element intensity ratio by fluorescent X-ray analysis is 100%) ) Is in the range of 0.1 to 10%.
[0027]
<2> Charging means for bringing a charging member into contact with an electrostatic latent image carrier and applying a voltage from the outside to perform charging, an electrostatic latent image forming means for forming an electrostatic latent image, and the electrostatic latent image And a toner image forming unit for visualizing the toner image using an electrostatic image developer, wherein the electrostatic image developer is provided with the following conditions (a), (b), and (c). , (D), and (e), the image forming apparatus includes an electrostatic image developing toner.
[0028]
(A) The volume average particle diameter D50v of the toner is in the range of 3 to 10 μm, and both the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are 1.25 or less.
(B) the particle size distribution index GSDp-under on the small particle size side is 1.27 or less, and the particle ratio of the particle size not more than 3/5 of the number average particle size D50n is 10 number% or less, and the volume average particle size is The ratio of particles having a particle diameter twice or more of D50v is 10% by volume or less.
(C) The average circularity is in the range of 0.940 to 0.980, and the average circularity standard deviation is 0.1 or less.
(D) The number of agglomerates of pigment particles having a maximum length of 1 μm or more, which is observed in a toner cross-sectional image observed by a transmission electron microscope, is 5% by number or less in one toner, and the pigment particles in the toner are Has an average dispersion diameter of 0.1 to 0.7 μm.
(E) Group IA element (excluding hydrogen), IIA element, IIIB element, and IVB element (carbon, assuming that the entire detection element intensity ratio by fluorescent X-ray analysis is 100%) ) Is in the range of 0.1 to 10%.
[0029]
Further, in the present invention, it is preferable that the charging unit is formed by using a charging roll, and the charging roll has an ion conductive elastic material layer on a conductive support, and a surface layer in which an electronic conductive material is dispersed. It is preferable that the layers are sequentially laminated. Further, the ionic conductive elastic layer is preferably formed by mixing at least one quaternary ammonium salt with urethane rubber or epichlorohydrin rubber, and the thickness of the surface layer is in the range of 2 to 500 μm. It is preferable that
[0030]
As the transfer means, a transfer roll using a transfer roll is preferable. The transfer roll has a structure of two or more layers, the base layer is formed of a conductive foam layer, and a thickness of 0.1 mm is formed on the outside of the conductive foam layer. Preferably, an elastic layer of 1 to 1.0 mm is covered. In the transfer roll, it is preferable that the base layer is formed of a conductive foam layer having an Asker C hardness of 40 ° or less, and the roll hardness is 45 ° or less.
[0031]
It is preferable that the image forming apparatus includes an intermediate transfer body for carrying the primary transfer and a means for secondarily transferring the unfixed toner image of the intermediate transfer body to a recording medium.
[0032]
Further, the toner for developing an electrostatic image is prepared by mixing a dispersion of fine resin particles, a dispersion of colorant, a dispersion of release agent, and a dispersion of fine inorganic particles, and aggregating the mixture at a temperature equal to or lower than the glass transition temperature (Tg) of the fine resin particles. After forming the particle dispersion, the toner is preferably obtained by fusing by heating to a temperature equal to or higher than the glass transition point of the resin fine particles, and particularly, a resin fine particle dispersion, a colorant dispersion, and a release agent dispersion. When mixing the inorganic fine particle dispersion and the inorganic fine particle dispersion, it is preferable to perform the mixing at a temperature lower by at least 25 ° C. than the Tg of the resin fine particles.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
<Image forming method>
The image forming method of the present invention includes a charging step of applying a voltage from the outside by bringing a charging member into contact with an electrostatic latent image carrier to perform charging, and an electrostatic latent image forming step of forming an electrostatic latent image, A toner image forming step of visualizing the electrostatic latent image using an electrostatic image developer, wherein the electrostatic image developer satisfies specific conditions described below. An image forming method comprising an electrostatic image developing toner.
Hereinafter, the components of the present invention will be described.
[0034]
The electrostatic image developing toner used in the present invention is an electrostatic image developing toner satisfying the following conditions (a), (b), (c), (d) and (e).
Hereinafter, each condition will be described.
[0035]
-Condition (a)-
The first condition is that the toner volume average particle diameter D50v is in the range of 3 to 10 μm, and the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are both 1.25 or less.
[0036]
The volume particle size distribution index GSDv and the number particle size distribution index GSDp are obtained as follows. First, for example, based on the particle size distribution measured by a measuring instrument such as a Coulter Counter TAII (manufactured by Nikkaki Co., Ltd.), the volume and the number are each subtracted from the small particle size side by the cumulative distribution to obtain a cumulative 16%. The particle diameter resulting in a volume D16v and a number D16p, and the particle diameter providing a cumulative 50% is defined as a volume D50v, a number D50p, and the particle diameter providing a cumulative 84% as a volume D84v and a number D84p.
And the volume particle size distribution index GSDv is (D84v / D16v)^1/2And the number average particle size distribution index GSDp is (D84p / D16p)^1/2Is calculated as
[0037]
When the volume average particle diameter D50v is less than 3 μm, the chargeability becomes insufficient, and scattering to the surroundings occurs to cause image fog, which is not preferable. On the other hand, if it exceeds 10 μm, the resolution of the image is reduced, and it is difficult to achieve high image quality. On the other hand, if GSDv and GSDp exceed 1.25, the dispersion of the particle size distribution becomes large, and the graininess and resolution of the image may decrease, which is not preferable. In addition, since the shape distribution tends to be widened, cleaning and transfer maintaining properties may be unfavorably affected.
[0038]
-Condition (b)-
As the second condition, the small particle size side number particle size distribution index GSDp-under is 1.27 or less, and the particle ratio of the particle size of 3/5 or less of the number average particle size D50n is 10% by number or less, It is necessary that the ratio of particles having a particle diameter twice or more the volume average particle diameter D50v is 10% by volume or less.
[0039]
The small particle size side average number particle size distribution index GSDp-under is D16p, which is obtained as a particle size value that becomes 16% cumulative from the small particle size side in the particle size distribution, and 50% cumulative particle size in the same manner as described above. It is calculated as (D50p / D16p) from D50p obtained as the particle size value.
[0040]
When the GSDp-under exceeds 1.27, the ratio of the small particle size toner becomes high, which has an extremely large influence not only on the initial performance but also on the reliability. That is, as is conventionally known, since the adhesion of the small particle size toner is large, it is difficult to control static electricity easily, and when a two-component developer is used, the toner tends to remain on the carrier surface. In this case, when mechanical force is repeatedly applied, carrier contamination is caused, and as a result, deterioration of the carrier is promoted. Further, since the small particle size toner has a large adhesive force, a reduction in development efficiency also occurs, resulting in image quality defects.
[0041]
Particularly, in the transfer step, it is easy to transfer a small diameter component of the toner developed on the photoreceptor surface, and as a result, transfer efficiency is deteriorated, resulting in an increase in waste toner and poor image quality.
[0042]
As a result of these problems, toner that is not electrostatically controlled or toner of the opposite polarity increases, and these contaminate the surroundings. In particular, it is not preferable for the charging roll because these electrostatically uncontrolled toners are accumulated via a photoreceptor or the like and cause charging failure.
[0043]
When the proportion of particles having a particle diameter of 3/5 or less of the number average particle diameter D50n exceeds 10% by number, the number of particles having a shape close to a sphere increases, and there is a problem in cleaning stability. In addition, these toner fine particles often do not sufficiently contain pigment particles and release agent particles, and cause poor charging and poor transfer when accumulated on a charging roll or a transfer roll via a photoconductor or the like. Not preferred.
In addition, it is more preferable that the particle ratio of the particle diameter of 3/5 or less of the number average particle diameter D50n is 5% by number or less.
[0044]
If the proportion of particles having a particle diameter more than twice the volume average particle diameter D50v exceeds 10% by volume, many particles having a large particle diameter and a shape close to an irregular shape increase, resulting in poor development, toner scattering from a developing device, and poor transfer. In addition, there are many problems such as toner destruction at the time of cleaning and toner destruction due to rubbing with the charging roll and the transfer roll, and filming. In particular, when the charging roll is contaminated, the roll resistance fluctuates, and black streaks appear in the image. In addition, it is more preferable that the particle ratio of the particle diameter twice or more the volume average particle diameter D50v is 5% by volume or less.
[0045]
-Condition (c)-
The third condition is that the average circularity is in the range of 0.940 to 0.980 and the average circularity standard deviation is 0.1 or less.
The average circularity of the toner is measured by, for example, a flow type particle size measuring device, an image analysis device, or the like. The circumference of a circle having a diameter corresponding to the maximum length of the toner (circumference circumference) and the circumference of an actual toner ( (Perimeter) and (circumference perimeter / perimeter).
[0046]
When the average circularity is less than 0.940, the ratio of irregular shaped particles increases, so that the toner scatters from the developing device, the toner transportability in the developing device is poor, the transfer is poor, and the cleaning roll and the charging roll and the transfer roll There are many problems such as toner destruction due to rubbing and filming. In particular, when the charging roll is contaminated, the roll resistance fluctuates, and black streaks appear in the image.
[0047]
When the average circularity exceeds 0.980, the ratio of spherical particles increases, which causes cleaning failure. When a large amount of toner that has passed through the cleaner adheres to the charging roll and the transfer roll, the roll resistance fluctuates, and black streaks appear in the image.
[0048]
Further, when the average circularity standard deviation exceeds 0.1, the uniformity of the shape is reduced, so that the maintainability of the toner transporting property, the developing property, the transfer property, the cleaning property, the toner breaking resistance and the like is inferior. Therefore, a problem occurs in long-term use, which is not preferable.
[0049]
The toner used in the present invention is characterized in that it has a narrow particle size distribution and a small amount of fine powder despite its small particle size, and its shape is between a spherical shape and an irregular shape. Further, by controlling the ratio of specific elements when the number of coarse agglomerated particles of the pigment particles in the toner is set to a certain value or less and the whole of the intensity ratio of the element detected by fluorescent X-ray analysis is set to 100%, electrophotography is performed. Alternatively, it is possible to provide a good image forming method which satisfies various characteristics of the developing step, the transferring step, the cleaning step, and the fixing step in the electrostatic recording method, and furthermore, there is no toner destruction even after continuous running and no toner passes through the cleaner. That is, since there is little toner adhesion to the charging roll and the transfer roll, it is possible to provide a high-quality image for a long time.
[0050]
-Condition (d)-
A fourth condition is that the number of aggregates of pigment particles having a maximum length of 1 μm or more, which is observed in a toner cross-sectional image observed by a transmission electron microscope, is 5% by number or less in one toner. is necessary.
[0051]
The aggregate of the pigment particles in the toner is obtained by, for example, mixing the toner with an embedding agent such as an epoxy resin, cutting the mixture with a diamond cutter or the like, and then observing the cut body with a transmission electron microscope (TEM). You can check. Then, the size of the pigment particles dispersed therein can be calculated by taking the observed image into the image analyzer.
[0052]
When the number of pigment particles having a maximum length of 1 μm or more is more than 5% by number in one toner, the pigment particles are relatively likely to be present on the surface of the toner, so that the charging characteristics are deteriorated and the background portion of the image is deteriorated. The scattering is increased, and the image quality is impaired, which is not preferable. Even when the toner does not scatter, the low-charged toner remaining on the photoreceptor is taken into the charging roll or the transfer roll, and the roll resistance fluctuates, which may cause black streaks or white spots in the image.
[0053]
Furthermore, if the coarse particles of the pigment particles are present, it is easy to cause destruction at the interface between the pigment and the resin, so that the durability of the toner itself may be affected, and the charge roller, the cleaner, and the transfer roller may be damaged. Rubbing tends to cause toner destruction, which may cause contamination of the photoreceptor, roll, and cleaner.
[0054]
By limiting the number of the coarse pigment particles to 5% by number or less, exposure of the pigment particles to the toner surface can be suppressed, and a toner having excellent durability can be provided. In addition, the dispersion average particle size of the pigment particles is in the range of 0.1 to 0.7 μm, and preferably in the range of 0.2 to 0.5 μm, from the viewpoint of sufficient coloring properties and good dielectric properties.
[0055]
-Condition (e)-
The fifth condition is that a group IA element (excluding hydrogen), a group IIA element, a group IIIB element, and a group IVB, where the entire detection element intensity ratio by fluorescent X-ray analysis is 100%. It is necessary that the ratio of group element (excluding carbon) is in the range of 0.1 to 10%. The above ratio is more preferably in the range of 0.1 to 5%.
[0056]
The group IA element (excluding hydrogen), the group IIA element, the group IIIB element, and the group IVB element (excluding carbon) are defined as the group numbers according to the revised edition of the 1989 inorganic chemical nomenclature of IUPAC. It corresponds to a Group 1 element (excluding hydrogen), a Group 2 element, a Group 13 element, and a Group 14 element (excluding carbon). Representative elements include Li, Na, K, and Rb. , Mg, Ca, Sr, Ba, Al, Si and the like. These elements are water-soluble when formed into hydroxides or chlorides, or water dispersions are obtained as colloids, and thus are incorporated into the toner as a coagulant, a coagulation terminator, and a charge control agent. As a result, it is possible to control the binding of the fine particles (resin, inorganic powder, etc.) constituting the toner.
[0057]
When the ratio of the Group IA element (excluding hydrogen), the Group IIA element, the Group IIIB element, and the Group IVB element (excluding carbon) is less than 0.1%, the toner durability is reduced and the charge is reduced. Rubbing of the roll, cleaner, and transfer roll tends to cause toner destruction, which may cause contamination of the photoconductor, roll, and cleaner.
[0058]
When the ratio of the above elements exceeds 10%, the toner durability is sufficient, but the charging characteristics may be affected depending on the type of the remaining elements. Further, since the toner elastic modulus becomes too high, the toner may be insufficiently melted, which may affect the strength of the fixed image. In addition, sufficient gloss may not be obtained particularly in a color image.
By limiting the proportions of Group IA elements (excluding hydrogen), Group IIA elements, Group IIIB elements, and Group IVB elements (excluding carbon) to the range of 0.1 to 10%, durability is improved. And a toner which is excellent in the durability of a fixed image and which can be used for both color and black.
[0059]
The fluorescent X-ray analysis for confirming the conditions was performed using a fluorescent X-ray analyzer (XRF-1800, manufactured by Shimadzu Corporation) as an apparatus, with an X-ray tube voltage of 40 kV, a filament current of 70 mA, and a sample molding amount of 6 g. The test was performed under the conditions of ± 0.01 g.
[0060]
The toner of the present invention preferably contains a release agent from the viewpoint of obtaining oil-less fixing performance. In that case, the release rate of the release agent on the toner surface determined by X-ray photoelectron spectroscopy (XPS) is preferable. Is preferably in the range of 11 to 40%.
[0061]
When the release rate of the release agent on the toner surface is less than 11%, there is a case where the fixing performance is not initially affected but the long-term maintainability is difficult. Further, when the fixing device is deteriorated, the offset on the high-temperature side and the strength of the fixed image on the low-temperature side may be adversely affected. On the other hand, if it exceeds 40%, although the fixing performance is not affected, filming may occur on the carrier, the developing roll, the photoconductor, the charging roll, and the like. Further, phenomena such as the external additive added for imparting fluidity being buried in the toner are likely to occur.
The exposure rate of the release agent on the toner surface is more preferably in the range of 15 to 30%.
[0062]
The release agent exposure rate can be quantified by separating peaks caused by resin, pigment, and wax by using a measuring device such as an X-ray photoelectron spectrometer (XPS) manufactured by JEOL Ltd.
[0063]
It is preferable that the release agent has a melting point measured by a differential scanning calorimeter in the range of 70 to 130 ° C. and a content in the toner of 8 to 20% by mass. The melting point of the release agent is measured according to ASTM D3418-8.
[0064]
If the melting point of the release agent is less than 70 ° C., offset tends to occur during fixing. On the other hand, when the temperature exceeds 130 ° C., the fixing temperature becomes high, and the smoothness of the surface of the fixed image cannot be obtained, thereby deteriorating the glossiness. When the amount of the release agent is less than 8% by mass, an offset phenomenon at a high temperature may occur. When the amount exceeds 20% by mass, the transparency of the image on the transparent film becomes insufficient, or the release agent An offset may occur, which is not preferable.
[0065]
For the measurement of the melting point (main maximum peak) of the release agent, for example, DSC-7 manufactured by Perkin Elmer Co., Ltd. is used. The temperature correction of the detection unit of the apparatus uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.
[0066]
The toner of the present invention may contain 0.5 to 10% by mass of inorganic fine particles having a central particle size of 5 to 30 nm and inorganic fine particles having a central particle size of 30 to 100 nm. It is preferable in terms of durability.
[0067]
Examples of the inorganic fine particles include silica, hydrophobized silica, titanium oxide, alumina, calcium carbonate, magnesium carbonate, tricalcium phosphate, colloidal silica, colloidal silica having a cationic surface treatment, and colloidal silica having an anion surface treatment. These inorganic fine particles are previously subjected to dispersion treatment using an ultrasonic disperser or the like in the presence of an ionic surfactant, and it is more preferable to use colloidal silica which does not require this dispersion treatment.
[0068]
When the amount of the inorganic fine particles is less than 0.5% by mass, sufficient toughness cannot be obtained at the time of melting the toner even by the addition of the inorganic fine particles. Coarse dispersion of the fine particles in the toner increases only the viscosity, resulting in poor spinnability and sometimes impairing oilless releasability. If the content exceeds 10% by mass, sufficient toughness can be obtained, but the fluidity at the time of melting the toner is greatly reduced, and the image gloss may be impaired.
[0069]
The image forming method according to the present invention includes a charging step in which a charging member is brought into contact with an electrophotographic photosensitive member (electrostatic latent image carrier) to apply a voltage from outside to perform charging, and an electrostatic latent image for forming an electrostatic latent image. An image forming step, a toner image forming step of visualizing the electrostatic latent image using an electrostatic image developer, and further a toner image on the surface of the electrophotographic photosensitive member is transferred to a transfer member (recording member or intermediate transfer member). And a cleaning step of removing residual toner on the surface of the electrophotographic photosensitive member.
[0070]
As the charging roll used for the charging member in the present invention, a charging roll formed by sequentially laminating an ionic conductive elastic layer and a surface layer in which an electronic conductive substance is dispersed on a conductive support surface is preferable.
[0071]
Examples of the ionic conductive elastic layer include urethane rubber, epichlorohydrin rubber, polyether urethane rubber, polyester urethane rubber, chloroprene rubber, NBR, EPDM blended NBR rubber, SBR rubber, butyl rubber, and the like. It is preferable to mix various alkyl ammonium salts having a quaternary ammonium salt structure. The amount of compounding or the amount of dispersion is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.1 to 10% by mass.
The volume resistance of the ionic conductive elastic layer is 10^Three-10^TenIt is preferable to be in the range of Ωcm.
[0072]
As the binder resin used for the surface layer, polyester, polyamide, polyurethane, melamine resin, acrylic resin such as polymethyl methacrylate (PMMA) or polymethylbutyl acrylate (PMBA), polyvinyl butyral, polyvinyl acetal, polyarylate, Examples thereof include polycarbonate, phenoxy resin, polyurea, and polyvinyl acetate.
[0073]
Various conductive carbon blacks or metal oxides can be used as the electronic conductive substance mixed in the resin, and it is preferable to disperse these and adjust the resistance. The amount of compounding or the amount of dispersion is preferably in the range of 0.01 to 20% by mass, more preferably in the range of 0.1 to 10% by mass.
Further, the thickness of the surface layer is preferably formed in the range of 2 to 500 μm, and more preferably in the range of 20 to 200 μm.
[0074]
The volume resistance of the charging roll configured as described above is 10^Three-10⁹The range of Ω is preferred. The roll volume resistance was measured at an applied voltage of 100 V / cm using a circular electrode (for example, HP probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.) in accordance with JIS K6991.
[0075]
The transfer roll used for the transfer member in the present invention preferably has a structure in which two or more layers are provided on the surface of the conductive support. The underlayer (foam layer) is made of a conductive foam layer, and it is preferable to form an elastic layer having a thickness in the range of 0.1 to 1.0 mm outside the conductive foam layer.
[0076]
By setting the thickness of the elastic layer to 0.1 mm or more, the nip portion is not locally deformed in the transfer portion, so that there is a problem that the sheet is peeled along the opposing intermediate transfer member and the photosensitive member side. Absent. That is, the deformation of the nip portion is caused by the elastic layer being pressed by the nip pressure over the entire nip portion. For this reason, the curvature of the nip portion is increased, and the same effect as when a transfer roll having a large outer diameter represented by a virtual line is pressed is obtained. As a result, the paper is peeled along the transfer roll having a large curvature. In addition, paper releasability is improved.
[0077]
When the thickness of the elastic layer is 1.0 mm or less, the nip pressure applied to the elastic layer is alleviated by the underlying foam layer, so that the contact pressure of the transfer member can be reduced. Therefore, since the load of the pressing force by the bias roller does not concentrate on the transfer member, there is no problem that image quality defects such as a hollow character in which a line image falls out are generated.
[0078]
In the transfer roll used in the transfer member of the present invention, it is preferable that the base layer is formed of a conductive foam layer having an Asker C hardness of 40 ° or more, and the roll hardness is 45 ° or less in Asker C hardness. By the synergistic action with the elastic layer, local deformation of the nip portion is avoided, and paper releasability due to desired deformation of the nip portion is improved.
[0079]
The resistance value of the transfer roll configured as described above is 10⁷-10¹²The range of Ω is preferred. The roll resistance was measured by the same method as that for the charging roll.
[0080]
Further, the toner for developing an electrostatic image according to the present invention is obtained by mixing a dispersion of resin fine particles, a dispersion of colorant, a dispersion of release agent, and a dispersion of inorganic fine particles, and having a temperature equal to or lower than the glass transition temperature (Tg) of the resin fine particles. After forming the aggregated particle dispersion, the toner is preferably heated to a temperature equal to or higher than the glass transition point of the resin fine particles and fused.
[0081]
When mixing the resin fine particle dispersion, the colorant dispersion, the release agent dispersion and the inorganic fine particle dispersion, it is preferable to carry out the mixing at a temperature lower by at least 25 ° C. than the Tg of the resin fine particles. If the temperature is higher than this range, due to the difference in electrostatic stability between the resin fine particle dispersion, the colorant dispersion, the release agent dispersion, and the inorganic fine particles, the aggregation gradually starts from a low stability. As a result, the toner internal structure becomes uneven. In particular, when the colorant particles aggregate to form a non-uniform structure, it becomes difficult to control the toner particle size distribution, control the shape distribution, secure durability, and secure charging performance, or the condition (d) required for the toner. Can not be satisfied.
[0082]
Further, the toner for developing an electrostatic image according to the present invention is, specifically, at least a resin fine particle dispersion in which resin particles are dispersed, a colorant dispersion, a release agent dispersion, and a mixture of inorganic fine particle dispersion. A first step (aggregation step) of forming aggregated particles and preparing an aggregated particle dispersion, and adding and mixing a fine particle dispersion in which fine particles are dispersed in the aggregated particle dispersion to adhere the fine particles to the aggregated particles. It is preferable to manufacture by a method including a second step (adhering step) of forming adhering particles by heating and a third step (fusing step) of heating and adhering the adhering particles.
[0083]
It is desirable that the second step be performed a plurality of times. In the second step, a release agent fine particle dispersion obtained by dispersing release agent fine particles is added and mixed in the aggregated particle dispersion, and the release agent fine particles are adhered to the aggregated particles to form adhered particles. Thereafter, a step of adding and mixing a resin-containing fine particle dispersion obtained by dispersing the resin-containing fine particles, and further adhering the resin-containing fine particles to the adhering particles to form adhering particles is preferable.
[0084]
In the second step, the colorant fine particle dispersion obtained by dispersing the colorant fine particles is added to and mixed with the aggregated particle dispersion of the resin fine particles, and the colorant fine particles are adhered to the aggregated particles. Is formed, and then a resin-containing fine particle dispersion obtained by dispersing the resin-containing fine particles is added and mixed, and the resin-containing fine particles are further adhered to the adhered particles to form adhered particles.
[0085]
Further, in the second step, the resin-containing fine particles obtained by dispersing the resin-containing fine particles in the aggregated particle dispersion are added and mixed, and the resin-containing fine particles are attached to the aggregated particles to form the adhered particles. It is preferable that the step of adding and mixing an inorganic fine particle dispersion obtained by dispersing the fine particles and further adhering the inorganic fine particles to the attached particles to form the attached particles.
[0086]
In the second step, the fine particle dispersion is added to and mixed with the aggregated particle dispersion prepared in the first step, and the fine particles are adhered to the aggregated particles to form adhered particles. The fine particles correspond to particles newly added to the aggregated particles as viewed from the aggregated particles, and thus may be referred to as “additional particles”.
[0087]
The method of adding and mixing the fine particle dispersion is not particularly limited. For example, the method may be performed gradually and continuously, or may be performed in a plurality of steps and stepwise. In this manner, by adding and mixing the fine particles (additional particles), generation of fine particles can be suppressed, and the particle size distribution of the obtained electrostatic image developing toner can be sharpened. When the addition and mixing are performed stepwise by dividing into a plurality of times, a layer of the fine particles is layered on the surface of the agglomerated particles in a stepwise manner. A composition gradient can be provided, the surface hardness of the particles can be improved, and the particle size distribution can be maintained and the fluctuation can be suppressed during the fusion in the third step, and the stability at the time of fusion can be suppressed. It is advantageous in that it eliminates the need for the addition of a surfactant or a stabilizer such as a base or an acid to enhance the property, and can minimize the amount of such addition, thereby reducing costs and improving quality. It is.
[0088]
Examples of the polymer serving as the thermoplastic binder resin used for the resin particles in the present invention include styrenes such as styrene, parachlorostyrene and α-methylstyrene; methyl acrylate, ethyl acrylate and n-acrylate. Esters having a vinyl group such as -propyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; acrylonitrile, methacrylonitrile Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polyolefins such as ethylene, propylene and butadiene Such as monomers, copolymers obtained by combining two or more of these, or mixtures thereof, furthermore, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyethers. Non-vinyl condensed resins such as resins, mixtures of these with the vinyl resins, and graft polymers obtained when polymerizing vinyl monomers in the coexistence of these. These resins may be used alone or in combination of two or more.
[0089]
Among these resins, vinyl resins are particularly preferred. A vinyl resin is advantageous in that a resin particle dispersion can be easily prepared by emulsion polymerization or seed polymerization using an ionic surfactant or the like.
[0090]
The method for preparing the dispersion of the resin particles is not particularly limited, and a method appropriately selected according to the purpose can be adopted. For example, the dispersion can be prepared as follows.
[0091]
When the resin in the resin particles is a homopolymer or a copolymer (vinyl resin) of a vinyl monomer such as the ester having a vinyl group, the vinyl nitrile, the vinyl ether, or the vinyl ketone. The resin particles made of a homopolymer or a copolymer of the vinyl monomer by subjecting the vinyl monomer to emulsion polymerization or seed polymerization in an ionic surfactant. Can be prepared.
[0092]
When the resin in the resin particles is a resin other than the homopolymer or copolymer of the vinyl monomer, if the resin is soluble in an oily solvent having a relatively low solubility in water, The resin is dissolved in the oily solvent, and the resulting solution is added to the water together with the ionic surfactant and the polymer electrolyte, dispersed in fine particles using a disperser such as a homogenizer, and then heated or reduced in pressure. It can be prepared by evaporating the oily solvent.
[0093]
When the resin particles dispersed in the resin particle dispersion are composite particles containing components other than the resin particles, the dispersion in which these composite particles are dispersed can be prepared as follows. . For example, after dissolving and dispersing each component of the composite particles in a solvent, and dispersing in water together with a suitable dispersant as described above, and removing the solvent by heating or reducing the pressure, or a method obtained by emulsion polymerization, The latex can be prepared by a method in which mechanical shearing or electrical adsorption is performed on the surface of the latex produced by seed polymerization and immobilization is performed.
[0094]
The average particle size of the resin particles is desirably 1 μm or less, and more desirably in the range of 0.01 to 1 μm. When the average particle size of the resin particles exceeds 1 μm, the particle size distribution of the finally obtained toner for developing an electrostatic image is widened or free particles are generated, leading to a decrease in performance and reliability. On the other hand, when the average particle size of the resin particles is within the above range, there is no such a defect, the uneven distribution between toners is reduced, the dispersion in the toner is good, and the dispersion in performance and reliability is small. It is advantageous. The average particle size of the resin particles can be measured using, for example, a microtrack or the like.
[0095]
Examples of the coloring agent include carbon black, chrome yellow, Hansa yellow, benzidine yellow, slen yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliant carmine 3B, and brilliant carmine 6B. , DuPont Oil Red, Pyrazolone Red, Risor Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate Pigments;
[0096]
Acridine, xanthene, azo, benzoquinone, azine, anthraquinone, dioxazine, thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane And various dyes such as thiazine, thiazole, and xanthene dyes.
[0097]
These colorants may be used alone or in combination of at least two (two or more). In the latter case, the color of the toner can be arbitrarily adjusted by changing the type and the mixing ratio of the colorant (pigment). The colorant dispersion can be prepared, for example, by dispersing the colorant in an aqueous medium such as the surfactant.
[0098]
The average particle size of the colorant particles in the present invention is desirably 0.8 μm or less, and more desirably in the range of 0.05 to 0.5 μm. When the average particle size of the colorant particles exceeds 0.8 μm, the particle size distribution of the finally obtained toner for developing an electrostatic image is widened or free particles are generated, leading to a decrease in performance and reliability. When the average particle size of the colorant particles is smaller than 0.05 μm, not only the colorability in the toner is reduced, but also the shape controllability, which is one of the features of the emulsion aggregation method, is impaired, and a shape close to a true sphere is obtained. Can not be obtained.
[0099]
Further, the number% of particles having a particle diameter of 0.8 μm or more is preferably less than 10%, and substantially preferably 0%. The presence of such coarse particles impairs the stability of the agglomeration step and not only releases the coarse colored particles, but also broadens the particle size distribution. The particle number% of 0.05 μm or less is preferably 5 number% or less. The presence of such fine particles impairs the shape controllability in the fusion step, making it impossible to obtain smooth particles. On the other hand, when the average particle size, coarse particles, and fine particles of the colorant particles are within the above ranges, there is no such a defect, and uneven distribution between toners is reduced, and dispersion in the toner becomes good, and performance is improved. This is advantageous in that variations in reliability and reliability are reduced.
[0100]
The average particle size of the colorant particles can be measured using, for example, a microtrack or the like. The amount of the coloring agent is preferably set in a range of 1 to 20% by mass based on the toner particles.
[0101]
In the present invention, the colorant may be subjected to a surface modification treatment with rosin, a polymer, or the like.
The colorant that has been subjected to the surface modification treatment is sufficiently stabilized in the colorant dispersion, and after the colorant is dispersed to a desired average particle size in the colorant dispersion, the resin particles are dispersed. This is advantageous in that the colorants do not aggregate with each other even in the aggregation step when mixing with the liquid, and a good dispersion state can be maintained. On the other hand, the colorant that has undergone an excessive surface modification treatment may be released without being aggregated with the resin particles in the aggregation step. Therefore, the surface modification treatment is performed under optimal conditions selected as appropriate.
[0102]
Examples of the polymer include an acrylonitrile polymer and a methyl methacrylate polymer.
[0103]
As the conditions for the surface modification, generally, a polymerization method in which a monomer is polymerized in the presence of a colorant (pigment), a colorant (pigment) dispersed in a polymer solution to lower the solubility of the polymer, (Pigment) A phase separation method that precipitates on the surface can be used.
[0104]
The dispersion obtained by dispersing components (particles) such as the release agent and other internal additives includes, for example, an ionic surfactant, a polymer acid or a polymer when the other component is a release agent. It is dispersed in water together with a polymer electrolyte such as a base. This can be prepared by applying a strong shear to a fine particle of the release agent by using a homogenizer or a pressure discharge type disperser while heating the release agent at or above the melting point of the release agent. When the other components (particles) are inorganic particles or the like, they can be prepared by dispersing the inorganic particles or the like in an aqueous medium such as the surfactant.
[0105]
Examples of the release agent include polyethylene, polypropylene, low molecular weight polyolefins such as polybutene, silicones having a softening point upon heating, fatty acids such as oleamide, erucamide, ricinoleamide, and stearamide. Amides, carnauba wax, rice wax, candelilla wax, vegetable wax such as wood wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, fisher Minerals such as Tropsch wax, petroleum-based waxes, and modified products thereof can be used. One of these release agents may be used alone, or two or more thereof may be used in combination.
[0106]
The average particle diameter of the other components (particles) is desirably 1 μm or less, and more desirably in the range of 0.01 to 1 μm. If the average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner for developing an electrostatic image is widened or free particles are generated, which leads to a decrease in performance and reliability. On the other hand, when the average particle size of the resin particles is within the above range, there is no such a defect, the uneven distribution between toners is reduced, the dispersion in the toner is good, and the dispersion in performance and reliability is small. It is advantageous. The average particle size can be measured, for example, using a microtrack or the like.
[0107]
The dispersion medium in which the resin particle dispersion, the colorant dispersion and the other components (particles) are dispersed includes, for example, an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion-exchanged water, and alcohols. These may be used alone or in combination of two or more.
[0108]
The means for producing the various dispersions is not particularly limited, and examples thereof include known dispersion apparatuses such as a rotary shearing homogenizer, a ball mill having a media, a sand mill, and a dyno mill.
[0109]
In the present invention, various commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes comprising complexes of aluminum, iron, chromium and the like, and triphenylmethane pigments can be used as the charge control agent. However, a material that is difficult to dissolve in water is preferably used in view of control of ionic strength which affects coagulation and stability at the time of aggregation and reduction of wastewater contamination.
[0110]
When the charge control agent or the coagulant is added as described above, the group IA element (excluding hydrogen) and the group IIA in the fluorescent X-ray analysis, which is the condition (e) in the present invention, are used. It is necessary to control the addition amount so that the ratio of the element, the group IIIB element, and the group IVB element (excluding carbon) is in the range of 0.1 to 10%.
[0111]
In the present invention, it is preferable to add and mix a surfactant to the aqueous medium. Examples of the surfactant include anionic surfactants such as sulfate, sulfonate, phosphate, and soap; cationic surfactants such as amine salt and quaternary ammonium salt; polyethylene. Preferable examples include nonionic surfactants such as glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Of these, ionic surfactants are preferred, and anionic surfactants and cationic surfactants are more preferred.
[0112]
The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The surfactants may be used alone or in combination of two or more.
[0113]
Specific examples of the anionic surfactant include fatty acid soaps such as potassium laurate, sodium oleate, and castor oil sodium; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate, and nonylphenyl ether sulfate; lauryl sulfonate , Dodecyl sulfonate, dodecyl benzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate, etc. And other sulfonates; lauryl phosphate, isopropyl phosphate Phosphoric acid esters such as nonyl phenyl ether phosphate; dialkyl sodium sulfosuccinates, such as sodium dioctyl sulfosuccinate, sodium lauryl sulfosuccinate 2, polyoxyethylene sulfo sulfosuccinate salts such as succinic acid lauryl disodium; and the like.
[0114]
Specific examples of the cationic surfactant include amine salts such as laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, and stearylaminopropylamine acetate; lauryltrimethylammonium chloride, dilauryldimethylammonium Chloride, distearylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium ethosulfate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkylbenzenedimethyl Ammonium chloride, alkyl Quaternary ammonium salts such as ammonium chloride; and the like.
[0115]
Specific examples of the nonionic surfactant include alkyl ethers such as polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene octyl phenyl ether; Alkyl phenyl ethers such as oxyethylene nonylphenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, and polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxy Alkylamines such as ethylene oleyl amino ether, polyoxyethylene soybean amino ether and polyoxyethylene tallow amino ether; poly Alkyl amides such as xylethylene lauric amide, polyoxyethylene stearamide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether and polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearin Alkanolamides such as acid diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, and polyoxyethylene sorbitan monooleate And the like.
[0116]
In the present invention, a dispersion in which particles containing at least resin particles are dispersed is prepared by adding and mixing the resin particle dispersion or a dispersion of the colorant dispersion or other components thereto, and adding a dispersion of room temperature to room temperature. By heating in the range of the glass transition temperature of the resin, the resin particles and the colorant are aggregated to form aggregate particles. The volume average particle diameter of the aggregated fine particles is preferably in the range of 3 to 10 μm.
[0117]
When the resin particle dispersion and the colorant dispersion are mixed, the content of the resin particles may be 40% by mass or less, and preferably about 2 to 20% by mass. Further, the content of the colorant may be 50% by mass or less, and is preferably in the range of 2 to 40% by mass. Further, the content of the other components (particles) may be such that the object of the present invention is not impaired, and is generally extremely small, specifically, 0.01 to 5% by mass. In the range, preferably in the range of 0.5 to 2% by mass.
[0118]
In the electrostatic image developing toner used in the present invention, when the adhesion step is performed, the aggregated particles are used as base particles, and a coating layer of the fine particles (additional particles) is formed on the surface of the base particles. Having a structure of The layer of the fine particles (additional particles) may be a single layer or two or more layers. In general, the number of the layers is determined by the adhesion in the method for producing a toner for developing an electrostatic image of the present invention. This is the same as the number of times the process has been performed.
[0119]
Next, the mixed liquid containing the aggregated particles is subjected to heat treatment at a temperature equal to or higher than the softening point of the resin, generally in the range of 70 to 120 ° C. to fuse the aggregated particles, thereby forming a toner particle-containing liquid (toner particle dispersion). Obtainable.
[0120]
The obtained toner particle dispersion is separated into toner particles by centrifugation or suction filtration, and washed with ion-exchanged water 1 to 3 times. Thereafter, the toner particles are separated by filtration, washed 1-3 times with ion-exchanged water, and dried to obtain a toner for developing an electrostatic image used in the present invention.
[0121]
Further, the absolute value of the charge amount of the toner for developing an electrostatic image in the present invention is preferably in the range of 20 to 50 μC / g, and more preferably in the range of 25 to 40 μC / g. If the charge amount is less than 20 μC / g, background stains are likely to occur, and if it exceeds 50 μC / g, the image density tends to decrease. The ratio of the charge amount in summer and the charge amount in winter of the toner for developing an electrostatic image (summer charge amount / winter charge amount) is more preferably in a range of 0.7 to 1.3. If the ratio is out of the preferred range, the toner environment is strongly dependent and the charge stability is poor, which may be unfavorable in some cases.
[0122]
In the toner for developing an electrostatic charge image used in the present invention, the molecular weight distribution represented by the ratio (Mw / Mn) between the mass average molecular weight (Mw) and the number average molecular weight (Mn) measured using gel permeation chromatography is as follows: A range of 2 to 30 is preferable, and a range of 3 to 20 is more preferable. When the molecular weight distribution represented by the ratio (Mw / Mn) exceeds 30, the light transmittance and coloring properties are not sufficient, and especially when the toner for developing an electrostatic image is developed or fixed on a film, The image projected by transmission becomes an unclear and dark image or a projection image which does not develop color due to opacity, and if it is less than 2, the viscosity of the toner at the time of high-temperature fixing is remarkably reduced, and offset tends to occur. On the other hand, when the molecular weight distribution represented by the ratio (Mw / Mn) is within the above numerical range, the light transmittance and the coloring property are sufficient, and the viscosity of the electrostatic image developing toner at the time of high-temperature fixing decreases. Can be prevented, and the occurrence of offset can be effectively suppressed.
[0123]
The toner for developing an electrostatic image according to the present invention is excellent in various properties such as chargeability, developability, transferability, fixing property, and cleaning property, and cleaning property for a long time. In addition, since the various performances are stably exhibited and maintained without being affected by environmental conditions, the reliability is high. In addition, since the toner for developing an electrostatic image according to the present invention is manufactured by the above-described toner manufacturing method, the average particle size is small and the particle size distribution is sharp unlike the case where the toner is manufactured by the kneading and pulverizing method. It is.
[0124]
Furthermore, since the pigment particles in the toner have no coarse agglomerates and ions and fine particles are firmly bonded to the extent that they do not hinder the melting characteristics at the time of fixing, the charging member and the transfer member can be used for a long time. No pollution and no damage.
[0125]
Incidentally, the toner for developing an electrostatic image obtained by finally heating as described above, silica, alumina, titania, inorganic particles such as calcium carbonate and vinyl resin, polyester, resin fine particles such as silicone and the like. It can be used as a flow aid or a cleaning aid by adding it to the surface by applying a shearing force in a dry state. Examples of the inorganic particles include all particles usually used as an external additive on the surface of a toner, such as silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate, and cerium oxide.
[0126]
Examples of the organic particles include all particles usually used as an external additive on the surface of a toner, such as a vinyl resin, a polyester resin, and a silicone resin. In addition, these inorganic particles and organic particles can be used as a flow aid, a cleaning aid, and the like. Examples of the lubricant include fatty acid amides such as ethylenebisstearic acid amide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.
[0127]
The electrostatic image developer according to the invention is not particularly limited except that it contains the toner for developing an electrostatic image, and may have an appropriate component composition according to the purpose. For example, as the electrostatic image developer according to the invention, the electrostatic image developing toner may be used alone to prepare a one-component electrostatic image developer, or may be used in combination with a carrier. It may be prepared as a component-based electrostatic image developer.
[0128]
The carrier is not particularly limited and includes a carrier known per se, for example, a known carrier such as a resin-coated carrier described in JP-A-62-39879, JP-A-56-11461, and the like. A carrier can be used. The mixing ratio of the electrostatic image developing toner of the present invention and the carrier in the electrostatic image developer is not particularly limited, and can be appropriately selected depending on the purpose.
[0129]
The image forming method of the present invention includes a charging step, an electrostatic latent image forming step, and a toner image forming step, and may include a transfer step and a cleaning step. Each of the above steps is a general step itself, and is described in, for example, JP-A-56-40868 and JP-A-49-91231.
[0130]
The image forming method of the present invention can be carried out using an image forming apparatus such as a copying machine or a facsimile machine known per se.In the image forming method of the present invention, the charging roll and the transfer roll By combining the toners, the following effects, which are high in image quality and excellent in maintainability, can be expected.
[0131]
In other words, the toner according to the present invention has a small particle size distribution even though the volume average particle size D50v is in the range of 3 to 10 μm and is small in particle size such that the electrostatic characteristics cannot be controlled. Since the amount is small, contamination of the charging roll is small even after long-term image formation, and the charging property of the charging roll can be maintained for a long time. Furthermore, by combining the charging roll with a portion having good environmental resistance and stability and combining with a toner, it is possible to maintain a high-quality image for a long period of time.
[0132]
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the surface of the electrostatic latent image carrier. The toner image forming step is a step of developing the electrostatic latent image with a developer layer on a developer carrier to form a toner image. The developer layer is not particularly limited as long as it contains the toner for developing an electrostatic image of the present invention. The transfer step is a step of transferring the toner image to a transfer member surface. The cleaning step is a step of removing the electrostatic image developer remaining on the electrostatic latent image carrier.
[0133]
<Image forming apparatus>
Next, the image forming apparatus of the present invention will be described.
An image forming apparatus according to the present invention includes a charging unit that contacts a charging member to an electrostatic latent image carrier to apply a voltage from outside to perform charging, an electrostatic latent image forming unit that forms an electrostatic latent image, A toner image forming means for developing the electrostatic latent image using an electrostatic image developer, wherein the electrostatic image developer satisfies specific conditions described below. An image forming apparatus comprising an electrostatic image developing toner.
[0134]
FIG. 1 is a schematic sectional view showing an electrophotographic apparatus as an example of the image forming apparatus of the present invention. The electrophotographic apparatus shown in FIG. 1 includes an electrophotographic photosensitive member (electrostatic latent image carrier) 10, a charger (charging means) 11 for charging the surface of the electrophotographic photosensitive member 10, and a voltage applied to the charger 11. Power supply 12, an image input device (electrostatic latent image forming means) 13 for forming a latent image on the surface of the electrophotographic photosensitive member 10, and an electrostatic charge image developer formed on the surface of the electrophotographic photosensitive member 10. Developing device (developing device) 14 for developing the electrostatic latent image thus obtained to obtain a toner image, a transferring device (transfer device) 15 for transferring the formed toner image to the surface of the recording medium 20, and a specific cleaning blade. A cleaning device (cleaning means) 16 for removing residual toner and the like on the surface of the electrophotographic photosensitive member 10 by a certain blade 19, a static eliminator 17 for removing a residual potential on the surface of the electrophotographic photosensitive member 10, and transfer to the surface of the recording medium 20 Toner The image has a fixing device 18 for fixing by heat and / or pressure, etc., the.
[0135]
A charger 11 of a contact charging type such as a charging roll is disposed on the electrophotographic photoreceptor 10 in FIG. 1, and the charger 11 is operated by a voltage supplied from a power supply 12. In the present embodiment, as the transfer device 15, a contact transfer type such as a transfer roll is used. However, in the present invention, the contact transfer type and the non-contact transfer type are not limited.
The cleaning device 16 is provided with a blade 19 serving as the cleaning blade of the present invention at the opening of the box 21. Residual toner and the like removed from the surface of the electrophotographic photosensitive member 10 are stored in the box 21. The structure is
[0136]
In addition, the configurations of the image input unit (electrostatic latent image forming unit) 13, the developing unit (developing unit) 14, the transfer unit (transfer unit) 15, the static eliminator 17, and the fixing unit 18 are particularly limited in the present invention. Instead, any conventionally known configuration in the field of electrophotography can be applied as it is. In the case of using the contact charging type charger 11 as in this example, the static eliminator 17 is not necessarily provided.
[0137]
In the above-described image forming apparatus, by using the developer including the toner according to the present invention as the electrostatic image developer, various characteristics such as chargeability, developability, transferability, fixing property, and cleaning property are maintained for a long time. can do. In addition, since the various performances are stably exhibited and maintained without being affected by environmental conditions, the reliability is high. Furthermore, since the pigment particles in the toner have no coarse agglomerates and ions and fine particles are firmly bound to the extent that they do not hinder melting during fixing, the charging member and the transfer member can be contaminated even during long-term use. Thus, a high-quality image can be stably formed without causing any damage.
[0138]
【Example】
Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
First, the toner, charging roll, transfer roll, and the like used in Examples and Comparative Examples will be described.
[0139]
[Production of toner]
Various dispersions were prepared and toners were prepared as described below. The measurement of the physical properties of the resin fine particles, the toner and the like was performed by the following method.
-Measurement of molecular weight and molecular weight distribution-
The molecular weight and the molecular weight distribution were measured by gel permeation chromatography (GPC) using HLC-8120GPC and SC-8020 (manufactured by Tosoh Corporation) as measuring devices.
[0140]
-Particle size of dispersed fine particles-
Number average particle diameter D50n of the resin fine particles using a laser diffraction type particle size distribution analyzer (LA-700, manufactured by Horiba Ltd.) Was measured.
[0141]
−Glass transition temperature−
The measurement was performed at a heating rate of 10 ° C./min using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation).
[0142]
<Preparation of various dispersions>
(Resin particle dispersion)
・ Styrene (manufactured by Wako Pure Chemical Industries) 340 parts by mass
・ 60 parts by mass of n-butyl acrylate (manufactured by Wako Pure Chemical Industries)
・ 9 parts by mass of β-carboxyethyl acrylate (Rhodia Nichika)
-1'10-decanediol diacrylate (manufactured by Shin-Nakamura Chemical) 1.2 parts by mass
・ 2.7 parts by mass of dodecanethiol (made by Kao)
[0143]
The above materials were mixed and dissolved. This is added to a solution obtained by dissolving 4 parts by mass of an anionic surfactant (manufactured by Dow Chemical: Dowfax) in 550 parts by mass of ion-exchanged water, and dispersed and emulsified by mechanical stirring in a flask, and slowly stirred for 10 minutes. While stirring and mixing with the mixture, 50 parts by mass of ion-exchanged water in which 6 parts by mass of ammonium persulfate was dissolved were added. Next, after the system was sufficiently purged with nitrogen, the system was heated to 70 ° C. in an oil bath while stirring the flask, and emulsion polymerization was continued for 5 hours.
Thus, an anionic resin dispersion having a center diameter of 210 nm, a solid content of 43% by mass, a glass transition point of 51.0 ° C., and Mw of 35,000 was obtained.
[0144]
(Colorant particle dispersion)
-Colorant particle dispersion (1)-
-50 parts by mass of phthalocyanine pigment (manufactured by Dainichi Seika Co., Ltd .: PVFASTBLUE)
-Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts by mass
・ 240 parts by mass of ion exchange water
[0145]
After mixing each of the above materials and dispersing them for 10 minutes using a homogenizer (Ultra Turrax 750, manufactured by IKA), the mixture is dispersed by a circulation type ultrasonic disperser (RUS-600TCVP, manufactured by Nippon Seiki Seisaku-sho, Ltd.). (1) was prepared. The average particle size of the colorant in the obtained colorant dispersion liquid (1) was 150 nm, particles of 0.03 μm or less were 3.0% by number, and particles of 0.5 μm or more were 0.2% by number. .
[0146]
-Colorant particle dispersion (2)-
・ Carbon black (manufactured by CABOT: R330) 50 parts by mass
・ Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts by mass
・ 240 parts by mass of ion exchange water
[0147]
The above materials were mixed to prepare a colorant particle dispersion (2) under the same conditions as those for the colorant particle dispersion (1). The average particle size of the colorant in the obtained colorant dispersion liquid (2) was 155 nm, particles of 0.03 μm or less were 4.0% by number, and particles of 0.5 μm or more were 0.4% by number. .
[0148]
-Colorant particle dispersion (3)-
・ C. I. Pigment Red 122 (Dainichi Kagaku: ECR-185) 50 parts by mass
・ Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts by mass
・ 240 parts by mass of ion exchange water
[0149]
The above materials were mixed to prepare a colorant particle dispersion liquid (3) under the same conditions as for the colorant particle dispersion liquid (1). The average particle size of the colorant in the obtained colorant dispersion liquid (3) was 165 nm, particles of 0.03 μm or less were 5.0 number%, and particles of 0.5 μm or more were 0.4 number%. .
[0150]
-Colorant particle dispersion (4)-
・ C. I. Pigment Red 185 (manufactured by Clariant) 50 parts by mass
-Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts by mass
・ 240 parts by mass of ion exchange water
[0151]
The above materials were mixed to prepare a colorant particle dispersion (4) under the same conditions as those for the colorant particle dispersion (1). The average particle size of the colorant in the obtained colorant dispersion liquid (4) was 170 nm, particles of 0.03 μm or less were 6.0% by number, and particles of 0.5 μm or more were 0.3% by number. .
[0152]
-Colorant particle dispersion (5)-
・ C. I. Pigment Yellow 74 (manufactured by Clariant) 50 parts by mass
-Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) 10 parts by mass
・ 240 parts by mass of ion exchange water
[0153]
The above materials were mixed to prepare a colorant particle dispersion (5) under the same conditions as the colorant particle dispersion (1). The average particle size of the colorant in the obtained colorant dispersion liquid (5) was 175 nm, particles of 0.03 μm or less were 5.0% by number, and particles of 0.5 μm or more were 0.3% by number. .
[0154]
(Preparation of release agent dispersion)
50 parts by mass of polyethylene wax (Toyo Petrolite: PW725, melting point: 104 ° C)
・ 5 parts by mass of anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC)
・ 240 parts by mass of ion exchange water
[0155]
After mixing each of the above materials and dispersing them for 10 minutes using a homogenizer (Ultra Turrax 750 manufactured by IKA), dispersion treatment was performed with a pressure discharge type homogenizer to obtain a release agent dispersion having a center particle diameter of 200 nm. .
[0156]
<Preparation of toner particles>
(Toner particles 1)
・ 500 parts by mass of ion exchange water
・ Resin particle dispersion 200 parts by mass
-Colorant particle dispersion (1) 70 parts by mass
・ 70 parts by mass of release agent dispersion
・ Inorganic fine particle dispersion (Nissan Chemical Industries: Snowtex OL) 10 parts by mass
・ Inorganic fine particle dispersion liquid (Nissan Chemical Industries: Snowtex OS) 10 parts by mass
-2.0 parts by mass of metal salt flocculant (poly aluminum chloride manufactured by Asada Chemical Co., Ltd.)
[0157]
-Aggregation step-
The above-mentioned materials were mixed and dispersed in a round stainless steel flask with a homogenizer (IKA: Ultra Turrax T50). At the time of mixing, the liquid temperature was controlled at 25 ° C., and the resin particle dispersion, the colorant dispersion, and the release agent dispersion were divided and stepwise performed in three steps. Thereafter, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a volume average particle size D50v of 4.5 μm were formed. . Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.0 μm were formed.
[0158]
-Adhesion process-
To the obtained dispersion containing the aggregated particles, 60 parts by mass of the resin fine particle dispersion was slowly added, and the temperature of the oil bath for heating was further raised and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.6 μm.
[0159]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the liquid containing the obtained adhered particles so that the pH becomes 6.0, the stainless steel flask is closed, and stirring is continued using a magnetic force seal. After heating slowly to 60 ° C. and holding for 60 minutes, the mixture was heated to 96 ° C., and a 1 mol / L nitric acid aqueous solution was added until the pH reached 5.0, and the solution was held for 5 hours.
Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 1.
[0160]
(Toner particles 2)
The materials used were the same as in the preparation of the toner particles 1 except that the colorant dispersion (1) in the preparation of the toner particles 1 was changed to 60 parts by mass of the colorant dispersion (2).
[0161]
-Aggregation step-
The above-mentioned materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50 manufactured by IKA) while controlling the liquid temperature at 25 ° C. in the same manner as in the case of toner particles 1, and then heated in an oil bath. The flask was slowly heated to 40 ° C. while stirring, and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured using a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.8 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.2 μm were formed.
[0162]
-Adhesion process-
To the obtained dispersion containing the aggregated particles, 60 parts by mass of the resin fine particle dispersion was slowly added, and the temperature of the oil bath for heating was further raised and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.8 μm.
[0163]
-Fusion process-
A 1 mol / L aqueous solution of sodium hydroxide was added to the solution containing the adhered particles until the pH reached 6.0, then the stainless steel flask was sealed, and gently cooled to 85 ° C. while continuing to stir using a magnetic seal. After heating for 60 minutes, the mixture was heated to 96 ° C., and a 1 mol / L nitric acid aqueous solution was added until the pH reached 5.0, and the mixture was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 2.
[0164]
(Toner particles 3)
The materials used were the same as the toner particles except that the colorant dispersion (1) in the preparation of the toner particles 1 was changed to 40 parts by mass of the colorant dispersion (3) and 20 parts by mass of the colorant dispersion (4). No. 1 was manufactured.
[0165]
-Aggregation step-
The above materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50, manufactured by IKA) in the same manner as toner particles 1 while controlling the liquid temperature to 25 ° C., and then heated oil The flask was gently heated to 40 ° C. with stirring in a bath and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.7 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 4.9 μm were formed.
[0166]
-Adhesion process-
60 parts by mass of the resin particle dispersion was gradually added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was further increased and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.4 μm.
[0167]
-Fusion process-
After adding a 1 mol / L aqueous sodium hydroxide solution to the solution containing the adhered particles until the pH becomes 6.0, the stainless steel flask is sealed, and the mixture is stirred at 85 ° C. using a magnetic seal. After heating slowly to 60 ° C. and then heating to 96 ° C., a 1 mol / L nitric acid aqueous solution was added until the pH reached 5.0, and the solution was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 3.
[0168]
(Toner particles 4)
The materials used were the same as in the preparation of the toner particles 1 except that the colorant dispersion (1) in the preparation of the toner particles 1 was changed to 60 parts by mass of the colorant dispersion (5).
[0169]
-Aggregation step-
The above materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50, manufactured by IKA) in the same manner as toner particles 1 while controlling the liquid temperature to 25 ° C., and then heated oil The flask was gently heated to 40 ° C. with stirring in a bath and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.5 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 4.9 μm were formed.
[0170]
-Adhesion process-
60 parts by mass of the resin particle dispersion was gradually added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was further increased and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.3 μm.
[0171]
-Fusion process-
A 1 mol / L aqueous solution of sodium hydroxide was added to the solution containing the adhered particles until the pH reached 6.0, then the stainless steel flask was sealed, and gently cooled to 85 ° C. while continuing to stir using a magnetic seal. After heating for 60 minutes, a 1 mol / L nitric acid aqueous solution was added until the pH reached 5.0, heated to 96 ° C., and maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 4.
[0172]
(Toner particles 5)
Toner particles 5 were prepared in the same manner as in the preparation of toner particles 1 except that the fusing step was changed as described below.
[0173]
-Aggregation step-
In the case where the same material as used in the preparation of the toner particles 1 is used as the toner particles 1 in a round stainless steel flask while controlling the liquid temperature to 25 ° C., with a homogenizer (IKA: Ultra Turrax T50). After mixing and dispersing in the same manner as described above, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured using a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.6 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.1 μm were generated.
[0174]
-Adhesion process-
To the obtained dispersion containing the aggregated particles, 60 parts by mass of the resin fine particle dispersion was slowly added, and the temperature of the oil bath for heating was further raised and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.6 μm.
[0175]
-Fusion process-
After adding a 1 mol / L sodium hydroxide aqueous solution to the obtained liquid containing the attached particles until the pH becomes 7.0, the stainless steel flask is sealed, and the mixture is gently cooled to 85 ° C. while continuing to stir using a magnetic seal. After heating and holding for 60 minutes, it was heated to 96 ° C. and held for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum dryer to obtain toner particles 5.
[0176]
(Toner particles 6)
Toner particles 6 were prepared in the same manner as in the preparation of toner particles 1 except that the fusing step was changed as described below.
[0177]
-Aggregation step-
In the case where the same material as used for the production of the toner particles 1 is used as the toner particles 1 in a round stainless steel flask using a homogenizer (IKA: Ultra Turrax T50) while controlling the liquid temperature to 25 ° C. After mixing and dispersing in the same manner as described above, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.4 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.0 μm were generated.
[0178]
-Adhesion process-
To the obtained dispersion containing the aggregated particles, 60 parts by mass of the resin fine particle dispersion was slowly added, and the temperature of the oil bath for heating was further raised and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.6 μm.
[0179]
-Fusion process-
A 1 mol / L aqueous solution of sodium hydroxide was added to the solution containing the adhered particles until the pH reached 6.0, then the stainless steel flask was sealed, and gently cooled to 85 ° C. while continuing to stir using a magnetic seal. Then, the mixture was maintained at 60 ° C. for 60 minutes, and then a 1 mol / L nitric acid aqueous solution was added until the pH reached 4.0, heated to 96 ° C., and maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 6.
[0180]
(Toner particles 7)
Toner particles 1 were prepared in the same manner as in the preparation of toner particles 1 except that the metal salt coagulant was changed as described below.
[0181]
-Aggregation step-
Among the materials used for producing the toner particles 1, the metal salt coagulant was 2.0 parts by mass of magnesium chloride (hexahydrate, Shonan Wako Pure Chemical Industries, Ltd .: special grade), aluminum sulfate (14 to 18 hydrate) , Shonan Wako Pure Chemical Co., Ltd .: 1.0 parts by mass), using a homogenizer (IKA: Ultra Turrax T50) in a round stainless steel flask while controlling the liquid temperature to 25 ° C. After the toner particles 1 were mixed and dispersed in the same manner as in the case of the toner particles 1, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured using a Coulter counter (Multisizer 2 manufactured by Coulter Corporation), and it was confirmed that aggregated particles having a D50v of 4.4 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.0 μm were generated.
[0182]
-Adhesion process-
60 parts by mass of the resin particle dispersion was gradually added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was further increased and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.6 μm.
[0183]
-Fusion process-
A 1 mol / L aqueous solution of sodium hydroxide was added to the solution containing the adhered particles until the pH reached 6.0, then the stainless steel flask was sealed, and gently cooled to 85 ° C. while continuing to stir using a magnetic seal. Then, the mixture was maintained at 60 ° C. for 60 minutes, and then a 1 mol / L nitric acid aqueous solution was added until the pH reached 4.0, heated to 96 ° C., and maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum dryer to obtain toner particles 7.
[0184]
(Toner particles 8)
Toner particles 8 were prepared in the same manner as in the preparation of toner particles 1 except that the mixing and aggregation steps were changed as described below.
[0185]
-Aggregation step-
The same material as used in the production of the toner particles 1 was mixed and dispersed in a round stainless steel flask by controlling the liquid temperature at 25 ° C. with a homogenizer (IKA: Ultra Turrax T50), and then heated. The flask was gently heated to 45 ° C. with stirring in an oil bath for 60 minutes. Then, it heated to 55 degreeC. After holding at 55 ° C. for 2 hours, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 7.5 μm were formed. Further, the temperature of the heating oil bath was increased and maintained at 56 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 8.5 μm were formed.
[0186]
-Adhesion process-
60 parts by mass of the resin fine particle dispersion liquid (1) was slowly added to the dispersion liquid containing the aggregated particles, and the temperature of the oil bath for heating was further increased and maintained at 57 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 10.5 μm.
[0187]
-Fusion process-
A 1 mol / L aqueous solution of sodium hydroxide was added to the solution containing the adhered particles until the pH reached 6.0, then the stainless steel flask was sealed, and gently cooled to 85 ° C. while continuing to stir using a magnetic seal. After heating for 60 minutes, a 1 mol / L nitric acid aqueous solution was added until the pH reached 5.0, heated to 96 ° C., and maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum dryer to obtain toner particles 8.
[0188]
(Toner particles 9)
In the preparation of the toner particles 1, the ion-exchanged water was 800 parts by mass, and the coagulant was changed to 0.5 parts by mass of a cationic surfactant (Kanio B50, manufactured by Kao) instead of the metal salt coagulant. A toner particle 9 was produced in the same manner as in the production of the toner particle 1 except for the following changes.
[0189]
-Aggregation step-
The above materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50 manufactured by IKA) while controlling the liquid temperature at 30 ° C. in the same manner as in the case of toner particles 1, and then heated oil was heated. The flask was gently heated to 40 ° C. with stirring in a bath and held for 60 minutes. Then, it heated to 52 degreeC. After holding at 52 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.5 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 54 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 4.9 μm were generated.
[0190]
-Adhesion process-
60 parts by mass of the resin fine particle dispersion was slowly added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was raised and maintained at 55 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.5 μm.
[0191]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the solution containing the adhered particles until the pH reaches 6.0, the stainless steel flask is sealed, and heated to 96 ° C. while continuing to stir using a magnetic seal. 1 mol / L nitric acid was added until the pH reached 5.0, and the mixture was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 9.
[0192]
(Toner particles 10)
In the preparation of the toner particles 1, the toner particles 10 were prepared in the same manner as in the preparation of the toner particles 1, except that the pH in the fusion step was changed as follows.
[0193]
-Aggregation step-
When the same material as the material used in the production of the toner particles 1 is used as the toner particles 1 in a round stainless steel flask while controlling the liquid temperature to 30 ° C., using a homogenizer (IKA: Ultra Turrax T50). After mixing and dispersing in the same manner as described above, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.7 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.0 μm were generated.
[0194]
-Adhesion process-
60 parts by mass of the resin particle dispersion was slowly added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was further increased and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.7 μm.
[0195]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the solution containing the adhered particles until the pH becomes 8.0, the stainless steel flask is sealed, and heated to 96 ° C. while stirring with a magnetic seal. And maintained for 5 hours without pH adjustment. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 10.
[0196]
(Toner particles 11)
In the preparation of toner particles 1, toner particles 11 were prepared in the same manner as in the preparation of toner particles 1, except that the pH in the fusion step was changed as follows.
[0197]
-Aggregation step-
In a round stainless steel flask, a material similar to the material used for the production of the toner particles 1 was used with the homogenizer (IKA: Ultra Turrax T50) while controlling the liquid temperature to 30 ° C. Similarly, after mixing and dispersing, the flask was gently heated to 40 ° C. while being stirred in an oil bath for heating and held for 60 minutes. Then, it heated to 50 degreeC. After holding at 50 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.7 μm were formed. Further, the temperature of the heating oil bath was raised and kept at 52 ° C. for 1 hour. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.0 μm were formed.
[0198]
-Adhesion process-
To the obtained dispersion containing the aggregated particles, 60 parts by mass of the resin fine particle dispersion was slowly added, and the temperature of the oil bath for heating was further raised and kept at 54 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.6 μm.
[0199]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the solution containing the adhered particles until the pH becomes 6.0, the stainless steel flask is sealed, and the temperature is reduced to 96 ° C. while continuing to stir using a magnetic seal. The mixture was heated, 1 mol / L nitric acid was added until the pH became 3.5, and the mixture was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 11.
[0200]
(Toner particles 12)
In the preparation of the toner particles 1, the ion exchange water was changed to 800 parts by mass, and the coagulant was changed to 0.5 parts by mass of a cationic surfactant (Kanio B50 manufactured by Kao) instead of the metal salt coagulant. A toner particle 12 was produced in the same manner as the production of the toner particle 1 except that the process was changed as described below.
[0201]
-Aggregation step-
The above materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50 manufactured by IKA) while controlling the liquid temperature at 30 ° C. in the same manner as in the case of toner particles 1, and then heated oil was heated. The flask was rapidly heated to 50 ° C. with rapid stirring in a bath and held for 60 minutes. Then, it heated to 52 degreeC. After holding at 54 ° C. for 30 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 4.5 μm were formed. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 30 minutes. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 4.9 μm were generated.
[0202]
-Adhesion process-
60 parts by mass of the resin fine particle dispersion was slowly added to the obtained dispersion containing the aggregated particles, and the temperature of the oil bath for heating was raised and maintained at 55 ° C. for 1 hour. When the particle size of the obtained adhered particles was measured, D50v was 5.5 μm.
[0203]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the solution containing the adhered particles until the pH reaches 6.0, the stainless steel flask is sealed, and heated to 96 ° C. while continuing to stir using a magnetic seal. 1 mol / L nitric acid was added until the pH reached 5.0, and the mixture was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 12.
[0204]
(Toner particles 13)
In the preparation of the toner particles 1, the ion exchange water was changed to 800 parts by mass, and the coagulant was changed to 0.5 parts by mass of a cationic surfactant (Kanio B50 manufactured by Kao) instead of the metal salt coagulant. A toner particle 13 was produced in the same manner as in the production of the toner particle 1 except that the process was changed as described below and the attaching step was omitted.
[0205]
-Aggregation step-
The above materials were mixed and dispersed in a round stainless steel flask with a homogenizer (Ultra Turrax T50, manufactured by IKA) while controlling the liquid temperature to 40 ° C. in the same manner as in the case of toner particles 1, and then heated oil The flask was rapidly heated to 50 ° C. with rapid stirring in a bath and held for 60 minutes. Then, it heated to 52 degreeC. After maintaining at 54 ° C. for 60 minutes, the particle size was measured with a Coulter counter (manufactured by Coulter: Multisizer 2), and it was confirmed that aggregated particles having a D50v of 5.2 μm were formed. Further, the temperature of the heating oil bath was raised and maintained at 56 ° C. for 60 minutes. When the particle size was measured, it was confirmed that aggregated particles having a D50v of 5.7 μm were generated.
[0206]
-Fusion process-
After adding a 1 mol / L aqueous solution of sodium hydroxide to the solution containing the adhered particles until the pH reaches 6.0, the stainless steel flask is sealed, and heated to 96 ° C. while continuing to stir using a magnetic seal. 1 mol / L nitric acid was added until the pH reached 5.0, and the mixture was maintained for 5 hours. Thereafter, the mixture was cooled, filtered, washed five times with ion-exchanged water, and dried using a vacuum drier to obtain toner particles 13.
[0207]
[Evaluation of toner characteristics for electrostatic charge image development]
Each of the dried toner particles obtained as described above was evaluated for the following characteristics.
[0208]
-Particle size of toner, GSDv, GSDp-
The particle size (D50v) of the aggregated particles and the toner was confirmed with a Coulter counter (TAII manufactured by Nikkaki Co., Ltd.). GSDv, GSDp, etc. were determined from the obtained volume particle size distribution and number particle size distribution as described above. Further, the proportion of particles having a volume particle size distribution of at least twice D50v and the proportion of particles having a number particle size distribution of not more than 3/5 of D50n were determined.
[0209]
-Average circularity, average circularity standard deviation-
The average circularity (circular equivalent perimeter / perimeter) and circularity standard deviation were determined by a flow type particle size analyzer (FPIA-2000: manufactured by Sysmec Corporation).
[0210]
-Amount of coarse pigment particles in toner-
A cross-sectional photograph of the toner (transmission electron microscope, 5000 times) is taken into a Luzex image analyzer (Luzex FT, manufactured by Nireco), and the number% of pigment particle aggregates having a maximum length of 1 μm or more in one toner is analyzed by image analysis. The average value was obtained for 100 or more toners.
[0211]
-Quantitative analysis of elements in toner-
Using a fluorescent X-ray analyzer (XRF1800: manufactured by Shimadzu Corporation), the entire detection element in the toner was determined to be 100% by a fluorescent X-ray analysis method (XRF), and a Group IA element (excluding hydrogen) in all the elements measured ), The group IIA element, the group IIIB element, and the group IVB element (excluding carbon) were determined.
[0212]
-Surface wax exposure-
Using X-ray photoelectron spectroscopy (JPS-9000: manufactured by JEOL Ltd.), the amount of surface wax was quantified by C1S peak separation by X-ray photoelectron spectroscopy (XPS).
Table 1 shows the measurement results of the respective toner particles.
[0213]
[Table 1]

[0214]
[Manufacture of electrostatic image developer]
To 50 parts by mass of each of the obtained toner particles 1 to 13, 0.5 parts by mass of hydrophobic silica (TS720: manufactured by Cabot) was added and blended by a sample mill.
This blend was weighed to a ferrite carrier coated with 1% by mass of polymethyl methacrylate (manufactured by Soken Chemical Co., Ltd.) and having a volume average particle diameter of 50 μm so that the toner concentration became 5% by mass, and stirred with a ball mill for 5 minutes.・ Mixed to prepare Developers 1 to 13.
[0215]
[Preparation of charging roll]
A stainless steel shaft (diameter: 8 mm, length: 350 mm) was used as a conductive support, and a medium-resistance elastic layer was formed around the shaft by the following composition and processing method.
[0216]
100 parts by mass of GECO-based epichlorohydrin raw rubber (Epichroma CG102: manufactured by Daiso, composition ratio: epichlorohydrin 40 mol%, ethylene oxide 56 mol%, allyl glycidyl ether 4 mol%)
・ Calcium carbonate (Tamapearl TR-222H: Okutama Kogyo) 30 parts by mass
・ Sub (NeoFactis U-8: manufactured by Tenma Sub Kako) 10 parts by mass
・ 1.0 parts by mass of tetramethylammonium chloride (Nippon Resin: Elegance R115)
・ 0.5 parts by mass of stearic acid (fatty acid SA-200: manufactured by Asahi Denka)
・ Vulcanization accelerator (Noxera TT: Ouchi Shinko Chemical) 1.0 parts by mass
-1.5 parts by mass of vulcanization accelerator (Noxera DM: manufactured by Ouchi Shinko Chemical)
・ Vulcanization accelerator (Barnock R: manufactured by Ouchi Shinko Chemical) 1.0 part by mass
・ Vulcanizing agent (Sulfax: Tsurumi Chemical) 0.25 parts by mass
[0217]
After kneading the compound to form a compound having a uniform composition, a primary vulcanization (steam can, 4.5 × 10 5) was applied to the surface of the stainless steel shaft.^TwokPa, 150 ° C. × 1 hour), and secondary vulcanization (155 ° C. × 7 hours) to form a roller-shaped medium-resistance elastic body layer having an outer diameter of 14 mm and a length of 310 mm. The electric resistance of this medium resistance elastic layer is 2 × 10⁷Ω · cm, and the roller rubber hardness was 38 degrees (JIS A).
[0218]
Next, 80 parts by mass of a linear polyester resin (Vylon 30SS: manufactured by Toyobo Co., Ltd.) and 20 parts by mass of a melamine resin (Super Beckamine G-821-60: manufactured by Dainippon Ink Co., Ltd.) were mixed with conductive carbon. 5 parts by mass of FW200 (manufactured by Degussa) and 10 parts by mass of fluororesin fine powder (Lubron L-5: manufactured by Daikin Industries, Ltd.) were mixed and dispersed using a sand mill.
[0219]
Subsequently, the dispersion was diluted with xylene (a ratio of 150 parts by mass of xylene to 100 parts by mass of the dispersion) to prepare a coating material for forming a surface layer, and the viscosity was adjusted. After masking the shaft leaving a gap corresponding to the film thickness from a portion where the shaft and the end face of the elastic layer are in contact with each other, use a bell-type electrostatic coating machine (manufactured by Ransberg Industry Co.) to After a surface layer was formed on the entire surface of the elastic layer so that the film thickness when dried was 35 μm, the surface layer was dried at 160 ° C. for 30 minutes to produce a charging roll.
[0220]
With respect to this charging roll, the volume resistance was measured at an applied voltage of 100 V using a resistance measuring cell (trade name: 16008A, manufactured by YHP) and a resistance meter (trade name: R8340A, manufactured by Advantest). The sheet having a surface layer provided on the surface of the medium resistance elastic layer in the same manner as the roll (corresponding to the layer configuration of the charging roll) has a volume resistance of 10^5.2Ω · cm. The volume resistance of the surface layer is 10^4.5Ω · cm, and the difference in volume resistance between the charging roll and the surface layer was 0.7 digits. The voltage at which discharge breakdown occurred was measured and found to be 2200V. The surface coverage at this time was 95.6%. In addition, the said surface coverage was calculated using the following formula.
Surface coverage (%) = [(total surface area of surface layer) / (total surface area of charging roll)] × 100
[0221]
[Production of transfer roll]
A two-layer transfer roll was prepared as follows.
100 parts by mass of a rubber material (EPDM EP33: manufactured by Nippon Synthetic Rubber Co., Ltd.) containing 1 part by mass of sulfur as a vulcanizing agent and 0.6 part by mass of tetramethyltyrium disulfide as a vulcanization accelerator, Ketchien Black (Lion Aguso Co., Ltd., volume resistance ρv: 10^6.3Ωcm), 20 parts by mass of FT carbon (manufactured by Asahi Carbon Co., Ltd.), and 15 parts by mass of a foamed rubber compound having a composition of 6 parts by mass of benzenesulfonylhydrazide as a foaming agent, and the mixture was kneaded with a kneader and a roll mill. Kneaded.
[0222]
Next, the kneaded material was extruded into a tube shape by an extruder, and the extruded product was heated in a vulcanizer at a temperature of 126 ° C and a pressure of 1.5 kg / cm^TwoIt foamed by heating under the pressurized steam of G. A stainless steel shaft (diameter: 8 mm, length: 350 mm) is inserted into the obtained foamed elastic body, and a heat obtained by dispersing an ion-conductive polymer in polyvinylidene fluoride (PVDF) resin having a thickness of 0.1 mm. A transfer roll having a layer thickness of 5 mm was obtained by coating the shrink tube at 120 ° C.
[0223]
The hardness of the foamed elastic body (base layer) was 60 ° in Asker C hardness, and the roll hardness was 40 ° in Asker C hardness. The volume resistivity of the polyvinylidene fluoride (PVDF) is 10^8.2Ωcm, surface resistance is 10^7.5Ω / □. In addition, a PVDF tube in which an ionic conductive polymer is dispersed is prepared by mixing 40% by mass of Pelestat 6321 chips manufactured by Sanyo Chemical Industries, Ltd. with PVDF powder as an ionic conductive polymer and kneading the mixture with a twin screw extruder. The pellets are extruded while being stretched into a tube by a single screw extruder.
[0224]
<Example 1>
As an evaluation machine, a modified copier (Laser Wind 3310: manufactured by Fuji Xerox Co., Ltd.) was used, and the charging roll was installed so as to rotate in contact with the photoconductor. Only a 750 V DC power supply and a 2 kV 2 kHz AC power supply superimposed were applied. The transfer roll was also installed at the same time.
[0225]
The developer 1 was set as a developer in the developing device of the above copying machine, and a continuous running test of 4,000 sheets was continuously performed in an environment of 23 ° C. and 55% RH. The toner charge amount retention, image quality, paper releasability, transfer / charging roll contamination, image quality defects in transfer image quality (holographic characters, white spots at edges), etc. were evaluated.
[0226]
-Toner charge amount maintenance-
The toner charge amount at the initial stage and after the running test was measured by a charge amount measuring device TB200 (manufactured by Toshiba Corporation), and evaluated according to the following criteria.
[0227]
：: decrease in charge amount after running test is less than 5 μC / g
Δ: The decrease in charge amount after the running test is 5 μC / g or more and less than 10 μC / g.
×: Decrease in charge amount after running test is 10 μC / g or more
[0228]
-Image density-
After the running test, a solid image over the entire surface was output, and the image density uniformity was visually evaluated according to the following criteria.
：: No problem with uniform over the entire surface.
Δ: Density unevenness is observed.
X: The density has decreased overall.
[0229]
-Fogging-
The white background image after the running test was visually evaluated according to the following criteria.
：: No fog.
Δ: Slight fog is observed.
X: A considerable fogging was observed and a problem in quality was observed.
[0230]
−Granularity−
The halftone image after the running test was output and visually evaluated according to the following criteria.
：: No problem with uniform over the entire surface.
Δ: Some roughness is observed.
[0231]
-Transfer efficiency-
The transfer efficiency at the initial stage and after the running test was determined and evaluated according to the following criteria. The transfer efficiency was measured for the solid image by measuring the amount of toner per unit area (TMA) transferred to the recording paper and the amount of untransferred toner per unit area (DMA) remaining on the photoreceptor surface. It was calculated by the equation.
Transfer efficiency (%) = [(TMA) / (TMA + DMA)] × 100
[0232]
：: Transfer efficiency hardly decreases.
Δ: Transfer efficiency decreased by 5% or more and less than 10%.
D: Transfer efficiency decreased by 10% or more.
[0233]
-Hollow characters, white spots-
The fine line (English) image after the running test was visually evaluated according to the following criteria.
：: good
△: Minor occurrence
×: Generated
[0234]
−Dirt condition of roll−
After the running test, the charging roll and the transfer roll were removed, the toner adhering to the surface was transferred with a scotch tape, and evaluated visually by the following criteria.
Table 2 shows the above evaluation results.
[0235]
<Examples 2 to 7, Comparative Examples 1 to 6>
Examples 2 to 7 were carried out in the same manner as in Example 1 except that Developers 2 to 7 were used instead of Developer 1, respectively.
Further, Comparative Examples 1 to 6 were performed in the same manner as in Example 1 except that developers 8 to 13 were used instead of developer 1.
Table 2 summarizes the results.
[0236]
[Table 2]

[0237]
As shown in the results in Table 2, when the developer of the example was used, the toner chargeability and image quality were hardly affected, and the toner performance was stable. It turned out that there was no. On the other hand, when the developer of the comparative example was used, some problems occurred in the toner performance, the above-mentioned contamination, and the like. In particular, in Comparative Examples 3 to 6 having a large amount of coarse pigment particles, fogging, density unevenness, roll contamination, transfer efficiency reduction, and image defects due to a decrease in charge amount occurred, resulting in extremely poor results.
[0238]
【The invention's effect】
According to the present invention, there is provided an image forming method and an image forming apparatus which are excellent in environmental stability and repetition stability, have good charging performance and transfer performance, and can simultaneously satisfy high image quality and high reliability. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view illustrating an electrophotographic apparatus as an example of an image forming apparatus of the present invention.
[Explanation of symbols]
1 electrostatic latent image carrier
2 Cleaning blade
3 Holding member
10. Electrophotographic photosensitive member (electrostatic latent image carrier)
11 Charger (charging means)
12 Power supply
13 Image input device (electrostatic latent image forming means)
14 Developing device (developing means)
15 Transfer device (transfer means)
16 Cleaning device (cleaning means)
17 Static eliminator
18 Fixing unit
19 blade (cleaning blade)
20 Recorded object
21 box

Claims (2)

A charging step in which a charging member is brought into contact with an electrostatic latent image carrier to apply a voltage from outside to perform charging, an electrostatic latent image forming step in which an electrostatic latent image is formed, and an electrostatic latent image A toner image forming step of visualizing using an image developer, comprising:
An image forming method, wherein the electrostatic image developer contains an electrostatic image developing toner satisfying the following conditions (a), (b), (c), (d), and (e). Method.
(A) The volume average particle diameter D50v of the toner is in the range of 3 to 10 μm, and both the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are 1.25 or less.
(B) the particle size distribution index GSDp-under on the small particle size side is 1.27 or less, and the particle ratio of the particle size not more than 3/5 of the number average particle size D50n is 10 number% or less, and the volume average particle size is The ratio of particles having a particle diameter twice or more of D50v is 10% by volume or less.
(C) The average circularity is in the range of 0.940 to 0.980, and the average circularity standard deviation is 0.1 or less.
(D) The number of agglomerates of pigment particles having a maximum length of 1 μm or more, which is observed in a toner cross-sectional image observed by a transmission electron microscope, is 5% by number or less in one toner, and the pigment particles in the toner are Has an average dispersion diameter of 0.1 to 0.7 μm.
(E) Group IA element (excluding hydrogen), IIA element, IIIB element, and IVB element (carbon, assuming that the entire detection element intensity ratio by fluorescent X-ray analysis is 100%) ) Is in the range of 0.1 to 10%. Charging means for contacting the charging member with an electrostatic latent image carrier to apply a voltage from outside to perform charging; electrostatic latent image forming means for forming an electrostatic latent image; and electrostatic charging of the electrostatic latent image Toner image forming means for visualizing using an image developer, and an image forming apparatus,
An image forming method, wherein the electrostatic image developer contains an electrostatic image developing toner satisfying the following conditions (a), (b), (c), (d), and (e). apparatus.
(A) The volume average particle diameter D50v of the toner is in the range of 3 to 10 μm, and both the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are 1.25 or less.
(B) the particle size distribution index GSDp-under on the small particle size side is 1.27 or less, and the particle ratio of the particle size not more than 3/5 of the number average particle size D50n is 10 number% or less, and the volume average particle size is The ratio of particles having a particle diameter twice or more of D50v is 10% by volume or less.
(C) The average circularity is in the range of 0.940 to 0.980, and the average circularity standard deviation is 0.1 or less.
(D) The number of agglomerates of pigment particles having a maximum length of 1 μm or more, which is observed in a toner cross-sectional image observed by a transmission electron microscope, is 5% by number or less in one toner, and the pigment particles in the toner are Has an average dispersion diameter of 0.1 to 0.7 μm.
(E) Group IA element (excluding hydrogen), IIA element, IIIB element, and IVB element (carbon, assuming that the entire detection element intensity ratio by fluorescent X-ray analysis is 100%) ) Is in the range of 0.1 to 10%.

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