JPH021870A - Electrophotographic image forming method - Google Patents
Electrophotographic image forming methodInfo
- Publication number
- JPH021870A JPH021870A JP63143116A JP14311688A JPH021870A JP H021870 A JPH021870 A JP H021870A JP 63143116 A JP63143116 A JP 63143116A JP 14311688 A JP14311688 A JP 14311688A JP H021870 A JPH021870 A JP H021870A
- Authority
- JP
- Japan
- Prior art keywords
- toner
- image
- photoreceptor
- developer
- image forming
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 42
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000012546 transfer Methods 0.000 claims abstract description 35
- 230000002209 hydrophobic effect Effects 0.000 claims abstract description 15
- 108091008695 photoreceptors Proteins 0.000 claims description 40
- 239000000377 silicon dioxide Substances 0.000 claims description 15
- 230000001678 irradiating effect Effects 0.000 claims description 2
- 229910000859 α-Fe Inorganic materials 0.000 abstract description 6
- 238000005411 Van der Waals force Methods 0.000 abstract description 2
- 239000000853 adhesive Substances 0.000 abstract 1
- 230000001070 adhesive effect Effects 0.000 abstract 1
- 239000002245 particle Substances 0.000 description 16
- 206010047571 Visual impairment Diseases 0.000 description 15
- 238000002474 experimental method Methods 0.000 description 10
- 239000004973 liquid crystal related substance Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 6
- 239000000126 substance Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 229910009369 Zn Mg Inorganic materials 0.000 description 3
- 229910007573 Zn-Mg Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 230000003313 weakening effect Effects 0.000 description 2
- WZCQRUWWHSTZEM-UHFFFAOYSA-N 1,3-phenylenediamine Chemical group NC1=CC=CC(N)=C1 WZCQRUWWHSTZEM-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005513 bias potential Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000004720 fertilization Effects 0.000 description 1
- 125000001165 hydrophobic group Chemical group 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/097—Plasticisers; Charge controlling agents
- G03G9/09708—Inorganic compounds
- G03G9/09725—Silicon-oxides; Silicates
Abstract
Description
〔発明の技術分野〕
本発明は、乾式現像剤を用いる電子写真式画像形成方法
に関し、より詳細には、転写効率を略１００％に維持す
ることにより、単にクリーナを省略した簡単な画像形成
プロセスで良好な画像を安定的に得ることが可能な電子
写真式画像形成方法に関するものである。
〔従来技術〕
従来、電子写真プロセスを用いた画像形成装置で、感光
体ドラムを２回転させる間に用紙１枚分の画像形成を行
う所謂２回転１ページ方式が使用されているものがある
。この様な画像形成装置では、感光体ドラムの周囲に帯
電器、露光器、クリーナ兼現像器、転写器を順次配置し
、専用のクリーナを設けない所謂クリーナ無しプロセス
が採用されている。この場合、感光体の回転と共に、ま
ず帯電器により感光体表面に一様な帯電を施し、次に入
力情報に応じた光像を照射して情報に対応した静電潜像
を感光体表面に形成する。続いて、その静電潜像をクリ
ーナ兼現像器によってトナー像に顕像化し、この感光体
上のトナー像を転写器によって用紙上に転写する。転写
後、用紙は感光体から分離され定着等が施された後、機
外へ排出される。一方、転写を終えた感光体は更に回転
を続け、２回転目に入ってクリーナ兼現像器により感光
体上の残留トナーが除去される。斯様に、２回転１ペー
ジ方式では、感光体の２回転で１回の画像形成動作を行
う。
〔従来技術の問題点〕
しかしながら、上述の２回転１ページ方式によるクリー
ナ無し電子写真式画像形成方法においては、−度画像が
形成されたままで未清掃の感光体上に画像が形成される
ことによる残像の発生を防止する為、感光体の周長は使
用する最大サイズ用紙の長さよりも長くなければならな
い。例えば、最大用紙が８４版の場合は、その用紙長さ
が３６４ ＋＋ｍであるから、感光体の周長は３６４
ｍ−十余裕分の長さ（通常２５１程度）を必要とする。
その結果、直径が約１２０１の感光体ドラムを必要とし
、装置全体が大型化する。
又、上述のクリーナ無し電子写真式画像形成方法を用い
連続して画像形成を行う場合、用紙間の長さを感光体周
長以上に設定する必要があり、その分画像形成速度が遅
くなる。
そこで、」１記欠点を解消した方法、即ちクリーナを使
用せず且つ通常の小径感光体ドラムを用い１回転で用紙
１枚分の画像形成が可能な方式が、特開昭５４−１０９
８４２号公報及び特開昭６２−２２６１７３号公報等で
提案されている。然るに、これら２公報に開示された方
式は、何れも現像器を現像とクリーニングの両工程に兼
用すると共に同時に両工程を実施する為、現像器及びそ
れに関連する部位の構成が通常の電子写真プロセスより
複雑化することは否めない。
〔発明の目的〕
本発明は、上記従来技術の問題点に鑑みなされたもので
あり、通常の電子写真式画像形成方法から単にクリーナ
を省略しただけの簡単な構成の画像形成プロセスにより
、残像等の画質不良を発生させず良好な画像を安定的且
つ迅速に得ることが可能な電子写真式画像形成方法を提
供するこ七を目的とする。
〔発明の要点〕
本発明は、感光体表面を一様に帯電する工程と、一様帯
電させた感光体表面に画像情報に応じて光を照射し静電
潜像を形成する工程と、前記静電潜像を現像剤により顕
像化する現像工程と、前記顕像を転写器により用紙上に
転写する転写工程とから成る電子写真プロセスを備え、
転写されず前記感光体表面に残留する現像剤を除去せず
に前記電子写真プロセスを繰返し実施することにより画
像を得る電子写真式画像形成方法において、前記現像剤
に疎水性シリカを所定の割合で混合することを特徴とす
るものである。
〔発明の実施例〕
以下、本発明の実施例について添付の図面を参厨しなが
ら詳細に説明する。
本実施例は、本発明の電子写真式画像形成方法を液晶プ
リンタに適用した一実施例であり、第１図はその液晶プ
リンタの主要構成を示す模式図である。同図において、
液晶プリンタは、矢印方向に駆動回転可能に設けられた
感光体ドラム１と、その周辺に回転方向に沿って順次配
設され、上述の感光体ドラム１の周面１ａを所定電位に
均一に帯電する帯電器２、感光体ドラム周面１ａに露光
を行い入力情報に応じた静電潜像を形成する液晶記録ヘ
ッド３、静電潜像にトナーを付与して顕像化する現像器
４、現像されたトナー像を用紙ｐ上に転写する転写器５
から構成されている。尚、上述の帯電器２と転写器５に
は夫々所定極性（本例では帯電器２が一極性、転写器５
が子種性）のバイアス電１１１２２ａｌ ５ａが接続
され、感光体ドラム１側が接地されている。又、液晶記
録へラド３は、図示しない多数のマイクロシャッタが形
成された液晶シャッタパネル３ｂ、この液晶シャッタパ
ネル３ｂへ光を照射する光源３ａｘマイクロシヤツタを
透過した光を感光体ドラム周面１ａ上に結像させる結像
レンズアレイ３ｃで構成されている。
又、現像器４内には、感光体ドラム１に現像剤を付与す
る現像スリーブ４ａが配設され、この現像スリーブ４ａ
には現像バイアス電源４ｂが接続されている。
ここで、本発明の電子写真式画像形成方法につき、上述
の液晶プリンタに適用した例に従って説明する。
先ず、クリーナを省略する為には、未転写トナーを発生
させない、即ち転写効率を１００％に維持すればよいと
いう点に着目し、転写工程の作用メカニズムについて考
察する。
第２図に示す如く、感光体ドラム１に担持されたトナー
の内の感光体ドラム表面１ａに付着したトナーｔ、には
、大略、次の二通りの物理的付着力が作用している。
但し、ｈω： Ｌｌｆｓｈｌｔｚ−Ｖａｎ ｄｅｒ Ｗ
ａａｌｓ定数γ：定数−半径
Ｚ：トナーと感光体表面とのギヤ
ツブ
β：係数
ｑ：トナーの電荷
ε。：真空の誘電率
εｐ：感光体の比誘電率
今、γ＝５ （ｎｍ：ｌ ＋ Ｚ＝１ （ｎｍ）＋ β
＝２（Ｚ’ｑｌｎｍにおいて）、ｑ＝２８（：μｃ ／
ｇ ：ｌ ＋ε。＝ ８．８５４ Ｘ １０−１２（
ｑ２／Ｎ−ｌ１１”） ＊ ε２＝３゜４として、こ
れら各位を上記（１）、（２）式に代入すると、
Ｆ １： ８．４ Ｘ １０−３（ｄｙｎｅ）Ｆ ２：
０．９ Ｘ １０−’ （ｄｙｎｅ）となる。この計算
結果から、感光体表面１ａに接したトナーｔ１を感光体
表面に保持する力の約８８％がＶａｎ ｄｅｒ Ｗａａ
ｌｓ力Ｆ、であることが分る。尚、トナーａｔの個々の
トナー粒子は、現像器４中において所定の極性（本例で
は一極性）に摩擦帯電されている。
転写工程においては、上述の力Ｆ＋＋Ｆ２等により感光
体表面に担持されているトナーａｔに対し、転写器５か
ら用紙ｐの裏面に放電されたトナー粒子とは逆極性（本
例では子種性）のコロナイオンによるクーロン力Ｆ３が
逆方向（トナーｔを用紙に転移させる方向）に作用する
。従って、トナーｔＩが用紙ｐに転移する為には、
Ｆ３＞Ｆｌ＋Ｆ２・・・・・・・・・・・・・・・・・
・・・・・・・（３）でなければならない。上記（３）
式から、転写効率（現像に供されたトナー重量に対する
転写されたトナー重量の比率）を上げるには、左辺のＦ
３を大きくするか、右辺のＦ ＩＩ Ｆ ２を小さく
すればよいことがわかる。
上記クーロン力Ｆ３を大きくするには、転写器５に印加
する電圧を上げればよいが、過度に転写電圧を上げると
、転写コロナ電流が大きくなりすぎ、用紙ｐを突き抜け
て感光体ドラム１側に流れてしまう。その結果、トナー
層ｔはその極性が反転してコロナイオンと同極性となり
、逆にコロナ電流に沿った方向（感光体表面ｌａ側に引
き付けられる方向）の電界力を受け、用紙ｐ上にトナー
が転写されなくなる。従って、通常、転写電圧は上記（
３）式を充たす適度な大きさに設定されており、その場
合の転写効率は略８０％前後が限度で、略２０％の未転
写トナーが感光体ドラム表面１ａ上に残留することにな
り、クリーニン、グ工程が必要となる。
そこで、もう一方の方法、即ちトナー層ｔを感光体表面
に保持する力Ｆ ｌ＋ Ｆ Ｑの内の約８８％を占める
Ｖａｎ ｄｅｒ Ｗａａｌｓ力Ｆｌを小さくする方法に
着目する。
上記（１）式より明らかなように、Ｖａｎ ｄｅｒ Ｗ
ａａｌｓ力ＦＩは、Ｌｌｆｓｈｌｔｚ−Ｖａｎ ｄｅｒ
Ｗａａｌｓ定数ｈω。
トナー半径ｒ及び感光体表面とトナー間のギャップＺで
決定されるが、トナー半径ｒ及び感光体表面とトナー間
のギャップ２は、画像濃度等の画像品質面に及ぼす影響
が大きく、その面から決定される。従って、Ｖａｎ ｄ
ｅｒ Ｗａａｌｓ力Ｆ、を低下させるには、残るＬｌｆ
ｓｈｌｔｚ−ｖａｎ ｄｅｒ Ｗａａｌｓ定数ｈωを小
さくしなければならない。このＬｌｆｓｈｌｔｚ−Ｖａ
ｎ ｄｅｒＷａａ！ｓ定数ｈωは、感光体表面とトナー
との結合エネルギーに相当し、夫々の物質の表面自由エ
ネルギーに依存する値であり、トナーと感光体の場合は
、１，５乃至２．ＯｅＶとされている。このＬｌｆｓｈ
ｌｔｚ−ｖａｎ ｄｅｒ Ｗａａｌｓ定数ｈωを小さく
するには、トナーの表面自由エネルギーを小さくすれば
よいが、その為にはトナーの物質自体を変える必要があ
り、これは画像品質に多大な影響を及ぼすから適切では
ない。そこで、本発明では、表面自由エネルギーの小さ
い別物質の粒子をトナーと混合しく外添し）、それを感
光体表面とトナーとの間に介在させることにより、上記
ＬＩｆｓｈｌｔｚ４ａｎ ｄｅｒ Ｗａａｌｓ定数ｈω
を低下させることを企図する。
トナーに外添する粒子としては、それ自体の表面自由エ
ネルギーが小さい物質であるだけでなく、その物性が画
像品質に悪影響を及ぼさないことが要求される。本願発
明者等は、その様な用途に好適な外添粒子としてシリカ
（ＳｉＯｚ）粒子に着目し、種々の面から検討を行った
。以下、その検討結果について説明する。
シリカ粒子は、既に電子写真式画像形成プロセスにおけ
る現像剤にその流動性を向上させる為に添加されており
、現像剤外添用粒子として使用することに支障はない。
ところで、シリカ粒子に限らず物質の表面自由エネルギ
ーは、疎水化処理、即ち親水基を疎水基に置換すること
により変化することか知られている。そこで、本願発明
者等は、疎水化度の異なる種々のシリカ粒子を用いて転
写効率と疎水化度の関係を把握する実験を行った。
その実験方法と結果を以下に示す。[Technical Field of the Invention] The present invention relates to an electrophotographic image forming method using a dry developer, and more particularly, to a simple image forming process that simply omits a cleaner by maintaining transfer efficiency at approximately 100%. The present invention relates to an electrophotographic image forming method that can stably obtain good images. [Prior Art] Conventionally, some image forming apparatuses using an electrophotographic process use a so-called two-rotation, one-page method in which an image for one sheet of paper is formed while a photoreceptor drum rotates twice. In such an image forming apparatus, a so-called cleaner-less process is adopted in which a charger, an exposure device, a cleaner/developing device, and a transfer device are sequentially arranged around the photosensitive drum, and a dedicated cleaner is not provided. In this case, as the photoreceptor rotates, the surface of the photoreceptor is first uniformly charged by a charger, and then a light image corresponding to the input information is irradiated to create an electrostatic latent image corresponding to the information on the surface of the photoreceptor. Form. Subsequently, the electrostatic latent image is developed into a toner image by a cleaner/developing device, and the toner image on the photoreceptor is transferred onto a sheet of paper by a transfer device. After the transfer, the paper is separated from the photoreceptor, subjected to fixing, etc., and then discharged outside the machine. On the other hand, the photoreceptor that has completed the transfer continues to rotate, and in the second rotation, residual toner on the photoreceptor is removed by a cleaner/developing device. In this way, in the two-rotation, one-page method, one image forming operation is performed by two rotations of the photoreceptor. [Problems with the Prior Art] However, in the cleaner-less electrophotographic image forming method using the two-rotation, one-page method described above, the image is formed on an uncleaned photoconductor while the image is still formed. To prevent afterimages from occurring, the circumference of the photoreceptor must be longer than the length of the maximum size paper used. For example, if the maximum paper size is 84 plates, the length of the paper is 364 ++ m, so the circumference of the photoreceptor is 364 m.
m - requires a sufficient length (usually about 251). As a result, a photosensitive drum with a diameter of about 120 mm is required, making the entire device larger. Further, when images are formed continuously using the above-mentioned cleaner-less electrophotographic image forming method, it is necessary to set the length between sheets to be equal to or longer than the circumferential length of the photoreceptor, which slows down the image forming speed. Therefore, a method that eliminates the drawback mentioned above, namely, a method that does not use a cleaner and can form an image on one sheet of paper in one revolution using a normal small-diameter photoreceptor drum, was proposed in Japanese Patent Application Laid-Open No. 54-109.
This method has been proposed in Japanese Patent Application Laid-open No. 842 and Japanese Patent Application Laid-Open No. 62-226173. However, in both of the methods disclosed in these two publications, the developing device is used for both the developing and cleaning steps, and both steps are performed simultaneously, so the configuration of the developing device and its related parts is different from that of the normal electrophotographic process. It is undeniable that things will become more complicated. [Object of the Invention] The present invention has been made in view of the above-mentioned problems of the prior art, and uses a simple image forming process in which a cleaner is simply omitted from a normal electrophotographic image forming method, thereby eliminating afterimages and the like. An object of the present invention is to provide an electrophotographic image forming method capable of stably and quickly obtaining good images without causing image quality defects. [Summary of the Invention] The present invention includes a step of uniformly charging the surface of a photoreceptor, a step of irradiating the uniformly charged surface of the photoreceptor with light according to image information to form an electrostatic latent image, and a step of forming an electrostatic latent image on the uniformly charged surface of the photoreceptor. An electrophotographic process comprising a developing step of making an electrostatic latent image visible using a developer, and a transfer step of transferring the developed image onto paper using a transfer device,
In an electrophotographic image forming method in which an image is obtained by repeatedly performing the electrophotographic process without removing developer remaining on the surface of the photoreceptor without being transferred, hydrophobic silica is added to the developer in a predetermined ratio. It is characterized by being mixed. [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is an embodiment in which the electrophotographic image forming method of the present invention is applied to a liquid crystal printer, and FIG. 1 is a schematic diagram showing the main structure of the liquid crystal printer. In the same figure,
The liquid crystal printer includes a photoreceptor drum 1 that is rotatably driven in the direction of the arrow, and a photoreceptor drum 1 that is sequentially arranged around the photoreceptor drum 1 along the rotational direction, and that uniformly charges the circumferential surface 1a of the photoreceptor drum 1 to a predetermined potential. a charger 2 that exposes the circumferential surface 1a of the photoreceptor drum to form an electrostatic latent image according to input information; a developer 4 that applies toner to the electrostatic latent image to make it visible; A transfer device 5 that transfers the developed toner image onto the paper p
It consists of Note that the charger 2 and the transfer device 5 described above each have a predetermined polarity (in this example, the charger 2 has one polarity and the transfer device 5 has a predetermined polarity).
A bias voltage 11122al 5a (independent) is connected, and the photosensitive drum 1 side is grounded. In addition, the liquid crystal recording head 3 includes a liquid crystal shutter panel 3b on which a large number of microshutters (not shown) are formed, a light source 3ax that irradiates light to the liquid crystal shutter panel 3b, and the light transmitted through the microshutters to the photoreceptor drum peripheral surface 1a. It is composed of an imaging lens array 3c that forms an image on the lens. Further, a developing sleeve 4a for applying developer to the photoreceptor drum 1 is disposed in the developing device 4, and this developing sleeve 4a
A developing bias power supply 4b is connected to. Here, the electrophotographic image forming method of the present invention will be explained according to an example applied to the above-mentioned liquid crystal printer. First, the working mechanism of the transfer process will be considered, focusing on the fact that in order to omit the cleaner, it is sufficient to prevent the generation of untransferred toner, that is, to maintain the transfer efficiency at 100%. As shown in FIG. 2, roughly the following two types of physical adhesion forces act on the toner t attached to the photoreceptor drum surface 1a among the toners carried on the photoreceptor drum 1. However, hω: Llfshltz-Van der W
aals constant γ: constant-radius Z: gear angle β between toner and photoreceptor surface: coefficient q: charge ε of toner. : Permittivity of vacuum εp: Relative permittivity of photoreceptor Now, γ=5 (nm: l + Z=1 (nm) + β
= 2 (in Z'qlnm), q = 28 (: μc /
g:l+ε. = 8.854 x 10-12(
q2/N-l11'') * Assuming ε2=3°4 and substituting these values into the above equations (1) and (2), F 1: 8.4 X 10-3 (dyne) F 2:
0.9 x 10-' (dyne). From this calculation result, approximately 88% of the force that holds the toner t1 in contact with the photoreceptor surface 1a is due to Van der Waa.
It turns out that the ls force is F. Note that each toner particle of the toner at is triboelectrically charged to a predetermined polarity (unipolarity in this example) in the developing device 4. In the transfer process, the toner at, which is supported on the surface of the photoreceptor by the above-mentioned force F++F2, has a polarity opposite to that of the toner particles discharged from the transfer device 5 to the back surface of the paper p (in this example, fertilization). Coulomb force F3 due to the corona ions acts in the opposite direction (direction to transfer the toner t to the paper). Therefore, in order for toner tI to transfer to paper p, F3>Fl+F2...
It must be (3). Above (3)
From the equation, in order to increase the transfer efficiency (the ratio of the transferred toner weight to the toner weight used for development), the left side F
It can be seen that it is sufficient to increase 3 or to decrease F II F 2 on the right side. In order to increase the Coulomb force F3, it is sufficient to increase the voltage applied to the transfer device 5. However, if the transfer voltage is increased too much, the transfer corona current will become too large, penetrating the paper p and flowing toward the photoreceptor drum 1. It flows away. As a result, the polarity of the toner layer t is reversed and becomes the same polarity as the corona ions, and the toner layer t is subjected to an electric field force in the direction along the corona current (the direction in which it is attracted to the photoreceptor surface la side), and the toner layer t is transferred onto the paper p. will no longer be transcribed. Therefore, the transfer voltage is usually set as above (
3) It is set to an appropriate size that satisfies the formula, and in that case, the transfer efficiency is limited to approximately 80%, and approximately 20% of untransferred toner remains on the photoreceptor drum surface 1a. A cleaning process is required. Therefore, attention will be focused on the other method, that is, a method of reducing the Van der Waals force Fl, which accounts for about 88% of the force F l+F Q that holds the toner layer t on the surface of the photoreceptor. As is clear from the above equation (1), Van der W
aals force FI Llfshltz-Van der
Waals constant hω. It is determined by the toner radius r and the gap Z between the photoreceptor surface and the toner, but the toner radius r and the gap 2 between the photoreceptor surface and the toner have a large effect on image quality such as image density, and from that point of view It is determined. Therefore, Van d
To reduce the er Waals force F, the remaining Llf
The shltz-van der Waals constant hω must be made small. This Llfshltz-Va
n derWaa! The s constant hω corresponds to the binding energy between the surface of the photoreceptor and the toner, and is a value that depends on the surface free energy of each substance. It is said to be OeV. This Llfsh
In order to reduce the ltz-van der Waals constant hω, the surface free energy of the toner can be reduced, but this requires changing the toner substance itself, which has a significant impact on image quality. Not appropriate. Therefore, in the present invention, by externally adding particles of another substance with small surface free energy to the toner and interposing them between the photoreceptor surface and the toner, the above-mentioned LIfshltz4an der Waals constant hω is
The aim is to reduce the The particles externally added to the toner are required to not only have a small surface free energy, but also have physical properties that do not adversely affect image quality. The inventors of the present application focused on silica (SiOz) particles as external additive particles suitable for such uses, and conducted studies from various aspects. The results of this study will be explained below. Silica particles have already been added to developers in electrophotographic image forming processes in order to improve their fluidity, and there is no problem in using them as particles for external addition to developers. Incidentally, it is known that the surface free energy of not only silica particles but also substances can be changed by hydrophobization treatment, that is, by substituting hydrophilic groups with hydrophobic groups. Therefore, the inventors of the present application conducted experiments to understand the relationship between transfer efficiency and hydrophobicity using various silica particles having different degrees of hydrophobicity. The experimental method and results are shown below.
【実験例１】
（実験方法）
成分構成が、
フェライトキャリヤ・・・２２５ｍｆｆ１部”Ｎタイプ
トナー・・・・・・・・・ ２５重■部／リカ粒子・・
・・・・・・・０．１２５〜０．２５重量部（トナーに
対して０．５〜１．Ｏｗｔ％）＊Ｎタイプ：電子供与性
である二成分現像剤を用い、第１図に示すプリンタによ
り画像形成を行う。この場合、疎水化度の異なる４種類
のシリカ粒子とシリカ粒子を外添しないときの５通りに
ついて実験を行い、夫々の転写効率を調べる。尚、プリ
ンタの各電位設定は、
初期帯電電位ｖｓ・・・・・・・・・−４５０ｖ地肌部
電位ｖｌｌ・・・・・・・・・・・・−３００Ｖ現像バ
イアス電位ＶＢ・・・−２４０Ｖ露光部電位ｖＬ・・・
・・・・・・・・・ −２０Ｖとなっている。
（実験結果）
第１表
寧ワフカケミカルス°イーストアジア（株）製第１表の
結果から、疎水性シリカが転写効率をアップさせ、しか
もその疎水化度が上昇するに従い転写効率をよりアップ
させることがわかる。その理由は、疎水化処理によりシ
リカの表面自由エネルギーが低下する為と推察される。
これから、クリーナ無しプロセスを実施するに当り、疎
水化度の最も高いト２０００シリカを外添した現像剤を
用いれば、残像現象を発生させることなく良好な画像を
安定して得ることができることが判明した。
次に、上述の実験で最も高い転写効率を得たト２０００
シリカに着目し、これについて最適添加率を求めるべく
、添加率の異なる３種類の現像剤イ。
口、ハを調製し、これらについての検討実験を行なった
。その結果は次の通りである。[Experiment Example 1] (Experiment method) The composition of the ingredients is: Ferrite carrier...225 mff 1 part N type toner...25 mff parts/Lica particles...
......0.125 to 0.25 parts by weight (0.5 to 1.Owt% based on toner) *N type: Using an electron-donating two-component developer, as shown in Figure 1. Image formation is performed using the printer shown. In this case, experiments were conducted using four types of silica particles with different degrees of hydrophobicity and five cases in which no silica particles were externally added, and the transfer efficiency of each was examined. In addition, each potential setting of the printer is as follows: Initial charging potential vs......-450V Background potential Vll...-300V Development bias potential VB...- 240V exposed part potential vL...
...... It is -20V. (Experimental Results) Table 1 Ningwafuka Chemicals ° East Asia Co., Ltd. The results in Table 1 show that hydrophobic silica increases the transfer efficiency, and that as the degree of hydrophobicity increases, the transfer efficiency increases further. Recognize. The reason for this is presumed to be that the surface free energy of silica is reduced by the hydrophobization treatment. From this, it has been found that when carrying out a cleaner-free process, it is possible to stably obtain good images without causing image retention by using a developer to which To2000 silica, which has the highest degree of hydrophobicity, is externally added. did. Next, we will use the 2000 to
Focusing on silica, we developed three types of developers with different addition rates in order to find the optimal addition rate for silica. We prepared mouth and ha and conducted experiments to investigate them. The results are as follows.
【実験例２】
現像剤イの成分構成
フェライトキャリヤ
（粒径：５０μｍ、Ｃｕ−Ｚｎ−Ｍｇ系）−２２５重ｆ
ｆｉ！！ＩＫＮタイプトナー・・・・・・・・・・・・
・・・・・・ ２５重量部疎水性シリカ（１（−２００
０）・・・・・・０．１２５重量部（トナーに対して０
．５ｖｔ％）
上記現像剤を用いて実験例１と同方法により画像形成を
行ない、残像が発生する迄のプリント枚数を調べる。
結果は、１０００枚に至るまで残像は発生しなっかった
。[Experiment Example 2] Component composition of developer A Ferrite carrier (particle size: 50 μm, Cu-Zn-Mg system) - 225 F
Fi! ! IKN type toner・・・・・・・・・・・・
...... 25 parts by weight hydrophobic silica (1(-200
0)...0.125 parts by weight (0 for toner)
．． 5vt%) Images were formed using the above developer in the same manner as in Experimental Example 1, and the number of prints until an afterimage appeared was determined. As a result, no afterimage occurred until 1000 sheets were printed.
【実験例３】
現像剤口の成分構成
フェライトキャリヤ
（粒径：５０μｍ、Ｃｕ−Ｚｎ−Ｍｇ系）・２２５重量
部Ｎタイプトナー・・・・・・・・・・・・・・自・・
２５重量部疎水性シリカ（＋１−２０００）・・・・
・・０．１８８重量部（トナーに対して０．７５ｖｔ″
Ａ）
上記現像剤を用いて実験例１と同方法により画像形成を
行ない、残像が発生する迄のプリント枚数を調べる。
結果は、２５００枚に至るまで残像は発生しなっかうた
。[Experiment Example 3] Component composition of developer port Ferrite carrier (particle size: 50 μm, Cu-Zn-Mg type) 225 parts by weight N type toner... Self...
25 parts by weight hydrophobic silica (+1-2000)...
...0.188 parts by weight (0.75vt for toner)
A) Image formation is performed using the above developer in the same manner as in Experimental Example 1, and the number of prints until an afterimage occurs is determined. The results showed that no afterimages occurred until 2,500 sheets were printed.
【実験例４】
現像剤ハの成分構成
フェライトキャリヤ
（粒径：５０ｕ ｍ、Ｃｕ−Ｚｎ−Ｍｇ系）・２２５重
量部Ｎタイプトナー・・・・・・・・・・・・・旧・・
２５重量部疎水性シリカ（Ｈ−２０００）・・・・・
・ ０．２５重量部（トナーに対して］ 、Ｏｖｔ％）
上記現像剤を用いて実験例１と同方法により画像形成を
行ない、残像が発生する迄のプリント枚数を調べる。
結果は、４０００枚に至るまで残像は発生しなっかうた
。
以上の実験結果より、疎水化度が８０％のシリカ（１（
−２０００）を画像形成に悪影響を及ぼさない限度であ
るトナーに対して１．０ｗｔ％だけ外添した現像剤で、
クリーナ無しプロセスを実施すれば、約４０００枚のプ
リント枚数に至る迄残像が発生せず、充分実用に耐え得
ることが判明した。
上述した実験例４において、約４０００枚の連続プリン
トを終えた時点で残像が発生し始めるが、これは疎水性
シリカが繰返し使用される内に変質して表面自由エネル
ギーが変化し、前述した感光体表面とトナー粒子間のＶ
ａｎ ｄｅｒ Ｗａａｌｓ力Ｆｌを弱める効果が低下し
た為と考えられる。その原因として、フェライトキャリ
ヤの成分物質が疎水性シリカ粒子の表面に被着しシリカ
粒子同士が凝集してしまうことが考えられる。そこで、
疎水性シリカ粒子の寿命を延す為にキャリヤの種類を変
えて上記実験例と同様の画像形成実験を参考の為に行っ
てみたところ、以下の様な結果が得られた。[Experiment Example 4] Component composition of developer C: Ferrite carrier (particle size: 50 um, Cu-Zn-Mg system), 225 parts by weight N-type toner... Old...
25 parts by weight hydrophobic silica (H-2000)...
- 0.25 parts by weight (relative to toner, Ovt%) Images were formed using the above developer in the same manner as in Experimental Example 1, and the number of prints until an afterimage appeared was determined. The results showed that no afterimages occurred until 4,000 sheets were printed. From the above experimental results, silica with a degree of hydrophobicity of 80% (1 (
-2000) is externally added at 1.0 wt% to the toner, which is the limit that does not adversely affect image formation.
It has been found that if the cleaner-free process is carried out, no afterimages will occur until about 4000 prints are made, and the process is sufficiently practical. In Experimental Example 4 described above, afterimages begin to appear after approximately 4,000 continuous prints have been completed, but this is because the hydrophobic silica deteriorates as it is repeatedly used and its surface free energy changes, resulting in the above-mentioned photosensitive V between body surface and toner particles
This is thought to be because the effect of weakening the an der Waals force Fl has decreased. A possible cause of this is that the constituent substances of the ferrite carrier adhere to the surface of the hydrophobic silica particles, causing the silica particles to aggregate with each other. Therefore,
In order to extend the life of the hydrophobic silica particles, an image forming experiment similar to the above experimental example was conducted for reference by changing the type of carrier, and the following results were obtained.
【参考例１】
現像剤の成分構成
酸化鉄粉キャリヤ
（粒径：５０μｌ１１）・・・・・・・・・・・・・・
・２２５重量部Ｎタイプトナー・・・・・・・・・・・
・・・・・・・ ２５重量部疎水性シリカ（Ｈ−２００
０）・・・・・・ ０．２５重量部（トナーに対して１
．０ｗｔ％）
上記現像剤を用いて実験例１と同方法により画像形成を
行ない、残像が発生する迄のプリント枚数を調べる。
結果は、５０００枚に至るまで残像は発生しなっかうた
。[Reference Example 1] Component composition of developer Iron oxide powder carrier (particle size: 50μl11)
・225 parts by weight N type toner・・・・・・・・・・・・
...... 25 parts by weight hydrophobic silica (H-200
0)...0.25 parts by weight (1 part by weight for toner)
．． (0 wt%) Using the developer described above, images were formed in the same manner as in Experimental Example 1, and the number of prints until an afterimage occurred was determined. The results showed that no afterimages occurred until 5,000 sheets were printed.
【参考例２】
現像剤の成分構成
フェライトキャリヤ
（粒径：１０μｌ１１）・・・・・・・・・・・・・・
・２２５重１部Ｎタイプトナー・・・・・・・・・・・
・・・・・・・ ２５重量部疎水性シリカ（Ｈ−２００
０）・・・・・・ ０．２５重量部（トナーに対して１
．０１ｔ％）
上記現像剤を用いて実験例１と同方法により画像形成を
行ない、残像が発生する迄のプリント枚数を調べる。
結果は、５０００枚に至るまで残像は発生しなっかうた
。
上記参考例１．２の結果から、キャリヤ粒子物質の材質
や粒径を適切に選定することにより、疎水性シリカ粒子
の変質を抑制して１００％の転写効率をより長く持続さ
せることが可能であることが分った。
尚、本発明は上記の好適実施例に限定されるべきもので
はなく、本発明の技術的範囲において種々の変形が可能
であることは勿論である。例えば、現像剤は二成分磁性
現像剤に限らず、−成分若しくは非磁性の現像剤にも、
本発明は適用可能である。又、本発明は、液晶プリンタ
等の記録装置に限らず、電子写真複写機等の種々の電子
写真式画像形成装置に広く適用することができる。
〔発明の効果〕
以上、詳細に説明した如く、本発明によれば、トナーに
対して所定の割合で疎水性シリカ粒子を混合する（外添
する）ことにより、トナーと感光体表面間の付着力を弱
めトナーの用紙上への転写効率を略１００％に高めるこ
とができる。従って、通常の電子写真式画像形成方法か
ら単にクリーナを省略しただけの簡単な構成の画像形成
プロセスにより、残像等の画質不良の無い良好な画像を
安定的且つ迅速に得ることができる。そしてこれにより
、電子写真式画像形成装置の小型簡素化を大幅に促進す
ることが可能となる。[Reference Example 2] Component composition of developer Ferrite carrier (particle size: 10μl11)
・225 weight 1 part N type toner・・・・・・・・・・・・
...... 25 parts by weight hydrophobic silica (H-200
0)...0.25 parts by weight (1 part by weight for toner)
．． 01t%) Images were formed using the above developer in the same manner as in Experimental Example 1, and the number of prints until an afterimage appeared was determined. The results showed that no afterimages occurred until 5,000 sheets were printed. From the results of Reference Example 1.2 above, by appropriately selecting the material and particle size of the carrier particles, it is possible to suppress the deterioration of the hydrophobic silica particles and maintain 100% transfer efficiency for a longer period of time. I found out something. It should be noted that the present invention is not limited to the preferred embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention. For example, the developer is not limited to a two-component magnetic developer, but also a -component or non-magnetic developer.
The present invention is applicable. Further, the present invention is not limited to recording devices such as liquid crystal printers, but can be widely applied to various electrophotographic image forming devices such as electrophotographic copying machines. [Effects of the Invention] As described above in detail, according to the present invention, by mixing (externally adding) hydrophobic silica particles to the toner at a predetermined ratio, the adhesion between the toner and the photoreceptor surface is reduced. By weakening the adhesion force, it is possible to increase the transfer efficiency of toner onto paper to approximately 100%. Therefore, a good image free from image quality defects such as afterimages can be stably and quickly obtained by a simple image forming process in which a cleaner is simply omitted from a normal electrophotographic image forming method. As a result, it becomes possible to greatly promote the miniaturization and simplification of the electrophotographic image forming apparatus.
第１図は本発明の一実施例としての電子写真式画像形成
方法が適用される液晶プリンタの主要構成を示した模式
図、第２図は上記液晶プリンタにおける転写工程の動作
を示した模式的説明図である。FIG. 1 is a schematic diagram showing the main structure of a liquid crystal printer to which an electrophotographic image forming method as an embodiment of the present invention is applied, and FIG. 2 is a schematic diagram showing the operation of the transfer process in the liquid crystal printer. It is an explanatory diagram.
Claims (1)
感光体表面に画像情報に応じて光を照射し静電潜像を形
成する工程と、前記静電潜像を現像剤により顕像化する
現像工程と、前記顕像を転写器により用紙上に転写する
転写工程とから成る電子写真プロセスを備え、転写され
ず前記感光体表面に残留する現像剤を除去せずに前記電
子写真プロセスを繰返し実施することにより画像を得る
電子写真式画像形成方法において、前記現像剤に疎水性
シリカを所定の割合で混合することを特徴とする電子写
真式画像形成方法。A step of uniformly charging the surface of the photoconductor, a step of irradiating the uniformly charged surface of the photoconductor with light in accordance with image information to form an electrostatic latent image, and developing the electrostatic latent image with a developer. The electrophotographic process includes a developing step of forming an image, and a transfer step of transferring the developed image onto a sheet of paper using a transfer device, and the electrophotographic process can be performed without removing the developer remaining on the surface of the photoreceptor without being transferred. An electrophotographic image forming method in which an image is obtained by repeatedly carrying out a process, characterized in that hydrophobic silica is mixed into the developer at a predetermined ratio.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63143116A JPH021870A (en) | 1988-06-10 | 1988-06-10 | Electrophotographic image forming method |
| US07/361,594 US5073468A (en) | 1988-06-10 | 1989-06-05 | Method of forming electrophotographic image |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63143116A JPH021870A (en) | 1988-06-10 | 1988-06-10 | Electrophotographic image forming method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH021870A true JPH021870A (en) | 1990-01-08 |
Family
ID=15331289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63143116A Pending JPH021870A (en) | 1988-06-10 | 1988-06-10 | Electrophotographic image forming method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH021870A (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5422214A (en) * | 1992-02-14 | 1995-06-06 | Fuji Xerox Co., Ltd. | Dry toner for developing electrostatic latent image, process for producing same, and image formation process using same |
| US5826142A (en) * | 1996-01-09 | 1998-10-20 | Fuji Xerox, Ltd. | Image forming apparatus and electrophotographic photosensitive member to be used therefor |
| JPH1152610A (en) * | 1997-08-08 | 1999-02-26 | Fuji Xerox Co Ltd | Image forming method and electrostatic latent image developer |
| US6231402B1 (en) | 1998-04-14 | 2001-05-15 | Nec Corporation | Press-in contact and manufacturing method thereof |
| US6468707B1 (en) | 1999-07-06 | 2002-10-22 | Fuji Xerox Co., Ltd. | Image-forming process and image-forming apparatus |
| US6555282B2 (en) | 2000-09-27 | 2003-04-29 | Fuji Xerox Co., Ltd. | Toner for developing electrostatic latent image, image forming method and image forming apparatus using the same |
| US6589700B2 (en) | 2000-11-24 | 2003-07-08 | Fuji Xerox Co., Ltd. | Image carrier and apparatus and method for recording image using image carrier |
| US6650853B1 (en) | 1995-11-27 | 2003-11-18 | Fuji Xerox Co., Ltd. | Image recording apparatus and method with improved image transfer characteristics |
-
1988
- 1988-06-10 JP JP63143116A patent/JPH021870A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5422214A (en) * | 1992-02-14 | 1995-06-06 | Fuji Xerox Co., Ltd. | Dry toner for developing electrostatic latent image, process for producing same, and image formation process using same |
| US6650853B1 (en) | 1995-11-27 | 2003-11-18 | Fuji Xerox Co., Ltd. | Image recording apparatus and method with improved image transfer characteristics |
| US5826142A (en) * | 1996-01-09 | 1998-10-20 | Fuji Xerox, Ltd. | Image forming apparatus and electrophotographic photosensitive member to be used therefor |
| JPH1152610A (en) * | 1997-08-08 | 1999-02-26 | Fuji Xerox Co Ltd | Image forming method and electrostatic latent image developer |
| US6231402B1 (en) | 1998-04-14 | 2001-05-15 | Nec Corporation | Press-in contact and manufacturing method thereof |
| US6468707B1 (en) | 1999-07-06 | 2002-10-22 | Fuji Xerox Co., Ltd. | Image-forming process and image-forming apparatus |
| US6555282B2 (en) | 2000-09-27 | 2003-04-29 | Fuji Xerox Co., Ltd. | Toner for developing electrostatic latent image, image forming method and image forming apparatus using the same |
| US6589700B2 (en) | 2000-11-24 | 2003-07-08 | Fuji Xerox Co., Ltd. | Image carrier and apparatus and method for recording image using image carrier |
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