EP0360146B1 - Trägerteilchen für Entwicklungsverfahren elektrostatischer Bilder und Herstellungsverfahren - Google Patents

Trägerteilchen für Entwicklungsverfahren elektrostatischer Bilder und Herstellungsverfahren Download PDF

Info

Publication number
EP0360146B1
EP0360146B1 EP19890116985 EP89116985A EP0360146B1 EP 0360146 B1 EP0360146 B1 EP 0360146B1 EP 19890116985 EP19890116985 EP 19890116985 EP 89116985 A EP89116985 A EP 89116985A EP 0360146 B1 EP0360146 B1 EP 0360146B1
Authority
EP
European Patent Office
Prior art keywords
carrier
particles
magnetic material
resins
resin
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.)
Expired - Lifetime
Application number
EP19890116985
Other languages
English (en)
French (fr)
Other versions
EP0360146A3 (en
EP0360146A2 (de
Inventor
Kenji Tsujita
Shigenori Kouno
Yoshiaki Koizumi
Ken Ohmura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Konica Minolta Inc
Original Assignee
Konica Minolta Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Konica Minolta Inc filed Critical Konica Minolta Inc
Publication of EP0360146A2 publication Critical patent/EP0360146A2/de
Publication of EP0360146A3 publication Critical patent/EP0360146A3/en
Application granted granted Critical
Publication of EP0360146B1 publication Critical patent/EP0360146B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • G03G9/10—Developers with toner particles characterised by carrier particles
    • G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
    • G03G9/1132—Macromolecular components of coatings
    • 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
    • G03G9/10—Developers with toner particles characterised by carrier particles
    • G03G9/113—Developers with toner particles characterised by carrier particles having coatings applied thereto
    • G03G9/1131—Coating methods; Structure of coatings

Definitions

  • CMOS images referred as methods of developing the electrostatic latent image are wet developing and dry developing.
  • developers used in the latter dry developing are, in general, a one-component developer comprised of only a magnetic toner which comprises a toner containing a magnetic material, and a two-component developer comprised of a non-magnetic toner containing no magnetic material and a carrier having magnetic properties.
  • a coated carrier comprising magnetic particles whose surfaces are coated with a resin has been used with appreciation because of the possibility of improving the durability of carriers, frictional electrostatic charging performance and so forth.
  • the carrier particles may be mutually fused because of the solvent used, so that the carrier may have a large diameter, resulting in a great decrease in the yield of the carrier having the desired particle size distribution. It also requires a drying step, and also requires a reasonably long period of time for the manufacture of the carrier, bringing about the problem of a low productivity. The productivity may be further lowered with an increase in the coverage with resin and a decrease in the diameter of magnetic particles. To cope with this problem, the following countermeasures may be taken as a means for improving the productivity as a result of the shortening of time:
  • Still another problem is that part of starting materials scattered as a result of spraying does not participate in the formation of a layer, so that the starting materials are wasted and the materials which are nor coated electrostatically adhere in the form of powder to the surface of the carrier to give ill influences in carrying out the developing.
  • Another problem is that it takes much time for a cooling step since the surface of the core material is covered with the resin layer at temperatures close to the melting point or not lower than the melting point, and a disintegrating step is further required to loosen blocked coated carrier particles to separate them into unblocked carrier particles, resulting in a serious lowering of the production efficiency.
  • a third object of the present invention is to provide a carrier for electrostatic image development, that may generate less out-of-coating matters which do not contribute the coating, and hence can prevent difficulties caused by adhesion of the out-of-coating matters on the carrier surface as a result of their liberation.
  • a method of preparing a carrier for electrostatic image development comprising forming a uniform mixture comprised of magnetic material particles having a weight mean particle diameter of from 10 to 200 ⁇ m and resin particles having a weight mean particle diameter of less than 1/200 of that of said magnetic material particles, and repeatedly applying an impact force to said mixture in a mixing vessel having a material temperature set within the range of from 50 to 110°C, thereby coating said magnetic material particles with the resin material of said resin particles, the resin for the resin particles being defined in claim 1.
  • said magnetic material particles may preferably have a circularity of not less than 0.7.
  • the resin particles may also preferably have a BET specific surface area within the range of from 40 m2/g to 6,000 m2/g.
  • the carrier for electrostatic image development can be prepared through a simple means in a short time and yet in a high yield, and has a superior durability, exhibiting a stable frictional-electrostatic charging performance.
  • the carrier can be obtained according to dry coating, using the magnetic material particles and resin particles both having a specific particle diameter, so that;
  • the resin particles may be used in an amount of from 0.1 to 10 parts by weight, and preferably from 0.5 to 4 parts by weight, based on 100 parts by weight of the magnetic material particles.
  • the impact force applied to the mixture comprising the magnetic material particles and resin particles may be satisfactory if it is of the strength to the extent that the magnetic material particles are not crushed to powders.
  • the magnetic material particles As materials for the magnetic material particles, it is preferred to use substances capable of being strongly magnetized in the corresponding direction as a result of application of a magnetic field, as exemplified by metals such as iron, nickel and cobalt that show ferromagnetism, including iron, ferrites and magnetites, or alloys or compounds containing any of these metals.
  • metals such as iron, nickel and cobalt that show ferromagnetism, including iron, ferrites and magnetites, or alloys or compounds containing any of these metals.
  • the magnetic material particles may preferably have a circularity of not less than 0.7. Use of the magnetic material particles having such a high circularity brings about a high circularity also in the resulting coated carrier to increase the fluidity of the carrier. As a result, it becomes possible to steadily convey an appropriate quantity of toner to the developing space, so that a much superior development performance can be exhibited.
  • Circularity Peripheral length of a circle having the same area as the projected area of a particle Length of the contour of the projected image of the particle 2
  • This circularity can be measured, for example, with an image analyzer (a manufacture of Nippon Abionics Co.).
  • the weight mean particle diameter of the resin particles may be within the range of from 1/20,000 to 1/200, and preferably from 1/2,000 to 1/400, relative to that of the magnetic material particles. From a practical viewpoint, however, used are resin particles having a weight mean particle diameter of from 0.001 to 1 ⁇ m, and preferably from 0.01 to 0.15 ⁇ m, and a BET specific surface area of from 40 m2/g to 6,000 m2/g. A weight mean particle diameter more than 1.0 ⁇ m or a BET specific surface area of less than 40 m2/g, of the resin particles makes the resin particles spread with difficulty on the surface of the magnetic material particles, resulting in a difficulty in the coating treatment under dry conditions. A weight mean particle diameter less than 0.01 ⁇ m or a BET specific surface area more than 6,000 m2/g may worsen the dispersibility, sometimes making it impossible to achieve uniform coating, also sometimes resulting in a lowering of the yield.
  • the resin particles there can be used styrene resins, acrylic resins, styrene-acrylic resins, vinyl resins, ethylene resins, rosin modified resins, polyamide resins, polyester resins, silicone resins. and fluorine resins. These resins may be used in combination.
  • styrene-acrylic resins and acrylic resins can be particularly preferably used.
  • This styrene-acrylic resins are resins obtained by copolymerization of styrene monomers with acrylic monomers.
  • Specific examples of the styrene monomers may include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ⁇ -methylstyrene, p-ethylstyrene, 2,4-dimethystyrene, p-butylstyrene, p-t-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, p-dodecylstyrene, p-methoxyl
  • acrylic monomers may include, for example, acrylic acids or esters thereof such as acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, propyl acrylate, octyl acrylate, dodecyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, and methyl ⁇ -chloroacrylate; methacrylic acids or esters thereof such as methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, isobutyl methacrylate, octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phen
  • the styrene monomers and acrylic monomers may preferably be in a compositional ratio of from 9:1 to 1:9 in weight ratio.
  • the styrene component can afford to harden coating films and the acrylic component can afford to toughen coating films.
  • the amount of the electrostatic charging attributable to the toner in the frictional electrostatic charging between the coated carrier and toner can also be controlled to a considerable extent by appropriately varying the compositional ratio of these components.
  • the carrier may preferably have a weight mean particle diameter within an appropriate range corresponding with that of the magnetic material particles. That is to say, an excessively small weight mean particle diameter of the carrier tends to cause adhesion of the carrier on the photosensitive member, resulting in a deterioration of image quality. On the other hand, an excessively large weight mean particle diameter thereof results in a small specific surface area, so that it becomes difficult to achieve appropriate frictional electrostatic charging of the toner. It also becomes difficult for the carrier to be supported on the developer supporting member in a uniform state and also in a high density, resulting in a poor development performance.
  • the carrier it is preferable for the carrier to have a narrow particle size distribution.
  • the weight mean particle diameter ( r w) of the magnetic material particles is a value measured using "Microtruck, Type 7981-OX", manufactured by Lees & Northrup Co.; and the weight mean particle diameter ( r w) of the resin particles, measured using "Coulter, Model N4 Series", manufactured by Coulter Electronics Co.
  • the carrier for electrostatic image development according to the present invention can be prepared, for example, by the following procedure:
  • the magnetic material particles having a weight mean particle diameter of from 10 to 200 ⁇ m, and resin particles having a weight mean particle diameter of less than 1/200 of that of said magnetic material particles and a BET specific surface area within the range of not less than 40 m2/g are mixed and stirred using, for example, an ordinary stirring apparatus until they are uniformly mixed.
  • the resulting mixture is poured into, for example a high speed stirring mixing vessel or the like set to have a material temperature within the range of from 50 to 110°C, and an impact force is repeatedly applied to the above mixture for 10 to 60 minutes, and preferably 15 to 30 minutes.
  • the resin particles are spread and adhered on the surfaces of the magnetic material particles.
  • a coated carrier can be thus obtained.
  • an excessively high material temperature may make higher the adhesion of the resin particles, so that a phenomenon may be caused in which the particles of the resin particle powder are agglomerated each other into a mass and also the magnetic material particles may be combined through the resin particles to cause fusion. This makes it difficult to uniformly adhere the resin particles to the surfaces of the magnetic material particles.
  • Example 1 was repeated but the material temperature was controlled to be 45°C.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Developing Agents For Electrophotography (AREA)

Claims (6)

  1. Verfahren zur Herstellung eines Trägers für die Entwicklung eines elektrostatischen Bildes, umfassend magnetische Werkstoffteilchen, die durch Einwirkenlassen einer wiederholten Schlagkraft auf ein Gemisch aus magnetischen Werkstoffteilchen eines Gewichtsmittelteilchendurchmessers von 10 bis 200 µm und Harzteilchen eines Gewichtsmittelteilchendurchmessers von weniger als 1/200 desjenigen der magnetischen Werkstoffteilchen bei einer Materialtemperatur im Bereich von 50 bis 110°C mit Harzteilchen bedeckt wurden, wobei das Harz Styrolharze, Acrylharze, Styrol/Acryl-Harze, Vinylharze, Ethylenharze, Kolophonium-modifizierte Harze, Polyamidharze, Polyesterharze, Silikonharze und Fluorharze umfaßt.
  2. Verfahren zur Herstellung des Trägers nach Anspruch 1, wobei der Gewichtsmittelteilchendurchmesser des Harzteilchens im Bereich von 1/2000 bis weniger als 1/200 desjenigen der magnetischen Werkstoffteilchen liegt.
  3. Verfahren zur Herstellung des Trägers nach Anspruch 1, wobei die Kreisform der magnetischen Werkstoffteilchen nicht weniger als 0,7 beträgt.
  4. Verfahren zur Herstellung des Trägers nach Anspruch 1, durch 10 bis 60minütiges Einwirkenlassen einer wiederholten Schlagkraft auf das Gemisch bei einer Materialtemperatur im Bereich von 50 bis 110°C.
  5. Verfahren zur Herstellung des Trägers nach Anspruch 1, wobei die spezifische BET-Oberfläche der Harzteilchen 40 m²/g bis 6000 m²/g beträgt.
  6. Verfahren zur Herstellung des Trägers nach Anspruch 1, wobei das Gewichtsmischungsverhältnis magnetische Werkstoffteilchen 100/0,1 bis 10 beträgt.
EP19890116985 1988-09-22 1989-09-13 Trägerteilchen für Entwicklungsverfahren elektrostatischer Bilder und Herstellungsverfahren Expired - Lifetime EP0360146B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63239180A JP2709943B2 (ja) 1988-09-22 1988-09-22 静電像現像用キャリア及びその製造方法
JP239180/88 1988-09-22

Publications (3)

Publication Number Publication Date
EP0360146A2 EP0360146A2 (de) 1990-03-28
EP0360146A3 EP0360146A3 (en) 1990-06-20
EP0360146B1 true EP0360146B1 (de) 1994-11-09

Family

ID=17040914

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890116985 Expired - Lifetime EP0360146B1 (de) 1988-09-22 1989-09-13 Trägerteilchen für Entwicklungsverfahren elektrostatischer Bilder und Herstellungsverfahren

Country Status (3)

Country Link
EP (1) EP0360146B1 (de)
JP (1) JP2709943B2 (de)
DE (1) DE68919313T2 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5017258A (en) * 1986-06-20 1991-05-21 Shell Oil Company Pipe rehabilitation using epoxy resin composition
JP2843097B2 (ja) * 1990-03-20 1999-01-06 コニカ株式会社 静電荷像現像用キャリアの被覆用の樹脂粒子およびその製造方法
JP4887403B2 (ja) 2009-06-02 2012-02-29 シャープ株式会社 樹脂層被覆キャリアの製造方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE795370A (fr) * 1972-02-14 1973-05-29 Ibm Procede de fabrication de materiaux porteurs utilisables dans un appareil de reproduction electrophotographique
CA1140784A (en) * 1979-06-04 1983-02-08 Xerox Corporation Conductive powder coated electrostatographic carriers
JPS6337359A (ja) * 1986-08-01 1988-02-18 Minolta Camera Co Ltd 静電潜像現像用キヤリアの製造方法

Also Published As

Publication number Publication date
EP0360146A3 (en) 1990-06-20
JPH0287167A (ja) 1990-03-28
JP2709943B2 (ja) 1998-02-04
DE68919313T2 (de) 1995-04-06
DE68919313D1 (de) 1994-12-15
EP0360146A2 (de) 1990-03-28

Similar Documents

Publication Publication Date Title
US5955232A (en) Toners containing positively chargeable modified pigments
US4450221A (en) Encapsulated lyophilic magnetic particle and resin toner
EP0640884B1 (de) Ortho-benzoesäuresulphimid als Ladungssteuerungsmittel
JPS6057853A (ja) 圧力定着性カプセルトナ−
US5358815A (en) Toner compositions containing negative charge-controlling additive
EP0291930B1 (de) Entwickler für elektrostatische Ladungsbilder
EP0523733B1 (de) Entwicklerzusammensetzung für elektrostatische Ladungsbilder
EP0360146B1 (de) Trägerteilchen für Entwicklungsverfahren elektrostatischer Bilder und Herstellungsverfahren
JPH06230607A (ja) 静電潜像現像用イエローカラートナー
JPH11143118A (ja) 静電荷像現像用トナー及び画像形成方法
JPH028860A (ja) 静電像現像用キャリヤ
JPS63285555A (ja) 静電荷像現像用トナ−
JPH08101529A (ja) 磁性トナー及び画像形成方法
JPH07117766B2 (ja) 静電荷像現像用現像剤
JPH0213969A (ja) 静電像現像用キャリア
JP2707287B2 (ja) 静電像現像用キャリア及びその製造方法
JPS59187347A (ja) 磁性トナ−
US5194360A (en) Method of producing a carrier for electrostatic image developer
JP3729718B2 (ja) 静電荷像現像用トナーと画像形成方法
JPS59176752A (ja) 磁性トナ−
JPH0664361B2 (ja) 静電荷像現像用現像剤
JPH0287169A (ja) 静電像現像用キャリア及びその製造方法
JPS63235957A (ja) ２成分系現像剤
JPS61162054A (ja) 静電荷像現像用トナ−
JPH06194863A (ja) 現像剤

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): DE FR GB

17P Request for examination filed

Effective date: 19901206

17Q First examination report despatched

Effective date: 19930505

RBV Designated contracting states (corrected)

Designated state(s): DE GB

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB

REF Corresponds to:

Ref document number: 68919313

Country of ref document: DE

Date of ref document: 19941215

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19980907

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990913

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19990913

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20080926

Year of fee payment: 20