US3853552A - Method of fixing a toner by heating in electrophotographic duplication - Google Patents

Method of fixing a toner by heating in electrophotographic duplication Download PDF

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Publication number
US3853552A
US3853552A US00310155A US31015572A US3853552A US 3853552 A US3853552 A US 3853552A US 00310155 A US00310155 A US 00310155A US 31015572 A US31015572 A US 31015572A US 3853552 A US3853552 A US 3853552A
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United States
Prior art keywords
toner
temperature
heating
copy sheet
rollers
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Expired - Lifetime
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US00310155A
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English (en)
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R Namika
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Ricoh Co Ltd
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Ricoh Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/20—Fixing, e.g. by using heat
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/20—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat
    • G03G15/2003—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat
    • G03G15/2014—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat
    • G03G15/2064—Apparatus for electrographic processes using a charge pattern for fixing, e.g. by using heat using heat using contact heat combined with pressure
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S118/00—Coating apparatus
    • Y10S118/01—Anti-offset

Definitions

  • This invention relates to methods of fixing a toner by heating in electrographic duplication, and more particularly it is concerned with a method of fixing a toner adhering to a sheet of recording paper by heating at a temperature in a range from its secondary transition point to its melting point.
  • an electrostatic latent image of an original is formed on a sheet of recording paper, a toner is caused to adhere electrically to the electrostatic latent image, and the toner is fixed on the recording paper by heating.
  • this method of fixing a toner on the recording paper by heating it has hitherto been customary to pass the recording paper on which an electrostatic latent imageis formed between a pair of rollers which are heated, so that the toner is melted by the heat of the rollers and fixed on the recording paper.
  • This method of heating a toner by means of rollers to fix the same on recording paper has a disadvantage in that the offset phenomenon occurs or the molten toner adheres to the peripheral surfaces of the rollers and tends to adhere to and soil the sheets of recording paper which follow the preceding sheet of recording paper in movement between the rollers, thereby producing duplicates of the original which are unacceptable.
  • This invention has as its object the provision of a method of fixing a toner by heating in electrophotographic duplication whereby the toner adhering to a copy sheet such as a sheet of recording paper is fixed on the sheet by heating at a temperature in a range from its secondary transition point to its melting point.
  • the invention contemplates the steps of depositing a resinous toner on an image portion of a copy sheet and heating the toner to a temperature in a range between its secondary transition point and its melting point, for fixing the toner, while bringing the toner on the copy sheet into contact with a surface (e.g., a roller surface) for aiding in fixing the toner.
  • the heating and surface-contacting steps may, for example, comprise passing the copy sheet between a pair of rollers while heating at least one of the rollers for transfer of heat to the toner to raise the toner temperature into the stated range.
  • the rollers mayact to apply pressure to the toner on the copy sheet to aid in fixing the toner thereon.
  • the temperature of the toner does not exceed the stated range, for preventing transfer of toner by offset onto the roller surface.
  • heating of the toner to a temperature within the stated range effectively fixes the toner on the sheet, even though the toner is not heated above its melting point as in prior practice; and that fixing is thereby accomplished without offset, i.e., without pick-up of toner by the rollers.
  • a method of fixing a toner by heating in electrographic duplication which permits fixing of the toner on the recording paper to be accomplished by means of a simple inexpensive device without the fear of soiling the next following sheets of recording paper by the occurrence of the offset phenomenon and without requiring to provide the rollers with a protective coat or applying a liquid to the rollers.
  • FIG. ll is a diagram showing the characteristics of a toner in explanation of the behavior of the toner.
  • FIG. 2 is a sectional view of one form of apparatus adapted to carry the method according to this invention into practice.
  • a toner In electrophotographic duplication, an electrostatic latent image of an original is formed on a sheet of recording paper, a toner is caused electrically to adhere to the electrostatic latent image, and the toner is fixed on the recording paper by heating.
  • a toner mainly consists of a thermoplastic resin and carbon, and a plasticizer and other materials are added to reduce the melting point of the toner to a range from 45 to 120C.
  • a resin accounts for about to percent of the toner, so that the behavior of the toner is governed by the properties of the resin it contains. Accordingly, toners behave much the same as high molecular compounds.
  • FIG. I is a graph on which viscoelasticity is plotted against temperature in explanation of the behavior of a high molecular compound. It will be seen that the compound is converted from powder form into a glass transformation zone A at a secondary transition point at a first temperature Tg, from the glass transformation zone into a rubbery zone B at a higher temperature Tr, and from the rubbery zone into a fluid zone C at a still higher temperature Tm (the melting point temperature as the heating temperature rises. Generally, Tg is about one half to one third of Tm.
  • a range in the neighborhood of the secondary transition point is the softening temperature range for a high molecular compound or toner.
  • a high molecular compound or toner shows a marked change rapidly, and a change in temperature of 5 to 10C results in its modulus of elasticity increasing thousandfold, with the toner becoming as resilient as rubber.
  • the particles of the toner rarely undergo transformation at Tg; the toner tends to show visco elasticity and fluidity and the particles tend to be fused between Tr and Tm; and the particles become fluid beyond Tm. It will thus be seen that, by heating the toner in a range from Tg to Tm, it is possible to fix the toner without the occurrence of the offset phenomenon.
  • This invention resides in fixing the toner by heating at a temperature in a range from Tg to Tm.
  • Application of a suitable pressure to the toner particles at this time quickens the fusion of particles and at the same time causes the particles to begin to be bonded to one another as soon as they begin to soften.
  • the coefficient of viscosity of the toner is in a range of 10 to 10 P when its temperature is in a softening temperature range near the secondary transition point, so that the toner will become fluid in 1 to 10 seconds in this temperature range.
  • the coefficient of viscosity of the toner is in a range of 10 to 10 P when its temperature is in a softening temperature range near the secondary transition point, so that the toner will become fluid in 1 to 10 seconds in this temperature range.
  • the toner will be in contact with the heating rollers for 0.05 second. This makes it necessary to raise the surface temperature of the heating rollers above the secondary transition point temperature.
  • the toner is heated quickly, it will not become fluid because of time lag unless it is heated at a temperature higher than its melting point.
  • the offset phenomenon will not occur even if the temperature is set at a level near Tm.
  • the toner will adhere to the heating rollers owing to frictional charging taking place between the heating rollers and toner. That is, the toner particles are prevented from becoming viscous and the toner is attracted to the heating rollers with a greater force than it is attracted to the recording paper, so that the toner adheres to the rollers and the offset phenomenon occurs.
  • Fixing of the toner to the recording paper may be completed by virtue of the heat accumulated in the paper and the pressure applied to the paper after the recording paper has passed between the heating rollers. This is the case when the temperature for fixing the toner is set at a level near the secondary transition point. The temperature of the recording paper will be 50 to C about one second after it has passed between the heating rollers. The temperature for fixing the toner may also vary depending on the thickness of the recording paper.
  • FIG. 2 shows one embodiment of apparatus adapted to carry the invention into practice.
  • FIG. 2 there is shown a pair of heating rollers 1 and 2 maintained in engagement with each other.
  • the heating roller 11 consists of a heat resisting cylindrical roller 3 and a heater 5 disposed coaxially in the roller 3 while the heating roller 2 consists of a heat resisting cylindrical roller 4 and a heater 6 disposed coaxially in the roller 4, the rollers 3 and 4 being adapted to be driven by means for rotation individually or with the heaters 5 and 6.
  • a sheet of recording paper 8 to which a toner 7 adheres was fed between the pair of rollers l and 2 at a rate of 10 centimeters per second, and at the same time pressure was applied by pressing means between the heating rollers l and 2 so that a pressure of 5 kg might be applied to the recording paper 8 which is of A4 size according to the Japanese standards.
  • the surfaces of heating rollers 1 and 2 were heated to to C, the toner was fixed perfectly to the recording paper without causing the offset phenomenon to occur and a fixed image of high quality was produced.
  • the secondary transition point of the toner was 50C.
  • the heating rollers may be constructed such that each of them comprises a follower roller having a heater built therein, and a main roller which is heated by the heat emanating from the heater in the follower roller.
  • the heating rollers may be heater by heaters from outside the rollers instead of from inside the rollers.
  • An endless belt trained over a pair of rollers may sheet of recording paper between a pair of heating rol lers, said sheet of recording paper having a toner adhering to one surface thereof and coming into contact with one of said rollers, while heating the toner to a temperature in a range from its secondary transition point to its melting point so as to fix the toner on the recording paper, the temperature of said toner not being raised to the fluid zone, said one roller having a surface subject to pick-up of toner by offset.
  • a method of fixing a toner by heating in electrophotography comprising the steps of passing a sheet of recording paper between a heating roller and a rotary member maintained in engagement with each other and rotated in opposite directions, said sheet of recording paper having a toner adhering thereto and the toner adhering surface of the recording paper being brought into contact with the periphery of the heating roller, while heating the toner to a temperature in a range from its secondary transition point to its melting point, the temperature of said toner not being raised to the fluid zone.
  • Procedure according to claim 4, wherein the step of heating said toner comprises heating said surface for transfer of heat therefrom to said toner and said copy sheet for raising the temperature of the toner into said range.
  • Procedure according to claim 7, wherein the setp of heating said toner comprises heating at least one of said rollers for transfer of heat therefrom to said toner and said copy sheet for raising the temperature of the toner into said range.
  • the toner being in contact with a surface of one of the rollers, said one roller having a metal surface, while, heating at least one of the rollers for transfer of heat to the toner and the copy sheet to raise the toner temperature to a range between said first and second temperatures, for fixing said toner, the toner temperature being maintained not greater than said second temperature throughout contact of the toner with said roller surface for preventing offset of toner from said copy sheet to said roller surface, said temperature of said toner not being raised to the fluid zone, and while d. pressing said copy sheet between said rollers for applying pressure to the heated toner on the copy sheet to aid in fixing the toner.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fixing For Electrophotography (AREA)
  • Developing Agents For Electrophotography (AREA)
US00310155A 1971-12-03 1972-11-28 Method of fixing a toner by heating in electrophotographic duplication Expired - Lifetime US3853552A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP9805971A JPS5637549B2 (xx) 1971-12-03 1971-12-03

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US3853552A true US3853552A (en) 1974-12-10

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US (1) US3853552A (xx)
JP (1) JPS5637549B2 (xx)
DE (1) DE2257536B2 (xx)
GB (1) GB1409755A (xx)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4357404A (en) * 1979-06-04 1982-11-02 Fuji Photo Film Co., Ltd. Process for forming a lithographic printing plate by electrophotography
US5523190A (en) * 1989-07-28 1996-06-04 Canon Kabushiki Kaisha Magnetic toner and recording method
US20060222987A1 (en) * 2001-12-28 2006-10-05 Masanori Suzuki Image-forming color toner, developing agent, image-forming apparatus, toner container, image-forming process cartridge and image-forming process
US20080219717A1 (en) * 2007-03-05 2008-09-11 Shin Kayahara Transfer-fixing device, image forming apparatus, and transfer-fixing method

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5820033B2 (ja) * 1975-06-10 1983-04-21 キヤノン株式会社 定着装置
JPS5217826A (en) * 1975-06-27 1977-02-10 Fuji Xerox Co Ltd Temperature control device of contact heating fixing device
JPH0760287B2 (ja) * 1986-05-23 1995-06-28 三田工業株式会社 画像形成装置における定着方式
JPH01303470A (ja) * 1988-05-31 1989-12-07 Sharp Corp 複写機
US5157238A (en) * 1988-09-08 1992-10-20 Spectrum Sciences, B.V. Fusing apparatus and method
US5636349A (en) * 1988-09-08 1997-06-03 Indigo N.V. Method and apparatus for imaging using an intermediate transfer member
IL111846A0 (en) 1994-12-01 1995-03-15 Indigo Nv Imaging apparatus and intermediate transfer blanket therefor
US5023038A (en) * 1989-09-11 1991-06-11 Eastman Kodak Company Method and apparatus for texturizing toner image bearing receiving sheets and product produced thereby
US5815783A (en) * 1989-12-06 1998-09-29 Indigo N.V. Method and apparatus for printing on both sides of a substrate

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2870312A (en) * 1957-03-18 1959-01-20 Century Geophysical Corp Fixer for electrostatic photography
US3256002A (en) * 1963-12-23 1966-06-14 Xerox Corp Xerographic fixing device
US3364857A (en) * 1966-02-02 1968-01-23 Addressograph Multigraph Duplicating
US3600210A (en) * 1967-02-28 1971-08-17 Int Nickel Co Transparent xerocopies
US3682738A (en) * 1969-09-03 1972-08-08 Johnson & Johnson Methods and apparatus for depositing powdered materials in patterned areas
US3698314A (en) * 1970-06-15 1972-10-17 Owens Illinois Inc Method for image transfer
US3716018A (en) * 1969-10-09 1973-02-13 Ricoh Kk Device for heating and fixing toner images upon a recording medium

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2870312A (en) * 1957-03-18 1959-01-20 Century Geophysical Corp Fixer for electrostatic photography
US3256002A (en) * 1963-12-23 1966-06-14 Xerox Corp Xerographic fixing device
US3364857A (en) * 1966-02-02 1968-01-23 Addressograph Multigraph Duplicating
US3600210A (en) * 1967-02-28 1971-08-17 Int Nickel Co Transparent xerocopies
US3682738A (en) * 1969-09-03 1972-08-08 Johnson & Johnson Methods and apparatus for depositing powdered materials in patterned areas
US3716018A (en) * 1969-10-09 1973-02-13 Ricoh Kk Device for heating and fixing toner images upon a recording medium
US3698314A (en) * 1970-06-15 1972-10-17 Owens Illinois Inc Method for image transfer

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4357404A (en) * 1979-06-04 1982-11-02 Fuji Photo Film Co., Ltd. Process for forming a lithographic printing plate by electrophotography
US5523190A (en) * 1989-07-28 1996-06-04 Canon Kabushiki Kaisha Magnetic toner and recording method
US20060222987A1 (en) * 2001-12-28 2006-10-05 Masanori Suzuki Image-forming color toner, developing agent, image-forming apparatus, toner container, image-forming process cartridge and image-forming process
US20080219717A1 (en) * 2007-03-05 2008-09-11 Shin Kayahara Transfer-fixing device, image forming apparatus, and transfer-fixing method
US7907881B2 (en) * 2007-03-05 2011-03-15 Ricoh Company Limited Transfer-fixing device, image forming apparatus, and transfer-fixing method

Also Published As

Publication number Publication date
JPS5637549B2 (xx) 1981-09-01
DE2257536A1 (de) 1973-06-20
JPS4862438A (xx) 1973-08-31
DE2257536B2 (de) 1979-04-05
GB1409755A (en) 1975-10-15

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