EP0332105A2 - Dispositif de fixage et appareil d'enregistrement - Google Patents

Dispositif de fixage et appareil d'enregistrement Download PDF

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Publication number
EP0332105A2
EP0332105A2 EP89103889A EP89103889A EP0332105A2 EP 0332105 A2 EP0332105 A2 EP 0332105A2 EP 89103889 A EP89103889 A EP 89103889A EP 89103889 A EP89103889 A EP 89103889A EP 0332105 A2 EP0332105 A2 EP 0332105A2
Authority
EP
European Patent Office
Prior art keywords
fixing device
toner
formed product
roll
fixing
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.)
Withdrawn
Application number
EP89103889A
Other languages
German (de)
English (en)
Other versions
EP0332105A3 (fr
Inventor
Kiyohiko Tanno
Tadahiko Miyoshi
Masahisa Sobue
Yoshiyuki Yasutomi
Nobuyuki Yamashita
Hiroshi Nagase
Shoji Arimoto
Fumio Jooraku
Eiji Yasui
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP0332105A2 publication Critical patent/EP0332105A2/fr
Publication of EP0332105A3 publication Critical patent/EP0332105A3/fr
Withdrawn legal-status Critical Current

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    • 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
    • G03G15/2053—Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating
    • G03G15/2057—Structural details of heat elements, e.g. structure of roller or belt, eddy current, induction heating relating to the chemical composition of the heat element and layers thereof

Definitions

  • This invention relates to a fixing device of electrophotographic device, photo printer device, electrostatic recording device, magnetic recording device, and the like utilizing a composite ceramic prepared by forming a metallic silicon powder or ferro­silicon powder and thereafter heating and sintering the formed product in a nitrogenating atmosphere, as well as to a recording device of electrophotography, photo printer, electrostaic recording, magnetic recording and the like utilizing said fixing device.
  • a fixing device wherein an aluminum drum is coated with silicone, teflon or the like and an indirect heating is carried out from inside of this drum by the use of an instantaneous heater having a halogen lamp, a device proposed in the study titled: "Direct heating type ceramic roll for electrophotography” (preprint for the 59th Symposium of the Electrophotographic Society, pages 114-118, 1987) which comprises laminating a thick film of a material composed mainly of a ceramic on a metallic pipe, fusing it with plasma to form a resistor or an insulator, applying a current directly thereto to generate heat, and heating the drum directly by an insulating film provided thereon, etc.
  • the above-mentioned two techniques will be discussed below in more detail.
  • the former has the following disadvantage.
  • this technique is based on an indirect heating, and the light of halogen lamp leaks from the bearing part to the outer space which exercises an adverse influence on the photosensitive material, so that a particular consideration must be given to the structure and this complicates the device.
  • thickness of the aluminum drum cannot be too small for the reason of strength, due to which the drum has a high heat capacity and its build-up time for heat generation (thermal time constant) cannot be short.
  • the latter is also dis­advantageous in the following respect.
  • it may be somewhat improved in the thermal time constant, because it is of direct heating type.
  • this improvement cannot be sufficient, because the mother material is a metallic pipe.
  • its sutructure is compli­cated because it involves a laminated structure of plural layers of binding material, insulating material, resistor, etc.
  • a fixing drum is requested in the first place to have a small thermal time constant, i.e. a possi­bility of rapid heating.
  • a small thermal time constant i.e. a possi­bility of rapid heating.
  • it is requested to exhibit an even fixability and a good peelability from toner.
  • it In the third place, it must show a low heat loss and a high thermal efficiency.
  • it In the fourth place, it must not exert useless radiations or adverse physico-chemical influences upon the electrophotographic process. At the present stage, however, these requirements cannot be said to be fulfilled satisfactorily in various processes involving a toner-fixing process such as low speed, medium speed and high speed electrophotographic processes, toner processes, and the like.
  • the object of this invention consists in providing a novel fixing device which fulfils the above-­mentioned four requirements in that it has a low thermal time constant, a good peelability and a high thermal efficiency, exerts no adverse influence upon various processes involving a toner process such as various electrophotographic processes, photo printer recording processes, electrostatic recording processes, magnetic recording processes and the like, and has a sufficient lifetime at various process speeds, as well as a record­ing device to which said fixing device is applied.
  • This invention provides a fixing device for use in toner processes such as electrophotographic process and the like which comprises a thermal fixing roll used after transfer of toner, a compression bonding roll and a heat generating medium for said thermal fixing roll which is a composite ceramic prepared by adding an organic binder to a powder of metallic silicon or ferrosilicon, heating and kneading the resulting mixture, thereafter forming a formed product therefrom, removing the organic binder from the formed product at an elevated temperature, then heating and sintering the formed product in an atmosphere of nitrogenating gas and thereby connecting the particles of the insulating and electrodonductive particles of Si3N4, Si2N2O or SiO2 formed from the silicon and different in electrical resistivity from one another with whiskers formed from the above-mentioned silicon.
  • this invention also provides a fixing device for use in toner processes such as electrophoto­graphic process and the like which comprises a thermal fixing roll used after transfer of the toner, a compres­sion bonding roll and heat generating medium consist­ing of a first composite ceramic prepared by adding an organic binder to a powder of metallic silicon or ferro­silicon, heating and kneading the resulting mixture, forming the mixture into a formed product, removing the organic binder from the formed product at an elevated temperature and thereafter heating and sintering it in an atmosphere of nitrogenating gas to connect the parti­cles of the insulating and electroconductive particles of Si3N4, Si2N2O or SiO2 formed from the silicon and different in electrical resistivity from one another with whiskers formed from the silicon, and a second composite ceramic prepared by adding an organic binder to a powder of metallic silicon, ferrosilicon or other electroconductive compound different in electrical resistivity from the first composite ceramic, heating and kneading the resulting mixture, thereafter forming the mixture into a formed
  • this invention also provides a recording device for use in electrophotographic device, photo printer device, electrostatic recording device, magnetic recording device and the like to which the above-mentioned fixing device is applied.
  • the most important characteristic feature of this invention consists in using, as a heat generating medium of a fixing device, a composite ceramic prepared by adding an organic binder to a powder of metallic silicon or ferrosilicon, heating and kneading the resulting mixture, thereafter forming a formed product therefrom, removing the organic binder from the formed material at an elevated temperature, then sintering the formed product in an atmosphere of nitrogenating gas, and thereby connecting the particles of the insulating and electroconductive particles different from one another in electrical resistivity formed from the silicon such as Si3N4, Si2N2O and SiO2 with whiskers formed from the silicon.
  • the particles are heated and sintered in an atmosphere of nitrogenating gas, owing to which the whiskers formed from silicon powder connect the particles together and fill up the gaps between the particles and a 3-dimensional structure of the whiker grows in the sintered material.
  • a ceramic material having a high stiffness is obtained.
  • the dimensional change at the time of sintering this ceramic it as small as 0.13% or less, and a fixing structure unobtainable from prior ceramic materials can be obtained therefrom.
  • electroconductive particles may be linked together with Si3N4, if desired.
  • an electroconductive ceramic is obtained. If it is inte­grally sintered on the surface of the above-mentioned structure, it forms a good electro-conductive coating, and thereby a strong fixing coating is obtained.
  • the composite ceramic has a thermal expansion coefficient of 2.9 x 106/°C which is smaller than that of alumina (Al2O3) (8.8 x 106/°C (averaged in the range of 0°C to 1,000°C)). If the composite ceramic of this invention is used as a mother material of heat generat­ing medium, accordingly, it is resistant to a rapid rise in temperature and therefore the input power can be in­creased three times or more, expectedly.
  • the thermal time constant of temperature elevation can be shortened to 1/3.
  • the waiting time at the time of switching-on which has ranged from 20 seconds to one minute hitherto, can be shortened to about 7 to 20 seconds.
  • the heat generating medium of this invention can effectively heat the super­ficial conductive layer because its mother structure has a thermal diffusion coefficient of 9.77 x 106/°C which is much smaller than that of metals and therefore the heat does not diffuse into unnecessary parts.
  • an appropriate quantity of forming resin agent is added before the sintered material is produced in nitrogen atmosphere. Accordingly, when the conduction-treated film is formed, it is close to the state of porous plate retaining many minute pores and an excellent impregnation property.
  • the product can retain an affinity with the fixing demolding material such as oily substance, silicone, fluoride and the like.
  • the composite ceramic Si3N4-linked SiC which has been sintered in an atmosphere of nitrogenating gas is quite stable chemically and excellent in heat resist­ance and oxidation resistance. It undergoes no great quality change in itself and generates no substance harmful to the toner process. Further, it has no parti­cular high temperature part, and therefore emits no useless radiation flux.
  • the fixing device using this material can provide a fixing structure close to the ideal form hitherto considered.
  • this invention provides a fixing device wherein a composite ceramic prepared by adding, to the surface of the above-mentioned composite ceramic prepared by forming a powder of silicon or ferrosilicon and thereafter toner sintering the formed product in an atmosphere of nitrogenating gas (the first composite ceramic), a powder of metallic silicon, ferrosilicon or other conductive material different in electrical resistivity from the first ceramic and similarly forming and sintering it is used as a heat generator.
  • a composite ceramic prepared by adding, to the surface of the above-mentioned composite ceramic prepared by forming a powder of silicon or ferrosilicon and thereafter toner sintering the formed product in an atmosphere of nitrogenating gas (the first composite ceramic), a powder of metallic silicon, ferrosilicon or other conductive material different in electrical resistivity from the first ceramic and similarly forming and sintering it is used as a heat generator.
  • the content of electrodonductive particle in the sintered material used for the purpose of lowering the electrical resistivity of the sintered material is preferably 80% by volume or less. If its content exceeds 80% by volume, mecanical strength, thermal shock resistance and oxidation resistance of the ceramic are deteriorated.
  • Electrical resistivity of the sintered material can be varied arbitrarily by changing the content of the conductive particle in the sintered material in the range of 5 to 80% by volume.
  • resistivity of the sintered material can be varied arbitrarily in the range of 1014 ohm-cm to 10 ⁇ 5 ohm-cm.
  • the above-mentioned conductive particles or the above-mentioned insulating particles are linked together with at least one of Si3N4, Si2N2O and SiO2 formed from metallic silicon or ferrosilicon. It is small in volume change at the time of sintering and shows no deformation. Two layers different in electrical resistivity are linked together by Si3N4, Si2N2O or SiO2 formed from metallic silicon or ferrosilicon, and the bonding interface is excellent in heat resistance and thermal shock resistance similarly to its mother material.
  • Porosity of this sintered material is pre­ferably adjusted to 5 to 40%. If the porosity exceeds 40%, its mechanical strength becomes worse and it becomes more difficult to lower its resistivity. If its porosity is smaller than 5%, resistance to the permea­tion of nitrogenating gas or oxidative gas necessary for reacting the metallic silicon or ferrosilicon decreases, and it is difficult to obtain a good sintered product because, in order that the metallic silicon or ferro­silicon reacts with the nitrogenating gas or oxidative gas to form a phase of Si3N4, SiO2 or Si2N2O and combine the conductive compound or insulating compound thereto, the pores through which the gases can permeate are necessary.
  • the stress due to the difference in thermal expansion coefficient between the ceramic layers differ­ent in electrical resistivity can be relaxed and thereby the crack formation in the sintered material can be prevented.
  • Mean particle diameter of the metallic silicon or ferrosilicon is preferably adjusted to 5 ⁇ m or below because, if the mean particle diameter is greater than 5 ⁇ m, the time required for nitrogenation becomes longer and existence of residual silicon becomes noticeable.
  • thermoplastic resins such as polyvinyl butyral, polyethylene and the like or organosilicon type polymers such as silicon imide compound, polysilane compound and the like are used, for example.
  • the binder is added in a amount of 2 to 20% by weight, and relative density of the formed material is preferably adjusted to 60% or above.
  • the formed product is heated at least up to 1,350°C in an atmosphere of a nitrogenating, oxidative or oxidative-nitrogenating gas, such as bitrogen, ammonia, oxygen or the like (if desired, hydrogen, argon, helium, carbon monoxide and the like may be added thereto).
  • a nitrogenating, oxidative or oxidative-nitrogenating gas such as bitrogen, ammonia, oxygen or the like (if desired, hydrogen, argon, helium, carbon monoxide and the like may be added thereto).
  • metallic silicon ferrosilicon, insulating compound and conductive compound
  • those commercially available may be used as they are. More preferably, however, they are pulverized by means of a mill or the like to form them into round particles.
  • the whisker If a whisker is previously mixed and dispersed into starting material, the whisker cannot wholly be combined with the particles, but lumps of whisker or single whiskers remain between the particles of sintered product Contrariwise, in the composite material of this invention, the gaps between particles are filled by a number of nearly straightly crossing needle-like whiskers formed from the particles of formed product to link together the particles. Thus, the whiskers greatly contribute to thermal shock resistance and strength.
  • the gaps between the particles of insulating compound and conductive compound and/or whiskers are filled and 3-dimensionally combined by many whiskers formed from the silicon particles in the formed product, and there scarcely exist uncombined whiskers, owing to which a sintered product excellent in stiffness and high temperature strength can be obtained.
  • the mean particle diameters of the particles of the insulating and conductive compounds is preferably adjusted to 100 ⁇ m or below because, if the particle diameter exceeds 100 ⁇ m strength of sintered product decreases.
  • a ready-made whisker of insulating compound or conductive compound is used, its mean aspect ratio and length are preferably 2 to 50 and 0.2 to 100 ⁇ m, respectively. If its aspect ratio is smaller than 2 and its length is shorter than 0.2 ⁇ m, there is no effect as a whisker. If its aspect ratio is greater than 50 and its length is longer than 100 ⁇ m, the starting material becomes difficult to mix and poor in dispersibility.
  • non-oxidative conductive materials are used. They are nitrides, carbides, borides and silicides of elements belonging to Groups IIIa, Iva, Va, VIa and VIII.
  • TiN, TiC, TiB2, TiSi2, ZrN, ZrC, ZrB2, ZrSi2, HfN, HfC, TaN, TaC, TaB2, TaSi2, Mo2N, Mo2C, MoB, Cr2N, Cr3C2, CrB, CrSi2, NbN, NbC, NbSi2, VN, VC, WC and WSi2 are mainly used.
  • TiN, TiC, ZrN, ZrC, Cr2N and Cr3C2 are particularly preferable because of their excellent oxidation resistance.
  • silicides and borides are reactive with nitrogen in the nitrogenating gas, so that cracks are readily formed in the sintered product containing these conductive compounds, if the sintering time is not appropriate. Accordingly, the use of nitride and carbide is most desirable.
  • whisker formed from SiC particles not only whisker formed from SiC particles, but also whiskers as a starting material such as Si3N4, SiC and like may be used.
  • addition of too much an amount of whisker is undesirable, because it makes the product uneven in quality. Whiskers of insulating compound and conductive compound are also usable.
  • re-sinter a once sintered product for the purpose of making porosity of sintered product smaller than 5%.
  • a secondary sintering at ordinary pressure using a hot press, a hot static press or a sintering assistant is possible.
  • a highly heat-gener­ating composite ceramic is obtained because the whiskers are formed 3-dimensionally in the sintered material.
  • the difference in thermal expansion coefficient must be made as small as possible in order to minimize the possibility of crack formation.
  • a fixing device using a nitrogen-reacted ceramic or Si3N4-combined SiC sintered product It is an ideal fixing device in the point of evenly shortened build-up time of toner process, excellent peelability, improved thermal efficiency, and prevention from harmful radia­tions.
  • recording devices such as electrophotographic device, photo printer device, electrostatic recording device and magnetic recording device to which the fixing device of this invention is applied. In these recording devices, reduction of electric power consumption, improvement of the quality of recorded image and its stabilization can be achieved.
  • 1 Si3N4-combined SiC ceramic drum (that is, nitrogen-reacted combined ceramic drum)
  • 2 Si3N4-combined electroconductive ceramic
  • 3 is electricity-supplying slip ring for supplying electri­city.
  • the outer diameter of the both terminals is smaller than that of the central part.
  • An electroconductive ceramic 2 is attached to the terminal parts, and an external voltage can be applied thereto via slip ring 3.
  • Figure 2 illustrates another example of this invention, wherein constructions of 1, 2 and 3 are the same as in Figure 1.
  • This example is different from the above-mentioned one in that a permeative demolding oil is filled in the inner space of the drum.
  • the demolding oil having permeated the drum passes through the nitrogen-reacted ceramic to exude on the drum surface, where it exercises a demolding action on the toner fixation so as to leave no unnecessary sticking on the surface of fixing drum at the time of toner fixation.
  • the adhesion of toner onto the fixing drum occurring at the time of toner fixation is classified into cold offset taking place when the fixing temperature is too low and high temperature off­set taking place when the fixing temperature is too high. From the standpoint of fixation, a toner exhibit­ing a greater temperature difference between cold and hot offsets is considered a better toner.
  • the fixing drum of fine porous state is sufficiently impregnated with demolding agent similarly to usual impregnated bearings and used as a thermal fixing roll, a fixation free from toner offset can be continued without additional impregnation from inside or outside, so long as the state of impregnation is retained.
  • Figure 3 illustrates one example of this invention wherein a fixing drum prepared from the fixing structure of this invention is applied to a photo printer involving a toner process.
  • 1′ is photosensitive drum.
  • selenium, selenium-tellurium or organic photoelectric conductor (OPC) is used for this purpose.
  • charging device 2′ 3′ is positi­vely charged.
  • LED head 4′ a static image is formed.
  • Developing device 5 forms a developed toner image 7 by the use of toner 6 on the photosensitive body.
  • a recording paper is supplied from paper casette 8 by means of paper feeding roll 9, which is sent via paper guide 10 into transferring part 11, where a trans­ferred image is formed on recording paper 14.
  • 12 is thermally fixed by the fixing roll of Figure 1 or Figure 2 and compression bonding roll 13 to give a fixed toner 15.
  • Fixing roll 12 has a good offset characteristic and is free from unnecessary radiations, so that it can be formed into a relatively small-sized device. Since it has a high thermal efficiency, the total electric powder consumption of the device can be decreased.
  • the thermal time constant can be shortened. Since a reactive conductor is directly formed on a nickel-reacted ceramic, the heat generation is uniform and a demolding effect utilizing the adsorption of porous body and its permeation charac­teristic can sufficiently be exhibited. Thus, a good image is obtained, and a fixability of high thermal efficiency is obtained. Since the device of this inven­tion is almost free from unnecessary radiations and physicochemical actions, the restriction on the design of device can be lessened to a great extent.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Fixing For Electrophotography (AREA)
EP89103889A 1988-03-11 1989-03-06 Dispositif de fixage et appareil d'enregistrement Withdrawn EP0332105A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63056098A JP2515840B2 (ja) 1988-03-11 1988-03-11 熱定着装置
JP56098/88 1988-03-11

Publications (2)

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EP0332105A2 true EP0332105A2 (fr) 1989-09-13
EP0332105A3 EP0332105A3 (fr) 1990-05-30

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EP89103889A Withdrawn EP0332105A3 (fr) 1988-03-11 1989-03-06 Dispositif de fixage et appareil d'enregistrement

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997006118A1 (fr) * 1995-08-03 1997-02-20 Nimtz Guenter Materiau electroceramique a conductibilite electrique reglable
EP0761620A1 (fr) * 1995-08-28 1997-03-12 Kabushiki Kaisha Riken Rouleau chauffant et procédé pour sa fabrication

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5286950A (en) * 1991-03-26 1994-02-15 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Fixing device and heat roller therefor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3153661C2 (fr) * 1980-03-03 1993-01-28 Canon K.K., Tokio/Tokyo, Jp
JPS5816273A (ja) * 1981-07-21 1983-01-29 Canon Inc 定着装置
JPS6080884A (ja) * 1983-10-11 1985-05-08 Fuji Xerox Co Ltd 定着装置
JPS60118868A (ja) * 1983-11-30 1985-06-26 Ricoh Co Ltd 加熱定着装置
JPS60260077A (ja) * 1984-06-06 1985-12-23 Sumitomo Electric Ind Ltd 定着加熱ロ−ラ
JPS63132975U (fr) * 1987-02-20 1988-08-31

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997006118A1 (fr) * 1995-08-03 1997-02-20 Nimtz Guenter Materiau electroceramique a conductibilite electrique reglable
EP0761620A1 (fr) * 1995-08-28 1997-03-12 Kabushiki Kaisha Riken Rouleau chauffant et procédé pour sa fabrication

Also Published As

Publication number Publication date
JP2515840B2 (ja) 1996-07-10
JPH01231077A (ja) 1989-09-14
EP0332105A3 (fr) 1990-05-30

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