EP0441351A2 - Bilderzeugungsvorrichtung - Google Patents

Bilderzeugungsvorrichtung Download PDF

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Publication number
EP0441351A2
EP0441351A2 EP91101618A EP91101618A EP0441351A2 EP 0441351 A2 EP0441351 A2 EP 0441351A2 EP 91101618 A EP91101618 A EP 91101618A EP 91101618 A EP91101618 A EP 91101618A EP 0441351 A2 EP0441351 A2 EP 0441351A2
Authority
EP
European Patent Office
Prior art keywords
image forming
forming device
layer
image
roller
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.)
Granted
Application number
EP91101618A
Other languages
English (en)
French (fr)
Other versions
EP0441351A3 (en
EP0441351B1 (de
Inventor
Koichi Suwa
Masahiro Goto
Takahiro Inoue
Koichi Hiroshima
Shinichi Tsukida
Junichi Kato
Hideyuki Yano
Manabu Takano
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.)
Canon Inc
Original Assignee
Canon 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
Priority claimed from JP2929890A external-priority patent/JP2925217B2/ja
Priority claimed from JP16982390A external-priority patent/JPH0460570A/ja
Application filed by Canon Inc filed Critical Canon Inc
Publication of EP0441351A2 publication Critical patent/EP0441351A2/de
Publication of EP0441351A3 publication Critical patent/EP0441351A3/en
Application granted granted Critical
Publication of EP0441351B1 publication Critical patent/EP0441351B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • G03G15/206—Structural details or chemical composition of the pressure elements and layers thereof

Definitions

  • This invention relates to an image forming device such as electrophotographic device or electrostatic recording device, etc., typically copying machine, laser beam printer, etc., particularly to an image forming device equipped with a transfer means having a moving member which moves while pressing a recording means against an image carrying or bearing member as the means for transferring the image on the image carrying member onto the recording material, namely the so called contact type transfer means.
  • the image forming device of the prior art by use of the transfer means of the contact type is described by referring to a laser beam printer as shown in Fig. 1.
  • the unfixed toner image formed on the photosensitive drum by the primary charger 8, the laser beam scanner 1, the developing device 3 arranged respectively around the photosensitive drum 2 as the image carrying member is transferred by the transfer roller 4 pressure contacted with the photosensitive drum 2 onto the recording material 5.
  • the residual toner after transfer is recovered from the photosensitive drum 2 by the cleaning device 7.
  • the toner image transferred onto the recording material is fixed by the fixing device 14.
  • Fig. 2 is an enlarged sectional view of the fixing device 14.
  • the fixing device 14 has a pair of rollers arranged in pressure contact with each other, and fixing is carried out by heating the rollers by means of a heating means.
  • the fixing roller 15 has a constitution having a fluorine resin layer provided on the outer surface of a hollow aluminum core metal, and a halogen heater 11 is arranged therein.
  • the member 17 functions as both silicone oil coating and cleaning comprises the cleaning member 17A comprising a heat-resistant felt impregnated with a silicone oil and the holder 17B supporting this, which is pressed against the fixing roller 15.
  • the pressurizing roller 16 has the elastic layer 16A of, for example, the low temperature vulcanization type silicone rubber (LTV) around the core metal 16B.
  • LTV low temperature vulcanization type silicone rubber
  • the contact transfer device as represented by the transfer roller 4 which can perform transfer at lower voltage as compared with corona transfer device and therefore can transfer and convey a diversity of recording materials from thin paper to envelope, having further the advantage of little generation of ozone, and further excellent in conveying force of the recording material. As still another advantage, there is little poor or fault image generated during transfer. For this reason, it is effective for a compact electrophotographic printer, etc.
  • the life of the pressurizing roller becomes shorter, and as compared with durability of about 100,000 sheets when using a corona transfer device, durability life is shortened to about 30,000 sheets on account of pressurizing roller contamination.
  • the transfer roller 4 forms a roller pair with the photosensitive drum 2 which is an image carrying member and conveys the recording material.
  • a stress is applied on the recording material between the transfer roller 4 and the fixing device 14. Due to the influence by the stress, wrinkle of the recording material is liable to be generated when passing through the fixing device. The phenomenon is liable to be generated particularly in thin paper or envelope.
  • the transfer roller 4 an elastic material is employed for forming a nip between it and the photosensitive drum 2. At this time, if the nip is not formed under a low pressure, the so called void or hollow character phenomenon will be generated, which is the phenomenon in which the central portion of the character is not transferred. Therefore, a rubber of low hardness or a foamed sponge, etc. is used for the transfer roller 4. For this reason, the surface roughness of the transfer roller 4 is rough and also its coefficient of friction is high, thus also posing a problem that the toner can be cleaned with difficulty.
  • the present invention has been accomplished in view of the problems as described above, and has an object to provide an image forming device which can obtain images without image irregularity and with good fixability.
  • Another object of the present invention is to provide an image forming device which can prevent such phenomena as contamination of the recording material, winding of the recording material, etc.
  • Still another object of the present invention is to provide an image forming device which can perform stably conveying of the recording material irrespective of the kind of the recording material without generation of wrinkle, etc. on the recording material.
  • Still another object of the present invention is to provide an image forming device which can improve the durability life of the fixing device and can correspond to speed-up of image formation.
  • Fig. 3 shows an image forming device of an embodiment of the present invention. Description of those common with the members shown in Fig. 1 is omitted with attachment of the same symbols.
  • the rotatory member 4 for transfer as the moving member which moves while pressing a recording member against the image carrying member has an elastic material layer such as a rubber (e.g., EPDM, urethane, silicone, NBR, etc.) or a foamed sponge around its shaft core metal, and the resistance value of the elastic material layer is controlled by dispersing a filler such as carbon black, metallic powder, etc. or a metal oxide such as tin oxide, titanium oxide, zinc oxide, etc.
  • a rubber e.g., EPDM, urethane, silicone, NBR, etc.
  • a foamed sponge around its shaft core metal
  • a filler such as carbon black, metallic powder, etc. or a metal oxide such as tin oxide, titanium oxide, zinc oxide, etc.
  • the method of transmitting driving to the transfer roller by providing a driving gear on a photosensitive drum 2 as the image carrying member is used.
  • the transfer roller 4 has a hardness of 15 to 40 degrees (ASKERC), a resistance value of 106 to 109 ⁇ , with the circumferential speed being driven at a speed more rapid by 1 to 5% relative to the photosensitive drum 2, whereby a good transfer image without void or hollow character, defective transfer, etc. and also without poor or fault image can be obtained.
  • a transfer roller obtained by polishing the surface with an EPDM sponge with a hardness of 30 degrees (ASKERC) and a resistance value of 108 ⁇ to an outer diameter of 18 mm was used and it was driven at a circumferential speed more rapid by 3% than the photosensitive drum 2.
  • hardness is that after molded into the roller, the resistance value is a value of the resistance between the core metal and the electrode determined by application of a voltage of 1 KV when an electrode with a width of 10 mm was wound around the peripheral surface of the transfer roller 4, and the circumferential speed determined from the angular speed and the outer diameter of the transfer roller 4.
  • the distance between the nip formed between the transfer roller and the photosensitive drum and the roller pair for fixing as described below is shorter than the recording material length with the maximum size (with respect to the conveying direction of the recording material).
  • FIG. 4 An embodiment of the fixing device in the present invention is shown in Fig. 4.
  • the fixing device 6 in Fig. 3 has a pair of rotatory members as a pair of moving members for conveying a recording material sandwiched therebetween, and paired rotatory member is constituted of the fixing roller 9 and the pressurizing roller 10.
  • the fixing roller 9 has a hollow structure, having a fluorine resin layer 9A which was obtained by applying a primer around an aluminum core metal 9B with a reverse crown shape having an outer diameter at the central portion smaller than the edge portion, and then applying PFA dispersion coating, followed by sintering.
  • a halogen heater 11 for heating.
  • the fixing roller 9 is detected of its surface temperature by a temperature detecting device (not shown), and current passage to the heater 11 is controlled so that the detection temperature may be constant.
  • an HTV or LTV silicone rubber layer 10B is provided around the shaft-like core metal 10C, and further a tube 10A of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) coated as the upper layer thereon.
  • PFA tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer
  • the pressure roller 10 at this time is made to have a crown shape with the diameter at the central portion being made larger as compared with the edge portion.
  • the PFA tube has excellent non-tackiness as a matter of course as well as abrasion resistance, and therefore during usage over a long term, it can be a surface layer which can maintain non-tackiness.
  • the present inventors have conducted durability tests by use of a pressurizing roller with an outer diameter of 20 mm having a PFA tube coated on an LTV silicone rubber (JISA 15 degrees) with a thickness of 5 mm in the image recording device shown in Fig. 3, without providing neither a mold release agent coating mechanism nor a cleaning mechanism.
  • the transfer roller may have a rubber layer on the surface, and the pressurizing roller a resin layer on the surface.
  • the surface characteristic of a rubber layer has generally more stronger force of attaching toner, paper powder, etc. as compared with a resin layer, being also greater in frictional force, whereby the recording material conveying force is stronger, and also no slippage will occur.
  • the above-mentioned effect is further increased by making the rubber layer of the outermost layer a polished surface.
  • a rubbery material such as EPDM, NBR, urethane, silicone, etc., particularly a soft rubbery material with a hardness of 40 degrees or less (JISA) may be employed as the transfer roller, and in this case, the rubber surface should be desirably a polished surface, but also a surface just demolded can sufficiently function.
  • JISA soft rubbery material with a hardness of 40 degrees or less
  • the above-mentioned rubber may be also foamed to be molded into a sponge and the surface polished to give sufficient characteristics.
  • the surface of the pressurizing roller should be desirably formed of a resin layer having lubricity, mold releasability, and is further demanded to have heat resistance.
  • resin layer which can satisfy such demands there can be employed fluorine resins such as of polytetrafluoroethylene, tetrafluoroethylene-perfluoroalkyl ether copolymers, tetrafluoroethylene-hexafluoropropylene copolymers, etc., silicone resins and others.
  • the pressurizing roller may have a hardness in the range of from 30 to 70 degrees in terms of ASKERC, and the total pressure between the fixing roller and the pressurizing roller be 15 kg or lower, whereby a slippage can be caused to occur effectively with ease.
  • the fixing device can be made excellent in durability over a long term by merely applying a bias of the same polarity to that of the tone on the transfer roller without providing specially a cleaning means, etc. such as the transfer roller, whereby contamination of the pressurizing roller or generation of paper wrinkle can be also prevented. Further, the cleaning means, the mold release coating means, etc. can be also removed from the fixing device, whereby further simplification of the scanning device constitution can be simplified.
  • the specific feature of the present embodiment resides in that a layer comprising a mixture of a rubber and a fluorine resin is used for the surface of the pressurizing roller. Since other conditions such as the transfer roller, etc. are the same as in the foregoing embodiment, and their descriptions are omitted.
  • Fig. 5 is a sectional view showing the fixing device in the present embodiment.
  • the fixing roller 9 is made the same as in the embodiment described above, and the pressurizing roller 12 is a layer having an elastic layer 12C of a silicone rubber or a fluorine rubber provided around the core metal 12D, with its upper layers 12B and 12A being layers of calcined coating materials having a mixture of a fluorine resin and a fluorine rubber.
  • a fluorine resin layer 12A of a thin layer can be formed as the surface layer.
  • the mixture layer of the fluorine resin and the fluorine rubber is formed by, for example, coating an aqueous coating material of a fluorine rubber: Daiel Latex GL 213 (trade name, manufactured by Dakin Kogyo K.K.) be means of a spray gun, etc. to about 20 to 30 ⁇ m on the rubber layer 12C, and after drying, calcined at a temperature of 280°C or higher.
  • the surface layer of the fluorine resin such as 12A is formed by floating out of the fluorine resin onto the surface through Brownian movement.
  • the thickness of the surface layer 12A will vary depending on the calcination temperature and time, but when calcination is carried at 310°C for about 30 minutes, the layer thickness becomes about 5 ⁇ m, and yet the fluorine resin content becomes very high, whereby the property concerning non-tackiness becomes excellent.
  • the PFA tube roller as described in the foregoing embodiment is ASKERC 52° in terms of the roller hardness, while in the present embodiment, the roller hardness of the roller of the same diameter is very soft as ASKER C 37°.
  • the pressurizing force for obtaining the nip width sufficient for fixing may be smaller as compared with the PFA tube roller, whereby there is the advantage that the latitude of wrinkle of paper, envelope, etc. can be broadened.
  • a satisfactory nip can be formed under a low pressure, it becomes possible to make the image forming device higher in speed. Further, advantageous results are obtained with respect to abrasion of the pressurizing roller surface layer by friction with paper or fixing roller.
  • the pressurizing roller with a roller diameter of 20 mm heated at 310°C for 30 minutes was used for the fixing device of the image forming device by use of a transfer roller having no mold release coating mechanism and cleaning mechanism to carry out the durability test.
  • a transfer roller having no mold release coating mechanism and cleaning mechanism was used for the fixing device of the image forming device by use of a transfer roller having no mold release coating mechanism and cleaning mechanism to carry out the durability test.
  • a non-tacky pressurizing roller with low roller hardness can be obtained, whereby it becomes sufficiently possible to correspond to speed-up of the image forming device.
  • Fig. 6 is a schematic sectional view of the image forming device which is another embodiment of the present invention.
  • the specific feature of the present embodiment corresponds to higher speed-up, higher durability of the printer by improvement of the transfer roller 4 and the fixing device 6.
  • Other image forming portions of the present invention are the same as in the embodiment of Fig. 3 as described above, and their descriptions are omitted.
  • the transfer roller 4 was formed by providing an electroconductive foamed urethane sponge with a resistance value of 105 ⁇ with a thickness of 5 mm on a core metal made of iron or SUS with an outer diameter of 6 mm, and providing a urethane rubber having a volume resistivity value of 1010 ⁇ m with a thickness of 1 mm thereon to obtain a transfer roller with an outer diameter of 20 mm.
  • the transfer roller at this time had a roller hardness of 35 degrees in terms of ASKERC and a resistance value of 109 ⁇ .
  • soft rubber or foamed sponge has no abrasion resistance, and when used over a long term, the outer diameter becomes smaller and, when a transfer roller is driven, the circumferential speed becomes slower to lower the conveying force or generate flaws, whereby tone is embedded there to make cleaning impossible. For this reason, the durability life of the transfer roller was about 100,000 sheets, but the present embodiment has a durability performance of 300,000 sheets or more.
  • the specific feature of the fixing device resides in that the pressurizing roller life was extended by providing further a layer only of a fluorine resin on the surface layer of the pressurizing roller described in the embodiment in Fig. 5.
  • a silicone rubber or fluorine rubber layer 13D was provided and a mixture comprising a fluorine rubber and a fluorine resin was coated to about 20 to 30 ⁇ m (13C, 13B layers), followed by drying.
  • a FEP or PFA resin under emulsion state was coated to about 10 ⁇ m (layer 13A), followed by primary calcination.
  • the mixture layer of the fluorine resin and the fluorine rubber floats up to the side of the layer 13A through Brownian movement of the fluorine resin, whereby separation occurs into the layer 13B rich in the fluorine resin and the layer 13C rich in the fluorine rubber.
  • the layer 13B is well compatible with the fluorine resin 13A and therefore adhesion strength is increased. Then, calcination is carried out again at a higher temperature than in the primary calcination to melt the fluorine resin on the surface layer, thereby effecting complete adhesion and making the surface smoother.
  • the thickness of the fluorine resin layer becomes 10 ⁇ m or more, durability to contamination of the pressurizing roller will be improved as compared with the embodiment described in Fig. 5.
  • the roller hardness it is elevated by only about 3° in terms of ASKERC as compared with the pressurizing roller, a nip can be formed under a low pressure, whereby sufficient fixability can be obtained even if the printer is acclerated in speed and there is also sufficient effect for preventing generation of wrinkles of paper, envelopes.
  • the transfer roller and the fixing device can be used without exchange up to 300,000 sheets, whereby there can be provided an image forming device capable of giving fixability sufficiently corresponding to higher speed-up to about 120 mm/sec. in terms of paper delivery speed.
  • This embodiment is intended to lower the hardness of the pressurizing roller as described above in order to improve fixability and prevent the recording material from generation of wrinkles, etc.
  • the pressurizing roller 18 has an elastic material layer 18B around a shaft-shaped core metal 18C and further a fluorine resin layer 18A coated thereon.
  • a foamed HTV or LTV silicone rubber is used, and yet in said elastic material layer 18B exists a plurality of holes extending through the lengthy direction of the roller shaft.
  • a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) tube 18A is coated.
  • a specific feature of the pressurizing roller is that hardness can be controlled more easily at lower hardness as compared with when employing a silicone rubber solid, because a foamed material is used for the elastic material layer.
  • Fig. 8 outlines the mold when molding the elastic material of the present embodiment.
  • a pressurizing roller core metal 24 already applied with primer coating is mounted, and here a lid 22 is to be assembled.
  • the lid 22 has a core material 23 for providing thru-holes mounted. After mounting of the lid, a rubbery material containing a foaming agent is injected through a rubbery material inlet 26, foamed and vulcanized to be molded.
  • the effect of the pressurizing roller by use of the above-mentioned silicone rubber foam was ascertained by the experiment.
  • the image forming device shown in Fig. 3 was used, and the transfer roller capable of turning over the polarity of bias as described above was used.
  • the pressurizing roller as contrasted to the pressurizing roller as shown in Fig. 7, a pressurizing roller having a silicone rubber layer having no thru-hole was employed as control.
  • the pressurizing roller has the following specifications.
  • a foamed HTV silicone rubber was used with a thickness of 5 mm for the elastic layer of the pressurizing roller.
  • the foam is provided with 18 thru-holes with a diameter of 1 mm in the axial direction (dispersed uniformly within the circle).
  • the surface was coated with 50 ⁇ m of PFA tube.
  • the roller has an outer diameter of 20 mm and a roller hardness of 42° (ASKER C).
  • an LTV silicone rubber JIS A 20°
  • the surface layer was coated with 50 ⁇ m of PFA tube.
  • the roller had an outer diameter of 20 mm and a hardness of 55° (ASKER C).
  • the two kinds of pressurizing rollers as mentioned above were evaluated by the image forming device shown in Fig. 3.
  • the fixing roller at this time one having the structure of the embodiment as described above and an outer diameter of 25 mm was employed.
  • the pressurizing force of the fixing roller and the pressurizing roller were gradually increased, and the maximum pressurizing force when no wrinkle was generated was examined.
  • 0.28 kgf/cm was the maximum as the line pressure at the nip
  • 0.35 kgf/cm was the maximum.
  • the first pressurizing roller according to the present embodiment has a relatively lower hardness even the surface layer was coated with the PFA tube and no wrinkle is formed even when the pressurizing force is made higher. Thus, if the pressurizing force can be made higher, fixability will be improved.
  • the elastic material layer is provided with thru-holes, where by thermal expansion of the foam with heat receiving during fixing actuation can be absorbed to inhibit the change in roller diameter.
  • the thru-holes as mentioned above are required, but only holes, provided that they are continuous, can release the expanded air within the bubbles to obtain sufficient effect.
  • the phenomenon of diameter change due to thermal expansion does not only change the nip, thereby changing the fixing conditions, but when the surface is applied with PFA tube coating, when expansion, shrinkage are repeated, PFA tube is caused to generate wrinkles or generate peel off from the elastic material layer.
  • the pressurizing roller since the pressurizing roller has holes through the elastic material layer, and therefore the pressurizing roller can be made to have lower hardness, and no wrinkle will be generated even when the pressurizing force is made greater to give good fixability.
  • the pressure roller has a fluorine resin layer as the surface layer and therefore it exhibits more excellent lubricity than the surface layer of the transfer roller, whereby the stress of paper can be released to give rise to no wrinkle.
  • the fluorine resin surface layer of the pressurizing roller since the fluorine resin surface layer of the pressurizing roller exhibits more excellent mold releasability than the transfer roller surface layer, there is no contamination of the pressurizing roller surface, either.
  • This embodiment exhibits a specific embodiment in which the pressurizing roller is subjected to electroconductive treatment for prevention of off-set of the toner.
  • the material of the silicone rubber foam which is the elastic material layer of the pressurizing roller has generally a high volume resistivity of 1014 ⁇ cm, and yet is also coated on the surface layer with an insulating PFA tube.
  • the fixing roller 9 side is made to have the same structure as in the embodiment described above.
  • an electroconductive elastic material layer 19B is provided around the earthed core metal 19C, and further an electroconductive fluorine resin layer 19A is covered thereon. With these constitutions, the charges are permitted to escape to prevent the pressurizing roller from being charged up.
  • the elastic material layer 19B has a plurality of holes 19D extending through the foam of the same silicone rubber as described in the embodiment in Fig. 7 over the roller axis direction.
  • the silicone rubber for example, one which is made lower in resistance by dispersion of carbon to its volume resistivity of 1011 ⁇ cm or lower.
  • the fluorine resin layer 19A of the surface layer it is also subjected to electroconductive treatment, and for example, there is employed one which is made to have a volume resistivity of 1012 ⁇ cm or less with PFA tube made lower in resistance by dispersion of carbon.
  • roller hardness depends rather on the foaming conditions than the hardness of its own, and therefore it becomes to make lower the resistance without substantially accompanying increase in roller hardness.
  • the experiment conducted on the basis of the device of the present invention is described.
  • the electroconductive silicone rubber with a volume resistivity of about 105 ⁇ cm was employed for the foam, while for the electroconductive fluorine resin layer of the surface layer, one with a volume resistivity of about 1011 ⁇ cm and a thickness of 50 ⁇ m was employed.
  • the thickness of the elastic material layer was made 5.0 mm, and the pressurizing roller outer diameter 20 mm. In this case, the roller hardness was 45° (ASKER C).
  • the embodiment in Fig. 10 is different from that in Fig. 9 in that the surface layer of the pressurizing roller is made an insulating fluorine resin tube.
  • the fixing roller side is made the same as in the embodiment in Fig. 7.
  • the pressurizing roller 20 it has the constitution having an elastic material layer 20B which is an electroconductive foam and has a plurality of holes 13D extending therethrough with respect to its roller axis direction provided around the earthed core metal 20C and an insulating fluorine resin layer 20A on its surface layer.
  • the elastic material 20B is made the same as one described in the embodiment in Fig. 9, and the fluorine layer on the surface made the same as described in the embodiment in Fig. 7.
  • the charges obtained through friction between the fixing roller and the recording material cannot be escaped directly.
  • the electrostatic capacity between the core metal and the pressurizing roller surface is greater by about one order as compared with the insulating elastic material layer as described in the embodiment in Fig. 7. Therefore, even if the same amount of charges may be received, the potential elevation of the pressurizing roller is very small, and as a practical problem, in view of escape of charges into the air, it may be regarded that there is substantially no potential elevation of the pressurizing roller.
  • an electroconductive to be used for the foam may be one having a volume resistivity of about 105 ⁇ cm, and the fluorine resin layer of the surface layer was coated with PFA tube with a thickness of 50 ⁇ m.
  • the thickness of the elastic layer was made 5.0 mm, and the pressurizing roller outer diameter 20 mm.
  • the fixing roller 9 has a fluorine resin layer 9A on the surface of the core metal 9B, and a minus bias application is performed by a sliding electrode (not shown) by use of a DC power source 22 as its core metal 9B.
  • the pressurizing roller 21 has a foam which comprises an electroconductive silicone rubber and has a plurality of holes 21D extending therethrough in the roller axis direction as the elastic layer 21B, and has PFA tube 21A as the insulating fluorine resin layer on its surface layer provided around the core metal 21C, and a plus bias is applied through a sliding electrode (not shown) from the DC power source 23.
  • the elastic material layer of the pressurizing roller has low resistance, when a bias is applied, sufficient potential difference can be created between the pressurizing roller surface and the elastic material layer 21B, and therefore an electrical field for attracting the toner charged to minus toward the pressurizing roller side can be effectively obtained.
  • the embodiment in Fig. 12 is different from the embodiment in Fig. 11 in that an electrical field in a desired direction is formed between the fixing roller and the pressurizing roller by use of a diode without use of external bias.
  • the fixing roller and the pressurizing roller were made the same as those described in the embodiment in Fig. 11, and to the fixing roller metal core 9B was connected the diode 24 so that the fixing roller was on the minus side, while to the pressurizing roller metal core 21 was connected the diode 25 so that the pressurizing roller was on the plus side.
  • the function of the diode used here is influenced by mutual frictions between the fixing roller, the pressurizing roller, the recording material, the toner, etc. and the charges possessed by the respective members, and the charges will move between the respective core metals of the fixing roller and the pressurizing roller.
  • minus charges are selectively accumulated, and also plus charges selectively accumulated on the pressurizing roller side, whereby the fixing roller side is shifted to the minus potential and the pressurizing roller side to the plus potential.
  • the pressurizing roller 21 has on the core metal 21C an elastic material layer 21B with a thickness 5.0 mm having a plurality of holes 13D extending therethrough in the roller axis direction obtained by foaming of an HTV silicone rubber with a volume resistivity of about 105 ⁇ cm, and an insulating PFA tube 21A of 50 ⁇ m coated on the surface layer with the roller diameter being made 20 mm.
  • an HTV silicone rubber with a volume resistivity of about 105 ⁇ cm
  • an insulating PFA tube 21A of 50 ⁇ m coated on the surface layer with the roller diameter being made 20 mm.
  • bias or the diode may not be connected to the both rollers, but may also be done to only the pressurizing roller side or the fixing roller side.
  • the image forming device of the present invention relates to an image forming device having a moving member which moves while pressing a recording material against an image carrying member as the means of transferring the image on the image carrying member to the recording material. Further, the image forming device has a pair of moving members for fixing the image by conveying the recording material sandwiched therebetween, of which the moving member on the side not in contact with the unfixed image is a moving member having an elastic material layer and a resin surface layer. Further, the present invention has the surface of the moving member of the fixing means on the side not in contact with the unfixed image which is better mold releasability with that of the moving member of the transfer means.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Electrostatic Charge, Transfer And Separation In Electrography (AREA)
  • Fixing For Electrophotography (AREA)
  • Rolls And Other Rotary Bodies (AREA)
EP91101618A 1990-02-07 1991-02-06 Bilderzeugungsvorrichtung Expired - Lifetime EP0441351B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2929890A JP2925217B2 (ja) 1990-02-07 1990-02-07 画像形成装置
JP29298/90 1990-02-07
JP169823/90 1990-06-29
JP16982390A JPH0460570A (ja) 1990-06-29 1990-06-29 転写型画像形成装置

Publications (3)

Publication Number Publication Date
EP0441351A2 true EP0441351A2 (de) 1991-08-14
EP0441351A3 EP0441351A3 (en) 1992-06-03
EP0441351B1 EP0441351B1 (de) 1997-08-27

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP91101618A Expired - Lifetime EP0441351B1 (de) 1990-02-07 1991-02-06 Bilderzeugungsvorrichtung

Country Status (2)

Country Link
EP (1) EP0441351B1 (de)
DE (1) DE69127385T2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0469629A2 (de) * 1990-08-03 1992-02-05 Canon Kabushiki Kaisha Elastische Rolle und diese verwendendes Fixiergerät
EP0572020A2 (de) * 1992-05-29 1993-12-01 Sharp Kabushiki Kaisha Bilderzeugungsgerät

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5946664A (ja) * 1982-09-09 1984-03-16 Olympus Optical Co Ltd 複写機装置用転写ロ−ラ−
JPS61151676A (ja) * 1984-12-26 1986-07-10 Junkosha Co Ltd ロ−ラ定着装置
JPS61176954A (ja) * 1985-01-31 1986-08-08 Canon Inc 加熱ロ−ラ定着方法
JPS61212873A (ja) * 1985-03-18 1986-09-20 Fuji Xerox Co Ltd 電子複写機の定着装置

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JPS5946664A (ja) * 1982-09-09 1984-03-16 Olympus Optical Co Ltd 複写機装置用転写ロ−ラ−
JPS61151676A (ja) * 1984-12-26 1986-07-10 Junkosha Co Ltd ロ−ラ定着装置
JPS61176954A (ja) * 1985-01-31 1986-08-08 Canon Inc 加熱ロ−ラ定着方法
JPS61212873A (ja) * 1985-03-18 1986-09-20 Fuji Xerox Co Ltd 電子複写機の定着装置

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0469629A2 (de) * 1990-08-03 1992-02-05 Canon Kabushiki Kaisha Elastische Rolle und diese verwendendes Fixiergerät
EP0469629A3 (en) * 1990-08-03 1992-11-25 Canon Kabushiki Kaisha Elastic roller and fixing apparatus using same
US5420679A (en) * 1990-08-03 1995-05-30 Canon Kabushiki Kaisha Elastic roller and fixing apparatus using same
EP0572020A2 (de) * 1992-05-29 1993-12-01 Sharp Kabushiki Kaisha Bilderzeugungsgerät
EP0572020A3 (de) * 1992-05-29 1995-02-01 Sharp Kk Bilderzeugungsgerät.

Also Published As

Publication number Publication date
EP0441351A3 (en) 1992-06-03
DE69127385T2 (de) 1998-02-26
EP0441351B1 (de) 1997-08-27
DE69127385D1 (de) 1997-10-02

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