JP2006077132A - Elastomer composition for elastic member of electrophotographic device, electrically conductive member produced by using the same, and image forming device equipped with the electrically conductive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastomer composition for an elastic member of an electrophotographic device, capable of maintaining rubber elasticity, scarcely causing fluctuation in electric resistance, having stability to variation in the environment, including humidity and temperature, and to the elapse of time, easy in adjustment of the electric resistance, without deteriorating ozone resistance, and furnished with flame retardancy, to provide an electrically conductive member produced by using the composition, and to provide an image forming device equipped with the electrically conductive member. <P>SOLUTION: This elastomer composition for the elastic member of the electrophotographic device contains a rubber mixture comprising a chloroprene rubber, an epichlorohydrin rubber, and a flame retardant polymer, wherein a ratio (weight ratio) of a content of the chloroprene rubber to a content of the flame-retardant polymer is in a range of 95:5 to 5:95 and a ratio (weight ratio) of a total content of the chloroprene rubber and the epichlorohydrin rubber to the content of the flame retardant polymer is in a range of 100:10 to 100:50. The electrically conductive member is produced by using the composition. The image forming device is equipped with the electrically conductive member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an elastomer composition for an elastic member which is a material of a conductive elastic belt member, a roll member or a foamed member used in an electrophotographic apparatus, a conductive member produced using the same, and the conductive member The present invention relates to an image forming apparatus comprising:

In the electrophotographic apparatus, belt members such as a transfer belt, an intermediate transfer belt, a fixing belt, and a developing belt, and roll members such as a transfer roll and a fixing roll are used. The transfer belt or transfer roll is a member that transfers a toner image formed on a photosensitive member onto a printing material and conveys printing paper by electrostatic force, and the fixing belt or fixing roll is the printing material. A member for fixing the toner image transferred on the body onto the printing medium;
Therefore, the belt member and the roll member are provided with conductivity in order to prevent the toner from being hindered by static electricity. The common logarithmic value of the volume resistivity of these members is generally set in the range of 6 to 8 [log Ωcm] or 11 to 13 [log Ωcm] depending on the type of apparatus.

In addition, when the volume resistivity is lower than the above value, problems such as leakage, paper stains, and image quality disturbance may occur in the transfer belt. Further, if it exceeds the above value, transfer / charging efficiency is poor, and there are cases where adaptation at the time of repeated use becomes difficult.
On the other hand, additives that are normally used as flame retardant binders are classified as chlorinated polyethylene and ethylene-vinyl acetate copolymers, and sulfonated polyethylene as thermoplastic polymers, and permanent distortion during belt and roller molding. Can not withstand deformation. In addition, flame retardance is improved by using inorganic fillers such as Al hydroxide, ZnO, SnO ₂ , Zn · Sn (OH) ₆ and other oxides. Reinforcing property is not obtained.

Among the belt members and roll members, chloroprene rubber (CR), nitrile butyl rubber (NBR), and the like are used as materials used for the transfer belt and roll. Among them, CR has a common logarithm value of volume resistivity of 10 to 12 [log Ωcm]. Therefore, when adjusting this to 6 to 8 [log Ωcm], carbon powder, ionic conductive material, and ionic polymer Means for mixing such conductive additives is used.
Furthermore, sufficient flame retardancy and ozone resistance are not obtained with CR alone due to the influence of the addition of a filler such as silica, an organic vulcanizing component, a vulcanization accelerator, and an anti-aging material. On the other hand, NBR itself is mixed with hydrogenated H-NBR, etc., but ozone degradation due to blending with ethylene-propylene-diene copolymer rubber (EPDM), which is expensive and has excellent ozone resistance as a diene. Although resistance can be obtained, the flame retardancy tends to decrease with a decrease in the halogen content, and a compatible blending system cannot be selected (for example, see Patent Document 1).

  In addition, in the proposal of Patent Document 1, the variation of the electrical resistance value of the molded body due to the phase change of the sea-island structure due to the crystallization of the CR itself and the change with time increase, and conversely, the flame retardancy tends to decrease and the halogen content decreases. The problem of becoming. Although hydrogenated NBR with improved ozone resistance is used, there is a limitation in use due to cost increase, and there is a problem that the resistance adjustment ability is easily changed in the bias of the conductive material and filler dispersibility in the two-component system.

Among the conductive additives, carbon powder is very difficult to mix with the rubber described above, and it is difficult to uniformly mix a large amount of carbon powder with the rubber. Further, the molding variation appears in the in-plane potential fluctuation after the belt or roll molding, and tends to cause density unevenness or transfer unevenness on the image.
On the other hand, the ionic conductive material is easily kneaded uniformly with rubber, but has a hygroscopic property, and when added in a large amount, the conductivity is easily affected by environmental factors such as temperature and humidity. Furthermore, there is a problem that even if the ionic conductive material is uniformly mixed, it is likely to migrate gradually by applying a voltage by subsequent transfer.
JP-A-9-222809

  An object of the present invention is to solve the conventional problems. That is, the present invention maintains rubber elasticity, has little variation in electrical resistance, and can easily adjust the electrical resistance without deteriorating environmental fluctuations such as humidity and temperature, stability over time, and ozone resistance. An object is to provide an elastomer composition for an elastic member of an electrophotographic apparatus imparted with flame retardancy, a conductive member produced using the same, and an image forming apparatus comprising the conductive member. .

The object is achieved by the present invention described below.
That is, the present invention
<1> An elastomer composition for an elastic member of an electrophotographic apparatus containing a rubber mixture comprising chloroprene rubber, epichlorohydrin rubber, and a flame retardant polymer, the chloroprene rubber and the flame retardant polymer The content ratio (mass ratio) is in the range of 95: 5 to 5:95, and the total content of the chloroprene rubber and epichlorohydrin rubber and the content ratio of the flame retardant polymer content (Mass ratio) is in the range of 100: 10 to 100: 50. An elastomer composition for an elastic member of an electrophotographic apparatus.

<2> The <1>, wherein the flame retardant polymer is at least one selected from chlorinated polyethylene, sulfonated polyethylene, an ethylene vinyl acetate copolymer, and a copolymer thereof. It is an elastomer composition for elastic members of the electrophotographic apparatus described.
<3> The elastomer composition for an elastic member of an electrophotographic apparatus according to <1> or <2>, further comprising an inorganic flame retardant.

<4> The elastomer composition for an elastic member of an electrophotographic apparatus according to any one of <1> to <3>, further comprising a conductive material.
<5> The elastomer composition for an elastic member of an electrophotographic apparatus according to <4>, wherein the conductive material is carbon powder and / or an ionic conductive material.

<6> The elastomer composition for an elastic member of an electrophotographic apparatus according to <5>, wherein a content of the carbon powder with respect to 100 parts by mass of the rubber mixture is in a range of 1 to 80 parts by mass. is there.
<7> The elastomer for an elastic member of an electrophotographic apparatus according to <5> or <6>, wherein the carbon powder is a carbon powder having an average particle size of 70 nm or less and a DBP oil absorption of 180 ml / 100 g or less. It is a composition.

<8> The elastomer for an elastic member of an electrophotographic apparatus according to <5>, wherein the content of the ionic conductive material with respect to 100 parts by mass of the rubber mixture is in the range of 0.1 to 5 parts by mass. It is a composition.
<9> The elastomer composition for an elastic member of an electrophotographic apparatus according to <5> or <8>, wherein the ion conductive material is a quaternary ammonium salt.

<10> The elastomer composition for an elastic member of an electrophotographic apparatus according to <9>, wherein the quaternary ammonium salt contains at least one phenyl group in one molecule.
<11> The electrophotographic apparatus according to any one of <1> to <10>, wherein 1 to 200 parts by mass of an inorganic filler is further blended with 100 parts by mass of the elastomer composition. It is an elastomer composition for elastic members.

<12> The elastomer composition for an elastic member of an electrophotographic apparatus according to <11>, wherein the surface of the inorganic filler is treated with a silane coupling agent.
<13> The elastomer composition for an elastic member of an electrophotographic apparatus according to any one of <1> to <12>, wherein the common logarithm of the volume resistivity is 5 to 13 [log Ωcm] when 500 V is applied. is there.

<14> A belt-shaped conductive member produced using the elastomer composition for an elastic member of an electrophotographic apparatus according to any one of <1> to <13>.
<15> A roll-shaped conductive member produced using the elastomer composition for an elastic member of an electrophotographic apparatus according to any one of <1> to <13>.
<16> An image forming apparatus comprising the conductive member according to <14> or <15>.

  The present invention maintains rubber elasticity, has little variation in electrical resistance, and is easy to adjust electrical resistance and flame retardant without deteriorating environmental fluctuations such as humidity and temperature, stability over time, and ozone resistance. It is possible to provide an elastomer composition for an elastic member of an electrophotographic apparatus imparted with a property, a conductive member produced using the same, and an image forming apparatus comprising the conductive member.

  The elastomer composition for an elastic member of the electrophotographic apparatus of the present invention (hereinafter referred to as “the elastomer composition of the present invention”) includes a chloroprene rubber (CR), an epichlorohydrin rubber (ECO), a flame retardant polymer, A content ratio (CR: ECO, mass ratio) of the chloroprene rubber and the flame retardant polymer is in a range of 95: 5 to 5:95, and the chloroprene rubber and The content ratio of the total content of epichlorohydrin rubber and the content of the flame retardant polymer (total content of CR and ECO: content of flame retardant polymer, mass ratio) is 100: 10 to 100 : In the range of 50.

The CR has flame retardancy, is excellent in flexibility, and has a high volume resistivity (approximately 10 to 12 [log Ωcm] as a common logarithm when 500 V is applied), and the ECO is volume specific. Resistivity is low (usually logarithmic value at 500 V applied is approximately 5.5 to 6 [log Ωcm]).
In the elastomer composition of the present invention, by containing CR having a high volume resistivity and ECO having a low volume resistivity in a ratio of 95: 5 to 5:95, the CR and the ECO A volume specific resistivity (a common logarithmic value when 500 V is applied, 5.5 to 6 [log Ωcm] to 11 to 12 [log Ωcm]) can be arbitrarily obtained. In addition, since the CR and the ECO can be mixed uniformly without causing phase separation, variation in electric resistance can be reduced, and deterioration and a stable region of electric resistance can be controlled. Become.

  In the present invention, the volume resistivity is measured by using an ultra-high resistance / microammeter manufactured by Advantest Co., Ltd., using a Mitsubishi Oily HR probe, measurement environment: 23 ° C. and 55%, applied voltage of 500 V, and a value of 10 seconds. It was determined by measuring the value.

  Further, the elastomer composition of the present invention contains CR and ECO in a ratio of 95: 5 to 5:95 so that a conductive material such as a carbon powder or an ionic conductive material described later is not contained or is contained in a small content. Even so, it is possible to obtain a volume resistivity (5 to 13 [log Ωcm] as a common logarithmic value when 500 V is applied) preferable as a belt member or roll member of an electrophotographic apparatus described later. As a result, uneven dispersion due to containing a large amount of carbon powder can be prevented. Moreover, instability with respect to environmental factors and migration can be prevented by containing a large amount of ionic conductive material. Therefore, even when carbon powder is contained, an elastomer composition is obtained in which the carbon powder is uniformly dispersed, is not affected by environmental factors, and does not cause migration.

  In the elastomer composition of the present invention, the content ratio (mass ratio) of the CR and the ECO is preferably 90:10 to 10:90, and more preferably 80:20 to 20:80. .

The elastomer composition of the present invention contains a flame retardant polymer in such an amount that the content ratio (mass ratio) with respect to the total content of CR and ECO is 100: 10 to 100: 50.
Further, the content ratio (mass ratio) of the total content of CR and ECO and the flame retardant polymer is preferably 100: 15 to 100: 40, and preferably 100: 20 to 100: 30. Is more preferable.

By containing the flame retardant polymer in such an amount that the content ratio with respect to the total content of CR and ECO is 100: 10 to 100: 50, it does not contain an inorganic flame retardant described later, or an inorganic flame retardant Even if there is little content of, the desired flame retardance of the V-0-V-2 level in a flame retardance UL specification is obtained. As a result, it is possible to prevent adverse effects on electrical resistance due to a decrease in rubber physical properties and an increase in hygroscopicity due to hydroxyl groups by containing a large amount of inorganic flame retardant.
The flame retardant UL standard refers to UNDERWRITERS LABORATORIES INC. Of the United States. It is a safety standard for electrical equipment that has been established and approved by the company, and is a standard defined by a vertical combustion test using the UL combustion test method. There are V-0, V-1, and V-2 depending on the degree of flame retardancy, and the closer to V-0, the higher the flame retardant material. V-0 to V-1 level when there is no melt falling while burning within 10 seconds to 30 seconds or less, and V-2 when there is melt falling while burning.

  The CR used in the present invention is preferably slow in crystallinity, and may be modified CR such as mercaptan-modified, xanthogen-modified, sulfur-modified.

  Examples of the ECO used in the present invention include epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide binary copolymer, and epichlorohydrin-ethylene oxide-acryl glycidyl ether terpolymer.

  In the present invention, the flame retardant polymer means a polymer that is V-2 or higher in the UL94 standard, and uses one or more of chlorinated polyethylene and chlorinated butyl rubber, ethylene vinyl acetate rubber and sulfonated polyethylene. Among them, chlorinated polyethylene, sulfonated polyethylene, ethylene vinyl acetate copolymer, or at least one selected from these copolymers is preferable.

  In addition, by using sulfonated polyethylene with ionic conductivity and a copolymer with vinyl acetate as the flame retardant polymer, and controlling the amount of the ionic component (acid-base behavior) By taking in, it is possible to adjust the electric resistance without adding an ion conductive material to be described later.

The elastomer composition of the present invention may contain an inorganic flame retardant in order to control the flame retardancy more accurately. Examples of the inorganic flame retardant include hydrated metal compounds such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide, hydrates such as calcium aluminate, dihydrate gypsum, zinc borate, and barium metaborate. Are illustrated. Among these, what consists of magnesium hydroxide, aluminum hydroxide, and calcium hydroxide is preferable.
The content of the inorganic flame retardant is preferably 10 to 50 parts by mass and more preferably 15 to 40 parts by mass with respect to 100 parts by mass of the rubber mixture.

  In the elastomer composition of the present invention, a conductive material may be added in order to control the volume resistivity more accurately. In the present invention, it is preferable to use carbon powder and / or ionic conductive material as the conductive material.

Examples of the carbon powder include channel black, furnace black, acetylene black, and thermal black. The average particle size is preferably 70 nm or less, more preferably 60 nm or less, and even more preferably 50 nm or less. The DBP oil absorption is preferably 180 ml / 100 g or less, more preferably 150 ml / 100 g or less, and even more preferably 100 ml / 100 g or less. The DBP (dibutyl phthalate) oil absorption amount is defined in ASTM D2414-6TT and represents whether the DBP amount (ml) absorbed by 100 g of carbon black is large or small. Carbon blacks with a higher DBP oil absorption form longer chain bonds.
Moreover, when adding carbon powder to the elastomer composition of this invention, it is preferable that content of the said carbon powder with respect to 100 mass parts of said rubber mixtures exists in the range of 1-80 mass parts, 5-50 More preferably within the range of parts by mass, even more preferably within the range of 10 to 30 parts by mass. When the content of the carbon powder is in the range of 1 to 80 parts by mass, rubber reinforcement by carbon contributes and hardness adjustment is easily performed with a filler or the like.

  Examples of the ionic conductive material include metal salt-containing plasticizers such as lithium perchlorate ester plasticizers; triethylbenzylammonium chloride, trimethylbenzylammonium chloride, octadecylamine acetate, imidazoline derivative acetate, polyalkylene polyamine derivative Or a salt thereof; cationic surfactants such as octadecyltrimethylammonium chloride, trimethylaminoethylalkylamide halide, alkylpyridinium sulfate, alkyltrimethylammonium halide, and the like, among which quaternary ammonium salts are preferred. Including at least one phenyl group in one molecule, such as triethylbenzylammonium chloride, trimethylbenzylammonium chloride Quaternary ammonium salts that are more preferred. Such a quaternary ammonium salt is less likely to cause migration in the elastomer composition due to steric hindrance due to the phenyl group.

  Moreover, when the elastomer composition of this invention contains the said ion conductive material, it is preferable that content of the said ion conductive material with respect to 100 mass parts of said rubber mixtures exists in the range of 0.1-5 mass parts. More preferably, it is in the range of 0.5 to 3.0 parts by mass.

The elastomer composition of the present invention preferably has a mass ratio of carbon powder to ionic conductive material in the range of 1:50 to 1000: 1 when the carbon powder and the ionic conductive material are used in combination. More preferably, it is in the range of 10: 1 to 50: 1.
The adjustment of the electrical resistance value of the elastomer composition of the present invention is mainly performed by the amount of carbon powder added, and the ionic conductive material is preferably added for fine adjustment.

  The elastomer composition of the present invention preferably further contains an inorganic filler in order to impart flame retardancy, heat resistance, mechanical strength and the like to the composition. Examples of the inorganic filler include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and zinc hydroxide, calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium oxide, Titanium oxide, iron oxide, zinc oxide, alumina, silica, diatomaceous earth, dolomite, gypsum, talc, clay, asbestos, mica, glass fiber, carbon fiber, calcium silicate, bennite, white carbon, carbon black, iron powder, Inorganic fillers such as aluminum powder, stone powder, blast furnace slag, fly ash, cement and zirconia powder are preferred. In addition, when the said inorganic filler is what gives a flame retardance to a composition, it acts also as an inorganic flame retardant.

  The surface of the inorganic filler is preferably treated with a silane coupling agent. If the surface of the inorganic filler is treated with a silane coupling agent, the affinity of the inorganic filler improves with rubber, and it becomes easier to mix more uniformly.

  Furthermore, when the said inorganic filler is further mix | blended with the elastomer composition of this invention, it is with respect to 100 mass parts of said elastomer compositions. It is preferable that the compounding quantity of the said inorganic filler exists in the range of 1-200 mass parts, and it is more preferable that it exists in the range of 1-100 mass parts.

Moreover, when the said inorganic filler is a metal hydroxide, a flame retardance is provided further.
The elastomer composition of the present invention preferably has a flame retardancy of V-2 or higher.

  The elastomer composition of the present invention comprises phthalic acid plasticizers such as dioctyl phthalate (DOP), dibutyl phthalate (DBP), diisononyl phthalate (DINP); trimellitic acid plastics such as trimellitic acid tri-2-ethylhexyl (TOTM). Agents; dibasic acid plasticizers such as dioctyl adipate (DOA) and diisononyl dioctyl adipate (DINA); phosphate plasticizers such as tricresyl phosphate (TCP) and triphenyl phosphate (TPP); epoxy plastics Agents, plasticizers such as polyester plasticizers, softeners, other anti-aging agents, ultraviolet absorbers and the like may be added.

The volume resistivity of the elastomer composition of the present invention is preferably 5 to 13 [log Ωcm], more preferably 6 to 13 [log Ωcm] as a common body value when 500 V is applied, and the composition It is preferable that the difference in volume specific resistance is 3 or less when applied with 100V and when applied with 1000V.
When the thermoplastic resin is further added to the elastomer composition of the present invention, 1 to 100 parts by mass of the thermoplastic resin is added to 100 parts by mass of the rubber mixture.

When the elastomer composition of the present invention is used as a material for a belt-shaped or roll-shaped conductive member described later, it is preferable to further add a vulcanizing agent. Examples of the vulcanizing agent include sulfur, zinc oxide, magnesium oxide, hydrotalcide, two-component or three-component system of hydrotalcide and zinc oxide and / or magnesium oxide, and two components of zinc oxide and / or magnesium oxide and sulfur. Examples thereof include a component or a ternary system, and together with these, if desired, tetramethylthiuram monosulfide, di-O-triguanidine, thiourea and the like may be used in combination as a vulcanization accelerator.
The addition amount of the vulcanizing agent is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the elastomer composition when the vulcanizing agent is hydrotalcide, zinc oxide or magnesium oxide. It is more preferable that it is 3-7 mass parts. On the other hand, when the vulcanizing agent is sulfur, the amount is preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the elastomer composition.
Moreover, it is preferable that the addition amount of the said vulcanization accelerator is 5 mass parts or less with respect to 100 mass parts of said elastomer compositions.

  The elastomer composition of the present invention can be obtained by mixing desired amounts of CR, ECO, flame retardant polymer, and other additives. The mixing method is not particularly limited, but there are two or three rolls, a pressure kneader, and a rubber kneading method using a Banbury mixer for large scales, and various fillers and fillers are made of rubber. A method of pre-kneading with a kneader or a Banbury mixer and mixing chemicals such as additives and vulcanizing agents with a roll at the time of molding is preferred.

The conductive member of the present invention is a belt-shaped or roll-shaped conductive member manufactured using the elastomer composition for an elastic member of the electrophotographic apparatus of the present invention described above.
The method for producing the conductive member of the present invention is not particularly limited, and examples thereof include a method of forming into a belt shape or a roll shape by injection molding, mold molding or the like. In this case, the molding temperature is preferably set to 120 to 180 ° C., and vulcanization is preferably performed simultaneously with the molding.
Further, the conductive member of the present invention may use the elastomer composition molded into a belt shape or a roll shape as described above as a conductive member as it is, or further, an elastomer composition molded into a belt shape or a roll shape. One or two surface layers of polyester resin, urethane resin, fluorine resin, etc. are formed on the elastic layer for the purpose of improving releasability with respect to toner, preventing ozone deterioration, and reducing the friction coefficient. You may provide above.
Furthermore, when the conductive member of the present invention is in the form of a roll, when a metal core such as SUS is extruded and formed into a tube shape, or a rubber sheet is previously prepared in the mold and then formed into a roller shape by pressure hot press. You may form the elastomer composition of this invention on the base material which consists of the case where it shape | molds and surface-polishing and shape | molds in a roller shape.

In addition, the conductive member of the present invention has an Asuka C hardness after molding into a belt shape or a roll shape (after vulcanization) (load: 1 kg, measurement temperature: 23 ° C., using Asker C hardness meter manufactured by Kokubunshi Keiki Co., Ltd.) ) Within a range of 60 degrees to 80 degrees, and micro hardness (measured under conditions of 23 ° C. using a micro rubber hardness meter MD-1 type manufactured by Kobunshi Keiki Co., Ltd.) is 50 to 50 degrees. It is preferably within the range of 90 degrees.
When the conductive member of the present invention has a belt shape, the thickness is preferably 0.2 to 2.0 mm, the circumferential length 60 to 600 mm, and the width 200 to 600 mm. When the conductive member of the present invention has a roll shape, an elastic layer made of the elastomer composition of the present invention is formed around the substrate, and the outer diameter is 6 to 20 mm, and the elastic layer thickness is 1 to 5 mm. preferable.

The image forming apparatus of the present invention is an image forming apparatus comprising the above-described conductive member. The image forming apparatus of the present invention is preferably used as a transfer belt when the conductive member of the present invention has a belt shape, and as a transfer roll when the conductive member of the present invention has a roll shape.
Hereinafter, an embodiment of an image forming apparatus including a belt-shaped conductive member of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram for explaining one embodiment of an image forming apparatus of the present invention.
In FIG. 1, reference numeral 10 denotes a photosensitive drum (image carrier) which rotates in the direction of arrow A. Then, around the photosensitive drum 10, a charger 11 for uniformly charging the drum surface (photosensitive layer), an electrostatic image is exposed by exposing the charged photosensitive drum 10 to an optical image corresponding to predetermined image information. An image exposure device 12 for forming a latent image, a developing device 13 for supplying a developer to the surface of the photosensitive drum 10 to develop the electrostatic latent image into a toner image, and a toner image T as a recording paper (final recording medium) P There are disposed a belt type transfer device 18 for transferring toner, a cleaning device 14 for removing the toner and the like remaining on the photosensitive drum 10 after transfer.

  Reference numeral 15 denotes a paper feed tray for storing recording paper P in a stacked manner, 15a denotes a feed roll for feeding the recording paper P from the paper feed tray 15 one by one, and 16 denotes the recording paper P sent from the paper feed tray 15. A registration roll 17 is sent out between the photosensitive drum 10 and the transfer device 18 at a predetermined timing, and 17 is a roll type fixing device for fixing the transferred toner image onto the recording paper P.

  In the present embodiment, the transfer device 18 includes a belt-shaped transfer belt (endless belt, final transfer medium transport belt) 20 made of the conductive member of the present invention, and the photosensitive drum 10 in a state where the transfer belt 20 is stretched. Support rolls 21 and 22 that are supported so as to rotate in the direction of arrow B in synchronization; a bias power source (transfer means) 23 that supplies a transfer bias having a polarity opposite to the toner charging polarity of the transfer toner image to the transfer belt 20; A main part is composed of a power supply roll (transfer means) 24 that applies a transfer bias output from the bias power source 23 to the transfer belt 20 and a cleaning blade 25 that removes toner and the like adhering to the transfer belt 20. .

  The transfer belt 20 is disposed so as to form a transfer nip portion (transfer portion) N by contacting the photosensitive drum 10 while being stretched by two support rolls 21 and 22. At least the support roll 21 on the upstream side of the transfer nip N is disposed in a grounded state, and one of the two support rolls is a drive roll for the transfer belt 20. (The support roll 21 in this example) is a drive roll for the transfer belt 20.

  Further, the power supply roll 24 is disposed between the two support rolls 20 and 21 that support the surface in contact with the photosensitive drum 1 so as to contact the back side of the transfer belt 20. The bias power source 23 outputs a transfer bias having a bias waveform composed of rectangular pulses.

  Further, a motor 30 that drives the photosensitive drum 1 and a motor (belt drive means) 31 that is a drive roll that drives a drive roll that rotates the transfer belt 20 and a support roll of the transfer belt 20 are provided. ing. The motor 30 and the motor 31 have a structure capable of outputting the rotation state of an encoder or the like inside, and the output is sent to the drive controller 70 as needed. The drive controller (rotation drive control means) 70 is equipped with a comparison circuit that monitors the rotation state sent from the motor 30 and the motor 31 and compares the rotation speeds of the two motors. The rotation of the motor 30 and the motor 31 is controlled.

  On the other hand, the bias power source 23 that applies a bias to the power supply roll 24 is controlled by a controller (electric field determination means) 19 that is a control unit of the bias power source. An appropriate bias value is applied to the power supply roller 24 at an appropriate timing under the control of the controller 19. The voltage value applied to the power supply roll 24 is monitored by the controller 19 and the information (transfer electric field) is sent to the drive controller 70 described above.

Next, an image forming process in an embodiment of the image forming apparatus of the present invention will be described.
First, the photosensitive layer of the rotating photosensitive drum 10 is uniformly charged by a charger 11, and an optical image composed of an optical image or image-modulated laser beam in which reflected light from an original is converged on the charged surface by an image exposure device 12. The image is irradiated to form an electrostatic latent image. Subsequently, toner is supplied from the developing device 13 and adheres only to the electrostatic latent image on the photosensitive drum 10 to form a toner image T. In this example, the photosensitive drum 10 is uniformly charged to a negative polarity to form an electrostatic latent image for reversal development, and then developed with a negatively charged toner. Therefore, the negatively charged toner image T Is to be formed.

  Subsequently, in accordance with the formation timing of the toner image T, the recording paper P of a predetermined size and type is sent out from the paper feed tray 15 one by one by the feed roll 15a, and the timing is adjusted by the registration roll 16. It is sent out toward the transfer nip N. A predetermined voltage (V 0) or a predetermined current (I 0) is applied from the bias power source 23 based on an instruction from the controller 19 immediately before the leading edge of the recording paper P passes through the transfer nip N.

  As a result, the recording paper P is fed to the transfer nip N facing the photosensitive drum 10 and then electrostatically attracted to the surface of the transfer belt 20, and the photosensitive drum 10 is exposed to the photosensitive drum 10 at an appropriate speed. The toner image T is electrostatically transferred from 10. The recording paper P onto which the toner image T has been transferred is separated from the belt at the portion of the transfer belt 20 supported by the support roll 22 and peeled off, and then sent to the fixing device 17 where the toner image T is fixed. Is applied and finally discharged outside the device. Thus, an image is formed.

  Since the image forming apparatus of the present invention uses the conductive member of the present invention as the transfer belt 20, it is caused by belt resistance change or permanent elongation due to ozone degradation, rubber degradation, etc. due to discharge between paper and photosensitive drum during use. The belt speed fluctuation is suppressed, stable paper adsorbability and paper transportability are obtained even for a long time, and the transfer characteristics are also stable.

<Examples 1-7, Comparative Examples 1-4>
Samples having the composition shown in Table 1 below were kneaded (55 L scale, pressure kneader used, 100 ° C., 20 minutes kneaded) and press-pressed (vacuum, 50 t press, 160 ° C., 15 minutes molded). Thus, a test piece having a thickness of 2 mm, a length of 150 mm, and a width of 200 mm was formed to obtain samples of Examples 1 to 7 and Comparative Examples 1 to 4.
In addition, the number in a table | surface represents a mass part. Further, triethylbenzyl chloride, which is an ionic conductive material, was used by dissolving 1 part by mass in 5 ml of water.

The following evaluation was performed about the sample of obtained Examples 1-7 and Comparative Examples 1-4. The results are shown in Table 2.
(Common logarithm of volume resistivity)
Using an ultra-high resistance / microammeter manufactured by Advantest Corp., measuring the value after 10 seconds with a measurement environment of 23 ° C. and 55% RH, an applied voltage of 500 V, using an HR probe (JIS-K6911) manufactured by Mitsubishi Oil Chemical Co., Ltd. Specific resistivity was obtained. Based on this value, the common logarithm of the volume resistivity was calculated.

(Variation of common logarithm of volume resistivity)
The volume resistivity was measured at three points in the vertical and horizontal directions, and the variation in the common logarithm of the volume resistivity was calculated from the difference between the maximum and minimum common logarithm values of the measured volume resistivity.

(Environmental change)
The difference in volume resistivity in a low temperature and low humidity environment (LL: 15 ° C., 30% RH) and a high temperature, high humidity environment (HH: 28 ° C., 85% RH) was defined as the environmental fluctuation range.

(Flame retardance)
Using a sheet piece according to the vertical flame retardant test method defined in UL94, evaluation is performed based on the flaming and nonflammable combustion times after flame contact and the presence or absence of combustion droplets according to UL94. did. When there is no melt (burning drops) that burns while burning for 10 seconds or less to 30 seconds or less, there is a V-0 to V-1 level, and there is a melt (burning drops) that falls while burning The case is V-2.

From Table 2, the samples of Examples 1 to 7 containing CR, ECO, and a flame retardant polymer have small variations in common logarithm of volume resistivity, further reduced environmental fluctuation, and also have flame retardancy. I understand that.
On the other hand, it can be seen that the samples of Comparative Examples 3 and 4 that do not contain ECO have a large variation in the common logarithm of the volume resistivity, and the environmental fluctuation is also worsening. Moreover, it turns out that the comparative example 2 which does not contain a flame retardant polymer has deteriorated the flame retardance. Further, it can be seen that Comparative Example 1 containing an inorganic flame retardant instead of the flame retardant polymer has good flame retardancy, but the environmental fluctuation is worse.

1 is a schematic configuration diagram for explaining one embodiment of an image forming apparatus of the present invention.

Explanation of symbols

10 Photosensitive drum,
11 Charger,
12 image exposure apparatus,
13 Development device,
14 Cleaning device,
15 Paper tray,
15a feed roll,
16 resist rolls,
17 roll type fixing device,
18 Transfer device,
19 controller,
20 transfer belt,
21, 22 support rolls,
23 Bias power supply,
24 Power feed roll,
25 Cleaning blade,
30, 31 motor,
70 drive controller,
T toner image,
P recording paper,
N Transfer nip

Claims (4)

An elastomer composition for an elastic member of an electrophotographic apparatus, comprising a rubber mixture comprising chloroprene rubber, epichlorohydrin rubber, and a flame retardant polymer,
The content ratio (mass ratio) of the chloroprene rubber and the flame retardant polymer is in the range of 95: 5 to 5:95,
And the content ratio (mass ratio) of the total content of the chloroprene rubber and the epichlorohydrin rubber and the content of the flame retardant polymer is in the range of 100: 10 to 100: 50, An elastomer composition for an elastic member of an electrophotographic apparatus.   A belt-shaped conductive member produced using the elastomer composition for an elastic member of an electrophotographic apparatus according to claim 1.   The roll-shaped electroconductive member manufactured using the elastomer composition for elastic members of the electrophotographic apparatus of Claim 1.   An image forming apparatus comprising the conductive member according to claim 2.

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