JP2008096888A - Cleaning member, electrophotographic apparatus, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning member designed to have improved slidability and wear resistance, thereby ensuring cleaning performance for a long time, and prevent sticking of dust due to static electricity, and to provide an electrophotographic apparatus, fixing device, and image forming apparatus that use the cleaning member. <P>SOLUTION: For example, a cleaning member (cleaning sheet 60) comprises a polymide resin member containing carbon black. This cleaning member is disposed in an electrophotographic member for the image forming apparatus, such as a heat roll for the fixing device 28, transfer rolls 5Y to 5K, or a secondary transfer roll 26. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning member, an electrophotographic apparatus, a fixing apparatus, and an image forming apparatus.

  Various rolls are used in printers, facsimiles, electrophotographic copying machines, and the like. Among them, the fixing roll is a roll for heating and fixing the toner image transferred onto the paper, but toner or paper dust may remain on the surface of the fixing member (for example, the fixing roll). It is easy to produce dirt.

  On the other hand, charging members (for example, charging rolls) are charged by contacting the photosensitive drum. However, residual toner, paper dust, or discharge products on the photosensitive drum adhere to the charging roll, resulting in contamination. Cheap.

  In Patent Documents 1 and 2, in order to clean the fixing member, the polyimide resin sheet is brought into contact with the fixing member. In Patent Document 3, the polyimide resin film is used as the charging member in order to clean the charging member. The contact is described.

  In any case, the reason for using the polyimide resin film is that it has a suitable hardness and good sliding property, and is a material that is difficult to wear. May damage the member, and conversely, the polyimide resin sheet may be damaged by contaminants, and a better material has been demanded. In addition, since the polyimide resin film has high electrical insulation, dust adheres due to static electricity and may enter the contact surface with the member to cause cleaning failure.

JP 2001-228738 A JP 2005-300802 A JP 2004-54141 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a cleaning member that is improved in slidability and wear resistance, maintains cleanability for a long period of time, and prevents dust from adhering to static electricity. Another object of the present invention is to provide an electrophotographic apparatus, a fixing apparatus, and an image forming apparatus using the cleaning member.

The above problem is solved by the following means. That is,
The invention according to claim 1
A cleaning member comprising a polyimide resin member containing carbon black.

The invention according to claim 2
A cleaning member comprising a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm.

The invention according to claim 3
An image forming apparatus comprising the cleaning member according to claim 1.

The invention according to claim 4
An electrophotographic member;
A cleaning member disposed in contact with the electrophotographic member and cleaning the surface of the electrophotographic member, the cleaning member having a polyimide resin member containing carbon black;
An apparatus for electrophotography, comprising:

The invention according to claim 5
An electrophotographic member;
A cleaning member disposed in contact with the electrophotographic member and cleaning the surface of the electrophotographic member, the cleaning member having a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm; ,
An apparatus for electrophotography, comprising:

The invention according to claim 6
An image forming apparatus comprising the electrophotographic apparatus according to claim 4.

The invention according to claim 7 provides:
A fixing member;
A cleaning member disposed in contact with the fixing member and cleaning the surface of the fixing member, the cleaning member having a polyimide resin member containing carbon black;
And a fixing device.

The invention according to claim 8 provides:
A fixing member;
A cleaning member disposed in contact with the fixing member and cleaning the surface of the fixing member, the cleaning member having a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm;
And a fixing device.

The invention according to claim 9 is:
An image forming apparatus comprising the fixing device according to claim 7.

  According to the present invention, it is possible to provide a cleaning member that is improved in slidability and wear resistance, maintains cleanability for a long period of time, and further prevents dust from being attached due to static electricity. Further, according to the present invention, it is possible to provide an electrophotographic apparatus, a fixing apparatus, and an image forming apparatus using the cleaning member.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is provided to the member which has the substantially same function through all the drawings, and the overlapping description may be abbreviate | omitted.

  FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating the charging roll according to the embodiment. FIG. 3 is a perspective view illustrating the charging roll according to the embodiment. FIG. 4 is a schematic configuration diagram illustrating the fixing device according to the embodiment. FIG. 5 is a perspective view illustrating a main part of the fixing device according to the embodiment.

  As shown in FIG. 1, the image forming apparatus 100 according to the embodiment outputs an image of each color of yellow (Y), magenta (M), cyan (C), and black (K) based on the color-separated image data. Electrophotographic first to fourth process cartridges (image forming stations) 10Y, 10M, 10C, and 10K (image forming means). These process cartridges 10Y, 10M, 10C, and 10K are arranged side by side along the outer peripheral surface of the intermediate transfer belt 20 with a predetermined distance therebetween. The process cartridges 10Y, 10M, 10C, and 10K are detachable from the image forming apparatus main body.

  Above each process cartridge 10Y, 10M, 10C, 10K (in the drawing), an intermediate transfer belt 20 as an intermediate transfer member is extended so that its outer peripheral surface faces each process cartridge. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20 while being provided with tension, and the first process cartridge 10Y to the fourth process. Endless running is performed in the direction toward the cartridge 10K.

  The support roll 24 is pressed in a direction away from the drive roll 22 by an elastic member such as a spring (not shown), and a predetermined tension is applied to the intermediate transfer belt 20 wound between them. An intermediate transfer member cleaning device 20 a is provided on the outer peripheral surface of the intermediate transfer belt 20 so as to face the drive roll 22.

  Since the first to fourth process cartridges 10Y, 10M, 10C, and 10K have the same configuration (different developer types), here, the yellow image disposed on the upstream side in the intermediate transfer belt traveling direction is displayed. The first process cartridge 10Y to be formed will be described as a representative. The same reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as the first process cartridge 10Y instead of yellow (Y), so that the second to second Description of the four process cartridges 10M, 10C, and 10K is omitted.

  The first process cartridge 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (charging means) 2Y for charging the surface of the photoreceptor 1Y to a predetermined potential and a toner (developer) charged to the electrostatic latent image are supplied to develop the electrostatic latent image. A developing device 4Y that performs this operation, and a photoconductor cleaning device 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer are sequentially disposed. These are integrally formed in the housing 11Y (housing). Similarly, in the first process cartridges 10M to 10Y, the respective members are integrally formed in the housings 11M to 11Y (housing).

  Here, the process cartridge is not limited to the above-described configuration, and may have any of the above-described members (at least a charging member in the present embodiment) as long as it is detachable from the image forming apparatus.

  Then, together with the first process cartridge 10Y, a primary transfer roll 5Y (primary transfer means) for transferring the developed toner image (developer image) onto the intermediate transfer belt 20, and an image obtained by color-separating the charged surface An exposure device 3 that forms an electrostatic latent image by exposure with a laser beam 3Y based on the signal is arranged to constitute an image forming unit.

  The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is provided at a position facing the photoconductor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roll under the control of a control unit (control means) (not shown).

  Next, the charging roll 2Y will be described. As shown in FIGS. 2 and 3, the charging roll (charging means) 2Y includes, for example, a structure in which an elastic layer 2B and a resin layer 2C are sequentially formed on the surface of a metal base 2A. A cleaning sheet 60 (cleaning member) for cleaning the roll is disposed in contact with the surface of the charging roll 2Y. The cleaning sheet 60 includes carbon black and includes a polyimide resin having a predetermined volume resistivity. This polyimide resin will be described later.

  The cleaning sheet 60 has a length equivalent to the axial direction length of the charging roll 2Y or the use area (discharge area). The cleaning sheet 60 is supported by a support member (not shown), and its longitudinal direction is along the axial direction of the charging roll 2Y and its free end is directed to the rotational direction side of the charging roll 2Y. Is in contact with the outer peripheral surface of the charging roll 2Y. The thickness of the cleaning sheet 60 is, for example, about 50 μm to 150 μm. The cleaning member may be formed not only in a sheet shape but also in a brush shape, or may have a notch or an opening hole. Further, the cleaning sheet 60 may be swung in the axial direction of the charging roll 2Y.

  The other charging rolls 2Y2M to 2K are similarly provided with cleaning sheets 60, respectively.

  The base material 2A of the charging roll 2Y functions as an electrode and a support member for the charging roll. For example, a metal or an alloy such as aluminum, copper alloy, or stainless steel; iron that has been plated with chromium, nickel, or the like; A conductive material such as a conductive resin;

  The elastic layer 2B of the charging roll 2Y is formed, for example, by dispersing a conductive agent in a rubber material. Rubber materials include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, polyurethane, silicone rubber, fluorine rubber, styrene-butadiene rubber, butadiene rubber, nitrile rubber, ethylene propylene rubber, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide- Examples include allyl glycidyl ether copolymer rubber, ethylene-propylene-diene terpolymer rubber (EPDM), acrylonitrile-butadiene copolymer rubber (NBR), natural rubber, and blend rubbers thereof. Among these, polyurethane, silicone rubber, EPDM, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer rubber, NBR and blended rubbers thereof are preferably used. These rubber materials may be foamed or non-foamed.

  As the conductive agent, an electronic conductive agent or an ionic conductive agent is used. Examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, stainless steel; tin oxide, indium oxide, titanium oxide Examples thereof include fine powders such as various conductive metal oxides such as tin oxide-antimony oxide solid solution and tin oxide-indium oxide solid solution; Examples of ionic conductive agents include perchlorates and chlorates such as tetraethylammonium and lauryltrimethylammonium; alkali metals such as lithium and magnesium; perchlorates and chlorates of alkaline earth metals Can be mentioned.

These conductive agents may be used alone or in combination of two or more.
Moreover, the addition amount is not particularly limited, but in the case of the electronic conductive agent, it is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the rubber material, and in the range of 15 to 25 parts by mass. More preferably. On the other hand, in the case of the ionic conductive agent, it is preferably in the range of 0.1 to 5.0 parts by mass, and in the range of 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the rubber material. Is more preferable.

  The polymer material constituting the resin layer 2C of the charging roll 2Y is not particularly limited, but polyamide, polyurethane, polyvinylidene fluoride, tetrafluoroethylene copolymer, polyester, polyimide, silicone resin, acrylic resin, polyvinyl butyral, Examples include ethylene tetrafluoroethylene copolymer, melamine resin, fluororubber, epoxy resin, polycarbonate, polyvinyl alcohol, cellulose, polyvinylidene chloride, polyvinyl chloride, polyethylene, and ethylene vinyl acetate copolymer.

  The above polymer materials may be used alone or in combination of two or more. Further, the number average molecular weight of the polymer material is preferably in the range of 1,000 to 100,000, and more preferably in the range of 10,000 to 50,000.

For the resin layer 2C, the conductive agent used for the elastic layer 2B can be used as a conductive material.
Moreover, the addition amount is not particularly limited, but is preferably in the range of 1 to 50 parts by mass, more preferably in the range of 5 to 40 parts by mass with respect to 100 parts by mass of the polymer material.

  Next, the fixing device 28 will be described. As shown in FIGS. 4 and 5, the fixing device 28 includes a heating roll 30 and a pressure belt 40, and the heating roll 30 and the pressure belt 40 are provided to face each other. The pressure belt 40 is pressed against the heating roll 30 by a pressure pad 50 (pressure member) disposed inside the circumference, and is pressed along the belt travel guide 52 while being pressed to form a contact portion. The pressure belt 40 is driven by receiving the driving force from the roll 30. In the figure, T indicates a toner image.

  The heating roll 30 is configured, for example, by sequentially forming an elastic layer 30b and a release layer 30c on a metal hollow core metal core 30a having a heating source 31 such as a halogen lamp inside.

  These metal cores 30a are made of, for example, a cylindrical body made of metal such as aluminum or stainless steel. The elastic layer 30b is made of, for example, HTV silicone rubber, fluorine rubber or the like (JIS-A rubber hardness is about 45 degrees, and the rubber hardness is a spring type A type hardness meter manufactured by Teclock, in accordance with JIS K6301. (Measured by adding a load of 1,000 gf) with a thickness of about 2 to 5 mm. The release layer 30c is made of, for example, fluorine rubber, silicone rubber, fluorine resin, or the like with a thickness of 20 to 50 μm. Of course, it is not restricted to these, It can comprise by a conventionally well-known material.

  The heating roll 30 is rotationally driven at a predetermined speed, for example, a peripheral speed of 260 mm / sec, by a driving source (not shown). The outer diameter of the heating roll 30 is generally about 25 to 80 mm, for example.

  The surface temperature of the heating roll 30 is detected by a temperature sensor (not shown) that contacts the surface, and is controlled by a control circuit (not shown) so that the surface temperature becomes 175 ° C., for example.

  On the outer peripheral surface of the heating roll 30, a peeling member 32 for peeling the paper after fixing is provided.

  A cleaning sheet 60 (cleaning member) for cleaning the roll is in contact with the surface of the heating roll 30. The cleaning sheet 60 includes carbon black and includes a polyimide resin having a predetermined volume resistivity. This polyimide resin will be described later.

  The cleaning sheet 60 has a length that is equal to the axial length of the heating roll 30 or a length that is equivalent to a use area (area that contacts the recording medium P). The cleaning sheet 60 is supported by the illustrated support member, and the longitudinal direction of the cleaning sheet 60 is along the axial direction of the heating roll 30 and the free end of the cleaning sheet 60 faces the rotation direction of the heating roll 30. The surface is disposed in contact with the outer peripheral surface of the heating roll 30. The thickness of the cleaning sheet 60 is, for example, about 50 μm to 150 μm.

  The pressure belt 40 is configured by forming a release layer on a resin base material including a heat resistant resin such as a polyimide resin, for example. A resin base material and a release layer can be comprised with a conventionally well-known material.

  The pressure pad 50 (pressure member) has two pressure portions 51 a and 51 b having different hardnesses along the traveling direction of the recording medium P. The pressure portion 51a on the recording medium P entry side in the pressure pad 50 is made of a rubber-like elastic member, and the pressure portion 51b on the recording medium P discharge side is made of a hard pressure applying member such as metal, so that the pressure in the contact area is increased. Is set higher on the recording medium P discharge side than on the recording medium P entry side. The pressurizing units 51a and 51b are supported by a holder 51c, and the heating roll 30 is provided from the inner peripheral surface of the pressurizing belt 40 via a low friction layer 51d such as a glass fiber sheet or a fluororesin sheet including Teflon (registered trademark). Pressing.

  In addition, about another member, it can be set as a well-known structure. The primary transfer rolls 5Y to 5K and the secondary transfer roll (secondary transfer means) 26 are also provided with a cleaning sheet 60 similar to the heating roll 30 of the charging roll 2Y.

  Hereinafter, the image forming operation will be described as a representative of the operation of forming the yellow image in the first process cartridge 10Y.

  First, prior to the image forming operation, the surface of the photoreceptor 1Y is charged to a potential of about −600 V to −800 V, for example, by the charging roll 2Y.

  The photoreceptor 1Y is formed, for example, by laminating a photosensitive layer on a conductive substrate. This photosensitive layer is, for example, usually high in resistance, but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

  The electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y is reduced. On the other hand, it is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.

  The electrostatic latent image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic latent image on the photoreceptor 1Y is converted into a visible image (toner image) by the developing device 4Y.

  In the developing device 4Y, for example, the volume average particle size formed of at least a yellow colorant, a wax, a binder resin, and an aliphatic hydrocarbon-copolymer petroleum resin having 9 or more carbon atoms is 7 μm. Contains yellow toner. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, yellow toner is electrostatically attached only to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

  When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roll 5Y, and electrostatic force directed from the photoreceptor 1Y to the primary transfer roll 5Y is applied to the toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the polarity (−) of the toner. For example, in the first process cartridge 10Y, a constant current is controlled to about +10 μA by a control unit (not shown). Yes.

  Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second process cartridge 10M is similarly controlled.

  Thus, the intermediate transfer belt 20 to which the yellow toner image is transferred by the first process cartridge 10Y is sequentially conveyed through the second to fourth process cartridges 10M, 10C, and 10K, and the toner images of the respective colors are similarly overlapped and multiplexed. Transcribed.

  The intermediate transfer belt 20 on which, for example, toner images of all colors have been multiplex-transferred through the first to fourth process cartridges, the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt 20 and the image holding surface of the intermediate transfer belt 20. The secondary transfer roll (secondary transfer means) 26 arranged on the side reaches a secondary transfer portion. On the other hand, the recording medium P is fed between the secondary transfer roll 26 and the intermediate transfer belt 20 via the supply mechanism at a predetermined timing, and a predetermined secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording medium P is applied to the toner image, so The toner image is transferred onto the recording medium P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is controlled by a constant voltage, for example. .

  Thereafter, the recording medium P is fed into the fixing device 28 and is inserted into a contact area formed by press-contacting the heating roll 30 that is rotationally driven in the direction of the arrow and the pressure belt 40. At this time, the recording medium P is inserted so that the surface of the recording medium P on which the unfixed toner image is formed faces the surface of the heating roll 30. When the recording medium P passes through the contact area, heat and pressure are applied to the recording medium P, whereby an unfixed toner image is fixed on the recording medium P. After the fixing recording medium passes through the contact area, it is peeled off from the heating roll 30 by the peeling member 32 and discharged from the fixing device 28.

  In this way, the fixing process is performed, and the image is permanently fixed on the recording medium P. The recording medium P on which the color image has been fixed is unloaded to the discharge unit, and a series of color image forming operations is completed.

  In the present embodiment described above, the charging roll 2Y, the heating roll 30 of the fixing device 28, the primary transfer rolls 5Y to 5K, and the secondary transfer roll (secondary transfer means) 26 are rotated during the image forming operation. Along with this, the foreign matter on the surface is removed by the cleaning sheet 60 provided. And since the polyimide resin member which contains carbon black and has a predetermined volume resistivity is applied as the said cleaning sheet 60, compared with the case where it does not have this structure, the slidability and abrasion resistance with respect to each roll This improves the cleaning performance for a long period of time, prevents dust from adhering to the cleaning sheet 60 due to static electricity, and suppresses wear and scratches on each roll surface.

  Hereinafter, the polyimide resin member applied to the cleaning sheet 60 used in the image forming apparatus according to the embodiment will be described in detail.

The polyimide resin member contains carbon black and has a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm (desirably 10 ^{7 to} 10 ¹² Ω · cm, more desirably 10 ^{8 to} 10 ¹² Ω · cm. The following). By setting the volume resistivity within the above range, the strength of the member does not decrease, and dust adhesion due to static electricity accumulation is suppressed.

  The polyimide resin member may contain a conductive agent other than carbon black and have a volume resistivity in the above range. On the other hand, carbon black has advantages such as good dispersibility with respect to the polyimide resin, good surface smoothness of the member, and improved slidability and wear resistance as compared with a single resin member.

  Here, the volume resistivity is applied with a voltage of 100 V at 22 ° C. and 55% RH in accordance with JIS K6911 using the circular electrode shown in FIG. 6 (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). The value obtained from the current value after 30 seconds. FIG. 6 is a schematic plan view (a) and a schematic cross-sectional view (b) illustrating an example of a circular electrode, and the circular electrode includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′.

A test piece T is sandwiched between the cylindrical electrode portion C ′ and the ring-shaped electrode portion D ′ of the first voltage application electrode A ′ and the second voltage application electrode B ′, and the cylindrical shape of the first voltage application electrode A ′. The current I (A) that flows when the voltage V (V) is applied between the electrode portion C ′ and the second voltage application electrode B ′ is measured, and the volume resistivity ρv (Ωcm) of the member T ′ is calculated according to the following formula. ) Can be calculated. Here, in the following formula, t represents the thickness of the member T ′.
Formula: ρv = 19.6 × (V / I) × t

  In addition, the volume resistivity was measured using a circular electrode (HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd., outer diameter of cylindrical electrode portion C: 16 mm, inner diameter of ring-shaped electrode portion D: 30 mm, outer diameter: 40 mm), a voltage of 100 V is applied, and a current value after 30 seconds is obtained and calculated.

  On the other hand, acidic carbon black having a pH of 5 or less is suitably used as the carbon black blended in the polyimide resin member. The acidic carbon black can be produced by oxidizing the carbon black to give a carboxyl group, a quinone group, a lactone group, a hydroxyl group, or the like to the surface. This oxidation treatment is performed by an air oxidation method in which contact is made with air in a high temperature atmosphere to react, a method in which nitrogen oxide or ozone is reacted at room temperature (for example, 25 ° C.), and a low temperature after air oxidation at a high temperature. It can be performed by a method such as ozone oxidation under.

  Specifically, acidic carbon black having a pH of 5 or less can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Moreover, acidic carbon black can also be manufactured by the furnace black method which uses gas or oil as a raw material. Further, if necessary, after performing these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. Acidic carbon black can be produced by a contact method, but is usually produced by a closed furnace method. In the furnace method, only carbon black having a high pH and a low volatile content is usually produced, but the pH can be adjusted by subjecting it to the above-mentioned liquid phase acid treatment. For this reason, in the present invention, carbon black obtained by furnace method production and adjusted to have a pH of 5 or less by post-treatment is regarded as being included in acidic carbon black having a pH of 5 or less.

  The pH value of the acidic carbon black is desirably pH 5.0 or less, more desirably pH 4.5 or less, and further desirably pH 4.0 or less. Acidic carbon black having a pH of 5.0 or lower has an oxygen-containing functional group such as a carboxyl group, a hydroxyl group, a quinone group, and a lactone group on the surface, so that the dispersibility in the resin is good and good dispersion stability is obtained. The resistance variation of the member can be reduced.

  The pH of carbon black is determined by adjusting an aqueous suspension and measuring with a glass electrode. Further, the pH of the carbon black can be adjusted by conditions such as the treatment temperature and treatment time in the oxidation treatment step.

  Black carbon black preferably has a volatile component content of 3.5 to 25%, more preferably 3.5 to 20%, and still more preferably 3.5 to 15%. A dispersibility can be improved as content of the said volatile component is the said range.

  The content of this volatile component can be determined by the ratio of the organic volatile component (carboxyl group, hydroxyl group, quinone group, lactone group, etc.) that comes out.

  Two or more kinds of acidic carbon black may be contained. At this time, it is desirable that these carbon blacks have substantially different conductivity from each other, for example, those having different physical properties such as the degree of oxidation treatment, DBP oil absorption, specific surface area by BET method using nitrogen adsorption, etc. Use. When adding two or more types of carbon blacks having different electrical conductivity in this way, for example, after preferentially adding carbon black exhibiting high conductivity, carbon black having a lower electrical conductivity is added to reduce surface resistance. It is possible to adjust the rate. Even when two or more types of carbon black are contained in this way, the mixing and dispersion of both carbon blacks can be enhanced by using acidic carbon black as at least one of them.

  Specific examples of acidic carbon black include “Printex 150T” (pH 4.5, volatile content 10.0%) and “Special Black 350” (pH 3.5, volatile content 2.2%) manufactured by Degussa. "Special Black 100" (pH 3.3, volatile matter 2.2%), "Special Black 250" (pH 3.1, volatile matter 2.0%), "Special Black 5" (pH 3.0, Volatile content 15.0%), "Special Black 4" (pH 3.0, volatile content 14.0%), "Special Black 4A" (pH 3.0, volatile content 14.0%), "Special Black" 550 "(pH 2.8, volatile content 2.5%)," Special Black 6 "(pH 2.5, volatile content 18.0%)," Color Black FW200 "(pH 2.5, volatile content 20.0) %), “Color Black FW2” (pH 2.5, volatile content 16.5%), “Color Black FW2V” (pH 2.5, volatile content 16.5%), “MONARCH1000” (pH 2.5, volatile content) manufactured by Cabot Corporation 9.5%), “MONARCH 1300” manufactured by Cabot (pH 2.5, volatile content 9.5%), “MONARCH 1400” manufactured by Cabot (pH 2.5, 9.0% volatile content), “MOGUL-L” (PH 2.5, volatile matter 5.0%), “REGAL400R” (pH 4.0, volatile matter 3.5%) and the like.

  Acidic carbon black has better dispersibility in the resin composition due to the effect of the oxygen-containing functional groups present on the surface as described above compared to general carbon black. It is desirable to raise it. Thereby, since the amount of carbon black in the member increases, the effect of using acidic carbon black such as being able to suppress the in-plane variation of the electric resistance value can be more effectively exhibited.

  Carbon black may be included as carbon beads obtained by granulating carbon black.

  Here, the content of carbon black is desirably 10 to 30% by mass, and more desirably 18 to 30% by mass. As for the content of carbon black, a larger amount in the range in which the volume resistivity is expressed may be better in terms of wear resistance.

In addition, as the conductive agent other than carbon black, examples of the conductive material include carbon materials such as carbon fiber, carbon nanotube, and graphite, metals or alloys such as copper, silver, and aluminum, tin oxide, indium oxide, and oxide. Examples thereof include conductive metal oxides such as antimony, conductive titanium oxide, and SnO ₂ —In ₂ O ₃ composite oxide.

  Next, a polyimide resin member is demonstrated in detail with the suitable manufacturing method.

  A method for producing a polyimide resin member is a step of applying a polyimide precursor solution containing a conductive agent such as carbon black to the surface of a cylindrical or cylindrical core to form a polyimide precursor coating film (hereinafter referred to as “polyimide precursor”). The polyimide precursor coating film is dried and heated to form a polyimide resin film (hereinafter referred to as “polyimide resin film forming process”), and the polyimide resin. And a step of peeling the film from the columnar or cylindrical core (hereinafter referred to as “polyimide resin film peeling step”). Moreover, you may have another process as needed. The core body is not limited to a columnar or cylindrical shape, and may of course be a plate-like body.

-Polyimide precursor coating film formation process-
The polyimide precursor is synthesized by, for example, dissolving both in an aprotic polar solvent such as N-methylpyrrolidone, N, N-dimethylacetamide, acetamide, N, N-dimethylformamide. The concentration, viscosity and the like at the time of synthesis are selected and performed.

  In order to incorporate a conductive agent such as carbon black into the polyimide precursor solution, a known dispersion method such as a ball mill, a sand mill, or a roll mill can be used. There is also a method of synthesizing a polyimide precursor after dispersing a conductive agent such as carbon black in the monomer solution of either acid anhydride or diamine or both.

  Here, as for content of the electrically conductive agent in a polyimide precursor solution, it is desirable that it is 10-40 mass parts with respect to 100 mass parts of resin components, and 15-35 mass parts is especially desirable.

  In the polyimide precursor coating film forming step, a polyimide precursor solution is applied to the surface of a cylindrical or cylindrical core body to form a polyimide precursor coating film. As the coating method, a cylindrical or cylindrical core body is made of polyimide. Immersion coating method of immersing and pulling up in the precursor solution, flow coating method of discharging the polyimide precursor solution to the surface while rotating a cylindrical or cylindrical core, blade coating method of metalizing the film with a blade, etc. Existing known methods can be employed. In the above-described flow coating method or blade coating method, the coating is formed in a spiral shape by horizontally moving the coating portion, but the seam is naturally smoothed because the polyimide precursor solution dries slowly. In addition, “applying to the surface of a cylindrical or cylindrical core” means to apply to the surface of the side surface of the cylindrical core including the column and, if the surface has a layer, to the surface of the layer. To do.

  In the polyimide precursor coating film forming step, since the polyimide precursor solution has a higher viscosity than other solutions, the film thickness may be too thick than the desired value. In that case, the coating method which controls a film thickness with the annular body shown below is applicable, for example.

A coating method for controlling the film thickness by an annular body will be described with reference to the drawings.
FIG. 7 is a schematic cross-sectional view of an annular coating device provided with an annular body when stopped, and FIG. 8 is a schematic cross-sectional view of the annular coating device during coating. However, the figure shows only the main part, and other devices such as a core holding mechanism and a lifting device are omitted. In the following, “apply on the core” means to apply on the surface of the side surface of the core, and “apply by raising the core” is relative to the liquid level at the time of application. , “The core is stopped and the coating liquid level is lowered”.

  As shown in FIGS. 7 and 8, the annular coating method is a method in which the polyimide precursor solution 2 is put in the annular coating tank 6 and the core body 1 is passed from the lower part to the upper part for coating. An annular sealing material 7 made of a flexible plate material such as polyethylene or silicone rubber is provided at the bottom of the annular coating tank 6 so that the solution does not leak. Below the core body 1, a core body 1 </ b> B (this may be an intermediate body for which no member is manufactured) is attached.

  The core 1 is sequentially lifted from the lower part to the upper part of the annular coating tank 6, and the coating film 3 is applied to the surface by inserting the sealing material 7. On the liquid surface of the polyimide precursor solution 2, an annular body 4 provided with a circular hole 5 larger than the outer diameter of the core body 1 is installed in a freely movable state. Since the wet film thickness of the coating film 3 is determined by the gap between the core body 1 and the annular body 4, the inner diameter of the hole 5 is set in view of the desired film thickness. That is, the film thickness after the drying step is a product of the wet film thickness and the non-volatile concentration of the solution, and a desired wet film thickness is obtained from this.

  The annular body 4 may have a hollow structure, or legs and arms that support the annular body 4 may be provided on the outer peripheral surface of the annular body 4 or the coating tank 6 in order to prevent sinking. As a method of being installed in a freely movable state, there are a method of supporting the annular body 4 with a roll or a bearing, a method of supporting the annular body 4 with air pressure, in addition to a method of floating on the liquid surface of the polyimide precursor solution 2. .

  The material of the annular body 4 is selected from metals and plastics that are not affected by the solvent of the solution. Since the circular body 4 has low film thickness uniformity when the roundness of the inner diameter of the circular hole is low, the roundness specified in JIS-B0621 (1974) is preferably 20 μm or less, and is preferably 10 μm or less. Is more desirable. Of course, it is optimal that the roundness is 0 μm, but it is difficult in processing.

  The inner wall surface of the annular body 4 may have a stepped shape or a curved shape in addition to a linearly inclined surface as long as the lower part immersed in the solution is wide and the upper part is narrower than this. In order to process high roundness, a wall surface portion parallel to the core may be provided on the upper surface of the inner wall surface of the circular hole.

  When the core body 1 is lifted through the hole 5 of the annular body 4, friction resistance is generated between the core body 1 and the annular body 4 due to the presence of the polyimide precursor solution 2, and a lifting force acts on the annular body 4. The annular body 4 is slightly lifted. At this time, the annular body 4 moves so that the frictional resistance with the core body 1 becomes constant in the circumferential direction, and the gap between the annular body 4 and the core body 1 becomes constant. Becomes uniform. The pulling speed of the core body 1 is desirably about 0.1 to 1.5 m / min.

  The annular coating apparatus includes a core body holding means for holding the core body 1, a first moving means for moving the holding means in the vertical direction, and a second moving means for moving the annular coating tank 6 in the vertical direction. You may have.

  On the side surface of the annular coating tank 6, a plurality of supply pipes 8 for supplying the polyimide precursor solution are arranged, for example, at equal intervals along the circumferential direction. Although the number of the supply pipes 8 depends on the inner diameter of the annular coating tank 6, it is preferable that the number of the supply pipes 8 be approximately equal to 2-20. The solution is fed into the supply pipe 8 by appropriately connecting a tube. As a method of feeding the solution into the tank, there are a method of feeding by using pressurized air and a method of feeding by a pump. However, it is particularly desirable to use a radial screw pump in order to pump a high-viscosity solution at a constant flow rate without causing bubble entrainment or contamination.

  In addition, the cyclic | annular application | coating method using the cyclic | annular application | coating tank 6 has the advantage which requires less polyimide precursor solution 2 than a dip coating method.

-Polyimide resin film formation process-
In the polyimide resin film forming step, for the purpose of removing the solvent excessively remaining in the polyimide precursor coating film, drying is performed to such an extent that the coating film is not deformed even if left standing. The drying temperature is, for example, 80 to 180 ° C., and the drying time is about 10 to 60 minutes. At that time, when the solvent is extremely slow to dry, the polyimide precursor film is easily affected by gravity during drying, and dripping is likely to occur. In that case, it is desirable to dry the coated core body while rotating at about 10 to 60 rpm with the longitudinal direction being horizontal. In addition to heating, it is also effective to apply wind. The drying temperature is desirably increased stepwise or at a constant rate within a time period in order to reduce the dissolved gas in the solvent from becoming bubbles.

  In the polyimide resin film forming step, the polyimide resin film can be formed by heating the polyimide precursor coating film, for example, at 200 to 350 ° C. for about 10 to 60 minutes after the drying.

-Polyimide resin film peeling process-
After heating, a tubular polyimide resin member is obtained through a step of peeling the formed polyimide resin film from the cylindrical core. Then, the polyimide resin member is cut into a predetermined size. Further, when the thickness is insufficient, the cut ones may be bonded together.

  The tubular polyimide resin member (belt) can also be used as a transfer belt for electrophotography. Therefore, the cleaning sheet may be made of the same material as the transfer belt if the volume resistivity and thickness meet desired specifications. Further, as the cleaning sheet, an end material after the transfer belt is manufactured or a defective product that cannot be used as the transfer belt may be used. This can contribute to resource saving and cost reduction.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

<Example 1>
The following cleaning sheet, heating roll, and pressure belt are prepared, mounted on an apparatus (see FIGS. 4 and 5) having the same configuration as the fixing apparatus according to the above-described embodiment, and a recording medium on which toner is transferred is 30 per minute. The sheet was passed at the speed of the sheet, and a fixing test was conducted. As a result, even if a 50,000 sheet passing durability test was performed, the functions of the heating roll and the cleaning sheet were close to the initial state.

-Cleaning sheet-
In a polyimide precursor solution (trade name: Uimide KK, manufactured by Unitika, solid dispersion concentration: 18% by mass), carbon black (trade name: “Special Black 4 (pH 3. 0, volatile content 14.0%) ”(manufactured by Degussa) was added, and the mixture was stirred and mixed in a jet mill for 2 hours. The viscosity of this polyimide precursor solution was measured using a cone plate type viscometer (manufactured by Toki Sangyo Co., Ltd., model RE80U), using a rotor: 3 ° × R14, and at 25 ° C. and 55 ° C. under conditions of 5 rpm. It was 45 Pa · s when measured in a measurement environment of% RH.

An appropriate amount of the obtained polyimide precursor solution was applied onto a 50 cm square aluminum plate and stretched with a coating rod to form a coating film having a thickness of 8 mm. Note that a release agent (trade name: Sepacoat, manufactured by Shin-Etsu Chemical Co., Ltd.) is applied in advance to the aluminum plate. After the coating, heating and drying were performed at 120 ° C. for 30 minutes, and further, heating at 250 ° C. for 30 minutes and 300 ° C. for 30 minutes were performed for imidization reaction. After cooling to room temperature (for example, 25 ° C.), a gap was made at one end, and then the entire film was peeled off to obtain a polyimide resin sheet. The volume resistivity was 10 ⁸¹⁰ Ωcm, and the film thickness was 80 μm.

  The polyimide resin sheet was cut to a size of 316 × 25 mm. This was used as a cleaning sheet.

-Heating roll-
The outer surface of a cylindrical iron core having an outer diameter of 24 mm, a thickness of 0.5 mm, and a length of 310 mm is coated with silicone rubber (rubber hardness 33 degrees: JIS-A) as an elastic layer with a thickness of 3 mm, and further an elastic layer A PFA tube having a thickness of 30 μm was coated as a release layer on the surface. A halogen lamp having a maximum of 960 W (normally 600 W) is disposed inside the core as a heating source. This was used as a heating roll. The surface temperature of the heating roll is controlled at 175 ° C.

-Pressure belt-
A polyimide resin having a diameter of 30 mm, a thickness of 75 μm, and a length of 330 mm was used as a base material, and a perfluoroalkyl ether fluororesin (PFA) was applied to the outer peripheral surface of the base material to a thickness of 30 μm to form a surface layer. This was used as a pressure belt.

<Comparative Example 1>
A polyimide resin sheet was produced in the same manner as in Example 1 except that carbon black was not dispersed. The polyimide resin sheet had a film thickness of 80 μm and a volume resistivity of 10 ¹⁵ Ωcm. A fixing device was configured in the same manner as in Example 1 except that this polyimide resin sheet was cut and used as a cleaning sheet.
<Example 2>
In Example 1, 40 parts by mass of carbon black was added, and a polyimide resin sheet was prepared in the same manner. This polyimide resin sheet had a thickness of 80 μm and a volume resistivity of 10 ⁵ Ωcm. This polyimide resin sheet was cut to form a fixing device as a cleaning sheet in the same manner as in Example 1.

<Example 3>
First, the polyimide precursor solution used in preparation of the cleaning sheet in Example 1 was prepared.

  Separately, an aluminum cylinder having an outer diameter of 366 mm, a wall thickness of 10 mm, and a length of 900 mm was prepared, and the surface was roughened to Ra 1.0 μm by blasting with spherical alumina particles. A release agent (trade name: Sepacoat, manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the surface of the cylinder. And the polyester adhesive tape of width 10mm was wound around the axial direction both ends of the cylinder along the circumferential direction. This is to prevent the coating film from wrapping around the side surface of the core. This was used as a core.

  Next, using the polyimide precursor solution, a polyimide precursor coating film was formed on the surface (outer peripheral surface) of the core by an annular coating device (see FIGS. 7 and 8). At this time, an annular body having an outer diameter of 420 mm, an inner diameter of 367.1 mm at the smallest part of the circular hole, and a height of 50 mm was prepared and used. The inner wall of the annular body was linearly inclined, the inclination angle with respect to the vertical line was 10 °, and a 2 mm portion parallel to the core was formed at the upper end.

  On the other hand, an annular sealing material made of hard polyethylene resin having a thickness of 0.5 mm and having a hole with an inner diameter of 362 mm was attached to the bottom surface of an annular coating tank having an inner diameter of 450 mm and a height of 100 mm, and a core was passed through the center. The polyimide precursor solution was placed in an annular coating tank, and an annular body was placed. The polyimide precursor solution was supplied from supply pipes provided at eight locations on the side surface of the annular coating tank at equal intervals (45 ° intervals) in the circumferential direction.

  Subsequently, the core body was pulled up and coated while initially decelerating to 900 mm / min and then gradually to 600 mm / min. At that time, the annular body was lifted by 20 mm. Thereby, a coating film of a polyimide precursor solution having a wet film thickness of 500 μm was formed on the core.

  After coating, the core was placed on a turntable, leveled, and heated at 160 ° C. for 20 minutes while being rotated at 6 rpm, thereby drying the coating film of the polyimide precursor solution. As a result, a polyimide precursor film having a thickness of 150 μm was obtained. After drying, the adhesive tape was peeled off.

  Next, the core was placed in a vertical state and placed in a heating device, and reacted by heating at 200 ° C. for 30 minutes and at 300 ° C. for 30 minutes to form a polyimide resin film.

After cooling to room temperature of 25 ° C., the film was extracted from the core while blowing air between the core and the film to obtain an endless belt. The film thickness of the endless belt was 80 ± 1.5 μm. The endless belt was cut by 80 mm from both ends, and the center portion was cut to obtain an endless belt having a width of 360 mm. The obtained endless belt had a semiconductivity of 10 ⁸¹⁰ Ωcm when measured for volume resistivity, and could be used as an electrophotographic transfer belt.

  On the other hand, although the two end materials at the cut end had a non-uniform film thickness, the film thickness was 80 ± 2 μm for each 50 mm on the side close to the endless belt. When this was cut into a size of 306 × 20 mm, 9 to 12 polyimide resin sheets could be obtained. Similar to Example 1, this sheet could also be used as a cleaning sheet. Conventionally, the scrap was discarded, but it could be used in this way.

<Test example>
Here, the polyimide resin sheet obtained in Example 1 (Test Example 1), the polyimide resin sheet obtained in Comparative Example 1 (Test Example 2), and the polyimide resin sheet obtained in Example 2 (Test Example 3) Abrasion was compared. That is, in an environment of 23 ° C. and 55% RH, using a Taber abrasion tester (Part No. 812: manufactured by Coating Tester Co., Ltd.) equipped with # 2000 wrapping tape (manufactured by Fujifilm), it was rotated 5000 times at a load of 1 kg and a rotational speed of 70 rpm The amount of wear was measured. In the case of the sheet of Example 1, the amount of wear was 3 mg or less, but that of Comparative Example 1 was 5 mg, and that of Example 2 was 7 mg. In Example 1, the amount of wear was smaller.

  Also, the dust adhesion due to static electricity was evaluated as follows. 4 and 5 about the polyimide resin sheet (Test Example 1) obtained in Example 1, the polyimide resin sheet (Test Example 2) obtained in Comparative Example 1, and the polyimide resin sheet (Test Example 3) obtained in Example 2 A fixing sheet was mounted as a cleaning sheet 60, and the recording medium on which the toner was transferred was passed at a speed of 30 sheets per minute, and after a 20,000 sheet passing durability test. The adhesion of dust due to static electricity on the cleaning sheet after the paper passing durability test was confirmed with the eye. The results are shown in Table 1.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment. It is a schematic block diagram which shows the charging roll which concerns on embodiment. It is a perspective view which shows the charging roll which concerns on embodiment. 1 is a schematic configuration diagram illustrating a fixing device according to an embodiment. FIG. 3 is a perspective view illustrating a main part of the fixing device according to the embodiment. It is a schematic block diagram which shows an example of the measuring apparatus for measuring volume resistivity. It is a schematic cross-sectional view of an annular coating device provided with an annular body, It is a schematic sectional drawing of the cyclic | annular application | coating apparatus at the time of application | coating.

Explanation of symbols

1Y, 1M, 1C, 1K photoconductor 2Y, 2M, 2C, 2K charging roll 3Y, 3M, 3C, 3K laser beam 3 exposure device 4Y, 4M, 4C, 4K developing device 5Y, 5M, 5C, 5K primary transfer roll 6Y, 6M, 6C, 6K Photoconductor cleaning device 10Y, 10M, 10C, 10K Process cartridge 20 Intermediate transfer belt 20a Intermediate transfer member cleaning device 22 Drive roll 24 Support roll 26 Secondary transfer roll 28 Fixing device 30 Heating roll 32 Peeling member 40 Pressure belt 50 Pressure pad 52 Belt running guide 60 Cleaning sheet P Recording medium

Claims (9)

  A cleaning member comprising a polyimide resin member containing carbon black. A cleaning member comprising a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm.   An image forming apparatus comprising the cleaning member according to claim 1. An electrophotographic member;
A cleaning member disposed in contact with the electrophotographic member and cleaning the surface of the electrophotographic member, the cleaning member having a polyimide resin member containing carbon black;
An apparatus for electrophotography, comprising: An electrophotographic member;
A cleaning member disposed in contact with the electrophotographic member and cleaning the surface of the electrophotographic member, the cleaning member having a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm; ,
An apparatus for electrophotography, comprising:   An image forming apparatus comprising the electrophotographic apparatus according to claim 4. A fixing member;
A cleaning member disposed in contact with the fixing member and cleaning the surface of the fixing member, the cleaning member having a polyimide resin member containing carbon black;
And a fixing device. A fixing member;
A cleaning member disposed in contact with the fixing member and cleaning the surface of the fixing member, the cleaning member having a polyimide resin member having a volume resistivity of 10 ⁶ Ω · cm to 10 ¹³ Ω · cm;
And a fixing device.   An image forming apparatus comprising the fixing device according to claim 7.

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