JP5386907B2 - Fixing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a fixing device and an image forming apparatus.

  Conventionally, as a fixing device, for example, a rotatable heat fixing roll having a heating source, an endless pressure belt that is in contact with the heat fixing roll and rotationally moves together, and an inner side of the pressure belt are disposed. A pressing member that presses the pressure belt toward the heat fixing roll to form a contact portion between the pressure belt and the heat fixing roll, and allows the recording medium to pass through the contact portion. In addition, a configuration in which a toner image on the recording medium is fixed by heating and pressing is known.

As described above, in the fixing device, in order to reduce the friction coefficient μc between the pressure belt and the pressing member, a coating layer (low friction sheet) made of a glass fiber sheet coated and baked with a fluororesin, or a lipophilic agent treatment is conventionally performed. A low friction sheet using a fluororesin or a lipophilic agent is coated on the pressing member, and various modified silicone oils are used as a lubricant between the low friction sheet and the film tubular body. It is proposed to intervene (see, for example, Patent Documents 1 to 5).
Japanese Patent Application No. 10-213984 Japanese Patent Application 2001-56615 Japanese Patent Application No. 2001-249558 Japanese Patent Application 2001-66917 Japanese Patent Application 2001-34093

  An object of the present invention is to provide a fixing device that suppresses charging generated in a rotating body due to sliding with a sliding member.

The above problem is solved by the following means. That is,
The invention according to claim 1
A first rotating member;
A second rotating body disposed in contact with the first rotating body;
A pressing member disposed on the inner surface of the second rotating body and pressing the second rotating body from the inner surface of the second rotating body to the first rotating body;
A conductive sliding member interposed between the inner surface of the second rotating body and the pressing member, the conductive sliding member not being electrically connected to a power source ;
A conductive lubricant interposed between the inner surface of the second rotating body and the conductive sliding member;
A heating source for heating at least one of the first rotating body and the second rotating body;
A fixing device comprising:

The invention according to claim 2
The fixing device according to claim 1, wherein the conductive lubricant includes lubricating oil and conductive powder.

The invention according to claim 3
Before KiJun Namerayu is, fixing device according to claim 2, characterized in that the perfluoropolyether oil.

The invention according to claim 4
The fixing device according to claim 2, wherein the conductive powder is graphite-based conductive powder.

The invention according to claim 5
The fixing device according to claim 2, wherein the conductive powder is contained in an amount of 20 wt% to 80 wt% with respect to the lubricating oil.

The invention according to claim 6
The fixing device according to claim 1, wherein the conductive sliding member includes a heat resistant resin and conductive powder.

The invention according to claim 7 provides:
A latent image carrier,
A latent image forming means for forming a latent image on the surface of the latent image holding member;
Developing means for developing the latent image into a toner image using an electrophotographic developer;
Transfer means for transferring the toner image developed on the recording paper;
Fixing means for fixing the toner image on the recording paper;
With
The image forming apparatus according to claim 1, wherein the fixing unit is the fixing device according to claim 1.

According to the first aspect of the present invention, as compared with the case where this configuration is not provided, charging generated in the rotating body due to sliding with the sliding member is suppressed.
According to the invention which concerns on Claim 2, compared with another kind, deterioration of the lubricant by heat is suppressed.
According to the invention which concerns on Claim 3, compared with another kind, deterioration of the lubricant by heat is suppressed.
According to the invention which concerns on Claim 4, compared with another kind, the frictional resistance of a rotary body and a sliding member is reduced.
According to the fifth aspect of the present invention, the frictional resistance between the rotating body and the sliding member is reduced and generated between the rotating body and the sliding member as compared with the case where the content of the conductive powder is not taken into consideration. Charge is suppressed.
According to the invention which concerns on Claim 6, deterioration of the sliding member by heat | fever is suppressed compared with another kind.
According to the invention of claim 7, an image in which image disturbance is suppressed can be obtained as compared with the case where the present configuration is not provided.

  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 fixing device according to the first 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 driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 while being applied with tension. The intermediate transfer belt 20 is arranged from the first process cartridge 10Y to the fourth process. Endless running is performed in the direction toward the cartridge 10K.

  The support roller 24 is pressed in a direction away from the drive roller 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. Further, 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 driving roller 22.

  Since the first to fourth process cartridges 10Y, 10M, 10C, and 10K have substantially the same configuration, the first process cartridge that forms a yellow image disposed upstream in the running direction of the intermediate transfer belt here. 10Y 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 through 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 roller (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, each member of the first process cartridges 10M to 10Y is integrally formed in the housings 11M to 11Y (housing).

  Then, together with the first process cartridge 10Y, a primary transfer roller 5Y (primary transfer means) that transfers 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 roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (control means) (not shown).

  As shown in FIG. 2, the fixing device 28 includes a heating roll 30 (first rotating body) and a pressure belt 40 (second rotating body). The heating roll 30 and the pressure belt 40 face each other. Is provided. The pressure belt 40 is pressed against the heating roll 30 by a pressing pad 50 (pressing member) arranged inside the circumference thereof, and is pressed along the belt travel guide 52 while forming a contact portion while being in pressure contact with the heating roll 30. It is driven by receiving the driving force from 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 with a load of 1,000 gf) having a thickness of about 2 mm 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 μm or more and 50 μm or less. Of course, it is not restricted to these, You may 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 mm or more and 80 mm or less, 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.

  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. The resin substrate and the release layer are made of conventionally known materials.

  The pressing pad 50 (pressing member) has two pressing portions 51 a and 51 b having different hardness along the traveling direction of the recording medium P. The pressing portion 51a on the recording medium P entry side in the pressing pad 50 is made of a rubber-like elastic member, the pressing portion 51b on the recording medium P discharge side is made of a hard pressure applying member such as metal, and the pressure in the contact area is recorded on the recording medium. The recording medium P discharge side is made higher than the P entry side. The pressing portions 51a and 51b are supported by the holder 51c and press the heating roll 30 from the inner peripheral surface of the pressure belt 40 via the sliding sheet 60 (conductive sliding member). Conventionally, each time a rotating body such as a pressure belt is rotated, the rotating body is charged due to friction with a sliding member such as a sliding sheet, and image disturbance due to the charging occurs. In this embodiment, image disturbance is prevented by using a lubricant described later.

  A lubricant 62 is interposed between the sliding sheet 60 and the inner peripheral surface of the pressure belt 40. The lubricant 62 is supplied to the inner peripheral surface of the pressure belt 40 by, for example, a lubricant supply member 64 provided in a part of the belt traveling guide 52, and the inner periphery of the sliding sheet 60 and the pressure belt 40. It is interposed between the surfaces.

The conductive sliding sheet 60 is applied to the sliding sheet 60 (conductive sliding member). Here, the electrical resistance of the conductive sliding sheet 60 is preferably 10 ⁸ Ω / □ or less in terms of surface resistivity, and more preferably 10 ⁵ Ω / □ or less.

  The conductive sliding sheet 60 may be a sheet made of a conductive resin and imparted with conductivity. However, from the viewpoint of heat resistance, the conductive sliding sheet 60 is configured to include a heat resistant resin and conductive powder. It is good to apply the sheet | seat provided with. In addition, other additives may be added to the conductive sliding sheet 60.

  Examples of heat resistant resins include fluororesins, polyimide resins, polyamide resins, polyamideimide resins, polyetherimide resins, polyether salsaphone resins, polyether ketone resins, bismaleimide triazine resins, aramid resins, polyphenylene resins, polyphenylene sulfide resins, etc. Fluorine resin is desirable from the viewpoint of heat resistance and slidability.

  Examples of fluororesins include polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether (MFA), a copolymer of tetrafluoroethylene and perfluoroethyl vinyl ether (EFA), and tetrafluoroethylene. And perfluoroethylpropyl vinyl ether (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polyethylene / tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluoride ethylene (PCTFE) and vinyl fluoride (PVF) are desirable, and PTFE, MFA, EFA, or PFA is particularly desirable.

  As the fluororesin, a fluororesin subjected to electron beam cross-linking is preferably exemplified. Specifically, for example, polytetrafluoroethylene (PTFE) subjected to electron beam cross-linking is suitably exemplified. In addition, you may mix | blend and use the fluororesin (for example, electron beam bridge | crosslinking PTFE) to which the electron beam bridge | crosslinking was given to the non-crosslinked fluororesin (for example, non-crosslinked PTFE).

  The heat-resistant resin is a resin that does not melt or decompose even when the temperature rises (for example, the fixing temperature) of the apparatus.

Examples of the conductive powder (conductive filler) include carbon-based substances (carbon black, carbon beads granulated from carbon black, carbon fiber, graphite, etc.), metals or alloys (copper, silver, aluminum, or alloys thereof, etc.), Examples thereof include powders of conductive metal oxides (such as tin oxide, indium oxide, antimony oxide, SnO ₂ —In ₂ O ₃ composite oxide), conductive whiskers (such as potassium titanate).

  The average particle size of the conductive powder is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less. Here, this average particle diameter employs a laser diffraction scattering method in which a particle group (powder) is irradiated with laser light, and the average particle diameter is measured from the intensity distribution pattern of diffraction and scattered light emitted therefrom.

The electric resistance of the conductive powder is preferably 10 ⁸ Ωcm or less in terms of volume resistivity, more preferably 10 ⁵ Ωcm or less.

  The content of the conductive powder is desirably 20% by weight or more and 100% by weight or less with respect to the heat resistant resin, more desirably 25% by weight or more and 80% by weight or less, and further desirably 30% by weight or more and 60% by weight or less. % Or less. By setting the content within the above range, the frictional resistance between the pressure belt 40 (second rotating body) and the sliding sheet 60 (sliding member) is reduced as compared with the case where the content of the conductive powder is not taken into consideration. In addition, charging generated between the pressure belt 40 and the sliding sheet 60 is suppressed.

  The conductive sliding sheet 60 may be porous (having a large number of pores). Thereby, the retention capability of the lubricant 62 is improved. The conductive slide sheet 60 made porous is, for example, made by foaming a heat resistant resin, made porous by stretching the heat resistant resin uniaxially or biaxially, or sintered. Examples include molds.

When the porous conductive sliding sheet 60 is employed, a lubricant permeation preventing member (sheet member) for preventing the penetration of the lubricant 62 on the pressing pad 50 side is provided with the conductive sliding sheet 60 and the pressing pad. It is good to interpose between 50.
On the other hand, the conductive lubricant 62 is applied to the lubricant 62. Here, the electrical resistance of the conductive lubricant 62 is preferably 10 ⁸ Ω / □ or less in terms of surface resistivity, and more preferably 10 ⁵ Ω / □ or less.

  The conductive lubricant 62 may be made of a conductive lubricant and imparted with conductivity. However, from the viewpoint of heat resistance, the conductive lubricant 62 includes a lubricant (base oil) and conductive powder. Thus, it is preferable to apply a lubricant imparted with conductivity. In addition, other additives (for example, an antioxidant or the like) may be added to the lubricant 62.

  Lubricating oil (base oil) includes grease, silicone oil (for example, dimethyl silicone oil, dimethyl silicone oil with addition of organometallic salt, hindered amine addition dimethyl silicone oil, organometallic salt and hindered amine addition dimethyl silicone oil, methylphenyl silicone oil, amino Modified silicone oil, amino metal salt-added amino-modified silicone oil, hindered amine-added amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, sulfonic acid-modified silicone oil, etc.), fluorine oil (eg, fluorosilicone oil, perfluoropoly Ether oil). Among these, perfluoropolyether oil is preferable from the viewpoint of heat resistance and slidability.

Examples of the conductive powder (conductive filler) include carbon-based substances (carbon black, carbon beads granulated from carbon black, carbon fiber, graphite, etc.), metals or alloys (copper, silver, aluminum, or alloys thereof, etc.), Examples thereof include powders of conductive metal oxides (such as tin oxide, indium oxide, antimony oxide, SnO ₂ —In ₂ O ₃ composite oxide), conductive whiskers (such as potassium titanate).

  In particular, as the conductive powder, graphite-based conductive powder (for example, artificial graphite and natural graphite are available, and the shape is scaly graphite, flaky graphite, layered graphite, fluorinated graphite, etc.) is preferably applied. The Since this graphite-based conductive powder has cleavage properties, it is also cleaved even if it is interposed between the sliding sheet 60 to be slid and the inner peripheral surface of the pressure belt 40, so that the frictional resistance between members is reduced. .

  The average particle size of the conductive powder is preferably 1 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less. Here, this average particle diameter employs a laser diffraction scattering method in which a particle group (powder) is irradiated with laser light, and the average particle diameter is measured from the intensity distribution pattern of diffraction and scattered light emitted therefrom.

The electric resistance of the conductive powder is preferably 10 ⁸ Ωcm or less in terms of volume resistivity, more preferably 10 ⁵ Ωcm or less.

  The content of the conductive powder is desirably 20% by weight or more and 80% by weight or less, more desirably 25% by weight or more and 75% by weight or less, and further desirably 30% by weight or more and 70% by weight or less with respect to the lubricating oil. It is as follows. By setting the content within the above range, the frictional resistance between the pressure belt 40 (rotary body) and the sliding sheet 60 (sliding member) is reduced as compared with the case where the content of the conductive powder is not taken into consideration. Further, charging generated between the pressure belt 40 and the sliding sheet 60 is suppressed.

  The supply amount of the lubricant 62 may be an amount that can cover the sliding sheet surface. This is because the surplus moves to a location where there is no functional problem with use (supply felt or guide surface).

Here, the measurement method of the surface resistivity is performed as follows. Measurement is performed according to JIS K6991 using a circular electrode (for example, “HR probe” of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). A method for measuring the surface resistivity will be described with reference to the drawings. FIG. 3 is a schematic plan view (A) and a schematic cross-sectional view (B) showing an example of a circular electrode. The circular electrode shown in FIG. 3 includes a first voltage application electrode A and a plate-like insulator B. The first voltage application electrode A has a cylindrical electrode portion C and a cylindrical ring electrode having an inner diameter larger than the outer diameter of the cylindrical electrode portion C and surrounding the cylindrical electrode portion C at a constant interval. Part D is provided. The measuring object T is sandwiched between the cylindrical electrode part C and the ring electrode part D in the first voltage application electrode A and the plate insulator B, and the cylindrical electrode part C and the ring in the first voltage application electrode A are sandwiched. The current I (A) that flows when the voltage V (V) is applied between the electrode part D and the surface electrode D is measured, and the surface resistivity ρs (Ω / □) of the measuring object T is calculated by the following equation. Here, in the following formula, d (mm) indicates the outer diameter of the cylindrical electrode portion C, and D (mm) indicates the inner diameter of the ring-shaped electrode portion D.
Formula: ρs = π × (D + d) / (D−d) × (V / I)

On the other hand, the volume resistivity is measured in accordance with JIS K6991 using a circular electrode (for example, HR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). A method for measuring the volume resistivity will be described with reference to the drawings. The measurement is performed with the same device as the surface resistivity. However, the circular electrode shown in FIG. 3 includes a second voltage application electrode B ′ instead of the plate-like insulator B at the time of measuring the surface resistivity. An intermediate transfer belt T is sandwiched between the cylindrical electrode portion C and the ring electrode portion D in the first voltage application electrode A and the second voltage application electrode B ′, and the cylindrical electrode in the first voltage application electrode A The current I (A) that flows when the voltage V (V) is applied between the part C and the second voltage application electrode B is measured, and the volume resistivity ρv (Ωcm) of the measuring object T is calculated by the following equation. calculate. Here, in the following formula, t indicates the thickness of the measuring object T.
Formula ρv = 19.6 × (V / I) × t

  The surface resistivity and volume resistivity are circular electrodes (UR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd .: cylindrical electrode C outer diameter Φ16 mm, ring electrode portion D inner diameter Φ30 mm, outer diameter Φ40 mm). Is used to calculate the current value after application of voltage 500V for 10 seconds in an environment of 22 ° C./55% RH.

  Hereinafter, an image forming operation of the image forming apparatus according to the present embodiment will be described. The image forming operation will be described on behalf 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, for example, about −600 V or more and −800 V or less by the charging roller 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 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 roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a 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.

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

  Thus, the intermediate transfer belt 20 onto which the yellow toner image has been 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 the toner images of all the colors are transferred in a multiple manner through the first to fourth process cartridges are the intermediate transfer belt 20, the support roller 24 that contacts the inner surface of the intermediate transfer belt 20, and the image holding surface side of the intermediate transfer belt 20. To a secondary transfer portion constituted by a secondary transfer roller (secondary transfer means) 26 disposed in the position. On the other hand, the recording medium P is fed at a predetermined timing between the secondary transfer roller 26 and the intermediate transfer belt 20 via the supply mechanism, and a predetermined secondary transfer bias is applied to the support roller 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.

  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 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, in the fixing device 28, the conductive sliding sheet 60 (sliding member) is provided between the inner peripheral surface of the pressure belt 40 (second rotating body) and the pressing pad 50 (pressing member). ) And a conductive lubricant 62 is interposed between the inner peripheral surface of the pressure belt 40 (second rotating body) and the conductive sliding sheet 60 (sliding member). Therefore, a conductive path is formed by the conductive sliding sheet 60 and the conductive lubricant 62 interposed between the inner peripheral surface of the pressure belt 40 (second rotating body) and the pressing pad 50 (pressing member). The On the other hand, the pressure belt 40 and the conductive sliding sheet 60 slide with the rotation of the pressure belt 40 during fixing by the fixing device 28, and the pressure belt 40 is charged by friction (that is, the charge belt 40 is charged). Charged). The charge on the pressure belt 40 flows (escapes) from the pressure belt 40 through a conductive path formed by the conductive sliding sheet 60 and the conductive lubricant 62. For this reason, in the present embodiment, charging generated in the rotating body due to sliding with the sliding member is suppressed, and image disturbance caused by the charging is suppressed. As a result, an image in which the image disturbance is suppressed is obtained.

  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>
-Sliding sheet-
A solution in which 40 parts by weight of graphite as a conductive powder is added to 100 parts by weight (solid content) of polytetrafluoroethylene (PTFE resin) as a heat-resistant resin is filled into a mold, compression molded, and then the melting point or higher After heating and firing at a temperature of 1 to obtain a molded body, a sliding sheet having a thickness of 100 μm was obtained with a metal blade.
-Lubricant-
A lubricant was obtained by adding 50 parts by weight of graphite as conductive powder to 100 parts by weight of perfluoropolyether oil (PFPE oil) as a lubricant, stirring and mixing.

-Evaluation-
The obtained sliding sheet and lubricant were set in DCC400 manufactured by Fuji Xerox Co., Ltd., and the following evaluation was performed. The results are shown in Table 2.

-Image quality evaluation In the image quality evaluation, paper wrinkles (image quality 1) and the presence or absence of image omission due to electrostatic offset (image quality 2) were evaluated visually.

-Durability Durability was evaluated as follows. A printing test was carried out in the lateral direction of the paper while printing an image with four lines at regular intervals on plain paper A4 (the actual machine used was DCC400 (Fuji Xerox Co., Ltd.)). The durability was evaluated by confirming the appearance of the belt and sliding sheet (folded, scraped, broken, etc.) (density unevenness, etc.), paper changes (paper wrinkles, etc.).

・ Maximum driving torque The maximum driving torque was evaluated as follows. A torque meter was installed on the heating roll (H / R (heat roll)) shaft of the bench machine modified from the actual machine, and the torque required to drive the belt was measured.

<Examples 2 to 9, Comparative Example 1>
According to Table 1, a sliding sheet and a lubricant were produced and evaluated in the same manner as in Example 1 except that each component type and the amount thereof were changed. The results are shown in Table 2.

The details of the materials used in this example are as follows.
-Resin-
Polytetrafluoroethylene: PTFE resin, trade name: Teflon (registered trademark) 7-J (PTFE resin manufactured by Mitsui DuPont Fluorochemicals: Teflon (registered trademark) molding powder)
・ Electron beam cross-linked polytetrafluoroethylene: Electron beam cross-linked PTFE resin (manufactured by Hitachi Cable)

-Lubricant-
・ Perfluoropolyether oil: PFPE oil, trade name: demnum S100 (manufactured by Daikin Industries)
・ Dimethyl silicone oil (KF96: Shin-Etsu Silicone)

-Conductive powder-
Graphite: trade name UP-10 (manufactured by Nippon Graphite Co., Ltd.), average particle size 10 μm
・ Zinc oxide: Trade name Panatetra (Matsushita Amtec)
・ Carbon black (Denka Black: manufactured by Denki Kagaku Kogyo)

  From the results shown in Table 1, it can be seen that the present example is superior to the comparative example in terms of durability and maximum driving torque as well as image quality.

1 is a schematic configuration diagram illustrating an image forming apparatus according to an embodiment. 1 is a schematic configuration diagram illustrating a fixing device according to an embodiment. . FIG. 3 is a schematic plan view (A) and a schematic cross-sectional view (B) showing an example of a circular electrode.

Explanation of symbols

1Y, 1M, 1C, 1K Photoconductor 2Y, 2M, 2C, 2K Charging roller 3Y, 3M, 3C, 3K Laser beam 3 Exposure device 4Y, 4M, 4C, 4K Developing device 5Y, 5M, 5C, 5K Primary transfer roller 6Y, 6M, 6C, 6K Photoconductor cleaning device 10Y, 10M, 10C, 10K Process cartridge 20 Intermediate transfer belt 20a Intermediate transfer member cleaning device 22 Driving roller 24 Support roller 26 Secondary transfer roller 28 Fixing device 30 Heating roll 40 Pressure Belt 50 Press pad 52 Belt running guide 60 Sliding sheet (conductive sliding sheet)
62 Lubricant (conductive lubricant)
64 Lubricant supply member 100 Image forming apparatus P Recording medium

Claims (7)

A first rotating member;
A second rotating body disposed in contact with the first rotating body;
A pressing member disposed on the inner surface of the second rotating body and pressing the second rotating body from the inner surface of the second rotating body to the first rotating body;
A conductive sliding member interposed between the inner surface of the second rotating body and the pressing member, the conductive sliding member not being electrically connected to a power source ;
A conductive lubricant interposed between the inner surface of the second rotating body and the conductive sliding member;
A heating source for heating at least one of the first rotating body and the second rotating body;
A fixing device comprising:   The fixing device according to claim 1, wherein the conductive lubricant includes lubricating oil and conductive powder. Before KiJun Namerayu is, fixing device according to claim 2, characterized in that the perfluoropolyether oil.   The fixing device according to claim 2, wherein the conductive powder is graphite-based conductive powder.   The fixing device according to claim 2, wherein the conductive powder is contained in an amount of 20 wt% to 80 wt% with respect to the lubricating oil.   The fixing device according to claim 1, wherein the conductive sliding member includes a heat resistant resin and conductive powder. A latent image carrier,
A latent image forming means for forming a latent image on the surface of the latent image holding member;
Developing means for developing the latent image into a toner image using an electrophotographic developer;
Transfer means for transferring the toner image developed on the recording paper;
Fixing means for fixing the toner image on the recording paper;
With
The image forming apparatus according to claim 1, wherein the fixing unit is the fixing device according to claim 1.

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