JP2005171107A - Lubricant for electrophotography, lubricant-coating device, process cartridge and image-forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricant for electrophotography by which the amount of toner passing through a cleaning blade and remaining in a photoreceptor is reduced so as to be less than the conventional one regardless of the condition of the formed image even by using the toner formed into a spherical shape. <P>SOLUTION: The lubricant for the electrophotography to be coated on a latent image carrier to which the toner having ≥0.94 spherical degree is fed, is obtained by adding an inorganic additive satisfying the relation of 2Y/1,000≤X≤Y/10 [wherein, Y is a particle diameter (μm) of the toner; and X is a particle diameter (μm) of the inorganic additive] thereto. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

    The present invention relates to an electrophotographic lubricant, a lubricant application device, a process cartridge, and an image forming apparatus used in an electrostatic copying process in which development is performed by supplying toner to a latent image carrier that carries a latent image.

  In recent years, color image forming apparatuses using an electrophotographic method have become widespread, and further high definition of printed images has been demanded due to the fact that digitized images can be easily obtained. ing. As higher resolution and gradation of images are being studied, as a toner-side improvement that visualizes latent images, further spheroidization and smaller particle size have been studied in order to form high-definition images. ing.

  For example, a spherical shape having a specific particle size distribution as described in JP-A-11-12253, JP-A-2-284158, JP-A-3-181952, and JP-A-4-162048 is used. A pulverized toner, a method for obtaining a spheroidized or small-sized toner by suspension polymerization as described in JP-A-5-72808, or a method described in JP-A-9-15902. A binder resin and a colorant as described above are mixed in a solvent immiscible with water and dispersed in an aqueous solvent in the presence of a dispersion stabilizer to obtain a spherical or small particle size toner. A binder resin containing a partially modified resin as described in Kaihei 11-133668 and a colorant are mixed in an organic solvent, and dispersed in an aqueous solvent. Double addition It was performed, spheronized, and a method of obtaining a toner particle diameter has been proposed. With such toner, image quality and fluidity are improved.

  Further, in order to improve the image quality, it is necessary to remove as much toner as possible remaining on the surface of the photoreceptor after the toner image is transferred. In particular, as described above, since the spheroidized toner easily rolls, the toner enters between the cleaning blade and the photoconductor when cleaning the photoconductor (latent image carrier), passes through the cleaning blade, and remains on the photoconductor. In some cases, an abnormal image such as a ground cover may be caused, and various studies have been made to solve this problem.

  For example, in an electrophotographic image forming method having a cleaning member for cleaning toner remaining on a photoreceptor with an elastic rubber blade, zinc stearate as a lubricant in the toner is 0.01% or more and 0.5% based on the toner weight. An electrophotographic image forming method has been proposed in which the friction coefficient of the photosensitive member is reduced and the cleaning efficiency by an elastic rubber blade is increased by containing the toner (see, for example, Patent Document 1).

  Further, an electrostatic latent image is formed on the photosensitive member, and the electrostatic latent image is visualized as a toner image with a toner containing a release agent, and the toner image is recorded directly or via an intermediate transfer member. In an image forming apparatus for transferring a toner image transferred to a recording medium and fixing the toner image transferred to the recording medium to the recording medium, the coefficient of friction of the photosensitive member is reduced by applying zinc stearate as a lubricant to the photosensitive member, and using a cleaning blade An image forming apparatus that enhances cleaning efficiency has been proposed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 11-184340 JP 2002-287567 A

  However, in the invention of Patent Document 1, when zinc stearate is added to the toner, the distribution of zinc stearate on the photoreceptor becomes non-uniform depending on the state of the developed image, and in a portion where the amount of zinc stearate is small There is a problem that the toner passes through the elastic rubber blade and remains on the photosensitive member. Further, in the invention of Patent Document 2, when an image having a high image area ratio is formed by the image mode, the amount of the toner adhering to the toner increases and the distribution of zinc stearate on the photosensitive member becomes non-uniform. In a portion where the amount of zinc is small, there is a problem that the toner passes through the cleaning blade and remains on the photoreceptor. In common with the inventions of Patent Documents 1 and 2, since the amount of zinc stearate present in the photoconductor is small at the beginning of use of the new photoconductor, the toner remaining on the photoconductor is sufficiently removed. There is a problem that it cannot be done.

  The present invention has been made in view of these problems, and even when a spherical toner is used, the toner that passes through the cleaning blade and remains on the photoreceptor regardless of the state of the formed image. To provide an electrophotographic lubricant capable of reducing the amount more than before, and even when using a spheroidized toner, it passes through the cleaning blade regardless of the state of the image to be formed. A lubricant application device that can reduce the amount of toner remaining on the body more than before, and can maintain stable cleaning performance by supplying a sufficient amount of lubricant to the photoreceptor even at the first use. It is an object of the present invention to provide a process cartridge and an image forming apparatus.

In order to solve the above problems, the invention according to claim 1 is an electrophotographic lubricant applied to a latent image carrier to which toner having a circularity of 0.94 or more is supplied.
2Y / 1000 ≦ X ≦ Y / 10
Y: Toner particle size (μm)
X: Particle size of inorganic additive (μm)
An inorganic additive having the following relationship is added: a lubricant for electrophotography.

The invention according to claim 2 is the electrophotographic lubricant according to claim 1, wherein the inorganic additive is one or more selected from the group consisting of silica, titania, alumina, magnesia, zirconia, ferrite and magnetite. It is characterized by being a substance.

  The invention according to claim 3 is the electrophotographic lubricant according to claim 1 or 2, wherein the main component of the electrophotographic lubricant is a fatty acid metal salt or fluorine fine particles.

  According to a fourth aspect of the present invention, in the electrophotographic lubricant according to the third aspect, the addition amount of the inorganic additive is 1 to 30 wt% with respect to the main component.

  The invention according to claim 5 is a lubricant application device for applying the electrophotographic lubricant according to any one of claims 1 to 4 to a latent image carrier, wherein the lubricant application device includes: A brush-like roller that rotates about a rotation axis and contacts the latent image carrier, and the electrophotographic lubricant is a solid molded lubricant, the brush-like A lubricant application device, wherein a roller is configured to apply the electrophotographic lubricant to the latent image carrier by rubbing and scraping the lubricant molding. .

  According to a sixth aspect of the present invention, in the lubricant application apparatus according to the fifth aspect, the apparatus further comprises a latent image carrier new article detecting means for detecting the first use of the latent image carrier, and the initial application of the latent image carrier. The electrophotographic lubricant is applied to the latent image carrier when use is detected.

  According to a seventh aspect of the present invention, in the lubricant application device according to the sixth aspect, the coefficient of friction of the latent image carrier after the electrophotographic lubricant is applied is 0.4 or less. Features.

  The invention according to claim 8 is the lubricant application device according to any one of claims 5 to 7, further comprising pressing means for pressing the lubricant molded body against the brush roller with a pressure of 200 mN or more. It is characterized by.

  According to a ninth aspect of the present invention, in the lubricant applicator according to any one of the fifth to eighth aspects, the brush-like roller is rotated in a rotating direction of a rotating latent image carrier, and the brush The ratio of the peripheral speed between the roller and the latent image carrier is 0.8 to 1.2.

  According to a tenth aspect of the present invention, there is provided a charging means for charging a latent image carrier by bringing a charging member into contact with or close to the charging member, a developing means for developing toner by attaching a toner to the latent image of the latent image carrier, and a latent image carrier. 10. A device comprising: at least one cleaning unit that cleans toner remaining on the surface with a cleaning blade; a latent image carrier; and the lubricant application device according to claim 5. Process cartridge.

  According to an eleventh aspect of the present invention, there is provided an image forming apparatus comprising the process cartridge according to the tenth aspect.

  A twelfth aspect of the present invention is an image forming apparatus comprising the lubricant application device according to any one of the fifth to ninth aspects.

  According to a thirteenth aspect of the present invention, in the image forming apparatus according to the eleventh or twelfth aspect, the toner has a volume average particle diameter of 3 to 8 μm, and a ratio of the volume average particle diameter Dv to the number average particle diameter Dn. Dv / Dn is in the range of 1.00 to 1.40.

  According to a fourteenth aspect of the present invention, in the image forming apparatus according to any one of the eleventh to thirteenth aspects, the toner has a shape factor SF-1 in the range of 100 to 180, and the shape factor SF-2. Is in the range of 100-180.

  According to a fifteenth aspect of the present invention, in the image forming apparatus according to any one of the eleventh to fourteenth aspects, the toner has a substantially spherical shape.

  According to a sixteenth aspect of the present invention, in the image forming apparatus according to any one of the eleventh to fifteenth aspects, the shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3. R1 ≧ r2 ≧ r3), the ratio r2 / r1 between the major axis r1 and the minor axis r2 is in the range of 0.5 to 1.0, and the ratio r3 / r2 between the thickness r3 and the minor axis r2 Is in the range of 0.7 to 1.0.

  The invention according to claim 17 is the image forming apparatus according to any one of claims 11 to 16, wherein the toner includes at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and A toner material liquid in which a release agent is dispersed in an organic solvent is obtained by crosslinking and / or elongation reaction in an aqueous medium.

  Since the present invention is configured as described above, even when spherical toner is used, the amount of toner remaining on the photoreceptor through the cleaning blade regardless of the state of the formed image can be reduced. An electrophotographic lubricant, a lubricant applying device, a process cartridge, and an image forming apparatus that can be reduced more than ever can be provided.

  Further, it is possible to provide a lubricant application device, a process cartridge, and an image forming apparatus that can maintain a stable cleaning performance by supplying a sufficient amount of lubricant to the photoreceptor even at the first use.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate.

(Lubricant for electrophotography)
In this embodiment, silica is added to the electrophotographic lubricant as an inorganic additive that satisfies the following relationship.
2Y / 1000 ≦ X <Y / 10 Formula (1)
Y: Toner volume average particle diameter (μm)
X: particle diameter of silica (μm)

  As the inorganic additive to be added, inorganic substances such as silica, titania, alumina, magnesia, zirconia, ferrite, and magnetite can be used alone or in combination as long as the particle size satisfies the relationship of the formula (1). .

  Moreover, it is preferable that the addition amount with respect to the main component of the lubricant for electrophotography of an inorganic substance additive is 1-30 wt%. If the addition amount exceeds 30 wt%, it is not preferable because it becomes difficult to mold the electrophotographic lubricant into a solid form to form a lubricant molded body, and if the addition amount is less than 1 wt%, sufficient cleaning performance is obtained. Since it cannot be obtained, it is not preferable.

  In addition, the electrophotographic lubricant used in the molded lubricant is obtained by adding an inorganic additive, which will be described later, to zinc stearate, which is the main component, and then solidifying it. Here, as the main component of the lubricant for electrophotography, for example, lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, palmitic acid Melted and solidified fatty acid metal salts such as copper and zinc linolenate, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer A material obtained by molding a fluorine-based resin such as a polymer or a tetrafluoroethylene-oxafluoropropylene copolymer is preferable. In particular, a metal stearate having a large effect of reducing the friction of the photoreceptor and zinc stearate are more preferable.

  The toner used has a circularity of 0.94 or more. Here, the circularity is defined as (peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image), and becomes closer to 1 as the toner is closer to a true sphere. The toner having such a circularity can be controlled by applying strong agitation in the step of removing the organic solvent in the toner production method described later. A toner having a high degree of circularity can also be obtained by subjecting the toner produced by dry pulverization to a spheronization treatment. The spheroidizing treatment of toner produced by dry pulverization is roughly divided into a thermal method and a mechanical method. Examples of the thermal method include a method of performing spheronization treatment by spraying toner particles together with a hot air stream on an atomizer or the like. Further, as a mechanical method, there is a method in which a spheroidizing treatment is performed by adding toner to a mixer such as a ball mill together with a mixed medium such as glass having a low specific gravity and stirring the mixture. However, since the toner particles are aggregated by the thermal method and toner particles having a large particle diameter are generated, and fine particles are generated by the mechanical method, a second classification step is necessary.

  By adding the inorganic additive as described above to the electrophotographic lubricant, stable cleaning performance can be obtained. This mechanism can be explained as follows as a result of microscopic observation. FIG. 1 is an enlarged cross-sectional view of the main part in the vicinity of the contact portion between the cleaning blade and the photosensitive member when the electrophotographic lubricant of the present embodiment is applied, and FIG. 2 shows the electrophotographic lubricant of the present embodiment. FIG. 4 is an enlarged cross-sectional view of a main part in the vicinity of a contact portion between a cleaning blade and a photoreceptor when not applied. Referring to FIG. 1, a cleaning blade 15a is in contact with the surface of the photoconductor 5, and cleaning is performed by scraping off toner particles T remaining on the photoconductor 5 from the surface. Further, an electrophotographic lubricant is supplied to the photosensitive member 5 by a brush roller (not shown) on the upstream side in the rotational direction from the contact portion between the cleaning blade 15 a and the photosensitive member 5. The cleaning blade 15a has a convexly curved shape near the contact portion with the photoconductor 5, and the gap between the photoconductor 5 and the cleaning blade 15a is gradually narrowed toward the contact portion. Here, a portion that is narrower than the diameter of the toner particle T in the gap is defined as a region C.

  When the inorganic additive as described above is not added to the electrophotographic lubricant, as shown in FIG. 2, the toner particles T enter the region C and are pulled in the rotation direction of the photoreceptor 5. It passes through the cleaning blade 15a. That is, in this case, the toner particles T remain on the surface of the photoreceptor 5 without being cleaned. On the other hand, when the inorganic additive as described above is added to the electrophotographic lubricant, the inorganic additive particles having a smaller diameter than the toner particles T enter the region C as shown in FIG. Since the region C is filled with particles, the toner particles T can be prevented from entering the region C. As described above, the region C is filled with the inorganic additive particles, and plays the role of a bank for damming the toner particles T. That is, in this case, most of the toner particles T on the photoreceptor 5 are cleaned by the cleaning blade 15a (see Example 1).

(Image forming device)
Subsequently, an image forming apparatus using the electrophotographic lubricant of the present embodiment will be described with reference to the drawings as appropriate. In this example, a four-tandem system and a direct transfer system in which the transfer paper and the photosensitive member (latent image carrier) are in direct contact are illustrated. However, the electrophotographic lubricant is applied to the photosensitive member. As long as the electrophotographic lubricant is as described above, an image forming method such as an intermediate transfer belt method or a revolver developing method may be used.

  FIG. 3 is an overall configuration diagram of a full-color small printer. In an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 1, process cartridges 2 A, 2 B, 2 C, and 2 D each having a photoconductor 5 as an image carrier are connected to the apparatus main body 1. Each is detachably mounted. In addition, a transfer device 3 in which a transfer belt 3a is rotatably mounted in a direction indicated by an arrow A between a plurality of rollers is disposed in the approximate center of the device main body 1. The upper surface of the transfer belt 3a is arranged so that the photoreceptors 5 provided in the process cartridges 2A, 2B, 2C, and 2D are in contact with each other. In correspondence with the process cartridges 2A, 2B, 2C, and 2D, developing devices 10A, 10B, 10C, and 10D having different toner colors are arranged. A writing unit 6 is disposed above the process cartridges 2A, 2B, 2C, and 2D, and a duplex unit 7 is disposed below the transfer belt 3a. A reversing unit 8 is mounted on the left side of the apparatus main body 1 for reversing and discharging the transfer paper P after image formation or transporting it to the duplex unit 7. A fixing device 9 is provided between the transfer belt 3a and the reversing unit 8 for fixing the image on the transfer paper P onto which the image has been transferred. A reverse paper discharge path 20 is branched and formed on the downstream side of the fixing device 9 in the transfer paper conveyance direction, and the transfer paper P conveyed there can be discharged onto a paper discharge tray 26 by a pair of paper discharge rollers 25. It is composed. In addition, a sheet feeding unit including sheet feeding cassettes 11 and 12 that can store transfer sheets P of different sizes in two upper and lower stages is disposed at the lower part of the apparatus main body 1. Further, a manual feed tray 13 is provided on the right side surface of the apparatus main body 1 so as to be openable and closable in the direction indicated by the arrow B. The manual feed tray 13 is opened so that manual feeding can be performed therefrom.

  The developing devices 10A, 10B, 10C, and 10D have the same configuration, and are different only in the color of toner to be used. More specifically, the developing device 10A uses magenta toner, the developing device 10B uses cyan toner, the developing device 10C uses yellow toner, and the developing device 10D uses black toner. The developing devices 10A, 10B, 10C, and 10D include a developing roller facing the photosensitive member 5, a screw that conveys and stirs the developer, a toner concentration sensor, and the like. The developing roller is composed of an outer rotatable sleeve and an inner fixed magnet, and the toner is replenished from the toner replenishing device according to the output of the toner density sensor. In this embodiment, a two-component developer composed of toner and carrier is used as the developer. The carrier is generally composed of the core material itself, or a carrier provided with a coating layer on the core material. Examples of materials that can be used as the core material include ferrite and magnetite. The particle diameter of the core material is 20 to 65 μm, preferably about 30 to 60 μm. As the resin used for forming the coating layer, a styrene resin, an acrylic resin, a fluororesin, a silicone resin, a mixture thereof, or a copolymer can be used. A coating layer can be formed by a well-known method, for example, can be formed by apply | coating resin by the spraying method, the dipping method, etc. on the surface of a core material.

  The writing unit 6 includes four laser diode-type light sources prepared for each color, a pair of polygon scanners composed of a six-sided polygon mirror and a polygon motor, and an fθ lens disposed in the optical path of each light source. It is composed of a lens such as a long cylindrical lens or a mirror. Laser light emitted from the laser diode is deflected and scanned by a polygon scanner and irradiated onto the photosensitive member 5.

  The duplex unit 7 includes a pair of conveyance guide plates 45a and 45b and a plurality of (four sets in this example) conveyance rollers 46 that form a pair. In the double-sided image formation mode in which images are formed on both sides of the transfer paper P, the transfer paper P that has been formed on one side and conveyed to the reversal conveyance path 54 of the reversing unit 8 and conveyed switchback is received. Is conveyed in the direction of the paper feed unit.

  The reversing unit 8 includes a plurality of paired transport rollers 60 and a reverse transport path 54 formed by a plurality of paired transport guide plates 61. As described above, the transfer paper when forming a double-sided image is used. The sheet P is turned upside down and carried out to the duplex unit 7, the transfer paper P after image formation is discharged out of the apparatus in the same direction, or the sheet is turned upside down and discharged out of the apparatus.

  The paper feeding unit includes paper feeding cassettes 11 and 12, and separation paper feeding units 55 and 56 for separating and feeding the transfer paper P one by one are provided in the vicinity of the takeout port of the transfer paper P, respectively. Yes.

(Process cartridge)
The process cartridges 2A, 2B, 2C, and 2D are units having the same configuration, the process cartridge 2A forms an image corresponding to magenta, the process cartridge 2B forms an image corresponding to cyan, and the process cartridge 2C forms an image corresponding to the yellow color, and the process cartridge 2D forms an image corresponding to the black color. FIG. 4 is a schematic diagram showing the configuration of the process cartridge. As shown in FIG. 4, the process cartridges 2 </ b> A, 2 </ b> B, 2 </ b> C, and 2 </ b> D have a charging unit 14 that contacts a charging roller 14 a that is a charging member to charge the photosensitive member 5, and a photosensitive member by contacting the photosensitive member 5. A cleaning means 15 having a cleaning blade 15a for cleaning toner remaining on the toner 5, a rotating photosensitive member 5 on which an electrostatic latent image is formed, and a rotational axis arranged in parallel with the rotational axis of the photosensitive member 5. The lubricant application device 17 is provided with a brush-like roller 17 a that is rotated and applies the electrophotographic lubricant to the photoreceptor 5.

  The process cartridge includes at least one of a charging unit, a developing unit that develops toner by attaching the toner to the latent image of the photosensitive member 5, and a cleaning unit, and the photosensitive member 5 and the lubricant application device 17. As long as it is detachably attached to the main body 1, it is not limited to that of the present embodiment. By configuring the process cartridge in this way, it is possible to extend the life of the photosensitive member 5 accommodated in the process cartridge, and when maintenance is required, the process cartridge may be replaced. improves.

  The charging roller 14a of the charging unit 14 is conductive and applies a DC and / or AC voltage to apply a charge on the photoconductor 5 to charge the photoconductor 5. A charging roller cleaning brush 14b for cleaning the surface of the charging roller 14a is in contact with the charging roller 14a.

  The cleaning means 15 is configured to move the toner scraped off from the surface of the photoreceptor 5 by the cleaning blade 15a to the toner transport auger 15d by the rotation of the brush-like roller 17a. The waste toner collected in the toner transport auger 15d is transported to the waste toner storage unit 18 shown in FIG. 3 by the rotation of the toner transport auger 15d.

(Lubricant application device)
The lubricant application device 17 is incorporated in the process cartridges 2A, 2B, 2C, and 2D, and includes a lubricant molded body 17b obtained by molding the above-described electrophotographic lubricant into a long rectangular parallelepiped shape, and a lubricant molded body 17b. A brush roller 17a applied to the surface of the photoreceptor 5, a brush roller scraper 17c for removing the toner adhering to the brush roller 17a, and a lubricant molded body 17b. A pressure spring 17d that presses the brush-like roller 17a with a predetermined pressure, and a latent image carrier new article detecting means (not shown) that detects whether the photosensitive member 5 is used for the first time (whether it is a new article). I have. In this embodiment, the lubricant application device 17 is incorporated in the process cartridges 2A, 2B, 2C, and 2D, but may be incorporated directly in the apparatus main body 1.

  The brush roller 17 a has a shape extending in the direction of the rotation axis of the photosensitive member 5. The pressure spring 17d urges the lubricant molded body 17b against the brush-like roller 17a so that almost all of the lubricant molded body 17b can be used up. The lubricant molded body 17b is scraped by the brush-like roller 17a, and the thickness thereof decreases with time. However, since the pressure is applied by the pressure spring 17d, the lubricant-molded body 17b is always in contact with the brush-like roller 17a. Then, the electrophotographic lubricant is scraped off from the molded lubricant 17 b, and the electrophotographic lubricant thus scraped off is applied to the photoreceptor 5.

  Here, the molded lubricant 17b is pressed against the brush-like roller 17a by a pressure spring 17d including its own weight with a pressure of 200 mN or more. As the pressing force increases, the amount of electrophotographic lubricant that the brush roller 17a is scraped off from the molded lubricant 17b increases, and the amount of electrophotographic lubricant applied to the photoreceptor 5 increases. In addition, the coefficient of friction of the photosensitive member 5 can be efficiently reduced.

  Further, the brush roller 17a is rotated in the rotating direction of the photoconductor 5 at the portion in contact with the photoconductor 5, and the peripheral speed ratio between the brush roller 17a and the photoconductor 5 (photoconductor peripheral speed / brush shape). The circumferential speed of the roller) is 1.0. By rotating the brush roller 17a in the circumferential direction, the electrophotographic lubricant adhering to the brush roller 17a can be applied without giving an impact to the photoreceptor 5. That is, immediately after application of the electrophotographic lubricant by the brush roller 17a, the electrophotographic lubricant is not a coating covering the photoconductor 5, but cleaning is performed when the photoconductor 5 passes the cleaning blade 15a. The electrophotographic lubricant becomes a film that covers the photoreceptor 5 by being spread by the pressing force of the blade 15a. Therefore, in order to apply the electrophotographic lubricant without giving an impact to the photoconductor 5, the brush roller 17 a is rotated in the direction around the photoconductor 5. Further, the peripheral speed ratio between the brush roller 17a and the photoconductor 5 (photoconductor peripheral speed / peripheral speed of the brush roller) is preferably in the range of 0.8 to 1.2. When the peripheral speed ratio is less than 0.8, the supply amount of the electrophotographic lubricant decreases, and when it exceeds 1.2, the photoreceptor 5 may be damaged by impact, and the life of the photoreceptor 5 may be shortened. is there. Further, in order to supply the electrophotographic lubricant from the brush roller 17a to the photoconductor 5 with a small impact, the peripheral speed ratio between the brush roller 17a and the photoconductor 5 is in the range of 1.0 to 1.1. It is more preferable.

(Latent image carrier new article detection means)
The latent image carrier new article detection means includes a storage means such as an IC chip for storing the number of times the photoreceptor 5 is used. The latent image carrier new article detecting means rotates the brush roller 17a for a predetermined time with respect to the apparatus main body 1 when the stored number of use times is zero (at the first use), so that the new photoconductor 5 is used for electrophotography. Issue a command to apply lubricant. Here, the latent image carrier new article detecting means is configured to store the number of times of use of the photosensitive member 5 in the IC chip. For example, the engagement with the apparatus main body 1 is released only at the first use. The first use may be detected by providing a simple member on the process cartridge 2A and the engagement state of this member is confirmed, or it may be configured as software stored in the lubricant application device 17.

  At the first use, the coefficient of friction of the photoreceptor 5 after the electrophotographic lubricant is applied according to the instruction from the latent image carrier new article detecting means is 0.4 or less, preferably 0.2 or less. By setting the friction coefficient of the photoconductor 5 to 0.4 or less, the interaction between the photoconductor 5 and the toner is reduced, the toner on the photoconductor 5 is easily separated, and the transfer rate can be increased. Further, it is possible to suppress an increase in friction between the cleaning blade 15a and the photosensitive member 5 and improve the cleaning efficiency. In particular, in the case of toner having a high degree of circularity, the toner easily rolls on the photoconductor 5, so that the occurrence of poor cleaning can be suppressed. Further, the occurrence of cleaning failure due to long-term use can be suppressed by increasing the transfer rate and reducing the amount of toner to be cleaned. On the other hand, if the friction coefficient is less than 0.1, the amount of toner slipping too much between the cleaning blade 15a and the toner passing through the cleaning blade 15a on the photosensitive member 5 increases, resulting in poor cleaning (experiment). See Example 1).

  Further, at the first use, the application time of the electrophotographic lubricant according to the instruction from the latent image carrier new article detection means, that is, the time for rotating the brush roller 17a is 100 s or more. By setting the coating time to 100 s or longer, the friction coefficient of the new photoconductor 5 can be lowered to a saturated state (0.2 or less) (see Example 2).

  Here, at the first use, the charging bias and the developing bias may be turned off when applying the electrophotographic lubricant according to the instruction from the latent image carrier new article detecting means, but the toner is applied to the brush roller 17a. In order to more efficiently apply the electrophotographic lubricant to the photoconductor 5 without adhering, the photoconductor 5 is prevented from causing toner input to the brush roller 17a due to background contamination during application of the electrophotographic lubricant. Alternatively, a background potential may be applied to the developing sleeve to prevent the background stain from occurring.

  In this way, at the first use, by applying the electrophotographic lubricant according to the instruction of the latent image carrier new article detecting means, the new photoreceptor 5 in the state where the electrophotographic lubricant is not applied is applied. A sufficient amount of electrophotographic lubricant can be applied. In this way, when the electrophotographic lubricant is applied to the photoconductor 5 at the first use, and the friction coefficient of the photoconductor 5 is lowered and becomes saturated, the toner adheres to the brush roller 17a. However, it is possible to supply the electrophotographic lubricant to the photosensitive member 5 by the brush roller 17a as long as the low friction coefficient can be maintained. Also, since the molded lubricant 17b is soft and brittle, the new molded lubricant 17b is provided with a slightly harder coating layer than the internal electrophotographic lubricant. This coating layer can be efficiently removed by applying. In addition, if toner adheres to the brush-like roller 17a, the application efficiency of the electrophotographic lubricant from the lubricant molded body 17b to the photosensitive member 5 decreases, and the toner does not adhere to the portion to which the toner has adhered. In the portion, uneven application of the electrophotographic lubricant occurs on the photosensitive member 5. However, since the electrophotographic lubricant can be uniformly applied to the photoconductor 5 by applying the electrophotographic lubricant at the first use as in the present embodiment, the friction of the photoconductor 5 The coefficients are uniform, the transfer rate from the toner image on the photoconductor 5 to the transfer paper P is uniform, and an image with a uniform density is obtained. Further, by applying a lubricant for electrophotography at the first use and reducing the coefficient of friction of the photosensitive member 5, even a toner having a small particle size and high circularity is cleaned without reducing the cleaning efficiency. be able to.

(Operation of image forming apparatus)
Next, the operation of the image forming apparatus in image formation will be described with reference to FIGS. When the image forming operation is started, each photoconductor 5 rotates in the clockwise direction. The surface of each photoreceptor 5 is uniformly charged by the charging roller 14a. Then, laser light corresponding to a magenta image is written on the photosensitive member 5 of the process cartridge 2A by the writing unit 6, and laser light corresponding to a cyan image is applied to the photosensitive member 5 of the process cartridge 2B. The body 5 is irradiated with a laser beam corresponding to a yellow image, and the photosensitive member 5 of the process cartridge 2D is irradiated with a laser beam corresponding to a black image, thereby forming a latent image corresponding to the image data of each color. The Each latent image reaches the position of the developing devices 10A, 10B, 10C, and 10D by the rotation of the photosensitive member 5, and is developed with each of the magenta, cyan, yellow, and black toners to obtain a four-color toner image. Become.

  On the other hand, the transfer paper P is fed from the paper feed cassettes 11 and 12 of the paper feed unit, and the toner formed on each photoconductor 5 by the registration roller pair 59 provided immediately before the transfer belt 3a. It is conveyed at the same timing as the image. The transfer paper P is charged to a positive polarity by a paper suction roller 58 disposed in the vicinity of the entrance of the transfer belt 3a, and thereby electrostatically attracted to the surface of the transfer belt 3a. Then, while the transfer paper P is conveyed while being adsorbed to the transfer belt 3a, magenta, cyan, yellow and black toner images are sequentially transferred to form a four-color full color toner image. The At this time, a part of the toner is not transferred and remains attached on the photoreceptor 5. The transfer paper P is melted and fixed by applying heat and pressure by the fixing device 9, and then passes through the paper discharge system corresponding to the designated mode, and then the paper discharge tray 26 at the top of the apparatus main body 1. When the paper is discharged straight from the fixing device 9 and straightly discharged through the reversing unit 8 or when the double-sided image forming mode is selected, the reversing conveyance path in the reversing unit 8 described above. The image is formed on the back surface in the image forming unit provided with the process cartridges 2A, 2B, 2C, and 2D. It will be discharged later.

  On the other hand, the photoconductor 5 separated from the transfer belt 3a continues to rotate, and the brush roller 17a applies the electrophotographic lubricant scraped from the lubricant molding 17b to the photoconductor 5. The applied electrophotographic lubricant is pressed against the photoconductor 5 when the toner remaining on the photoconductor 5 is cleaned by the cleaning blade 15 a, thereby forming a film on the photoconductor 5.

  In the subsequent image formation, the above-described image forming process is repeated. However, since the electrophotographic lubricant film formed on the photosensitive member 5 is very thin, charging by the charging means 14 is not hindered. Thereafter, the toner image developed again on the photosensitive member 5 is transferred onto the transfer paper P in a state of being attracted to the transfer belt 3a.

(Operation of new latent image carrier detection means)
Next, the operation of the latent image carrier new article detecting means will be described with reference to FIG. FIG. 5 is a flowchart showing the operation of the latent image carrier new article detecting means. When the power of the apparatus main body 1 is turned on (S1), the latent image carrier new article detecting means refers to the number of uses of the photoconductor 5 stored in the IC chip and determines whether or not the first use (the number of uses is 0). That is, it is determined whether the photoconductor 5 is new (S2). If it is determined in S2 that the photoconductor 5 is used for the first time (Y), the process branches to S3, and the latent image carrier new article detecting means applies electrophotography to the new photoconductor 5 with respect to the apparatus main body 1. Issue a command to apply lubricants. In response to this command, the apparatus main body 1 drives the photosensitive member 5 for the predetermined time (100 s or more) described above to rotate the brush roller 17a, thereby supplying the electrophotographic lubricant from the molded lubricant 17b. By scraping and applying to the photoconductor 5, the friction coefficient of the photoconductor 5 is reduced to 0.4 or less (S3). In S3, it is desirable that the developing roller and the transfer belt 3a be operated at the same linear speed or separated from the photosensitive member 5 at the same time. When application of the electrophotographic lubricant is thus completed, the process proceeds to S4, and a normal warm-up operation is performed. If it is determined in S2 that the photoconductor 5 is not used for the first time (N), S3 is skipped and a normal warm-up operation is performed (S4).

(toner)
A toner having a volume average particle diameter Dv of the toner used in the image forming apparatus of this embodiment is 8 μm or less at most because a smaller one can improve fine line reproducibility. However, since the developing property and the cleaning property are lowered when the particle size is small, at least 3 μm is preferable. Further, if the particle size is less than 3 μm, the toner having a small particle diameter that is difficult to be developed on the surface of the carrier or the developing roller increases. This is not preferable because an abnormal image such as fogging is formed.

  The particle size distribution represented by the ratio (Dv / Dn) of the volume average particle size Dv to the number average particle size Dn is preferably in the range of 1.00 to 1.40. By sharpening the particle size distribution, the toner charge amount distribution can be made uniform. When Dv / Dn exceeds 1.40, the toner charge amount distribution is wide and the amount of reversely charged toner increases, making it difficult to obtain a high-quality image. If Dv / Dn is less than 1.00, it is difficult to produce and it is not practical. The particle size of the toner is 50,000 by using a Coulter Counter Multisizer (manufactured by Coulter Co., Ltd.) and selecting an aperture having a measurement hole size of 50 μm corresponding to the particle size of the toner to be measured. It is obtained by measuring the average particle size of the particles.

The toner preferably has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. 6A and 6B are schematic diagrams schematically illustrating the shape of the toner. FIG. 6A is a diagram for explaining the shape factor SF-1, and FIG. 6B is a diagram for explaining the shape factor SF-2. The shape factor SF-1 represents the ratio of the roundness of the toner shape and is represented by the following formula (2). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (2)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.

The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (3). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100π / 4) Expression (3)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent. Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), and introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) for analysis. And calculated.

  When the shape of the toner is close to a sphere, the contact between the toner and the toner or the photoconductor 5 becomes a point contact, so that the adsorbing force between the toners becomes weak, and as a result, the fluidity increases, and the toner and the photoconductor 5, the transfer rate is increased, and the reversely charged toner is easily collected by the temporary holding device.

  The toner shape factors SF-1 and SF-2 are preferably 100 or more. In addition, as SF-1 and SF-2 increase, the amount of reversely charged toner increases, the toner charge amount distribution increases, and the load on the temporary holding device increases. For this reason, SF-1 preferably does not exceed 180, and SF-2 preferably does not exceed 180.

  7A and 7B are schematic views showing the outer shape of the toner. FIG. 7A is an appearance of the toner, and FIG. 7B is a cross-sectional view of the toner. In FIG. 7A, the X axis represents the longest axis r1 of the longest axis of the toner, the Y axis represents the shortest axis r2 of the next longest axis, and the Z axis represents the thickness r3 of the shortest axis. ≧ Short axis r2 ≧ Thickness r3

  The toner has a major axis / minor axis ratio (r2 / r1) of 0.5 to 1.0 and a thickness / minor axis ratio (r3 / r2) of 0.7 to 1.0. It has a substantially spherical shape. If the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, it is not preferable because the charge amount distribution becomes wider because it approaches an indefinite shape. If the ratio between the thickness and the minor axis (r3 / r2) is less than 0.7, it is not preferable because it approaches an indeterminate shape and the charge amount distribution becomes wide. In particular, a ratio of thickness to minor axis (r3 / r2) of 1.0 is preferable because the toner has a substantially spherical shape and the charge amount distribution becomes narrow. The size of the toner so far was measured with a scanning electron microscope (SEM) while changing the angle of the field of view and observing in situ.

  The shape of the toner can be controlled by the manufacturing method. For example, the toner by the dry pulverization method has an irregular shape in which the toner surface is uneven and the toner shape is not constant. Even this dry pulverized toner can be made into a nearly spherical toner by applying mechanical or thermal treatment. In many cases, a toner produced by forming droplets by a suspension polymerization method or an emulsion polymerization method has a smooth surface and a nearly spherical shape. Moreover, it can be made into an ellipse by stirring in the middle of the reaction in a solvent and applying a shearing force.

  The toner suitably used in the image forming apparatus of the present embodiment includes a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent, It is obtained by crosslinking and / or elongation reaction in an aqueous solvent. A schematic configuration of the toner thus manufactured is shown in FIG. FIG. 8 is a schematic configuration diagram of the toner. The toner consists of a binder resin consisting of a crosslinked polyester prepolymer and polyester, and a colorant, and an external additive that imparts fluidity is externally added to the toner surface. In addition, the chargeability of the toner is controlled. It may contain a charge control agent, a release agent that improves the releasability with respect to the fixing device, and the like. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound.

  Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.), alkylene ether glycol (diethylene glycol). , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.), alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.), bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.), alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol, Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. As trihydric or higher polyhydric alcohol (TO), trihydric or higher polyhydric aliphatic alcohol (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.), trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.), alkylene oxide adducts of the above trivalent or higher polyphenols, and the like.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.), alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.), aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.

  The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.), alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ), Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.), araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.), isocyanates, the above polyisocyanates as phenol derivatives, oximes, Examples thereof include those blocked with caprolactam and the like and combinations of two or more thereof.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.) and alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.) and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.). Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  Further, the urea-modified polyester may contain a urethane bond as well as a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Solvents that can be used include aromatic solvents (toluene, xylene, etc.), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), esters (ethyl acetate, etc.), amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2,000 to 15,000, preferably 2,000 to 10,000, and more preferably 2,000 to 8,000. When it exceeds 20,000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. A range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ^-3 ~2μm, it is particularly preferably 5 × 10 ^-3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.

Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when agitation and mixing are performed using an average particle diameter of both fine particles of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

(Toner production method)
Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.

1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The amount of the organic solvent used is usually 0 to 300 parts by weight, preferably 0 to 100 parts by weight, and more preferably 25 to 70 parts by weight with respect to 100 parts by weight of the polyester prepolymer.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone, or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2,000 parts by weight, preferably 100 to 1,000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2,000 parts by weight, it is not economical.

  Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added. As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

  In addition, examples of the cationic surfactant include aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. , Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 (Daikin Industries) Manufactured), MegaFuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footgent F-300 (Neos), and the like.

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.). In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

  As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1,000 to 30,000 rpm, preferably 5,000 to 20,000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  FIG. 9 shows experimental results showing that stable cleaning performance can be obtained by adding the inorganic additive as described above to the electrophotographic lubricant. FIG. 9 shows a toner having a volume average particle diameter of 5 μm manufactured by the above-described toner manufacturing method, and 30 wt% silica added to the main component zinc stearate in the lubricant molding 17b. The contamination of the charging roller 14a when the particle diameter of silica was changed in various ways was evaluated. Here, the contamination of the charging roller 14a represents the amount of toner remaining on the surface of the photoconductor 5 without being cleaned by the cleaning blade 15a, and is considered to be a characteristic representing the cleaning performance of the image forming apparatus. The dirt rank 5 indicates a state where there is no dirt, and the dirt on the charging roller 14a increases as the rank decreases. In this evaluation, if the rank is 4 or more (ranks 4 and 5), no defect occurs in the image transferred to the transfer paper P. Therefore, it can be seen from FIG. 9 that when the particle diameter of the silica to be added is in the range of 0.01 to 0.5 μm, no defect occurs in the image. A similar experiment was performed using toners having different particle diameters, but stable cleaning performance can be obtained by adding silica having a particle diameter satisfying the formula (1) to the lubricant molded body 17b.

Experimental example 1

  FIG. 10 shows the number of sheets to be passed when the A4 size transfer sheet P on which an image with an image area ratio of 5% is passed is passed through a new photoreceptor 5 to which no electrophotographic lubricant is applied. The relationship of the friction coefficient of 5 is shown. According to this graph, the friction coefficient of the new photoreceptor 5 is 0.4 or more, but gradually decreases as the number of transferred sheets increases, and saturates at about 0.2 or less from about 100 sheets. Accordingly, it is preferable that the coefficient of friction of the photoreceptor 5 after the electrophotographic lubricant is applied according to the instruction from the latent image carrier new article detecting means is 0.4 or less, preferably 0.2 or less. I understand.

  Here, the friction coefficient of the photosensitive member 5 was measured by the Euler belt method as follows. FIG. 11 is a diagram for explaining a method of measuring the friction coefficient of the photosensitive member 5. In this case, medium-quality high-quality paper as the belt 70 is stretched around the drum circumference ¼ of the photosensitive member 5 so that the paper sheet is in the longitudinal direction, and a load of 0.98 N (100 g), for example, is applied to one side of the belt 70. 71, a force gauge 72 is installed on the other side, the force gauge 72 is pulled, the load at the time when the belt 70 moves is read, and a friction coefficient μs = 2 / π × ln (F / 0.98) (however, , Μ: coefficient of static friction, F: measured value).

FIG. 12 shows the rotation time of the photoconductor 5 and the friction coefficient (3 of the photoconductor 5 when the new photoconductor 5 is rotated independently under the following conditions and the electrophotographic lubricant is applied by the brush roller 17a. The relationship of the location) was shown.
Condition Photoconductor Diameter 30Φ
Photoconductor linear velocity 125mm / s
Lubricant molding Material Zinc stearate
Spring pressure 1000mN
Brush roller material Conductive nylon
Density 30K F / inch ²
Thickness 10D
Biting into the photoreceptor 1.0mm
According to FIG. 12, by setting the coating time to 100 s or longer, the friction coefficient of the photosensitive member 5 can be lowered and saturated (0.2 or lower).

FIG. 4 is an enlarged cross-sectional view of a main part in the vicinity of a contact portion between a cleaning blade and a photosensitive member when an electrophotographic lubricant is applied. It is a principal part expanded sectional view same as the above when not apply | coating the lubricant for electrophotography. 1 is an overall configuration diagram of a full-color small printer. FIG. It is the schematic which shows the structure of a process cartridge. It is a flowchart which shows operation | movement of a latent image carrier new article detection means. 4A and 4B are schematic diagrams schematically illustrating the shape of a toner. FIG. 4A is a diagram for explaining a shape factor SF-1, and FIG. 4B is a diagram for explaining a shape factor SF-2. 2A and 2B are schematic diagrams illustrating an outer shape of a toner, where FIG. 3A is a diagram illustrating the appearance of the toner, and FIG. FIG. 3 is a schematic configuration diagram of toner. It is the figure which showed the relationship between the particle size of the additive added in the lubrication agent molded object 17b, and charging roller dirt. FIG. 6 is a diagram showing changes in the photoreceptor friction coefficient due to lubricant application during actual paper passing. It is a figure for demonstrating the measuring method of the friction coefficient of a photoreceptor. FIG. 6 is a diagram showing changes in lubricant application time and photoconductor friction coefficient over time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2A, 2B, 2C, 2D Process cartridge 3 Transfer apparatus 3a Transfer belt 5 Photosensitive body (latent image carrier)
6 Writing unit 7 Duplex unit 8 Reversing unit 9 Fixing device 10A, 10B, 10C, 10D Developing device 11, 12 Paper feed cassette 13 Manual feed tray 14 Charging means 14a Charging roller 14b Charging roller cleaning brush 15 Cleaning means 15a Cleaning blade 15d Toner transport Auger 17 Lubricant coating device 17a Brush roller 17b Lubricant molded body 17c Brush roller scraper 17d Pressure spring 20 Reverse paper discharge path 25 Paper discharge roller pair 26 Paper discharge trays 45a, 45b Transport guide plates 46, 60 Transport rollers 55, 56 Separation Paper Feed Unit 58 Paper Adsorption Roller 59 Registration Roller Pair P Transfer Paper

Claims (17)

In the electrophotographic lubricant applied to the latent image carrier to which toner having a circularity of 0.94 or more is supplied,
2Y / 1000 ≦ X ≦ Y / 10
Y: Toner particle size (μm)
X: Particle size of inorganic additive (μm)
An inorganic additive having the following relationship is added: a lubricant for electrophotography. 2. The electrophotographic lubricant according to claim 1, wherein the inorganic additive is one or more substances selected from the group consisting of silica, titania, alumina, magnesia, zirconia, ferrite and magnetite. 3. The electrophotographic lubricant according to claim 1, wherein the main component of the electrophotographic lubricant is a fatty acid metal salt or fluorine fine particles. The lubricant for electrophotography according to claim 3, wherein the addition amount of the inorganic additive is 1 to 30 wt% with respect to the main component. A lubricant application device for applying the electrophotographic lubricant according to any one of claims 1 to 4 to a latent image carrier,
The lubricant application device includes a brush-like roller that rotates about a rotation axis and abuts on the latent image carrier, and the electrophotographic lubricant is a lubricant molded body molded in a solid state. And the brush-like roller is configured to apply the electrophotographic lubricant to the latent image carrier by rubbing and scraping the lubricant molded body. Lubricant application device. A latent image carrier new article detecting means for detecting the first use of the latent image carrier is further provided, and when the first use of the latent image carrier is detected, the electrophotographic lubricant is applied to the latent image carrier. The lubricant application device according to claim 5, wherein the lubricant application device is configured to be applied. The lubricant application device according to claim 6, wherein the latent image carrier after the electrophotographic lubricant is applied has a friction coefficient of 0.4 or less. The lubricant application device according to any one of claims 5 to 7, further comprising pressing means for pressing the lubricant molded body against the brush-like roller with a pressure of 200 mN or more. The brush-like roller is rotated in a rotating direction of the rotating latent image carrier, and a ratio of peripheral speeds of the brush-like roller and the latent image carrier is 0.8 to 1.2. The lubricant application device according to any one of claims 5 to 8. A charging means for charging the latent image carrier by bringing the charging member into contact with or in proximity to the charging member, a developing means for developing the toner by attaching toner to the latent image of the latent image carrier, and a toner remaining on the latent image carrier by a cleaning blade A process cartridge comprising at least one cleaning means for cleaning, a latent image carrier, and the lubricant application device according to any one of claims 5 to 9. An image forming apparatus comprising the process cartridge according to claim 10. An image forming apparatus comprising the lubricant application device according to claim 5. The toner has a volume average particle diameter of 3 to 8 μm and a ratio Dv / Dn of the volume average particle diameter Dv to the number average particle diameter Dn is in a range of 1.00 to 1.40. The image forming apparatus according to 11 or 12. The image according to any one of claims 11 to 13, wherein the toner has a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. Forming equipment. The image forming apparatus according to claim 11, wherein the toner has a substantially spherical shape. The shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and the ratio r2 / r1 between the major axis r1 and the minor axis r2 is 0.00. The ratio r3 / r2 between the thickness r3 and the minor axis r2 is in the range of 0.7 to 1.0, in the range of 5 to 1.0. The image forming apparatus described in 1. In the toner, a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent is crosslinked and / or extended in an aqueous medium. The image forming apparatus according to claim 11, wherein the image forming apparatus is obtained.