JP5101797B2 - Process cartridge having lubricant application means and image forming apparatus - Google Patents

Description

The present invention is a copying machine, a facsimile, in which relates to a process cartridge and an image forming equipment comprising a lubricant applying means for applying a lubricant to the image bearing member in the electrostatic copying process such as a printer.

  In an image forming apparatus using an electrostatic copying process, there is a demand for higher image quality of printed images. In this trend of improving the image quality, as the improvement on the toner side for visualizing the latent image, higher circularity and smaller particle size are being promoted in order to form a high-definition image. Specifically, since the pulverized toner manufactured by the pulverization method has a limit to these characteristics, it is possible to use a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method that can easily increase the circularity and reduce the particle size. An increasing number of products use polymerized toner produced.

  However, high-circular toner is known to have poor cleaning properties. Conventionally, as a cleaning means in the case of using pulverized toner, a cleaning means that scrapes the cleaning blade from the surface of the photosensitive member at the edge of the cleaning blade by rubbing the cleaning blade on the surface of the photosensitive member as a toner image carrier is used. ing. The highly rounded toner rolls without being caught by the edge of the cleaning blade and easily passes through the cleaning blade, so that the cleaning property is considered to be poor. In order to clean such highly rounded toner well, a lubricant is applied to the surface of the photosensitive member, the friction coefficient of the photosensitive member is lowered, and the friction between the photosensitive member and the toner is reduced to reduce the toner from the photosensitive member. There are known methods for making it easier to scrape off.

  Also, due to the pressure applied by the cleaning blade that is rubbed against the surface of the photoconductor, discharge products such as toner, toner external additives, and NOx adhere to the photoconductor over time. An image may occur. In order to prevent this, it is necessary to sufficiently reduce the friction coefficient of the photoconductor, and it is effective to apply a lubricant to the photoconductor.

  In addition, there are a corona method and a contact or proximity charging method as a method for charging the photoconductor, but recently, due to the environment, a method using a contact or proximity charging method in which ozone is relatively difficult to generate is increasing. In the contact or proximity charging method, a DC voltage on which an AC voltage is superimposed is applied in order to improve charging uniformity. However, if the AC voltage is superimposed, the surface of the photoreceptor is roughened. For this reason, the friction coefficient of the photosensitive member tends to increase, and the above problem becomes remarkable. Therefore, in a device using a charging device on which an alternating voltage is superimposed, it is more important to apply a lubricant in order to lower the coefficient of friction of the photoreceptor.

  As a device for applying the lubricant to the photoconductor, a solid lubricant obtained by solidifying a lubricant such as zinc stearate, and a brush roll rotating in one direction while simultaneously contacting the solid lubricant and the photoconductor are provided. A provided lubricant application device is known.

As an example of the lubricant application device, in Patent Document 1, the brush roll as the lubricant application device has a density of 20000 to 60000 pieces / (inch) ² of 7.5 to 15 denier brush fibers on the peripheral surface of the rotation support shaft. And the solid lubricant has a pencil hardness of H, F, HB or B and is in contact with the brush roll at a pressure of 1.18 N / m or less. Things have been proposed. An object of this lubricant application apparatus is to maintain the application of solid lubricant over a long period of time by suppressing the consumption (scraping amount) of the fixed lubricant as much as possible with a simple mechanism.

JP 2003-57996 A

  As described above, by applying a lubricant to the surface of the photoconductor to lower the coefficient of friction of the photoconductor, it is possible to maintain good cleaning performance and greatly reduce filming. However, if the amount of lubricant applied is excessive, problems such as abnormal image generation and shortening of the service life of the apparatus occur. Further, if the solid lubricant is too hard, a large force is required for the brush roller to scrape the solid lubricant. Therefore, although the force for pressing the solid lubricant against the brush roller is increased, the solid lubricant is liable to break and the brush to fall down, so that an appropriate amount of lubricant is not applied and an abnormal image may occur. In addition, when a simple compression spring is used as the pressing means, the spring constant increases, and a difference in applied pressure is produced between the initial time and the elapsed time, so that the lubricant application amount changes with time. On the other hand, if the solid lubricant is too soft, chipping and cracking are likely to occur during manufacturing, secondary processing, transport, and assembly even when the machine is not operating. Also, the amount of lubricant applied tends to be excessive.

The present invention has been made in view of the above-mentioned background, and an object of the present invention is to provide a process including a lubricant application unit capable of stably applying an appropriate amount of lubricant to an image carrier over a long period of time. A cartridge and an image forming apparatus are provided.

In order to achieve the above object, the invention of claim 1 is directed to an image carrier that carries a toner image, a lubricant application unit that applies a lubricant to the image carrier, and a cleaning that cleans the surface of the image carrier. In the process cartridge detachably attached to the image forming apparatus in which a charging roller disposed in close proximity to and maintaining a minute gap is maintained between the image forming apparatus and the surface of the image carrier, the lubricant applying unit includes: A solid lubricant made into a solid lubricant, a roller-like brush that rubs and scrapes the solid lubricant while rotating, and applies the image to the image carrier, and a pressure that presses the solid lubricant against the brush A brush fiber of 5 to 15 denier is provided on the peripheral surface of the rotary support shaft at a density of 20000 to 100,000 per square inch, and the solid lubricant is added to the brush. A force for pressing the 2~12N / m, the measurement test force hardness of said solid lubricant 50 mN, when the load duration of 30 seconds, when the load is to was set to measure the test force is increased 30 seconds 0mN The Martens hardness is 40 to 70 N / mm ² .
According to a second aspect of the present invention, in the process cartridge of the first aspect, the material of the brush is polyester.
According to a third aspect of the invention, in the process cartridge of the first or second aspect, the brush is insulative.
According to a fourth aspect of the present invention, in the process cartridge according to the first, second, or third aspect, a peripheral speed ratio of the brush to the image carrier is in a range of 0.8 to 1.2. It is.
According to a fifth aspect of the present invention, there is provided an image carrier that carries a latent image, a charging roller that is disposed in close proximity to the surface of the image carrier while maintaining a minute gap, and an electrostatic An exposure device that forms a latent image, a developing device that converts the electrostatic latent image formed on the image carrier into a toner image, a transfer device that transfers the toner image to a transfer target, and an image on the image carrier In an image forming apparatus including a cleaning device that cleans residual transfer residual toner and a lubricant application unit that applies a lubricant to the surface of the image carrier, the lubricant application unit solidifies the lubricant. A solid lubricant, a roller-like brush that rubs and scrapes the solid lubricant while rotating and applies the image to the image carrier, and pressing means that presses the solid lubricant against the brush. ~ 15 denier brush fiber on the circumference of the rotating support shaft Provided with a density of 20000 to 100,000 per inch, the force for pressing the solid lubricant against the brush is 2 to 12 N / m, the hardness of the solid lubricant is a measurement test force of 50 mN, and the required load time At 30 seconds, the load is 40 to 70 N / mm ² in terms of Martens hardness when the measurement test force is increased from 0 mN for 30 seconds .
According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, the toner used in the developing device has an average circularity of 0.93 or more.
Further, in the image forming apparatus of claim 5 or 6, the toner used in the developing device has a volume average particle size of 3 to 8 μm, and a volume average particle size (Dv) and a number average particle size. The ratio (Dv / Dn) to (Dn) is in the range of 1.00 to 1.40.
According to an eighth aspect of the present invention, in the image forming apparatus of the fifth, sixth or seventh aspect, the toner used in the developing device 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. It is characterized by being in the range of 180.
According to a ninth aspect of the present invention, in the image forming apparatus according to the fifth, sixth, seventh, or eighth aspect, the toner used in the developing device has a ratio of the major axis to the minor axis (r2 / r1) of 0.5. The ratio of thickness to minor axis (r3 / r2) is in the range of 0.7 to 1.0 in the range of -1.0, and the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 is satisfied. It is characterized by this.
The invention according to claim 10 is the image forming apparatus according to claim 5, 6, 7, 8 or 9, wherein the toner used in the developing device is a polyester prepolymer having a functional group containing a nitrogen atom, polyester, or coloring. The toner composition is characterized in that the toner composition containing an agent and a release material is crosslinked and / or extended in the presence of resin fine particles in an aqueous medium.

In these lubricant application devices, process cartridges, and image forming apparatuses, the hardness of the solid lubricant and the force for pressing the solid lubricant are defined, and an appropriate amount of lubricant is stably supplied over a long period of time. Apply to. The Martens hardness of the solid lubricant is measured at a test force of 50 mN and a load time of 30 seconds. As shown in an experiment described later, when a solid lubricant having a Martens hardness greater than 70 N / mm ² is used, the force for pressing the solid lubricant necessary for cutting increases, and the solid lubricant Cracks, brush fall, and filming problems over time. In addition, when a simple compression spring is used as the pressing means, the spring constant increases, and a difference in the applied pressure between the initial time and the elapsed time results in insufficient application of the lubricant over time. There was no condition that could solve all of these problems even when the pressing force was changed. When a solid lubricant having a Martens hardness of 40 to 70 N / mm ² is used and the pressing force is 2 to 12 N / m, the solid lubricant cracks, the brush falls, There was no occurrence and the lubricant could be applied stably. At other pressures, an abnormal image was generated due to filming, cracking or chipping of the solid lubricant, and brush falling. In addition, when a solid lubricant having a Martens hardness of less than 40 N / mm ² is used, chipping and cracking are likely to occur during manufacturing, secondary processing, transportation, and assembly even when the machine is not operating. In addition, it is too soft and is excessively applied to the image carrier, thereby generating an abnormal image and adversely affecting other devices in contact with the image carrier. From these facts, the Martens hardness of the solid lubricant is 40 to 70 N / mm ^{2 and} the force for pressing the solid lubricant against the brush is 2 to 12 N / m. An appropriate amount of lubricant can be applied to the image carrier.

    According to the first to tenth aspects of the present invention, there is an excellent effect that an appropriate amount of lubricant can be applied to the image carrier stably over a long period of time.

  Hereinafter, an embodiment in which the present invention is applied to a full-color laser printer (hereinafter referred to as a printer) which is an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram showing the internal configuration of the printer. In the printer main body 1, four photoreceptor units 2A, 2B, 2C, and 2D are detachably attached to the apparatus main body 1, respectively. Each of the photoreceptor units 2A, 2B, 2C, and 2D includes a drum-like photoreceptor 5 as an image carrier. In addition, developing devices 10A, 10B, 10C, and 10D having different toner colors are arranged in correspondence with the photoreceptor units 2A, 2B, 2C, and 2D, respectively. Here, the photoconductor units 2A, 2B, 2C, and 2D are units having the same configuration, the photoconductor unit 2A forms an image corresponding to magenta, and the photoconductor unit 2B is an image corresponding to cyan. The photoreceptor unit 2C forms an image corresponding to the yellow color, and the photoreceptor unit 2D forms an image corresponding to the black color. Each of the photoreceptor units 2A, 2B, 2C, and 2D includes a charging roller 14 as a charging device, a brush roller and a cleaning blade as a cleaning device, around the photoreceptor 5. The photoreceptor units 2A, 2B, 2C, and 2D will be described in detail later.

  The developing devices 10A, 10B, 10C, and 10D have the same configuration, and are different only in the color of the toner to be used. Accordingly, the subscripts A, B, C, and D will be omitted below, and the developing device 10 will be described. The developing device 10 is a two-component developing device using a developer composed of toner and carrier. The developing device 10 includes a developer accommodating portion that accommodates the developer, a developing roller as a developer carrying member disposed so as to face and face the surface of the photosensitive member 5, a screw that conveys and agitates the developer, and toner A density sensor. The developing roller is composed of an outer rotatable sleeve and an inner magnet. Further, the toner is supplied from the toner supply device according to the output of the toner density sensor. The developing roller is configured to carry the developer and transport it to a position facing the photoconductor 5 and to develop the toner by supplying toner to the electrostatic latent image on the photoconductor 5.

  At the center of the printer main body 1, a transfer unit including a transfer belt 3 that is wound around a plurality of support rollers and is rotatable in the direction of arrow A is disposed. The transfer belt 3 is disposed so as to rotate in contact with and opposed to the photoreceptors 5 of the photoreceptor units 2A, 2B, 2C, and 2D. A transfer brush 57 is provided inside the transfer belt 3 corresponding to each photoconductor 5. Further, a paper suction roller 58 for charging the transfer paper P to a predetermined polarity is provided near the entrance of the transfer paper P of the transfer belt 3. As the transfer belt 3, a resin material such as polyvinylidene fluoride, polyimide, polycarbonate, or polyethylene terephthalate is molded into a seamless belt and used. These materials can be used as they are, or the resistance can be adjusted with a conductive material such as carbon black. Further, using these resins as a base layer, a surface layer may be formed by a method such as spraying or dipping to form a laminated structure.

  A writing unit 6 is disposed above the photoreceptor units 2A, 2B, 2C, and 2D. The writing unit 6 is arranged in four laser diode (LD) type light sources prepared for each color, a set of polygon scanners composed of a six-sided polygon mirror and a polygon motor, and an optical path of each light source. It is composed of a lens such as an fθ lens, a long WTL, or a mirror. The laser light emitted from the laser diode is deflected and scanned by a polygon scanner and irradiated onto each photoconductor 5.

  A duplex unit 7 is disposed below the transfer belt 3. The duplex unit 7 includes a pair of conveyance guide plates 45 a and 45 b and a plurality of paired conveyance rollers 46. In the double-sided image forming mode in which images are formed on both sides of the transfer paper, the transfer paper P, which is formed on one side and conveyed to the reverse conveyance path 54 of the reversing unit and transferred switchback, is received and fed to the paper feeding unit. Transport toward

  On the left side of the apparatus main body, a reversing unit 8 that reverses and discharges the transfer paper P after image formation or transports it to the duplex unit 7 is mounted. The reversing unit 8 includes a plurality of paired transport rollers and a plurality of paired transport guide plates. Then, the transfer paper P used to form a double-sided image is turned upside down and carried out to the double-sided unit, the transfer paper P after image formation is discharged out of the machine in the same orientation, or the front and back are turned upside down. It works to discharge. The paper feed unit provided with the paper feed cassette is provided with separate paper feed units 55 and 56 for separating and feeding the transfer paper P one by one.

  Further, a fixing device 9 is provided between the transfer belt 3 and the reversing unit 8 to fix the image on the transfer paper 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. Yes.

  Further, in the lower part of the apparatus main body, paper feed cassettes 11 and 12 that can store transfer papers P of different sizes are arranged in two upper and lower stages. Further, a manual feed tray 13 is provided on the right side surface of the apparatus main body so as to be openable and closable in the direction indicated by the arrow B, and the manual feed tray is opened so that manual feeding can be performed therefrom.

  Next, the operation of the printer will be described. First, the operation of this printer during full color image formation will be described. When the printer receives full-color image data, the photoreceptors 5 of the photoreceptor units 2A, 2B, 2C, and 2D rotate in the clockwise direction in FIG. Then, the surface of each photoconductor 5 is uniformly charged by the charging roller 14. Next, laser light corresponding to each color image is irradiated to each photoconductor 5 of the photoconductor units 2A, 2B, 2C, and 2D by the writing unit, and a latent image corresponding to the image data of each color is formed. When each latent image reaches the position of each developing device 10 by the rotation of each photosensitive member 5, the latent image is developed with each toner to form a toner image of each color.

  On the other hand, since the paper P is fed from the paper feed cassettes 11 and 12 or the manual feed tray 13, the transfer paper P is conveyed and sent to a temporary stop position of the registration roller pair 59 provided immediately before the transfer belt 6. The registration roller pair 59 sends the transfer paper P toward the transfer belt 3 at a timing that coincides with the toner image formed on each photoconductor 5. The transferred transfer paper P is charged with a positive polarity by a paper suction roller 58 disposed in the vicinity of the entrance of the transfer belt 3 and is electrostatically attracted to the surface of the transfer belt 3. Then, while the transfer paper P is conveyed while adsorbed to the transfer belt 3, magenta, cyan, yellow, and black toner images are sequentially transferred to form a four-color superimposed full-color toner image. The

  The transfer paper P is melted and fixed by applying heat and pressure by the fixing device 9. Thereafter, the paper is reversed and discharged to the paper discharge tray 26 at the upper part of the apparatus main body through the paper discharge system corresponding to the designated mode, or straightly discharged from the fixing device 9 through the reversing unit 8. To do. When the double-sided image forming mode is selected, the toner image forming unit is fed back to the double-sided unit 7 after being sent to the reverse carrying path in the reversing unit 8 and then fed back to the double-sided unit 7. Thus, the image is discharged after the image is formed on the back surface. Thereafter, when two or more image formations are instructed, the above-described image forming process is repeated. On the other hand, the surface of each photoconductor 5 after the transfer of the toner image is cleaned by a brush roller and a cleaning blade to prepare for the formation of the next electrostatic latent image.

  Next, the operation of the image forming apparatus when forming a monochrome image will be described. When the image forming apparatus receives black and white image data, the driven roller supporting the transfer belt 3 is moved downward so as to face the paper suction roller 58, and the transfer belt 3 is a photoconductor for magenta, cyan, and yellow. 5 apart. The black photoconductor 5 rotates clockwise in FIG. 1, and the surface of the black photoconductor 5 is uniformly charged by the charging roller 14. Further, a laser beam corresponding to a black image is irradiated on the photoconductor 5 of the photoconductor unit 2D for black to form a latent image. When the latent image reaches the position of the developing device 10 for black, the latent image is developed with black toner to become a toner image. At this time, the image forming units for the three colors other than black are stopped, and unnecessary wear is prevented.

  On the other hand, the transfer paper P is fed from the paper feed cassettes 11 and 12 or the manual feed tray 13 and sent to a temporary stop position of a registration roller pair 59 provided immediately before the transfer belt 6. The registration roller pair 59 sends the transfer paper P toward the transfer belt 3 at a timing that coincides with the toner image formed on the black photoreceptor 5. The transferred transfer paper P is charged with a positive polarity by a paper suction roller 58 disposed in the vicinity of the entrance of the transfer belt 3 and is electrostatically attracted to the surface of the transfer belt 3. Since the transfer paper P is conveyed while adsorbed to the transfer belt, even if the transfer belt is separated from the magenta, cyan, and yellow photoconductors 5, the transfer paper P is conveyed to the black photoconductor 5, The toner image is transferred. In order to stably transfer and transfer the transfer paper P, the transfer belt 3 needs to be made of a material having at least a surface layer having a high resistance. The transfer paper P is fixed by the fixing device as in the case of a full-color image, and processed through a paper discharge system corresponding to a designated mode. Thereafter, when two or more image formations are instructed, the above-described image forming process is repeated.

  Next, the photoreceptor units 2A, 2B, 2C, and 2D will be described in detail. The photoreceptor units 2A, 2B, 2C, and 2D perform the same configuration and operation. Accordingly, the subscripts A, B, C, and D are omitted below, and the photoconductor unit 2 will be described. FIG. 2 is a schematic configuration diagram of the photoconductor unit 2. The photoconductor unit 2 is provided with a positioning main reference portion 51 as a reference for attaching / detaching it to the apparatus main body, and the front side positioning sub reference portion 52 and the rear side positioning sub reference portion 53 are connected to the bracket 50. These are provided integrally with each other, and when the photosensitive unit 2 is mounted on the apparatus main body 1, the reference unit makes it possible to reliably position the photosensitive unit 2 at a predetermined mounting position. As described above, the photoconductor unit 2 includes the charging roller 14, the brush roller 15, and the cleaning blade 47 around the photoconductor 5. In this embodiment, the photosensitive member 5 has a diameter of 30 mm, and each photosensitive member is driven to rotate in the direction of arrow C at 162 mm / sec.

The charging roller 14 is in pressure contact with the surface of the photoconductor 5 via a gap management member 17 and is disposed so as to be close to and opposed to the photoconductor 5 while maintaining a minute gap G (gap). The charging roller 14 is formed by providing a material having a volume resistance of 10 ⁴ to 10 ⁹ Ω · cm on a cored bar made of a metal such as stainless steel having a diameter of about 6 to 10 mm. If the mandrel is thinner than 6 mm, the influence of the deflection when the charging member is cut or when the photosensitive member is pressed cannot be ignored, and the required gap accuracy is difficult to obtain. On the other hand, if the cored bar is too thick than 10 mm, the charging roller 14 becomes large or the mass becomes heavy. On the other hand, if the volume resistance of the charging roller 14 is lower than 10 ⁴ Ω · cm, leakage of the charging bias tends to occur when the photoreceptor 5 has a defect such as a pinhole. On the other hand, if the volume resistance is too high at 10 ⁹ Ω · cm, sufficient discharge is not generated and a uniform charged potential cannot be obtained. A power source (not shown) is connected to the charging roller 14 and a predetermined voltage is applied. The applied voltage is preferably a voltage obtained by superimposing an AC voltage on a DC voltage, and the surface of the photoreceptor 5 can be more uniformly charged. In addition, a charging cleaning roller 49 is provided above the charging roller 14 as a cleaning member for cleaning the surface of the charging roller 14. The electrifying cleaning roller 49 is formed by bonding a roller made of an insulating sponge material called melamine foam to a core metal having a diameter of 5 mm. The charging cleaning roller 49 is in free contact with the charging roller 17 only by its own weight, and cleans the surface of the charging roller 17 while rotating in the follower direction as the charging roller 17 rotates.

  The brush roller 15 and the cleaning blade 47 are disposed in contact with the photosensitive member 5. Further, a flicker device 19 for blowing off the toner attached to the brush roller 15 and a toner transport auger 48 for transporting the waste toner removed from the photoreceptor 1 to a waste toner storage unit (not shown) are provided. The brush roller 15 is provided with 5 to 15 denier brush fibers at a density of 20000 to 100,000 per square inch on the peripheral surface of the rotation support shaft.

  Further, in the photoreceptor unit 2, a solid lubricant 16 applied to the surface of the photoreceptor 5 in order to reduce the friction coefficient on the surface of the photoreceptor 5, and a pressurizing unit for pressing the solid lubricant 16 against the brush roller 15. A compression spring 60 is provided. As the brush roller 15 rotates, the solid lubricant 16 is rubbed and scraped to adhere to the brush fibers of the brush roller 15 as a shaving powder. Then, it is conveyed to a contact portion with the photoconductor 5 and the adhering powdery lubricant is applied to the surface of the photoconductor 5.

  Examples of the solid lubricant 16 include lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate and zinc linolenate. Fatty acid metal salts, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-oxafluoropropylene copolymer Fluorine-based resins such as In particular, a metal stearate having a large effect of reducing the friction of the photoreceptor 5 and further zinc stearate are more preferable.

  As described above, the brush roller 15 collects the transfer residual toner on the photoconductor 5 while rotating, and also has a function as a lubricant application means for applying the solid lubricant 16 to the surface of the photoconductor 1. By applying the solid lubricant 16, the coefficient of friction on the surface of the photoreceptor 5 is lowered, and finally the remaining toner is scraped off and removed by the cleaning blade 47. Therefore, the cleaning can be performed efficiently without damaging the surface of the photoreceptor 5. Further, the brush roller 15 is scraped off from the photosensitive member 5 by the cleaning blade 47 while rotating, holds the toner accumulated in the portion E in the figure, and blows off the toner by the flicker device 19 and moves to the toner conveying auger 48 side. The toner transport auger 48 rotates to transport the collected waste toner to the waste toner storage unit 18 shown in FIG.

Here, the solid lubricant 16 has a Martens hardness of 40 to 70 N / mm ² . The test force at the time of the hardness measurement was a measurement test force of 50 mN and a load required time of 30 seconds, and the load was increased from 0 mN to 30 seconds so that the test force was obtained. The measurement environment is 23 ° C. and 50%. Moreover, the force which presses the solid lubricant 16 was 2-12 N / m. When the solid lubricant 16 having a Martens hardness of greater than 70 N / mm ² is used, the pressure applied to the solid lubricant 16 necessary for cutting increases, causing problems such as cracking of the solid lubricant 16 and brush fall of the brush. To do. In addition, the spring constant of the compression spring 60 for pressurization also increases, and a difference in applied pressure between the initial time and the lapse of time results in insufficient application of the lubricant over time. Further, when a weight is used as a pressurizing means for pressing the solid lubricant 16 against the brush roller 15, there is a demerit that a space is increased. Further, when the solid lubricant 16 having a Martens hardness of less than 40 N / mm ² is used, chipping and cracking are likely to occur at the time of manufacturing, secondary processing, transport, and assembly even when the machine is not operating. In addition, it is too soft and is applied too much to the photoreceptor 5, so that the charging roller 14 is soiled and the life of the charging roller 14 and the charging cleaning roller 49 is shortened. For these reasons, the solid lubricant 16 having a Martens hardness of 40 to 70 N / mm ² is used.

  The brush material of the brush roller 15 is polyester fiber. The polyester fiber is less likely to fall down and can be stably applied to the photoreceptor 5 by shaving the solid lubricant 16 stably over time. Further, the brush is made of an insulating material. Thereby, the cost can be reduced and the cleaning property can be improved.

  The brush roller 15 is rotated in the same direction at a portion in contact with the photoreceptor 5. By rotating in this direction, the lubricant adhering to the brush roller 15 can be supplied without giving an impact to the photoreceptor 5. Further, the peripheral speed ratio between the brush roller 15 and the photosensitive member 5 (photosensitive member peripheral speed / brush roller peripheral speed) 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 lubricant is decreased, and defective cleaning or filming occurs. On the other hand, if it exceeds 1.2, the photoreceptor 5 may be damaged by an impact, and the life of the photoreceptor 5 may be shortened. Further, in order to supply a sufficient amount of lubricant from the brush roller 15 to the photosensitive member with a small impact, it is more preferably in the range of 1.0 to 1.1. In particular, in the case of using the charging roller 14 on which the AC voltage is superimposed as in the printer of this embodiment, it is necessary to apply a large amount of lubricant to reduce the friction coefficient of the photoconductor 5. Here, the lubricant application apparatus proposed in Patent Document 1 has a small amount of lubricant applied, and cannot sufficiently reduce the frictional resistance of the photosensitive member 5, thereby reducing good cleaning performance and filming. The effect to do was not obtained. In the printer of this embodiment, the frictional resistance of the photoconductor 5 is achieved by setting the peripheral speed ratio of the brush roller 15 and the photoconductor 5 (photoconductor peripheral speed / brush roller peripheral speed) to 0.8 to 1.2. An appropriate amount of lubricant can be applied to sufficiently reduce the temperature, and good cleaning performance and filming can be reduced.

FIG. 3 shows the results obtained by running. The vertical axis represents the failure rank, and the horizontal axis represents the pressure applied to the solid lubricant 16. When the solid lubricant 16 had a Martens hardness of less than 40 N / mm ² , the solid lubricant 16 was cracked or chipped, and there was no applied pressure that did not cause an abnormal image. Even when the Martens hardness was greater than 70 N / mm ² , there was no pressurizing force at which filming occurred or the brush roller 15 fell and no abnormal image was generated. Films with a Martens hardness of 40 to 70 N / mm ² did not generate filming after 600,000 sheets with a pressure of ² to 12 N / m. At other pressures, filming, cracking or chipping of the solid lubricant 16, abnormal images due to the falling of the brush roller 15, etc. occurred. Considering the life of the solid lubricant 16 and the charging cleaning roller 49 of the charging roller 17, the applied pressure is more preferably 2 to 8 N / m.

  Next, the photoconductor 5 will be described in detail. The photoreceptor 5 is formed by laminating an undercoat layer, a charge generation layer mainly composed of a charge generation material, and a charge transport layer mainly composed of a charge transport material on a conductive support.

As the conductive support, one having a volume resistance of 10 ⁴ Ω · cm or less, for example, a metal tube such as aluminum or stainless steel, or a metal such as nickel processed into an endless belt shape is used.

  The undercoat layer generally contains a resin as a main component, but these resins are resins having high resistance to dissolution in general organic solvents in consideration of applying a photosensitive layer thereon with a solvent. It is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, alcohol-soluble resins such as copolymer nylon, and curable resins that form a three-dimensional network structure such as polyurethane, alkyd-melamine, and epoxy. Further, a fine powder of metal oxide such as titanium oxide, silica, or alumina may be added to the undercoat layer in order to prevent moire and reduce residual potential. This undercoat layer can be formed using an appropriate solvent and coating method. The thickness of the undercoat layer is suitably from 0 to 5 μm.

  The charge generation layer is a layer mainly composed of a charge generation material, and representative examples include a monoazo pigment, a disazo pigment, a trisazo pigment, and a phthalocyanine pigment. These charge generation materials can be formed by dispersing together with a binder resin such as polycarbonate using a solvent such as tetrahydrofuran or cyclohexanone and applying a dispersion. Application is performed by dip coating, spray coating, or the like. The thickness of the charge generation layer is usually 0.01 to 5 μm.

  The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent such as tetrahydrofuran, toluene, dichloroethane, and applying and drying the solution. Among charge transport materials, low molecular charge transport materials include electron transport materials and hole transport materials. Examples of the electron transport material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 1, Examples include electron-accepting substances such as 3,7-trinitrodibenzothiophene-5,5-dioxide. Examples of hole transport materials include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, thiophene derivatives, etc. These electron donating substances are listed. The binder resin used in the charge transport layer together with the charge transport material is thermoplastic such as polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyester, polyarylate, polycarbonate, acrylic, epoxy, melamine, phenol, etc. Or a thermosetting resin is mentioned. The thickness of the charge transport layer may be appropriately selected in the range of 5 to 30 μm according to desired photoreceptor characteristics.

  Further, a protective layer can be formed on the surface of the photoreceptor for the purpose of protecting the photosensitive layer and improving durability. As a constitution of the protective layer, mechanical durability can be improved by dispersing a filler in a binder resin. The amount of the filler added to the protective layer is 10 to 70 parts by weight, preferably 20 to 50 parts by weight with respect to 100 parts by weight of the binder resin. When the amount of the filler is less than 10 parts by weight, the wear is large and the durability is inferior. As the filler added to the protective layer, fine powders of metal oxides such as titanium oxide, silica, and alumina can be used. When the particle size of the filler is too large, the exposure light is scattered by the protective layer, so that the resolution is lowered and the image quality is inferior. Moreover, when the particle size of a filler is too small, it is inferior to abrasion resistance. Therefore, the particle size of the filler added to the protective layer is suitably 0.1 to 0.8 μm. The protective layer can be formed by dispersing filler and binder resin using a suitable solvent and applying the dispersion by spray coating. The binder resin used for the protective layer, the solvent can be the same material as the charge transport layer, and as the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, polyester, polyarylate, There are thermoplastic or thermosetting resins such as polycarbonate, acrylic, epoxy, melamine, and phenol, and tetrahydrofuran, toluene, dichloroethane, and the like can be used as the solvent. The thickness of the protective layer is preferably 3 to 10 μm in order to improve the durability and not impair the electrostatic characteristics of the photosensitive layer. Furthermore, a charge transport material, an antioxidant, or the like can be added to the protective layer.

  In the printer of this embodiment, as described above, the photosensitive member 5, the charging device, the cleaning device, and the lubricant application unit are integrally supported, and the process cartridge is formed detachably on the image forming apparatus main body. Yes. In addition to this, the process cartridge may include the developing device 10. This process cartridge can improve the cleaning on the photoconductor 5 and cause deterioration in image quality even in an image forming process in which the degree of circularity is high and development using toner having a small particle diameter is performed. There can be no process cartridge. Further, since the cleaning function can be maintained by stably applying the lubricant to the photoconductor 5 over a long period of time, the life of the process cartridge is also improved.

  Next, the toner suitably used for the printer of this embodiment will be described. The toner preferably has an average circularity of 0.93 to 1.00. The degree of circularity SR = (peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image). The closer the toner is to a true sphere, the closer the value is to 1.00. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated. When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small, so that the transferability is excellent. On the other hand, in a conventional apparatus, toner with a high degree of circularity is likely to enter the gap between the photosensitive member 5 and the cleaning blade 47 in the blade type cleaning. However, in the printer of this embodiment, the brush roller 15 satisfactorily applies the lubricant to the surface of the photoconductor 5, thereby reducing the friction coefficient of the surface of the photoconductor 5 and scraping the remaining toner with the cleaning blade 47. Cleaning can be performed.

  The volume average particle diameter of the toner is 3 to 8 μm, and the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is in the range of 1.00 to 1.40. Even when a toner having a small particle size and a narrow particle size distribution is used, good cleaning properties can be obtained. By narrowing the particle size distribution of the toner, the charge distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased. It is difficult to clean such a small particle size toner by overcoming the adhesion force with the photoreceptor 5 by the conventional blade type cleaning. If the particle size is small, the content of the external additive fine particles and the like of the toner tends to be relatively high, so that they are detached from the toner and filming is likely to occur on the photoreceptor 5. However, in the printer of the present embodiment, the brush roller 15 can satisfactorily apply the lubricant to the surface of the photoconductor 5, thereby reducing the friction coefficient of the surface of the photoconductor 5 and improving the cleaning performance of the cleaning blade 47. .

The toner shape factor SF-1 is preferably in the range of 100 to 180, and the shape factor SF-2 is preferably in the range of 100 to 180. The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). 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) Formula (1)
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 (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner onto the two-dimensional plane by the figure area AREA and multiplying by 100 / 4π.
SF-2 = {(PERI) 2 / AREA} × (100 / 4π) (2)
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.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

  When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photoconductor becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photoconductor The attraction force becomes weaker and the transfer rate becomes higher. On the other hand, spherical toner tends to cause poor cleaning in the blade type cleaning, but the brush roller 15 satisfactorily applies the lubricant to the surface of the photoconductor 5 by the lubricant application device of the present invention, so that the friction on the surface of the photoconductor 5 is achieved. Good cleaning can be performed by reducing the coefficient. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.

  Further, the shape of the toner used in this printer may be a substantially spherical shape. The shape of the toner can be expressed by the following shape rule. When a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present invention has a ratio of the major axis to the minor axis (r2). / R1) is preferably 0.5 to 1.0 and the ratio of thickness to minor axis (r3 / r2) is preferably in the range of 0.7 to 1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved. In addition, r1, r2, r3 can be measured by the following method, for example. That is, the toner is uniformly dispersed and adhered on a smooth measurement surface, and 100 particles of the toner are magnified 500 times by a color laser microscope “VK-8500” (manufactured by Keyence Corporation). The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values.

  In addition, as such a 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 in an aqueous solvent. And / or a toner obtained by an extension reaction. 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. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  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; phenol derivatives, oximes, polyisocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  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.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  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.

  The urea-modified polyester may contain a urethane bond together with 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. Usable solvents 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 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, 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 Carmine B, 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. The 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 and 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 to 2 μm, and particularly preferably 5 × 10 −3 to 0.5 μm. 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 stirring and mixing are performed using particles having an average particle size 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, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. . 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

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

(Toner production method)
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 usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

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 2000 parts by weight, preferably 100 to 1000 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 20000 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).

  Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salt, 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) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage 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 rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 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.

As described above, as described in the present embodiment, the solid lubricant 16 is rubbed with the brush roller 15 in which 5 to 15 denier brush fibers are provided at a density of 20000 to 100,000 per square inch on the peripheral surface of the rotation support shaft. In the apparatus for scraping and applying to the photoreceptor 5, the force for pressing the solid lubricant against the brush is 2 to 12 N / m, the hardness of the solid lubricant is measured at a test force of 50 mN, and the load time is 30 seconds. The Martens hardness is 40 to 70 N / mm ² . Under this condition, the solid lubricant is too hard, and the force to press against the brush becomes strong, causing cracks in the solid lubricant, falling down of the brush, and problems such as filming and insufficient application of lubricant over time. There is nothing. Further, since the solid lubricant is too soft, it does not cause problems such as chipping or cracking of the solid lubricant other than when the machine is operating, or generation of abnormal images due to excessive application of the photoconductor. Therefore, an appropriate amount of lubricant can be applied to the photoreceptor 5 stably over a long period of time.
Further, polyester is used as the material of the brush roller 15. Polyester is not prone to falling down, and the solid lubricant 16 can be shaved and applied to the photoreceptor 5 stably over time.
Further, the brush is made of an insulating material. Thereby, the cost can be reduced and the cleaning property can be improved.
The peripheral speed ratio between the brush roller 15 and the photosensitive member 5 (photosensitive member peripheral speed / brush roller peripheral speed) is in the range of 0.8 to 1.2. If the peripheral speed ratio is less than 0.8, the amount of lubricant supplied is reduced, and filming and cleaning failures occur. On the other hand, if it exceeds 1.2, the photoreceptor 5 may be damaged by an impact, and the life of the photoreceptor 5 may be shortened. In particular, in the case of using the charging roller 14 on which the AC voltage is superimposed as in the printer of the present embodiment, the surface of the photoconductor 5 is roughened, so it is necessary to increase the amount of lubricant applied to reduce the friction coefficient. is there. In this printer, by setting the peripheral speed ratio of the brush roller 15 and the photosensitive member 5 (photosensitive member peripheral speed / brush roller peripheral speed) to 0.8 to 1.2, the frictional resistance of the photosensitive member 5 is sufficiently increased. An appropriate amount of lubricant can be applied to lower the film, and good cleaning performance and filming can be reduced.
Further, the photoconductor 5, the solid lubricant 16, the lubricant application unit, and the brush roller 15 as a cleaning unit are at least integrally supported, and the photoconductor unit 2 is a process cartridge that can be attached to and detached from the printer main body 1. By using such a photoreceptor unit 2, an appropriate amount of lubricant can be stably applied to the photoreceptor 1 over a long period of time, and the life of the photoreceptor unit 2 can be extended.
Further, the lubricant applying means is used in a printer provided with the photosensitive member 1, the charging roller 14, the writing unit 6, the developing device 10, the transfer device, and the cleaning device. By using such a printer 1, an appropriate amount of lubricant can be applied to the photoreceptor 1 stably over a long period of time. Therefore, defective cleaning and filming can be suppressed, and a high-quality image can be obtained over a long period of time.
In the printer of this embodiment, a toner having an average circularity of 0.93 or more is used. The surface of the toner particles having an average circularity of 0.93 or more is smooth, and the toner particles and the contact area between the toner particles and the photoreceptor are small, so that the transferability is excellent. However, although the conventional apparatus is inferior in cleaning property, in the printer of the present embodiment, good cleaning property can be obtained by applying the lubricant to the surface of the photoreceptor 5 well.
In the printer of this embodiment, the toner has a volume average particle size of 3 to 8 μm and a ratio (Dv / Dn) of the volume average particle size (Dv) to the number average particle size (Dn) is 1.00 to 1. .40 range is used. Even when a toner having a small particle size in the range of 1.00 to 1.40 and a narrow particle size distribution is used, good cleaning properties can be obtained. By narrowing the particle size distribution of the toner, the charge distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased. It is difficult for such a small particle size toner to be cleaned by overcoming the adhesion force with the photoreceptor 5 in the conventional apparatus. If the particle size is small, the content of the external additive fine particles and the like of the toner tends to be relatively high, so that they are detached from the toner and filming is likely to occur on the photoreceptor 5. However, in the printer of the present embodiment, the brush roller 15 can satisfactorily apply the lubricant to the surface of the photoconductor 5, thereby reducing the friction coefficient of the surface of the photoconductor 5 and improving the cleaning performance of the cleaning blade 47. .
In the printer of this embodiment, toner having a shape factor SF-1 in the range of 100 to 180 and a toner having a shape factor SF-2 in the range of 100 to 180 is used. When the shape of the toner is close to a spherical shape, the contact state between the toner and the toner or the toner and the photosensitive member 5 becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity becomes high. The attracting force with the body 5 is also weakened, and the transfer rate is increased. On the other hand, spherical toner tends to cause poor cleaning in conventional devices, but in the printer of this embodiment, the brush roller 15 satisfactorily applies a lubricant to the surface of the photoconductor 5 to reduce the coefficient of friction on the surface of the photoconductor 5. And good cleaning can be performed. If either of the shape factors SF-1 and SF-2 exceeds 180, the transfer rate is lowered, which is not preferable.
In the printer of this embodiment, the toner has a ratio of the major axis to the minor axis (r2 / r1) in the range of 0.5 to 1.0 and a ratio of the thickness to the minor axis (r3 / r2) of 0. In the range of 0.7 to 1.0, a material satisfying the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 is used. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.
Further, in the printer of this embodiment, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is crosslinked and / or extended in the presence of resin fine particles in an aqueous medium. Toner is used. Since the toner produced by such a polymerization method has the same charge-to-charge mass ratio for each toner particle, the transfer efficiency can be increased and a high-quality image can be obtained. Further, since the amount of transfer residual toner input to the cleaning blade 47 can be reduced, the cleaning property is also improved.

1 is a schematic configuration diagram illustrating an internal configuration of a printer according to an embodiment. FIG. 2 is a schematic configuration diagram illustrating a schematic configuration of a photoconductor unit of the printer. The characteristic view which shows the relationship between applied pressure and an image rank.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer main body 2A, 2B, 2C, 2D Photosensitive unit 3 Transfer belt 5 Photosensitive unit 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 roller 15 Brush roller 16 Solid lubricant 17 Gap management member 18 Waste toner waste toner storage unit 19 Flicker device 20 Reverse paper discharge path 25 Roller pair 26 Paper discharge tray 45a, 45b Transport guide plate 46 Transport roller 47 Cleaning blade 48 Toner transport Auger 49 Charging cleaning roller 50 Bracket 51 Positioning main reference part 52 Front side positioning reference part 53 Back side positioning reference part 55, 56 Separating paper feeding part 58 Paper suction roller 59 Registration roller pair 60 Compression spring P Transfer paper

Claims (10)

An image carrier that carries a toner image, a lubricant application unit that applies a lubricant to the image carrier, a cleaning unit that cleans the surface of the image carrier, and a fine gap between the surface of the image carrier. In a process cartridge that is placed in close proximity and oppositely and is mounted at least integrally with a charging roller to which a voltage in which alternating current is superimposed is applied, and is detachable from the image forming apparatus,
The lubricant application means includes a solid lubricant obtained by solidifying the lubricant, a roller brush that scrapes and scrapes the solid lubricant while rotating, and applies the solid lubricant to the image carrier. A pressing means that presses against the brush, and the brush is provided with 5 to 15 denier brush fibers at a density of 20000 to 100,000 per square inch on the peripheral surface of the rotation support shaft,
The force for pressing the solid lubricant against the brush is 2 to 12 N / m, and the hardness of the solid lubricant is measured with a test force of 50 mN and a load time of 30 seconds , and the load is increased from 0 mN to 30 seconds. A process cartridge having a Martens hardness of 40 to 70 N / mm ² when a test force is obtained .   2. The process cartridge according to claim 1, wherein the material of the brush is polyester.   3. The process cartridge according to claim 1, wherein the brush is insulative.   4. The process cartridge according to claim 1, wherein a peripheral speed ratio of the brush to the image carrier is in a range of 0.8 to 1.2. An image carrier that carries a latent image, a charging roller that is arranged in close proximity to each other while maintaining a minute gap between the surface of the image carrier and a voltage in which an alternating current is superimposed on a direct current is applied to the image carrier. An exposure device that forms an electrostatic latent image; a developing device that converts the electrostatic latent image formed on the image carrier into a toner image; a transfer device that transfers the toner image to a transfer target; and an image on the image carrier. An image forming apparatus comprising: a cleaning device that cleans residual toner remaining on the surface; and a lubricant application unit that applies a lubricant to the surface of the image carrier.
The lubricant application means includes a solid lubricant obtained by solidifying the lubricant, a roller brush that scrapes and scrapes the solid lubricant while rotating, and applies the solid lubricant to the image carrier. A pressing means that presses against the brush, and the brush is provided with 5 to 15 denier brush fibers at a density of 20000 to 100,000 per square inch on the peripheral surface of the rotation support shaft,
The force for pressing the solid lubricant against the brush is 2 to 12 N / m, and the hardness of the solid lubricant is measured with a test force of 50 mN and a load time of 30 seconds, and the load is increased from 0 mN to 30 seconds. image forming apparatus, characterized in that in Martens hardness when set to be the test force is 40~70N / mm ^2.   6. The image forming apparatus according to claim 5, wherein the toner used in the developing device has an average circularity of 0.93 or more.   7. The image forming apparatus according to claim 5, wherein the toner used in the developing device has a volume average particle size of 3 to 8 μm, and a ratio of the volume average particle size (Dv) to the number average particle size (Dn) (Dv / Dn) is in the range of 1.00 to 1.40.   8. The image forming apparatus according to claim 5, wherein the toner used in the developing device 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. Image forming apparatus.   9. The image forming apparatus according to claim 5, wherein the toner used in the developing device has a ratio of the major axis to the minor axis (r2 / r1) in the range of 0.5 to 1.0 and has a thickness. And a minor axis ratio (r3 / r2) in a range of 0.7 to 1.0 and satisfying a relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3.   10. The toner composition according to claim 5, wherein the toner used in the developing device includes a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release material. An image forming apparatus comprising: a toner that is crosslinked and / or extended in the presence of resin fine particles in an aqueous medium.

Images