JP2005164873A - Method for forming image, image forming apparatus and toner used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming an image by which contamination of a charging member can be prevented even when a certain amount of toner is not cleaned in a cleaning step after transfer but remains on a photoreceptor and reaches a charging step, by using a toner in an almost spherical form. <P>SOLUTION: The method for forming an image includes a charging step to charge the surface of an image carrying body 1 by bringing a roller type charging member 2a into contact with the image carrying body 1 under ≤0.23 N/cm contact pressure or in the vicinity of the body 1, then a latent image forming step, a developing step, a transferring step and a cleaning step, with ≥240 mm/sec process speed. The toner used in the developing step has (a) 0.95 to 1.00 average circularity and (b) 2.5 to 6.5 μm weight average particle size (D4), and (c) contains a release agent inside. The distance of the release agent particles from the toner surface is 0.01 to 1.5 μm in average. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a developer containing a toner and an electrostatic latent image formed on the surface of the image carrier by an exposure unit after charging the surface of the image carrier by bringing a charging member into contact with or close to the image carrier such as a photoconductor. The present invention relates to an image forming method for making a visible image by the above. The present invention also relates to an image forming apparatus for executing the image forming method, and a toner used in the image forming method.

An image forming apparatus using an electrophotographic process includes a photosensitive member as a latent image carrier, charges the surface of the photosensitive member by discharging, charges the surface of the photosensitive member to form an electrostatic latent image, The electrostatic latent image is supplied with toner to be visualized, and the formed visible image on the surface of the photoreceptor is transferred onto the transfer paper surface, and then fixed and discharged.
As a means for charging the surface of the photoconductor, a non-contact method using corona discharge using a corona wire has been conventionally used. However, since the applied voltage is high and a large amount of ozone or nitrogen oxide (NOx) is generated, Deterioration of the photoreceptor and adverse effects on the environment are problems.
As an alternative to this, a contact or proximity method is often used in which a charging member such as an elastic roller made of a medium resistance material is brought into contact with the surface of the photoconductor or close to it with a predetermined gap and charged by applying voltage from the outside. It is supposed to be. The contact or proximity method requires a low applied voltage and generates almost no ozone or NOx.

  On the other hand, in recent years, there has been an increasing demand for higher image quality, and in order to realize particularly high-definition color image formation, toner particles are being made smaller and spherical. The reproducibility of dots is improved by reducing the particle size, and the developability and transferability can be improved by making the particles spherical. Since it is very difficult to produce such a small particle size and spherical toner by the conventional kneading and pulverization method, the polymerization produced by suspension polymerization method, emulsion polymerization method, dispersion polymerization method, etc. Toner is being adopted.

As a problem when using a small particle size, spherical toner, there is toner that remains on the photoreceptor without being transferred although the transfer rate is high. May pass between the photosensitive member and the blade, resulting in poor cleaning. There is a problem in that the toner that has not been cleaned by the cleaning blade adheres to and contaminates the surface of the charging member that is in contact with or close to the photoreceptor thereafter.
The polymerized toner can be made to contain wax or the like as a release agent in the toner in order to improve the releasability from the fixing member at the time of fixing the image onto the transfer paper. This eliminates the need for an oil application process to the fixing member to prevent the offset phenomenon that occurs in the fixing process, and simplifies the apparatus configuration. In particular, when printing on a resin film such as an OHP sheet, oil is applied to the sheet. Problems such as adhesion and changes in the color tone of the image are eliminated. However, as described above, when the toner that has passed through the cleaning blade adheres to the surface of the charging member, a low molecular weight component such as wax contained in the toner appears over time, and is easily fused to the surface of the charging member. Become. The toner fused to the surface of the charging member remains without being cleaned even if a member for cleaning the surface of the charging member such as a cleaning brush or a cleaning pad is provided, and causes uneven charging on the surface of the photoreceptor.

In order to prevent surface contamination of the charging member when using a small particle size and spherical toner, for example, there is a proposal (for example, see Patent Document 1) that defines the contact pressure of the charging member to the photosensitive member. When the photosensitive member and the charging roller as the charging member are driven to rotate, if the contact pressure of the charging roller is low, the photosensitive member and the charging roller slip at the contact surface, and the toner passing through the cleaning device is charged by the charging member. Since it is rubbed against the surface, in order to prevent this, it is said that a certain level of contact pressure is good.
In addition, it is disclosed that toner having a high degree of circularity can pass through the cleaning device and hardly adhere to the surface of the charging member, thereby preventing contamination of the charging member (see, for example, Patent Document 2). .

JP-A-10-213950 JP 2002-278220 A

However, none of the above proposals consider the presence state of a release agent such as wax, which is a toner component that easily causes toner fusion, in the toner.
In addition, since the problem of surface contamination of the charging member can be seen in both the contact method and the proximity method, a means that can solve this problem as a whole is required regardless of the charging method.

  In view of the above problems, the present invention uses a nearly spherical toner, so that even if there is toner remaining on the photoreceptor without being cleaned in the cleaning process after transfer and reaching the charging process, It is an object of the present invention to provide an image forming method capable of preventing contamination. Another object of the present invention is to provide an image forming apparatus that executes the image forming method and does not generate an abnormal image due to uneven charging, and a toner that is suitably used in the image forming method.

In order to solve the above problems, the present invention is characterized by the following.
1. The present invention includes a charging step of charging a surface of an image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or in proximity to the image carrier at a contact pressure of 0.23 N / cm or less, and charging A latent image forming step of forming an electrostatic latent image on the surface of the image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and the surface of the image carrier In the image forming method including a transfer step of transferring the toner image formed on the transfer member to the transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, the process speed is 240 mm / sec or more, and the development The toner used in the process
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) contains a release agent, almost all of the release agent is present inside the toner, and the release agent present on the toner surface imparts lubricity to the surface of the image carrier in the cleaning step;
(D) The release agent inside the toner oozes out on the toner surface in a state of being pressurized between the charging member and the image carrier or between the charging member and the member for cleaning the charging member. This is an image forming method that does not take advantage.

2. According to another aspect of the present invention, there is provided a charging step of charging a surface of the image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or approaching the image carrier with a contact pressure of 0.23 N / cm or less. A latent image forming step of forming an electrostatic latent image on the surface of the charged image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and an image carrier In an image forming method including a transfer step of transferring a toner image formed on the body surface to a transfer target and a cleaning step of cleaning the image carrier surface after the transfer step, the process speed is 240 mm / sec or more, The toner used in the development step is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) An image forming method in which a release agent is contained inside and the distance from the release agent dispersed particles to the toner surface is 0.01 to 1.5 μm on average.

3. According to another aspect of the present invention, there is provided a charging step of charging a surface of the image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or approaching the image carrier with a contact pressure of 0.23 N / cm or less. A latent image forming step of forming an electrostatic latent image on the surface of the charged image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and an image carrier In an image forming method including a transfer step of transferring a toner image formed on the body surface to a transfer target and a cleaning step of cleaning the image carrier surface after the transfer step, the process speed is 240 mm / sec or more, The toner used in the development step is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) An image forming method containing a release agent inside and having a dynamic friction coefficient of 0.18 to 0.45.

4). The average circularity of the toner used in the developing process is 0.98 to 1.00.
5). In the charging step, when the charging member is brought close to the image carrier, a gap between the surface of the charging member and the surface of the image carrier is set to (2 × D4) to 70 μm.

6). In the image forming method, the release agent contained in the toner is rice wax and / or ester wax.
7). In the image forming method, the release agent contained in the toner is dispersed in the toner with an average dispersion diameter of 0.3 to 1.0 μm.

8). In the image forming method, the toner is formed by externally adding hydrophobic hydrophobized inorganic oxide fine particles.
9. In the image forming method, the toner is formed by externally adding a lubricant.
10. In the image forming method, the toner contains a charge control agent made of a fluorine-containing compound.

11. In the image forming method, the toner includes, in an aqueous medium, a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. It is obtained by crosslinking and / or elongation reaction.

12 The present invention also provides an image carrier for carrying an electrostatic latent image, a charging means for uniformly charging the surface of the image carrier, and exposing the surface of the charged image carrier based on image data to An exposure means for writing a latent image, a developing means for supplying toner to the electrostatic latent image formed on the surface of the image carrier and making it visible, and a transfer for transferring the toner image on the surface of the image carrier to the transfer target An image forming apparatus that executes any one of the above image forming methods in an image forming apparatus that includes a cleaning unit and a cleaning unit that cleans the surface of the image carrier after transfer.

13. Furthermore, the present invention provides a charging step of charging the surface of the image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less. A latent image forming step of forming an electrostatic latent image on the surface of the charged image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and an image carrier Used in an image forming method having a transfer step of transferring a toner image formed on the surface of a body to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more. Toner,
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) contains a release agent, almost all of the release agent is present inside the toner, and the release agent present on the toner surface imparts lubricity to the surface of the image carrier in the cleaning step;
(D) The release agent inside the toner oozes out on the toner surface in a state of being pressurized between the charging member and the image carrier or between the charging member and the member for cleaning the charging member. It is a toner that does not come out.

14 Furthermore, the present invention provides a charging step of charging the surface of the image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less. A latent image forming step of forming an electrostatic latent image on the surface of the charged image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and an image carrier Used in an image forming method having a transfer step of transferring a toner image formed on the surface of a body to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more. Toner,
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) A toner containing a release agent inside and having an average distance from the release agent dispersed particles to the toner surface of 0.01 to 1.5 μm.

15. According to another aspect of the present invention, there is provided a charging step of charging a surface of the image carrier by applying a voltage to the charging member by bringing a roller-shaped charging member into contact with or approaching the image carrier with a contact pressure of 0.23 N / cm or less. A latent image forming step of forming an electrostatic latent image on the surface of the charged image carrier, a developing step of supplying toner to the electrostatic latent image formed on the surface of the image carrier to make a visible image, and an image carrier Used in an image forming method having a transfer step of transferring a toner image formed on the surface of a body to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more. Toner,
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) A toner containing a release agent inside and having a dynamic friction coefficient of 0.18 to 0.45.

16. The toner has an average circularity of 0.98 to 1.00.
17. In the toner, the release agent is rice wax and / or ester wax.
18. In the toner, the release agent is dispersed in the toner with an average dispersion diameter of 0.3 to 1.0 μm.

19. The toner is characterized by externally adding hydrophobized inorganic oxide fine particles.
20. The toner is characterized by externally adding a lubricant.
21. The toner contains a charge control agent made of a fluorine-containing compound.

22. In the toner, a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent is crosslinked and / or extended in an aqueous medium. It is characterized by being obtained.

  According to the present invention, by using a nearly spherical toner, the toner remaining on the surface of the image carrier without being cleaned in the cleaning process is prevented from adhering and fusing to the charging member surface, and a stable charging process is performed. It is possible to provide an image forming method capable of In addition, it is possible to provide a toner that is suitably used in the present image forming method, thereby stably obtaining a high-quality and high-definition image.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus for executing the image forming method of the present invention. FIG. 2 is a diagram showing a configuration around the photosensitive member of the image forming apparatus shown in FIG.
A charging device 2, an exposure device 3, a developing device 4, a transfer device 6, a fixing device 7 and a cleaning device 8 are arranged around the photoreceptor 1 as an image carrier.

  The photoreceptor 1 is manufactured using amorphous metal having photoconductivity, amorphous metal such as amorphous selenium, organic compounds such as bisazo pigment and phthalocyanine pigment. Considering the environment and post-treatment after use, it is preferable to use a photoconductor produced using an organic compound.

The charging device 2 includes a charging roller 2a, a cleaning pad 2b in contact with the charging roller 2a for cleaning, and a power supply (not shown) connected to the charging roller 2a. A high voltage is applied to the charging roller 2a, a predetermined voltage is applied between the charging roller 2a having a curvature and the photoconductor 1, and a corona discharge is generated between the photoconductor 1 and the surface of the photoconductor 1 Are uniformly charged.
The charging roller 2a is formed by forming an elastic layer made of rubber, sponge or the like on the outer periphery of a metal core made of metal such as stainless steel, and further forming a surface layer made of fluorine resin or the like on the outer periphery. The elastic layer can be formed by dispersing conductive powder such as carbon black in silicone rubber, EPDM, or the like, and the volume resistance is adjusted to 10 ⁵ to 10 ⁹ Ω · cm. The surface roughness of the charging roller 2a is preferably 1.5 to 18.0 μm in terms of Rz.
The detailed configuration of the charging device 2 will be described later.

  The exposure device 3 converts data read by a scanner in the reading device 20 and an image signal sent from the outside such as a PC (not shown), scans the laser beam 3a with a polygon motor, and reads the image signal read through the mirror. Based on this, an electrostatic latent image is formed on the photoreceptor 1.

The developing device 4 includes a developer carrier 4a that carries a developer and supplies the developer 1 to the photoreceptor 1, a toner supply chamber, and the like. It has a cylindrical developer carrier 4a arranged at a minute distance from the photosensitive member 1, and a developer regulating member for regulating the amount of developer on the developer carrier 4a. The developer carrier 4a includes a hollow cylindrical developer carrier 4a that is rotatably supported, and a magnet roll fixed coaxially with the developer carrier 4a. The developer is magnetically attracted to the outer peripheral surface of the carrier 4a and conveyed. The developer carrier 4a is electrically conductive and is made of a nonmagnetic member, and is connected to a power source for applying a developing bias. A voltage is applied from the power source between the developer carrying member 4a and the photoreceptor 1, and an electric field is formed in the developing region.
Although the above has described a developing device using a two-component developer, the present invention is not limited to this, and a developing device using a one-component developer may be used.

  The transfer device 6 includes a transfer belt 6a, a transfer bias roller 6b, and a tension roller 6c. The transfer bias roller 6b is configured by providing an elastic layer on the surface of a core metal such as iron, aluminum, and stainless steel. The transfer bias roller 6 b is applied with a necessary pressure on the photosensitive member 1 side in order to bring the recording paper into close contact with the photosensitive member 1. The transfer belt 6a can obtain an effect by selecting various heat-resistant materials as a base material, and can be composed of, for example, a seamless polyimide film. A configuration in which a fluororesin layer is provided on the outside can be employed. Further, if necessary, a silicone rubber layer may be provided on the polyimide film, and a fluororesin layer may be provided thereon. Inside the transfer belt 6a, a tension roller 6c is provided to drive and stretch the transfer belt 6a.

  The fixing device 7 includes a fixing roller having a heater that is a heating unit such as a halogen lamp, and a pressure roller that is in pressure contact. In the fixing roller, an elastic layer such as silicone rubber is provided on the surface of the core metal to a thickness of 100 to 500 μm, preferably 400 μm, and for the purpose of preventing adhesion due to toner viscosity, a resin surface layer having good releasability such as fluororesin Is formed. The resin surface layer is composed of a PFA tube or the like, and its thickness is preferably about 10 to 50 μm in consideration of mechanical deterioration. A temperature detecting means is provided on the outer peripheral surface of the fixing roller, and the heater is controlled so as to keep the surface temperature of the fixing roller substantially constant within a range of about 160 to 200 ° C. In the pressure roller, the core metal surface is coated with an anti-offset layer such as tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA) or polytetrafluoroethylene (PTFE). Similar to the fixing roller, an elastic layer such as silicone rubber may be provided on the surface of the core metal.

  The cleaning device 8 includes a cleaning blade 8a as a cleaning unit for toner remaining on the surface of the photoreceptor 1 after the transfer process. Further, a toner collection blade 8d for collecting the cleaned toner and a collection coil 8c for conveying the toner are provided. Further, a toner collection box (not shown) is provided. The cleaning blade 8a is made of a material such as metal, resin, rubber, etc., and rubbers such as fluorine rubber, silicone rubber, butyl rubber, butadiene rubber, isoprene rubber, and urethane rubber are preferably used. Of these, urethane rubber is particularly preferable.

In the image forming method of the present invention, the charging method is a contact method in which the charging roller 2a is brought into contact with the surface of the photosensitive member 1, and the charging roller 2a and the photosensitive member 1 are referred to as a predetermined gap (hereinafter referred to as “gap”). ) May be used.
FIG. 3 is a diagram illustrating a configuration of the contact-type charging device 2. Bearings 210 that support the cored bar 201 of the charging roller 2a are provided at both ends in the longitudinal direction, and the charging roller 2a is pressed against the photosensitive member 1 with a constant pressure by springs 204 attached to the bearings 210. And is in contact with the surface of the photoreceptor 1. The contact pressure is 0.23 N / cm or less. Thus, the toner that passes through the cleaning device 8 and remains on the surface of the photoreceptor 1 is less likely to be crushed at the nip portion with the charging roller 2a. When the contact pressure exceeds 0.23 N / cm, the toner is crushed and the release agent contained in the toner oozes out, and is rubbed against the surface of the charging roller 2a to be easily attached.

  As a method for measuring the contact pressure, as shown in FIG. 5, a folded thin plate 51a made of SUS is inserted as shown in the nip portion between the photoreceptor 1 and the charging roller 2a, and the width is 1 cm. The force required to pull the thin plate 51b between the thin plates 51a in the direction of the arrow is measured by the spring 52 alone.

  Further, as shown in FIG. 3, a driving gear 220 is fixed to one end of a core bar 201 of the charging roller 2a, and a driving force from a motor (not shown) is transmitted to the charging roller 2a. It is designed to rotate at a linear speed of. The voltage is applied to the charging roller 2a by applying, for example, DC-700V to the core bar 201 with constant voltage control, and applying AC voltage with constant current control.

FIG. 4 is a diagram illustrating a configuration of the proximity charging device 2. Gap holding members 203 are provided at both ends of the elastic roller portion 202 provided with the elastic layer of the charging roller 2a and not on the image forming area of the photoreceptor 1. The gap holding member 203 can be provided by, for example, winding an adhesive sheet having one side made of polyester or polyethylene terephthalate on the adhesive side and winding it in the circumferential direction with the adhesive side facing down.
As in the case shown in FIG. 3, the charging roller 2 a is pressed against the photosensitive member 1 with a certain pressure by a spring 204 attached to the bearing 210 of the core bar 201. As a result, the gap holding members 203 provided at both ends of the elastic roller portion 202 come into contact with the surface of the photosensitive member 1, respectively, and the surface of the elastic roller portion 202 where the gap holding member 203 is not provided and the surface of the photosensitive member 1. A gap G is formed in the contact portion, and that portion becomes non-contact.
The driving method of the charging roller 2a and the applied voltage are the same as in the contact method.

  In the proximity charging device 2, the gap G is preferably in the range of (2 × D4) μm to 70 μm, where D4 is the weight average particle diameter of the toner used for image formation. By setting the gap G to (2 × D4) μm or more, it is possible to prevent the surface of the charging roller 2a from coming into contact with the toner attached to the surface of the photoreceptor 1, and to effectively prevent contamination by the toner. On the other hand, if the gap G exceeds 70 μm, the distance between the surface of the charging roller 2a and the surface of the photosensitive member is increased, so that the discharge energy increases and the generation amount of ozone and NOx increases.

The image forming method of the present invention is characterized by using a toner satisfying the following (a) to (c) in the developing step.
(A) The average circularity of the toner is 0.95 to 1.00.
The average circularity of the toner is a value obtained by optically detecting particles and dividing by the perimeter of an equivalent circle having the same projected area. Specifically, the measurement is performed using a flow type particle image analyzer (FPIA-2000; manufactured by Sysmex Corporation). In a predetermined container, 100 to 150 mL of water from which impure solids are removed in advance is added, 0.1 to 0.5 mL of a surfactant is added as a dispersant, and about 0.1 to 9.5 g of a measurement sample is further added. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the concentration and dispersion of the dispersion are set to 3,000 to 10,000 / μL, and the shape and distribution of the toner are measured.
A toner having an average circularity of 0.95 to 1.00 has a projected shape close to a circle, is excellent in dot reproducibility, has a high transfer rate, and can provide a high-quality image. Further, since the transfer rate is high, the amount of toner remaining on the surface of the photoreceptor 1 after the transfer process can be reduced. On the other hand, since the toner has a charge amount distribution, there is a toner that does not have a sufficient charge amount and remains on the surface of the photoreceptor 1 without being transferred, and is a toner having a high average circularity as described above. There is a problem that the cleaning blade 8a is easily slipped through.
As described above, the contact pressure of the charging roller 2a against the surface of the photoconductor 1 is set to 0.23 N / cm or less so that the toner remaining on the surface of the photoconductor 1 is not easily crushed at the nip portion with the charging roller 2a. Under such pressure, since the average circularity of the toner is high as described above, the toner can pass through the charging roller 2a without receiving much stress. In addition, as the contact pressure of the charging roller 2a is lower, such slip-through is more likely to occur. If the proximity method has a certain gap between the photosensitive member 1 and the charging roller 2a, the surface of the charging roller 2a can be further increased. Toner adhesion can be prevented.
On the other hand, if the average circularity is less than 0.95, the toner is separated from the spherical shape, the dot reproducibility is deteriorated, and the number of contact points to the photoreceptor 1 is increased. Since the rate decreases, the image quality deteriorates. Further, the toner that remains on the surface of the photoreceptor 1 after the transfer and passes through the cleaning blade 8a is likely to adhere to the surface of the charging roller 2a.

(B) The toner has a weight average particle diameter (D4) of 2.5 to 6.5 μm.
By using a toner having a small weight average particle size, dot reproducibility can be improved and dense development can be performed on the electrostatic latent image. On the other hand, the small particle size toner is difficult to be cleaned by the cleaning blade 8a and may remain on the surface of the photoreceptor 1. In the present invention, the weight average particle diameter of the toner is set to 6.5 μm or less so that the charging roller 2a can pass through without much stress. Such a tendency becomes stronger as the particle diameter is smaller, but if the particle diameter is less than 2.5 μm, the toner particles are aggregated and are hardly slipped through. If the weight average particle size is less than 2.5 μm, the two-component developer causes the toner to be fused to the surface of the magnetic carrier during long-term agitation in the developing device, thereby reducing the charging ability of the magnetic carrier. In the case of using the toner, another problem that the filming of the toner on the developing roller and the fusion of the toner to a member such as a blade for thinning the toner easily occur.

The weight average particle diameter (D4) can be measured using a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter, Inc.) as a measuring device.
The measuring method is as follows. First, 0.1 to 5 ml of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 to 150 ml of an electrolytic aqueous solution. Here, the electrolytic solution was prepared by preparing approximately 1% NaCl aqueous solution using primary sodium chloride, and ISOTON R-II (manufactured by Coulter Scientific Japan) was used. Further, 2 to 20 mg of a measurement sample was added thereto, suspended in an electrolytic solution, and subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using the measurement apparatus, the volume and number of toner particles in the sample were measured for each channel using a 100 μm aperture as the aperture, and the volume distribution and number distribution of the toner were calculated. Then, the weight-based toner weight average particle diameter (D4) obtained from the volume distribution of the toner particles (the median value of each channel is a representative value for each channel) was obtained.
In addition, as a channel, it is 2.00-2.52 micrometer; 2.52-3.17 micrometer; 3.17-4.00 micrometer; 4.00-5.04 micrometer; 5.04-6.35 micrometer; 6.35- 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32. 00 μm; 13 channels from 32.00 to 40.30 μm were used.

(C) The toner contains a release agent, and almost all of the release agent is present in the toner, and the release agent present on the toner surface imparts lubricity to the surface of the photoreceptor 1 in the cleaning process. ,
(D) The release agent inside the toner soaks into the toner surface in a state of being pressurized between the charging roller 2a and the photosensitive member 1 or between the charging roller 2a and the cleaning pad 2b for cleaning the charging roller 2a. I ’m not going out.
A toner having a configuration in which almost all of the release agent to be added is present in the toner and the release agent does not ooze out on the toner surface even when the toner is pressurized at the nip portion between the charging roller 2a and the photoreceptor 1. By using this, the surface contamination of the charging roller 2a can be effectively prevented. Similarly, between the charging roller 2a and the cleaning pad 2b for cleaning the charging roller 2a, it is possible to effectively prevent the surface of the charging roller 2a from being contaminated by using a toner having a structure in which the release agent does not ooze out. .
On the other hand, the release agent present on the toner surface imparts lubricity to the surface of the photoreceptor 1 in the cleaning process, and therefore, the cleaning performance of the toner can be improved by the cleaning blade 8a that rubs the surface of the photoreceptor 1. it can.

The toner used in the development step may satisfy the following (c ′) instead of the above (c) and (d).
(C ′) The toner contains a release agent, and the average distance between the release agent particles and the toner surface is 0.01 to 1.5 μm.
The presence state of the release agent inside the toner can be confirmed as follows.
The toner was embedded in an epoxy resin and sectioned to a thickness of 100 nm by a microtome. Next, the section was stained with a 0.5% aqueous solution of ruthenium tetroxide, and the section was observed with a transmission electron microscope (TEM). As shown in the schematic diagram of FIG. 6, resin components other than the release agent are dyed, but the release agent is not dyed. Then, the shortest distance d among the distances from the outer periphery of the release agent dispersed particles to the toner surface was measured as one index representing the dispersion state of the release agent particles inside the toner. When a plurality of release agent dispersed particles could be confirmed in one toner particle, the distance d to each release agent dispersed particle was measured, and then the average value of the distances d was obtained.

  The release agent is contained in the vicinity of the surface of the toner particles because it is contained in order to enhance the releasability of the fixing member that comes into contact with the toner in the fixing step. However, in the toner that passes through the cleaning process and remains on the surface of the photoreceptor 1, if the release agent is exposed on the toner surface, the toner is charged to the charging roller 2 a due to the presence of the release agent that is a low molecular weight component. It adheres to the surface and is easily fused even under the influence of slight heat. Therefore, the release agent particles are preferably present at a certain distance from the toner surface, and the distance d is preferably in the range of 0.01 to 1.5 μm on average. If the average distance d exceeds 1.5 μm, a large amount of the release agent is present inside the toner, and the effect of improving the releasability at the time of fixing cannot be obtained sufficiently. If the average distance d is less than 0.01 μm, the amount of the release agent exposed on the toner surface increases, so that the toner that has passed through the cleaning blade 8a is charged by the release agent exposed on the surface. The surface of the roller 2a is violently contaminated, which causes further toner adhesion to the surface of the charging roller 2a. Further, if the release agent is exposed on the toner surface, the toners easily aggregate and are difficult to slip through the charging roller 2a.

In addition, the toner used in the development process may satisfy the following (c ″) instead of the above (c), (d), and (c ′).
(C ″) A release agent is contained inside, and the dynamic friction coefficient of the toner is 0.18 to 0.45.
The dynamic friction coefficient of the toner is measured by applying a load of 6 t / cm ² to a toner having a mass of 3 g and forming a disk-shaped pellet having a diameter of 40 mm using a fully automatic friction wear analyzer manufactured by Kyowa Interface Science Co., Ltd. be able to. At this time, a 3 mm stainless sphere point contact is used as the contact.
In general, the dynamic coefficient of friction of the binder resin occupying most of the toner component is about 0.5, and about 0.1 for the release agent such as wax. Therefore, when the content of the release agent is the same, the difference in the dynamic friction coefficient of the toner is caused by the difference in the amount of the release agent present on the toner surface. If the coefficient of dynamic friction is less than 0.18, the amount of the release agent present on the toner surface is large, so that the toner that has passed through the cleaning blade 8a vigorously contaminates the surface of the charging roller 2a with the release agent exposed on the surface. This further causes toner adhesion to the surface of the charging roller 2a. Further, if the release agent is exposed on the toner surface, the toners easily aggregate and are difficult to slip through the charging roller 2a. On the other hand, if the dynamic friction coefficient is in the range of 0.18 to 0.45, a release agent is present in the vicinity of the toner surface, and the amount of the release agent does not induce toner adhesion on the surface of the charging roller 2a. It is an amount. On the other hand, when the dynamic friction coefficient exceeds 0.45, there is almost no release agent on the toner surface, and the effect of improving the releasability at the time of fixing cannot be obtained.

  In the image forming method of the present invention using the toner having the above configuration in the developing step, the process speed is set to 240 mm / sec or more. When the process speed is 240 mm / sec or more, contamination of the surface of the charging roller 2a becomes a significant problem. When toner is rubbed in an image forming process such as a development process or a cleaning process, a large amount of frictional heat is generated at such a high speed, and as a result, toner adhesion to the surface of the charging roller 2a is accelerated. . Therefore, such a problem is effectively prevented by the configuration of the present invention.

As the release agent, a low melting point wax having a melting point of 50 to 120 ° C. works between the fixing member such as a fixing roller and the toner interface more effectively as a release agent in the dispersion with the binder resin, As a result, it is effective against high temperature offset without applying a release agent such as oil to the fixing roller. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .
These may be used alone or in combination of two or more. Among these, it is preferable to use rice wax and / or ester wax because of good dispersibility of the release agent in the toner particles.
The addition amount of the release agent is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin component of the toner.

The average dispersion diameter of the release agent is preferably 0.3 to 1.0 μm. As described above, since the release agent is encapsulated in a state of being finely dispersed inside the toner particles, the gloss and transparency of the color toner are excellent, and a clear and excellent color reproduction image is obtained. be able to. When the average dispersion diameter is smaller than 0.3 μm, sufficient releasability cannot be expressed in the fixing process. On the other hand, if the average dispersion diameter is larger than 1.0 μm, the toner exhibits agglomeration and fluidity is deteriorated or filming occurs. In addition, color reproducibility and glossiness are remarkably lowered in color toners. End up.
Incidentally, the average dispersion diameter of the release agent was obtained by taking a photographic image of the release agent particles in the toner particles using a transmission electron microscope (TEM) as described above, and using an image analyzer Luzex IIIU (Nireco Corporation). Obtained by image analysis.

Other constituent materials of the toner used in the present invention will be described in detail.
(Modified polyester)
The toner according to the present invention contains a modified polyester (i) as a binder resin. The modified polyester (i) refers to a state in which a bonding group other than an ester bond is present in the polyester resin, or resin components having different configurations are bonded to the polyester resin by a covalent bond, an ionic bond, or the like. Specifically, the polyester terminal is modified by introducing a functional group such as a carboxylic acid group or an isocyanate group that reacts with a hydroxyl group into the polyester terminal and further reacting with an active hydrogen-containing compound.

  Examples of the modified polyester (i) include urea-modified polyester obtained by a reaction between a polyester prepolymer (A) having an isocyanate group and amines (B). As the polyester prepolymer (A) having an isocyanate group, a polyester having a polycondensate of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC) and having an active hydrogen group is further added to a polyvalent isocyanate compound (PIC). And those reacted with. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

The urea-modified polyester is produced as follows.
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.

  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; 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 modified polyester (i) used in the present invention is produced by a one-shot method or a prepolymer method. The weight average molecular weight of the modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. The peak molecular weight at this time is preferably 1000 to 10000. When the molecular weight is less than 1000, the elongation reaction hardly occurs, the elasticity of the toner is small, and as a result, the resistance to hot offset deteriorates. On the other hand, when it exceeds 10,000, the problem in production becomes high in the deterioration of fixability, particle formation and pulverization. The number average molecular weight of the modified polyester (i) is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color device are deteriorated.
In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B) to obtain the modified polyester (i), a reaction terminator is used as necessary to adjust the molecular weight of the resulting urea-modified polyester. be able to. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).
The molecular weight of the polymer produced can be measured using gel permeation chromatography (GPC) with THF as a solvent.

(Unmodified polyester)
In the present invention, not only the modified polyester (i) is used alone, but also the unmodified polyester (ii) can be contained as a binder resin component together with the (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to single use. Examples of (ii) include polycondensates of polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) similar to the polyester component of (i), and preferred ones are also the same as (i). . (Ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. It is preferable that (i) and (ii) are at least partially compatible in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. When (ii) is contained, the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. When the weight ratio of (i) 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 peak molecular weight of (ii) is usually 1000 to 10,000, preferably 2000 to 8000, and more preferably 2000 to 5000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 10,000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is preferably 1 to 5, more preferably 2 to 4. Since a high acid value wax is used as the wax, the low acid value binder leads to electrification and high volume resistance, so that it is easy to match the toner used for the two-component developer.

The glass transition point (Tg) of the binder resin is usually 35 to 70 ° C, preferably 55 to 65 ° C. If it is less than 35 ° C., the heat resistant storage stability of the toner is deteriorated, and if it exceeds 70 ° C., the low-temperature fixability is insufficient. Since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the toner of the present invention tends to have good heat storage stability even when the glass transition point is low, as compared with known polyester-based toners. Show.
The glass transition point (Tg) can be measured with a differential scanning calorimeter (DSC).

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

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded 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.
Among these, it is preferable to use a fluorine-containing compound having a fluorinated alkyl group as shown in Chemical Formulas 1 and 2 below. Since such a charge control agent is excellent in negative chargeability, even if toner passes through the cleaning blade 8a, it is difficult to adhere to the surface of the charging roller 2a to which a negative voltage is applied.

(In the formula, M ^{k +} ; Na ⁺ , K ⁺ , Li ⁺ , Ca ²⁺ , Ba ²⁺ , Zn ²⁺ , Fe ²⁺ , Co ²⁺ , Cr ²⁺ , n; positive integer, k; any of 1, 2, 3 Integer)

(Wherein, X: —SO ₂ —, —CO—, R ₁ ; H, alkyl group or aryl group having 1 to 10 carbon atoms, n, m; positive integer)

The amount of the charge control agent used is determined based on 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. However, it is preferably 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 flowability of the developer is lowered, and the image density is lowered. Invite.
The charge control agent and the release agent already described can be melt-kneaded together with the master batch and the binder resin, or of course, may be added when dissolved and dispersed in an organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The amount of the inorganic fine particles added 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.
Such external additives can be surface treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
In particular, it is preferable to use inorganic oxide fine particles such as silica and titanium oxide subjected to the hydrophobic treatment. Since such inorganic fine particles have an excellent effect of improving the fluidity of the toner, the toner remaining on the surface of the photoreceptor 1 is likely to slip through even on the surface facing the charging roller 2a, thereby preventing adhesion to the surface of the charging roller 2a. Can do.

In order to further improve the effect of preventing adhesion to the surface of the charging roller 2a, a lubricant may be externally added to the toner. Examples of the lubricant include fatty acid metals such as lead oleate, zinc oleate, copper oleate, zinc stearate, cobalt stearate, iron stearate, copper stearate, zinc palmitate, copper palmitate and zinc linolenate. Fluorine such as salts, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, polytrifluorochloroethylene, dichlorodifluoroethylene, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-oxafluoropropylene copolymer Based resins.
In addition to this, the effect of externally adding the lubricant to the toner is that the lubricant is detached from the surface of the toner that has been stressed by the cleaning blade 8a in the cleaning process, and a thin film is formed on the surface of the photoreceptor 1 to form a photoreceptor. One example is to reduce the friction coefficient of one surface. As a result, an effect of improving the transfer property and the cleaning property can be obtained, so that the amount of residual toner that passes through the cleaning blade 8a and reaches the surface facing the charging roller 2a can be reduced.

  The addition amount of the lubricant is preferably in the range of 0.1 to 2.0 wt% of the toner. If the addition amount is less than 0.1%, a sufficient effect as a lubricant cannot be obtained. On the other hand, if it exceeds 2.0%, on the contrary, it adheres to the surface of the charging roller 2a and becomes a contaminant, such being undesirable.

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)
The toner according to the present invention is obtained by crosslinking a toner material solution 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 in an aqueous medium. Alternatively, it can be produced by an extension reaction.
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 salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol 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 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), 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.
In the present invention, the average circularity of the toner can be controlled by the strength of liquid agitation before the removal of the organic solvent and the removal time of the organic solvent. By slowly removing the solvent, the shape approximates a perfect circle at 0.98 or more when expressed in average circularity, and by removing the solvent with strong stirring in a short time, the shape becomes irregular or irregular, and the average circularity is When expressed, it becomes 0.90 to 0.95. By carrying out the liquid removal medium while stirring the emulsion after being emulsified and dispersed in an aqueous medium and further reacting in the liquid removal medium with a strong stirring force at a temperature of 30 to 50 ° C., the average circularity Control is possible and shape control in the range of 0.85 to 0.99 is possible. This is thought to be due to volumetric shrinkage caused by abrupt removal of an organic solvent such as ethyl acetate contained in the granulation.
The liquid medium can be removed by spraying the emulsified dispersion liquid in a dry atmosphere to completely remove the organic solvent to form toner fine particles, and a method of evaporating and removing the aqueous dispersant. . The dry atmosphere in which the emulsified dispersion is sprayed includes air, nitrogen, carbon dioxide, combustion gas, etc. heated gas, preferably various air streams heated to a temperature higher than the boiling point of the highest boiling liquid medium used. Used. High-quality toner can be obtained by short-time processing such as spray dryer, belt dryer and rotary kiln.
The time until the dispersion after the reaction is desolvated after the reaction is preferably a short time, but is usually within 25 hours.

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.

The toner produced as described above can also be used as a one-component magnetic toner that does not use a magnetic carrier or a non-magnetic toner.
When used in a two-component developer, it may be used by mixing with a magnetic carrier, and the magnetic carrier is a ferrite containing a divalent metal such as iron, magnetite, Mn, Zn, Cu, A volume average particle size of 20 to 100 μm is preferred. If the average particle size is less than 20 μm, carrier adhesion is likely to occur on the photoreceptor 1 during development, and if it exceeds 100 μm, the miscibility with the toner is low and the charge amount of the toner is insufficient, resulting in poor charging during continuous use. Cheap. In addition, Cu ferrite containing Zn is preferable because of its high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus 100. The resin for coating the magnetic carrier is not particularly limited, and examples thereof include silicone resin, styrene-acrylic resin, fluorine-containing resin, and olefin resin. In the manufacturing method, the coating resin may be dissolved in a solvent, sprayed into a fluidized bed and coated on the core, or the resin particles are electrostatically attached to the core particles and then thermally melted for coating. It may be a thing. The resin to be coated has a thickness of 0.05 to 10 μm, preferably 0.3 to 4 μm.

  EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. In addition, a part shows a weight part.

~ Synthesis of organic fine particle emulsion ~
Production Example 1
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 83 parts of styrene, 83 parts of methacrylic acid, When 110 parts of butyl acrylate and 1 part of ammonium persulfate were added and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours to give a vinyl resin (a copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). An aqueous dispersion [fine particle dispersion 1] was obtained. The volume average particle diameter of the [fine particle dispersion 1] measured with a laser diffraction particle size distribution analyzer (LA-920, manufactured by Shimadzu Corporation) was 105 nm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The resin content had a Tg of 59 ° C. and a weight average molecular weight of 150,000.

-Adjustment of aqueous phase-
Production Example 2
990 parts of water, 99 parts of [fine particle dispersion 1], 35 parts of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7 manufactured by Sanyo Chemical Industries) and 60 parts of ethyl acetate were mixed and stirred to give a milky white liquid. Obtained. This is designated as [Aqueous Phase 1].

~ Synthesis of low molecular weight polyester ~
Production Example 3
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl 2 parts of tin oxide was added, reacted at 230 ° C. under normal pressure for 8 hours, and further reacted for 5 hours under reduced pressure of 10-15 mmHg. Then, 44 parts of trimellitic anhydride was added to the reaction vessel, and 1 part at 180 ° C. at normal pressure. After reacting for 8 hours, [low molecular weight polyester 1] was obtained. [Low molecular polyester 1] had a number average molecular weight of 2500, a weight average molecular weight of 6700, a peak molecular weight of 5000, a Tg of 43 ° C., and an acid value of 25.

~ Synthesis of intermediate polyester ~
Production Example 4
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction tube, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, 22 parts of trimellitic anhydride And 2 parts of dibutyltin oxide were added, reacted at 230 ° C. under normal pressure for 8 hours, and further reacted for 5 hours at a reduced pressure of 10 to 15 mmHg to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, Tg of 55 ° C., an acid value of 0.5, and a hydroxyl value of 51.
Next, 410 parts of [Intermediate Polyester 1], 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained. [Prepolymer 1] had a free isocyanate weight% of 1.53%.

~ Synthesis of ketimine ~
Production Example 5
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1]. The amine value of [ketimine compound 1] was 418.

~ Master batch synthesis ~
Production Example 6
Add 1200 parts water, 540 parts carbon black (made by Printex35 Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5], 1200 parts polyester resin, and mix with a Henschel mixer (Mitsui Mining Co., Ltd.). After kneading at 150 ° C. for 30 minutes using two rolls, rolling and cooling and pulverizing with a pulverizer, [Masterbatch 1] was obtained.

~ Preparation of oil phase ~
Production Example 7
In a container equipped with a stirring bar and a thermometer, 378 parts of [Low molecular polyester 1], 110 parts of carnauba wax, 32 parts of a charge control agent (metal salicylic acid zinc salt E-84: manufactured by Orient Chemical Industries), 947 parts of ethyl acetate Was heated to 80 ° C. with stirring, maintained at 80 ° C. for 5 hours, and then cooled to 30 ° C. in 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain [Raw material solution 1].
[Raw material solution 1] Transfer 1324 parts to a container and use a bead mill (manufactured by Ultra Visco Mill Imex Co., Ltd.) to fill a liquid feed rate of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 80% by volume of 0.5 mm zirconia beads. Carbon black and wax were dispersed under the condition of 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1]. The solid content concentration of [Pigment / WAX Dispersion 1] (130 ° C., 30 minutes) was 50%.

~ Emulsification, solvent removal ~
(Example 1)
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, and TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 1 minute After mixing, 1250 parts of [Aqueous Phase 1] was added to the container and mixed with a TK homomixer at a rotation speed of 12,500 rpm for 30 minutes to obtain [Emulsion Slurry 1].
[Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 40 ° C. for 5 hours, aging was carried out at 45 ° C. for 4 hours to obtain [Dispersion slurry 1].

~ Washing, drying ~
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(i) 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(ii) 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (i), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(iii) 100 parts of 10% hydrochloric acid was added to the filter cake of (ii), mixed with TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(iv) 300 parts of ion-exchanged water was added to the filter cake of (iii), mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered twice to obtain [filter cake 1]. .
[Filtration cake 1] was dried at 45 ° C. for 48 hours in a circulating drier, and sieved with an opening of 75 μm mesh to obtain [Toner 1]. This toner had a weight average particle diameter of 4.9 μm and an average circularity of 0.96.

~ Addition of external additives ~
Next, 100 parts of [Toner 1] was mixed with 0.7 part of hydrophobic silica using a Henschel mixer to complete the preparation of the toner.

(Example 2)
The solvent removal conditions of [Emulsified slurry 1] of Example 1 were changed to 35 hours at 7 hours to obtain [Dispersed slurry 2]. Except for this, [Toner 2] was obtained in the same manner as in Example 1.

(Comparative Example 1)
The solvent removal conditions for [Emulsion slurry 1] of Example 1 were changed to 40 hours at 2 hours to obtain [Dispersion slurry 3]. Except for this, [Comparative Toner 1] was obtained in the same manner as in Example 1.

(Comparative Example 2)
[Aqueous Phase 2] was produced in the same manner as in Production Example 2 except that the amount of [Fine Particle Dispersion 1] was changed from 99 parts to 60 parts by adjusting the aqueous phase in Production Example 2. Otherwise, the same as in Example 1. Thus, [Comparative Toner 2] was obtained.

(Comparative Example 3)
[Aqueous phase 3] was prepared in the same manner as in Example 1, except that the amount of [fine particle dispersion 1] was changed from 99 parts to 155 parts by adjusting the aqueous phase in Production Example 2. Otherwise, the same as in Example 1 Thus, [Comparative Toner 3] was obtained.

(Comparative Example 4)
Polyester resin (polyester resin synthesized from PO adduct of bisphenol A, terephthalic acid, trimellitic acid with a 1/2 outflow temperature of 135 ° C) 87 parts Masterbatch 1 16 parts Carnauba wax 5 parts Charge control agent (salicylic acid (Metal zinc salt E-84: Orient Chemical Co., Ltd.) After 2 parts were processed in the order of melt-kneading, pulverization, and classification with a uniaxial continuous kneader (BUSS kneader) to obtain toner base particles, the surface shown in FIG. Using a reformer, hot air at 300 ° C. was blown onto the toner base particles at a supply rate of 5 kg / h, and further rapidly cooled with cooling air at 2 ° C. Thereafter, the same hydrophobic silica as in Example 1 was externally added and mixed to obtain [Comparative Toner 4].

Table 1 shows the evaluation results of the toner obtained above.
In addition, using the above toner, the Ricoh imagio NEO 450 remodeling machine (variable charging pressure of the charging member, process speed 254 mm / sec) takes out the photoconductor for every 1,000 copies, and the cleaning part, charging The site was observed. The results are also shown in Table 1. Evaluation items and evaluation criteria are as follows.
1) Blade cleaning property ◯: A very small amount of toner passed through the cleaning blade.
Δ: A small amount of toner passed through the cleaning blade.
X: A large amount of toner passed through the cleaning blade.
2) Charging roller slip-through property ○: Almost all of the toner that passed through the cleaning blade passed through the charging roller.
Δ: The toner that passed through the cleaning blade sometimes failed to pass through the charging roller.
X: A small amount of toner passed through the cleaning blade accumulated at the contact portion between the charging roller and the photosensitive member.
3) Adhesiveness to charging roller: In the observation after 1,000 sheets were printed, the toner adhered to the charging roller but was not fused.
X: In the observation after printing 1,000 sheets, the toner adhered to the charging roller was fused.
4) Charging roller contamination rank 1: There is toner fusing over the entire surface.
3: The charging roller is contaminated, but no abnormal image based on charging failure or the like has occurred.
5: The charging roller is hardly contaminated.
Evaluation was made between ranks 1 to 5 using the above as a guide.

  Further, the evaluation results around the photoreceptors of the examples and comparative examples are summarized in Table 2. From Table 2, Examples 1 and 2 using the toner according to the present invention have good blade cleaning properties, and a small amount of toner passing through the cleaning blade does not contaminate the surface of the charging roller. It was found that formation can continue.

1 is a diagram showing a schematic configuration of an image forming apparatus for executing an image forming method of the present invention. FIG. 2 is a diagram showing a configuration around a photoconductor of the image forming apparatus shown in FIG. It is a figure which shows the structure of the charging device of a contact system. It is a figure which shows the structure of the charging device of a proximity system. It is a figure explaining the measuring method of the contact pressure of a charging roller. FIG. 3 is a diagram schematically illustrating a cross section of a toner according to the present invention. It is a figure which shows the structure of the surface modification processing apparatus of a toner particle.

Explanation of symbols

1 Photoconductor (image carrier)
2 Charging device 2a Charging roller 3 Exposure device 4 Developing device 6 Transfer device 7 Fixing device 8 Cleaning device 8a Cleaning blade

Claims (22)

A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier In an image forming method having a transfer step of transferring a toner image to a transfer target, and a cleaning step of cleaning the surface of the image carrier after the transfer step,
The process speed is 240 mm / sec or more,
The toner used in the development process is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) contains a release agent, almost all of the release agent is present inside the toner, and the release agent present on the toner surface imparts lubricity to the surface of the image carrier in the cleaning step;
(D) The release agent inside the toner oozes out on the toner surface in a state of being pressurized between the charging member and the image carrier or between the charging member and the member for cleaning the charging member. An image forming method characterized by not being leveraged. A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier In an image forming method having a transfer step of transferring a toner image to a transfer target, and a cleaning step of cleaning the surface of the image carrier after the transfer step,
The process speed is 240 mm / sec or more,
The toner used in the development process is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) An image forming method characterized in that it contains a release agent inside and the distance from the release agent particles to the toner surface is 0.01 to 1.5 μm on average. A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier In an image forming method having a transfer step of transferring a toner image to a transfer target, and a cleaning step of cleaning the surface of the image carrier after the transfer step,
The process speed is 240 mm / sec or more,
The toner used in the development process is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) An image forming method characterized in that it contains a release agent and has a dynamic friction coefficient of 0.18 to 0.45.   4. The image forming method according to claim 1, wherein the toner used in the developing step has an average circularity of 0.98 to 1.00. 5.   5. The image forming method according to claim 1, wherein the charging step includes setting the charging member and the image carrier to a gap of (2 × D4) to 70 μm between the surface of the charging member and the surface of the image carrier. An image forming method characterized by being performed in close proximity.   6. The image forming method according to claim 1, wherein the release agent contained in the toner is rice wax and / or ester wax.   The image forming method according to claim 1, wherein the release agent contained in the toner is dispersed in the toner with an average dispersion diameter of 0.3 to 1.0 μm. Image forming method.   The image forming method according to claim 1, wherein the toner is externally added with inorganic oxide fine particles that have been subjected to hydrophobic treatment.   9. The image forming method according to claim 1, wherein the toner is externally added with a lubricant.   The image forming method according to claim 1, wherein the toner contains a charge control agent made of a fluorine-containing compound.   11. The image forming method according to claim 1, wherein at least the polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent. An image forming method, wherein the toner material liquid is obtained by crosslinking and / or elongation reaction in an aqueous medium. An image carrier that carries an electrostatic latent image, a charging unit that uniformly charges the surface of the image carrier, and an exposure unit that exposes the surface of the charged image carrier based on image data and writes the electrostatic latent image A developing means for supplying toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, a transfer means for transferring the toner image on the surface of the image carrier to the transfer body, and a post-transfer In an image forming apparatus comprising a cleaning means for cleaning the surface of an image carrier,
The image forming apparatus executes the image forming method according to claim 1. A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier A toner used in an image forming method having a transfer step of transferring a toner image to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more,
The toner is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) contains a release agent, almost all of the release agent is present inside the toner, and the release agent present on the toner surface imparts lubricity to the surface of the image carrier in the cleaning step;
(D) The release agent inside the toner oozes out on the toner surface in a state of being pressurized between the charging member and the image carrier or between the charging member and the member for cleaning the charging member. Toner that does not come off. A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier A toner used in an image forming method having a transfer step of transferring a toner image to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more,
The toner is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) A toner containing a release agent inside and having an average distance from the release agent particles to the toner surface of 0.01 to 1.5 μm. A charging step in which a roller-shaped charging member is brought into contact with or close to the image carrier at a contact pressure of 0.23 N / cm or less, and a voltage is applied to the charging member to charge the surface of the image carrier, and the charged image carrier A latent image forming step for forming an electrostatic latent image on the surface, a developing step for supplying a toner to the electrostatic latent image formed on the surface of the image carrier to make it visible, and a surface formed on the surface of the image carrier A toner used in an image forming method having a transfer step of transferring a toner image to a transfer target and a cleaning step of cleaning the surface of the image carrier after the transfer step, and a process speed of 240 mm / sec or more,
The toner is
(A) The average circularity is 0.95 to 1.00,
(B) The weight average particle diameter (D4) is 2.5 to 6.5 μm,
(C) A toner containing a release agent inside and having a dynamic friction coefficient of 0.18 to 0.45.   The toner according to any one of claims 13 to 15, wherein the average circularity is 0.98 to 1.00.   The toner according to any one of claims 13 to 16, wherein the release agent is rice wax and / or ester wax.   18. The toner according to claim 13, wherein the release agent is dispersed in the toner with an average dispersion diameter of 0.3 to 1.0 μm.   The toner according to any one of claims 13 to 18, wherein the toner is externally added with hydrophobically treated inorganic oxide fine particles.   The toner according to claim 13, wherein the toner is formed by externally adding a lubricant.   21. The toner according to claim 13, wherein the toner contains a charge control agent comprising a fluorine-containing compound.   The toner according to any one of claims 13 to 21, wherein the toner is a toner in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or extending a material solution in an aqueous medium.

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