JP2018077385A - Image forming unit, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming unit that, even when using a toner containing an external additive component with a small diameter for improving image quality, satisfactorily prevents dirt on the surfaces of charging members and can form high-quality images for a long period.SOLUTION: An image forming unit comprises: an image carrier 1; charging means 2 that is in contact with the image carriers 1 to charge the surface of the image carrier 1; developing means 5 that forms a visible image by using toner; and charging cleaning means 10 that cleans the charging means 2. The toner includes base particles containing at least a binder resin and colorant and an external additive; the content of the external additive is 1 part by weight or more and 7 parts by weight or less based on 100 parts by weight of the base particles; the external additive includes at least one type of particles having an average number particle diameter of primary particles of 0.01 μm or more and 0.05 μm or less. The charging means 2 is a charging roller having an average interval (Rsm) between irregularities on its surface of 80 μm or less and an average height (Rc) of irregularities on its surface of 10 to 20 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming unit, an image forming apparatus, and an image forming method.

  In an image forming apparatus such as an electronic copying machine, a printer, or a facsimile, it is known that an electrostatic latent image is formed on an image carrier, and this is visualized with a developer to obtain a recorded image. A dry development method using a powdery developer is widely adopted.

  In recent years, color image forming apparatuses using an electrophotographic method have become widespread, and further high definition of printed images has been demanded due to the fact that digitized images can be easily obtained. ing. As the higher resolution and gradation of the image are studied, the improvement on the toner side that visualizes the electrostatic latent image is to further reduce the particle size and increase the charge to form a high-definition image. For this reason, studies have been made on small particle size external additives.

  On the other hand, in a cleaning process for cleaning the image carrier, as a generally used cleaning means, a blade member made of a plate-like urethane rubber or the like is brought into contact with the image carrier, and the toner that cannot be completely transferred, an external component Has been removed. However, if there are many small components of the external additive as described above, the external component attached to the surface of the image carrier cannot be completely removed by contact with the blade member, and the cleaning member passes through the charging member. There is a problem that is contaminated with external additives.

On the other hand, various means for cleaning the surface of the charging member have been studied. However, in the conventional means for cleaning the charging member, the amount of the external additive adhering to the charging member becomes non-uniform, and the resistance of the charging member surface fluctuates due to the difference in the amount of contamination. The potential changes, resulting in a problem of uneven density on the image.
Various techniques have been proposed for the above problems as follows.

In Patent Document 1, a voltage applied to the charging member and a voltage applied to the charging cleaning member are separately provided, an electric field is formed by a voltage difference applied to each, and the abrasive recovered by the charging cleaning member is electrically In addition, there has been proposed control for transferring to the surface of an image carrier.
However, while the means for electrically moving and collecting the external additive attached to the charging member is effective, it is difficult to collect the external additive present on the minute irregularities on the charging surface, resulting in unevenness on the charging member. In addition to remaining, the voltage supply means must be provided for each, and the apparatus is enlarged or the charging member cleaning control is separately provided, leading to a decrease in productivity.

Patent Document 2 proposes a means for keeping the charging member surface clean by defining the shape of the charging member surface and the length and thickness of the hair of the cleaning brush.
However, when cleaning with the brush member, a portion where the hair hits and a portion where the hair does not hit occurs on the surface of the charging member. there is a possibility.

Patent Document 3 proposes a configuration in which the charging member and the image carrier are provided with a minute gap, and silicon rubber is used for the cleaning member to keep the charging member clean.
However, it is difficult to maintain a minute gap with the image carrier over time, and an extremely expensive configuration such as an AC power source and a silicon roller must be taken, which is not feasible.

In Patent Document 4, the particle size and content of the toner external additive are set to desired values, and an elastic blade having a surface elastic modulus and a surface friction coefficient selected to the desired values is used as a cleaning means for the image carrier. Therefore, it has been proposed to suppress cleaning defects and obtain high-quality images.
However, in order to improve image quality, it is desired to improve the surface contamination of the charging member when using a toner containing a small-diameter external additive component, and to form a high-quality image over a long period of time. Yes.

  In the present invention, even when a toner containing a small-diameter external additive component is used to improve image quality, the surface contamination of the charging member is maintained in a good state, and a high-quality image can be formed over a long period of time. An object is to provide an image forming unit.

  In order to solve the above-described problems, the present invention provides an image carrier, a charging unit that contacts the image carrier and charges the surface of the image carrier, and a developing unit that forms a visible image using toner. And an electrostatic forming unit for cleaning the charging unit, wherein the toner includes base particles containing at least a binder resin and a colorant, and an external additive, and the external additive. The content of is not less than 1 part by weight and not more than 7 parts by weight with respect to 100 parts by weight of the base particles, and the external additive is a particle having an average number particle size of primary particles of 0.01 μm or more and 0.05 μm or less. And the charging means is a charging roller having an average interval (Rsm) of surface irregularities of 80 μm or less and an average height (Rc) of surface irregularities of 10 to 20 μm. To do.

  According to the present invention, even when a toner containing a small-diameter external additive component is used to improve image quality, the surface contamination of the charging member is maintained in a good state, and a high-quality image can be formed over a long period of time. It is possible to provide an image forming unit capable of

1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a schematic diagram showing an example of an image forming unit according to the present invention. It is sectional drawing for demonstrating an example of an electrostatic cleaning member. It is sectional drawing for demonstrating the other example of an electrostatic cleaning member. It is a perspective view for demonstrating an example of an electrostatic cleaning member. It is a perspective schematic diagram for demonstrating the other example of an electrostatic cleaning member. 3 is a result of a surface profile in the charging roller of Example 1. 6 is a result of a surface profile in the charging roller of Comparative Example 1.

  Hereinafter, an image forming unit, an image forming apparatus, and an image forming method according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

  The present invention includes an image carrier, a charging unit that contacts the image carrier and charges the surface of the image carrier, a developing unit that forms a visible image using toner, and a charging unit that cleans the charging unit. An image forming unit including a cleaning unit, wherein the toner includes base particles containing at least a binder resin and a colorant, and an external additive, and the content of the external additive is determined based on the base particles. 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight, and the external additive contains at least one kind of particles having an average number of primary particles of 0.01 μm or more and 0.05 μm or less. The means is a charging roller having an average interval (Rsm) of surface irregularities of 80 μm or less and an average height (Rc) of surface irregularities of 10 to 20 μm.

  The image forming method of the present invention includes a charging step for charging by a charging unit for charging the surface of the image carrier, a developing step for forming a visible image using toner, and a charging unit cleaning for cleaning the charging unit. An image forming method, wherein the developing step forms a visible image with toner containing at least a binder resin and a colorant and a external additive, and the external additive. The content of the agent is 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight of the base particles, and the external additive has an average primary particle number particle diameter of 0.01 μm or more and 0.05 μm. The charging step includes using at least one kind of the following particles, and the charging step uses a charging roller having an average interval (Rsm) of surface irregularities of 80 μm or less and an average height (Rc) of surface irregularities of 10 to 20 μm. Characterized by charging That.

  By using an external additive having a small particle diameter as described above, the fluidity of the toner can be improved, the chargeability of the toner is increased, and the charge amount distribution on the surface of the toner becomes uniform. The latent image can be developed faithfully, leading to higher image quality. On the other hand, for example, when a cleaning blade is used as a cleaning unit for the image carrier, the external additive component having a small particle diameter is not removed from the surface of the image carrier, and passes through the cleaning blade to externally add to the upstream charging unit. The agent may flow. This contaminates other members such as the charging roller.

On the other hand, according to the present embodiment, by selecting the unevenness of the surface of the charging roller so as to have the desired shape, the contact area between the surface of the photoreceptor and the surface of the charging roller, Resistance variation can be reduced. Further, by selecting the content of the external additive contained in the toner, the amount of the external additive adhering to the charging roller can be appropriately controlled, and the resistance fluctuation can be reduced.
As a result, even when a toner containing a small-diameter external additive component is used to improve the image quality, the surface contamination of the charging member can be kept good, and a high-quality image can be formed over a long period of time. Details will be described below.

  FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus according to the present embodiment. The embodiment of the image forming apparatus shown in FIG. 1 is an example of a so-called tandem type image forming apparatus. In FIG. 1, only black is represented, and the other colors are omitted.

  Around the drum-shaped photoreceptor 1 serving as an image carrier, there is a charging device 2 (charging means) for charging the drum surface, and a laser beam for forming a latent image on a uniformly charged surface. Exposure unit 3, a developing device 5 (developing unit) that forms a toner image by attaching charged toner to a latent image on the drum surface, and a toner image on the formed drum on a transfer target (recording medium, recording paper, etc.) A transfer device 7 for transferring the toner onto the drum, and a cleaning device 12 for removing residual toner on the drum.

  A toner replenishing container 4 for storing replaceable toner, connected to the developing device, and supplying the toner into the developing device is disposed above the developing device. Here, the toner supply container is configured to directly convey the toner into the developing container. However, the toner supply container may be configured to supply the toner to the developing container by providing a supply path in the main body of the image forming apparatus.

  In tandem type electrophotography, monochromatic images such as black, magenta, cyan and yellow are mainly formed on the surface of the photoreceptor. An area surrounded by a broken line constitutes an image forming unit corresponding to each color. In such a configuration, when image formation is performed by a negative positive method (lowering the exposure part potential and attaching the toner), the photoreceptor 1 whose surface is uniformly negatively charged by the charging roller of the charging device 2 is: An electrostatic latent image is formed on the surface of the photoconductor by exposure 3, and toner is attached to the surface of the photoconductor 1 by the developing device 5 to visualize the image.

  The toner image is transferred from the surface of the photoreceptor 1 by the transfer belt 13 and the transfer device 7, and residual toner components that have not been transferred from the photoreceptor 1 to the transfer belt 13 are removed from the surface of the photoreceptor by the cleaning blade 11 of the cleaning device 12. Removed.

  The toner image transferred to the surface of the transfer belt 13 is transferred to the recording paper conveyed from the paper feed tray by applying a bias to the secondary transfer roller 8 at the secondary transfer portion. The residual toner component or the external additive component after the transfer is removed by the cleaning unit 16.

  A cleaning unit 16 that cleans toner remaining on the surface of the transfer belt 13 includes a cleaning blade 14. The cleaning blade 14 is in contact with the moving direction of the transfer belt 13 so as to be a counter, and a metal cleaning facing roller 17 is provided so as to face the cleaning blade 14. The toner removed by the cleaning blade 14 is conveyed by the coil 18 and stored in the waste toner storage unit.

  Further, a sensor 15 is provided in the vicinity of the transfer belt 13 for measuring the amount of toner deposited on the transfer belt 13 and the position of each color and adjusting the image density and alignment. This is a combination of reflection and diffuse reflection.

  The toner image transferred to the recording paper is welded onto the recording paper by the fixing device 9 and is discharged from the paper discharge port.

  Next, the configuration around the photoreceptor in the image forming apparatus will be further described. FIG. 2 is a schematic enlarged view showing the configuration of the image forming unit according to the present embodiment.

  The toner container 31 is connected to the developing device 5 in this embodiment, and the inside of the toner replenishing container 4 is preferably constantly stirred by a stirring paddle 30 or the like in order to maintain toner fluidity. Screws or coils in the toner storage container 31 toward the developing device 5 or a toner replenishing port corresponding to a connecting portion with the toner replenishing path of the image forming apparatus (which will be described below in a configuration in which toner is directly replenished to the developing container). The toner can be transported by a transport means 32 such as the above. The conveying unit 32 is configured to be connectable to the main body driving unit, and the main body driving unit and the conveying unit can be controlled to be connected or disconnected by a known method such as a clutch, and the toner replenishment driving can be freely performed.

  The amount of toner replenishment can be controlled by the drive time of the drive unit. For example, control such as changing the drive time in response to the change in toner fluidity in a temperature and humidity environment is also possible.

  In the developing device, there is a partition plate 36 that is installed in the axial direction of the developing member 41 and that can divide the inside of the developing device. An opening is provided to allow movement.

  As described above, the toner replenished from the toner replenishing container into the developing device is transported in the axial direction of the developing member 41 by the first toner transporting member 37 constituted by a screw or the like installed in the upper tank. The transported toner is moved from the opening on the downstream side in the transport direction to the lower tank, and the second toner transport member 38 made of a screw or the like provided in the lower tank causes the first transport member 37 to move in the axial direction of the developing member. The toner can be conveyed in the opposite direction. On the downstream side of the second toner conveying member 38, the toner can move from the opening of the partition plate 36 to the upper tank, and the toner in the developing device can be circulated in the longitudinal direction. The toner conveyance speed can be controlled by the configuration of the conveyance member.

  The first and second toner conveying members are configured such that driving can be transmitted from a driving source installed in the main body of the image forming apparatus or the like by a driving transmission means including gears, couplings and the like. The toner in the developing unit can be moved to the developing member 41 by a toner supply member 40 formed of a sponge or the like that can supply the toner to the developing member 41.

  The toner moved to the developing member 41 by the supply member 40 is made uniform on the surface of the developing member 41 by the regulating member 42, and then an amount of toner corresponding to the surface potential of the photosensitive member 43 is transferred to the photosensitive member 43. It moves to the surface and is transferred to the transfer target by the transfer means. As described above, the toner that has moved to the photoconductor 43 and remains on the photoconductor as a transfer residue is removed by the cleaning unit 44 and then collected by installing a waste toner container in the image forming apparatus.

  An organic photoreceptor composed mainly of an organic material is used for the photoreceptor 43 which is an image carrier, and the surface is uniformly charged to a predetermined potential by the charging member 45 mainly by gap discharge. The charging member 45 may have a discharge product due to discharge, or an external additive attached to the surface of the photoconductor 43 that cannot be removed by the cleaning unit 44, and this causes resistance fluctuations. The electric potential cannot be uniformly charged. For this, it is known to dispose the charging cleaning member 46 and the like and clean the charging member 45.

  As a configuration for cleaning the charging member 45, it is known that a material mainly made of melamine resin, urethane resin, or the like is brought into contact with the charging member 45. A configuration in which the brush material is scraped off is known. Details will be described later.

  An exposure unit is provided between the charging member 45 and the developing member 41, and an electrostatic latent image can be formed on the photoconductor 43.

Next, the configuration of the charging member 45 will be described.
The charging member 45 of the present embodiment is a charging roller and is in contact with a photosensitive member 43 that is an image carrier. By applying a high voltage to the charging roller from a voltage supply device mainly composed of a DC power source, a discharge is caused in the minute section between the photosensitive member 43 and the charging roller generated at the contact portion, and the surface of the photosensitive member is made uniform. The structure is charged like this.

  In addition, a configuration is proposed in which the surface of the photoconductor 43 and the charging roller are not brought into contact with each other but a gap is formed minutely, and an AC voltage is applied from the power source, which is advantageous for charging roller contamination. However, there are disadvantages in that it is difficult to manage a minute gap for a long period of time, and the use of an AC power supply increases the cost and the size of the apparatus. The structure which contacts is preferable.

  The charging member 45 can be appropriately changed according to the purpose. For example, a surface of a solid roller using epichlorohydrin rubber is polished to have irregularities on the surface. In addition to this, for example, NBR (acrylonitrile-butadiene copolymer) can be used.

  As described above, the charging roller of the present embodiment is characterized in that the average interval (Rsm) of the surface irregularities is 80 μm or less, and the average height (Rc) of the surface irregularities is 10 to 20 μm.

When the Rsm exceeds 80 μm, the number of places where the charging roller and the photosensitive member are in contact with each other is reduced, resulting in uneven charging potential, and uneven density tends to occur. This causes image defects.
Rsm is preferably 30 μm or more. If it is smaller than 30 μm, it becomes difficult to process the charging roller.

  Further, when the Rc is less than 10 μm, when the external additive adheres to the concave portion on the surface of the charging roller, a portion where the attached external additive is in direct contact with the photosensitive member is generated, resulting in uneven charging potential. Therefore, uneven density tends to occur. When Rc exceeds 20 μm, the gap (gap) between the charging roller and the photosensitive member becomes large, so that the portion that does not come into contact with the photosensitive member increases, and a scumming phenomenon occurs in which the toner adheres to the uncharged portion due to defective discharge. .

  In addition, it is preferable that the uneven shape in the charging roller of the present embodiment has a longitudinal groove configuration in the circumferential direction of the charging roller.

  The surface shape of the charging roller is measured using a stylus type roughness measuring device, and in this embodiment, the surface shape is measured by SURFCOM 1400 manufactured by Tokyo Seimitsu Co., Ltd.

  The charging means for the charging roller can be appropriately changed, and examples thereof include polishing with a grindstone and polishing with a tape having roughness. Among these, polishing with a tape is preferable from the viewpoint of easily forming grooves uniformly in the circumferential direction. There is also a method of forming a surface shape by dispersing particles for forming irregularities in the vicinity of the roller surface, without using polishing.

  Further, the charging roller itself may be used in combination with a coating having a high water repellency such as fluorine, surface layer treatment such as impregnation, and surface modification by UV irradiation treatment to reduce the physical adhesion of the external additive itself. Thereby, the contamination of the charging roller surface can be improved.

Next, details of the charging cleaning member 46 will be described. The charging cleaning member 46 of this embodiment is in contact with the charging roller and keeps the surface of the charging roller (charging member 45) clean.
3 and 4 are schematic schematic views in a cross section perpendicular to the axial direction of the photosensitive member 43 and the charging roller. FIG. 3 shows an example in which the charging cleaning member 46 has a roller shape, and FIG. 4 shows an example in which the charging cleaning member 46 has a block shape.

  5 and 6 schematically show perspective views of examples of the photosensitive member 43, the charging roller (charging member 45), and the charging cleaning member 46. FIG. FIG. 5 shows an example in which the charging cleaning member 46 has a roller shape (sponge roller 46a), which corresponds to FIG. FIG. 6 shows an example in which the charging cleaning member 46 winds the sponge member 46b around the shaft body 46c.

  As described above, the shape of the charging cleaning member 46 can be appropriately changed according to the purpose. The shape of the roller as shown in FIGS. 3 and 5, the block shape as shown in FIG. The shape etc. which wound the sponge member as shown by the shaft body are mentioned. In addition to this, a sheet-like shape and the like are also included. Among them, the roller shape is preferable from the viewpoint of further suppressing charging contamination and extending the life because the contact surface is constantly updated.

  Note that “update” is a concept included in cleaning, but the roller and the roller are not always in contact with each other at the same location, but the roller and the roller are separated by, for example, providing a linear speed difference. It means that it touches at the point of, in other words, touches at a new point.

  Further, the example shown in FIG. 6 will be described in more detail. For example, a sponge block (sponge member 46b) may be wound on a spiral around a shaft body 46c such as a cored bar. In this case, the surface of the charging roller can be scraped off by the edge of the sponge block, which is preferable because the cleaning property of the surface of the charging roller is further improved.

The material used for the charging cleaning member 46 can be appropriately changed according to the purpose. For example, a foam material such as sponge, a resin material such as melamine, and the like can be used.
Of these, foam materials such as sponge are preferred. By using a foam material for the charge cleaning member 46, the convexity of the charging roller can be kept clean by sliding the charge cleaning member due to its flexibility. The external additive can be removed to such an extent that the adhering portion of the agent does not contact the image carrier. For this reason, the amount of external additive attached to the surface of the charging roller can be kept uniform over time, and image defects can be suppressed.

  The charging roller and the charging cleaning member are kept in contact with each other by a method such as fixing between the shafts, and are brought into contact with the surface of the photosensitive member by applying a load with a spring or the like, and are driven by the rotation of the photosensitive member. It can be set as the structure which each rotationally drives by rotation. In this case, a driving mechanism can be provided on the charging roller and the charging cleaning member separately, and the driving rotation can be performed. However, the driven rotation method is advantageous because the number of components is small and an inexpensive configuration can be obtained.

  Further, when the charging cleaning member has a roller shape (including a roller in which a sponge member is wound around a shaft body), the charging roller and the charging cleaning member may have the same speed (linear speed). It is preferable to set a linear velocity difference between the two. By applying the linear velocity difference, the rubbing force is improved, and the cleaning property of the charging member surface can be improved.

  The linear speed difference ratio can be appropriately changed according to the purpose, but it is preferable that the charging cleaning member rotates at a ratio of 1.0 to 1.1 with respect to the charging roller.

(toner)
The toner according to the exemplary embodiment includes at least base particles including a binder resin and a colorant, and an external additive, and includes other components such as a release agent, a charge control agent, and a plasticizer as necessary. May be. In the present embodiment, the colorant may be used as colored particles containing a colorant as an essential component.

<Binder resin>
Examples of the binder resin include polyester, polyurethane, polyurea, epoxy resin, vinyl resin, and the like. Alternatively, a hybrid resin in which different resins are chemically bonded may be used. Further, a reactive functional group may be introduced into the terminal or side chain of the resin and may be extended by being bonded in the toner production process. One of these can also be used alone. In the case of producing a toner having protrusions for controlling the surface shape, the resin constituting the colored particles is preferably different from the resin constituting the protrusions. Further, as the binder resin, it is also possible to use a resin used as a resin constituting the following colored particles.

<Resin constituting colored particles>
As the resin constituting the colored particles, a resin that is at least partially dissolved in an organic solvent is used, but the acid value is preferably 2 to 24 mgKOH / g. When the acid value exceeds 24 mgKOH / g, the transition to the aqueous phase is likely to occur, and as a result, loss in the material balance occurs during the production process, or the dispersion stability of the oil droplets deteriorates. Problems are likely to occur. Further, the moisture adsorption property of the toner is increased, and not only the charging ability is lowered, but also the storage property in a high temperature and high humidity environment is deteriorated. On the other hand, when the acid value is less than 2 mgKOH / g, the polarity of the resin becomes low, and it becomes difficult to uniformly disperse the colorant having a certain degree of polarity in the oil droplets.

  The type of resin is not particularly limited, but when used as an electrostatic latent image developing toner in electrophotography, it is preferable to use a resin having a polyester skeleton because good fixability can be obtained. Examples of the resin having a polyester skeleton include a polyester resin and a block polymer of a polyester and a resin having another skeleton, and the use of the polyester resin is preferable because the uniformity of colored particles obtained is high.

  Examples of the polyester resin include ring-opening polymers of lactones, polycondensation products of hydroxycarboxylic acids, polycondensates of polyols and polycarboxylic acids, and the like. Polycondensates are preferred.

  The peak molecular weight of the polyester resin is usually 1000 to 30000, preferably 1500 to 10000, and more preferably 2000 to 8000. If it is less than 1000, the heat-resistant storage stability deteriorates, and if it exceeds 30000, the low-temperature fixability of the electrostatic latent image developing toner deteriorates.

  The glass transition temperature of the polyester resin is 45 to 70 ° C, preferably 50 to 65 ° C. During transportation of the toner or toner cartridge, a high temperature and high humidity environment of 40 ° C. and 90% is assumed, and the obtained colored particles are deformed when placed under a certain pressure, or the colored particles adhere to each other. Less than 45 ° C. is not preferable because there is a possibility that the particles cannot behave. On the other hand, when the temperature exceeds 70 ° C., when the colored particles are used as a toner for developing an electrostatic latent image, the low-temperature fixability may be deteriorated.

<< Polyol >>
Examples of the polyol (1) include a diol (1-1) and a tri- or higher valent polyol (1-2), (1-1) alone or (1-1) and a small amount of (1-2). Mixtures are preferred.
Diol (1-1) includes 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; 3,3′- 4,4′-dihydroxybiphenyls such as difluoro-4,4′-dihydroxybiphenyl; bis (3-fluoro-4-hydroxyphenyl) methane, 1-phenyl-1,1-bis (3-fluoro-4- Hydroxyphenyl) ethane, 2,2-bis (3-fluoro-4-hydroxyphenyl) propane, 2,2-bis (3,5-difluoro-4-hydroxyphenyl) propane (also known as: tetrafluorobisphenol A), 2 , 2-bis (3-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane and other bis (hydroxyphenyl) alkanes; bis (3-fluoro-4-hydroxyphenyl) ether and the like Bis (4-hydroxyphenyl) ethers; alkylene oxides of the above bisphenols (ethylene oxide) , Propylene oxide, and the like butylene oxide, etc.) adducts.

  Among these, 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.

  Examples of the trivalent or higher polyol (1-2) include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

<< Polycarboxylic acid >>
Examples of polycarboxylic acid (2) include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). (2-1) alone or (2-1) and a small amount of ( The mixture of 2-2) is preferred.

  Dicarboxylic acid (2-1) includes alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid) , Naphthalenedicarboxylic acid, etc.), 3-fluoroisophthalic acid, 2-fluoroisophthalic acid, 2-fluoroterephthalic acid, 2,4,5,6-tetrafluoroisophthalic acid, 2,3,5,6-tetrafluoroterephthalic acid 5-trifluoromethylisophthalic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane, 2,2-bis (3-carboxyphenyl) hexafluoropropane, 2,2′-bis (trifluoromethyl) -4,4'-biphenyldicarboxylic acid, 3,3'-bis (trifluoromethyl Le) -4,4'-biphenyl dicarboxylic acid, 2,2'-bis (trifluoromethyl) -3,3'-biphenyl dicarboxylic acid, and the like hexafluoroisopropylidene diphthalic anhydride.

  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 polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). In addition, as polycarboxylic acid (2), you may make it react with polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.

  The ratio of the polyol and the polycarboxylic acid is usually 2/1 to 1/2, preferably 1.5 / 1 to 1/1 / as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 1.5, more preferably 1.3 / 1 to 1 / 1.3.

<< Modified resin >>
In addition, in order to increase the mechanical strength of the resulting colored particles or to prevent high temperature offset during fixing in addition to the previous mechanical strength when used as a toner for electrostatic latent image development, Colored particles may be obtained by dissolving a modified resin having an isocyanate group at the terminal.

  As a method for obtaining a modified resin, a method for obtaining a resin having an isocyanate group by polymerizing with an isocyanate-containing monomer, a method for obtaining a resin having an active hydrogen at the terminal, and then reacting with a polyisocyanate. Although the method of introduce | transducing an isocyanate group into a polymer terminal etc. is mentioned, The latter method can be preferably employ | adopted from the controllability of introducing an isocyanate group into a terminal.

  Examples of the active hydrogen include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are preferable.

  As the skeleton of the modified resin, in consideration of the uniformity of the particles, it is preferable to use the same resin as that dissolved in the organic solvent, and it is preferable to have a polyester skeleton.

  As a method for obtaining a resin having an alcoholic hydroxyl group at the end of the polyester, in the polycondensation of the polyol and the polycarboxylic acid, the polycondensation reaction may be carried out by making the number of functional groups of the polyol larger than the number of functional groups of the polycarboxylic acid. .

<< Amine compound >>
The isocyanate group of the modified resin is hydrolyzed in the process of dispersing the oil phase in the aqueous phase to obtain particles, and part of it becomes an amino group. The generated amino group reacts with the unreacted isocyanate group, and is elongated. The reaction proceeds. In addition to the above reaction, an amine compound can be used in combination for the purpose of reliably reacting the extension reaction or introducing a crosslinking point. As the amine compound (B), a diamine (B1), a trivalent or higher polyamine (B2), an amino alcohol (B3), an amino mercaptan (B4), an amino acid (B5), and an amino group blocked from B1 to B5 (B6) etc. are mentioned.

  Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, tetrafluoro-p-xylylenediamine, tetrafluoro-p-phenylenediamine, etc.); alicyclic diamines (4 , 4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, dodecafluorohexylenediamine, tetracosafluorododecylenediamine) Etc.).

  Examples of the trivalent or higher polyamine (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 B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines 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 such that the number of amino groups [NHx] in amines (B) is 4 times or less the number of isocyanate groups [NCO] in prepolymer (A) having an isocyanate group, preferably 2 It is not more than twice, more preferably not more than 1.5 times, and still more preferably not more than 1.2 times. If it exceeds 4 times, the excess amino group blocks the isocyanate and the extension reaction of the modified resin does not occur, so that the molecular weight of the polyester is lowered and the hot offset resistance may be deteriorated.

<Organic solvent>
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal of the solvent later. Examples of such organic solvents include 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.

  When the resin to be dissolved or dispersed in the organic solvent is a resin having a polyester skeleton, it is better to use an ester solvent such as methyl acetate, ethyl acetate or butyl acetate or a ketone solvent such as methyl ethyl ketone or methyl isobutyl ketone. High solubility is preferable. Of these, methyl acetate, ethyl acetate, and methyl ethyl ketone, which have high solvent removability, are particularly preferred.

<Aqueous medium>
As an aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolv (registered trademark)), lower ketones (eg, acetone, methyl ethyl ketone), and the like.

<Surfactant>
A surfactant is used to produce droplets by dispersing the oil phase in an aqueous medium.
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. It is. Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount.

  Examples of the anionic surfactant having a fluoroalkyl group preferably used include fluoroalkylcarboxylic 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) ) Carboxylic acid and metal salt, perfluoroalkyl carboxylic acid (C7 to C13) and its metal salt, perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, perfluorooctane sulfonic acid diethanolamide, N-propyl-N -(2-hydroxyethyl) par Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned. Further, as the cationic surfactant, aliphatic quaternary ammonium salts such as aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, and perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt and the like.

<Inorganic dispersant>
The dissolved or dispersed toner composition may be dispersed in the aqueous medium in the presence of an inorganic dispersant or resin fine particles. As the inorganic dispersant, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like are used. The use of a dispersant is preferable in that the particle size distribution becomes sharp and the dispersion is stable.

<Protective colloid>
Further, 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 Such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloroacrylate 2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N-methyl Tylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc., or esters of compounds containing vinyl alcohol and carboxyl groups, such as acetic acid Vinyl, 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 imidazole, ethyleneimine, etc. Homopolymers or copolymers such as those having a nitrogen atom or a heterocyclic ring thereof, polyoxyethylene, polyoxypropylene, polyoxyethylene Lenalkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester Polyoxyethylenes such as, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  In addition, when an acid such as calcium phosphate salt or an alkali-soluble one is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as washing with water after dissolving the calcium phosphate salt with an acid such as hydrochloric acid. To do. It can also be removed by operations such as enzymatic degradation. When a dispersant is used, the dispersant can remain on the surface of the toner particles. However, it is preferable from the charged surface of the toner that the dispersant is washed and removed after the elongation and / or crosslinking reaction.

<Colorant>
Known dyes and pigments can be used as the colorant, such as 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 rake, quinoline yellow rake, anthrazan yellow BGL, isoindolinone yellow, bengara, red lead, lead vermilion, cadmium red, cadmium mercurial red, antimon vermilion, permanent red 4R, para red, phissa red Parachlor ortho nitroani Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin 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, Thioindigo Red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, poly Zored, Chrome Vermilion, 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, Phtha Russia Nin green, anthraquinone green, titanium oxide, zinc white, lithopone, and mixtures thereof can be used.

<< Colorant masterbatch >>
The colorant used in the present embodiment can also be used as a master batch combined with a resin.
As the binder resin to be kneaded together with the production of the master batch or the master batch, in addition to the above-mentioned modified and unmodified polyester resins, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and polymers of substituted products thereof; Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α- Chloromethyl methacrylate copolymer, Len-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid Styrene copolymers such as acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, poly Acrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax and the like can be used alone or in combination. .

<< Master batch production method >>
As a method for producing a masterbatch, for example, a masterbatch can be obtained by mixing and kneading a resin for a masterbatch and a colorant under high shearing force. In this case, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. Also, a so-called flushing method called watering paste containing water of a colorant is mixed and kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

<External additive>
In the present embodiment, the content of the external additive is 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight of the base particles, and the external additive has an average primary particle number particle diameter of 0.01 μm or more and 0 parts by weight. Include at least one particle of 0.05 μm or less. The external additive may be inorganic fine particles or organic fine particles.

<< Inorganic fine particles >>
Examples of inorganic fine particles used as external additives in the present embodiment include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, List silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. Can do. Among these, silica and titanium oxide are particularly preferable, and silica is more preferable from the viewpoint of adhesion to a member.

<< Organic fine particles >>
Examples of the organic fine particles used as an external additive in the present embodiment include polymers of styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, and substituted polymers thereof; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer. Polymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-acrylic acid Octyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer , Styrene-vinyl methyl ketone copolymer Styrene copolymers such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; 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, aliphatic or Examples thereof include alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins and paraffin waxes, and these can be used alone or in combination.

<< Hydrophobic treatment >>
The external additive used in this embodiment preferably has a hydrophobic surface. For example, as a method for hydrophobizing inorganic fine particles, a method of chemically treating with an organic silicon compound that reacts or physically adsorbs with inorganic fine particles is used. A preferred method is a method of treating inorganic fine particles produced by vapor phase oxidation of a metal halide compound with an organosilicon compound.

  Examples of organosilicon compounds used in the hydrophobization treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methotrechlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyl Dimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxy Silane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Rudisiloxane, 1,3-diphenyltetramethyldisiloxane, dimethylpolysiloxane containing 2 to 12 siloxane units per molecule and having hydroxyl groups bonded to Si each addressed to a terminal unit is there.

  A nitrogen-containing silane coupling agent can be used for hydrophobizing untreated inorganic fine particles. Here, the case where the charging polarity of the toner base particles shows negative polarity will be described in particular, but in the case of using an external additive having a reverse polarity charging property, fine particles which are surface-treated with a nitrogen-containing silane coupling agent are preferred. .

  Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, Monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ -Propylbenzamine, Trimethoxysilyl-γ-propylpiperidine, Trimethoxysilyl-γ-propylmorpholine, Tri There are Tokishishiriru -γ- propyl imidazole. These treatment agents are used alone or in a mixture of two or more.

  In the present embodiment, an inorganic fine particle that has been hydrophobized or not hydrophobized and that has been treated with silicone oil may be used. Silicone oils in this case include dimethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, amino acid Modified silicone oil, epoxy-modified silicone oil, epoxy-polyether-modified silicone oil, phenol-modified silicone oil, carboxyl-modified silicone oil, mercapto-modified silicone oil, acrylic, methacryl-modified silicone oil, α-methylstyrene-modified silicone oil, and the like can be used.

  These silicone oils are used alone or in a mixture of two or more. In order to treat the inorganic fine particles with silicone oil, the inorganic fine particles that have been sufficiently dehydrated and dried in advance in an oven of several hundred degrees Celsius are uniformly contacted with the silicone oil to adhere the silicone oil to the surface of the inorganic fine particles.

  In order to attach the silicone oil, the inorganic fine particle powder and the silicone oil are sufficiently mixed with the powder by a mixer such as a rotary blade, or the silicone oil is dissolved with a relatively low boiling point solvent capable of diluting the silicone oil, What is necessary is just to impregnate the inorganic fine particle powder in the liquid and remove the solvent and dry it.

  When the viscosity of the silicone oil is high, the treatment is preferably performed in a liquid. After that, the inorganic fine particle powder to which the silicone oil is adhered is subjected to heat treatment in an oven at 100 ° C. to several hundred degrees (usually around 400 ° C.), thereby using the hydroxyl group on the surface of the inorganic fine particle powder to form a siloxane bond between the metal and the silicone oil. The silicone oil itself can be further polymerized and crosslinked.

  A catalyst such as acid, alkali, metal salt, zinc octylate, tin octylate, dibutyltin dilaurate or the like may be included in the silicone oil in advance to promote the reaction. By transferring the silicone oil to the electrostatic latent image carrier, the frictional force with the cleaning blade can be reduced over a long period of time, and wear can be significantly suppressed.

  The inorganic fine particles used in the present embodiment may be previously treated with a hydrophobizing agent of a silane coupling agent before the silicone oil treatment. Inorganic powder that has been hydrophobized in advance increases the amount of silicone oil adsorbed.

<< Particle size of external additive >>
Two or more external additives may be used in the present embodiment. At least one kind of particles having an average number particle size (Dn) of primary particles of 0.01 μm or more and 0.05 μm or less is selected. By using such an external additive having a small particle diameter, the fluidity of the toner can be improved, the chargeability of the toner is increased, and the charge amount distribution on the surface of the toner becomes uniform. The latent image can be developed at the same time, leading to higher image quality.

  The average number particle size of the primary particles is preferably 0.01 μm or more and 0.02 μm or less. In this case, the embedding in the base particles can be within a desired range, and the desired fluidity can be obtained.

  In addition, in the external additive having an average number particle diameter satisfying the above range, when a large particle size and a small particle size are mixed, the large particle size acts as a spacer for suppressing contact between the toner and the member, and the particle size A toner having a small value is considered to give fluidity to the toner. The larger the particle size of the external additive, the more easily it is released from the toner, and the transition to the electrostatic latent image carrier is promoted. However, since the contamination of the member occurs, it is necessary to select the particle size in consideration of the balance. There is.

  As described above, when an external additive having an average particle diameter in the above range is used, improvement in toner fluidity and image quality can be expected. However, for example, when a cleaning blade is used as the image carrier cleaning means, the above range is satisfied. The external additive having an average particle diameter causes contamination of the member. This contamination occurs when the external additive component having a small particle diameter passes through the cleaning blade without being removed from the surface of the image carrier and flows to the upstream charging means. In the case of the contact charging method, since the charging roller is brought into contact with the image carrier, the external additive or the like adheres physically or electrically. As a result, the variation in charging is increased, charging unevenness occurs, and image unevenness occurs.

  In contrast to this, as in the image forming apparatus of the present embodiment described above, the contact area between the photosensitive member surface and the charging roller surface is selected by strictly selecting the unevenness of the charging roller surface to a desired shape. The resistance fluctuation on the contact surface of the photoreceptor can be reduced. In addition to this, by strictly selecting the content of the external additive as described below, the amount of the external additive adhering to the charging roller can be appropriately controlled, and resistance fluctuation can be reduced. Can do. For this reason, even when a toner containing a small-diameter external additive component is used to improve the image quality, the surface contamination of the charging member can be kept good, and a high-quality image can be formed over a long period of time.

  The particle diameter of the external additive used in the present embodiment can be measured by a particle size distribution measuring apparatus using dynamic light scattering, for example, DLS-700 manufactured by Otsuka Electronics Co., Ltd. or Coulter N4 manufactured by Coulter Electronics. is there. However, since it is difficult to dissociate the aggregation of external additives, it is preferable to directly determine the particle diameter from a toner image obtained by a scanning electron microscope or a transmission electron microscope. In this case, at least 10 or more, preferably 100 or more external additives are observed, and the average value of the major axis is obtained. Even when the external additive has an aggregated structure on the toner surface, the major axis of the single primary particle constituting the aggregate is determined.

<< Content of external additive >>
In the toner according to the exemplary embodiment, the characteristics as the toner can be controlled by the amount of the external additive. In this embodiment, the content of the external additive is 4.0 parts by weight or more and 7.0 parts by weight or less with respect to 100 parts by weight of the base particles. If the amount is less than 4.0 parts by weight, the formation of the deposited layer becomes insufficient, which is not preferable. Exceeding 7.0 parts by weight is not preferable because the amount of the external additive to be liberated becomes excessive, and problems such as member contamination are liable to occur and the low-temperature fixability is lowered.

The content of the external additive is preferably 4.0 parts by weight or more and 5.5 parts by weight or less.
When using 2 or more types as an external additive, those total should just be in the said range.

<< Quantification of external additives >>
To determine the amount of the external additive in the toner, first, 2 g of the measurement toner is collected, and a force of 1 N / cm ² is applied for 60 seconds to produce a circular toner pellet. The pellets are quantified by using a wavelength dispersive X-ray fluorescence analyzer XRF1700 manufactured by Shimadzu Corporation, and the elements inherent to the external additive (eg, Si, Ti, etc.) are quantified, and the external additive present in the toner is determined by a calibration curve method. It is calculated by weight% as an agent composition amount (for example, metal oxide fine particle amount: SiO ₂ , TiO ₂ amount). That is, using a fluorescent X-ray analyzer, the amount is determined by a calibration curve method based on the element specific to the external additive of the toner (for example, silicon in the case of silica), and the external additive composition amount (% by weight) is calculated. .

<< Polarity of external additive >>
In the external additive of the present embodiment, the polarity of particles having an average number particle size of the primary particles of 0.01 μm or more and 0.05 μm or less is preferably opposite to that of the base particle. Generally, whether the toner has a positive charge or a negative charge often depends on the charge of the external additive. Therefore, when only the particles having an average number particle diameter of the primary particles of 0.01 μm or more and 0.05 μm or less are used as external additives, it is preferable to use those having a polarity opposite to the polarity of the base particles. When other external additives are used as the additive in addition to the particles having an average number of primary particles of 0.01 μm or more and 0.05 μm or less, those having a polarity opposite to that of the other external additives are used. It is preferable to use it.

  By adding an additive material having a reverse polarity, the chargeability of the toner can be improved by the pseudo carrier effect, and the amount of background contamination can be reduced. In addition, since the adhesion to the charging roller is increased, the surface contamination of the charging member can be maintained in a better state even when using a toner containing a small-diameter external additive component for high image quality. A high-quality image can be formed over a long period of time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example. In the following, “part” represents “part by weight” and “%” represents “% by weight”.

(toner)
First, preparation of the toner used in Example 1 will be described. The toner used in Example 1 was prepared as follows.

<Method for producing resin dispersion 1>
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 0.7 part of sodium dodecyl sulfate and 498 parts of ion-exchanged water were added and dissolved by heating to 80 ° C. with stirring, and then potassium persulfate. A solution obtained by dissolving 2.6 parts in 104 parts of ion-exchanged water was added, and 15 minutes later, a monomer mixture of 170 parts of styrene monomer, 30 parts of butyl acrylate, and 8.2 parts of n-octanethiol was added for 90 minutes. The mixture was added dropwise, and then kept at 80 ° C. for 60 minutes to cause a polymerization reaction.
Then, it cooled and white [resin dispersion 1] with a volume average particle diameter of 53.2 nm was obtained. The obtained [Resin Dispersion 1] was placed in a 2 ml petri dish and the dried solid obtained by evaporating the dispersion medium was measured. The number average molecular weight was 5400, the weight average molecular weight was 9800, and the Tg was 49.4 ° C. Met.

<Synthesis of polyester 1>
229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propion oxide 3-mole adduct, 208 parts of terephthalic acid, 46 parts of adipic acid and dibutyltin oxide 2 parts were added and reacted at 230 ° C. under normal pressure for 8 hours. Next, after reacting under reduced pressure of 10 to 15 mmHg for 5 hours, 44 parts of trimellitic anhydride was added to the reaction vessel and reacted at 180 ° C. for 2 hours under normal pressure to synthesize [Polyester 1]. . The obtained [Polyester 1] had a number average molecular weight of 2,500, a weight average molecular weight of 6,700, a glass transition temperature of 43 ° C., and an acid value of 25 mgKOH / g.

<Synthesis of polyester 2>
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 264 parts of bisphenol A ethylene oxide 2-mole adduct, 523 parts of bisphenol A propylene oxide 2-mole adduct, 123 parts of terephthalic acid, 173 parts of adipic acid and dibutyl 1 part of tin oxide was added and reacted for 8 hours at 230 ° C. under normal pressure, and further reacted for 8 hours under reduced pressure of 10 to 15 mmHg. Thereafter, 26 parts of trimellitic anhydride was added to the reaction vessel and reacted at 180 ° C. and normal pressure for 2 hours to obtain [Polyester 2]. [Polyester 2] had a number average molecular weight of 4000, a weight average molecular weight of 47000, Tg of 65 ° C., and an acid value of 12.

<Synthesis of Isocyanate-Modified Polyester 1>
In a reaction vessel equipped with a cooling tube, 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 and reacted at 230 ° C. for 8 hours under normal pressure. Next, it was reacted for 5 hours under a reduced pressure of 10 to 15 mmHg to synthesize [Intermediate Polyester 1]. The obtained [Intermediate polyester 1] has a number average molecular weight of 2,200, a weight average molecular weight of 9,700, a glass transition temperature of 54 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 52 mgKOH / g. there were.
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. Modified polyester 1] was obtained.

<Preparation of master batch>
40 parts of carbon black (Regal 400R manufactured by Cabot Corporation), polyester resin (Sanyo Kasei RS-801, acid value 10, Mw 20,000, Tg 64 ° C.) 60 parts as binder resin, and 30 parts of water are mixed in a Henschel mixer. A mixture in which water was soaked into the pigment aggregate was obtained. This was kneaded for 45 minutes with two rolls set at a roll surface temperature of 130 ° C. and pulverized to a size of 1 mm with a pulverizer to obtain [Masterbatch 1].

<Oil phase preparation process>
In a container equipped with a stirrer and a thermometer, 545 parts of [Polyester 1], 181 parts of paraffin wax (melting point 74 ° C.), and 1450 parts of ethyl acetate are charged. After holding, it was cooled to 30 ° C. in 1 hour. Next, 500 parts of [Masterbatch 1] and 100 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain [Raw material solution 1].
[Raw material solution 1] 1500 parts are transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), a liquid feed speed of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 0.5 mm zirconia beads are 80% by volume. The pigment and WAX were dispersed under the conditions of filling and 3 passes. Next, 655 parts of a 66% ethyl acetate solution of [Polyester 2] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1].
[Pigment / WAX Dispersion 1] 976 parts were mixed for 1 minute at 5,000 rpm with a TK homomixer (made by Tokushu Kika), and then 88 parts of [Isocyanate-modified polyester 1] were added to a TK Homomixer (made by Tokushu Kika). ) At 5,000 rpm for 1 minute to obtain [Oil Phase 1]. The solid content of [Oil Phase 1] obtained was measured to be 52.0% by weight, and the amount of ethyl acetate based on the solid content was 92% by weight.

<Preparation of aqueous phase>
970 parts of ion-exchange water, 40 parts of a 25 wt% aqueous dispersion of organic resin fine particles (styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt copolymer) for dispersion stabilization, dodecyl diphenyl ether When 95 parts of a 48.5% aqueous solution of sodium disulfonate and 98 parts of ethyl acetate were mixed and stirred, the pH reached 6.2. A 10% aqueous sodium hydroxide solution was added dropwise thereto to adjust the pH to 9.5 to obtain [Aqueous Phase 1].

<Core particle production process>
Add 1200 parts of [Aqueous Phase 1] to the obtained [Oil Phase 1], and cool in a water bath to suppress the temperature rise due to shear heat of the mixer so that the temperature in the liquid is in the range of 20-23 ° C. , Adjusted at a speed of 8,000-15,000 rpm using a TK homomixer and mixed for 2 minutes, then adjusted at a speed of 130-350 rpm with a three-one motor with an anchor blade attached for 10 minutes The mixture was stirred to obtain [core particle slurry 1] in which droplets of an oil phase serving as core particles were dispersed in an aqueous phase.

<Formation of protrusions>
Ion exchange with 106 parts of [Resin dispersion 1] at a liquid temperature of 22 ° C. while stirring the [core particle slurry 1] with a three-one motor with an anchor blade attached at a rotation speed of 130 to 350 rpm. A mixture of 71 parts of water (solid content concentration 15%) was added dropwise over 3 minutes. After dropping, the number of rotations was adjusted to 200 to 450 rpm, and stirring was continued for 30 minutes to obtain [Composite Particle Slurry 1]. When 1 ml of [Composite Particle Slurry 1] was taken and diluted to 10 ml and centrifuged, the supernatant was transparent.

<Desolvent>
[Composite particle slurry 1] was charged into a container equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 8 hours while stirring to obtain [Dispersion slurry 1]. When [Dispersion Slurry 1] was placed on a small amount of slide glass and observed with an optical microscope at a magnification of 200 times with a cover glass in between, uniform colored particles were observed. Further, when 1 ml of [Dispersion Slurry 1] was taken and diluted to 10 ml and centrifuged, the supernatant was transparent.

<Washing and drying process>
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1): 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.
(2): 900 parts of ion-exchanged water was added to the filter cake of (1), ultrasonic vibration was applied, and the mixture was mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. This operation was repeated so that the electric conductivity of the reslurry liquid was 10 μC / cm or less.
(3): 10% hydrochloric acid was added so that the reslurry solution of (2) had a pH of 4, and the mixture was directly filtered with a three-one motor for 30 minutes.
(4): 100 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (10 minutes at 12,000 rpm) and then filtered. This operation was repeated so that the reslurry liquid had an electric conductivity of 10 μC / cm or less 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 Base 1]. The obtained [Toner Base 1] was observed with a scanning electron microscope. As a result, vinyl resin uniformly adhered to the surface of the core particles.

  Silica (RX200 manufactured by Nippon Aerosil Co., Ltd., average number particle diameter of primary particles: 0.02 μm) is added to [Toner Base 1] and mixed for 10 minutes with a Henschel mixer, and a sieve having an opening of 60 μm is added. By removing coarse particles and aggregates by passing, [Toner 1] was obtained. The external additive was added so that the external additive was 4.5 parts by weight with respect to 100 parts by weight of [Toner Base 1].

Example 1
The charging roller is brought into contact with the photosensitive member by spring bias, and the charging roller is driven by driven rotation.
As the charging roller, an epichlorohydrin rubber material was prepared, and the surface was polished with a tape to form irregularities on the surface of the charging roller. When the surface shape of the obtained charging roller was measured using a stylus type roughness measuring device (SURFCOM 1400 manufactured by Tokyo Seimitsu Co., Ltd.), Rsm = 62.74 μm and Rc = 10.84 μm. FIG. 7 shows the surface profile of the obtained charging roller.

  As shown in FIG. 4, the charging cleaning member has a configuration in which a urethane sponge block is abutted against the charging roller to clean the surface of the charging roller.

  The following evaluation was performed using the toner and the charging roller obtained above. Evaluation was performed using the black toner using an apparatus as shown in FIGS. 1 and 2. The results are shown in Table 1.

(Example 2)
In Example 1, as an external additive for toner, an average number particle size of primary particles is 0.02 μm, and a positively-charged material (silica, H30TA manufactured by Clariant Japan Co., Ltd.) opposite to [Toner Base 1] is used. Evaluation was carried out in the same manner as in Example 1 except that the change was made.

(Example 3)
In the first embodiment, as shown in FIGS. 3 and 5, the first embodiment is the same as the first embodiment except that a urethane sponge roller is used, and the charging roller is in contact with the shaft fixedly between the shafts and driven to rotate. Evaluation was performed in the same manner as above.

Example 4
In Example 1, as shown in FIG. 6, the charging cleaning member is a roller in which a sponge sponge made of urethane is spirally wound around a core metal, and is brought into contact with the charging roller by fixing between the shafts and driven to rotate. Evaluation was carried out in the same manner as in Example 1 except that.

(Example 5)
In the first embodiment, as shown in FIGS. 3 and 5, the charging cleaning member is a urethane sponge roller, which is brought into contact with the charging roller and connected with gears having different gear ratios. Evaluation was performed in the same manner as in Example 1 except that the linear speed ratio was changed to 1.09.

(Comparative Example 1)
In Example 1, the charging roller polishing method was changed to change the uneven shape on the surface of the charging roller. When the surface shape of the obtained charging roller was measured with a stylus type roughness measuring device (SURFCOM 1400, manufactured by Tokyo Seimitsu Co., Ltd.), Rsm was 124.7 μm and Rc was 6.9 μm. FIG. 8 shows the surface profile of the obtained charging roller. Except for this, the evaluation was performed in the same manner as in Example 1.

(Comparative Example 2)
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the charging cleaning member was not used.

(Comparative Example 3)
In Example 1, the evaluation was performed in the same manner as in Example 1 except that a component having an average number of primary particles of 0.02 μm was not used as an external additive for the toner.

(Evaluation)
The evaluation was performed by assembling the charging roller and the charging cleaning member obtained above in an image forming unit of an Ipsio SPC730 manufactured by Ricoh Co., Ltd., and performing a paper passing test using the toner obtained above.

  As the paper passing image, one having an image area ratio of 0.5% and 25% was used, and continuous output of 2000 sheets each was one set. That is, one set of 4000 sheets is output. As an environment, 2 sets were performed at 27 ° C. and 80%, and then 4 sets were performed at 10 ° C. and 15%. The transfer rate was set to 70% in order to increase the input amount to the cleaning means.

<Image rank evaluation>
In the image rank evaluation, density unevenness due to charging roller contamination was evaluated by ranking the stripes on the halftone image according to the following criteria. The rank was evaluated every time one set was performed. Rank 4 or higher is an acceptable level.

[Image rank evaluation criteria]
Rank 5: No streaks Rank 4: Slight streaks, but acceptable level Rank 3: Generation of weak streaks on the image plane Rank 2: Generation of streaks on the image plane Rank 1: Generation of streaks over the margin

<Soil dirt>
For background smudges, the main body is forcibly stopped during A4 white image passing when paper passing at 27 ° C. and 80% is completed (at the end of two sets), and a transparent tape is pasted on the photosensitive member. Dirty toner was collected. This is pasted on a white paper (type 6000 manufactured by Ricoh Co., Ltd.), the brightness is measured with a color difference meter (X-rite) from there, and the amount of background toner on the photoconductor is digitized. Evaluation was performed.

  The smaller the amount of background toner, the smaller the amount of toner used other than image formation, and the better the consumption efficiency. The lightness (L *) increases as the background toner amount decreases, and if the system has L * of 89 or more, a sufficient amount of toner is provided to satisfy the service life, which is an acceptable criterion.

  Table 1 shows the configurations of Examples and Comparative Examples and the results obtained. The content (% by weight) of the external additive indicates the ratio of the external additive to the base particles.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure 4 Toner supply container 5 Developing device 7 Transfer device 9 Fixing device 10 Charging member cleaning means 11 Cleaning blade 12 Cleaning device 13 Transfer belt 14 Cleaning blade 15 Sensor 16 Transfer belt cleaning device 17 Cleaning counter roller 18 Recovery roller 30 Stirring paddle 31 Toner container 32 Conveying means 36 Partition plate 37 First toner conveying member 38 Second toner conveying member 40 Supply member 41 Developing member 42 Restricting member 43 Photoconductor 44 Cleaning means 45 Charging member 46 Charge cleaning Member 46a Sponge roller 46b Sponge member 46c Shaft body

Japanese Patent No. 5473588 Japanese Patent No. 4834383 JP 2007-94315 A JP 2016-33612 A

Claims (8)

An image carrier, a charging unit that contacts the image carrier and charges the surface of the image carrier, a developing unit that forms a visible image using toner, a charging cleaning unit that cleans the charging unit, An image forming unit comprising:
The toner includes base particles containing at least a binder resin and a colorant, and an external additive,
The content of the external additive is 1 part by weight or more and 7 parts by weight or less with respect to 100 parts by weight of the base particles,
The external additive includes at least one kind of particles having an average number of primary particles of 0.01 μm or more and 0.05 μm or less,
The image forming unit, wherein the charging unit is a charging roller having an average interval (Rsm) of surface irregularities of 80 μm or less and an average height (Rc) of surface irregularities of 10 to 20 μm.   2. The image forming unit according to claim 1, wherein the polarity of particles having an average number of primary particles of 0.01 μm or more and 0.05 μm or less is opposite to that of the base particles.   The image forming unit according to claim 1, wherein the charging cleaning unit is made of a foam member and is in contact with the charging unit.   The image forming unit according to claim 1, wherein the charging cleaning unit is a sponge roller.   The image forming unit according to claim 1, wherein the charging cleaning unit is formed by spirally winding a sponge member around a shaft body.   An image forming apparatus comprising the image forming unit according to claim 1. An image forming method comprising: a charging step for charging by a charging unit for charging the surface of an image carrier; a developing step for forming a visible image using toner; and a charging unit cleaning step for cleaning the charging unit. And
The developing step forms a visible image with a toner containing at least a base resin containing a binder resin and a colorant and an external additive, and the content of the external additive is 100 parts by weight of the base particle. 1 part by weight or more and 7 parts by weight or less, and the external additive contains at least one kind of particles having an average number of primary particles of 0.01 μm or more and 0.05 μm or less,
In the charging step, charging is performed using a charging roller having an average interval (Rsm) of surface irregularities of 80 μm or less and an average height (Rc) of surface irregularities of 10 to 20 μm. Method. The charging means cleaning step is performed by a sponge roller or a roller in which a sponge member is spirally wound around a shaft body,
The image forming method according to claim 7, wherein the charging roller has a linear velocity difference from the sponge roller or a roller in which a sponge member is spirally wound around a shaft body.

Images