JP4346075B2 - Image forming apparatus and toner used therefor - Google Patents

Description

  The present invention relates to an image forming apparatus and a process cartridge used for image formation by an electrostatic copying process such as a copying machine, a facsimile machine, and a printer, and to a toner used for the image forming apparatus and the like.

In recent years, image forming apparatuses such as copying machines and printers are desired to be miniaturized and high-definition images for full-color images. In particular, since a color image forms an image by superimposing a plurality of toners, changes over time in toner developability, transferability, and fixability are greatly affected.
Further, for high-definition images, a toner having a small particle diameter is used regardless of the pulverization toner and the polymerization system. The toner having a small particle size has a problem such that the fluidity of the toner is lowered, the mixing property with the carrier is lowered, the toner is unevenly distributed, and the toner charge amount distribution is widened. To the toner, external additives such as inorganic fine particles are added as a fluidity imparting agent in order to supplement the fluidity corresponding to the increase in the surface area per unit weight as the particle size becomes smaller. Since the toner adhesion amount is relatively increased by reducing the particle size, it is necessary to add an external additive more than the surface area. For this reason, the amount of external additives on the toner surface increases, so that the cleaning blade is polished to shorten the service life or the inorganic fine particles having a large heat capacity prevent the contact with the fixing roller and the heating roller in the fixing device. Therefore, there is a problem that the fixing property is lowered.

  On the other hand, spherical toner is often used for high-definition images. Although the spherical toner has high fluidity, the blade cleaning method in an actual image forming apparatus has a problem that it passes under the blade to cause a cleaning failure.

Therefore, for example, in Patent Document 1, in a toner composed of at least a binder resin, a colorant, and an additive, the additive is composed of a dry process silica and a wet process silica, and the dry process silica has a hydrophobicity of 60 to 90. % And an average particle size of 0.05 to 5 μm and no coarse particles having a particle size of 10 μm or more, and the wet-process silica has a hydrophobization rate of 50 to 60% and an average particle size of 0.1%. An electrostatic latent image developing toner having a particle size of 05 to 5 μm and containing no coarse particles having a particle diameter of 10 μm or more is disclosed.
In Patent Document 2, toner mother particles containing at least a binder resin and a colorant, an average primary particle diameter of 80 to 300 nm whose surface has been subjected to a hydrophobic treatment, a water content of 3 to 15%, and a volume resistivity of 1 are used. × 10 ¹³ toner for developing electrostatic images which comprises a sol-gel method silica is Ωcm or more is disclosed.
Further, in Patent Document 3, an electrophotographic photosensitive member used for repeated image formation and a plurality of developing units loaded with color toners each having an average circularity of 0.95 to 0.99 are used. In an image forming apparatus that forms an image and uses an elastic rubber blade to clean the photoreceptor, the toner of at least one color has a silica-based particle as an external additive and a weight average particle diameter (D50). An image forming apparatus to which inorganic fine particles of 100 to 1000 nm are added is disclosed.
Patent Document 4 discloses a toner composition containing sol-gel metal oxide particles surface-treated with a binder, a colorant, and a treating agent.

In recent years, color image forming apparatuses are provided with a plurality of image carriers corresponding to high speed and high image quality, and color images are formed by superimposing toner images of respective colors on an intermediate transfer member, The color image is often transferred to a recording medium and fixed at a time. If the process of transferring from the image carrier to the intermediate transfer member is the primary transfer, and the process of transferring from the intermediate transfer member to the recording medium is the secondary transfer, the transfer is repeated twice, and the image is transferred to the intermediate transfer member and the recording medium. The state of the external additive on the toner surface changes every time.
For example, in Patent Document 5, in an image forming apparatus in which a toner image on a latent image carrier obtained by developing with a one-component nonmagnetic toner is intermediately transferred to an intermediate transfer medium, the external additive is One-component non-magnetic toner having at least a hydrophobic rutile-anatase type titanium oxide having a spindle shape and having a work function larger than that of the toner base particles or substantially the same as that of the toner base particles An image forming apparatus using the above is disclosed.

JP-A-4-080764 JP 2002-108001 A JP 2003-215836 A JP 2003-215837 A JP 2003-107785 A

However, the techniques disclosed in Patent Documents 1 to 4 improve the transfer rate by using an external additive having a large particle size, prevent the external additive from being embedded in the toner, and stably charge and develop for a long period of time. Is to maintain. Therefore, the cleaning blade is worn by a large number of external additives, and the external additives cover the surface of the toner particles, so that the fixability is lowered. Further, there is a problem that the small particle size / spherical toner is difficult to clean. In addition, an image forming apparatus using an intermediate transfer member is not taken into consideration, and further, there is a problem that an external additive in transfer is detached.
Further, Patent Document 5 has a problem that even an image forming apparatus using an intermediate transfer medium does not use an external additive having a large particle size, and it is difficult to obtain a stable toner over a long period of time. .

  Therefore, the present invention has been made in view of the above problems, and the problem is that the wear of the cleaning blade in the image forming apparatus is reduced, the cleaning property of the small particle size and spherical toner is ensured, and the transfer is performed. It is an object of the present invention to provide an image forming apparatus using a toner whose fixing property is hardly hindered by the toner after being applied.

The features of the present invention, which is a means for solving the above problems, are listed below.
The image forming apparatus of the present invention includes an image carrier that forms an electrostatic latent image by electrostatic charges, a latent image forming unit that exposes the image carrier to form a latent image, and a toner on the latent image on the surface of the image carrier. Developing means for supplying a visible image, transfer means for transferring onto a recording material via an intermediate transfer body that moves in contact with the image carrier, and transfer residual toner remaining on the surface of the image carrier after transfer An image forming apparatus comprising a cleaning unit having a cleaning blade for recovering the toner from the image carrier, wherein the toner contains at least 1.0 wt% or more of an inorganic oxide having an average particle size of 90 to 150 nm; Is a silica having a spherical shape, and the inorganic oxide content of the toner after being transferred from the image carrier to the intermediate transfer member is 75 to 95% of the initial inorganic oxide content of the toner. Transfer during transfer Inorganic oxide content of the toner after being transferred to the you, characterized in that to transfer a range of 75% to 95%.
Also, the image forming apparatus of the present invention, further, the silica is characterized by a silica by a sol-gel method.
The image forming apparatus of the present invention is further characterized in that the silica is externally added to the toner in an aqueous and / or alcohol solvent.
The image forming apparatus of the present invention is further characterized in that a plurality of image carriers are arranged in parallel in the moving direction of the intermediate transfer member.
The image forming apparatus of the present invention further includes a cleaning unit that arranges the cleaning blade in a canter manner with respect to the image carrier.
The image forming apparatus of the present invention further includes a coating device that applies a lubricant to the image carrier and / or the intermediate transfer member.

In the image forming apparatus of the present invention, the toner further has a weight average particle diameter D ₄ in the range of ₃ to 8 μm, and a ratio D ₄ / weight average particle diameter D ₄ to number average particle diameter D _n. A toner having a D _{n in} the range of 1.00 to 1.40 is used.
The image forming apparatus of the present invention is further characterized in that the toner has an average circularity in a range of 0.93 to 1.00.
Further, in the image forming apparatus of the present invention, the toner has a substantially spherical appearance, and a ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0. The ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0, and the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 is satisfied.
In the image forming apparatus of the present invention, the toner further includes a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium. The crosslinking and / or extension reaction is carried out in the presence of.
The image forming apparatus of the present invention further includes an image carrier and at least one of a charging unit, a developing unit, and a cleaning unit, and a process cartridge that is integrally supported and detachable from the main body of the image forming apparatus. It is characterized by that.

The toner of the present invention comprises an image carrier that forms an electrostatic latent image by electrostatic charge, a charging unit, a latent image forming unit that exposes the image carrier to form a latent image, and an image carrier. A developing means for supplying toner to the latent image on the surface so as to make it visible; a transfer means for transferring onto the recording material on the recording member that moves on the surface while being in contact with the image bearing member; In a toner used in an image forming apparatus including a cleaning unit having a cleaning blade for recovering a transfer residual toner remaining on the surface of an image carrier from an image carrier , an inorganic oxide having an average particle size of 90 to 150 nm is at least 1 0.0 wt% or more, and the inorganic oxide is a silica having a spherical shape, and the amount of the toner after being transferred from the image carrier to the intermediate transfer member with respect to the initial inorganic oxide content of the toner. Inorganic oxide content Characterized in that it is allowed to transfer in the range of 75% to 95%.
The toner of the present invention is further used in any of the image forming apparatuses described above.
The toner of the present invention, the further, Weight average particle diameter _{D 4} is in the range of 3 to 8 [mu] m, the ratio _D 4 / _{D n} of the weight average particle diameter _{D 4} and the number average particle diameter _{D n,} The toner is in the range of 1.00 to 1.40.
The toner of the present invention is further characterized in that the average circularity is in the range of 0.93 to 1.00.
Further, the toner of the present invention has a substantially spherical appearance, and the ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0. The ratio (r3 / r2) is in the range of 0.7 to 1.0, and the relationship of long axis r1 ≧ short axis r2 ≧ thickness r3 is satisfied.
Further, the toner of the present invention further comprises a cross-linking of a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in the presence of resin fine particles in an aqueous medium. And / or an extension reaction.

  In the image forming apparatus of the present invention, the external additive is also transferred together with the transfer of the toner in the transfer by means for solving the above, and the secondary transfer rate from the intermediate transfer member can be increased. In addition, since a certain amount of external additive is desorbed from the toner, it is possible to suppress a decrease in fixability due to the external additive, and the inorganic oxide that is desorbed during transfer and remains on the photoreceptor is cleaned. This has the effect that the small particle size / spherical toner can be cleaned by being dammed by the blade.

The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.
FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus 100 according to an embodiment of the present invention. Here, an embodiment applied to the electrophotographic image forming apparatus 100 will be described. The image forming apparatus 100 includes yellow (hereinafter referred to as “Y”), cyan (hereinafter referred to as “C”), magenta (hereinafter referred to as “M”), black (hereinafter referred to as “K”). An image forming apparatus (hereinafter, referred to as “tandem type”) 100 that forms a color image from four color toners. The image forming apparatus 100 includes four photoreceptors 1Y, 1C, 1M, and 1K as latent image carriers. Here, the drum-shaped photosensitive member 1 is taken as an example, but a belt-shaped photosensitive member can also be adopted. Each of the photoconductors 1Y, 1C, 1M, and 1K is rotationally driven in the direction of the arrow in the drawing while being in contact with the intermediate transfer belt 6a that is an intermediate transfer member that is a surface moving member. Each of the photoreceptors 1Y, 1C, 1M, and 1K is rotationally driven in the direction of the arrow in the drawing while being in contact with the intermediate transfer belt 6a.

  FIG. 2 is a schematic view showing the configuration of the process cartridge 2 in which the photoreceptor 1 is disposed. Since the configuration around each of the photoreceptors 1Y, 1C, 1M, and 1K in the process cartridges 2Y, 2C, 2M, and 2K is the same, only one process cartridge 2 is illustrated, and reference numerals Y, C, and M and K are omitted. Around the photosensitive member 1, along the surface movement direction, a developing device 5 that visualizes a latent image to form a toner image, and a neutralizing device before cleaning (hereinafter referred to as "PCL") that neutralizes the charged potential of the photosensitive member 1. 20. A lubricant application device 21 for applying a lubricant to the photosensitive member 1, a cleaning device 7 for cleaning residual toner on the photosensitive member 1, and a charging device 3 for charging the photosensitive member 1 are arranged in this order. Yes.

The configuration of the image forming apparatus 100 of the present invention will be described with reference to FIGS.
The charging device 3 charges the surface of the photoreceptor 1 to a negative polarity. The charging device 3 in the present embodiment includes a charging roller 3a as a charging member that performs a charging process by a so-called contact / proximity charging method. That is, the charging device 3 charges or charges the surface of the photosensitive member 1 by bringing the charging roller 3a into contact with or close to the surface of the photosensitive member 1 and applying a bias to the charging roller 3a. A DC charging bias is applied to the charging roller 3a so that the absolute value of the surface potential of the photoreceptor 1 is 200 to 700V. Note that a charging bias in which an AC bias is superimposed on a DC bias can also be used. The charging device 3 is provided with a cleaning roller 3b for cleaning the surface of the charging roller 3a. Further, even when toner is slightly adhered, the surface of the charging roller 3a may be cleaned by the cleaning roller 3b in order to prevent charging failure such as charging unevenness by the charging roller 3a. As the charging device 3, a thin film may be wound around both end portions in the axial direction on the peripheral surface of the charging roller 3 a and installed so as to contact the surface of the photoreceptor 1. As a result, the surface of the charging roller 3a and the surface of the photoreceptor 1 are extremely close to each other with a distance corresponding to the thickness of the film. As a result, contact with residual toner on the photoreceptor 1 can be reduced.
An electrostatic latent image corresponding to each color is formed on the surface of the photoreceptor 1 charged in this manner by exposure by the exposure device 4. The exposure device 4 writes an electrostatic latent image corresponding to each color on the photoreceptor 1 based on image information corresponding to each color. The exposure apparatus 4 of the present embodiment is a laser type exposure apparatus, but other types of exposure apparatuses such as an exposure apparatus including an LED array and an image forming unit may be employed.

In the developing device 5, a developing roller 5a as a developer carrying member is partially exposed from an opening of the casing. Here, a two-component developer composed of a toner and a carrier is used, but a one-component developer not containing a carrier may be used. The developing device 5 receives replenishment of the corresponding color toner from the toner bottle and accommodates it inside. The developing roller 5a is composed of a magnet roller as magnetic field generating means and a developing sleeve that rotates coaxially therearound. The carrier in the developer is transferred to the developing area facing the photosensitive member 1 in a state where it stands on the developing roller 5a by the magnetic force generated by the magnet roller. Here, the developing roller 5 a moves in the same direction at a linear velocity faster than the surface of the photosensitive member 1 in a region facing the photosensitive member 1 (hereinafter referred to as “developing region”). Then, the carrier spiked on the developing roller 5a supplies the toner adhered to the carrier surface to the surface of the photosensitive member 1 and develops it while sliding on the surface of the photosensitive member 1. At this time, a developing bias of about 300 V is applied to the developing roller 5a from a power source (not shown), whereby a developing electric field is formed in the developing region.
The intermediate transfer belt 6a in the transfer device 6 is stretched around three support rollers 6b, 6c, and 6d, and is configured to endlessly move in the direction of the arrow in the figure. On the intermediate transfer belt 6a, the toner images on the photoreceptors 1Y, 1C, 1M, and 1K are transferred so as to overlap each other by an electrostatic transfer method. Although there is a configuration using a transfer charger in the electrostatic transfer system, a configuration using a transfer roller 6e that generates less transfer dust is adopted here. Specifically, the primary transfer rollers 6eY, 6eC, 6eM, and 6eK as the transfer devices 6 are disposed on the back surface of the portion of the intermediate transfer belt 6a that is in contact with each of the photoreceptors 1Y, 1C, 1M, and 1K. . Here, a primary transfer region is formed by the portion of the intermediate transfer belt 6 a pressed by the primary transfer roller 6 e and the photosensitive member 1. When transferring the toner images on the photoreceptors 1Y, 1C, 1M, and 1K onto the intermediate transfer belt 6a, a positive bias is applied to the primary transfer roller 6e. Accordingly, each primary transfer area (hereinafter referred to as a transfer area) is described. ) Is formed, and the toner images on the photoreceptors 1Y, 1C, 1M, and 1K are electrostatically attached to the intermediate transfer belt 6a and transferred.

A belt cleaning device 15 for removing toner remaining on the surface of the intermediate transfer belt 6a is provided around the intermediate transfer belt 6a. The belt cleaning device 15 is configured to collect unnecessary toner adhering to the surface of the intermediate transfer belt 6a with a fur brush and a cleaning blade 7a. The collected unnecessary toner is transported from the belt cleaning device 6f to a waste toner tank (not shown) by a transport means (not shown). The transfer belt 6a is a high-resistance endless single-layer belt having a volume resistivity of 10 ⁶ to 10 ¹¹ Ωcm, and is a single-layer resin layer or a plurality of resins.
Further, a transfer device 9 is arranged in the right direction of FIG. The transfer device 9 includes a transfer conveyance belt 9a and a transfer roller 9b. The toner image superimposed on the intermediate transfer belt 6a, which is an intermediate transfer body, is transferred onto the recording paper conveyed from the paper supply unit 10 here. Therefore, in the apparatus 100 of the present invention, the toner is transferred twice to form an image on the recording paper. The transfer of the transfer device 9 is performed by applying a voltage having a polarity opposite to that of the toner to the transfer roller 9b. A secondary transfer region is formed between the intermediate transfer belt 6a and the secondary transfer roller 9b, and a recording sheet as a recording member is fed into this portion at a predetermined timing. This recording paper is accommodated in a paper feed cassette 10 on the lower side of the exposure device 4 in the drawing, and is conveyed to the secondary transfer region by a pickup roller, a registration roller pair 11 and the like. Then, the toner images superimposed on the intermediate transfer belt 6a are collectively transferred onto the recording paper on the transfer conveyance belt 9a in the secondary transfer region. During the secondary transfer, a positive bias is applied to the secondary transfer roller 9b, and the toner image on the intermediate transfer belt 6a is transferred onto the recording paper by the transfer electric field formed thereby.

Here, the lubricant application device 21 includes a lubricant molded body 21b housed in a fixed case, and a brush roller 21a that contacts the lubricant molded body 21b to scrape off the lubricant and apply it to the photoreceptor 1. And a pressurizing spring 21c that presses the lubricant molding 21b against the brush-like roller 21a. The lubricant molding 21 b is formed in a rectangular parallelepiped shape, and the brush roller 21 b has a shape extending in the axial direction of the photoreceptor 1. The lubricant molded body 21b is urged by a pressure spring 21c against the brush roller 21a so that almost all of the molded lubricant 21b can be used up. Since the molded lubricant 21b is a consumable product, its thickness decreases with time, but since it is pressurized by the pressure spring 21c, it is always in contact with the brush roller 21a.
The lubricant applying device 21 may be provided in the cleaning device 7 together with a cleaning blade 7a as a cleaning means. As a result, by rubbing the photosensitive member 1 with the brush-like roller 21a, it is possible to easily collect the toner attached to the brush by the lubricant molded body 21b or the flicker.
Examples of the lubricant include fatty acid metal salts, silicone oils, fluororesins, and the like, and these can be used alone or in combination of two or more. In particular, fatty acid metal salts are preferred. As the fatty acid metal salt, as the fatty acid, a linear hydrocarbon is preferable, and for example, myristic acid, palmitic acid, stearic acid, oleic acid and the like are preferable, and stearic acid is more preferable. Examples of the metal include lithium, magnesium, calcium, strontium, zinc, cadmium, aluminum, cerium, titanium, and iron. Among these, zinc stearate, magnesium stearate, aluminum stearate, iron stearate and the like are preferable, and zinc stearate is most preferable.

The cleaning device 7 includes a cleaning blade 7a, a support member 7b, a toner recovery coil 7c, and a blade pressure spring 7d. The cleaning blade 7a removes the toner on the photoreceptor 1 remaining after the transfer. The support member 7b is attached to the cleaning device by being attached to the support member 7b, but the support member 7b is not particularly limited, but metal, plastic, ceramic, or the like can be used.
In the cleaning blade 7a, examples of the elastic body having a low friction coefficient include urethane elastomer, silicone elastomer, and fluorine elastomer among urethane resin, silicone resin, and fluororesin. As the cleaning blade 7a, a thermosetting urethane resin is preferable, and a urethane elastomer is particularly preferable from the viewpoints of wear resistance, ozone resistance, and contamination resistance. Elastomer includes rubber. The cleaning blade 7a preferably has a hardness (JIS A) in the range of 65 to 85 degrees. The cleaning blade 7a preferably has a thickness of 0.8 to 3.0 mm and a protrusion amount of 3 to 15 mm. Further, as other conditions, the contact pressure, the contact angle, the amount of biting, and the like can be determined as appropriate.

In the image forming apparatus 100 having the above-described configuration, at least 90 to 300 nm of inorganic oxide is contained in the toner in an amount of 0.4 wt% or more, and from the photoreceptor 1 to the intermediate transfer belt 6a with respect to the initial inorganic oxide content of the toner. After the transfer, the toner is transferred so that the inorganic oxide content of the toner is in the range of 75 to 95%. Therefore, the image forming apparatus 100 of the present invention externally adds an inorganic oxide of 90 to 300 nm to the toner used here. When the average particle size of the inorganic oxide is less than 90 nm, the inorganic oxide is buried in the toner by use over time in which the toner receives an impact force by stirring and mixing with the carrier or the toners in the developing device 5. When the average particle diameter exceeds 300 nm, the inorganic oxide easily desorbs from the toner surface, and is desorbed from the toner surface by mixing and stirring in the developing device 5 to change the toner characteristics. Will occur. The average particle size of the inorganic oxide is more preferably 90 to 150 nm.
Further, the content is 0.4 wt% or more based on the toner. Since the inorganic oxide has a large particle size, the number per unit weight is small, and if it is less than 0.4 wt%, the number of inorganic oxides on the toner surface is small and the effect of improving the transfer rate is small. However, it does not exceed 5 wt%. If it exceeds 5 wt%, the amount present on the toner surface is large, and the toner surface is covered and the additive floats, causing an abnormal image.

Examples of the inorganic oxide of 90 to 300 nm of the present invention include silicon oxide, aluminum oxide, titanium oxide, zirconium oxide, iron oxide, magnesium oxide, calcium oxide, manganese oxide, zinc oxide, strontium oxide, strontium titanate, and barium acid value. , Acid value cesium and the like, or other inorganic oxides. Interoxide compounds such as strontium titanate and barium titanate can also be used.
Furthermore, among these oxides, silicon oxide is preferable. In the case of silicon oxide, the color is white and it can be used for a color toner, and is highly safe. As manufacturing methods, two types of manufacturing methods have been established, and amorphous and spherical shapes can be easily produced. In the case of the amorphous form, there is a combustion type silica in which silicon tetrachloride is burned in the gas phase, and in the case of the spherical form, there is a method for producing silicon oxide by a sol-gel method in which silicon oxide is precipitated in the aqueous phase. In the sol-gel method, alkoxysilane is hydrolyzed and condensed in an aqueous solution to deposit silicon oxide. Examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetraisoproxysilane, and tetrabutoxysilane. Examples of the hydrolysis catalyst include ammonia, urea, monoamine and the like.
The inorganic oxide enters between the toner base and the photoreceptor 1 and the intermediate transfer belt 6a and functions as a spacer. By making the inorganic oxide spherical, the contact area can be reduced, and toner transfer can be improved.

  Furthermore, it is effective to perform a surface modification treatment with a hydrophobizing agent or the like. Representative examples of the hydrophobizing agent include dimethyldichlorosilane (DDS), trimethylchlorosilane, methyltrichlorosilane, allyldimethyldichlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α -Chlorethyltrichlorosilane, p-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, chloromethyltrichlorosilane, hexamethyldisilazane (HMDS), hexaphenyldisilazane, hexatolyldisilazane and the like.

  The toner used here includes a pulverization method, a polymerization method (suspension polymerization, emulsion polymerization dispersion polymerization, emulsion aggregation, emulsion association, etc.), but is not limited to these production methods. As an example of the pulverization method, first, the above-mentioned resin, pigment or dye as a colorant, charge control agent, release agent, other additives, etc. are sufficiently mixed by a mixer such as a Henschel mixer, and then batch type. The constituent materials are well kneaded using a two-roll, Banbury mixer, continuous twin-screw extruder, continuous single-screw kneader, or the like, and cut after rolling and cooling. The toner kneaded product after cutting is crushed, coarsely pulverized using a hammer mill, etc., and further pulverized by a fine pulverizer or mechanical pulverizer using a jet stream, and a classifier or Coanda effect using a swirling airflow Is classified to a predetermined particle size by a classifier using Thereafter, inorganic fine particles are externally added by a mixer and mixed to obtain a toner. Moreover, an example of the polymerization method is shown. Use of a toner in which a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is crosslinked and / or extended in the presence of resin fine particles in an aqueous medium. preferable.

Further, fine particles can be added to the toner in addition to the inorganic oxide described above. Specific examples of the 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, and diatomaceous earth. And chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. In addition, polymer fine particles, such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, methacrylic acid ester, acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine, nylon, thermosetting Polymer particles made of resin may be used. 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. It is done. In particular, it is preferable to use hydrophobic silica and hydrophobic titanium oxide obtained by subjecting silica and titanium oxide to the above surface treatment. The primary particle diameter of the fine particles is preferably 8 to 80 nm, and particularly preferably 8 to 50 nm. The use ratio of the fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.1 to 2.0 wt%.
As a method for containing these 90 to 300 nm inorganic oxides and fine particles, the fine particles and toner base particles are usually placed in a mixer and stirred.
As another method, the toner can be externally added in a water-based and / or alcohol-based solvent. An inorganic oxide is added to the toner dispersed in an aqueous solvent and adhered to the toner surface. Further, when this inorganic oxide has been subjected to a hydrophobization treatment, it may be dispersed after a small amount of alcohol or the like is used in combination to lower the interfacial tension to facilitate wetting. Thereafter, the solvent can be removed by heating and fixed to prevent desorption. Thereby, the inorganic oxide can be uniformly dispersed on the toner surface.
Further, when the toner and the additive are dispersed in the aqueous solvent, the additive can be dispersed more uniformly on the toner surface by adding the surfactant. Furthermore, it is preferable to use a surfactant having a reverse polarity to the inorganic oxide and the toner.
Further, since the amount of inorganic oxide after transfer varies in the case of non-uniform dispersion, the inorganic oxide content of the toner after being transferred from the photoreceptor 1 to the intermediate transfer belt 6a is stable in the range of 75 to 95%. In order to perform the image forming operation, it is preferable that the toner is externally added in an aqueous solvent and / or an alcohol solvent.

  The coating device 21 provided in the image forming apparatus 100 of the present invention reduces the interaction between the photoconductor 1 and the toner by reducing the coefficient of friction of the surface of the photoconductor 1 and the intermediate transfer belt 6a. The toner developed in the upper electrostatic latent image can be easily separated and the transfer rate can be increased. Further, it is possible to suppress an increase in friction between the cleaning blade 7a and the photosensitive member 1 and improve the cleaning property. As described above, it is preferable that the friction coefficient of the surface of the photoreceptor 1 is set to 0.4 or less by applying a lubricant to the surface of the photoreceptor 1. The coefficient of friction can be measured using an Euler belt type measuring device.

Furthermore, in the image forming apparatus 100 of the present invention, the inorganic oxide content of the toner after being transferred from the photoreceptor 1 to the intermediate transfer belt 6a is 75 to 95% with respect to the initial inorganic oxide content of the toner. Transfer within the range. The image quality and transfer rate due to the transfer are greatly affected by the transfer voltage, current value and toner charge amount, toner surface form, type of external additive on the toner surface, and addition amount. Furthermore, some external additives such as inorganic oxides on the toner surface are transferred together with the toner by transfer, and others are left on the photoreceptor 1.
FIG. 3 is a diagram schematically showing the force received by the external additive on the toner surface.
This is because the inorganic oxide sandwiched between the toner on the photoconductor 1 and the photoconductor 1 has an electrostatic force on the photoconductor 1 due to the force of the electric field generated by the transfer roller 6e and the charge of the external additive. The latent image receives an electrical attraction force and a physical adhesion force with the photoreceptor 1. The amount of inorganic oxide remaining is determined by the balance between these two forces. The toner and the inorganic oxide have different detachment forces due to electrostatic force, van der Waals force, the amount of the inorganic oxide sticking to the toner surface, the adhesiveness of the toner surface, and the like. By controlling these forces, the amount of inorganic oxide remaining in the toner during primary transfer is controlled to 75 to 95%. Specifically, the amount of the inorganic oxide that pierces the toner surface is controlled by the mixing strength at the time of adding the inorganic oxide, or the stirring strength in the step of externally adding to the toner in an aqueous and / or alcohol solvent. Control is performed according to the type of surfactant.

At this time, the inorganic oxide remaining on the photoreceptor 1 reaches the cleaning device 7. The cleaning blade 7a in the cleaning device 7 is arranged in a counter manner. Compared with the trailing method, the counter method is less likely to cause a cleaning failure and less likely to cause a cleaning abnormality due to the occurrence of bounding and chatter noise. Even if the toner particles have a small particle size and are made spherical and have low cleaning properties, the toner used in the present invention contains an inorganic oxide, thereby reducing the adhesion between the transfer residual toner and the photoreceptor 1. By doing so, it is possible to clean with the cleaning blade 7a.
Further, when the inorganic oxide released from the toner by the transfer reaches the cleaning blade 7a, the inorganic oxide is dammed and stays at the tip of the cleaning blade, thereby contributing to cleaning of the toner that reaches the cleaning blade 7a thereafter.

The recording paper on which the toner image is transferred from the intermediate transfer belt 6a is then conveyed to the fixing device 8. Many inorganic oxides and external additives have high heat capacities and do not melt at 100 to 250 ° C. For this reason, if there is a lot of inorganic oxide or the like on the toner surface, the contact with the heating roller 8a and the pressure roller 8b of the fixing device 8 reduces the chance of direct contact with the toner particles. Since there are many cases where the transmission is low, the temperature of the toner particles is hardly increased, and the fixing property of the toner is lowered. Furthermore, since a large amount of external additives are present on the toner surface, dissolution of the release agent contained in the toner is hindered, and offset tends to occur. Further, since the fine particle external additive has a small particle size, the number of particles per unit weight is large, and the toner surface is widely covered. However, since the particle size is small, the contact between the toner particles underneath and the heating roller 8a and the like is hindered. Further, as the particle size increases, the number of particles at least prevents the heating roller 8a and the like from contacting each other. . Therefore, the number of inorganic oxides in the range that can be visually recognized by 15,000 times SEM observation is set to 10% or less of the initial value on the recording paper on which the toner image is transferred from the intermediate transfer belt 6a. This is because, by stirring the developer in the developing section, the toner is hazarded and the additive is buried in the toner surface, or the additive is detached when transferring from the photoreceptor 1 to the intermediate transfer belt 6a, and the intermediate transfer belt 6a. Can be controlled by detachment of the additive at the time of transfer to the recording paper. Specifically, it can be controlled by adjusting the surface hardness of the toner base, controlling the hazard applied to the toner in the developing portion by the stirring strength, or changing the additive adhesion strength on the toner surface. Thus, by reducing the external additive on the toner surface so that it cannot be observed, it is possible to prevent a decrease in toner fixability.
With respect to the inorganic oxide content in the initial stage of the toner, the inorganic oxide content in the toner after being transferred from the photoreceptor 1 to the intermediate transfer belt 6a is measured using fluorescent X-ray measurement. The initial toner and the toner transferred to the intermediate transfer belt 6a are collected, and the amount of the element contained in the inorganic oxide is determined by fluorescent X-rays. At this time, if the same amount of toner is compressed and shaped, X-rays are uniformly irradiated, and the measurement accuracy is improved. As a direct method, the amount of inorganic oxide in the toner may be directly measured by ICP.

In the image forming apparatus according to the present invention, the toner used in the developing device 5 is a toner having an average circularity of 0.93 to 1.00, a weight average particle diameter D4 of ₃ to 8 μm, and a weight average particle diameter. A toner having a small particle size and a narrow particle size distribution in which the ratio D ₄ / D _{n of} D ₄ to the number average particle size D _n is in the range of 1.00 to 1.40 is preferable. By using a toner having a small particle diameter, the toner can be densely attached to the latent image. Further, by narrowing the particle size distribution, the toner charge amount distribution becomes uniform, a high-quality image with little background fogging can be obtained, and the transfer rate can be increased.

The toner used in the developing device 5 is preferably a toner that can be defined by the values of the following shape factors SF-1 and SF-2. FIG. 4 is a diagram schematically showing the shape of the toner in order to explain the shape factor SF-1 and the shape factor SF-2.
The shape factor SF-1 indicates the ratio of the roundness of the toner shape and is represented by the following formula (1). This is a value obtained by dividing the square of the maximum length MXLNG of the shape formed by projecting the toner on a two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-1 = {(MXLNG) ² / AREA} × (100π / 4) (1)
When the value of SF-1 is 100, the shape of the toner becomes a true sphere, and becomes larger as the value of SF-1 increases.
The shape factor SF-2 indicates the ratio of the unevenness of the toner shape, and is represented by the following formula (2). A value obtained by dividing the square of the perimeter PERI of the figure formed by projecting the toner on the two-dimensional plane by the figure area AREA and multiplying by 100π / 4.
SF-2 = {(PERI) ² / AREA} × (100 / 4π) (2)
When the value of SF-2 is 100, there is no unevenness on the toner surface, and as the value of SF-2 increases, the unevenness of the toner surface becomes more prominent.
Specifically, the shape factor is measured by taking a photograph of the toner with a scanning electron microscope (S-800: manufactured by Hitachi, Ltd.), introducing it into an image analyzer (LUSEX 3: manufactured by Nireco) and analyzing it. Calculated.

  The toner according to the present invention is a toner having SF-1 in the range of 100 to 180 and SF-2 in the range of 100 to 180. When the shape of the toner is close to a spherical shape, the contact between the toner and the toner or the toner and the photosensitive member 1 becomes a point contact, so that the adsorbing force between the toners becomes weak and the fluidity increases, and the toner and the photosensitive member. The adhesion with 1 is weakened and the transfer rate is increased. On the other hand, since the true spherical toner tends to enter the gap between the cleaning blade 7a and the photoreceptor 1, it is preferable that the toner shape factors SF-1 and SF-2 be large to some extent. Will be scattered and image quality will deteriorate. For this reason, it is preferable that SF-1 and SF-2 do not exceed 180.

  A toner suitably used in the image forming apparatus 100 of the present invention is 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 are dispersed in an organic solvent. A toner obtained by crosslinking and / or elongation reaction in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(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).

(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.

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

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

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle diameter of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.
Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
(Toner production method)
1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.
The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added.
As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium 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).

As the cationic surfactants, aliphatic primary to have a fluoroalkyl group, 2 primary or secondary amine acids, aliphatic quaternary ammonium, such as perfluoroalkyl (C6-C10) sulfonamide propyl trimethyl ammonium salt 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 and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao Corporation), SGP (manufactured by Soken Co., Ltd.), 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 Such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

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

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

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

Further, the toner according to the present invention has a substantially spherical shape and can be represented by the following shape rule.
FIG. 5 is a diagram schematically showing the shape of the toner according to the present invention. In FIG. 5, when a substantially spherical toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), the toner of the present invention has a major axis and a minor axis. The ratio (r2 / r1) (see FIG. 5B) is 0.5 to 1.0, and the ratio of thickness to minor axis (r3 / r2) (see FIG. 5C) is 0.7 to 1.0. It is preferable to be in the range of 1.0. When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.
Note that r1, r2, and r3 were measured with a scanning electron microscope (SEM) while changing the angle of field of view and taking pictures.

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, The weight average particle diameter D ₄ is preferably 20 to 100 μm. 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 high saturation magnetization, but can be appropriately selected according to the process of the image forming apparatus. 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.

  The image forming apparatus 100 according to the present invention includes a photosensitive member 1 and one or more devices selected from a coating device 21, a charging device 3, a developing device 5, and a cleaning device 7, which are integrally supported to be attached and detached. A possible process cartridge is provided. Accordingly, the developer and the developing device 5 can be easily replaced, and the main body of the image forming apparatus 100 can be used for a long time.

Hereinafter, the present invention will be described in more detail based on examples.
Example 1
~ Synthesis of organic fine particle emulsion ~
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 charged and stirred for 15 minutes at 400 rpm, a white emulsion was obtained. This was heated to raise the temperature in the system 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, and an aqueous vinyl resin (a copolymer of sodium salt of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate). A dispersion was obtained. This is designated as [fine particle dispersion 1].
[Fine particle dispersion 1 used as a sample, the weight average particle diameter _{D 4} of the measurement of the LA-920 (manufactured by HORIBA) was 105 nm. Moreover, a part 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.

~ Preparation of aqueous phase ~
990 parts of water, 80 parts of [fine particle dispersion 1], 37 parts of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate were mixed and stirred. A liquid was obtained. This is designated [Aqueous Phase 1].
~ Synthesis of ketimine ~
170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged into a reaction vessel equipped with a stirrer and a thermometer, and reacted at 50 ° C. for 5 hours to obtain a blocked amine. This is referred to as [ketimine compound 1]. The amine value of this [ketimine compound 1] was 418.
~ Preparation of masterbatch ~
1200 parts water, 40 parts carbon black (manufactured by Cabot, Regal 400R), 60 parts polyester resin (manufactured by Sanyo Chemical Industries, RS801), 30 parts water, and mixed with a Henschel mixer (manufactured by Mitsui Mining) The mixture was kneaded at 150 ° C. for 30 minutes using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain a carbon black masterbatch. This is designated as [Masterbatch 1].

~ Preparation of oil phase ~
A container equipped with a stir bar and a thermometer was charged with 400 parts of [low molecular weight polyester 1], 110 parts of carnauba wax, and 947 parts of ethyl acetate, heated to 80 ° C. with stirring, and maintained at 80 ° C. for 5 hours. Thereafter, it was cooled to 30 ° C. over 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain a dissolved product. This is referred to as [raw material solution 1].
[Raw Material Solution 1] Transfer 1324 parts to a container and use a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), liquid feeding speed: 1 Kg / hr, disk peripheral speed: 6 m / sec, 0.5 mm zirconia bead filling amount : The wax was dispersed under the conditions of 80% by volume and the number of passes: 3 times. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, and a dispersion was obtained by using a bead mill under the same conditions as described above, with the number of passes being one time. This is designated as [Pigment / Wax Dispersion 1].

~ Emulsification ~
[Pigment / Wax Dispersion 1] 1772 parts, 50% ethyl acetate solution of [Prepolymer 1] (number average molecular weight 3800, weight average molecular weight 15000, Tg 60 ° C., acid value 0.5, hydroxyl value 51, and free isocyanate contained The amount is 1.53% by weight) 100 parts and [ketimine compound 1] 8.5 parts in a container, and after mixing for 1 minute at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika) 1,200 parts of [Aqueous Phase 1] was added and mixed with a TK homomixer at a rotation speed of 10,000 rpm for 20 minutes to obtain an aqueous medium dispersion. This is designated as [Emulsified slurry 1].
~ Deorganic solvent ~
[Emulsified slurry 1] is put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging is carried out at 45 ° C. for 4 hours to obtain a dispersion in which the organic solvent is distilled off. It was. This is designated as [Dispersion Slurry 1].
~ Washing and drying ~
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1) 100 parts of ion-exchanged water was added to the filter cake and mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes), followed by filtration.
(2) 100 parts of a 10% sodium hydroxide aqueous solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3) 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes), and then filtered.
(4) 300 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes) and then filtered twice to obtain a filter cake.
This filter cake was dried at 45 ° C. for 48 hours in a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner base particles. This is referred to as [Toner Base 1]. [Toner base 1] has a weight average particle diameter _{D 4} is 6.05Myuemu, number average particle diameter _{D n} is _{5.68μm, D 4 / D n =} 1.07, R2 / R1 = 0.92, R3 / R2 = 0.96.

Preparation ~ of ~ spherical hydrophobic silica
Tetramethoxysilane and aqueous ammonia were reacted at 50 ° C. to obtain spherical silica by the sol-gel method. After washing with water, without drying, silica was dispersed in toluene using methanol, and hexamethyldisilazane (HMDS) treatment was performed to obtain [Inorganic oxide particles 1]. The inorganic oxide particles were stirred in methanol with an ultrasonic disperser, and the average particle size D ₅₀ was measured with a laser diffraction / scattering particle size distribution device.
~ Mixing of external additives ~
100 parts by weight of [Toner Base 1] obtained above, 1.0 part of [Inorganic Oxide Particles 1], 0.5 weight of hydrophobic silica (HDK H1303, Clariant Japan, average particle diameter D ₅₀ : 13 nm) The toner was obtained by mixing the parts with a Henschel mixer 20B manufactured by Mitsui Mining Co., Ltd. at a rotating speed of 2500 rpm for 3 minutes, and passing through a sieve having an opening of 38 μm to remove aggregates.

< Preparation of two-component developer>
When evaluating the image quality and the like of a copied image in this example and the comparative example, the performance of the toner of the present invention as a two-component developer was evaluated.
As a carrier used for the two-component developer, a ferrite carrier having an average particle diameter of 35 μm coated with a silicone resin with an average thickness of 0.5 μm is used, and 8 parts by weight of toner is contained in 100 parts by weight of the carrier. A developer was prepared by uniformly mixing and charging using a tumbler mixer of the type that is rolled and stirred.
The carrier was prepared as follows. As a core material, 5000 parts of Mn ferrite particles (weight average diameter: 35 μm), and as a coating material, 450 parts of toluene, 450 parts of silicone resin SR2400 (made by Toray Dow Corning Silicone, nonvolatile content 50%), aminosilane SH6020 ( Using a coating liquid prepared by dispersing 10 parts of Toray Dow Corning Silicone) and 10 parts of carbon black with a stirrer for 10 minutes, the core material, the coating liquid, and a rotating bottom plate disk in the fluidized bed The coating liquid was applied to the core material by applying the coating liquid while forming a swirling flow provided with stirring blades. The obtained coated material was baked in an electric furnace at 250 ° C. for 2 hours to obtain the carrier.

<Image quality evaluation machine for copied images>
The black toner obtained in Example 1 below was evaluated for image quality and the like with only one black toner using the prototype shown in FIG.

(Examples 2 and 3 and Reference Example 1 )
In Examples 2 and 3 and Reference Example 1 , as shown in Table 1, image quality and the like were evaluated in the same manner as in Example 1 except that the types and amounts of inorganic oxides and external additives were changed. In Example 3, 0.5 parts by weight of hydrophobic titanium oxide (MT-150AI, manufactured by Teika, average particle diameter D ₅₀ : 15 nm) is additionally added. In Reference Example 1 , strontium titanate (SW-320, titanium industry, average particle size D ₅₀ : 270 nm) was used as the inorganic oxide.
( Reference Example 2 )
As the inorganic oxide, combustion type silica [inorganic oxide fine particles 2] in which silicon tetrachloride is burned in the gas phase was used. An average particle diameter D ₅₀ is 150 nm, dimethyldichlorosilane (DDS), in was used after subjected to surface treatment. A toner was prepared and evaluated in the same manner as in Example 1 with the formulation shown in Table 1.
(Example 4 )
100 parts by weight of [Toner Base 1] was dispersed in distilled water to a solid content of 10% by weight. On the other hand, 1.0 part by weight of [inorganic oxide fine particles 1] and 0.5 part by weight of hydrophobic silica (HDK H1303, manufactured by Clariant Japan) are 0.2 parts by weight of stearylamine acetate, 70 parts by weight of ion-exchanged water, The solution was gradually added to a solution of 30 parts by weight of methanol with stirring to obtain a dispersion of silica fine particles. The obtained silica fine particle dispersion was mixed with the above toner particle dispersion and then stirred for 1 hour at room temperature, followed by filtration and separation, and the resulting cake was dried under reduced pressure at 40 ° C. for 24 hours to obtain toner particles.
(Example 5 )
~ Preparation of pulverized toner ~
65 parts by weight of polyester resin A for toner (acid value: 2.7, Tm: 106 ° C., Tg: 64, Mn: 2600, Mw: 13000), polyester resin B for toner (acid value: 19, Tm: 121 ° C., Tg: 65, Mn: 2500, Mw: 299000) 35 parts by weight, carnauba wax 5 parts by weight, carbon black: 6 parts by weight are mixed and kneaded in a twin-screw kneader, and in a Hosokawa Micron counter jet mill. After pulverization, fine powder was cut with a TTSP classifier manufactured by Hosokawa Micron to obtain [Toner Base Particles 2]. Toner Base 2] has a weight average particle diameter _{D 4} is 6.65Myuemu, number average particle diameter _{D n} is _{5.08μm, D 4 / D n =} 1.31, R2 / R1 = 0.84, R3 / R2 = 0.82. A toner was prepared and evaluated in the same manner as in Example 1 with the formulation shown in Table 1.
(Comparative Examples 1 to 5 )
In Comparative Examples 1 to 5 , as shown in Table 1, the image quality and the like were evaluated in the same manner as in Example 1 except that the types and amounts of inorganic oxides and external additives were changed. In Comparative Examples 1 and 4 , in order to loosely adhere the base toner and the additive, a Henschel mixer 20B manufactured by Mitsui Mining Co., Ltd. was used, and the toner was obtained by mixing at a rotation speed of 1000 rpm for 3 minutes. In Comparative Examples 2 and 5 , in order to firmly adhere the base toner and the additive, a Q mixer 20B manufactured by Mitsui Mining Co., Ltd. was used for mixing for 3 minutes at a stirring speed of 6000 rpm to obtain a toner. In Comparative Example 3, a toner having no inorganic oxide of 90 to 300 nm was obtained .

The inorganic oxide of Reference Example 1 is amorphous strontium titanate, and the combustion silica that is the inorganic oxide of Reference Example 2 is amorphous.

As can be seen from Table 2, in Examples 1 to 5 and Reference Examples 1 and 2 , a residual rate of 75 to 95% of silica at the primary transfer rate is obtained by having a particle size in the range of 90 to 300 nm. It has been. In Comparative Examples 1 , 2, 4 and 5, the residual rate of silica is out of this range.

<Evaluation items>
The following items were evaluated for the performance of the toners obtained in the examples and comparative examples.
(1) Cleaning performance 20,000 images with an image ratio of 5% were output in the monochromatic mode, and the presence or absence of occurrence of cleaning failure was evaluated. The case where no cleaning failure occurred was “◯”, and the case where it occurred was “×”.
(2) Primary and secondary toner transfer rates
The toner transfer rate of primary transfer is the transfer rate of toner when transferring from the photoreceptor 1 to the intermediate transfer belt 6a, and the toner transfer rate of secondary transfer is the toner transfer rate when transferring from the intermediate transfer belt 6a to paper. With respect to the transfer rate, the transfer rate after outputting 10,000 images with an image ratio of 5% in the single color mode was measured.
(3) Text transfer white spot After running 15,000 image charts with 50% image area in single color mode, the text image is output to the RHP type DX OHP sheet, and the text line image inside It was visually evaluated whether there was toner untransferred from which the toner was removed. The case where no white spots occurred was “◯”, and the case where it occurred was “x”.
(4) Hot offset resistance / low-temperature fixability 0.85 ± 0.1 mg / cm ² of toner adhesion on solid and thick transfer paper (Ricoh type 6200 and NBS Ricoh copy printing paper) as a solid image The fixing performance was evaluated. A fixing test was performed by changing the temperature of the fixing device, and an upper limit temperature at which hot offset did not occur on plain paper was defined as an upper limit fixing temperature. Further, the minimum fixing temperature was measured with a thick paper. The lower limit fixing temperature was obtained by drawing the obtained fixed image with a load of 50 g using a drawing tester, and setting the fixing roller temperature at which the image was hardly scraped as the lower limit fixing temperature. Furthermore, the temperature ranges of the upper limit fixing temperature (hot offset resistance) and the lower limit fixing temperature (low temperature fixability) are shown.

In Examples 1 to 5 and Reference Examples 1 and 2 , no cleaning failure occurred. In Comparative Examples 2, 3, and 5 , since only a small amount of the inorganic oxide of 90 nm or more remained on the photoreceptor, a cleaning failure occurred.
In Examples 1 to 5 and Reference Examples 1 and 2, the transfer rate of primary and secondary toners is 90% or more, and good transferability is exhibited. In Comparative Examples 1, 3, and 4, additive desorption occurred during transfer, and the secondary toner transfer rate was 90% or less, and transferability was deteriorated.
In Examples 1 to 5 and Reference Examples 1 and 2 , there was no occurrence of white spots due to transfer. Additive during transfer is eliminated, because the cohesiveness is increased, in Comparative Example 1, 4, white spots occur in the character portion, in Comparative Example 3, no inorganic oxides 90～300Nm, character White spots occurred in the part.
In Examples 1 to 4 and Reference Examples 1 and 2 , the fixing temperature range was approximately 60 ° C., which was wider than 50 ° C. in Comparative Example 2 where the base toner was the same. Further, in Example 5 , the fixing temperature range was 55 ° C., which was wider than Comparative Example 5 where the base toner was the same.
6 and 7 show SEM photographs (15,000 times) of the new state of the toner of Example 3 and the state on paper. FIG. 6 is a photograph of the toner in the initial state observed with an SEM electron microscope, and FIG. 7 is a photograph of the toner on the paper after transfer, observed with an SEM electron microscope.
As is apparent from FIGS. 6 and 7, the toner on the paper has almost no visible inorganic oxide compared to the new toner, and the number of inorganic oxides is 10% or less compared to the initial toner. there were.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a process cartridge in which a photoconductor is disposed. FIG. 3 is a diagram schematically illustrating toner sandwiched between a photoreceptor and an intermediate transfer member. FIG. 6 is a diagram schematically illustrating the shape of a toner, where (a) illustrates a shape factor SF-1, and (b) illustrates a shape factor SF-2. 2A and 2B are schematic diagrams illustrating an outer shape of a toner, where FIG. 1A is an appearance of the toner, and FIG. 2B is a cross-sectional view of the toner. 3 is a photograph of the toner in an initial state observed with an SEM type electron microscope. It is the photograph by SEM type electron microscope observation of the toner on the paper after the transfer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Process cartridge 3 Charging apparatus 3a Charging roller 3b Cleaning roller 4 Exposure apparatus 5 Developing apparatus 5a Developing roller 5b Stirring conveyance screw 5c Doctor blade 6 Transfer apparatus 6a Intermediate transfer body 6b, 6c, 6d Support roller 6e Primary transfer roller 6f Belt cleaning device 7 Cleaning device 7a Cleaning blade 7b Support member 7c Recovery screw 7d Pressure spring 8 Fixing device 8a Heating roller 8b Pressure roller 9 Transfer conveyance device 9a Transfer conveyance belt 9b Secondary transfer roller 10 Paper feed unit 11 Registration roller 12 Paper discharge roller 20 Light emitting means (PCL)
DESCRIPTION OF SYMBOLS 21 Application | coating apparatus 21a Brush-like roller 21b Lubricant molding 21c Pressure spring 100 Image forming apparatus

Claims (17)

An image carrier that forms an electrostatic latent image by electrostatic charge, a latent image forming unit that exposes the image carrier to form a latent image, and supplies a toner to the latent image on the surface of the image carrier to make a visible image. Development means, transfer means for transferring onto the recording material via an intermediate transfer body that moves on the surface while being in contact with the image carrier, and cleaning for recovering transfer residual toner remaining on the surface of the image carrier after transfer from the image carrier In an image forming apparatus comprising a cleaning unit having a blade,
The image forming apparatus contains at least 1.0 wt% or more of an inorganic oxide having an average particle size of 90 to 150 nm in the toner,
The inorganic oxide is silica having a spherical shape;
Image formation characterized in that the inorganic oxide content of the toner after being transferred from the image carrier to the intermediate transfer member is transferred in the range of 75 to 95% with respect to the initial inorganic oxide content of the toner. apparatus. The image forming apparatus according to claim 1.
2. The image forming apparatus according to claim 1, wherein the silica is silica by a sol-gel method . The image forming apparatus according to claim 1, wherein
2. The image forming apparatus according to claim 1, wherein the silica is externally added to the toner in a water-based and / or alcohol-based solvent . The image forming apparatus according to any one of claims 1 to 3,
In the image forming apparatus, a plurality of image carriers are arranged in parallel in the moving direction of the intermediate transfer member . The image forming apparatus according to claim 1,
The image forming apparatus includes a cleaning unit that arranges a cleaning blade in a canter manner with respect to the image carrier . The image forming apparatus according to claim 1,
The image forming apparatus includes an application device that applies a lubricant to the image carrier and / or the intermediate transfer member . The image forming apparatus according to claim 1,
In the image forming apparatus, the weight average particle diameter D ₄ is in the range of ₃ to 8 μm, and the ratio D ₄ / D _n between the weight average particle diameter D ₄ and the number average particle diameter D _n is 1.00 to 1.n. An image forming apparatus using a toner in the range of 40 . The image forming apparatus according to claim 7 .
The image forming apparatus , wherein the toner has an average circularity in a range of 0.93 to 1.00 . The image forming apparatus according to claim 7 or 8 ,
The toner has a substantially spherical appearance,
The ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0. An image forming apparatus satisfying a relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 . The image forming apparatus according to any one of claims 7 to 9 ,
The toner, even without low, a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, a crosslinking a toner composition comprising a releasing agent in the presence of fine resin particles in an aqueous medium and / or elongation reaction image forming apparatus characterized by causing. The image forming apparatus according to claim 1 ,
The image forming apparatus includes an image carrier and at least one of a charging unit, a developing unit, and a cleaning unit, and includes a process cartridge that is integrally supported and detachable from the main body of the image forming apparatus. Forming equipment. An image carrier that forms an electrostatic latent image by an electrostatic charge, a charging unit that is in contact with or close to the surface of the image carrier, a latent image forming unit that exposes the image carrier to form a latent image, and an image carrier A developing unit that supplies toner to a latent image on the surface of the body to make it visible, a transfer unit that transfers the image onto a recording member that moves on the surface while being in contact with the image carrier, or an intermediate transfer member; In a toner used in an image forming apparatus including a cleaning unit having a cleaning blade for recovering transfer residual toner remaining on the surface of the image carrier later from the image carrier,
The toner contains at least 1.0 wt% of an inorganic oxide having an average particle size of 90 to 150 nm,
The inorganic oxide is silica having a spherical shape;
The toner is transferred in a range of 75 to 95% of the inorganic oxide content of the toner after being transferred from the image bearing member to the intermediate transfer member with respect to the initial inorganic oxide content of the toner.
Toner characterized by the above. The toner according to claim 12.
The toner used in the image forming apparatus according to claim 1 . The toner according to claim 12 or 13 ,
The toner has a weight average particle diameter D ₄ in the range of ₃ to 8 μm, and a ratio D ₄ / D _n between the weight average particle diameter D ₄ and the number average particle diameter D _{n of} 1.00 to 1.40. Toner characterized by being in range . The toner according to any one of claims 12 to 14 ,
The toner has an average circularity in a range of 0.93 to 1.00 . The toner according to any one of claims 12 to 15,
The toner has a substantially spherical appearance,
The ratio of the major axis to the minor axis (r2 / r1) is in the range of 0.5 to 1.0, and the ratio of the thickness to the minor axis (r3 / r2) is in the range of 0.7 to 1.0. And a toner satisfying the relationship of major axis r1 ≧ minor axis r2 ≧ thickness r3 . The toner according to any one of claims 12 to 16,
In the toner, a toner composition containing at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is crosslinked and / or elongated in an aqueous medium in the presence of resin fine particles. Toner.