JP4498153B2 - Full-color image forming device - Google Patents

Description

  The present invention relates to a toner used as a developer for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing, and the like, a manufacturing method thereof, and an image forming method using the toner. Further, the present invention relates to an electrophotographic toner used in an electrophotographic developing apparatus such as a copying machine, a laser printer, and a plain paper fax machine using a direct or indirect electrophotographic developing system, and an image forming method. Further, electrophotographic toner used in electrophotographic developing apparatuses such as full-color copying machines, full-color laser printers, full-color plain paper fax machines using a direct or indirect electrophotographic multicolor image developing system, and an image forming apparatus and an image forming method About.

  Conventionally, a latent image formed electrically or magnetically in an electrophotographic apparatus, an electrostatic recording apparatus or the like has been visualized with toner. For example, in electrophotography, an electrostatic charge image (latent image) is formed on a photoreceptor, and then the latent image is developed with toner to form a toner image. The toner image is usually transferred onto a transfer material such as paper, and then fixed onto the transfer material such as paper by a method such as heating. Further, the photosensitive member is cleaned by a cleaning member in order to form a latent image again. The toner used for developing an electrostatic image is generally colored particles containing a colorant, a charge control agent, and other additives in a toner binder. There is chemical toner.

  In recent years, there has been an increasing demand for chemical toners in order to obtain high-quality and high-quality images. The chemical toner manufacturing method can make the particle shape uniform, such as a spherical shape, and can have a small particle size and a sharp particle size distribution. In particular, by making the particle shape spherical, it is possible to improve transfer efficiency, reduce toner consumption, obtain a high-quality image with no missing image, and reduce running cost. If the transfer efficiency is very good, there is no need for a cleaning unit for removing untransferred toner from the photoreceptor or transfer medium, which has the advantages of reducing the size and cost of the equipment and eliminating waste toner. Because.

  At present, various chemical toner production methods have been devised. For example, a toner production method using a suspension polymerization method or an emulsion polymerization aggregation method is being studied. Patent Document 1 describes a method called volumetric shrinkage called a polymer dissolution suspension method. In this method, a toner material is dispersed and dissolved in a volatile solvent such as a low-boiling organic solvent, and this is emulsified and formed into droplets in an aqueous medium containing a dispersant, and then the volatile solvent is removed. Unlike the suspension polymerization method and emulsion polymerization aggregation method, this method is a versatile resin that can be used, and in particular, a polyester resin useful for a full color process that requires transparency and smoothness of the image area after fixing. It is excellent in that it can be used. However, many of the obtained toners have too high a sphericity, and although the transferability is good, the cleaning performance by the blade is extremely poor. If the cleaning performance becomes poor, residual toner remains on the photoconductor, and if it accumulates, it causes image smudges, and also contaminates the charging roller that contacts and charges the photoconductor, causing the original charge to occur. The ability will not be demonstrated. In addition, the fluidizing agent exposed on the surface is immediately embedded in the toner surface due to stress with the contact member in use, and the fluidity is impaired and toner replenishment property, developability, and charging property are deteriorated. To do.

  In Patent Documents 2 and 3, it is described that the cleaning ratio, developability, and image defect are improved by defining the number ratio of the toner having a nearly spherical shape and the number ratio of the amorphous toner. Describes that the black toner has an irregular shape rather than the other three colors, and the toners of the other three colors are made spherical, thereby achieving both transferability and image quality. However, small particle size toners and irregular toners have very strong adhesion to the photoreceptor and transfer efficiency is significantly deteriorated, so that recent small particle size toners cannot provide sufficient effects. In particular, the toner having a small particle diameter is likely to pass through the cleaning blade, and there is a problem that sufficient cleaning properties cannot be obtained.

  On the other hand, Patent Document 5 discloses that medium-sized inorganic fine particles having an average particle size of 20 to 40 μm are used in combination with an external additive in order to improve transferability, developability, and cleaning properties. Patent Documents 6 to 8 describe the use of inorganic fine particles having a large particle size in order to suppress the embedding of external additives in toner particles due to stress in the developing machine. Initially, good cleaning properties, transferability, and developability can be obtained, but the adhesion of inorganic fine particles to toner particles is uneven for each particle, and the inorganic fine particles are released from the toner particles over time. As a result, the inside of the developing machine and around the photoconductor are contaminated, and sufficient transferability and cleaning properties cannot be obtained.

  On the other hand, there is a problem that the transferability and fixability are lowered as the toner diameter is reduced, resulting in a poor image. In particular, in fixing, the fixing property of the halftone part is deteriorated. This is because the toner adhering to the halftone portion has a small amount of toner, so that the toner transferred to the concave portion on the transfer material has an extremely small amount of heat given from the fixing roller and is likely to cause offset development. Because.

In particular, in an image forming system using an intermediate transfer body, when toner transferability is low, a part of the toner image is not transferred, and voids and transfer dust occur. Furthermore, in the case of a color image, since one to three color toner layers are stacked and adhered on the intermediate transfer member, the image quality is greatly deteriorated due to transfer defects. In Patent Document 9, a pressure roller that presses the intermediate transfer belt from the inner peripheral surface toward the photosensitive drum is provided to improve the adhesion between the photosensitive drum and the intermediate transfer belt, and to increase the toner cohesion at the contact nip portion. And preventing transfer defects such as transfer dust. In Patent Document 10, the pressing force at the contact nip between the photosensitive member and the intermediate transfer belt, the linear speed ratio between the photosensitive member and the intermediate transfer belt, the surface resistance of the intermediate transfer belt, and the like are defined. Stipulates that the degree of aggregation and the bulk density are defined.
The toner transfer efficiency increases in proportion to the transfer bias applied to the nip portion between the photosensitive member and the intermediate transfer member, but discharge occurs when a certain electric field is reached (Paschen discharge). Efficiency decreases. When the first color toner layer, which is first transferred from the photosensitive member to the intermediate transfer member, is formed on the intermediate transfer member, the gap distance between the photosensitive member and the intermediate transfer member changes depending on the thickness of the toner layer. It is necessary to increase the transfer bias for transferring the second and subsequent toner layers by an electric field generated by the charged toner layer, which causes transfer dust. Further, since the toner layer thickness of the first color has irregularities depending on the image pattern, the transfer electric field is disturbed due to the non-uniform layer thickness, and the toner layer transferred from the second color onward is transferred. Chile is likely to occur.

JP-A-7-152202 JP-A-6-148926 Japanese Patent Laid-Open No. 6-148941 Japanese Patent No. 034359797 Japanese Patent Laid-Open No. 3-100161 Japanese Patent No. 033828013 JP-A-9-319134 Japanese Patent No. 03056122 JP 2000-22188 A JP 2001-209255 A

  An object of the present invention is a full-color image forming apparatus using an intermediate transfer member, which is excellent in transfer efficiency and does not cause transfer defects such as transfer dust and voids in character portions, even for images made of multi-color toners. An object is to provide an intermediate transfer member, an image forming apparatus, and a color toner kit.

  As a result of repeated studies on the above problems, the present inventors have defined the ratio of colorants such as pigments on the surface of color toners, particularly yellow toners (hereinafter referred to as surface colorant abundance ratios). It has been found that the above problems can be solved by using an image forming apparatus in which the toner is transferred onto the intermediate transfer member before the other color toners.

The amount of colorant present on and near the toner particle surface is an important factor that determines the electrical resistance at the surface of the toner. Therefore, by optimizing the surface colorant abundance ratio of the toner, it is possible to optimize the electrical resistance on the toner surface with little influence on color reproducibility, image density, or charging characteristics. It is important that the color toner of the first color transferred onto the intermediate transfer body is a toner whose surface electric resistance is adjusted to be the lowest, and it has been found that yellow toner is particularly optimal. The electric field formed from the first color toner layer formed on the intermediate transfer member has very little influence on the transfer electric field for transferring the second and subsequent color toner layers, and the first color toner layer. As compared with the above, it was found that the Coulomb repulsive force between the toner particles can be minimized by setting the surface electric resistance of the toner layers of the second and subsequent colors to be large.
As described above, an image having excellent transfer efficiency and free from transfer defects such as transfer dust is formed on the intermediate transfer member. In the present invention, when the multi-color multilayer toner layer formed on the intermediate transfer member is collectively transferred to the recording medium, the toner layer closest to the intermediate transfer member has a small electrostatic adhesion force. When the transfer bias is applied, the toner layer is efficiently transferred onto the recording medium.

  Furthermore, in the multicolor toner layer finally formed on the recording medium, if the abundance ratio of the colorant such as pigment on the surface of the lower toner layer is smaller than that of the upper toner layer, color reproducibility and color development At the same time, we were able to find that the properties were excellent. In general, since a colorant such as a pigment present on the toner surface inhibits low-temperature fixing, the smaller the amount of surface colorant present, the more the fixing property seems to work. When an unfixed image in which multicolored color toners are laminated is heat-fixed in the fixing section, the toner present in the lower layer is less likely to conduct heat and the fixability deteriorates. By reducing the toner, it is considered that the toners are melted with a small amount of heat, and as a result, the color reproducibility and color developability are improved.

That is, the problems of the present invention are solved by the following technical means and methods.
( 1 ) "Intermediate transfer member for sequentially transferring a toner image formed by developing an electrostatic latent image with a full-color image forming toner comprising at least a binder resin and a colorant, on the intermediate transfer member A full-color image forming apparatus having re-transfer means for re-transferring image toner onto a recording medium to form a toner image, wherein one of the full-color image forming toners is yellow toner, and the toner particles of the yellow toner The surface colorant abundance ratio (Y) of the toner is 1.4 to 2.0, the surface colorant abundance ratio of the other color toner particles is smaller than Y, and an intermediate transfer member of yellow toner A full-color image forming apparatus, wherein the transfer to the image forming toner is performed before the transfer of the other color-colored image forming toner ”,
( 2 ) “Of the multi-color layered toner transferred from the intermediate transfer member onto the recording medium, the yellow toner layer is above the image forming toner layer of other colors. “Full-color image forming apparatus according to item ( 1 )”,
( 3 ) “The image forming toner of other color other than the yellow toner contains at least a magenta toner and a cyan toner, and the surface colorant abundance ratio (M) of the magenta toner is 1.3 to 1.7. Item ( 1 ), wherein the cyan toner has a surface colorant abundance ratio (C) of 1.0 to 1.7, and M <Y or C <Y. Or the full color image forming apparatus according to item ( 2 ),
(4) "is transferred to the intermediate transfer member of the color toner, yellow toner, cyan toner, made in the order of the magenta toner, and, M <C <according to the first (3), characterized in that a Y Full-color image forming device ",
( 5 ) "The full-color image forming apparatus according to any one of ( 1 ) to ( 4 ), wherein the colorant of the yellow toner is an azo pigment or a quinacridone pigment" ,
( 6 ) "The above toner dissolves or disperses at least a compound having an active hydrogen group, a polymer having a site capable of reacting with the active hydrogen group, and a colorant in an organic solvent, and the solution or dispersion is dissolved in an aqueous system. The organic solvent is removed, washed and dried after being dispersed in a medium and reacting the compound having the active hydrogen group with the polymer having a site capable of reacting with the active hydrogen group or while reacting. A full-color image forming apparatus according to any one of ( 1 ) to ( 5 ), wherein the toner is a toner obtained by
( 7 ) “The volume average particle diameter (Dv) of the toner particles of the toner is 3.0 to 7.0 μm, and the ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) (Dv / Dn) is a full color image forming apparatus according to any one of ( 1 ) to ( 6 ), wherein the value is 1.25 or less,
( 8 ) "The full color image forming apparatus according to any one of ( 1 ) to ( 7 ) above, wherein an average circularity of the toner particles of the toner is 0.94 to 0.99". ,
( 9 ) “The recording medium on which the unfixed toner image has been formed, a heating body having a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film. The full-color image according to any one of ( 1 ) to ( 8 ), wherein the fixing unit having the above structure is configured to pass between the film and the pressure member to heat and fix the unfixed image. Image forming apparatus ",
( 10 ) “A heating roller made of a magnetic metal and heated by electromagnetic induction on the recording medium on which the unfixed toner image is formed, a fixing roller arranged in parallel with the heating roller, and the heating roller An endless belt-like toner heating medium that is stretched between the fixing roller and heated by the heating roller and rotated by these rollers, and is pressed against the fixing roller through the toner heating medium, The fixing means having a pressure roller that rotates in the forward direction to form a fixing nip portion with respect to the rotation method of the toner heating medium is passed between the toner heating medium and the pressure roller, and the undetermined The full-color image forming apparatus according to any one of ( 1 ) to ( 9 ), wherein the received image is heat-fixed.

  According to the present invention, in an intermediate transfer body and a full-color image forming apparatus using the intermediate transfer body, even an image made of multi-color toner is excellent in transfer efficiency and has transfer defects such as transfer dust and missing characters. An intermediate transfer member that does not occur, a full-color image forming apparatus, and a full-color toner kit are provided, and an extremely excellent effect is provided that a full-color image forming apparatus that provides a high-quality full-color image with excellent color developability is provided. The

Next, an embodiment of the present invention will be described.
Here, as for the toner, the manufacturing method and material of the developer used in the present invention, and the overall system relating to the electrophotographic process, known ones can be used if the conditions are satisfied.

<Surface colorant abundance ratio>
In the present invention, the surface colorant abundance ratio of the toner (hereinafter simply referred to as “surface colorant abundance ratio”) is the vicinity of the surface of the toner particles relative to the total amount of colorant contained in the toner particles (parts by weight of toner). The amount of colorant present (weight part near the toner surface, hereinafter simply referred to as “surface colorant abundance ratio”), provided that the pigment is uniformly dispersed in the toner particles. Set to 1. It can be said that the smaller the surface colorant abundance ratio is, the smaller the surface unevenness is, and the higher the surface coloring agent is, the higher the surface unevenness degree. Here, the vicinity of the surface of the toner in the present invention refers to a region of about 1.0 μm from the outermost surface of the toner particles to the inside of the toner particles.

  The amount of the colorant contained in the toner, for example, the amount of the pigment is such that the colorant such as a pigment is sufficiently dispersed in the binder resin at the time of toner production and can be sufficiently contained without loss in the toner particles. If it is a thing, it is easy to obtain | require from prescription amount. Further, even if the toner has an unknown colorant amount (hereinafter sometimes abbreviated as pigment amount), the pigment amount can be determined by various methods, and the method is not particularly limited. For example, a colorant such as a pigment (hereinafter sometimes abbreviated as “pigment”) is extracted with a suitable solvent such as THF (tetrahydrofuran) or chloroform, and the amount can be obtained. Furthermore, if there is a specific element in the pigment structure used, such as copper element in copper phthalocyanine, use an absolute quantitative value by ICP-MS (high frequency inductively coupled plasma mass spectrometry) or a calibration curve. Thus, it can be easily obtained by fluorescent X-ray analysis. The total colorant amount (pigment amount) in the examples of the present invention was calculated from this because the prescription amount was known.

The amount of the colorant present in the vicinity of the toner particle surface can be easily measured by FTIR (Fourier transform infrared spectroscopy) -ATR method (total reflection method). A detailed procedure example is described below.
In advance, a known amount of a colorant such as a pigment and a toner material such as a binder resin are sufficiently uniformly and finely dispersed in an agate mortar or the like, and a pellet sample is prepared using a molding machine. The above measurement is performed on the surface of the pellet sample, and an IR spectrum in which the X axis is wave number (cm ⁻¹ ) and the Y axis is absorbance is obtained. In the obtained spectrum, the peak intensity of a characteristic peak derived from the structure of the binder resin and not overlapping with the peak derived from the structure of other raw materials in the sample is defined as Pr. Similarly, the peak intensity of a characteristic peak derived from the structure of a colorant such as a pigment and not overlapping with the peak derived from the structure of another raw material in the sample is defined as Pp. There is no problem even if the absorbance of the peak is used as the peak intensity, but the valleys between the peaks before and after the peak to be measured are connected by a tangent, the tangent is used as a base line, the peak top (A), and the X-axis perpendicular passing through A It is preferable that the distance (AB) between the intersection points (B) of the baseline is the peak intensity. Moreover, as long as the conditions are satisfied, the peak intensity of any peak may be used and is not particularly limited. In the present invention, the peak intensity of the peak seen in the vicinity of 828 cm ⁻¹ originating from the out-of-plane skeleton vibration of the aromatic ring contained in the binder resin structure is Pr, and the aromatic ring C— contained in the pigment structure is C—. The peak intensity of the peak observed in the vicinity of 755 cm ⁻¹ that originates from the H out-of-plane variable vibration was defined as Pp. The depth of analysis by the ATR method is wavelength-dependent, and in the present invention, the wavelength of a peak derived from a colorant such as a pigment is 755 cm ⁻¹ , and is about 1.0 μm. Accordingly, the peak intensity ratio (P) derived from the colorant such as a pigment near the surface can be obtained from P = Pp / Pr. A calibration curve of the peak intensity ratio (P) and the colorant amount (pigment amount) near the surface was prepared by the above method.
Next, the IR spectrum of the surface of the toner made into a pellet sample by a molding machine is measured, and the peak intensity ratio (P) derived from the colorant (pigment) near the surface is obtained in the same manner as described above. The surface colorant abundance ratio can be determined. In the present invention, a pellet sample was prepared by applying a load of 6 t to 3 g of toner for 1 minute using a molding machine, and the surface was measured using an FTIR microscope ATR apparatus Spectrum One (manufactured by Perkin Elmer).

  In the present invention, the surface colorant abundance ratio (Y) of the yellow toner needs to be 1.4 to 2.0, preferably 1.5 to 1.8, more preferably 1.6 to 1. .8. If the value is smaller than this value, an appropriate amount of colorant (for example, pigment) for the present invention is not present in the vicinity of the surface, so that the electrical resistance of the toner surface increases and the effects of the invention cannot be obtained. On the other hand, if the value is larger than this value, the electrical resistance of the toner surface is extremely lowered, and sufficient charging characteristics cannot be obtained, and the colorant (for example, pigment) on the surface impairs the fixing property, resulting in cold offset and smear resistance. The colorability deteriorates and sufficient color reproducibility and color developability cannot be obtained.

  Any color toner other than the yellow toner can be used as long as the conditions are satisfied. However, it is common to use a magenta toner and a cyan toner from the viewpoint of color reproducibility of a full color image. preferable. The surface colorant abundance ratio (M) of the magenta toner is in an optimal range of 1.3 to 1.7, preferably 1.3 to 1.5. Further, the surface colorant abundance ratio (C) of the cyan toner is in an optimal range of 1.0 to 1.7, preferably 1.3 to 1.5. If it is smaller than these values, the electrical resistance and charge retention on the surface of the toner particles will increase as in the case of yellow toner, and it will be greatly affected by the electric field due to the toner layer on the intermediate transfer member, and will receive coulomb repulsion between the toner particles. It becomes easy to cause transfer dust. On the other hand, if the value is larger than these values, the charging characteristics, fixing properties, color reproducibility, and coloring properties are deteriorated as in the case of yellow toner. Further, satisfying the relationship of M <Y or C <Y is the most excellent in transferability, and can dramatically improve transfer dust and voids in character portions. Furthermore, when the color toner is transferred to the intermediate transfer member in the order of yellow toner, cyan toner and magenta toner, and when the condition of M <C <Y is satisfied, better transferability can be obtained. preferable.

<Volume average particle diameter / number average particle diameter>
In the toner of the present invention, the volume average particle diameter (Dv) of the toner particles is preferably 3.0 to 7.0 μm, and more preferably 3.5 to 6.0 μm. Further, the ratio (Dv / Dn) to the number average particle diameter (Dn) is preferably 1.25 or less, more preferably 1.10 to 1.20, and particularly preferably 1.10. It is preferable to be within the range of 1.15. Here, the volume average particle diameter is defined as Dv = [(Σ (nD ³ ) / Σn) ^1/3 (where n is the number of particles and D is the particle diameter). By setting the volume average particle diameter (Dv) and the ratio (Dv / Dn) of the toner of the present invention within the above ranges, a high-quality image excellent in fine line reproducibility and graininess can be obtained. In general, it is said that the smaller the particle diameter of the toner, the more advantageous it is for obtaining a high-resolution and high-quality image. Conversely, if the toner particle size is larger than this value, it will be difficult to obtain a high-resolution and high-quality image, and the toner particle size will be reduced when the toner in the developer is balanced. In many cases, the fluctuation becomes large. It was also clarified that the same applies when the volume average particle diameter / number average particle diameter (Dv / Dn) is too large. Furthermore, when (Dv / Dn) is too small, there are some aspects that are preferable from the viewpoint of stabilizing the behavior of the toner and uniformizing the charge amount, but there are cases where the toner is insufficiently charged and cleaning is also performed. It became clear that it might worsen sex.
The volume average particle size (Dv) and the ratio of the volume average particle size (Dv) to the number average particle size (Dn) (Dv / Dn) are measured by COULTER TA-II (manufactured by COULTER ELECTRONICS, INC), etc. Is automatically measured. The aperture diameter is 100 μm.

<Circularity and circularity distribution>
The toner in the present invention preferably has a specific shape and shape distribution. The toner particles preferably have an average circularity of 0.940 to 0.990, and an average circularity of 0.960 to 0.985. And particles having a circularity of less than 0.94 are more preferably 15% or less. The substantially spherical toner within the range of the average circularity is effective for forming a high-definition image having excellent transfer efficiency and reproducibility at an appropriate density. In addition, a good image with little transfer omission in a fine line image can be obtained. This is presumably because the toner surface is sufficiently smooth, the number of contact points with the image support is reduced, and the transfer failure of the toner to the transfer material is reduced. An irregularly shaped toner that is smaller than this range and too far away from the spherical shape tends to deteriorate the transferability, and conversely, if it is larger than this range and close to a sphere, the transferability is excellent. In a system that employs blade cleaning or the like, poor cleaning occurs on the photosensitive member and the transfer belt, causing stains on the image. For example, development or transfer with a low image area ratio results in a small amount of residual toner and poor cleaning is not a problem. However, when the image area ratio is high, such as a color photographic image, it is further The toner on which the transferred image is formed may be generated as a transfer residual toner on the photosensitive member, and if this is accumulated, the background stain of the image occurs. In addition, there is a problem that the charging roller or the like that contacts and charges the photosensitive member is contaminated, and the original charging ability is not exhibited.

  The average circularity can be measured using a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation). The measurement was adjusted to a 1% NaCl aqueous solution using primary sodium chloride and then passed through a 0.45 μm filter to 50 to 100 ml of a surfactant, preferably 0.1 to 5 ml of an alkylbenzene sulfonate as a dispersant. In addition, add 1-10 mg of sample. This was subjected to a dispersion treatment for 1 minute with an ultrasonic disperser and measured using a dispersion liquid in which the particle concentration was adjusted to 5000 to 15000 particles / μl. The diameter of a circle having the same area as a two-dimensional image captured by a CCD camera is assumed to be the equivalent circle diameter, and the equivalent circle diameter of 0.6 μm or more is effective from the accuracy of CCD pixels, and is used for calculating the average circularity. It was. The average circularity can be obtained by calculating the circularity of each particle, adding the circularity of each particle, and dividing by the total number of particles. The average circularity of each particle can be calculated by dividing the circumference of a circle having the same projected area as the particle image by the circumference of the particle projection image.

<Toner for electrostatic image development>
The toner production method and materials used in the present invention are not particularly limited, and any known ones can be used as long as the conditions are satisfied. However, from the viewpoint of low-temperature fixability, the binder resin used is preferably a polyester resin. In the present invention, the toner dissolves or disperses a compound having an active hydrogen group and a polymer having a site capable of reacting with the active hydrogen group, a release agent, and a colorant in at least an organic solvent, The dispersion is dispersed in an aqueous medium, and the organic solvent and the like are removed after reacting or reacting the compound having the active hydrogen group and the polymer having a site capable of reacting with the active hydrogen group. The toner for developing an electrostatic image characterized by being washed and dried was used. In the method for producing the polymerized toner, a polyester resin having high resin selectivity and high low-temperature fixability can be used. Moreover, it is excellent in granulation property and it is easy to control the particle size, particle size distribution, and shape. Furthermore, in the pigment dispersion step, the surface colorant abundance ratio can be easily controlled depending on the dispersion conditions, and therefore the toner produced by the above-described production method is preferable.

Below, the said manufacturing method and the material used are demonstrated.
[Organic solvent phase]
~ Organic solvent ~
The organic solvent used for forming the organic solvent phase in the present invention can be used without particular limitation as long as it can dissolve at least the functional group-containing polyester resin described later. In particular, since the organic solvent needs to be distilled off after the dispersion step of the organic solvent phase in the aqueous medium phase described later, the boiling point is less than 150 ° C. in order to facilitate the distillation step. It is preferable to use a volatile organic solvent.
Specific examples of the organic solvent used in the present invention include, for example, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, acetic acid. In addition to non-hydrophilic organic solvents such as methyl and ethyl acetate, water miscible organic solvents such as methyl ethyl ketone, acetone and tetrahydrofuran can be used, and these can be used alone or in combination of two or more. Among these, non-halogen solvents are particularly preferable, and methyl acetate and ethyl acetate are preferable from the viewpoint of safety. The amount of solvent used relative to 100 parts of the toner composition is usually 40 to 300 parts, preferably 60 to 140 parts, and more preferably 80 to 120 parts.

~ Colorant ~
As the colorant used in the present invention, known dyes and pigments can be used. For example, naphthol yellow S, hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher as yellow colorants, 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, etc., carbon black, nigrosine dye, iron black, bengara, red lead, lead red, cadmium red, Cadmium Mercury Red, Antimon Zhu, Permanentre 4R, Parared, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine 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 Rake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Rune, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, ultramarine, 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 go , Acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used.
Among these, regarding the yellow colorant, it is preferable to use an azo pigment or a quinacridone pigment because it is most excellent in maintaining the electric resistance of the toner surface appropriately.

  The amount of the colorant used is usually 1 to 15% by weight, preferably 3 to 10% by weight as the content in the toner of the present invention.

The colorant used in the present invention can also be used as a master batch combined with a resin.
As the binder resin (binder resin) kneaded together with the production of the master batch or the master batch, for example, in addition to the urea-modified polyester resin and the non-reactive polyester resin, polystyrene, poly p-chlorostyrene, polyvinyl toluene, etc. Styrene and its substituted polymers: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer Styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid Butyl copolymer, styrene α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinylmethylketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene -Styrene copolymers such as maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol Resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. These may be used alone or in combination of two or more.

This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force. At this time, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, which is a wet cake of colorant, is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. Since it can be used as it is, it is not necessary to dry it and it is preferably used.
For mixing and kneading, a high shearing dispersion device such as a three-roll mill is preferably used.
The colorant or masterbatch can be dissolved or dispersed in the organic solvent phase, but is not limited thereto.

-Functional group-containing polyester resin-
In the present invention, a functional group-containing polyester resin can be preferably used as the polymer having a site capable of reacting with an active hydrogen group. The functional group-containing polyester resin used in the present invention is dissolved in the organic solvent and, as will be described later, undergoes an extension reaction and / or a crosslinking reaction with an active hydrogen-containing compound to be described later in an aqueous medium, resulting in a higher molecular weight toner. It is a component that forms a binder.

Examples of the functional group-containing polyester resin include a polyester prepolymer having a functional group that reacts with active hydrogen such as an isocyanate group.
The polyester prepolymer preferably used in the present invention is the polyester prepolymer (A) having this isocyanate group. This polyester prepolymer (A) is produced by reacting a polyisocyanate (PIC) with a polyester having a polycondensate of a polyol (PO) and a polycarboxylic acid (PC) and having an active hydrogen group. 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. Examples of the polyol include diol (DIO) and trivalent or higher polyol (TO), and DIO alone or a mixture of DIO and a small amount of TO is preferable. Diols include alkylene glycols (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, etc.) Alkylene ether glycol (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenol (Bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the alicyclic diols (ethylene oxide, propylene oxide, butylene) Kisaido etc.) adducts; alkylene oxide (ethylene oxide of the bisphenols, propylene oxide, butylene oxide, etc.) adducts.
Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferable. Particularly preferred are alkylene oxide adducts of bisphenols and combinations thereof with alkylene glycols having 2 to 12 carbon atoms. Examples of the trihydric or higher polyol include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (trisphenol PA, Phenol novolac, cresol novolac, etc.); alkylene oxide adducts of the above trivalent polyphenols and the like. Examples of the polycarboxylic acid (PC) include dicarboxylic acid (DIC) and trivalent or higher polycarboxylic acid (TC), and DIC alone or a combination of DIC and a small amount of TC is preferable. Dicarboxylic acids 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, naphthalenedicarboxylic acid, etc.) ) And the like. Among these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polycarboxylic acid include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). The polycarboxylic acid may be subjected to a condensation reaction with a polyol as the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) described above.

  In order to prepare a polyester having an alcoholic hydroxyl group at the terminal by a polycondensation reaction, the polyol component and the polycarboxylic acid component are used in an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Usually, it is 2/1 to 1/1, preferably 1.5 / 1 to 1/1, and more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (PIC) used to prepare the polyester prepolymer (A) by reacting with the alcoholic hydroxyl group of the polyester include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-di-). Isocyanatomethyl caproate); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α ′) -Tetramethylxylylene diisocyanate, etc.); isocyanurates; those obtained by blocking the polyisocyanate with phenol derivatives, oximes, caprolactam, etc .; and Combinations of two or more of these and the like.

  The use ratio of the polyisocyanate is usually 5/1 to 1/1, preferably 4/1, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. To 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. If the equivalent ratio is too high, the low-temperature fixability of the obtained toner may be deteriorated. On the other hand, if the equivalent ratio is too low, the urea bond content in the reaction product with amines will be low, and the resulting toner will be resistant to hot offset. This is not preferable because the properties may deteriorate.

  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.

  In the present invention, as described above, the polyester prepolymer (A) is used by being dissolved in the organic solvent phase. The amount used and the amount of the polyester prepolymer (A) is 10 to 55% by weight as the content in the toner base. , Preferably 10 to 40% by weight, more preferably 15 to 30% by weight.

-Combination of non-reactive low molecular weight polyester-
In the present invention, as a toner binder component, not only the elongation reaction and / or crosslinking reaction product of the functional group-containing polyester resin and the active hydrogen compound described below, but also non-reactive polyester (PE) is contained in the organic solvent phase. It can be dissolved and used together. By using this PE in combination, the low-temperature fixability of the toner of the present invention and the glossiness when used in a full-color apparatus are improved, which is preferable to the case where the elongation reaction and / or crosslinking reaction product is used alone. Examples of PE include a polycondensate of a polyol and a polycarboxylic acid similar to the polyester used for the reaction with the polyisocyanate (PIC), and preferable ones are also the same as described above.

  Moreover, PE may be modified not only with unmodified polyester but also with a chemical bond other than a urea bond, for example, with a urethane bond. When formed into a toner, it is preferable in terms of low-temperature fixability and hot offset resistance that the elongation reaction and / or crosslinking reaction product and PE are at least partially compatible. Therefore, the polyester prepolymer (A) and PE preferably have similar compositions.

  In the present invention, when PE is contained in the organic solvent phase, the blending amount is 10/90 to 55/45, preferably 10/90 to 40 / as the weight ratio of the polyester prepolymer (A) and PE. 60, more preferably 15/85 to 30/70. When the weight ratio of the polyester prepolymer (A) is too low, hot offset resistance is deteriorated and it is difficult to achieve both heat-resistant storage stability and low-temperature fixability.

  In the present invention, the peak molecular weight of the weight average molecular weight measured by GPC (gel permeation chromatography) of PE is 5000 to 25000, preferably 8000 to 20000, and more preferably 13,000 to 18000. If the molecular weight is too low, the heat-resistant storage stability is deteriorated, whereas if it is too high, the low-temperature fixability is deteriorated.

  In the present invention, the acid value of PE is 15 to 45 mgKOH / g, preferably 20 to 35 mgKOH / g. Thus, by using a medium to high acid value PE resin, the low-temperature fixability can be improved without impairing the hot offset resistance. If the acid value is lower than this range, improvement in low-temperature fixability cannot be expected so much. On the other hand, if the acid value is too high, the reaction between the active hydrogen and the prepolymer tends to be inhibited, and the granulation property is lowered or the negative chargeability is reduced. It tends to be too strong and is not preferred.

Moreover, it is preferable that the hydroxyl value of PE is 5 or more, More preferably, it is 10-120, Most preferably, it is 20-80. If the hydroxyl value is too low, it is difficult to achieve both heat-resistant storage stability and low-temperature fixability.
The organic solvent phase may further contain a toner binder component other than those described above, for example, a conventionally known toner binder component such as a styrene resin, an acrylic resin, an epoxy resin, or a styrene-acrylate copolymer. Absent.

[Compound with active hydrogen]
As will be described later, the above-mentioned polyester prepolymer (A) having an isocyanate group has a higher molecular weight by an extension reaction and / or a crosslinking reaction with a compound having active hydrogen (active hydrogen-containing compound). .

  As the active hydrogen compound used in the present invention, amines (B) are preferably used, and a urea-modified polyester resin (UMPE) can be obtained by reaction with the isocyanate group of the polyester prepolymer (A). This has excellent performance as a toner binder.

  Examples of the amines (B) include diamine (B1), trivalent or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and amino acids (B1) to (B5). What blocked the group (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diamino). Cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. As (B6) which blocked the amino group of (B1) to (B5), a ketimine compound obtained from the amines of the above (B1) to (B5) and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), And oxazolidine compounds. Among these amines (B), preferred are (B1) and a combination of (B1) and a small amount of (B2).

  Furthermore, if necessary, the molecular weight of a modified polyester such as a urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The use ratio of the amines (B) is equivalent to the isocyanate group [NCO] in the prepolymer (A) having an isocyanate group and the amino group [NHx] (x is 1 or 2) in the amines (B). The ratio [NCO] / [NHx] is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. . If the equivalent ratio is too high or too low, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance of the resulting toner deteriorates.

  In the present invention, the polyester modified with a urea bond may contain a urethane bond (—O (CO) NH—) together with a urea bond (—NH (CO) NH—). The molar ratio between the urea bond content and 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.

-Properties of toner binder (binder resin)-
In the present invention, as described above, a urea-modified polyester resin obtained by reaction of the polyester prepolymer (A) and the amines (B) is used as a toner binder component, and a non-reactive polyester or the like is used. Other components (including a resin used in the preparation of the colorant master batch described later) are also used in combination.

  In the present invention, the glass transition point (Tg) of the toner binder is 50 to 70 ° C., preferably 55 to 65 ° C. If Tg is too low, the heat-resistant storage stability of the toner is deteriorated. Conversely, if Tg is too high, the low-temperature fixability becomes insufficient. In the dry toner of the present invention, the use of a urea-modified polyester resin or the like tends to have good heat-resistant storage stability even when the glass transition point is low as compared with known polyester toners. As the storage elastic modulus of the toner binder, the temperature (TG ′) at which the measurement frequency is 20 Hz becomes 1000 Pa is usually 100 ° C. or higher, preferably 110 to 200 ° C. When the TG ′ is too low, the hot offset resistance is deteriorated. As the viscosity of the toner binder, the temperature (Tη) at which the measurement frequency is 20 Hz becomes 100 Pa · s is usually 180 ° C. or less, preferably 90 to 160 ° C. If the Tη is too high, the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

[Aqueous medium phase]
~ Aqueous medium ~
In the present invention, the aqueous medium phase in which resin fine particles are dispersed can be preferably used. In the present invention, the aqueous medium for forming the aqueous medium phase by dispersing the resin fine particles described later in the aqueous medium phase to form the aqueous medium phase may be water alone, but a solvent miscible with water is used in combination. You can also. Examples of miscible solvents include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like. These can be used singly or in combination of two or more.

  Furthermore, in order to reduce the viscosity when the resin component contained in the organic solvent phase is dispersed in an aqueous medium, a solvent in which the polyester prepolymer (A) is soluble can be used in combination. The use of the solvent is preferable in that the particle size distribution of the toner particles becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. because it can be easily distilled off. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Examples thereof include methyl ethyl ketone and methyl isobutyl ketone, and these can be used singly or in combination of two or more. Particularly preferred are aromatic solvents such as toluene and xylene; halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride; and methyl acetate and ethyl acetate. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When the solvent is used, after the urea-modified polyester is formed, it is distilled off by heating under normal pressure or reduced pressure like other organic solvents.

~ Resin fine particles ~
In the present invention, the average particle size of the resin fine particles dispersed and used in the aqueous medium is 5 to 200 nm, preferably 20 to 300 nm. The resin fine particles function as an external additive that binds to the surface or surface layer portion of the droplet-like dispersed particles formed by dispersing the organic medium in the aqueous medium phase and coats the formed toner particles. It is an ingredient to do.

  The resin fine particles preferably have a glass transition point (Tg) of 40 to 90 ° C, and more preferably in the range of 50 to 70 ° C. If the Tg is too low, toner storage stability is deteriorated, and blocking occurs during storage and in the developing machine. On the other hand, if it is too high, the resin fine particles (B) inhibit the adhesiveness to the fixing paper, and the minimum fixing temperature rises, so that a sufficient fixing temperature range cannot be secured. Inconveniences such as being unable to be removed or being peeled off when the fixed image is rubbed occur.

  The weight average molecular weight is preferably 200,000 or less, more preferably 50,000 or less. The lower limit is usually 4000. If the weight average molecular weight is too high, the resin fine particles inhibit the adhesion to the fixing paper, and the minimum fixing temperature is increased.

As the resin fine particles, known resins can be used as long as they can form a dispersion in an aqueous medium, and may be thermoplastic resins or thermosetting resins. For example, vinyl resins, polyurethane resins, epoxy resins, Examples thereof include polyester resin, polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. These can be used singly or in combination of two or more. Among these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, or combinations thereof are preferable because an aqueous dispersion of fine spherical resin particles is easily obtained. Vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid-acrylic acid ester copolymers. Examples thereof include a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer.
The dispersion / blending amount of the resin fine particles in the aqueous medium is preferably 0.5 to 10 wt% with respect to the organic solvent phase. If it is not within this range, emulsification failure occurs and granulation cannot be performed. More preferably, it is 1 to 3 wt%.

  As described above, the resin fine particles are used for the purpose of controlling (aligning) the toner shape (circularity, particle size distribution, etc.), and are unevenly distributed on the surface of the toner base particles to be formed. The surface coverage by the resin fine particles with respect to the toner particles is preferably in the range of 1 to 90%, more preferably in the range of 5 to 80%. If the surface coverage is too high, the surface of the toner particles is almost completely covered with resin fine particles, and bleeding out of the release agent inside the toner particles to the toner particle surface is inhibited, and a releasing effect is obtained. As a result, the offset to the fixing roller occurs. Conversely, if the surface coverage is too low, the adhesion between the toner particles tends to work, and the toner tends to aggregate. Therefore, the fluidity of the toner is deteriorated, which is not preferable.

[Other ingredients]
~Release agent~
In the toner of the present invention, a release agent (wax) may be contained together with the binder resin and the colorant. Known waxes can be used, and examples thereof include polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sazol wax, etc.); carbonyl group-containing waxes, and the like. Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyhydric alcohol carboxylates (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1 , 18-octadecanediol distearate, etc.); polyvalent carboxylic esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyvalent amine carboxylic acid amides (ethylenediamine dibehenyl amide, etc.); polyvalent carboxylic acid amides (tri Meritic acid tristearyl amide, etc.); and dialkyl ketones (distearyl ketone, etc.). Among these carbonyl group-containing waxes, polyhydric alcohol carboxylic acid esters such as pentaerythritol tetrabehenate are preferable. The melting point of the wax used in the present invention is usually 40 to 160 ° C, preferably 50 to 100 ° C, and more preferably 50 to 70 ° C. A wax having a melting point that is too low adversely affects heat-resistant storage stability. Conversely, a wax having a melting point that is too high tends to cause a cold offset during fixing at a low temperature. The melt viscosity of the wax is preferably 5 to 1000 mPa · s, more preferably 10 to 100 mPa · s, as a measured value at a temperature 20 ° C. higher than the melting point. The wax having a too high melt viscosity has a poor effect of improving hot offset resistance and low-temperature fixability.

The amount of the wax used is usually 0 to 40% by weight, preferably 3 to 30% by weight as the content in the toner base of the present invention.
The wax can be dissolved or dispersed in the organic solvent phase, but is not limited thereto.

~ Charge control agent ~
The toner of the present invention may contain a charge control agent as necessary. Known charge control agents can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of a phenol-based condensate (manufactured by Orient Chemical Industry Co., Ltd.), TP-302 of a quaternary ammonium salt molybdenum complex, TP-415 (manufactured by Hodogaya Chemical Industry Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit), copper phthalocyanine, perylene, quinacridone, Zone-based pigment, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. In addition to causing a decrease, it is difficult to obtain the effect of the present invention due to the pigment existing in the vicinity of the toner surface. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch or resin, and of course, they may be added when dissolved or dispersed directly in an organic solvent. It is preferable to make it.

[Preparation of toner particles]
The toner particles in the present invention can be prepared by the following method.
-Dispersion and reaction of organic solvent phase-
As described above, in the toner particles, the organic solvent phase containing the polyester prepolymer (A) is dispersed in the aqueous medium phase together with the amines (B), and an elongation reaction and / or a crosslinking reaction is performed in the aqueous medium phase. To form a urea-modified polyester.

  In addition to the polyester prepolymer (A) and the non-reactive polyester, the colorant or colorant masterbatch, the release agent and the charge control agent may be dissolved or dispersed in advance in the organic solvent phase. Although most preferable for controlling the ratio, the colorant or the colorant masterbatch, the release agent and the charge control agent may be mixed when the organic solvent phase is dispersed in the aqueous medium. In the present invention, the colorant or the colorant master batch and the charge control agent may be added and blended after the toner particles are formed. For example, the charge control agent is preferably driven after the toner particles are formed, and after the toner particles not containing the colorant are formed, the colorant can be added by a known dyeing method.

  The surface colorant abundance ratio can be easily controlled in the above-described mixing / dispersing step of the colorant and the non-reactive polyester as the binder resin. In the present invention, a colorant masterbatch in which the colorant is sufficiently finely dispersed and a non-reactive polyester are mixed with a water-immiscible solvent such as ethyl acetate and a water-miscible solvent such as MEK (methyl ethyl ketone). For example, ethyl acetate: MEK = 4: 1). The dispersion method is not particularly limited, and for example, known methods 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. As the dispersion is more uniform and finely dispersed, the surface colorant abundance ratio tends to decrease. When the dispersion is not well done, the colorant can move relatively freely in the binder resin, and by moving to the water phase side by oil-water distribution at the stage of the emulsification process, It is considered that surface uneven distribution occurs. On the contrary, it is considered that when the dispersion is sufficiently performed, the filler effect by the colorant works, the structural viscosity of the binder resin increases, and it becomes difficult to move to the aqueous phase side during emulsification. It is also important to select the solvent to be mixed together, because the mobility of the colorant, for example, the pigment is greatly affected by the speed and amount of the solvent that moves to the aqueous phase side in the binder resin during emulsification. is there.

  Mixing of the polyester prepolymer (A) and the amines (B) (especially blocked ketimine) in the organic solvent phase may be performed before dispersion in the aqueous medium. When a blocked ketimine or the like is used as the amine (B), the block is removed in the aqueous medium, and the elongation and / or crosslinking reaction with the polyester prepolymer (A) can be performed. Further, the amine (B) may be added after the organic solvent phase is dispersed in the aqueous medium. When the amines (B) are added after the dispersion of the organic solvent phase, the reaction starts from the dispersed particle interface, urea-modified polyester is preferentially generated from the surface of the toner particles to be prepared, and a concentration gradient may be provided inside the particles. it can.

Examples of a method for stably forming a dispersion of an organic solvent phase and an amine (B) in an aqueous medium include a method in which a shearing force is applied and dispersed.
The dispersion method is not particularly limited, and known methods 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. The particle size of the dispersion is preferably 2 to 20 μm, and for this purpose, it is preferable to use a high-speed shearing method. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30,000 rpm, preferably 5000 to 20,000 rpm. The dispersion time depends on the processing amount and is not particularly limited. However, in the case of a batch method, it is usually about 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. It is preferable that the temperature during dispersion is high because the viscosity of the polyester prepolymer (A) and the like contained in the organic solvent dispersed phase can be lowered and the dispersion is easy.

  The usage-amount of the aqueous medium (except resin fine particles) with respect to 100 parts of solid content contained in an organic solvent phase is 50-2000 weight part normally, Preferably it is 100-1000 weight part. If the amount used is too small, the dispersed state of the organic solvent phase becomes non-uniform, and toner particles having a predetermined particle diameter cannot be obtained. On the other hand, if it is too much, it is not particularly effective, disadvantageous in terms of cost, and not economical. Moreover, a dispersing agent can also be used as needed. The use of a dispersant is preferable in that the particle size distribution becomes sharp and the dispersion is stable.

  When the dispersant is used, examples of the dispersant include anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters; alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, Cationic surfactants of amine salt type such as imidazoline, and quaternary ammonium salt type such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride Nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; amphoteric boundaries such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine Active agents.

  Further, by using a surfactant having a fluoroalkyl group, a dispersion effect can be exhibited with a very small amount of use. Preferred examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms and a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 3- [ω-fluoroalkyl ( C6-C11) oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11- C20) Carboxylic acid and its metal salt, Perfluoroalkylcarboxylic acid (C7 to C13) and its metal salt, Perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, Perfluorooctanesulfonic acid diethanolamide, N-propyl -N- (2hydroxy Ciethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphoric acid Examples include esters. As a trade name, 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 (Daikin Kogyo Co., Ltd.); Megafac F-l10, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.); 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). Further, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary amine, secondary amine or secondary amine acid having a fluoroalkyl group, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, etc. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.); Unidyne DS-202 (Daikin Kogyo Co., Ltd.); Megafuck F-150, F-824 (Dainippon Ink, Inc.) Xetop EF-132 (manufactured by Tochem Products); Footage F-300 (manufactured by Neos) and the like. Further, calcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can also be used as inorganic compound-based dispersants that are hardly soluble in water. Further, the dispersed droplets may be stabilized using a polymer protective colloid. For example, acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride; (meth) acrylic monomer containing hydroxyl group Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-acrylate Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N-methyl Roll acrylamide, N-methylol methacrylamide, etc .; Vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc .; Esters of compounds containing vinyl alcohol and carboxyl groups, such as, for example, Pinyl acetate, vinyl propionate, vinyl butyrate, etc .; acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds; acid chlorides such as acrylic acid chloride, methacrylic acid chloride; pinylpyridine, vinylpyrrolidone, vinylimidazole, ethyleneimine Homopolymers or copolymers of vinyl monomers such as those having a nitrogen atom such as the above or a heterocyclic ring thereof can be used. Also, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxy Polyoxyethylenes such as ethylene stearyl phenyl ester and polyoxyethylene nonylphenyl ester; celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can also be used. In addition, when using an acid or alkali soluble material such as calcium phosphate salt as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and then washing with water. To do. In addition, it can be removed by an operation such as enzymatic degradation. When a dispersant is used, the dispersant can remain on the surface of the toner particles, but the elongation and / or crosslinking reaction between the polyester prepolymer (A) and the amines (B) is completed. Thereafter, removal by washing or the like is preferable from the viewpoint of the charging characteristics of the toner of the present invention.

~ Toner particle molding ~
In order to remove the organic solvent and the like from the obtained dispersion, a method of gradually elevating the temperature of the entire system and completely removing the organic solvent in the droplets can be employed. Alternatively, the dispersion liquid can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner particles, and the aqueous dispersant can be removed by evaporation together. As the dry atmosphere, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, particularly various air streams heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient target quality can be obtained by short-time treatment using a spray dryer, belt dryer, rotary kiln or the like.

~ Application of external additives ~
The toner particles (base material) obtained by the operations and processes as described above are further treated on the surface with an external additive to obtain the toner of the present invention with improved fluidity, developability, chargeability and the like. . As the external additive for assisting, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and particularly preferably 5 nm to 500 nm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight, particularly 0.01 to 2.0% by weight, based on the toner particles.

  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, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. These can be used singly or in combination of two or more.

  Other than inorganic fine particles, polymer fine particles such as polystyrene, methacrylic ester-based or acrylate-based copolymers obtained by soap-free emulsion polymerization suspension polymerization or dispersion polymerization, silicone resins, benzoguanamine resins, polyamides Polymer particles such as a polycondensation system such as a thermosetting resin can be used.

  The external additive used for improving fluidization and the like is subjected to surface treatment in advance to make it hydrophobic, thereby preventing deterioration of the toner flow characteristics, charging characteristics and the like even under high humidity. be able to. Examples of the surface treatment agent include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils. Etc. are preferably exemplified.

  Further, for the purpose of improving the cleaning property when removing the developer after transfer remaining on the photosensitive member and the primary transfer medium, toner particles (base material) are made of, for example, zinc stearate, calcium stearate, stearic acid, etc. Fatty acid metal salt; for example, it can be treated with polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles used preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

<Two-component developer>
When the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 1 to 10 wt. Part is preferable, and the range of 5 to 10 parts by weight is more preferable.

As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used.
Examples of the coating material for the magnetic carrier include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin; urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins; polystyrene resins such as polystyrene resins and styrene acrylic copolymer resins; Halogenated olefin resins such as vinyl chloride; polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin: polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexa Fluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride Fluoro such as terpolymers of emission and non-fluoride monomers including, and silicone resins.

Moreover, you may make conductive powder etc. contain in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier, or a non-magnetic toner.

<Image forming apparatus>
Hereinafter, an image forming apparatus using the electrophotographic toner of the present invention or a two-component developer composed of the toner and a carrier will be described.

-Intermediate transfer member-
An embodiment of an intermediate transfer member of the transfer system in the present invention will be described. FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment. Around a photosensitive drum (hereinafter referred to as a photosensitive member) (10) as an image carrier, a charging roller (20) as a charging means, an exposure means (30), a cleaning means (60) having a cleaning blade, a static elimination A neutralizing lamp (70) as a means, a developing means (40), and an intermediate transfer member (50) for intermediate transfer are disposed. The intermediate transfer member (50) is suspended by a plurality of suspension rollers (51) (51), and is configured to run endlessly in the direction of the arrow by a driving means such as a motor (not shown). A part of the suspension roller (51) also serves as a transfer bias roller for supplying a transfer bias to the intermediate transfer member (50), and a predetermined transfer bias voltage is applied from a power source (not shown). A cleaning means (90) having a cleaning blade for the intermediate transfer member (50) is also provided. Further, a transfer roller (80) is disposed as a transfer means for transferring the developed image onto the transfer paper (100) as the final transfer material, facing the intermediate transfer body (50), and the transfer roller (80). Is supplied with a transfer bias by a power supply device (not shown). Around the intermediate transfer member (50), a corona charger (52) is provided as a charge applying unit.

  The developing means (40) includes a developing belt (41) as a developer carrying member, a black (hereinafter referred to as Bk) developing unit (45K) and yellow (hereinafter referred to as Yk) provided around the developing belt (41). Development unit (45Y), magenta (hereinafter referred to as magenta) development unit (45M), and cyan (hereinafter referred to as C) development unit (45C). Further, the developing belt (41) is stretched between a plurality of belt rollers, and is configured to run endlessly in a direction of an arrow by a driving unit such as a motor (not shown), and a contact portion with the photoreceptor (10). Then, it moves at almost the same speed as the photoconductor (10).

  Since the configuration of each developing unit is common, the following description will be given only for the Bk developing unit (45K), and the other developing units (45Y), (45M), and (45C) will be described in the figure with the Bk developing unit ( (Y), (M), and (C) are added to the parts corresponding to those in 45K) after the numbers given to those in the unit, and description thereof is omitted. The developing unit (45K) is arranged so that a developer container (42K) containing a two-component developer containing toner particles and a carrier component and a lower part are buried in the developer in the developer container (42K). And a conveying roller (44K) that thins the developer supplied from the supplying roller (43K) and conveys it to the developing belt 41. The transport roller (44K) has conductivity, and a predetermined bias is applied from a power source (not shown).

  In addition to the apparatus configuration shown in FIG. 1, the apparatus configuration of the copying machine according to the present embodiment includes a developing unit (45) for each color as shown in FIG. 2 around the photoreceptor (10). A device configuration may be provided.

  Next, the operation of the copying machine according to the present embodiment will be described. In FIG. 1, the photosensitive member (10) is uniformly charged by a charging roller (20) as a charging unit while being driven to rotate in the direction of an arrow, and then reflected light from a document by an exposure unit (30) by an optical system (not shown). An electrostatic charge image is formed on the photoconductor (10) by image projection. This electrostatic charge image is developed by the developing means (40) to form a toner image as a visible image. The developer thin layer on the developing belt (41) is peeled off from the belt (41) in a thin layer state by contact with the photoreceptor in the developing region, and a latent image is formed on the photoreceptor (10). Transition to the part. The toner image developed by the developing means (40) is transferred to the intermediate transfer member (50) at a contact portion (primary transfer region) between the photosensitive member (10) and the intermediate transfer member (50) moving at a constant speed. (Primary transfer or intermediate transfer). When transferring three or four colors to be superimposed, this process is repeated for each color to form a color image on the intermediate transfer member (50).

  The corona charger (52) for applying an electric charge to the superimposed toner image on the intermediate transfer member (50) is disposed between the photosensitive member (10) and the intermediate member in the rotation direction of the intermediate transfer member (50). It is installed on the downstream side of the contact facing portion with the transfer body (50) and on the upstream side of the contact facing portion between the intermediate transfer body (50) and the transfer paper (100). The corona charger (52) gives the image-like toner layer a true charge having the same polarity as the charge polarity of the toner particles forming the image-like toner layer, which is good for the transfer paper (100). Sufficient charge is applied to the image-wise toner layer for proper transfer. After the image-like toner layer is charged by the corona charger (52), the transfer paper (100) conveyed in the direction of the arrow from a paper supply unit (not shown) by a transfer bias from the transfer roller (80). It is transferred onto the top (secondary transfer or retransfer). Thereafter, the transfer paper (100) onto which the toner image has been transferred is separated from the photoconductor (10) by a separation means (not shown), and after being fixed by a fixing means (not shown), the transfer paper (100) is discharged from the apparatus. On the other hand, the untransferred toner is collected and removed from the photoreceptor (10) after the transfer by the cleaning means (60), and the residual charge is discharged by the charge removal lamp (70) in preparation for the next charging.

As described above, the static friction coefficient of the intermediate transfer member is preferably 0.1 to 0.6, and more preferably 0.3 to 0.5. The volume resistance of the intermediate transfer member is preferably from several Ωcm to 10 ³ Ωcm. When the volume resistance is set to several Ωcm or more and 10 ³ Ωcm or less, the intermediate transfer member itself is prevented from being charged, and the charge imparted by the charge imparting means hardly remains on the intermediate transfer member. Transfer unevenness can be prevented. Further, it is possible to easily apply a transfer bias at the time of secondary transfer.

The material of the intermediate transfer member is not particularly limited, and all known materials can be used. An example is shown below.
(1) A material having a high Young's modulus (tensile modulus) is used as a single-layer belt. PC (polycarbonate), PVDF (polyvinylidene fluoride), PAT (polyalkylene terephthalate), PC (polycarbonate) / PAT ( Polyalkylene terephthalate) blend material, ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT blend material, carbon black dispersed thermosetting polyimide, and the like. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation with respect to stress during image formation is small, and registration is not likely to occur particularly during color image formation.
(2) A belt having a two- to three-layer structure in which a belt having a high Young's modulus is used as a base layer and a surface layer or an intermediate layer is provided on the outer periphery thereof. Therefore, the line image has a performance capable of preventing the line image from being lost.
(3) Belts having a relatively low Young's modulus using rubber and elastomer, and these belts have the advantage that line images are hardly lost due to their softness. In addition, the width of the belt is made larger than that of the drive roll and the tension roll, and the elasticity of the belt ear protruding from the roll is used to prevent meandering, so that low cost can be realized without the need for ribs or meandering prevention devices. .

  Conventionally, a fluorine-based resin, a polycarbonate resin, a polyimide resin, or the like has been used for the intermediate transfer belt, but in recent years, an elastic belt in which the entire belt layer or a part of the belt is used as an elastic member has been used. The transfer of a color image using a resin belt has the following problems.

  A color image is usually formed with four colored toners. On one color image, toner layers of 1 to 4 layers are formed. The toner layer receives pressure by passing through the primary transfer (intermediate transfer from the photoconductor to the intermediate transfer belt) and the secondary transfer (retransfer from the intermediate transfer belt to the sheet), and the cohesive force between the toners is high. Become. When the cohesive force between the toners increases, the phenomenon of missing characters in the characters and missing edges in the solid portion image tends to occur. Since the resin belt has a high hardness and does not deform according to the toner layer, the toner layer is easily compressed, and the character dropout phenomenon is likely to occur.

  Recently, there is an increasing demand for forming full-color images on various papers, for example, Japanese paper, intentionally irregularities, and forming images on paper. However, a paper with poor smoothness is liable to generate toner and voids at the time of transfer, and transfer loss is likely to occur. When the transfer pressure at the secondary transfer portion is increased to improve the adhesion, the condensing power of the toner layer is increased, and the above-described character void is generated.

  The elastic belt is used for the following purposes. The elastic belt is deformed corresponding to the toner layer and the paper having poor smoothness at the transfer portion. In other words, since the elastic belt deforms following local irregularities, it is possible to obtain a good adhesion without excessively increasing the transfer pressure with respect to the toner layer, and a paper with poor flatness that has no void in characters. In contrast, a transfer image with excellent uniformity can be obtained.

  The elastic belt resin is polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer. Styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (for example, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene- Octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (for example, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid). Acid phenyl copolymer, etc.), styrene -Styrenic resins (monopolymer or copolymer containing styrene or styrene-substituted product) such as methyl α-chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, methyl methacrylate resin, methacrylic acid Butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (for example, silicone-modified acrylic resin, vinyl chloride resin-modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, Vinyl chloride-vinyl acetate copolymer, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silica One or a combination of two or more selected from the group consisting of carbon resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins, polyamide resins and modified polyphenylene oxide resins can be used. . However, it is a matter of course that the material is not limited to the above materials.

  Elastic rubbers and elastomers include butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene ter Polymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluororubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber , Selected from the group consisting of thermoplastic elastomers (for example, polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester, fluororesin) It is possible to use one kind or two or more kinds of combinations that. However, it is a matter of course that the material is not limited to the above materials.

  There are no particular restrictions on the conductive agent for adjusting the resistance value. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite Conductive metal oxides such as oxides (ATO) and indium oxide-tin oxide composite oxides (ITO), and conductive metal oxides are coated with insulating fine particles such as barium sulfate, magnesium silicate and calcium carbonate But you can. Of course, the conductive agent is not limited thereto.

  The surface layer material and the surface layer are required to prevent contamination of the photoconductor by the elastic material, reduce the surface friction resistance to the transfer belt surface, reduce the adhesion of the toner, and improve the cleaning property and the secondary transfer property. . For example, materials that use one or a combination of two or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. These powders and particles can be used by dispersing one type, two or more types, or a combination of particles having different particle sizes. Further, it is also possible to use a material having a reduced surface energy by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

  The belt manufacturing method is not limited. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which a liquid paint is sprayed to form a film, and a cylindrical mold are used. Examples include, but are not limited to, a dipping method in which the material is dipped in a solution of the material, a casting method in which it is injected into the inner mold and the outer mold, a method in which a compound is wound around a cylindrical mold and vulcanized and polished. In general, a belt is manufactured by combining a plurality of manufacturing methods.

  As a method for preventing elongation as an elastic belt, there are a method of forming a rubber layer in a core resin layer with little elongation, a method of putting a material for preventing elongation in a core layer, and the like, but the method is limited to a specific manufacturing method is not.

  The material constituting the core layer for preventing elongation includes, for example, natural fibers such as cotton and silk; polyester fibers, nylon fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, One or two selected from the group consisting of synthetic fibers such as polyurethane fibers, polyacetal fibers, polyfluoroethylene fibers, and phenol fibers; inorganic fibers such as carbon fibers, glass fibers, and boron fibers; and metal fibers such as iron fibers and copper fibers A combination of two or more species is used to form a woven fabric or a yarn. Of course, the material is not limited to the above.

  The yarn may be twisted in any manner, such as one or a plurality of filaments twisted, a single twisted yarn, various twisted yarns, a double yarn or the like. Further, for example, fibers of a material selected from the above material group may be blended. Of course, the yarn can be used after being subjected to an appropriate conductive treatment. On the other hand, any woven fabric such as knitted fabric can be used as the woven fabric. Of course, a woven fabric with interweaving can also be used, and naturally conductive treatment can be performed.

  The production method for providing the core layer is not particularly limited. For example, a method of providing a coating layer on a woven fabric woven in a cylindrical shape on a mold or the like, and a liquid woven woven fabric in a cylindrical shape. Examples thereof include a method in which a coating layer is provided on one or both sides of the core layer by dipping in rubber or the like, and a method in which a yarn is spirally wound around a mold or the like at an arbitrary pitch and a coating layer is provided thereon.

  The thickness of the elastic layer depends on the hardness of the elastic layer, but if it is too thick, the surface expands and contracts and cracks are likely to occur in the surface layer. Also, it is not preferable that the thickness is too large (approximately 1 mm or more) because the amount of expansion and contraction becomes large and the image is stretched.

-Fixing means (surf fixing device)-
As the fixing means (fixing device) in the present invention, a so-called surf fixing device that rotates and fixes a fixing film as shown in FIG. 3 was used. In detail, the fixing film is an endless belt-like heat-resistant film, and is fixed and supported by a driving roller, a driven roller, and a heater support provided below the rollers, which are support rotating members of the film. The heating body is arranged in a suspended manner.

The driven roller also serves as a tension roller for the fixing film, and the fixing film is rotationally driven in the clockwise direction by the rotational driving of the driving roller in the clockwise direction in the drawing. This rotational driving speed is adjusted to a speed at which the transfer material and the fixing film are equal in the fixing nip region L where the pressure roller and the fixing film are in contact with each other.
Here, the pressure roller is a roller having a rubber elastic layer having good releasability, such as silicon rubber, and a contact pressure of 4 to 10 kg of total pressure against the fixing nip region L while rotating counterclockwise. With pressure contact.

  The fixing film preferably has excellent heat resistance, releasability and durability, and a thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used. For example, at least an image of a single layer film of a heat-resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), or a composite layer film, for example, a 20 μm thick film The contact surface is coated with a release coating layer of PTFE (tetrafluoroethylene resin), PFA or other fluororesin added with a conductive material to a thickness of 10 μm, or an elastic layer such as fluororubber or silicon rubber. It is a thing.

In FIG. 3, the heating body of the present embodiment is composed of a flat substrate and a fixing heater, and the flat substrate is made of a material having high thermal conductivity and high electrical resistivity, such as alumina, and is in contact with the fixing film. Has a fixing heater formed of a resistance heating element in the longitudinal direction. Such a fixing heater is formed by coating an electric resistance material such as Ag / Pd or Ta ₂ N in a linear or belt shape by screen printing or the like. In addition, electrodes (not shown) are formed at both ends of the fixing heater, and the resistance heating element generates heat when energized between the electrodes. Furthermore, a fixing temperature sensor constituted by a thermistor is provided on the surface of the substrate opposite to the surface provided with the fixing heater.

The temperature information of the substrate detected by the fixing temperature sensor is sent to a control unit (not shown), and the amount of electric power supplied to the fixing heater is controlled by the control unit, and the heating body is controlled to a predetermined temperature.
The fixing means (apparatus) used in the present invention is not limited to the surf fixing apparatus as described above, but a fixing means that is excellent in color reproducibility and color developability, is efficient and can shorten the rise time is used. Therefore, it is preferable to use a surf fixing device.

-Fixing means (electromagnetic induction heating method (IH fixing device))-
As shown in FIG. 4A, the fixing means in the present invention generates Joule heat by an eddy current generated in a magnetic metal member by an alternating magnetic field as shown in FIG. A so-called electromagnetic induction heating type fixing device (IH fixing device) is used.

  The fixing unit shown in FIG. 4A includes a heating roller (1) heated by electromagnetic induction of the induction heating unit (6), a fixing roller (2) arranged in parallel with the heating roller (1), and a heating unit. An endless belt-like heat resistance stretched between the roller (1) and the fixing roller (2), heated by the heating roller (1), and rotated in the direction of the arrow (A) by at least one of these rollers rotating. A belt (toner heating medium) (3) and a pressure roller (4) which is pressed against the fixing roller (2) via the belt (3) and rotates in the forward direction with respect to the belt (3). ing. The heating roller (1) is made of a hollow cylindrical magnetic metal member such as iron, cobalt, nickel, or an alloy of these metals, and has a low heat capacity and a high temperature rise. The fixing roller (2) includes, for example, a metal core (2a) made of stainless steel or the like, and an elastic member (2b) covered with a core metal (2a) in a solid or foamed heat-resistant silicone rubber. Consists of. In order to form a contact portion having a predetermined width between the pressure roller (4) and the fixing roller (2) by the pressing force from the pressure roller (4), the outer diameter is larger than that of the heating roller (1). is doing. With this configuration, the heat capacity of the heating roller (1) is smaller than the heat capacity of the fixing roller (2), and the heating roller (1) is rapidly heated to shorten the warm-up time. The belt (3) stretched between the heating roller (1) and the fixing roller (2) is heated at the contact portion (W1) with the heating roller (1) heated by the induction heating means (6). The inner surface of the belt (3) is continuously heated by the rotation of the rollers (1) and (2). As a result, the entire belt is heated. The pressure roller (4) includes, for example, a metal core (4a) made of a metal cylindrical member having high thermal conductivity such as copper or aluminum, and heat resistance and toner separation provided on the surface of the metal core (4a). It is comprised from the highly elastic elastic member (4b). In addition to the above metal, SUS may be used for the core metal (4a). The pressure roller (4) presses the fixing roller (2) via the belt (3) to form a fixing nip (N). In this embodiment, the hardness of the pressure roller (4) Is made harder than the fixing roller (2), so that the pressure roller (4) bites into the fixing roller (2) (and the belt (3)), and the recording material (11) is pressed by this biting. Since the roller (4) has a circumferential shape on the surface, the recording material (11) is easily separated from the surface of the belt (3).

  Induction heating means (6) for heating the heating roller (1) by electromagnetic induction, as shown in FIGS. 4 (a) and 4 (b) A and B, an excitation coil (7) as magnetic field generation means, And a coil guide plate (8) around which the exciting coil (7) is wound. The coil guide plate (8) has a semi-cylindrical shape arranged close to the outer peripheral surface of the heating roller (1), and the excitation coil (7) is a single long excitation as shown in FIG. 4 (b) B. A coil wire is alternately wound along the coil guide plate (8) in the axial direction of the heating roller (1). The exciting coil (7) has an oscillation circuit connected to a drive power supply (not shown) whose frequency is variable. Outside the excitation coil (7), a semi-cylindrical excitation coil core (9) made of a ferromagnetic material such as ferrite is fixed to the excitation coil core support member (12) and is arranged close to the excitation coil (7). Yes. In this embodiment, the exciting coil core (9) having a relative permeability of 2500 is used. A high frequency alternating current of 10 kHz to 1 MHz, preferably a high frequency alternating current of 20 kHz to 800 kHz is supplied to the exciting coil (7) from the driving power source, thereby generating an alternating magnetic field. The alternating magnetic field acts on the heat generating layer of the heating roller (1) and the belt (3) in the contact area (W1) between the heating roller (1) and the heat-resistant belt (3) and in the vicinity thereof. Then, the eddy current I flows in the direction B that prevents the change of the alternating magnetic field. This eddy current I generates Joule heat corresponding to the resistance of the heat generating layer of the heating roller (1) and the belt (3), and heats mainly in the contact area between the heating roller (1) and the belt (3) and its vicinity. The roller (1) and the belt (3) having the heat generating layer are heated by electromagnetic induction.

The belt (3) heated in this way is sent from a thermosensitive element such as a thermistor arranged in contact with the inner surface of the belt (3) in the vicinity of the entrance side of the fixing nip (N). The belt inner surface temperature is detected by the temperature detecting means (5).
Of course, the fixing means used in the present invention is not limited to the above-described IH fixing apparatus, but a high-quality image having particularly excellent color reproducibility and color developability can be obtained, and a heat roller system can be used. It is preferable to use an IH fixing device because the heat transfer efficiency is higher than that of the fixing device, the warm-up time can be shortened, and an image forming apparatus using fixing means capable of quick start and energy saving can be obtained.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited only to these examples. In the following examples, “parts” and “%” are based on weight unless otherwise specified.

<Creation 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 7 parts by weight of the 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>
In the toners obtained in the following examples and comparative examples, the four color developing sections sequentially develop the developer on one photosensitive member for each color, and the intermediate transfer member sequentially includes black toner, yellow toner, cyan toner, and magenta toner. The evaluation machine A is a full-color laser printer (PRTER650 modified machine manufactured by Ricoh) that is adjusted by providing an oil-less surf fixing device. The evaluation machine B is the same as the evaluation machine A except that the black toner, magenta toner, cyan toner, and yellow toner are sequentially transferred to the intermediate transfer member in this order. Evaluation was performed by an evaluation machine C improved to an oil-less IH fixing device.

<Evaluation items>
The following items were evaluated for the performance of the toners obtained in the examples and comparative examples.
(1) Image granularity / sharpness Using the evaluation machines A, B, and C, 10,000 full-color photographic images were output in full color mode, and the degree of granularity and sharpness was visually evaluated. It is evaluated in five stages of ranks 1 to 5, rank 5 is the best, and rank 1 is the worst. In Table 2, the degree is 5 in the case of offset printing, 4 if slightly better than the conventional electrophotographic image, 3 in the case of the conventional electrophotographic image, and more than the conventional electrophotographic image. When it was slightly worse, it was displayed as 2, and when it was considerably worse than the conventional electrophotographic image, it was displayed as 1.
(2) Fine line reproducibility Using valuation machines A, B, and C, after running 30,000 full color image charts with 50% image area in full color mode, a 600 dpi full color thin line image is printed on Ricoh type 6000 paper. The degree of bleeding of the thin line was compared with that of the step sample. Evaluation is made in five stages of ranks 1 to 5, rank 5 is the best in fine line reproducibility, and rank 1 is the worst. In Table 2, the degree is 5 in the case of offset printing, 4 if slightly better than the conventional electrophotographic image, 3 in the case of the conventional electrophotographic image, and more than the conventional electrophotographic image. When it was slightly worse, it was displayed as 2, and when it was considerably worse than the conventional electrophotographic image, it was displayed as 1.
(3) Missing character part Using evaluation machines A, B, and C, after running 30,000 full color image charts with 50% image area in full color mode, the full color character part image is type DX made by Ricoh. The toner non-transfer frequency at which the inside of the line image in the character portion is lost is compared with the stage sample and evaluated in five stages of ranks 1 to 5. In Table 2, it is 5 when no voids are observed, 4 when slight voids are observed, 3 when conventional electrophotographic images are observed, and 2 when many voids are observed. , And when a hollow was observed with considerable frequency, it was indicated as 1.
(4) Transfer dust After running 30,000 full color image charts with 50% image area in full color mode using evaluation machines A, B, and C, a 600 dpi full color thin line image is output to Ricoh type 6000 paper. The frequency and extent of transcription dust were compared with the stage samples. Evaluation is made in five stages of ranks 1 to 5, rank 5 is the best in fine line reproducibility, and rank 1 is the worst. In Table 2, when the transfer dust is not seen at all, it is 5; when the very slight transfer dust is seen at a low frequency, it is 4; In many cases, “2” was indicated when the degree was poor, and “1” was indicated when the transfer dust was quite frequent and the degree was also quite bad.
(5) Transfer rate Using evaluation machines A, B, and C, two-color superimposed solid images (30 mm × 80 mm) of red (R), green (G), and blue (B) are each printed on the photoconductor. .80 ± 0.1 mg / cm ² (0.40 ± 0.05 mg / cm ^{2 for} each toner color) with an attached amount of toner, transferred to Ricoh type 6200 paper, immediately after transfer of the second color toner The transfer residual toner on the photoconductor was copied onto a pre-weighed tape, and the amount of transfer residual toner was measured. Table 2 shows the transfer rates for solid images of R, G, and B. The transfer rate was determined by (transfer rate) = (developed toner amount−transfer residual toner amount) / (developed toner amount).
(6) Haze Degree Using the evaluation machines A, B, and C, red (R), green (G), and blue (B) two-color superimposed solid images (30 mm × 80 mm) are each 0.80 ± 0. With a toner adhesion amount of 1 mg / cm ² (0.40 ± 0.05 mg / cm ² per toner color), the toner is output to a Ricoh OHP sheet type PPC-DX (fixing temperature 160 ± 2 ° C.). The haze degree was measured by a direct reading haze degree computer HGM-2DP type (manufactured by Suga Test Instruments Co., Ltd.). The haze degree is also referred to as haze, and is measured as a scale indicating the transparency of the toner. The lower the value, the higher the transparency, and the better the color developability when an OHP sheet is used. In Table 2, the results are represented by ranks of 1 to 5, and 5 when the haze is 20% or less, 4 when 21 to 30%, 3 when 31 to 50%, and 51 to 70%. In the case of 1, it was 2, and in the case of 71% or more, it was 1.

Example 1
~ Preparation of aqueous phase ~
990 parts of water, 80 parts of an aqueous dispersion of a vinyl resin (styrene salt copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate), 48.5% of sodium dodecyl diphenyl ether disulfonate 45 parts of an aqueous solution (Eleminol MON-7, manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate were mixed and stirred to obtain a milky white liquid. This is referred to as [aqueous phase].
~ Synthesis of ketimine ~
170 parts of isophorone diamine and 75 parts of methyl ethyl ketone were charged into a reaction vessel equipped with a stir bar and a thermometer, and reacted at 50 ° C. for 5 hours to obtain a blocked amine. This is referred to as [ketimine compound]. The amine value of this [ketimine compound] was 418.
~ Preparation of masterbatch ~
1200 parts of water, 50 parts of carbon black (Cabot Corporation, Regal 400R), 50 parts of polyester resin (manufactured by Sanyo Kasei, RS801), and further 30 parts of water are added 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 [Bk master batch]. In addition, C.I. I. PigmentRed 269, C.I. I. Pigment Blue 15: 2, C.I. I. A magenta master batch [M master batch], a cyan master batch [C master batch], and a yellow master batch [Y master batch] were prepared in the same manner except that Pigment Yellow 155 was used instead of carbon black.
~ Preparation of oil phase ~
A container equipped with a stir bar and a thermometer was charged with 500 parts of a polyester resin (manufactured by Sanyo Chemical Co., Ltd., RS801), 30 parts of carnauba wax, and 850 parts of ethyl acetate. After maintaining the time, it was cooled to 30 ° C. over 1 hour, and using a bead mill (Ultra Visco Mill, manufactured by IMEX), liquid feeding speed: 1 Kg / hr, disk peripheral speed: 6 m / second, 0.5 mm The wax was dispersed under the conditions of zirconia bead filling amount: 80% by volume and pass number: 3 times. Next, 110 parts of [Bk masterbatch] and 500 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain a dissolved product. This is designated as [Bk raw material solution]. [M raw material solution], [C raw material solution], respectively, except that [M master batch], [C master batch], and [Y master batch] were used instead of [Bk master batch]. [Y raw material solution] was obtained.
[Bk raw material solution] 900 parts are transferred to a container, 50 parts of ethyl acetate and 165 parts of MEK are added, and using the above bead mill, liquid feeding speed: 1 Kg / hr, disk peripheral speed: 8 m / second, 0.5 mm A dispersion was obtained under the conditions of zirconia bead filling amount: 80% by volume and pass number: 3 times. This is designated as [Bk pigment / wax dispersion]. Also, instead of [Bk raw material solution], [M raw material solution] was used, and the bead mill dispersion conditions were as follows: liquid feed rate: 0.5 kg / hr, disk peripheral speed: 12 m / sec, 0.5 mm zirconia bead filling amount : A dispersion prepared by changing the conditions to 80% by volume and the number of passes: 3 times is referred to as [M pigment / wax dispersion]. Also, instead of [Bk raw material solution], [C raw material solution] was used, and the bead mill dispersion conditions were as follows: liquid feed rate: 0.5 kg / hr, disk peripheral speed: 10 m / sec, 0.5 mm zirconia bead filling amount : A dispersion prepared by changing the conditions to 80% by volume and the number of passes: 5 times is referred to as [C pigment / wax dispersion]. Also, instead of [Bk raw material solution], [Y raw material solution] was used, and the bead mill dispersion conditions were as follows: liquid feeding speed: 0.5 kg / hr, disk peripheral speed: 10 m / sec, 0.5 mm zirconia bead filling amount : A dispersion prepared by changing the conditions to 80% by volume and the number of passes: 3 times is referred to as [Y pigment / wax dispersion].
~ Emulsification ~
[Bk pigment / wax dispersion] 1772 parts, 50% ethyl acetate solution of prepolymer (number average molecular weight 3800, weight average molecular weight 15000, Tg 60 ° C., acid value 0.5, hydroxyl value 51, and free isocyanate content are 1.53 wt%) 100 parts and 7.5 parts of [ketimine compound] are put in a container, mixed for 1 minute at 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika), 1200 parts were added and mixed with a TK homomixer at a rotational speed of 7,500 rpm for 20 minutes to obtain an aqueous medium dispersion. This is designated as [Bk emulsified slurry]. Further, instead of [Bk pigment / wax dispersion], [M pigment / wax dispersion], [C pigment / wax dispersion], and [Y pigment / wax dispersion] were used in the same manner. [M emulsified slurry], [C emulsified slurry], and [Y emulsified slurry] were obtained.
-Deorganic solvent, washing, drying-
[Bk emulsified slurry] 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 performed at 45 ° C. for 4 hours to obtain a dispersion from which the organic solvent is distilled off. It was. After 100 parts of this dispersion was filtered under reduced pressure,
(1): 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes), and then filtered.
(2): 100 parts of a 10% aqueous sodium hydroxide 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 drier and sieved with a mesh having a mesh size of 75 μm to obtain toner base particles. This is referred to as [Bk toner base]. [M toner base], [C toner base], [C emulsion base], [C emulsion base], [C emulsion base], [C emulsion base] [Y toner base material] was obtained.

~ Mixing of external additives ~
100 parts by weight of the [Bk toner base material] obtained above, 1.0 part by weight of hydrophobic silica (manufactured by Clariant Japan) as an external additive, and 0.5 part by weight of hydrophobic titanium oxide (manufactured by Teica) were added to Henschel. The toner was obtained by mixing with a mixer and passing through a sieve having an aperture of 38 μm to remove aggregates. This is black toner [Bk toner 1]. In the same manner, except that [M toner base], [C toner base], and [Y toner base] are used instead of [Bk toner base], magenta toner [M toner 1] and cyan toner [C Toner 1] and yellow toner [Y toner 1] were obtained.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the four color toners obtained.

  Next, using the toner, a developer was prepared by the method described in <Preparation of two-component developer>, and Table 2 shows each evaluation result for the above <evaluation item>. Evaluation machine A was used as the evaluation machine.

Comparative Example 1
[Y Toner 2] was obtained in the same manner as in Example 1 except that the bead mill dispersion conditions of [Y pigment / wax dispersion] in the oil phase adjustment described in Example 1 were changed as follows. It was.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 1], [C toner 1], and [Y toner 2] were used as toners. It was shown in 2.

Bead mill dispersion conditions of [Y pigment / wax dispersion] Liquid feeding speed: 1 Kg / hr, disk peripheral speed: 8 m / sec, number of passes: 2 times

Comparative Example 2
[Y toner 3] was obtained in the same manner as in Example 1 except that the bead mill dispersion conditions of [Y pigment / wax dispersion] in the oil phase adjustment described in Example 1 were changed as follows. It was.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 1], [C toner 1], and [Y toner 3] were used as toners. It was shown in 2.

Bead mill dispersion conditions of [Y pigment / wax dispersion] Liquid feeding speed: 0.5 Kg / hr, disk peripheral speed: 12 m / sec, number of passes: 5 times

Comparative Example 3
Except that the bead mill dispersion conditions of [M pigment / wax dispersion] and [C pigment / wax dispersion] in the oil phase adjustment described in Example 1 were changed as follows, the same as in Example 1 Thus, [M toner 2] and [C toner 2] were obtained.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation is performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 2], [C toner 2], and [Y toner 1] are used as toners, and the evaluation machine B is used as an evaluation machine. The measured values and the evaluation results are shown in Table 2.

Bead mill dispersion conditions of [M pigment / wax dispersion] Feed speed: 0.5 Kg / hr, disk peripheral speed: 12 m / sec, number of passes: 2 times [M pigment / wax dispersion] beads mill dispersion conditions Feed speed : 1Kg / hr, disk peripheral speed: 8m / sec, number of passes: 2 times

Example 2
[C Toner 3] was obtained in the same manner as in Example 1 except that the bead mill dispersion conditions of [C pigment / wax dispersion] in the oil phase adjustment described in Example 1 were changed as follows. It was.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 2], [C toner 3], and [Y toner 1] were used as toners. It was shown in 2.

Bead mill dispersion conditions for [C pigment / wax dispersion] Liquid feeding speed: 0.5 Kg / hr, disk peripheral speed: 10 m / sec, number of passes: 3 times

Example 3
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 2], [C toner 2], and [Y toner 1] were used as toners. It was shown in 2.

Example 4
The bead mill dispersion conditions of [M pigment / wax dispersion], [C pigment / wax dispersion], and [Y pigment / wax dispersion] in the adjustment of the oil phase described in Example 1 were changed as follows. In the preparation of the aqueous phase, 28 parts of a 3.0% aqueous solution of the polymer protective colloid carboxymethylcellulose (Serogen BSH, manufactured by Sanyo Chemical Industries) was added to the aqueous phase, and in the emulsification step, the TK homopolymer after addition of the aqueous phase was added. Example 1 except that the number of revolutions of the mixer and the stirring time were changed to 10,500 rotations and 10 minutes, and the aqueous medium dispersion was changed to quickly dilute with 2000 parts of pure water after the completion of stirring. Thus, [M toner 3], [C toner 4], and [Y toner 4] were obtained.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 3], [C toner 4], and [Y toner 4] were used as toners. It was shown in 2.

Bead mill dispersion conditions of [M pigment / wax dispersion] Feed speed: 0.5 Kg / hr, disk peripheral speed: 12 m / sec, number of passes: 2 times [M pigment / wax dispersion] beads mill dispersion conditions Feed speed : 1 Kg / hr, disk peripheral speed: 8 m / second, number of passes: 3 times [Y pigment / wax dispersion] bead mill dispersion condition Liquid feed speed: 0.5 Kg / hr, disk peripheral speed: 10 m / second, number of passes : 3 times

Example 5
Evaluation is performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 3], [C toner 4], and [Y toner 4] are used as toners, and the evaluation machine C is used as an evaluation machine. The measured values and the evaluation results are shown in Table 2.

Comparative Example 4
[M Toner 4] was obtained in the same manner as in Example 1 except that the bead mill dispersion conditions of [M Pigment / Wax Dispersion] in the oil phase adjustment described in Example 1 were changed as follows. It was.
Table 1 shows the surface pigment abundance ratio, volume average particle diameter (Dv), Dv / Dn, and average circularity of the obtained toner.
Evaluation was performed in the same manner as in Example 1 except that [Bk toner 1], [M toner 4], [C toner 2], and [Y toner 1] were used as toners. It was shown in 2.

Bead mill dispersion conditions for [M pigment / wax dispersion] Liquid feeding speed: 1 Kg / hr, disk peripheral speed: 8 m / sec, number of passes: 2 times

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. FIG. 2 is a schematic explanatory diagram of a surf fixing device. FIG. 2 is a schematic explanatory diagram of an IH fixing device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating roller 2 Fixing roller 2a Core metal 2b Elastic member 3 Heat resistant belt (toner heating medium)
DESCRIPTION OF SYMBOLS 4 Pressure roller 4a Metal core 4b Elastic member 5 Temperature detection means 6 Induction heating means 7 Excitation coil 8 Coil guide plate 9 Excitation coil core 11 Recording material 10 Photoconductor 12 Excitation coil core support member 20 Charging roller 30 Exposure means 40 Development means 41 Development Belt 42 Developer container 43 Supply roller 44 Conveyance roller 45 Development unit 50 Intermediate transfer member 51 Suspension roller 52 Corona charger 60 Cleaning means 70 Static elimination lamp 80 Transfer roller 90 Cleaning means 100 Transfer paper

Claims (10)

An intermediate transfer body for sequentially transferring a toner image formed by developing an electrostatic latent image with a full-color image forming toner containing at least a binder resin and a colorant, and an image toner on the intermediate transfer body A full-color image forming apparatus having re-transfer means for re-transferring onto a recording medium to form a toner image, wherein one of the full-color image forming toners is a yellow toner, and a surface colorant of toner particles of the yellow toner The abundance ratio (Y) is 1.4 to 2.0, the surface colorant abundance ratio of the other color toner particles is smaller than Y, and transfer of yellow toner to the intermediate transfer member is possible. A full-color image forming apparatus, wherein the full-color image forming apparatus is formed prior to the transfer of the other color image forming toner. Wherein among the layered made from the intermediate transfer member from the multicolor transferred onto the recording medium the toner, to claim 1, wherein the yellow toner layer is characterized in that the top from the image forming toner layers of other color- The full-color image forming apparatus described. The color-forming image toner other than the yellow toner contains at least a magenta toner and a cyan toner, and the surface colorant abundance ratio (M) of the magenta toner is 1.3 to 1.7, The full color image according to claim 1 or 2 , wherein the surface colorant abundance ratio (C) of the cyan toner is 1.0 to 1.7, and M <Y or C <Y. Forming equipment. 4. The full-color image forming apparatus according to claim 3 , wherein the color toner is transferred onto the intermediate transfer member in the order of yellow toner, cyan toner, and magenta toner, and M <C <Y. The yellow toner colorant, azo pigments, or full-color image forming apparatus according to any one of claims 1 to 4, characterized in that a quinacridone pigment. The toner dissolves or disperses at least a compound having an active hydrogen group, a polymer having a site capable of reacting with the active hydrogen group, and a colorant in an organic solvent, and disperses the solution or dispersion in an aqueous medium. Obtained by reacting the compound having the active hydrogen group with the polymer having a site capable of reacting with the active hydrogen group, or by reacting or removing the organic solvent, washing and drying. full-color image forming apparatus according to any one of claims 1 to 5, characterized in that a toner. The volume average particle diameter (Dv) of the toner particles of the toner is 3.0 to 7.0 μm, and the ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) (Dv / Dn) full-color image forming apparatus according to any one of claims 1 to 6 value is equal to or 1.25 or less. Full-color image forming apparatus according to any one of claims 1 to 7 average circularity of the toner particles of the toner is characterized by a 0.94 to 0.99. Fixing means having a recording medium on which an unfixed toner image is formed, a heating body having a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film the full-color image forming apparatus according to any one of claims 1 to 8 to pass between the said film pressing member, characterized in that heat-fixing the unfixed image. The recording medium on which the unfixed toner image is formed is composed of a magnetic roller and heated by electromagnetic induction, a fixing roller arranged in parallel with the heating roller, the heating roller and the fixing roller, An endless belt-shaped toner heating medium that is stretched between and heated by the heating roller and rotated by the rollers, and is pressed against the fixing roller via the toner heating medium, and the toner heating medium The fixing unit having a pressure roller that rotates in the forward direction to form a fixing nip portion with respect to the rotation method is passed between the toner heating medium and the pressure roller to heat the unfixed image. full-color image forming apparatus according to any one of claims 1 to 9, characterized in that the fixing.

Images