JP2007065351A - Developing method and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing method and an image forming method, with which an image showing preferable gloss and fixing property with less density uneveness (roughness) of an image can be obtained and a stable image similar to that in an initial stage can be obtained continuously, even over long-term continuous use. <P>SOLUTION: The toner to be used has toner particles containing at least a binder resin and a colorant, wherein the loss tangent (tanδ) of the toner has a minimum and maximum values in a temperature range of 70 to 110°C and a maximum value in the temperature range of 140 to 200°C, and the loss modulus G"(140) of the toner ranges from 1.0×10<SP>4</SP>to 2.0×10<SP>5</SP>dN/m<SP>2</SP>. The developing roller to be used has surface characteristics, represented by a circular slicing characteristic value X (ϕ0.050) of 0.8 to 2.4 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing method and an image forming method used in a recording method using an electrophotographic method, an electrostatic recording method, or the like. Specifically, the present invention relates to a developing method for developing an electrostatic latent image formed on an electrostatic latent image carrier with toner. The present invention also relates to an image forming method used in a copying machine, a printer, and a fax machine in which an electrostatic latent image formed on an electrostatic latent image carrier is developed with toner and then transferred onto a transfer material to form an image. is there.

  In an electrophotographic apparatus that uses an electrophotographic system for image formation, such as a copying machine, a facsimile machine, and a printer, toner, a developing roller, and the like are used in the developing process and the image forming process. For example, in an electrophotographic apparatus of a one-component development system, a developing roller carrying toner on the surface thereof is used in the process of developing an electrostatic latent image formed on the surface of a photosensitive drum with toner, that is, in the developing process. A method is used in which the toner is moved in contact with or pressed against the surface of a photosensitive drum as a latent image carrier.

  In an image forming apparatus that forms an image using toner, the gloss (gloss) of a fixed image obtained may vary depending on the type of transfer material used. This is because the surface roughness of the transfer material affects the surface smoothness of the fixed toner image.

  In some cases, a high-gloss image is intentionally obtained using a transfer material having a smooth surface, but even when a transfer material having a different surface property is used, it is often desired to obtain an equivalent gloss. For example, there is a case where a document used as a transfer material is created by mixing recycled paper and high-quality paper.

  Here, as means for controlling the gloss to an arbitrary value, there is usually a method of changing the fixing speed and temperature in accordance with the paper type. However, this method often slows the fixing speed and raises the fixing temperature, which is problematic from the viewpoint of usability and energy saving.

  As other means for controlling the gloss to an arbitrary value, the maximum endothermic peak and molecular weight distribution are defined, and furthermore, by using a toner having specific viscoelastic properties, an image having an appropriate gloss in a wide temperature range is obtained. There are methods (Patent Documents 1 and 2). However, with the toners described in these documents, it is difficult to make the image gloss within a suitable range when different types of transfer materials are used under the same fixing conditions.

  Further, the developing roller is required to have a stable toner transportability, and the roller surface is adjusted to an appropriate surface roughness. For example, a method using a resin containing organic polymer compound particles having a particle size of 10 to 150 μm in the surface layer is known (Patent Document 3). In particular, the method of adding the particle component to obtain the surface roughness in the surface layer can omit the polishing step and is also a simple method for adjusting the surface roughness.

In adjusting the surface roughness of the developing roller, emphasis is placed on controlling the toner transportability, and it has been generally performed to adjust the particle size and the amount of addition. In the case of using a soft toner capable of obtaining a good gloss image or a good fixability as described above, the density of the image varies depending on the toner transportability of the developing roller, specifically, the uniformity of the toner coat. Unevenness (especially roughness in a minute area) tends to be more noticeable as the gloss becomes better. Further, even when the initial image is good, there is a problem that density unevenness becomes more conspicuous in an image in continuous use for a long time.
JP 2001-75305 A JP 2004-151638 A Japanese Patent No. 3112489

  The present invention is capable of producing an image having little unevenness of image density (glossiness), good gloss and good fixability, and capable of maintaining a stable image similar to the initial stage even during continuous use over a long period of time. A method and an image forming method are provided.

  As a result of intensive studies, the present inventors have used the toner having a specific dynamic viscoelastic property as the toner, and at the same time, if a developing roller having a specific surface shape is also used as the developing roller, the above-described problem occurs. Finally, the present invention has been found.

That is, the present invention applies toner to the electrostatic latent image formed on the latent image carrier in a state where the developing roller carrying the toner is in contact with or pressed against the latent image carrier. In a developing method for visualizing a latent image as a toner image, the toner has toner particles containing at least a binder resin and a colorant, and the dynamic viscoelastic properties of the toner measured at a frequency of 6.28 rad / sec. , Loss tangent (tan δ) has a minimum value and a maximum value in a temperature range of 70 to 110 ° C., a maximum value in a temperature range of 140 to 200 ° C., and a loss elastic modulus G ″ at 140 ° C. ( 140 ° C.) is 1.0 × 10 ^{4 to} 2.0 × 10 ⁵ dN / m ² , and the developing roller draws a circle having a diameter of 0.050 mm on the outer peripheral surface along the circle. Circular slicing characteristic value X (φ0.05 0) is in the range of 0.8 to 2.4 μm.

As a developing roller, the circular slicing characteristic value X (φ0.050) with a diameter of 0.050 mm was measured at three locations along the circumference at five locations in the longitudinal direction (total of 15 locations), and the larger measured value It is preferable that the following equation 1 is satisfied among the three average values X _max , the smaller three average values X _min, and the average value X _avg of all the measured values.
(X _max −X _min ) / X _avg ≦ 0.5 (Formula 1)

Further, when the developing roller measures the circular slicing characteristic value X (φM) every 0.010 mm concentrically with a diameter of 0.050 to 0.100 mm, the following formula 2 is calculated between the adjacent values. It is preferable that it is satisfied.
0.8 ≦ X (φM) / X (φM ± 0.010) ≦ 1.25 (Formula 2)

Furthermore, in the present invention, the developing roller has elastic particles blended on the outer peripheral surface thereof, and the elastic particles have a maximum Stokes equivalent diameter Dst in the distribution curve of the Stokes equivalent diameter measured by the centrifugal sedimentation analysis method and a half of the Stokes equivalent diameter Dst. It is preferable that the value width ΔD50 satisfies the following formula 3.
ΔD50 / Dst ≦ 0.60 (Formula 3)

  In the present invention, the main component of the binder resin contained in the toner particles is preferably a vinyl copolymer.

The average circularity A _avg of the toner is preferably 0.960 to 0.995.

  Furthermore, the present invention is an image forming method characterized in that the toner image formed on the latent image carrier is transferred to a transfer material and then fixed using the above developing method.

  According to the present invention, it is possible to obtain an image having little unevenness of image density (glossiness), good gloss and good fixability, and a stable image similar to the initial stage can be maintained even during continuous use over a long period of time. Development methods and image forming methods are provided.

In the developing method of the present invention, the toner carried on the developing roller in contact with or in pressure contact with the latent image carrier is applied to the electrostatic latent image formed on the latent image carrier to obtain a toner image. In a dynamic viscoelastic property measured at a frequency of 6.28 rad / sec, the toner has toner particles containing at least a binder resin and a colorant. The loss tangent (tan δ) has a minimum value and a maximum value in a temperature range of 70 to 110 ° C., a maximum value in a temperature range of 140 to 200 ° C., and a loss elastic modulus G ″ at 140 ° C. (140 ° C) is 1.0 × 10 ^{4 to} 2.0 × 10 ⁵ dN / m ² , and the circular slicing characteristic value X (φ 0.050) is 0.8 to ² when the developing roller has a diameter of 0.050 mm. .Characterized by being in the range of 4 μm In the following, unless otherwise specified, the dynamic viscoelastic properties are measured at a frequency of 6.28 rad / sec.In the present invention, the storage elastic modulus G ′ and loss elastic modulus measured at Y ° C. When G ″ and loss tangent tan δ (= G ″ / G ′) are indicated, they are described as “G ′ (Y ° C.)”, “G” (Y ° C.) ”, and“ tan δ (Y ° C.) ”, respectively.

  In the present invention, the circular slicing characteristic value X (φM) of the developing roller uses a 50 × objective lens on the outer peripheral surface of the developing roller by a three-dimensional optical profiler system (manufactured by ZYGO, trade name: NewView 5010). Then, a Filled plot is measured with an area of 0.1 mm square or more and a scan height of 200 μm. A circle with a diameter of Mmm is drawn on the obtained plot, and a sectional curve f on the entire circumference (πMmm) along the circle is drawn. It is the arithmetic average height of the cross-sectional curve obtained from the average of the absolute values of (x). It should be noted that the deflection from the roller shape is derived from the surface of the best-fit cylinder and corrected by numerical processing.

  First, the structure of the developing roller used in the present invention and a specific apparatus to which the developing method of the present invention is applied will be described.

  FIG. 1 is a schematic cross-sectional view of an example of a developing roller used in the present invention.

  In FIG. 1, reference numeral 1 denotes a developing roller. The developing roller 1 has an elastic body layer 12 formed on a columnar or hollow cylindrical substrate 11 having at least a conductive surface, and a surface layer on the outer peripheral surface thereof. 13 is formed. An adhesive layer may be formed between the base 11 and the elastic layer 12, and a layer that imparts functionality may be provided between the elastic layer 12 and the surface layer 13. Furthermore, each layer does not need to be a single layer, and may be a multilayer if necessary. In the present invention, it is important that the shape of the surface of the developing roller is specific in the circular slicing characteristic value.

  FIG. 2 is a schematic diagram of an example of an image forming apparatus using a process cartridge suitable for applying the developing method of the present invention. Here, in order to make the explanation easy to understand, the following description will be given using a schematic diagram of an image forming apparatus for monochrome, that is, monochrome printing.

  The photosensitive drum 21, which is an image forming body, a charging roller (charging device) 22, a developing roller 25, a supply roller 26, an elastic blade 27 which is a toner layer thickness regulating member, a stirring blade 24, and toner 28 are combined into one process cartridge. The image forming apparatus 3 can be exchanged integrally.

  The photosensitive drum 21 uniformly charged by the charging roller 22 rotates in the direction of arrow A, and the surface is irradiated with a laser beam 40 carrying recording information between the charging roller 22 and the developing roller 25, thereby electrostatically A latent image is formed. On the other hand, the toner 28 sent to the supply roller 26 by the stirring blade 24 is uniformly coated on the surface of the developing roller 25 by the elastic blade 27, is carried to the surface of the photosensitive drum 21, and is formed on the surface of the photosensitive drum 21. The electrostatic latent image is visualized as a toner image. When the photosensitive drum 21 further rotates and the toner image reaches the transfer region, the toner image is transferred onto a transfer material 33 such as paper by a transfer roller 29 that faces the photosensitive drum 21. The surface of the photosensitive drum 21 is uniformly charged again by the charging roller 22 after the toner remaining without being transferred to the transfer material 33 is removed by the cleaning blade 30.

  The unfixed toner image transferred to the transfer material 33 is fixed to the transfer material 33 by pressure and heat in the fixing device 32 and is discharged from the image forming device 3.

  On the other hand, the toner that is not used for development and remains on the surface of the developing roller 25 returns to the developing container 34 while being held on the surface of the developing roller 25. Inside the developing container 34, the supply roller 26 removes toner remaining on the surface of the developing roller 25 from the surface of the developing roller 25 and supplies new toner to the surface of the developing roller 25. The new toner supplied to the surface of the developing roller 25 is uniformly adjusted in thickness by the elastic blade 27 and conveyed to the developing area. By repeating this, new toner is always uniformly coated on the developing roller 25, and the electrostatic latent image is developed.

  The developing roller 25 is in contact with the photosensitive drum 21 with a contact width. Further, the structure of the supply roller 26 that is in contact with the contact portion of the elastic blade 27 with the surface of the developing roller 25 in the developing container 34 on the upstream side in the rotation direction B of the developing roller 25 and is rotatably supported. For example, a foamed skeleton-like sponge structure or a fur brush structure in which fibers such as rayon or polyamide are planted on a core metal is preferably used from the viewpoint of supplying new toner to the developing roller 25 and stripping off undeveloped toner. . The supply roller 26 preferably has a contact width with respect to the developing roller 25 and has an appropriate relative speed, and is driven to rotate by a driving means (not shown).

  Further, the transfer roller 29 that transfers the toner image on the photosensitive drum 21 to the transfer material 33 is pressed from the back surface of the transfer material 33 in an area for holding the toner image on the photosensitive drum 21, and is in contact with the surface of the photosensitive drum 21. Transfer of the toner image to the surface of the transfer material 33 is promoted by the difference in the bias voltage. The transfer material 33 is automatically inserted into a portion (transfer area) where the photosensitive drum 21 and the transfer roller 29 are in rotational contact.

  Although an example of a single color is shown here, it may be a color image forming apparatus that forms toner images of four colors of cyan, magenta, yellow, and black, and the configuration thereof is also formed on the photoreceptor. The toner image of each color that has been transferred is temporarily transferred to a transfer roller or a transfer belt, the toner image is directly transferred onto a transfer material, the photoconductor is provided for each color, and there is one photoconductor Thus, it is possible to make various modifications such as one in which each color developing device is configured to come into contact with the photosensitive member when a toner image of the assigned color is formed.

A feature of the present invention is that the toner has toner particles containing at least a binder resin and a colorant, and the loss tangent (tan δ) of the toner measured at a frequency of 6.28 rad / sec is 70 to 110 ° C. Has a minimum value and a maximum value in a temperature range of 140 to 200 ° C., and a loss elastic modulus G ″ (140 ° C.) of 1.0 × 10 ^{4 to} 2.0 × 10 ⁵ dN / m ² and the developing roller has a circular slicing characteristic value X (φ0.050) in the range of 0.8 to 2.4 μm.

That is, in the present invention, the toner to be used contains toner particles having at least a binder resin and a colorant, and the loss tangent (tan δ) measured at a frequency of 6.28 rad / sec of the toner is 70 to 110 ° C. It has a minimum value and a maximum value in the range, has a maximum value in the temperature range of 140 to 200 ° C., and has a loss elastic modulus G ″ (140 ° C.) of 1.0 × 10 ^{4 to} 2.0 × 10 ^5. Must be dN / m ² .

When the toner G ″ (140 ° C.) is less than 1.0 × 10 ⁴ dN / m ² , the toner has excellent followability to the unevenness on the surface of the transfer material, but the toner is too soft, Since the gloss difference of the transfer material itself is reflected too much, it is difficult to make the gloss value in an appropriate range, and conversely, if it exceeds 2.0 × 10 ⁵ dN / m ² , the unevenness on the surface of the transfer material Therefore, the toner is inferior in the followability to the toner, and the fixing property with the transfer material is deteriorated, so that an image with good storage stability cannot be provided.

  The toner used in the present invention has a maximum value and a minimum value in a temperature range where the loss tangent tan δ (= G ″ / G ′), which is the ratio between the loss elastic modulus G ″ and the storage elastic modulus G ′, is 70 to 110 ° C. It is necessary to have a value (hereinafter, the maximum value and the minimum value in this temperature range are referred to as “maximum value 1” and “minimum value 1”, respectively).

  A maximum value of 1 for tan δ is observed when the binder resin transitions from a glass state to a thermally deformable state, suggesting that the micro-Brownian motion of the polymer chains constituting the binder resin is activated at that temperature. is doing. Further, the minimum value 1 of tan δ indicates that the binder resin is in a state where it flows and deforms easily even when no force is applied from the outside, and the release agent component in the toner tends to ooze out at that temperature. Suggests that Therefore, the temperature when tan δ takes the maximum value 1 is lower than the temperature when tan δ takes the minimum value 1.

  If the temperature at which tan δ takes a maximum value of 1 is less than 70 ° C., the toner particles are easily deformed and damaged by the frictional heat with the charging member. If the temperature at which tan δ takes a minimum value of 1 cannot be prevented and the tan δ is over 110 ° C., the wax as a release agent does not exude effectively, and the toner image is transferred to a transfer material. The fixability of the ink will deteriorate.

  Further, the toner used in the present invention needs to have a maximum value even in a temperature range where tan δ is 140 to 200 ° C. (hereinafter, the maximum value in this temperature range is referred to as “maximum value 2”).

  The fact that tan δ has a maximum value 2 in this temperature range indicates that the rate of decrease in the storage elastic modulus G ′, which has decreased as the measured temperature rises, is moderate in the vicinity of the temperature at which the maximum value 2 is exhibited. ing. This means that the temperature dependence of G ′ is smaller than that of the conventional one in the vicinity of the temperature at which the toner is in a molten state.

In the present invention, the dynamic viscoelastic properties (G ′, G ″, tan δ) are measured as follows.
Measuring device: Dynamic viscoelasticity measuring device ARES (trade name, manufactured by Rheometric Scientific F.E.)
Measurement sample: The toner is pressure-molded to form a measurement sample in a disk shape having a diameter of about 8 mm and a height of about 2 mm.
・ Measurement jig: A circular parallel plate with a diameter of 8 mm and a shallow cup corresponding to the circular parallel plate on the drive side are used. The gap between the bottom of the shallow cup and the circular plate is about 2 mm.
Measurement frequency: 6.28 radians / second.
・ Measurement strain setting: Set the initial value to 0.1% and then set to automatic measurement mode.
-Sample elongation correction: Adjust in automatic measurement mode.
-Measurement temperature: 40-200 degreeC. Temperature rising 2 ° C./min.

  FIG. 3 shows the measurement results of the storage elastic modulus G ′ and loss elastic modulus G ″ of an example of the toner used in the present invention, and FIG. 4 shows the loss tangent (tan δ) obtained from the results.

  As seen in these figures, the toner used in the present invention has a maximum value 1 and a minimum value in the temperature range of 70 to 110 ° C. in the loss tangent (tan δ) determined from the storage elastic modulus G ′ and the loss elastic modulus G ″. The value 1 exists, and the maximum value 2 also exists in the temperature range 140 to 200 ° C.

  The toner used in the present invention has toner particles containing at least a binder resin and a colorant.

  In order to obtain a toner having suitable values for G ″ (140 ° C.) and tan δ, there is a method of adjusting the molecular weight distribution of the binder resin. Specifically, the reaction temperature during the synthesis of the binder resin is adjusted. Examples of the method include adjusting the initiator type and the initiator addition amount to be suitable, etc. The weight average molecular weight (Mw) can be controlled by gel permeation chromatography (GPC).

  In addition, a rough cross-linked structure is provided in the binder resin, and the temperature gradient of G ′ near the fixing temperature is moderated. Specifically, a compound having a molecular weight of about 200 to 300 and having double bonds at both ends is provided. For example, a metal compound may be introduced as a crosslinking component, or a metal compound may be added in the initial stage of the polymerization reaction in toner production by a polymerization method to cause a very weak metal crosslinking reaction to proceed in the monomer droplets.

The toner used in the present invention can also be produced by a pulverization method, but the toner particles obtained by this pulverization method are generally amorphous and have good performance, for example, average circularity A _avg described later. In order to make it 0.960 or more, it is necessary to classify after the pulverization treatment or mechanical and thermal treatment without classification.

  The binder resin is preferably a resin mainly composed of a vinyl copolymer. A copolymer of a compound selected from styrene or a styrene monomer as a vinyl copolymer, a copolymer of a compound selected from styrene or a styrene monomer and a compound selected from acrylates The vinyl copolymer is preferably contained in an amount of 50% by mass or more, more preferably 80% by mass or more of the binder resin component. The binder resin used together with the vinyl copolymer component is not particularly limited, but is appropriately selected from toner resins used in electrophotographic apparatuses.

  By using a vinyl copolymer as a main component, image quality such as fine line reproducibility and density stability of an image can be maintained in a suitable state. It is presumed that the charging properties, environmental stability, brittleness, and other physical properties of the vinyl copolymer act comprehensively to maintain developability and transferability at the same level.

Examples of the method for producing the vinyl copolymer include a direct polymerization method, a suspension polymerization method, an emulsion polymerization method, an emulsion association polymerization method, and a seed polymerization method. In view of easy balance, it is particularly preferable to produce the suspension by a suspension polymerization method. In this suspension polymerization method, a monomer composition is prepared by uniformly dissolving or dispersing a colorant (and, if necessary, a polymerization initiator, a crosslinking agent, a charge control agent, and other additives) in the polymerizable monomer. Then, the monomer composition is dispersed in a dispersion stabilizer-containing continuous layer (for example, an aqueous phase) using an appropriate stirrer, and a polymerization reaction is performed to obtain a toner having a desired particle size. To get. In the case of producing a toner by this suspension polymerization method, since the individual toner particle shapes are almost spherical, it is easy to obtain a toner satisfying the requirement that the average circularity A _avg described later is 0.960 or more, Further, since such toner has a relatively uniform charge amount distribution, it has high transferability.

  Furthermore, a toner having a core / shell structure in which a surface layer is provided by adding a polymerizable monomer and a polymerization initiator to the fine particles obtained by suspension polymerization can be designed as necessary. .

  As the polymerizable monomer used for the production of the vinyl polymer, a styrene monomer such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene, etc. Body, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-acrylate Acrylic esters such as chloroethyl and phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-methacrylic acid 2- Ethyl hexyl, methacrylate Allyl, phenyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid esters such as diethylaminoethyl methacrylate and other acrylonitrile-methacrylonitrile-monomer acrylamide. These monomers are used in combination as appropriate.

  Further, in order to improve the performance of the binder resin, a crosslinkable monomer may be used in combination, and a compound having two or more polymerizable double bonds is used, specifically, divinylbenzene, divinyl. Aromatic divinyl compounds such as naphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate; divinylaniline, divinyl ether, divinyl A divinyl compound such as sulfide or divinylsulfone; and a compound having three or more vinyl groups are used alone or in combination. In addition, 0.001-15 mass% of all the monomers are used for a crosslinkable monomer.

  In the production of the polymerized toner according to the present invention, a resin may be added to the monomer system for polymerization. For example, hydrophilic functional groups such as amino groups, carboxylic acid groups, hydroxyl groups, sulfonic acid groups, glycidyl groups, nitrile groups, etc. that cannot be used because monomers are water-soluble and dissolve in aqueous suspension to cause emulsion polymerization. When it is desired to introduce the monomer component contained in the toner, it may be in the form of a copolymer such as a random copolymer of these and a vinyl compound such as styrene or ethylene, a block copolymer, or a graft copolymer, or It can be used in the form of a polycondensate such as polyester or polyamide, a polyaddition polymer such as polyether or polyimine.

  When using such a high molecular polymer containing a polar functional group, the average molecular weight is preferably 5,000 or more. If it is less than 5,000, especially 4,000 or less, the present polymer tends to concentrate near the surface, and this is not preferred because it tends to adversely affect developability and blocking resistance. The polar polymer is particularly preferably a polyester resin.

  In addition, resins other than those described above may be added to the monomer system for the purpose of improving the dispersibility and fixing properties of the material or image characteristics. Examples of the resin used include styrene such as polystyrene and polyvinyltoluene. And 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-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid Acid butyl copolymer, styrene-methacrylic acid dimethylaminoethyl copolymer , Styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer Styrene copolymers such as styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacryl Resins, rosins, modified rosins, terpene resins, phenol resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins and the like can be used alone or in combination.

  As addition amount of these resin, 1-20 mass parts is preferable with respect to 100 mass parts of monomers. If it is less than 1 part by mass, the effect of addition is small, and if it exceeds 20 parts by mass, it is difficult to design various physical properties of the polymerized toner.

  Furthermore, if a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and high offset resistance can be obtained. it can.

  In the present invention, toner particles containing at least the binder resin and a colorant are used as the toner. As the colorant used here, those conventionally used as a colorant for toner in an electrophotographic apparatus can be used without any trouble. That is, an organic pigment, an inorganic pigment, and a dye are appropriately selected and used.

  As the cyan colorant, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment blue 1, C.I. I. Pigment blue 7, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment Blue 66 etc. can be used.

  As the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment violet 19, C.I. I. Pigment red 23, C.I. I. Pigment red 48: 2, C.I. I. Pigment red 48: 3, C.I. I. Pigment red 48: 4, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 81: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 144, C.I. I. Pigment red 146, C.I. I. Pigment red 166, C.I. I. Pigment red 169, C.I. I. Pigment red 177, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment red 202, C.I. I. Pigment red 206, C.I. I. Pigment red 220, C.I. I. Pigment red 221, C.I. I. Pigment Red 254 or the like can be used.

  As the yellow colorant, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are used. Specifically, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 62, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 111, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 127, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 168, C.I. I. Pigment yellow 174, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 176, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. Pigment yellow 191, C.I. I. Pigment Yellow 194 or the like can be used.

  As the black colorant, carbon black, the one obtained by adjusting the color colorant to black, or the like can be used.

  These colorants can be used alone or in combination, and further in a solid solution state.

  The addition amount of the colorant is usually used by adding 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  In the present invention, when the above vinyl copolymer is polymerized, it is preferable to blend these colorants in the polymerization system together with other necessary additives together with the monomer composition. Of course, the toner can also be produced by producing the above vinyl-based copolymer, blending a colorant together with additives necessary for the copolymer, melt-kneading and solidifying, and then performing pulverization, classification, and spheronization. Particles can be obtained.

  In addition, it is also preferable to treat the surface of the colorant in order to increase the dispersibility in the final resin or in the polymerization system during polymerization. For example, carbon black is treated with polyorganosiloxane that reacts with surface functional groups.

  When the toner is color, it is preferable to use a disazo yellow pigment for yellow toner, a quinacridone magenta pigment for magenta toner, and a phthalocyanine cyan pigment for cyan toner.

In the present invention, G ″ (140 ° C.) and tan δ of the toner are specified, that is, tan δ has a maximum value 1 and a minimum value 1 in a temperature range of 70 to 110 ° C., and a temperature of 140 to 200 ° C. The range must also have a maximum value of 2, and G ″ (140 ° C.) must be in the range of 1.0 × 10 ^{4 to} 2.0 × 10 ⁵ dN / m ² . Such a toner can be achieved by appropriately selecting a binder resin. In particular, in the case of a vinyl copolymer, the kind and amount of a crosslinkable monomer, the kind, combination and use of a polymerization initiator are used during polymerization. It is also possible to optimize the amount, polymerization temperature and the like.

  As a polymerization initiator that can be used when the toner particles of the present invention are produced by a polymerization method, a polymerization initiator having a half-life of 0.5 to 30 hours at the time of the polymerization reaction is 0.5 to 100 parts by weight of the polymerizable monomer. When 20 parts by mass is used, a polymer having a maximum between 10,000 and 100,000 is obtained, and the toner particles can be provided with desirable strength and suitable melting characteristics. Specific examples of such a polymerization initiator include 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisiso Azo or diazo polymerization initiators such as butyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile; benzoyl Peroxide, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl It can exhibit peroxide polymerization initiators such as over oxide.

  When the toner particles of the present invention are obtained by a polymerization method, that is, together with the colorant in the polymerizable monomer, components necessary for the toner such as a release agent, a plasticizer, a charge control agent, and other additives, for example, Add organic solvent, polymer, dispersing agent, etc. to reduce the viscosity of the polymer produced by the polymerization reaction, and dissolve uniformly with a disperser such as a homogenizer, ball mill, colloid mill, or ultrasonic disperser. Alternatively, the dispersed monomer system is suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size at a stretch. The polymerization initiator may be added at the same time as other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  After granulation, polymerization may be carried out by stirring using an ordinary stirrer to such an extent that the dispersed state of the particles is maintained and the particles are prevented from floating and settling.

  Known surfactants and organic / inorganic dispersants can be used as dispersion stabilizers. Among them, inorganic dispersants are less likely to produce harmful ultrafine powders, and dispersion stability is obtained due to their steric hindrance, so the reaction temperature can be changed. However, the stability is not easily lost, the cleaning is easy, and the toner is not adversely affected. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; calcium metasuccinate, calcium sulfate and barium sulfate. Inorganic salts: Inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina can be used.

  These inorganic dispersants are desirably used alone in an amount of 0.2 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. However, although it is difficult to generate ultrafine particles, it is somewhat difficult to atomize the toner. Therefore, you may use 0.001-0.1 mass part surfactant together.

  Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, potassium stearate and the like.

  When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed with high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At the same time, water-soluble sodium chloride salt is produced as a by-product. However, if water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner is generated by emulsion polymerization. This is more convenient. Since it becomes an obstacle when removing the remaining polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalinate with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolution with an acid or alkali after completion of the polymerization.

  As the polymerization temperature, a temperature of 40 ° C. or higher, generally 50 to 90 ° C. is appropriate. When the polymerization is carried out in this temperature range, the release agent or wax to be sealed inside is precipitated by phase separation, and the encapsulation becomes more complete. In order to consume the remaining polymerizable monomer, the reaction temperature can be raised to 90 to 100 ° C. at the end of the polymerization reaction.

  The polymerized toner particles are filtered, washed, and dried by a known method after the polymerization is completed, and the toner can be obtained by mixing and adhering the inorganic fine powder to the surface. Moreover, it is one of the desirable forms of this invention to put a classification process in a manufacturing process and to cut coarse powder and fine powder.

  Furthermore, a toner having a core / shell structure in which a surface layer is provided by adding a polymerizable monomer and a polymerization initiator to the fine particles obtained by suspension polymerization can be designed as necessary. .

  When the toner particles are produced by a pulverization method, a known method is used. For example, a binder resin, a release agent, a charge control agent, and in some cases, a coloring agent and other components necessary as a toner and other additives are used. Mix thoroughly with a mixer such as a Henschel mixer or ball mill, then melt and knead using a heat kneader such as a heated roll, kneader, or extruder to disperse other toner materials while mixing the resins with each other. Alternatively, the toner particles can be obtained by dissolving, solidifying by cooling, pulverization, classification, and surface treatment as necessary. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

  The pulverization step can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type.

  The toner particles that can be used in the present invention include a method described in Japanese Patent Publication No. Sho 56-13945, etc., using a disk or a multi-fluid nozzle to atomize the molten mixture in the air to obtain spherical toner particles, or a suspension as a polymerization method. In addition to the polymerization method, a dispersion polymerization method in which a toner particle is directly generated using a water-based organic solvent that is soluble in the monomer and insoluble in the obtained polymer, or directly polymerized in the presence of a water-soluble polar polymerization initiator. It can be produced by an emulsion polymerization method typified by a soap-free polymerization method for producing particles.

  The toner particles that can be used in the present invention may contain a charge control agent in order to stabilize the charge characteristics. As the charge control agent, a known one can be used, and a charge control agent that has a high charging speed and can stably maintain a constant charge amount is particularly preferable. Further, when the toner is produced by a direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable. Specific compounds include, as negative charge control agents, metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid and dicarboxylic acid, metal salts or metal complexes of azo dyes or azo pigments, Examples thereof include a polymer compound having a sulfonic acid or carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, and calixarene. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer compound having the quaternary ammonium salt in the side chain, a guanidine compound, a nigrosine compound, and an imidazole compound. The charge control agent is preferably used in an amount of 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin. However, in the present invention, it is not always necessary to add a charge control agent, and it is sufficient to positively utilize frictional charging with an elastic blade or a developing roller.

  The toner preferably has an average particle diameter of 3 to 10 μm, preferably 4 to 8 μm, in order to faithfully develop fine electrostatic latent image dots.

  The average particle diameter of the toner can be measured using a Coulter Counter TA-II type (trade name, manufactured by Coulter), Coulter Multisizer (trade name, manufactured by Coulter) or the like.

  Specifically, a small amount of a surfactant is added to 100 to 150 ml of an electrolytic aqueous solution, 2 to 20 mg of a measurement sample is further added, and the dispersion is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Using a 100 μm aperture with Multisizer (trade name) or the like, the volume and number of toner particles of 2 μm or more are measured to obtain the volume distribution and the number distribution. A weight average particle diameter (D4) and a number average particle diameter (D1) are calculated from the obtained distribution data.

  As the toner, the above-described toner particles themselves can be used as they are, but various fine powders generally known as external additives are added to the toner particle surfaces as necessary.

  As the external additive, known inorganic fine powder or resin particles can be used, but from the inorganic fine powder of silica, alumina, titania or its double oxide for improving charging stability, developability, fluidity and storage stability. It is preferable to be selected. The external additive may be a silicone varnish, various modified silicone varnishes, silicone oil, various modified silicone oils, a silane coupling agent, or a silane coupling agent having a functional group, if necessary, for the purpose of hydrophobization, charge control, etc. In addition, it may be treated with a treating agent such as an organic silicon compound or an organic titanium compound.

  As the external addition method, a conventionally known method using a Henschel mixer or the like can be used.

In the present invention, the toner preferably has an average circularity A _avg of 0.960 to 0.995.

The average circularity A _avg being 1.000 means that the toner is a perfect sphere as described below, and the closer to 1.000 the toner image is in an unfixed state. The space between them is reduced, and heat is easily transmitted uniformly throughout the toner particles during the fixing process. On the other hand, as A _avg becomes smaller, the distortion of the toner becomes larger, the gaps between the toner particles in the toner image tend to vary, and the way in which heat is transferred to the toner particles becomes uneven, resulting in fixing. Unevenness or peeling is likely to occur in the image.

The average circularity A _avg in the present invention is used as a simple method for quantitatively expressing the shape of the particles. A flow type particle image analyzer (manufactured by Toa Medical Electronics Co., Ltd., type: FPIA-1000) is used. For the particles having an equivalent circle diameter of 3 μm or more, the projection area S _i and the circumference L _i of the projected image of each particle are measured, and the circumference (R _i) of the circle having the same area as the projection area S _i is used as the particle ( The value of i) divided by the peripheral length L _i is the circularity A _i of the particle (i), and is defined as the average value of A _i .

That is, circularity A _i = R _i / L _i , average circularity A _avg = ΣA _i / m (where m is the number of particles measured).

  In addition, when the above calculation is performed by the program attached to the measurement apparatus “FPIA-1000”, the range of the circularity of 0.40 to 1.00 is divided into 61 divided classes, and the number of particles ( Frequency) and the center value of the circularity, the average circularity is calculated. The error between the value of the average circularity calculated by this calculation method and the average circularity calculated by directly using the circularity of each particle is very small and is substantially negligible. Therefore, in the present invention, the average circularity does not matter even if the value calculated at the same time as the measurement with the measuring device “FPIA-1000” is used. Therefore, this directly calculated value is used unless otherwise specified. .

In the measurement, 5 mg of toner is put in 10 ml of water in which about 0.1 mg of a surfactant is dissolved, and a dispersion is obtained by irradiating with ultrasonic waves (20 kHz, 50 W) for 5 minutes. The particle concentration in the dispersion is 5000. After adjusting with water so as to be ˜20,000 particles / μl, it is carried out by a measuring device, and the average circular shape of the particles whose equivalent circle diameter is 3 μm or more from the projected area S _i and the peripheral length L _{i of} each particle obtained Degree A _avg is obtained.

The reason why the circularity A _i is measured only for particles having an equivalent circle diameter of 3 μm or more in this measurement is that many external additives blended in the toner are included as particles having an equivalent circle diameter of less than 3 μm. This is because when the measurement object is expanded to less than 3 μm, the circularity A _i of the toner particles themselves cannot be accurately estimated due to the influence.

  When using the toner described above, the circular slicing characteristic value A (φ0.050) on the outer peripheral surface of the developing roller must be in the range of 0.8 to 2.4 μm.

  When a developing roller having such surface characteristics is used, unevenness of image density due to the difference in toner transportability, specifically the uniformity of the toner coat, particularly the good gloss when combined with the toner of the present invention. Therefore, the roughness observed in a particularly small area can be kept at a good level even when initially used for a long time and when it is continuously used over a long period of time.

  The developing roller used in the developing method and the image forming method of the present invention will be described by taking the two-layer developing roller 1 shown in FIG. 1 as an example.

  The developing roller 1 has an elastic body layer 12 on the outer peripheral surface of a columnar or hollow cylindrical substrate 11 having at least a conductive surface, and a surface layer 13 is formed on the outer peripheral surface of the elastic body layer 12. .

  The substrate 11 functions as an electrode for charging the developing roller 1 and a support member for the developing roller 1, and at least the surface thereof must be conductive. For example, aluminum, copper alloy, stainless steel, etc. It is made of a conductive material such as a metal or alloy, iron plated with chromium, nickel, or the like, or a synthetic resin. The substrate 11 is preferably in the range of usually an outer diameter of 4 to 10 mm.

  The elastic layer 12 contacts the photosensitive drum 21 with an appropriate nip width and nip pressure by the developing roller 1, and an electrostatic latent image formed on the surface of the photosensitive drum 21 by toner carried on the surface of the developing roller 1 is used as a toner image. When developing, the developing roller 1 is in uniform contact with the surface of the photosensitive drum 21, and the toner has appropriate hardness and electric resistance value in order to contribute to appropriate charging and development.

  The elastic body layer 12 is usually formed of a molded body of rubber material. As the raw rubber, various rubbers conventionally used for conductive rubber rollers can be used. Specifically, ethylene-propylene-diene copolymer rubber (EPDM), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR). ), Fluorine rubber, silicone rubber, epichlorohydrin rubber, hydride of NBR, polysulfide rubber, urethane rubber, etc., are used alone or in admixture of two or more.

  In particular, it is preferable to use silicone rubber because excellent setting performance can be obtained. Examples of the silicone rubber include polydimethylsiloxane, polymethyltrifluoropropylsiloxane, polymethylvinylsiloxane, polytrifluoropropylvinylsiloxane, polymethylphenylsiloxane, polyphenylvinylsiloxane, and copolymers of these polysiloxanes. These silicone rubbers are preferably those having an average degree of polymerization of 3000 to 15000.

  In the rubber material, various additives such as a conductive agent, a nonconductive filler, a crosslinking agent, a catalyst, and a dispersion accelerator are appropriately blended.

  Conductive agents include various conductive metals or alloys such as carbon black, graphite, aluminum, copper, tin, stainless steel, tin oxide, zinc oxide, indium oxide, titanium oxide, tin oxide antimony monoxide solid solution, tin oxide monoxide Various conductive metal oxides such as indium solid solution and fine powders such as insulating substances coated with these conductive materials can be used. Among these, carbon black can be obtained relatively easily and can impart good conductivity. As a dispersing means, a roll kneader, a Banbury mixer, a ball mill, a sand grinder, a paint shaker, or the like may be used as appropriate.

In addition, as a means for imparting conductivity to the rubber material, a conductive polymer compound can be used. For example, as a host polymer, polyacetylene, poly (p-phenylene), polypyrrole, polythiophene, poly (p-phenylene oxide), poly (p-phenylene sulfide), poly (p-ferene vinylene), poly (2,6- Dimethylphenylene oxide), poly (bisphenol-A-carbonate), polyvinylcarbazole, polydiacetylene, poly (N-methyl-4-vinylpyridine), polyaniline, polyquinoline, poly (phenylene ether sulfone), etc. AsF ₅ , I ₂ , Br ₂ , SO ₃ , Na, K, ClO ₄ , FeCl ₃ , F, Cl, Br, I, Kr ions, Li, TCNQ, and the like are used.

  Examples of the non-conductive filler include diatomaceous earth, quartz powder, dry silica, wet silica, titanium oxide, zinc oxide, aluminosilicate, calcium carbonate, and the like.

  There is no restriction | limiting in particular as a silica, A conventionally well-known thing can be used widely, For example, the anhydrous silicic acid by the dry method mentioned above, the hydrous silicic acid by a wet method, a synthetic silicate etc. can be used. The amount of silica contained in the elastic layer may be appropriately determined in order to obtain the hardness and other characteristics of the elastic layer, but in order to contribute to adhesiveness, 100 parts by mass of the silicone rubber component is used. On the other hand, the range of 10 to 120 parts by weight is desirable, and the range of 20 to 80 parts by weight is more preferable. If the amount used is less than 10 parts by weight, the contribution to the adhesion due to the addition of silica is hardly obtained, and if it exceeds 120 parts by weight, the elastic layer becomes too hard and the good properties of using silicone rubber are lost.

  As a crosslinking agent, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, dicumyl peroxide, t-butylperoxybenzoate, p-chlorobenzoylper Examples include oxides.

The elastic layer preferably has a volume resistivity of 10 ³ to 10 ¹⁰ Ω · cm when a DC voltage of 100 V is applied. For example, when carbon black is used as the conductive agent, 5 to 100 parts by weight is blended with 100 parts by weight of silicone rubber.

  The thickness of the elastic layer may be in the range of 0.5 to 6.0 mm, and preferably in the range of 1.0 to 5.0 mm. If the thickness is thicker than 0.5 mm, it is possible to ensure uniform nip pressure and nip width. On the other hand, even if the thickness is made thicker than 6.0 mm, not only the performance is not improved, but also the molding cost of the rubber material is increased, which is disadvantageous in terms of cost.

  As a method of providing the elastic layer 12 on the substrate 11, the elastic layer raw material is extruded into a tube shape and cured to obtain an elastic tube, cut into a predetermined length, and if necessary, an adhesive is applied in advance. The substrate 11 is press-fitted into the cutting tube, and the surface is polished so as to have a predetermined outer diameter. The elastic body material is injected and cured into a cavity of a cylindrical mold in which the substrate 11 is previously stored, and the substrate directly There is a method of forming the elastic body layer 12 on the surface 11 and polishing the surface if necessary, and the method for forming the elastic body layer 12 on the substrate 11 is not particularly limited.

  The surface layer 13 is not particularly limited, but polyamide resin, urethane resin, urea resin, and the like are particularly formed as a resin component from the viewpoint of self-film reinforcing property, toner charging property, and the like.

  As the urethane resin, for example, carbon black is blended in a polyurethane prepolymer, and the prepolymer is obtained by a crosslinking reaction, or a conductive material is blended in a polyol, and this polyol is polyisocyanate by a one-shot method. What was obtained by the method of making it react with a rice cake etc. is preferable.

  Examples of polyol components include polyols used in the production of general flexible polyurethane foams and urethane elastomers, such as polyether polyols having a polyhydroxyl group at the terminal, polyester polyols, and polyether polyester polyols that are copolymers of both. Polyolefin polyols such as polybutadiene polyol and polyisoprene polyol, and general polyols such as so-called polymer polyols obtained by polymerizing ethylenically unsaturated monomers in polyols can be used.

  In addition, as the isocyanate compound, polyisocyanate used in the production of general flexible polyurethane foam and urethane elastomer, that is, tolylene diisocyanate (TDI), crude TDI, 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, C2-C18 aliphatic polyisocyanate, C4-C15 alicyclic polyisocyanate, mixtures and modified products of these polyisocyanates, prepolymers obtained by partially reacting with polyols, etc. Is used.

  Usually, the polyol component and the polyisocyanate component are used by mixing the functional group OH and the functional group NCO in an equimolar ratio, but even if the mixing ratio of the polyisocyanate is lowered for the purpose of reducing the hardness of the elastic layer. I do not care.

  The urethane resin includes a one-pack type and a two-pack type, but an epoxy resin or a melamine resin may be used as a crosslinking agent as necessary.

  Polyamide resins include PA-6, PA-6 · 6, PA-6 · 10, PA-6 · 12, PA-11, PA-12, PA-12 · 12 There are condensed polyamides and the like, and alcohol-soluble ones or alcohol-solubilized ones are preferably used from the viewpoint of workability. For example, those obtained by adjusting the molecular weight of ternary copolymerized polyamide or quaternary copolymerized polyamide, or those obtained by methoxymethylating NH of the amide group of PA-6 or PA-12 to be soluble in alcohol or water.

  Urethane resin, polyamide resin, other modified resins, etc. can be used alone or in combination of two or more, and the toner charge amount suitable for the development system can be selected appropriately according to the system to be developed. Can be obtained.

  Various additives such as a conductive agent and a non-conductive filler are appropriately blended in the resin material used for the surface layer. From those exemplified above as additives that can be contained in the elastic layer, it can be selected according to the resin material of the main component. Moreover, the addition amount can be suitably determined according to the addition purpose.

  When adding carbon black, although depending on the resin component forming the surface layer, the amount is preferably 10 to 50 parts by mass with respect to 100 parts by mass of the resin component. For example, when a urethane resin is used, it is preferably 15 to 50 parts by mass, more preferably 20 to 40 parts by mass. The term “resin component” as used herein refers to a resin itself such as a resin, its monomer component, a curing agent component, a crosslinking agent component, or a component constituting it in the case of a blend of a urethane resin with a polyol, diisocyanate, or another resin. Based on the main component as a film forming component of the resin layer, additives such as a conductive agent and a non-conductive filler are not included.

  As a method for controlling the circular slicing characteristic value X (φM) on the surface of the developing roller, a method in which the surface is formed with an uneven shape in advance with the elastic layer 12 before the surface layer 13 is formed, or elastic particles are formed on the resin layer 13. There is a method of adding. In order to form irregularities on the surface of the elastic layer 12 in advance, there are a method of transferring the shape of the inner surface of the mold when the elastic layer 12 is formed, a method of polishing the surface of the elastic layer 12 to process the irregularities, and the like.

  As a means for forming the surface layer 13 on the surface of the elastic body layer 12, a method of applying a surface layer coating solution to the elastic body layer 12 is effectively employed. The resin component concentration in the coating solution is not particularly limited, and may be appropriately adjusted according to the film thickness to be formed. However, the resin component concentration is 8% by mass or more from the dispersibility and stability of carbon black in the coating solution. It is preferable that The solvent for adjusting the coating liquid may be any solvent as long as it can dissolve the resin, for example, lower alcohols such as methanol, ethanol and isopropanol, ketones such as methyl ethyl ketone, cyclohexane, toluene, Hydrocarbons such as xylene are preferred. In order to obtain a good film forming property by a drying process after coating, it is preferable to use these mixed solvents.

  Moreover, you may add a dispersing agent to this coating liquid in order to improve the dispersion stability of carbon black.

  Application can be performed by a spray method, a roll coater method, a dipping method, or the like. In the dipping method, the roller on which the elastic layer 12 has been formed is immersed in the coating solution at room temperature for 5 seconds to 3 minutes, preferably 10 seconds to 30 seconds, and then pulled up and dried. Further, in the case of the spray method, the resin concentration in the coating solution can be set higher than that of the dipping method, and for example, it is possible to use a solution adjusted to a concentration of 30% or more. In any case, the resin concentration, coating method, and coating conditions may be set as appropriate so that a desired film thickness can be obtained.

  The thickness of the surface layer 13 is not particularly limited and may be appropriately selected, but is preferably 5 to 100 μm, more preferably 7 to 30 μm.

  In the present invention, the developing roller has a circular slicing characteristic value X (φ0.050) at a diameter of 0.050 mm in the range of 0.8 to 2.4 μm together with the use of the toner. ,is important.

<Measuring method of circular slicing characteristic value X (φM)>
Using a three-dimensional optical profiler system (trade name: NewView 5010, manufactured by ZYGO), the surface of the developing roller is observed with a 50 × objective lens, and an area of 0.1 mm square or more can be obtained at a scanning height of 200 μm. Filled plot. The data of the plot is derived from the surface of the best-fit cylinder with respect to the deflection due to the roller shape, and numerical value correction processing is performed. Write a circle with a diameter of Mmm on the corrected plot (circular slicing), and along the circle, the arithmetic average height of the cross-section curve from the average of the absolute value of the cross-section curve f (x) at the entire circumference, that is, πMmm Is determined as a circular slicing characteristic value X (φM). The circular slicing characteristic value with a diameter of 0.050 mm is expressed as X (φ0.050), and hereinafter, unless otherwise specified, “characteristic value” means “circular slicing characteristic value”, simply X (ΦM), X (φ0.050), etc.

  By setting X (φ0.050) in the range of 0.8 to 2.4 μm, the developing roller has sufficient toner transportability, and unevenness of image density (particularly in a minute region) due to non-uniformity of toner carrying. The image with good gloss and good fixability is exhibited. Furthermore, a stable image similar to the initial stage can be maintained even during continuous use over a long period of time. When X (φ0.050) is less than 0.8 μm, it is difficult to stably obtain sufficient toner transportability. When X (φ0.050) exceeds 2.4 μm, the change in the developing roller surface becomes large during continuous use over a long period of time, and the image quality is likely to change. By setting X (φ0.050) in the above range, the image quality is stabilized by suppressing the roughness in a minute region. It can be considered that stabilizing the characteristic value at a radius of 0.050 mm is visually beautiful for humans. Although it is sensual, the image quality is moist, and when the gloss is high as in the present invention, it is possible to obtain a high-quality texture such as offset printing. Although depending on the combination with the toner characteristic value, X (φ0.050) is more preferably in the range of 1.0 to 2.2 μm from the viewpoint of image stability during continuous use.

Further, as a developing roller, a circular slicing characteristic value X (φ0.050) with a diameter of 0.050 mm was measured at three locations along the circumference at five locations in the longitudinal direction (total of 15 locations). It is preferable that the following formula 1 is satisfied among the average value X _{max of} the three measured values, the average value X _{min of} the smaller three measured values, and the average value X _avg of all the measured values. In the following, the left side of Equation 1 below may be referred to as “Z”.
(X _max −X _min ) / X _avg ≦ 0.5 (Formula 1)

  By satisfying Expression 1, the toner transportability on the developing roller is stabilized, and the uniformity of the toner coat in a wide range over the entire surface of the developing roller can be obtained. In other words, the density unevenness of the image (especially, the roughness in a minute region) is reduced, and an image having good gloss and fixing properties can be stably obtained over the entire image on the transfer material. When Expression 1 is not satisfied, that is, when the left side of Expression 1 is larger than 0.5, in the actual image on the transfer material, the level of shading unevenness (especially, roughness in a minute region) is reduced at the developing roller pitch. Different parts occur and the impression of the entire image is not preferred. In addition, although the value of Formula 1 is so preferable that it is small, if the left side of Formula 1 is 0.5 or less, coexistence with a production side will be easy and the image quality obtained will be sufficient.

Further, when the developing roller measures the circular slicing characteristic value X (φM) every 0.010 mm concentrically with a diameter of 0.050 to 0.100 mm, the following formula 2 is calculated between the adjacent values. It is preferable that it is satisfied.
0.8 ≦ X (φM) / X (φM ± 0.010) ≦ 1.25 (Formula 2)

  Between the photosensitive drum 21 and the developing roller 25, a circumferential speed difference is set such that the peripheral speed of the developing roller is 100% (constant speed) to 200% (double) with respect to the peripheral speed of the photosensitive drum. (See A and B in FIG. 2). In the case of a color laser printer, the peripheral speed difference may be set individually depending on the color. However, basically, a good image can be obtained by setting X (φ0.050) in the range of 0.8 to 2.4 μm. However, by satisfying the relationship of Formula 2, the photosensitive drum Regardless of the peripheral speed difference between the developing roller 25 and the developing roller 25, a good image can be obtained.

  In the case where the relationship of Expression 2 is not satisfied, when the difference in the peripheral speed between the photosensitive drum 21 and the developing roller 25 becomes large, there may be some confirmation of unevenness in the density of the image (particularly, roughness in a minute region).

  Further, when elastic particles are added to the surface layer 13 to form a concavo-convex shape on the surface of the developing roller, the elastic particles contained in the surface layer are aggregate characteristics measured by centrifugal sedimentation analysis and have a Stokes equivalent diameter. It is calculated from the most frequent value (Dst (nm)) of the distribution curve, the half-value width of the distribution curve, and the difference between two large and small Stokes equivalent diameters (ΔD50 (nm)) corresponding to 50% frequency of the most frequent value. It is preferable that the value of ΔD50 / Dst is 0.60 or less.

  When the value of ΔD50 / Dst is 0.60 or less, the circular slicing characteristic value X (φM) can be easily controlled, and the effects of the present invention can be obtained stably and easily. In other words, even when combined with a toner with good glossiness used in the present invention with sufficient toner transportability, the density unevenness of the image (particularly, roughness in minute areas) due to the difference in toner coat uniformity is reduced. An image with good gloss and good fixability can be obtained. Further, even during continuous use over a long period of time, a stable image similar to the initial stage can be maintained. Even when the value of ΔD50 / Dst is larger than 0.60, a sufficient effect can be obtained if the requirement of the present invention is satisfied. However, when the value of ΔD50 / Dst is 0.60 or less, the degree of the effect In view of the degree of freedom of production, etc., it is preferable. Note that the smaller the value of ΔD50 / Dst, the better the performance, but for example, when using particles after classification, a balance with the yield is necessary. Is not good. Depending on the type of particles used and the means, it may be selected as appropriate.

<Measurement of particle size and distribution by aggregate characteristics of particles by centrifugal sedimentation analysis>
Measuring device: High-speed disk centrifuge ultrafine particle size analyzer "BI-DCP" (trade name, manufactured by BROOKHAVGN INSTRUMENTS CORPORATION)
Measurement sample: A particle sample is put into a 40% by volume ethyl glycol aqueous solution and sufficiently dispersed with an ultrasonic homogenizer to obtain a dispersion, which is used as a sample.
Measurement method: Set the rotation speed of the centrifugal disk to 600 rpm, add 10.0 ml of spin solution (pure water, 24 ° C.), and then inject 1.0 ml of buffer solution (40% by volume ethyl glycol aqueous solution, 24 ° C.). To do. Next, 0.5 ml of a dispersion of particles at 24 ° C. is injected, and measurement is started. The Stokes equivalent diameter (D) corresponding to the time t is calculated by the following formula 4 from the elapsed time t after the injection of the particle dispersion and the absorbance distribution curve.

式４において、ηは溶媒の粘度、ωはディスク回転数、Δρは粒子と溶媒の密度差、Ｒｉは粒子分散液注入点の半径、Ｒｄは吸光度測定点までの半径である。分布曲線における最多頻度値でのストークス相当径をＤｓｔ（ｎｍ）とし、最多頻度値の５０％頻度に相当する大小２点のストークス相当径の差（半値幅）をΔＤ５０（ｎｍ）とする。

In Equation 4, η is the viscosity of the solvent, ω is the disk rotational speed, Δρ is the density difference between the particles and the solvent, Ri is the radius of the particle dispersion injection point, and Rd is the radius to the absorbance measurement point. The Stokes equivalent diameter at the most frequent value in the distribution curve is Dst (nm), and the difference (half-value width) between two large and small Stokes equivalent diameters corresponding to 50% frequency of the most frequent value is ΔD50 (nm).

  The particles added to the resin layer 13 are preferably in the above range, but are not particularly limited and can be freely selected. When the contact development method is used as in the present invention, density unevenness on the image is reduced, and therefore it is preferable to use flexible particles.

As described above, a developing method that includes a developing roller that carries toner while being in contact with or pressed against a photosensitive drum, and the developing roller applies toner to the photosensitive drum so that the latent image is visualized as a toner image. The toner has toner particles containing at least a binder resin and a colorant, and the loss tangent (tan δ) of the toner has a minimum value 1 and a maximum value 1 at 70 to 110 ° C .; The toner has a maximum value of 2 at 140 to 200 ° C., and the loss elastic modulus G ″ (140 ° C.) at 140 ° C. of the toner is 1.0 × 10 ^{4 to} 2.0 × 10 ⁵ dN / m ^2. When the circular slicing characteristic value X (φ0.050) on the outer peripheral surface of the roller is in the range of 0.8 to 2.4 μm, the image has less unevenness of the image and has good gloss and good fixability. Get It is, even during continuous use over a long, consisting developing method capable of sustaining the initial same stable image, and an image forming method.

  Examples of the present invention are specifically shown below, but are not limited thereto. In addition, unless otherwise indicated below, a part represents a mass part.

Reference Example 1 (Production of Toner 1)
3 parts of tricalcium phosphate is added to 900 parts of ion-exchanged water heated to 70 ° C., and stirred at 10,000 rpm using a TK homomixer (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.). A medium was obtained. On the other hand, 80 parts of styrene, 15 parts of n-butyl acrylate, 0.3 part of 1,3-butanediol dimethacrylate, saturated polyester resin (polycondensate of propylene oxide-modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4) 4.5 parts and C.I. I. 10 parts of Pigment Blue 15: 3 were uniformly dispersed and mixed using a dispersion mixer “Attritor” (trade name, Mitsui Miike Chemical Co., Ltd.), and then this monomer mixture was heated to 70 ° C. In addition, 9 parts of an ester wax mainly composed of stearyl stearate (maximum endothermic peak 67 ° C. in DSC measurement) was added, mixed and dissolved, and further, a polymerization initiator 2,2′-azobis-2-methylbutyronitrile ( 3 parts) were dissolved. This was put into the above aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) in an N ₂ atmosphere at 70 ° C., and dispersed and granulated. Subsequently, a mixture of 5 parts of styrene and 1 part of an aluminum salicylate compound (trade name: Bontron E-88, manufactured by Orient Chemical Co., Ltd.) was added thereto, and the mixture was further stirred at 10,000 rpm for 1 minute.

  Thereafter, the mixture was reacted at 70 ° C. for 6 hours while stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  The particles were dried at 40 ° C. for 12 hours to obtain colored particles (toner particles) having a weight average particle size of 7.6 μm.

100 parts of the toner particles and 0.7 parts of hydrophobic silica fine powder (BET value 200 m ² / g, primary particle size 12 nm) treated with silicone oil are mixed with a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) Toner 1 was obtained.

Reference Example 2 (Production of Toner 2)
3 parts of tricalcium phosphate was added to 900 parts of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (trade name) to obtain an aqueous medium. On the other hand, 80 parts of styrene, 15 parts of n-butyl acrylate, 5 parts of saturated polyester resin (polycondensation product of propylene oxide-modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4) , 1 part of an aluminum salicylate compound (trade name: Bontron E-88), C.I. I. Pigment Blue 15: 3 10 parts and 14 parts of ester wax mainly composed of behenyl behenate (maximum endothermic peak 72 ° C. in DSC measurement) were uniformly dispersed and mixed using a mixing disperser “Attritor” (trade name), Next, 4 parts of the polymerization initiator lauroyl peroxide (10 hours half-life 62 ° C.) was dissolved while the monomer composition was heated to 60 ° C. This was put into the above aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) in an N ₂ atmosphere at 60 ° C., and dispersed and granulated. Next, a mixture of 5 parts of styrene and 1.7 parts of an aluminum salicylate compound (trade name: Bontron E-88) was added thereto, and the mixture was further stirred at 10,000 rpm for 1 minute.

  Thereafter, the mixture was reacted at 60 ° C. for 6 hours while stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  The particles were dried at 45 ° C. for 12 hours to obtain colored particles (toner particles) having a weight average particle diameter of 7.7 μm.

Toner 2 was obtained by mixing 100 parts of the toner particles and 1.3 parts of hydrophobic silica fine powder (BET value 200 m ² / g, primary particle size 12 nm) treated with silicone oil using a Henschel mixer.

Reference Example 3 (Production of Toner 3)
3 parts of tricalcium phosphate was added to 900 parts of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (trade name) to obtain an aqueous medium. On the other hand, 86 parts of styrene, 14 parts of n-butyl acrylate, 0.5 part of divinylbenzene, saturated polyester resin (polycondensate of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4) 5 parts, aluminum salicylate compound (trade name: Bontron E-88) 1 part, C.I. I. Pigment Blue 15: 3 10 parts and ester wax mainly composed of stearyl stearate (maximum endothermic peak 67 ° C. in DSC measurement) 1.5 parts are uniformly dispersed and mixed using a mixing disperser “Attritor” (trade name) Then, 4 parts of the polymerization initiator lauroyl peroxide (10 hours half-life 62 ° C.) was dissolved while the monomer composition was heated to 60 ° C. This was put into the above aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) in an N ₂ atmosphere at 60 ° C., and dispersed and granulated. Next, a mixture of 5 parts of toluene and 2 parts of an aluminum salicylate compound (trade name: Bontron E-88) was added thereto, and the mixture was further stirred at 10,000 rpm for 1 minute.

  Thereafter, the mixture was reacted at 60 ° C. for 6 hours while stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  The particles were dried at 45 ° C. for 12 hours to obtain colored particles (toner particles) having a weight average particle diameter of 7.7 μm.

Toner 3 was obtained by mixing 100 parts of the toner particles and 0.7 part of titanium oxide fine powder (BET value 150 m ² / g, primary particle size 30 nm) with a Henschel mixer.

Reference Example 4 (Production of Toner 4)
3 parts of tricalcium phosphate was added to 900 parts of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (trade name) to obtain an aqueous medium. On the other hand, 83 parts of styrene, 17 parts of n-butyl acrylate, 5 parts of saturated polyester resin (polycondensate of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4) , C.I. I. 10 parts of Pigment Blue 15: 3 and 22 parts of Fischer-Tropsch wax FT-100 (trade name, manufactured by Nippon Seiki Co., Ltd., maximum endothermic peak 88 ° C. in DSC measurement) were used with a mixing disperser “Attritor” (trade name). Then, 4 parts of the polymerization initiator lauroyl peroxide (10 hours half-life 62 ° C.) was dissolved while the monomer composition was heated to 60 ° C. This was put into the above aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) in an N ₂ atmosphere at 60 ° C., and dispersed and granulated.

  Then, it was made to react at 60 degreeC for 6 hours, stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  The particles were dried at 45 ° C. for 12 hours to obtain colored particles having a weight average particle diameter of 7.7 μm.

  2 parts of aluminum salicylate compound (trade name: Bontron E-88) are mixed with 137 parts of the colored particles in a blender, melt-kneaded with a biaxial extruder heated to 110 ° C., and the cooled kneaded product is hammered. The coarsely pulverized product was finely pulverized with a jet mill collision type jet mill (trade name, manufactured by Nippon Pneumatic Industry Co., Ltd.). The obtained finely pulverized product was classified to obtain toner particles having a weight average particle diameter of 7.7 μm.

Toner 4 was obtained by mixing 100 parts of the toner particles and 0.7 part of titanium oxide fine powder (BET value 150 m ² / g, primary particle size 30 nm) with a Henschel mixer.

Reference Example 5 (Production of Toner 5)
3 parts of tricalcium phosphate was added to 900 parts of ion-exchanged water heated to 70 ° C. and stirred at 10,000 rpm using a TK homomixer (trade name) to obtain an aqueous medium. On the other hand, 91 parts of styrene, 4 parts of n-butyl acrylate, 0.3 part of divinylbenzene, saturated polyester resin (polycondensate of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mn = 17000, Mw / Mn = 2.4) 4.5 parts and C.I. I. Pigment Blue 15: 3 10 parts were uniformly dispersed and mixed using a mixing and dispersing machine “Attritor” (trade name), and then this monomer composition was heated to 70 ° C. while stearic acid was added. 9 parts of ester wax mainly composed of stearyl (maximum endothermic peak 67 ° C. in DSC measurement) was added and mixed, and further polymerization initiator 2,2′-azobis-2-methylbutyronitrile (10 hour half-life temperature 67 ° C.) 3 parts were dissolved. This was put into the above aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) in an N ₂ atmosphere at 70 ° C., and dispersed and granulated. Next, 5 parts of styrene was added thereto, and the mixture was further stirred at 10,000 rpm for 1 minute.

  Thereafter, the mixture was reacted at 70 ° C. for 6 hours while stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  The particles were dried at 40 ° C. for 12 hours to obtain colored particles (toner particles) having a weight average particle size of 7.6 μm.

Toner 5 was obtained by mixing 100 parts of the toner particles and 1.3 parts of hydrophobic silica fine powder (BET value 200 m ² / g, primary particle size 12 nm) treated with silicone oil using a Henschel mixer.

Reference Example 6 (Production of Toner 6)
3 parts of tricalcium phosphate was added to 900 parts of ion-exchanged water heated to 73 ° C., and stirred at 10,000 rpm using a TK homomixer (trade name) to obtain an aqueous medium. On the other hand, 80 parts of styrene, 20 parts of n-butyl acrylate, 0.5 part of divinylbenzene, 2.1 parts of ethylene glycol diacrylate, saturated polyester resin (polycondensate of propylene oxide-modified bisphenol A and isophthalic acid, Tg = 62 C., Mn = 17000, Mw / Mn = 2.4) 1.0 part, 1 part of aluminum salicylate compound (trade name) and C.I. I. 10 parts of Pigment Blue 15: 3 were uniformly dispersed and mixed using a mixing and dispersing machine “Attritor” (trade name), and then the monomer composition was heated to 73 ° C. while stearic acid was added. 0.7 parts of an ester wax mainly composed of stearyl (maximum endothermic peak 67 ° C. in DSC measurement) was added and dissolved, and further a polymerization initiator 2,2′-azobis-2-methylbutyronitrile (10-hour half-life temperature) 67 parts) was dissolved. This was put into the above-mentioned aqueous medium, stirred at 10,000 rpm for 7 minutes with a TK homomixer (trade name) at 73 ° C. in an N ₂ atmosphere, and dispersed and granulated.

  Thereafter, the mixture was reacted at 73 ° C. for 6 hours while stirring with a paddle stirring blade. Thereafter, the reaction temperature was raised to 80 ° C. and stirring was continued for 4 hours. After completion of the reaction, hydrochloric acid was added to the suspension cooled to room temperature (25 ° C.) to dissolve the calcium phosphate salt, followed by filtration and washing with water to obtain wet colored particles.

  Next, the particles were dried at 40 ° C. for 12 hours to obtain colored particles (toner particles) having a weight average particle size of 7.0 μm.

Toner 6 was obtained by mixing 100 parts of the toner particles and 0.7 part of titanium oxide fine powder (BET value 150 m ² / g, primary particle size 30 nm) with a Henschel mixer.

  Table 1 shows the physical properties of Toners 1 to 6 prepared in Reference Examples 1 to 6.

Reference Example 7 (Production of raw material elastic roller)
The raw material elastic body roller for forming the surface layer was produced as follows.

(Shaft core)
An adhesive was applied to the outer peripheral surface of a SUS rod subjected to φ8 mm nickel plating and baked to use as a shaft core.

(Elastic layer material)
A polysiloxane mixture of a linear polydimethylsiloxane having a terminal vinyl group blocked, a block polymer composed of a branched polysiloxane segment having one vinyl group and a linear oil segment having a bifunctional dimethylsiloxane, Silica powder (trade name: manufactured by Nippon Aerosil Co., Ltd.) is added to 100 parts of an addition-type silicone rubber composition obtained by adding and mixing an organosiloxane having two or more silicon-bonded hydrogen atoms in the molecule and a platinum catalyst. Aerosil 130), 15 parts, quartz powder (manufactured by US Silica Company, trade name: Min-U-Sil 15) and 20 parts of conductive carbon black are added and mixed to form an elastic body which is a liquid rubber compound. A layer raw material was obtained.

(Production of raw material elastic roller)
The shaft core is placed in a mold, the elastic layer raw material is injected into the formed cavity, the mold is heated at 120 ° C. for 10 minutes, cooled, demolded, and further heated at 200 ° C. for 30 minutes. The raw material elastic body roller which consists of a 3 mm-thick elastic body layer (silicone rubber layer) was produced by heating for a minute and curing.

Reference Example 8 (Manufacture of developing roller 1)
Isocyanate “Coronate L” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) 14 parts (solid content) as a curing agent for 100 parts (as solid content) of polyol “Nipporan 5033” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd.) And 30 parts of carbon black “Toka Black # 7360SB” (trade name, manufactured by Tokai Carbon Co., Ltd.), and further, Particle A (polyurethane particles “Negami Kogyo Co., Ltd.” “Art Pearl C400 Transparent” (trade name) ) With 100ATP type turbo flex (trade name, manufactured by Hosokawa Micron Corporation) on the fine powder side classified at a rotational speed of 4300 rpm and obtained on the coarse powder side by classification at a rotational speed of 4700 rpm) 15 parts Add methyl ethyl ketone so that the solid content is 30% and stir well to mix uniformly. And adjusted to a solution to prepare a surface layer coating solution. The raw material elastic body roller obtained in Reference Example 7 was dipped in this coating solution and coated, then pulled up and dried, and heat treated at 140 ° C. for 40 minutes to form a surface layer having a thickness of about 16 μm as an elastic body. The developing roller 1 provided on the outer periphery of the layer was produced.

Reference Examples 9 to 16 (production of developing rollers 2 to 9)
Developing rollers 2 to 9 were produced in the same manner as in Reference Example 8 (production of developing roller 1) except that the particles shown in Table 2 were used instead of the urethane particles A in the amounts shown in Table 3.

  The characteristics of the developing rollers 1 to 9 produced in Reference Examples 8 to 16 are shown in Table 3 together with the type and amount of fine particles arranged on the surface layer.

Example 1
As an image forming apparatus, an organic photoreceptor digital printer “LBP5500” (trade name) using a laser beam manufactured by Canon Inc. was prepared. This “LBP5500” (trade name) is a tandem type color printer that includes four toner color cartridges, each of which is provided with image writing means (laser beam), and a transfer belt. The standard image creation capability is 17 sheets / minute for A4 size.

  The cartridge has a photosensitive drum, a charging roller as a charging unit (a Kapton (trademark) sheet is provided in contact with the photosensitive drum for cleaning the charging roller), and a developing roller as a developing unit. Further, a supply roller for supplying toner to the developing roller and scraping the return toner that has not been used for forming the toner image remaining on the developing roller to frictionally charge the toner is provided. A developer regulating blade is provided in contact with the developing roller to make the amount of the toner constant and apply frictional charging (corresponding to the one-component contact developing system). The developing roller is in contact with the photosensitive drum.

  Further, the cartridge is provided with a cleaning blade that comes into contact with the photosensitive drum and wipes off toner remaining on the photosensitive drum, transfer material waste, etc. on the photosensitive drum to remove the charge remaining on the photosensitive drum before charging by the charging roller. Pre-exposure means is provided.

  The apparatus was processed so that the output speed of LBP5500 (trade name) was increased to 22 sheets / minute of A4 paper, and the developing roller 1 produced in Reference Example 8 was incorporated as the developing roller of the cyan color cartridge, and the cyan toner was used in Reference Example 1 as the cyan toner. The prepared toner 1 was filled, and the magenta, yellow, and black cartridges were placed in their respective rations with the toner removed and the remaining toner detection mechanism disabled.

  Using the image forming apparatus modified as described above, a standard chart (FIG. 5) was continuously output, a predetermined number of sheets were output according to the following evaluation items, and evaluated according to the following criteria. It should be noted that the 101st and 6002th images were output as full-color solid images, and the 102nd and 6003rd images were output as full-color halftone solid images.

(Glossy)
Using LETTER-sized plain paper “XEROX 4024” (trade name, manufactured by Nippon Xerox Co., Ltd., 75 g / m ² ) as the transfer material, on the 100th sheet (initial) and the 6000th sheet (during continuous use over a long period of time) For the output image, the glossiness of each of the obtained five solid image portions was measured at a incident angle of 75 degrees using a gloss meter “PG-3G” (trade name, manufactured by Nippon Denshoku Industries Co., Ltd.) The average value was defined as the image glossiness of the transfer material.
A: The glossiness is 12.5 or more for both the 100th and 6000th sheets, and all measured values are 11.0 or more.
A: The glossiness of both the 100th sheet and the 6000th sheet is 12.5 or more, and all measured values are 10.0 or more.
(Triangle | delta): Glossiness is 12.5 or more on the 100th sheet, 12.0 or more on the 6000th sheet, and all measured values are 10.0 or more.
X: The glossiness is less than 12.5 for the 100th sheet or less than 12.0 for the 6000th sheet, or all measured values include less than 10.0.

(Image rubbing property)
A4 size plain paper “Sanichi 牌 double stamped paper (neutral)” (trade name, manufactured by Sanichi 牌 Stamped Paper Co., Ltd., 70 g / m ² ) is used as the transfer material. The five solid image portions of the output image were rubbed five times with sylbon paper applied with a load of 50 g / cm ² , and the arithmetic average value of the reduction rate of the image density due to the rubbing was obtained. The image density was measured by a “Macbeth reflection densitometer” (trade name, manufactured by Macbeth Co., Ltd.).
A: Density reduction rate is less than 2%.
○: Density decrease rate is 2% or more and less than 5%.
Δ: Density reduction rate of 5% or more and less than 10%.
X: Concentration reduction rate of 10% or more.

(Uneven density)
LETTER-sized plain paper “XEROX 4024 paper” (product name) is used as the transfer material, and the solid image (101st sheet, 6002th sheet) and halftone image (102th sheet, 6003th sheet) are uniform throughout the image area. Eye) is output, and the uneven density (gray in a minute area) appearing in the obtained image is visually observed by five inspectors, and during initial use (101st sheet and 102nd sheet) and during continuous use over a long period (6002) The following standards were evaluated for each of the first sheet and the 6003th sheet). Then, the evaluation results of five inspectors were ranked, and the median value (third evaluation) was set as the evaluation for the sample.
A: Unevenness of shading (gray in a minute area) is not noticeable in both solid images and halftone images, and is good.
◯: Light and shade unevenness (gray in a minute area) is slightly noticeable in a solid image but at a level that is not a problem, and is not noticeable in a halftone image and is good.
Δ: Light and dark unevenness (gray in a minute area) can be seen slightly in both solid images and halftone images, but there is no problem.
X: Density unevenness (gray in a minute area) is observed for both solid images and halftone images, and at least for solid images, it is conspicuous and the impression is poor.

(Concentration uniformity)
The density uniformity of the entire image area on the transfer material of the 102nd halftone image used for the evaluation of the uneven density was visually evaluated. In addition, the rank which 3 or more people pointed out in 5 inspectors was made into the evaluation of the said sample.
○: No shading unevenness (gray in a minute area) is felt in the entire image area.
(Triangle | delta): The shading unevenness (grayness in a micro area | region) is somewhat felt in the whole image area | region.
X: Density unevenness (gray in a minute area) is observed in the entire image area, and the density itself is non-uniform.

(Comprehensive evaluation)
The results of the above evaluations (glossiness, image rubbing property, shading unevenness, density uniformity) were integrated, and comprehensively evaluated according to the following criteria.
A: Glossiness A, image rubbing ability A, density unevenness A, density uniformity A.
○: Glossiness ○ or higher, image rubbing property ○ or higher, density unevenness ○ or higher, density uniformity Δ or higher Δ: Glossiness Δ or higher, image rubbing property Δ or higher, density unevenness Δ or higher, density uniformity Δ or higher, There are ◎ in any of glossiness, image rubbing property, and shading unevenness.
X: There exists x in any of glossiness, image rubbing property, density unevenness, and density uniformity.

Examples 2-9, Comparative Examples 1-8
Example 1 except that toners 1 to 6 obtained in Reference Examples 1 to 6 were used as toners, and developing rollers 2 to 9 produced in Reference Examples 9 to 16 were used as developing rollers in the combinations shown in Table 4. Thus, glossiness, image rubbing property, density unevenness and density uniformity were evaluated, and comprehensive evaluation was performed from these results.

  Table 4 shows the evaluation results together with the toners and developing rollers used in the above examples and comparative examples.

  In Examples 1 to 9, there is no problem in any performance of glossiness, image rubbing property, density unevenness, density uniformity, among which Examples 1, 2 and 4 to 7 give good results, Examples 2 and 4 were particularly good.

  If any of the toner and the developing roller is out of the conditions of the present invention,

It is sectional drawing which shows an example of the elastic roller of this invention typically. It is explanatory drawing which shows an example of the image forming apparatus which can be used for the image development method and image forming method of this invention. It is a measurement figure with respect to temperature of the storage elastic modulus G 'and loss elastic modulus G "of the toner of the present invention. It is a measurement figure with respect to the temperature of the loss tangent (tan δ) of the toner of the present invention. It is a standard chart used for evaluation of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing roller 2 Developing apparatus 3 Image forming apparatus 11 Shaft core body 12 Elastic body layer 13 Surface layer 21 Photosensitive drum 22 Charging roller 23 Laser beam 25 Developing roller 26 Supply roller 27 Elastic blade 28 Toner 29 Transfer roller 30 Cleaning blade 31 Waste toner Container 32 Fixing device 33 Transfer material 34 Developer container

Claims (7)

To the electrostatic latent image formed on the latent image carrier, toner is applied in a state where the developing roller carrying the toner is in contact with or pressed against the latent image carrier, and the electrostatic latent image is used as a toner image. In the developing method to be visualized,
The toner has toner particles containing at least a binder resin and a colorant, and has a loss tangent (tan δ) of 70 to 110 ° C. in a dynamic viscoelastic property measured at a frequency of 6.28 rad / sec. It has a minimum value and a maximum value in the temperature range, a maximum value in the temperature range of 140 to 200 ° C., and a loss elastic modulus G ″ (140 ° C.) at 140 ° C. of 1.0 × 10 ⁴ to 2 0.0 × 10 ⁵ dN / m ² ,
In addition, the developing roller draws a circle having a diameter of 0.050 mm on the outer peripheral surface, and the circular slicing characteristic value X (φ0.050) obtained along the circle is in the range of 0.8 to 2.4 μm. The developing method characterized by the above-mentioned. The developing roller measures the circular slicing characteristic value X (φ0.050) with a diameter of 0.050 mm at five locations in the longitudinal direction and three locations along the circumference (total of 15 locations). measurements of three mean value X _max, between the average value X _avg of the smaller measured values of three mean value X _min and all measurements of, claim 1 is to satisfy the following formula 1 Development method.
(X _max −X _min ) / X _avg ≦ 0.5 (Formula 1) When the developing roller measures the circular slicing characteristic value X (φM) every 0.010 mm concentrically between 0.050 and 0.100 mm in diameter, the following formula 2 is satisfied between those adjacent values: The developing method according to claim 1, wherein the developing method is one.
0.8 ≦ X (φM) / X (φM ± 0.010) ≦ 1.25 (Formula 2) In the developing roller, elastic particles are blended on the outer peripheral surface, and the maximum frequency Stokes equivalent diameter Dst in the distribution curve of the Stokes equivalent diameter measured by the centrifugal sedimentation analysis method and the half-value width ΔD50 with respect to the Dst The developing method according to claim 1, which is satisfactory.
ΔD50 / Dst ≦ 0.60 (Formula 3)   The developing method according to claim 1, wherein the main component of the binder resin contained in the toner particles is a vinyl copolymer. The developing method according to claim 1, wherein the average circularity A _{avg of the} toner is 0.960 to 0.995.   7. An image forming method, wherein the toner image formed on the latent image carrier is transferred to a transfer material and then fixed using the developing method according to claim 1.

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