JP2009205034A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which scattering of fine toner is prevented even in long-term use and demands for high definition and high image quality is sufficiently satisfied. <P>SOLUTION: In the image forming method in which an electrostatic-charged-image carrier 101 for carrying an electrostatic charged image is charged, and an electrostatic charged image is formed on the charged carrier and then developed with toner on a developing sleeve 102, at least the outermost face of the developing sleeve is covered with an Ni plate containing Tungsten W, the toner contains at least magnetic substance in the range of 20.0 mass% to 60.0 mass%, and the magnetic substance contains Mg in the range of 0.20 mass% to 3.00 mass%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an image forming method for developing an electrostatic image formed by a recording method such as an electrophotographic method, an electrostatic recording method, a magnetic recording method, and a toner jet recording method using toner.

  As an electrophotographic method, a photoconductive material is generally used to form an electric latent image (electrostatic latent image) on an electrostatic charge image carrier by various means, and then the latent image is formed using toner. The toner image is developed and transferred onto a transfer material such as paper as necessary.

  Thereafter, fixing is performed by heating, pressurizing, heating / pressurizing, or solvent vapor to obtain a subject, and the toner remaining without being transferred onto the electrostatic image bearing member is cleaned by various methods, and the above steps are repeated. It is what

  Of these, the one-component development method is preferably used as the development method because it has a simple structure with few troubles, long life, and easy maintenance. This method increases the chance of contact between the developing sleeve and the toner by thinly applying the magnetic toner on the developing sleeve, and enables sufficient frictional charging. In addition, the magnetic toner is supported by the magnetic force, and the magnet and the toner are relatively moved so that the aggregation between the toner particles is released and the image is excellently rubbed with the developing sleeve. Is. For this reason, the individual performance and interaction between the magnetic toner and the developing sleeve greatly affect the obtained image.

  By the way, in recent years, electrophotographic apparatuses have been strictly pursued for smaller size, lighter weight, higher speed, and higher reliability.

  For example, it is beginning to be used not only as a general-purpose copying machine for copying an original document but also as a high-definition image copy such as a digital printer or graphic design as a computer output. Furthermore, it has begun to be used for light printing (print-on-demand applications that allow high-mix, low-volume printing from document editing to copying and bookbinding on a personal computer) that require higher reliability. For this reason, higher image quality and higher image quality are demanded, and it is required that there is no toner scattering and slight toner leakage that have not been a problem in the past.

  Furthermore, as market needs, characteristics such as long life and maintenance-freeness are emphasized in addition to high image quality.

  In response to these requirements, for the developing sleeve, electroless Ni—P, Ni—B, Pd—P (Ni is nickel, P is phosphorus, B is boron, and Pd is palladium on the surface of the aluminum alloy substrate. Or a developing sleeve provided with a plating layer of electroless Cr (chromium) plating (Patent Document 1). As a result, this is sufficiently achieved for a long life, but it is still insufficient for the recent demands for high definition and high image quality.

  On the other hand, as an approach from the toner, high image quality is achieved by controlling the wettability of the magnetic toner to a specific solvent and controlling the atomic concentration of a specific metal element present on the outermost surface of the magnetic material. (Patent Document 2). This toner also has a sufficient effect for image quality such as a character image, but is still not sufficient for images in graphics and light printing applications.

  Further, there is a description of a system excellent in developability and durability by combining a developing sleeve having an electroless Ni-P, Ni-B or electroless Cr plating layer with a toner using a magnetic material having a specific metal element. Yes (Patent Document 3). As a result, toner scattering is improved to some extent, but toner scattering tends to occur particularly in a situation where the chargeability is slightly lowered as in the latter half of the durability. As a result, an image defect such as fogging may occur on the image although it is slight.

  As described above, there is still no means that can sufficiently satisfy the demands for high definition and high image quality in graphics and light printing applications.

JP-A-11-194618 JP 2004-117957 A JP 2000-162817 A

  An object of the present invention is to provide an image forming method that solves the above-described problems, does not cause minute toner scattering for a long period of time, and is sufficiently satisfactory for demands of high definition and high image quality.

In the present invention, an electrostatic image carrier for carrying an electrostatic image is charged, an electrostatic image is formed on the charged electrostatic image carrier, and the electrostatic image is developed with toner on a developing sleeve. In an image forming method for forming a toner image,
The developing sleeve is subjected to Ni plating containing W at least on the outermost surface,
The toner contains at least 20.0% by mass to 60.0% by mass of a magnetic substance,
The present invention relates to an image forming method, wherein the amount of Mg contained in the magnetic material is 0.20 mass% or more and 3.00 mass% or less.

  According to the present invention, it is possible to obtain an image that is sufficiently free from minute toner scattering over a long period of time and that can sufficiently satisfy the demands of high definition and high image quality.

  The relationship between the toner layer formation state and toner scattering in the image forming process will be described with reference to the image forming process.

  In FIG. 1, the substantially right half surface of the developing sleeve 102 is always in contact with the toner reservoir in the toner container 106, and the toner near the surface of the developing sleeve is brought into contact with the magnetic force of the magnetic generating means 103 in the developing sleeve. And / or adhered and held by electrostatic force.

  When the developing sleeve 102 is driven to rotate, the toner layer on the surface of the developing sleeve is layered as a thin layer T1 having a uniform thickness in each part in the process of passing the position of the toner regulating member 104.

  In order to regulate the layer thickness, the toner layer thickness regulating member 104 is suspended from the surface of the developing sleeve 102 so as to face the developing sleeve 102 with a gap width of 100 μm or more and 300 μm or less. A magnetic layer from the magnetic pole N 1 of the magnetism generating means 103 concentrates on the regulating member 104, whereby a thin toner layer (toner layer) is formed on the developing sleeve 102.

  The toner layer T <b> 1 that has been layered is preferably thinner than the minimum gap between the developing sleeve 102 and the electrostatic image carrier 101 in the developing area A. Further, the frictional charging of the toner is mainly performed by the frictional contact between the surface of the developing sleeve accompanying the rotation of the developing sleeve 102 and the toner in the toner reservoir in the vicinity thereof.

  The surface of the toner thin layer on the developing sleeve 102 passes through the developing area A which is the closest portion between the electrostatic charge image carrier 101 and the developing sleeve 102 as the developing sleeve rotates.

  In this passing process, the toner of the toner thin layer on the surface side of the developing sleeve 102 flies by the direct current and the alternating current applied by the direct current and the alternating voltage between the electrostatic charge image carrier 101 and the developing sleeve 102. Then, it reciprocates between the surface of the electrostatic charge image carrier 101 in the developing area A and the surface of the developing sleeve 102 (gap α).

  Eventually, the toner on the developing sleeve 102 side is selectively transferred and attached to the surface of the electrostatic charge image carrier 101 according to the potential pattern of the latent image, so that toner images T2 are sequentially formed.

  The surface of the developing sleeve in which the toner is selectively consumed after passing through the developing area portion A is re-supplied to the toner reservoir of the toner container 106 to be re-supplied with toner, and the developing sleeve 102 is supplied to the developing area portion A. The surface of the toner thin layer T1 is transferred, and the development process is repeated.

  In this image forming process, the toner scattering level is greatly affected by the balance between the magnetic force and / or electrostatic force of the magnetic generating means 103 in the developing sleeve on the surface of the developing sleeve and the centrifugal force generated when the developing sleeve rotates. Effect. That is, the toner that cannot be sufficiently captured only by the adhesion force due to magnetic force and / or electrostatic force becomes the scattering toner.

  The present inventors have found that even when the balance between the adhesive force and the centrifugal force is optimized, there is a toner that scatters even though it is extremely small. In order to prevent this, in addition to the conventional magnetic attraction, electrostatic attraction (hereinafter referred to as interelement electrostatic attraction) that works between the metal element on the outermost surface of the developing sleeve and a specific element in the toner is controlled. Found that there is a need to do.

  Such a very small amount of scattered toner is hardly noticeable and does not cause a problem in a normal character image or the like, but it may be a problem for an image quality similar to a graphic image or a silver salt photograph.

  That is, the scattered toner becomes the fog toner, and the toner flies to the white portion of the image. As a result, there is a case where a graphic image that requires high definition and high image quality cannot be reproduced, and can be a defective image.

  As a result of intensive studies on the state in which the toner layer is formed on the developing sleeve, the present inventors have added tungsten (W) element to the outermost surface of the developing sleeve, and further added magnesium (Mg) to the magnetic material contained in the toner. It has been found that the above problems can be solved by adding a certain amount.

  It is known that W and Mg exhibit the opposite properties in the charged arrangement. W has a very high ability to attract electrons, while Mg has a property of easily releasing electrons. As a result, charge is transferred between the two elements, and an electrostatic attractive force between the elements acts between the toner and the developing sleeve. In particular, both have a large difference in electronegativity among metal elements, and charge transfer is very likely to occur.

  The electronegativity in the present invention is the value of Pauling's electronegativity (Source: AL Allred, J. Inorg. Nucl. Chem., 1961, 17, 215.).

  In addition to the conventional magnetic attractive force and adhesive force due to electrostatic force, it is possible to suppress a very small amount of toner scattering by the attractive force in the contact state between the outermost surface of the developing sleeve and the toner.

  Further, when Mg is contained in the magnetic material, the magnetic binding force and the above-described electrostatic attraction between elements can act simultaneously, and this effect is easily exhibited.

  Furthermore, when used for a long period of time, the toner may deteriorate due to embedding external additives, etc., and the charge balance may be lost, leading to toner scattering, but this interelement electrostatic attraction is less susceptible to toner deterioration. Even when used for a long time, the toner does not scatter.

  By the way, if the outermost surface is plated with W alone, durability is weak and this is not preferable. Therefore, it is preferable to perform plating with an element having a Vickers hardness Hv of 500 or more. Among these, the use of Ni is also a feature of the present invention. That is, Ni is located approximately in the middle between W and Mg in terms of electronegativity. Therefore, it is possible to improve only the wear resistance without hindering charge transfer between W and Mg.

  Next, the developing sleeve of the present invention will be specifically described.

  Specifically, the base material of the developing sleeve is preferably an aluminum alloy. These materials have low hardness, are relatively inexpensive, and have high thermal conductivity, so that distortion due to heat is small and image unevenness hardly occurs.

  Further, the developing sleeve of the present invention preferably has irregularities on the surface in order to improve toner conveyance and chargeability. The surface irregularities are preferably blasted with spherical particles (for example, glass beads). By processing with spherical particles, the surface of the developing sleeve after processing becomes smooth unevenness, and there is a tendency that toner clogging in the concave portion does not occur and the occurrence of contamination of the developing sleeve can be reduced.

  Next, an example of the developing sleeve plating layer of the present invention will be described with reference to FIG. 2 has an electroless plating intermediate layer 41b on a base layer 41a, and an Ni plating layer 41c containing W element directly bonded to the surface of the intermediate layer 41b on the outermost surface.

  Regarding the plating layer of the present invention, it is preferable to perform electroless plating on both the intermediate layer 41b and the surface layer 41c.

  In the case of electroplating, the uneven surface is preferentially attached to the convex portion where electrolysis concentrates, so that the plating layer becomes thick only in the convex portion, and a uniform plating layer can be formed. Can not. By using electroless plating, a plating layer can be formed uniformly and accurately regardless of the rough surface, and the amount of change in surface roughness before and after plating can be reduced.

  In the present invention, an electroless plating intermediate layer 41b is preferably provided between the base layer 41a and the electroplating surface layer 41c in order to cover cracks and protrusions on the surface of the base layer 41a.

  Further, the electroless plating intermediate layer 41b preferably has a Vickers hardness of Hv300 or higher from the viewpoint of wear resistance, and specifically, Ni-P, Ni-B, Cr, Pd-P, and the like. preferable. In particular, when used with a magnetic toner, nonmagnetic Ni—P or Ni—B is preferred.

  Also, the Ni plating layer 41c containing W is preferably plated by electroless plating for the above-described reason.

  The developing sleeve of the present invention preferably contains at least 0.5 wt% or more and 7.0 wt% or less in the plating layer on the outermost surface.

  By setting the W content in the above range, an appropriate inter-element electrostatic attraction acts and toner scattering can be prevented. In addition, the electrostatic attraction between elements becomes too large, and the toner tends to adhere to the developing sleeve in a high temperature and high humidity environment. By controlling the W content as described above, toner adhesion can be prevented. is there.

  In the developing sleeve of the present invention, B (boron) or P (phosphorus) is 0.5% by mass or more and 5.0% by mass or less, preferably 0.7% by mass or more and 3.0% by mass in the outermost plating layer. % Or less is preferable.

  B or P is almost 0 in the charged arrangement, and coexistence with W increases the stability of the electrostatic attraction between elements. Also, the plating strength is improved, which is preferable in terms of durability.

  The plating thickness is preferably 1 μm or more and 50 μm or less. By controlling the plating thickness, high wear resistance can be satisfied, and the surface irregularities of the developing sleeve can be easily inherited after plating.

  Moreover, it is preferable that the surface roughness after the plating treatment is in the range of 0.2 μm or more and 3.5 μm or less in terms of Ra.

  The magnetic material used in the present invention contains at least Mg in a range of 0.20 mass% to 3.00 mass%.

  The Mg content is 0.20% by mass or more and 3.00% by mass or less, preferably 0.25% by mass or more and 2.00% by mass or less, more preferably 0.30% by mass or more and 1.00% by mass or less. Preferably there is.

  If it is less than 0.20% by weight, the electrostatic attraction between elements becomes small, and toner scattering worsens. On the other hand, when the amount is more than 3.00% by mass, the electrostatic attractive force between elements becomes excessively large, and the toner easily adheres to the developing sleeve particularly in a high temperature and high humidity environment. As a result, the chargeability of the toner becomes non-uniform, which may lead to a decrease in developability.

  Further, the toner of the present invention preferably contains a magnetic material in an amount of 20.0 mass% to 60.0 mass%. More preferably, it is 30.0 mass% or more and 45.0 mass% or less.

  When the content of the magnetic material is less than 20.0% by mass, the transportability is insufficient and the toner layer on the developing sleeve is uneven, which may cause image unevenness. On the other hand, when the content of the magnetic material exceeds 60.0% by mass, the toner density of the developing sleeve increases, leading to a decrease in image quality, or a decrease in toner fluidity and chargeability. May decrease.

In addition, it is important that the relationship between the content of the magnetic material and the amount of Mg in the magnetic material satisfies the following relationship.
4.00 ≦ (magnetic substance content) × (Mg amount) ≦ 180.00

  This represents the amount of Mg present in the toner, and represents the charge transfer capability with the toner with W on the outermost surface of the developing sleeve. By satisfying the above relationship, it is possible to maintain an optimum inter-element electrostatic attraction between the toner and the developing sleeve.

  As a method for producing magnetic particles used in the present invention, a general method for producing magnetite particles can be used.

  Mg may be incorporated into the iron oxide crystal lattice, may be incorporated into the iron oxide as an oxide, or may be present on the surface as an oxide or hydroxide. Mg can be taken into the particles by mixing Mg salt at the time of magnetic substance production and adjusting the pH. Moreover, it can be made to deposit on the particle | grain surface by adjusting pH after magnetic body particle | grains production | generation, or adding Mg salt and adjusting pH.

  In the present invention, the magnetic body preferably has a polyhedral shape having 6 or more faces. A polyhedral magnetic body having a plurality of surfaces is preferable because it is superior in dispersibility in the binder resin and excellent in durability stability in the toner of the present invention as compared with a needle-like or spherical magnetic body.

Further, it is preferable that the magnetic material satisfies a BET specific surface area of 15.0 m ² / g or less, more preferably 13.0 m ² / g or less. When the BET specific surface area of the magnetic particles exceeds 15.0 m ² / g, the water adsorptivity of the magnetic particles increases, which affects the hygroscopicity and charging properties of the toner containing the magnetic particles.

  The number average particle diameter of the magnetic material is preferably 0.05 μm or more and 1.00 μm or less from the viewpoint of dispersibility of the magnetic material in the binder resin and toner charging uniformity, and is 0.08 μm or more and 0. More preferably, it is 30 μm or less. If the number average particle diameter of the magnetic material is larger than 1.00 μm, the number of magnetic particles contained in the toner is reduced, so that the dispersion of the magnetic material in the binder resin is likely to be biased, and the Uniformity may be impaired. When the number average particle size of the magnetic material is smaller than 0.05 μm, the adhesion between the magnetic particles is increased, and the dispersibility in the binder resin may be deteriorated.

  In the present invention, each physical property of the magnetic material is measured by the following method.

(1) Determination of Mg element present in magnetic substance 26 ml of hydrochloric acid aqueous solution in which 16 ml of special grade hydrochloric acid reagent is dissolved is added to 1.00 g of sample, and the sample is heated and dissolved, and then allowed to cool to room temperature. After adding 4 ml of a hydrofluoric acid aqueous solution in which 2 ml of a special grade hydrofluoric acid reagent is dissolved, the mixture is allowed to stand for 20 minutes. After adding 10 ml of Triton X (10% concentration), transfer to a 100 ml polymeas flask, add pure water, and adjust the total solution to 100 ml.

  The amount of Mg is quantified by using a plasma emission analyzer ICP S2000 manufactured by Shimadzu Corporation as a solution reagent.

(2) Particle size and shape of magnetic material Transmission electron microscope (TEM) H-700H, H-800, H-7500 (all manufactured by Hitachi, Ltd.) or scanning electron microscope (SEM) S-800 or S-4700 (Both manufactured by Hitachi, Ltd.) are used to photograph the magnetic material at a magnification of 20,000 to 100,000. At that time, the sample can be observed at an arbitrary magnification as a baking magnification of 1 to 5 times. For the particle size, 100 particles of 0.03 μm or more are selected at random, the maximum length (μm) of each particle is measured, and the average is taken as the number average particle size.

(3) BET specific surface area The BET specific surface area can be obtained from the BET specific surface area multipoint method by using a normal measuring device such as a specific surface area measuring device Gemini 2375 (Shimadzu Corporation) to adsorb nitrogen gas on the sample surface. it can. As sample pretreatment, deaeration is performed at 50 ° C. for 1 hour.

(4) Magnetic properties The magnetic properties (coercive force Hc, remanent magnetization σr, saturation magnetization σs) of the magnetic material were measured using an oscillating sample magnetometer VSM-3S-15 (manufactured by Toei Kogyo Co., Ltd.) and an external magnetic field of 7 .96 × 10 ² kA / m (10 kOe).

Saturation magnetization σs of the magnetic (Am ² / kg) is 60.0 or more 100.0Am ² / kg or less, preferably 70.0 or more 90.0Am ² / kg or less. Further, the residual magnetization σr is 1.0 to 30.0 Am ² / kg, more preferably 5.0 to 20.0 Am ² / kg, and the coercive force Hc is 1.0 to 30.0 kA / m, more preferably Is preferably 5.0 or more and 20.0 kA / m or less.

  As described above, by controlling both the amount of W on the developing sleeve and the amount of Mg in the toner magnetic material, it is possible to effectively extract the electrostatic attraction between elements, and there is no minute toner scattering over a long period of time. Therefore, it is possible to provide an image that can sufficiently satisfy the demand for high image quality.

  Examples of the binder resin used in the present invention include the following. Vinyl resin, styrene resin, styrene copolymer resin, polyester resin, polyol resin, polyvinyl chloride resin, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, Silicone resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin. Among them, a resin preferably used is a vinyl resin, a polyester resin, a hybrid resin in which a polyester resin and a vinyl resin are mixed, or both are partially reacted.

  The components of the polyester resin used in the present invention are as follows.

  The following are mentioned as a bivalent alcohol component. Ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol 2-ethyl-1,3-hexanediol, 1,4-cyclohexanedimethanol (CHDM), hydrogenated bisphenol A, bisphenol represented by formula (1) and derivatives thereof:

（式中、Ｒはエチレンまたはプロピレン基であり、ｘ、ｙはそれぞれ０以上の整数であり、かつ、ｘ＋ｙの平均値は０〜１０である。）、
および式（２）で示されるジオール類。

(Wherein R is an ethylene or propylene group, x and y are each an integer of 0 or more, and the average value of x + y is 0 to 10),
And diols represented by formula (2).

  Examples of the divalent acid component include the following dicarboxylic acids or derivatives thereof. Benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride or their anhydrides or lower alkyl esters thereof; alkyldicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid or their anhydrides or lower thereof Alkyl esters; alkenyl succinic acids or alkyl succinic acids such as n-dodecenyl succinic acid, n-dodecyl succinic acid, or anhydrides thereof or lower alkyl esters thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, itaconic acid Or its anhydride or its lower alkyl ester. In particular, terephthalic acid and isophthalic acid are preferable.

  Moreover, it is preferable that the said polyester resin contains the polyester resin containing the crosslinked structure by the polyhydric carboxylic acid more than trivalence or its anhydride, and / or the trihydric or more polyhydric alcohol.

  Examples of the trivalent or higher polyvalent carboxylic acid or anhydride thereof include 1,2,4-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and pyromellitic acid. And acid anhydrides or lower alkyl esters thereof.

  On the other hand, examples of the trihydric or higher polyhydric alcohol include 1,2,3-propanetriol, trimethylolpropane, hexanetriol, and pentaerythritol.

  Examples of the vinyl resin used for the binder resin include the following compounds.

  Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethyl Styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene Styrene derivatives such as: unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; Vinyl acetate such as vinyl acetate, vinyl propionate, vinyl benzoate Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, methacryl Α-methylene aliphatic monocarboxylic acid esters such as dimethylaminoethyl acid, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, Acrylic esters such as dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether Ter, vinyl ethers such as vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N- such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone. Vinyl compounds; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide.

  In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Alkenyl succinic acid half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester unsaturated dibasic acid half ester; dimethylmaleic acid, dimethyl fumaric acid unsaturated dibasic acid ester; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl resin used as the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. Examples of the crosslinking agent used in this case include divinylbenzene and divinylnaphthalene as aromatic divinyl compounds; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate and 1,3-butylene glycol diene. Examples include acrylate, 1,4-butanediol diacrylate, 1,5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and those obtained by replacing acrylate of the above compounds with methacrylate. The diacrylate compounds linked by an alkyl chain containing an ether bond include, for example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene Examples include lenglycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the above compounds in which acrylates are replaced by methacrylate; entangled with chains containing aromatic groups and ether linkages Examples of diacrylate compounds include polyoxyethylene (2) -2,2-bis (4hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4hydroxyphenyl) propane diacrylate, and Examples of the polyester type diacrylate compounds include “MANDA” manufactured by Nippon Kayaku Co., Ltd.

  Examples of the polyfunctional cross-linking agent include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and those obtained by replacing the acrylate of the above compounds with methacrylate; And lucyanurate and triallyl trimellitate.

  Among these cross-linking agents, those that are suitably used for binder resins from the viewpoint of fixability and offset resistance, are bonded with aromatic divinyl compounds (particularly divinylbenzene), chains containing aromatic groups and ether bonds. Diacrylate compounds are mentioned.

  The addition amount of these crosslinking agents is preferably 0.01 parts by mass or more and 10.00 parts by mass or less, and 0.03 parts by mass or more and 5.00 parts by mass with respect to 100 parts by mass of the vinyl monomer component. The following is more preferable.

  Examples of the polymerization initiator used for the polymerization of the vinyl polymer unit of the vinyl resin include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1 , 1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl -4-methoxyvaleronitrile, 2,2-azobis (2-methylpropane), methyl ethyl ketone peroxide, acetylacetone peroxide, Ketone peroxides such as rhohexanone peroxide, 2,2-bis (tert-butylperoxy) butane, tert-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroper Oxide, di-tert-butyl peroxide, tert-butyl cumyl peroxide, dicumyl peroxide, α, α'-bis (tert-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl peroxide Oxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethyl Xyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, dimethoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexyl Sulfonyl peroxide, tert-butyl peroxyacetate, tert-butyl peroxyisobutyrate, tert-butyl peroxyneodecanoate, tert-butyl peroxy 2-ethylhexanoate, tert-butyl peroxylaurate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, di-tert-butyl peroxyisophthalate, tert-butyl peroxyallyl carbe Sulfonates, tert- amyl peroxy 2-ethyl hexanoate, di -tert- Petit peroxy hexahydro terephthalate, di -tert- butyl peroxy azelate and the like.

  In the present invention, when the above-described hybrid resin is used as the binder resin, it is preferable that a monomer component capable of reacting with both resin components is contained in the vinyl resin and / or the polyester resin component. Examples of monomers that can react with the vinyl resin among the monomers constituting the polyester resin component include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Among the monomers constituting the vinyl resin component, those capable of reacting with the polyester resin component include those having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

  As a method of obtaining a reaction product of a vinyl resin and a polyester resin, a polymer containing a monomer component capable of reacting with a vinyl resin and a polyester resin exists, and a polymerization reaction of one or both resins is performed. The method obtained by making it preferable is preferable.

  In this hybrid resin, the mass ratio of the polyester monomer to the vinyl monomer is preferably from 50:50 to 90:10, and more preferably from 60:40 to 85:15.

  It is preferable that the binder resin has the following molecular weight distribution in the molecular weight distribution measured by gel permeation chromatography (GPC) soluble in tetrahydrofuran (THF).

  The peak molecular weight (Mp) is 5000 or more and 20000 or less, the weight average molecular weight (Mw) is 5000 or more and 300000 or less, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 5 or more and 50 or less. Preferably there is.

  When Mp and Mw are small and the distribution is sharp, high temperature offset tends to occur. Further, when Mp and Mw are large and the distribution is broad, the low-temperature fixability tends to be lowered.

  The glass transition temperature of the binder resin is preferably 53 ° C. or higher and 62 ° C. or lower from the viewpoint of fixability and storage stability.

  The binder resin may be used as a single product, but in the present invention, two kinds of high softening point resins having different softening points and a low softening point resin are mixed in a range of 90:10 to 10:90. You may do it. Such a system is preferable because the molecular weight distribution of the toner can be designed relatively easily and a wide fixing region can be provided.

  In the present invention, a wax can be used as necessary to give the toner releasability. As the wax, hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax are preferable because of easy dispersion in the toner and high releasability. If necessary, a small amount of one or two or more kinds of waxes may be used in combination. Examples include the following:

  Oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax, or block copolymers thereof; waxes based on fatty acid esters such as carnauba wax, sazol wax, and montanate wax; and deoxidation Deoxidized part or all of fatty acid esters such as carnauba wax. Furthermore, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassic acid, eleostearic acid, and valinalic acid; stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, and seryl alcohol Saturated alcohols such as melyl alcohol; long-chain alkyl alcohols; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; methylene bisstearic acid amide, ethylene biscaprin Saturated fatty acid bisamides such as acid amide, ethylene bislauric acid amide, hexamethylene bis stearic acid amide; ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N′-dioleyl Unsaturated fatty acid amides such as dipinamide, N, N-dioleyl sebacic acid amide; aromatic bisamides such as m-xylenebisstearic acid amide, N, N-distearylisophthalic acid amide; calcium stearate, laur Fatty acid metal salts such as calcium phosphate, zinc stearate, magnesium stearate (generally referred to as metal soap); waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid A partially esterified product of a fatty acid such as behenic acid monoglyceride and a polyhydric alcohol; a methyl ester compound having a hydroxyl group obtained by hydrogenation of a vegetable oil.

  Examples of the release agent particularly preferably used in the present invention include aliphatic hydrocarbon waxes. Examples of such aliphatic hydrocarbon waxes include the following. A low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or by using a Ziegler catalyst under low pressure. An alkylene polymer obtained by thermally decomposing a high molecular weight alkylene polymer. A synthetic hydrocarbon wax obtained from a distillation residue of hydrocarbons obtained from a synthesis gas containing carbon monoxide and hydrogen by the age method, and a synthetic hydrocarbon wax obtained by hydrogenating it. These aliphatic hydrocarbon waxes are fractionated by the use of a press sweating method, a solvent method, vacuum distillation or a fractional crystallization method.

  Examples of the hydrocarbon as the matrix of the aliphatic hydrocarbon wax include the following.

  Carbonization synthesized by the reaction of carbon monoxide and hydrogen using a metal oxide catalyst (often a multi-component system of two or more types) (for example, the Gintor method, Hydrocol method (using a fluidized catalyst bed)) Hydrogen compound). Hydrocarbons with up to several hundred carbon atoms obtained by the age method (using an identified catalyst bed) in which a large amount of waxy hydrocarbons can be obtained. Hydrocarbon obtained by polymerizing alkylene such as ethylene with Ziegler catalyst. Among such hydrocarbons, in the present invention, it is preferable that the hydrocarbon is a linear hydrocarbon having a small number of branches and a small length and a long saturation. In particular, hydrocarbons synthesized by a method not based on polymerization of alkylene are also preferred from the molecular weight distribution.

  For example, the following are mentioned. Biscol (registered trademark) 330-P, 550-P, 660-P, TS-200 (Sanyo Chemical Industries), high wax 400P, 200P, 100P, 410P, 420P, 320P, 220P, 210P, 110P (Mitsui Chemicals) ), Sazole H1, H2, C80, C105, C77 (Schumann Sazol), HNP-1, HNP-3, HNP-9, HNP-10, HNP-11, HNP-12 (Nippon Seiki Co., Ltd.), Unilin (registered trademark) 350, 425, 550, 700, Unicid (registered trademark), Unicid (registered trademark) 350, 425, 550, 700 (Toyo Petrolite), wood wax, beeswax, rice wax, candelilla wax Carnauba wax (available from Celerica NODA).

  The timing of adding the release agent may be added at the time of melt-kneading during toner production or may be at the time of binder resin production, and is appropriately selected from existing methods. These release agents may be used alone or in combination.

  The release agent is preferably added in an amount of 1 part by weight to 20 parts by weight with respect to 100 parts by weight of the binder resin. When the amount is less than 1 part by mass, it is difficult to obtain a desired release effect. When the amount exceeds 20 parts by mass, dispersion in the toner particles is poor, and toner adhesion to the electrostatic charge image carrier and surface contamination of the developing member / cleaning member are likely to occur, and the toner image tends to deteriorate.

  In the toner of the present invention, a charge control agent can be used to stabilize the chargeability. Although the charge control agent varies depending on the type and physical properties of other toner particle constituent materials, it is generally preferable that the toner particles are contained in an amount of 0.1 to 10 parts by mass per 100 parts by mass of the binder resin. More preferably, it is contained in an amount of 0.1 to 5 parts by mass. As such charge control agents, organometallic complexes and chelate compounds are effective. Examples thereof include monoazo metal complexes; acetylacetone metal complexes; metal complexes or metal salts of aromatic hydroxycarboxylic acids or aromatic dicarboxylic acids. In addition, examples of toners that are negatively charged include aromatic mono- and polycarboxylic acids and metal salts and anhydrides thereof; phenol derivatives such as esters and bisphenol.

  Specific examples that can be used include Spiron Black TRH, T-77, T-95 (Hodogaya Chemical Co., Ltd.), BONTRON (registered trademark) S-34, S-44, S-54, E-84, E- 88, E-89 (Orient Chemical). Moreover, charge control resin can also be used and can also be used together with the above-mentioned charge control agent.

In the toner of the present invention, a fluidity improver having a high fluidity-imparting ability to the toner particle surface and a BET specific surface area smaller than the number average particle diameter of primary particles is 50 to 300 m ² / g. Also good. As the fluidity improver, any fluidity improver can be used as long as the fluidity can be increased by adding the toner particles externally before and after the addition. For example, the following are mentioned. Fluorine-based resin powder such as fine vinylidene fluoride powder and polytetrafluoroethylene fine powder; fine powder silica such as wet-process silica, dry-process silica, and silica with silane coupling agent, titanium coupling agent, or silicone oil Treated silica with surface treatment. A preferred fluidity improver is a fine powder produced by vapor phase oxidation of a silicon halogen compound, and is referred to as dry process silica or fumed silica. For example, it utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.
SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl

  Further, in this production process, a composite fine powder of silica and another metal oxide obtained by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound may be used. The average primary particle size is preferably in the range of 0.001 to 2.000 μm, particularly preferably silica fine powder in the range of 0.002 to 0.200 μm. Good to do.

  Examples of commercially available silica fine powders produced by vapor phase oxidation of silicon halogen compounds include those sold under the following trade names.

  AEROSiL (Nippon Aerosil) 130, 200, 300, 380, TT600, MOX170, MOX80, COK84. Ca-O-SiL (CABOT Co.) M-5, MS-7, MS-75, HS-5, EH-5; Wacker HDK N 20 (WACKER-CHEMIE GNBH) V15, N20E, T30, T40; D-CFine Silica (Dow Corning Co.), Francol (Francil)

  Furthermore, it is preferable to use a treated silica fine powder obtained by hydrophobizing a silica fine powder produced by vapor phase oxidation of the silicon halogen compound. Among the treated silica fine powders, those obtained by treating the silica fine powder so that the degree of hydrophobicity titrated by a methanol titration test is in the range of 30 to 80 are particularly preferable.

  As a hydrophobizing method, it is applied by chemically treating with an organosilicon compound that reacts or physically adsorbs with silica fine powder. As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with an organosilicon compound. Examples of such organosilicon compounds include the following. Hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α- Chlorethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilyl mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, 1 -Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyl Ludisiloxane and dimethylpolysiloxane containing 2 to 12 siloxane units per molecule and containing hydroxyl groups bonded to one Si at each terminal unit. These are used alone or in a mixture of two or more.

  The inorganic fine powder may be treated with silicone oil, or may be treated in combination with the hydrophobic treatment.

As a preferable silicone oil, one having a viscosity of 30 to 1000 mm ² / s at 25 ° C. is used. For example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, and fluorine modified silicone oil are particularly preferred.

  Examples of the method for treating silicone oil include the following methods. A method in which silica fine powder treated with a silane coupling agent and silicone oil are directly mixed using a mixer such as a Henschel mixer. A method of spraying silicone oil onto silica fine powder as a base. Alternatively, after dissolving or dispersing silicone oil in an appropriate solvent, silica fine powder is added and mixed to remove the solvent.

  More preferably, the silicone oil-treated silica is heated to 200 ° C. or higher (more preferably 250 ° C. or higher) in an inert gas to stabilize the surface coating after the silicone oil treatment.

  A preferred silane coupling agent is hexamethyldisilazane (HMDS).

  In the present invention, the silica is preferably treated by a method in which silica is treated with a coupling agent and then treated with silicone oil, or a method in which silica is treated with a coupling agent and silicone oil at the same time.

  The fluidity improver is used in an amount of 0.01 parts by weight or more and 8.00 parts by weight, preferably 0.10 parts by weight or more and 4.00 parts by weight or less, based on 100 parts by weight of the toner particles. good.

  Other external additives may be added to the toner of the present invention as necessary. Examples thereof include resin fine particles and inorganic fine particles that function as a charging aid, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a release agent at the time of fixing with a heat roller, a lubricant, and an abrasive.

  Examples of the lubricant include polyethylene fluoride powder, zinc stearate powder, and polyvinylidene fluoride powder. Of these, polyvinylidene fluoride powder is preferred. Examples of the abrasive include cerium oxide powder, silicon carbide powder, and strontium titanate powder. These external additives can be sufficiently mixed using a mixer such as a Henschel mixer to obtain the toner of the present invention.

  In order to produce the toner of the present invention, the binder resin, the colorant, and other additives are sufficiently mixed by a mixer such as a Henschel mixer or a ball mill. Thereafter, the mixture is melt-kneaded using a heat kneader such as a heating roll, a kneader, or an extruder, cooled, solidified, and pulverized and classified. Further, if necessary, desired additives can be sufficiently mixed by a mixer such as a Henschel mixer to obtain the toner of the present invention.

  A method for measuring physical properties of the toner of the present invention is as follows. Examples described later are also based on this method.

(1) Measurement of molecular weight distribution by GPC A column is stabilized in a heat chamber at 40 ° C., THF is flowed through the column at this temperature as a solvent at a flow rate of 1 ml / min, and about 100 μl of a THF sample solution is injected and measured. . In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count value of a calibration curve prepared from several types of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, about 10 ² to 10 ⁷ are used, and at least about 10 standard polystyrene samples are suitably used. For example, TSK standard polystyrene manufactured by Tosoh Corporation (F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F -1, A-5000, A-2500, A-1000, A-500) can be used.

The detector is an RI (refractive index) detector. As a column, it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, combination or manufactured by Showa Denko KK of shodex GPC KF-801,802,803,804,805,806,807,800P, manufactured by Tosoh Corporation of _{TSKgel G1000H (H XL), G2000H} (H XL), G3000H (H XL ), G4000H (H _XL ), G5000H (H _XL ), G6000H (H _XL ), G7000H (H _XL ), and TSKgourd column.

  Moreover, a sample is produced as follows.

  1.0 g of toner and resin are placed in THF and allowed to stand at 25 ° C. for 24 hours. Then, a sample processing filter (pore size of about 0.5 μm, for example, Mysori Disc H-25-2 (manufactured by Tosoh Corporation)) can be used as a GPC sample.

(2) Measuring apparatus for measuring glass transition temperature of binder resin and toner: differential scanning calorimeter (DSC), MDSC-2920 (manufactured by TA Instruments)
Measured according to ASTM D3418-82.

  About 3 mg of the measurement sample is accurately weighed. This is put in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at normal temperature and humidity at a temperature increase rate of 10 ° C./min within a measurement temperature range of 30 to 200 ° C. The analysis is performed with a DSC curve in the temperature range of 30 ° C. to 200 ° C. obtained in the second temperature raising process.

  Although the basic configuration and features of the present invention have been described above, the present invention will be specifically described below based on examples. This does not limit the embodiment of the present invention.

<Example of manufacturing developing sleeve 1>
An aluminum base tube having an outer diameter of 32.0 mm and a wall thickness of 0.65 mm was used as a developing sleeve base, and the roller surface was roughened by performing a blasting process. As conditions, the abrasive grains were FGB # 600, blast pressure 2 kgf, rotational speed 10 rpm, blasting time 20 sec, blasting distance 150 mm, and blasting diameter Φ10. The surface roughness Ra of the obtained roller was 0.87 μm on an average of 6 points.

  Next, the roller surface after the blasting treatment is subjected to a zincate treatment, immersed in a Ni-P plating solution (S-754, manufactured by Nihon Kanisen Co., Ltd.), electroless plating is performed, and a 8.0 μm thick Ni—P plating is performed. A layer was formed.

  Subsequently, the roller subjected to the Ni—P plating treatment is immersed in a Ni—B—W plating solution (containing 5.0 mass% W and 1.0 mass% B) to perform electroless plating, A 1.0 μm-thick Ni—B—W plating layer was formed to form a developing sleeve 1.

<Example of production of developing sleeves 2 to 13>
In the manufacturing example of the developing sleeve 1, developing sleeves 2 to 13 were obtained in the same manner as in the manufacturing example of the developing sleeve 1 except that the outermost plating layer had the composition shown in Table 1.

(Magnetic substance production example 1)
An aqueous solution containing a ferrous salt containing magnesium as a main component is prepared so that the mass ratio (mass%) of Mg in the magnetic material is 0.50 mass%. A sodium hydroxide aqueous solution is mixed to obtain a ferrous hydroxide slurry.

  The pH of this ferrous hydroxide slurry is maintained at 12, and an oxidation reaction is performed at 80 ° C. The obtained slurry containing magnetite particles was subjected to dispersion treatment by applying mechanical shearing force, and then filtered, washed, dried and pulverized to obtain a magnetic body 1. Various physical properties are shown in Table 2.

(Magnetic substance production examples 2 to 5)
Magnetic bodies 2 to 5 were obtained in the same manner as in Production Example 1 except that the mass ratio (% by mass) of Mg was changed. Various physical properties are shown in Table 2.

(Magnetic substance production examples 6 to 9)
Magnetic bodies 6 to 9 were obtained in the same manner as in Production Example 1 except that the additive elements were changed as shown in Table 2. Various physical properties are shown in Table 2.

(Example of binder resin production)
Terephthalic acid 500g
600 g dodecenyl succinic acid
Trimellitic acid 350g
2000 g of bisphenol derivative represented by the formula (A)
(Propylene oxide 2.2 mol adduct)
800 g of bisphenol derivative represented by the formula (A)
(Ethylene oxide 2.2 mol adduct)
The acid component and alcohol component shown above and 4 g of dibutyltin oxide were charged into a four-necked flask, and equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device, and 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature.

  After completion of the reaction, the product was taken out from the container, cooled and pulverized to obtain a binder resin (H) having a softening point of 154 ° C.

next,
400g terephthalic acid
650 g of fumaric acid
2800 g of bisphenol derivative represented by the formula (1)
(Propylene oxide 2.2 mol adduct)
The acid component and alcohol component shown above and 4 g of dibutyltin oxide were charged into a four-necked flask and equipped with a decompression device, a water separation device, a nitrogen gas introduction device, a temperature measurement device, and a stirring device, and 230 ° C. in a nitrogen atmosphere. The reaction was carried out at an elevated temperature. After completion of the reaction, the product was taken out from the container, cooled and pulverized to obtain a binder resin (L) having a softening point of 93 ° C.

  Binder resin (H) 50 mass parts and binder resin (L) 50 mass parts were mixed with the Henschel mixer, and it was set as binder resin.

<Production Example of Toner 1>
Binder resin 51.0% by mass
Magnetic material 1 46.0% by mass
Fischer-Tropsch wax (melting point 105 ° C) 2.0% by mass
Charge control agent 1 (the following structural formula) 1.0 mass%

上記材料をヘンシェルミキサーで前混合した後、二軸混練押し出し機によって、溶融混練した。この時、混練された樹脂の温度が１５０℃になるように滞留時間をコントロールした。

The above materials were premixed with a Henschel mixer and then melt kneaded with a biaxial kneading extruder. At this time, the residence time was controlled so that the temperature of the kneaded resin was 150 ° C.

  The obtained kneaded product is cooled, coarsely pulverized with a hammer mill, then pulverized with a turbo mill, and the finely pulverized powder obtained is classified using a multi-division classifier utilizing the Coanda effect to obtain a weight average particle size of 7. Magnetic toner particles having a negative frictional charge of 0 μm were obtained.

To 100 parts by mass of magnetic toner particles, 1.0 part by mass of hydrophobic silica fine powder (BET140 m ² / g) and 3.0 parts by mass of strontium titanate (average particle size 1.2 μm) were externally mixed. Sieve with a mesh having an opening of 150 μm to obtain a magnetic toner 1 having negative tribocharging properties.

<Production Examples of Toners 2 to 9>
Toners 2 to 9 were obtained in the same manner as in the production example of Toner 1 except that the formulations shown in Table 3 were used.

[Example 1]
(1) Toner scattering evaluation: Monochrome copier IR-7105 (manufactured by Canon) under normal temperature and humidity (NN) (23 ° C / 50%) and high temperature and high humidity (HH) (30 ° C / 80%) The developing device was taken out and the developing sleeve was replaced with the developing sleeve 1. After that, toner was added and connected from an external motor to drive the developing unit. The peripheral speed of the developing sleeve was adjusted to 350 mm / s.

In this state, A4 paper was placed around the developing sleeve of the developing unit, and idle rotation was performed for 3 minutes and 1 hour. After completion of idling, any nine points on the paper were selected and magnified 150 times using a magnifying glass for observation. The toner scattering was evaluated based on the average number of toners per field of view.
A: Less than 5 B: 5 or more and less than 10 C: 10 or more and less than 15 D: 15 or more and less than 20 E: 20 or more

  The results are shown in Table 3.

(2) Evaluation of toner adhesion Under a high-temperature and high-humidity environment (HH) (30 ° C./80%), the developing device was taken out of the black and white copying machine IR-7105 (manufactured by Canon), and the developing sleeve was replaced with the developing sleeve 1. After that, toner was added and connected from an external motor to drive the developing unit. The peripheral speed of the developing sleeve was adjusted to 350 mm / s. In this state, idling was performed for 1 hour.

  After completion of idling, use a measuring container with cylindrical filter paper, attach a metal suction port along the shape of the developing sleeve surface, and adjust the suction pressure so that the toner layer on the developing sleeve surface can be sucked uniformly. Toner was sucked.

The suction part was taped off with a transparent adhesive tape, peeled off, and evaluated by a value obtained by subtracting the reflection density of the tape on which only the tape was applied from the reflection density on the paper. In addition, the measurement measured the arbitrary 5 points | pieces on a tape using the reflection-type densitometer (Tokyo Denshoku densitometer TC-6DS). The smaller the reflection density difference, the smaller the toner adhesion.
A: 0 or more and 0.2 or less B: 0.3 or more and 0.5 or less C: 0.6 or more and 0.8 or less D: 0.9 or more

  The results are shown in Table 3.

[Examples 2 to 11]
Evaluations were performed in the same manner as in Example 1 for the combinations of the developing sleeve and the toner shown in Table 3. The evaluation results are shown in Table 3.

[Comparative Examples 1 to 6]
Evaluations were performed in the same manner as in Example 1 for the combinations of the developing sleeve and the toner shown in Table 3. The evaluation results are shown in Table 3.

1 is a schematic diagram showing an example of an image forming apparatus suitable for forming an image using the magnetic toner of the present invention. It is a fragmentary sectional view showing an example of a development sleeve of the present invention.

Explanation of symbols

101: electrostatic charge image carrier 102: developing sleeve 103: magnetism generating means 104: toner regulating member 105: toner stirring member 106: developing container A: developing region T1: toner layer 41: developing sleeve 41a: base layer 41b: electric field Ni -P plating intermediate layer 41c: metal plating layer

Claims (5)

An electrostatic image carrier for carrying an electrostatic image is charged, an electrostatic image is formed on the charged electrostatic image carrier, and the electrostatic image is developed with toner on a developing sleeve to form a toner image. In the image forming method to
The developing sleeve is subjected to Ni plating containing W at least on the outermost surface,
The toner contains at least 20.0% by mass to 60.0% by mass of a magnetic substance,
An image forming method, wherein the amount of Mg contained in the magnetic material is 0.20 mass% or more and 3.00 mass% or less.   2. The image forming method according to claim 1, wherein the plating contains 0.5% by mass or more and 7.0% by mass or less of W in the plating layer.   3. The image forming method according to claim 1, wherein the plating contains 0.5% by mass or more and 5.0% by mass or less of P in the plating layer.   4. The image forming method according to claim 1, wherein the plating contains 0.5% by mass or more and 5.0% by mass or less B in the plating layer. An electrostatic image carrier for carrying an electrostatic image is charged, an electrostatic image is formed on the charged electrostatic image carrier, and the electrostatic image is developed with toner on a developing sleeve to form a toner image. In the toner used in the image forming method,
The developing sleeve is subjected to Ni plating containing W at least on the outermost surface,
The toner contains at least 20.0% by mass to 60.0% by mass of a magnetic substance,
A toner characterized in that the amount of Mg contained in the magnetic material is 0.20 mass% or more and 3.00 mass% or less.

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