JPH0556502B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an electrostatic image developing toner that constitutes a developer for developing electrostatic images formed in electrophotography, electrostatic recording, electrostatic printing, etc. It is. [Background of the Invention] For example, in electrophotography, an electrostatic latent image is usually formed by charging and exposing a latent image carrier made of a photoconductive photoreceptor, and then this electrostatic latent image is transferred to a latent image carrier made of a resin. A visible image is formed by developing with a fine particulate toner containing a colorant or the like in a binder, and transferring and fixing the resulting toner image onto a support such as transfer paper. In order to obtain a visible image as described above, it is necessary to fix the toner image, and conventionally, a heat roller fixing method that has high thermal efficiency and can perform high-speed fixing has been widely adopted. However, in recent years, there has been a strong demand for forming visible images at particularly high speeds, and from this point of view, it is necessary to perform the fixing process reliably and well in a wide temperature range while keeping the temperature of the heat roller lower. There is a strong demand for this, and there is a need for toners that fully satisfy these demands. This is because in high-speed image formation, the range of temperature change of the fixing heat roller is large. In addition, toner must be able to exist stably as a powder without agglomerating under the environmental conditions of use or storage, that is, it must have excellent blocking resistance. This is because offset phenomenon, in which part of the toner that makes up the image is transferred to the surface of the heat roller during fixing, is transferred again to the transfer paper that is sent next, and the image is smudged. It is necessary to provide performance that prevents the occurrence of offset phenomena, that is, non-offset property. This offset phenomenon occurs when the viscoelasticity of the melted toner during fixing is not appropriate, and when the toner is insufficiently heated or the adhesiveness of the toner is large, a phenomenon called under-offset occurs.
Furthermore, when the toner is heated excessively, a phenomenon called hot offset occurs. Therefore, as a toner, the minimum fixing temperature Tf at which it can be fixed is low;
In addition, it is preferable that the fixing temperature range is wide within the non-offset temperature range in which the offset phenomenon does not occur above the minimum fixing temperature Tf (temperature range above the under-offset occurrence temperature Tu and below the hot offset occurrence temperature Th). . [Problems to be Solved by the Invention] Methods for producing toner include a melt-kneading method, a suspension polymerization method, an emulsion polymerization method, and the like. The melt-kneading method involves melt-kneading a binder resin, a colorant, an anti-offset agent, or magnetic particles, etc., then pulverizing this, and further classifying it to obtain a powder with a desired particle size. In this method, a surface property modifier such as a particulate fluidity improver or an abrasive is added, and these are mixed and stirred to obtain a toner. In the suspension polymerization method and emulsion polymerization method, a powder with a desired particle size is obtained by suspension polymerization and emulsion polymerization, respectively, and a surface property modifier such as a fine particle flow improver or an abrasive is added to this powder. death,
This is a method of obtaining toner by mixing and stirring these. However, the toner obtained by such a method has a problem in that the performance of the surface property modifier is not necessarily fully exhibited. In other words, by adding the surface property modifier and mixing and stirring, the particulate surface property modifier adheres to the toner particle surface mainly by electrostatic force. When the toner is subjected to development, the surface of the surface property modifier gradually becomes coated with the binder resin of the toner.
As a result, the chargeability of the surface property modifier changes and the surface property modifier becomes liberated from the toner particles, or the performance of the surface property modifier is hindered, which ultimately reduces the durability of the toner. It gets lower. On the other hand, colored particles containing a thermoplastic resin are heated in a gas to soften the surface, and a surface property modifier such as a fine particle fluidity improver or abrasive is fixed to this to form a toner. A method for obtaining this has been proposed (see Japanese Patent Laid-Open No. 54-2741). According to this method, the surface property modifier can be fixed to the toner particles in a state where it is difficult to release, but in this method, the surface property modifier is completely embedded in the toner particles. There is a risk that the surface property modifier may become stuck, or a binder resin portion that protrudes larger than the surface property modifier may occur, which may impede the performance of the surface property modifier and ultimately result in insufficient durability. There are some problems that cannot be obtained. Such problems become particularly serious when a soft binder resin is used to improve low-temperature fixability. In addition, in the past, for example,
As disclosed in the above publication, a technique has been proposed in which a specific crystalline polymer having a melting point of 50 to 150° C. is used as a binder resin constituting a toner. However, in the conventional technology, although it is possible to set the minimum fixing temperature Tf to a low temperature,
Offset phenomenon tends to occur and the fixable temperature range is narrow, toner particles tend to aggregate with each other and blocking resistance is low, and toner substances adhere to the carrier particles and the surface of the photoreceptor, contaminating them. There are problems that can easily cause this phenomenon. In other words, when using a binder resin containing a crystalline polymer with a low melting point Tm, it is possible to fix at a lower temperature;
Since it contains a crystalline polymer with a low Tm, the crystalline polymer is present on the toner surface, and as a result, the cohesiveness of the toner increases due to the crystalline polymer with a high cohesive force, and therefore the toner substance Toner particles adhere to the carrier particles and the surface of the photoreceptor, causing a so-called filming phenomenon that inhibits their functions.In addition, toner particles aggregate together in the developing device when subjected to mechanical force or when the environmental temperature is high. This causes the problem of so-called blocking (clumping), which prevents the toner from functioning as a toner. Furthermore, when the toner is melted, its viscosity decreases due to the characteristics of the crystalline polymer, making it highly sticky.As a result, the adhesion of the molten toner to the heated roller increases, causing the problem of offset phenomenon. be. [Object of the Invention] The present invention has been made based on the above circumstances, and the first object of the present invention is to provide a system that has a low minimum fixing temperature Tf and a sufficiently wide fixable temperature range;
Therefore, it is an object of the present invention to provide a toner for electrostatic image development, which has a wide allowable temperature range of, for example, 50° C. or higher in a fixing roller, and can provide good fixing properties even in high-speed image formation. A second object of the present invention is to have sufficient fixing properties,
Moreover, it is an object of the present invention to provide a toner for electrostatic image development which has excellent anti-blocking properties and anti-filming properties and can stably form good visible images. A third object of the present invention is to provide a toner for electrostatic image development that has non-offset properties and has good fixing properties suitable for a hot roller fixing system. A fourth object of the present invention is to provide a toner for electrostatic image development in which various characteristics of fine powder added to the toner as an additive are fully exhibited. A fifth object of the present invention is to provide a color electrostatic image developing toner with excellent fixing properties. [Means for solving the problem] The electrostatic image developing toner of the present invention has a melting point Tm of 62
~135°C, crystalline polymer composed of 5 to 50% by weight of a crystalline polymer made of crystalline polyester having a weight average molecular weight of 3000 to 50000 and a number average molecular weight of 1000 to 20000 and 95 to 50% by weight of an amorphous polymer. Fine powder with an average particle size of 2 μm or less is attached to the surface of particles of a binder resin powder containing a binder resin, and then 48
The fine powder is driven into and held on the surface of the particles of the binder resin powder by applying a mechanical impact force while heating the crystalline polyester at a temperature higher than or equal to the melting point of the crystalline polyester. The present invention is characterized in that the surface layer of the particles of the binder resin powder in which the particles are present has a thickness of 2 μm or less. According to such a configuration, fine powder as a toner component is added to the surface layer of the binder resin powder containing a crystalline polymer having a melting point Tm of 62 to 135°C on the surface layer having a thickness of 2 μm or less. Since the fine powder is implanted and held, the fine powder is reliably present on the surface of the toner particles, and the characteristics of the fine powder suppress the development of agglomeration and stickiness caused by crystalline polymers, resulting in excellent toner particles. The toner has blocking resistance and filming resistance, and has good non-offset properties. Since such excellent performance is exhibited, it is possible to dramatically increase the content of crystalline polymer,
As a result, it is possible to obtain a toner that can achieve sufficient fixation at lower temperatures without impairing the above-mentioned excellent properties. The present invention will be specifically explained below. In the present invention, a powder of a binder resin composed of a crystalline polymer made of a specific crystalline polyester having a melting point Tm of 62 to 135°C and an amorphous polymer, or a powder of a binder resin to which other resins are added is used. Using a binder resin powder or a binder resin powder containing some toner components as necessary, fine powder as a toner component is applied on the surface of the binder resin powder particles. For example, it is electrostatically adhered by light stirring, etc., and then it is put into an impact type surface treatment device to apply mechanical impact force, and the very small amount of frictional heat and impact force generated at this time is used. The toner for electrostatic image development according to the present invention can be obtained by injecting and holding the fine powder on the surface of the particles of the binder resin powder. The details of the fine powder as a toner component that can be used in the present invention will be described later, but examples include black, white, or chromatic colorants, fluidity improvers, abrasives, charge control agents, and magnetic materials. There are fine particles, etc., and the average particle size thereof is preferably 2 μm or less, particularly 1 μm or less. These fine powders must be held in a surface layer of the binder resin powder particles with a thickness of 2 μm or less, preferably 1.5 μm or less, and at least some of the fine powder particles must be held on the surface layer. It is necessary to remain exposed from the layer. If the implantation is excessive and the fine powder penetrates to a depth of more than 2 μm from the surface of the particles of the binder resin powder, the characteristics of the fine powder will not be fully exhibited.
Blocking resistance and filming resistance deteriorate, and furthermore, the development of the characteristics of the crystalline polymer is inhibited by the fine powder, making it impossible to obtain sufficient low-temperature fixing properties. In the present invention, the state in which the fine powder as a toner component is "implanted and held" on the surface of the particles of the binder resin powder means, as shown in FIG. The ratio (D/L) of the length D of the part embedded in the surface layer of the binder resin powder particles 1 to the total length L in the direction perpendicular to the surface of the powder particles 1 is 5 to 95%. Describe the condition,
This can be easily confirmed by observing the surface of the toner particles using a transmission electron microscope or an electron microscope. In order to obtain such a state, in a system where binder resin powder and fine powder exist together, an impact force of a magnitude that does not crush the particles of binder resin powder, such as that normally required during crushing, is required. It is sufficient to apply an impact force of 1/5 to 1/10 of the force. Specifically, it varies depending on the properties of the binder resin, but per particle of binder resin powder, 1.59 × 10 ^-3 to 9.56 × 10 ^-5 erg,
Preferably, an impact force of 1.20×10 ⁻³ to 1.60×10 ⁻⁴ erg may be applied. Further, the time period for applying the impact force is selected based on the types of the binder resin and the fine powder, as well as the operating conditions of the impact type surface treatment device used. In the present invention, 50% of the total particles of the binder resin powder
% or more, it is preferable that the fine powder is in a state of being driven and held, and that 10 to 50% of the surface area of the binder resin powder is the state of being driven and held. Preferably, it is covered by. There are no particular restrictions on the specific treatment means for obtaining a state in which the fine powder is implanted and retained on the surface of the particles of the binder resin powder, and the treatment may be performed multiple times. Of course. The particles of the binder resin powder may be particles consisting only of the binder resin or particles in which some toner components are dispersed and contained in the binder resin. Examples of such toner components include colorants, charge control agents, magnetic particles, and other property improving agents. In the present invention, the average particle diameter of the toner particles is 1
It is preferable that it is -30 micrometers, and it is especially preferable that it is 5-20 micrometers. If the average particle diameter of the toner particles is too small, there is a risk that cleaning performance may be reduced or toner scattering may occur. On the other hand, when the average particle diameter of toner particles is too large, it becomes difficult to form an image with high resolution. Further, from the viewpoint of developability, it is preferable that the toner particles have a spherical shape, but they may have an amorphous shape. The crystalline polymer used in the present invention has a melting point Tm of 62 to 135°C, preferably 62 to 110°C. When a crystalline polymer with a melting point Tm that is too low is used, it becomes fluid at room temperature, resulting in a decrease in blocking resistance. On the other hand, when a crystalline polymer having an excessively high melting point Tm is used, sufficient low-temperature fixability cannot be obtained. In the present invention, the melting point Tm of a crystalline polymer is measured by heating a 10 mg sample of a crystalline polymer at a constant heating rate (10°C/
This refers to the melting peak temperature when heated at (min). Specific substances of such crystalline polymers include:
For example, polyesters containing polyalkylene polyesters in which the alkylene group has at least 2 carbon atoms (e.g., polydecamethylene sebacate, polydecamethylene succinate, polyethylene sebacate, polyethylene succinate, polyhexamethylene sebacate, polyhexamethylene sulfate) rate, polyhexamethylene succinate)
Crystalline polyesters such as The crystalline polymer constituting the binder resin has a weight average molecular weight Mw of 3,000 to 50,000 and a number average molecular weight Mn of 1,000 to 20,000. When using a crystalline polymer having a molecular weight too large or too small, pulverization tends to be difficult in the pulverizing step in the toner manufacturing process. In addition, weight average molecular weight Mw and number average molecular weight
The value of Mn can be determined by various methods, and since there are slight differences depending on the measurement method, in the present invention, it is determined by the following measurement method. That is, the weight average molecular weight Mw and number average molecular weight Mn are measured by gel permeation chromatography (GPC) under the conditions described below. At a temperature of 40℃, the solvent (tetrahydrofuran) was flowed at a flow rate of 1.2ml per minute, and the concentration was 0.2g/min.
Measurement is performed by injecting 20 ml of tetrahydrofuran sample solution to a sample weight of 3 mg. When measuring the molecular weight of a sample, the measurement conditions are such that the molecular weight of the sample falls within a range where the logarithm of the molecular weight and the count number of the calibration curve prepared using several types of monodispersed polystyrene standard samples are linear. Select. The reliability of the measurement results can be confirmed by confirming that the weight average molecular weight Mw = 28.8 x 10 ⁴ number average molecular weight Mn = 13.7 x 10 ⁴ for the NBS 706 polystyrene standard sample conducted under the above measurement conditions. . Moreover, any column may be used as the GPC column as long as it satisfies the above conditions. Specifically, for example, TSK-
GEL, GMH ₆ (manufactured by Toyo Soda Co., Ltd.), etc. can be used. In the present invention, the binder resin is a combination of the above crystalline polymer and amorphous polymer,
For example, it is composed of a blend, or a graft copolymer or block copolymer of these. By using a combination of a crystalline polymer and an amorphous polymer,
The amorphous polymer provides good non-offset properties, and as a result, the fixable temperature range can be widened. The polymerization blending ratio of the crystalline polymer and the amorphous polymer is crystalline polymer: amorphous polymer = 5 to
50:95-50. Such amorphous polymer has a glass transition point Tg
The temperature is preferably 35-80°C, particularly 40-70°C.
When an amorphous polymer with an excessively high glass transition point Tg is used, low-temperature fixing properties are reduced, while when an amorphous polymer with an excessively low glass transition point Tg is used, the viscoelasticity during melting is low and non-offset properties are reduced. There are cases where Here, the glass transition point Tg is
When measured using a differential scanning calorimeter "low temperature DSC" (manufactured by Rigaku Denki Co., Ltd.) at a heating rate of 10°C/min, the extension line and peak of the baseline below the glass transition point of the DSC thermogram in the glass transition region The temperature at the intersection with the tangent line showing the maximum slope between the rising part of the peak and the top of the peak. In addition, amorphous polymers have a softening point Tsp of 80 to 150.
The temperature is preferably 110 to 140°C. When an amorphous polymer with an excessively high softening point Tsp is used, low-temperature fixing properties are reduced, while when an amorphous polymer with an excessively low softening point Tsp is used, the viscoelasticity during melting is low and non-offset properties are reduced. There is. Here, the softening point Tsp is measured using a flow tester (CFT).
-500, manufactured by Shimadzu Corporation), the measurement conditions were as follows.
Load 200Kg/cm ² , nozzle diameter 1mm, nozzle length 1mm, preheating at 80℃ for 10 minutes, heating rate 6℃/
h is the height of the S-curve in the plunger drop-temperature curve (softening flow curve) of the flow tester when measuring and recording a sample amount of 1 cm ³ (weight expressed as intrinsic specific gravity x 1 cm ³ ). When,
It refers to the temperature at h/2. Such amorphous polymers include, for example, polymers or copolymers of monomers having vinyl groups,
Examples include polyester, epoxy resin, polyamide, polyurethane, and the like. Examples of monomers having a vinyl group include:
Styrene, o-methylstyrene, p-methylstyrene, p-ethylstyrene, α-methylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-n-octylstyrene, p-n
-dodecylstyrene, p-methoxystyrene, p
-Phenylstyrene, p-chlorostyrene, 3,
Styrenes and their derivatives such as 4-dichlorostyrene; Vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate; Vinyl chloride; Methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic Isobutyl acrylate, tert-butyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate , dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-methacrylate α-methylene aliphatic monocarboxylic acid esters such as ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; acrylonitrile,
Acrylic acid or methacrylic acid derivatives such as methacrylonitrile and acrylamide; Vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone; N
-vinylpyrrole, N-vinylcarbazole, N
- N-vinyl compounds such as vinyl indole and N-vinylpyrrolidone; vinylnaphthalenes; and others. Examples of polymers or copolymers of these monomers include styrene-n-butyl acrylate copolymer, styrene-n-butyl methacrylate copolymer, and styrene-n-butyl methacrylate copolymer.
Examples include rubbery copolymers such as methyl methacrylate copolymer, ethylene-vinyl chloride-vinyl acetate copolymer, and styrene-butadiene copolymer. Polyester as an amorphous polymer is obtained by condensation polymerization of a carboxylic acid component and an alcohol component, and the carboxylic acid component includes, for example,
Aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid naphthalenedicarboxylic acid; p-(2
Aromatic oxycarboxylic acids such as -hydroxyethoxy)benzoic acid; Aliphatic polycarboxylic acids such as succinic acid, fumaric acid, adipic acid, maleic acid, sebacic acid, decamethylene dicarboxylic acid; 1,4-cyclohexanedicarboxylic acid, 1 , 3-cyclohexanedicarboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid, and other alicyclic polycarboxylic acids; dicarboxylic acids are particularly preferred. Examples of the alcohol component include aliphatic polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, and neopentyl glycol. ; alicyclic polyols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; ethylene oxide or propylene oxide adducts of bisphenol A; and the like; glycols are particularly preferred. When a graft copolymer or block copolymer of a crystalline polymer and an amorphous polymer is used as a binder resin, the crystalline polymer and the amorphous polymer are directly bonded to each other in the molecules of the copolymer. or they may be bonded via an intermediate bond. This intermediate bond may consist of one single atom or may be a relatively low molecular weight group. Such intermediate bonds include, for example, -O-, -S-, -CO-, -COO-, or -CONH( _CH2 ) _o COO- (n is preferably an integer of 10 or less). etc. can be mentioned. The fine powder as a toner component held in the surface layer of the binder resin powder or the binder resin powder particles containing the desired toner component as described above includes a black, white, or chromatic coloring agent. , fluidity improvers, abrasives, charge control agents, and fine particles of magnetic materials. Examples of the coloring agent include carbon black, nigrosine dye (CI No. 50415B), aniline blue (CI No. 50405), and calco oil blue (C.
I.No.azoic Blue3), Chrome Yellow (CINo.
14090), Ultramarine Blue (CINo.77103),
DuPont Oil Red (CI No. 26105), Quinoline Yellow (CI No. 47005), Methylene Blue Chloride (CI No. 52015), Phthalocyanine Blue (C.
I.No.74160), malachite green oxalate (CINo.42000), lamp black (CINo.77266),
Rose Bengal (CI No. 45435), a mixture thereof, etc. can be used. In addition to these, the following pigments and dyes can be used as colorants. The exemplified substances below are CI listed in the color index.
An example of the name number and the corresponding product name is shown. Γ Red pigment CI Pigment Red 31 (Polymorose FBL, manufactured by Japan Chemical Industry Association) CI Pigment Red 84 (Patent Fastrubin RL, manufactured by Patent Chemicals) CI Pigment Red 89 (Fana Lux Pink RL, manufactured by GAF) CI Pigment Red 123 (Kaya Set Red E-B, Nippon Kayaku Co., Ltd.) CI Pigment Red 139 (Kaya Set Red E-GR, Nippon Kayaku Co., Ltd.) CI Pigment Red 144 (Chromophthal Red BRN, Ciba-Geigy Co., Ltd.) CI Pigment Red 149 (PV Fastret B, manufactured by Hoechst) CI Pigment Red 166 (Chromophthal Scarlet R, manufactured by Ciba Geigy) CI Pigment Red 177 (Chromophthal Red A3B, manufactured by Ciba Geigy) CI Pigment Red 178 (Kayaset Red E-GG, made by Nippon Kayaku Co., Ltd.) CI Pigment Red 190 (Fena Lux Scarlet VR, made by GAF Co., Ltd.) Γ Yellow pigment CI Pigment Yellow 6 (Sanyo Fast Yellow 3G, Sanyo Shiki Co., Ltd.) CI Pigment Yellow 12 (Benzidine Yellow, manufactured by EI Dupont) CI Pigment Yellow 13 (Fenarac Yellow BX, manufactured by GAF) CI Pigment Yellow 17 (Resol Yellow 1220, manufactured by BASF) CI Pigment Yellow 83 (Resol Yellow 1781K, manufactured by BASF) CI Pigment Yellow 95 (Chromophthal Yellow GR, manufactured by Ciba Geigy) Γ Green pigment CI Pigment Green 2 (Simiurex Green F, manufactured by Dainippon Ink and Chemicals) CI Pigment Green 7 (Chromophthal Tar Green GF, manufactured by Ciba Geigy) CI Pigment Green 36 (Fastogen Green 2YK, manufactured by Dainippon Ink and Chemicals) Γ Blue pigment CI Pigment Blue 2 (Juana Tone Blue B, manufactured by Sansui Shiki Co., Ltd.) CI Pigment Blue 3 (Juana Tone Blue 5B, Sansui Shiki Co., Ltd.) CI Pigment Blue 9 (Juana Tone Blue 6G, Sansui Shiki Co., Ltd.) CI Pigment Blue 14 (Haropont Blue RNM, EI Dupont Co., Ltd.) CI Pigment Blue 15 (Ruiga Light Blue BNS, CI Pigment Blue 16 (Luigazine Blue 3GT, manufactured by Ciba Geigy) CI Pigment Blue 60 (Sumica Coat Fast Blue BS, manufactured by Sumitomo Chemical) CI Pigment Blue 66 (Microsol Navy Blue BRS, manufactured by Ciba Geigy) Examples of the organic solvent-soluble dyes that can be preferably used include the following. Γ Red dye CI Solvent Red 3 (Orient Oil Brown BB, manufactured by Orient Chemical Co., Ltd.) CI Solvent Red 16 (Orient Oil Red BB, manufactured by Ciba Geigy) CI Solvent Red 24 (Orient Oil Red BB, manufactured by Orient Chemical Co., Ltd.) CI Solvent Red 83 (Eisenspiron Red BEH, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Red 125 (Orasol Red G, manufactured by Ciba Geigy) CI Solvent Red 179 (Kayaset Red A-2G, manufactured by Nippon Kayaku Co., Ltd.) Γ Orange dye CI Solvent Orange 2 (Eisen Edible Orange No. 2, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Orange 7 (Eisen Edible Red No. 5, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Orange 37 (Eisen Spiron Orange GRH, manufactured by Hodogaya Chemical Co., Ltd.) Γ Yellow Dye CI Solvent Yellow 2 (Orient Oil Yellow GG, manufactured by Orient Chemical Co., Ltd.) CI Solvent Yellow 14 (Orient Oil Orange PS, manufactured by Orient Chemical Co., Ltd.) CI Solvent Yellow 16 (Orient Oil Yellow 3G, manufactured by Orient Chemical Co., Ltd.) CI Solvent Yellow 25 (Eisenspiron Yellow 3RH, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Yellow 60 (Eisenspiron Yellow GRH, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Yellow 77 (Kayaset Yellow G, manufactured by Nippon Kayaku Co., Ltd.) Γ Green dye CI Solvent Green 3 (Kayaset Green A/B, manufactured by Nippon Kayaku Co., Ltd.) CI Solvent Green 20 (Sumiplast Green 5G, manufactured by Sumitomo Chemical Co., Ltd.) CI Solvent Green 29 (Kayaset Green 952, manufactured by Nippon Kayaku Co., Ltd.) Γ Blue dye CI Solvent Blue 4 (Eisen Victoria Blue B Base, manufactured by Hodogaya Chemical Co., Ltd.) CI Solvent Blue 49 (Orazol Blue BLN, manufactured by Ciba Geigy Co., Ltd.) CI Solvent Blue 83 (Kayaset Blue A-2R, manufactured by Nippon Kayaku Co., Ltd.) CI Solvent Blue 86 (Sumiplast Blue 3R, manufactured by Sumitomo Chemical Co., Ltd.) Γ Blue dye CI Solvent Violet 1 (Orazole Violet 3BN, manufactured by Ciba Geigy Co., Ltd.) CI Solvent Violet 21 (Eisenspiron Violet RH, manufactured by Hodogaya Chemical Co., Ltd.) One or more of the above pigments and dyes may be used depending on the color tone required for the toner. The ratio of the pigment to the dye used is such that the ratio Wd/Wp of the weight of the dye (Wd) to the weight of the pigment (Wp) is preferably in the range of 0.005 to 0.5. If this value is too small, the effect may not be obtained; on the other hand, if this value is too large, high concealability may not be obtained. The amount of colorant used is based on 100 parts by weight of toner.
The amount is 0.1 to 20 parts by weight, and 0.5 to 10 parts by weight is particularly preferable. If this amount is too small, the coloring density and hiding power may be insufficient, while if it is too large, the tone of the image will be dark and the toner may be damaged. Unfavorable effects may appear on charging properties or physical properties during heat fixing. It is necessary that the colorant fine particles be retained in the surface layer of the particles of the binder resin powder, and in particular the thickness
It is necessary that the surface layer is 2 μm or less. If the colorant fine particles are completely embedded in the particles of the binder resin powder due to excessive implantation, the blocking resistance, durability, and offset resistance will be poor. Further, it is preferable that the average particle diameter of the primary particles of the colorant fine particles is 2 μm or less. If this average particle size is too large, the fixing properties may be poor. The fluidity improver or abrasive is not particularly limited, and any known substance can be used. Specifically, nitrides such as boron nitride; carbides such as titanium carbide, tungsten carbide, zirconium carbide, boron carbide, and silicon carbide; silicon oxide, chromium oxide, cerium oxide, zirconium oxide, titanium oxide, magnesium oxide, and iron oxide. , oxides such as aluminum oxide, copper oxide, nickel oxide, zinc oxide; sulfates such as strontium sulfate, barium sulfate, calcium sulfate, aluminum sulfate, magnesium sulfate, copper sulfate; carbonates such as calcium carbonate, magnesium carbonate; calcium phosphate phosphates such as zirconium, lead, cobalt, nickel, magnesium, calcium, strontium, barium, aluminum, zinc, etc.; silicates such as sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, etc. Silicates; examples include emery, alundum, garnet, corundum, lime, trivoli, locksite, celite, bentonite, acid clay, and the like.
These substances may be used not only alone, but also in combination of two or more. Further, either a hydrophobized material or a non-hydrophobized material can be used. Fluidity improver fine particles or abrasive fine particles are
It is necessary that it is retained in the surface layer of the particles of the binder resin powder, and in particular, it is necessary that it be retained in the surface layer with a thickness of 2 μm or less. If the implantation is excessive and the fluidity improver fine particles or abrasive fine particles are completely embedded in the particles of the binder resin powder, sufficient fluidity or polishability cannot be obtained. Fluidity improver fine particles or abrasive fine particles are
It is preferable that the average particle diameter of the primary particles is 2 μm or less, particularly 1 μm or less. If this average particle size is too large, the properties of the binder resin, such as low-temperature fixability, may be inhibited. Further, the content of the fluidity improver fine particles or the abrasive fine particles is preferably 0.1 to 20% by weight, particularly 0.5 to 10% by weight, based on the entire toner.
If this content is excessive, the properties of the binder resin, such as low-temperature fixability, may be inhibited. The charge control agent is not particularly limited, and any known substance can be used. Examples of negatively chargeable materials include JP-A-57-141452 and JP-A-Sho.
58-7645, JP 58-111049, JP 58-185653, JP 57-167033,
Disclosed in Special Publication No. 44-6397 etc. 2:
Type 1 metal-containing azo dye; for example, JP-A-57-104940, JP-A-57-111541, JP-A-57-124357
Metal complexes of aromatic oxycarboxylic acids and aromatic dicarboxylic acids disclosed in Japanese Patent Application Laid-Open No. 53-127726; for example, copper phthalocyanine dyes disclosed in Japanese Patent Application Laid-open No. 52-45931. Examples include sulfonylamine derivatives or sulfonamide derivative dyes of copper phthalocyanine, sulfonamide and sulfonic acid or sulfonate derivative dyes of copper phthalocyanine, and the like. For example, as a positively chargeable one, JP-A-49-
Quaternary ammonium compounds disclosed in JP-A No. 51951, JP-A-52-10141, etc.; for example, JP-A-56-11461, JP-A-54-158932,
Alkylpyridinium compounds and alkylpicolinium compounds disclosed in U.S. Pat.
Examples include addition condensates disclosed in JP-A-80320. The charge control agent fine particles need to be held in the surface layer of the particles of the binder resin powder, and particularly need to be held in the surface layer with a thickness of 2 μm or less. When the charge control agent fine particles are completely embedded in the particles of the binder resin powder due to excessive implantation, sufficient charging performance cannot be obtained. Further, it is preferable that the average particle diameter of the primary particles of the charge control agent fine particles is 2 μm or less, particularly 1 μm or less. When charge control agent fine particles having an excessively large average particle diameter are used, the properties of the binder resin, such as low-temperature fixability, may be inhibited. In addition, the content of charge control agent fine particles is 0.1 to 20% by weight, especially 0.5 to 10% by weight based on the entire toner.
It is preferable that If the content of the charge control agent fine particles is excessive, the properties of the binder resin, such as low-temperature fixability, may be inhibited. The magnetic material is not particularly limited and any known material can be used. For example, in the case of obtaining a black toner, magnetite (triiron tetroxide), which is black in itself and also functions as a coloring agent, is used. can be particularly preferably used. Further, when obtaining a color toner, it is preferable to use a material with little darkness, such as metal iron. Typical magnetic or magnetizable materials include, for example:
Ferromagnetic metals such as cobalt, iron, nickel, aluminum, cobalt, iron, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, etc. Examples include metal alloys and mixtures thereof, and metal compounds containing metal oxides such as aluminum oxide, iron oxide, copper oxide, nickel oxide, zinc oxide, titanium oxide, and magnesium oxide. Some of these magnetic materials also function as a coloring agent, and in that case, they may also serve as a coloring agent. The magnetic fine particles must be held on the surface of the particles of the binder resin powder, and in particular, the magnetic particles must have a thickness of 2 μm.
It is necessary that the following surface layers are retained. When the magnetic fine particles are completely embedded in the particles of the binder resin powder due to excessive implantation, the expression of the properties of the binder resin is inhibited, and as a result, sufficient low-temperature fixing properties cannot be obtained. Further, sufficient blocking resistance or filming resistance may not be obtained in some cases. The average particle size of the primary particles of the magnetic fine particles is preferably 2 μm or less, particularly 1 μm or less. When using magnetic fine particles having an excessively large average particle diameter, the low-temperature fixing properties of the toner may deteriorate. In addition, when obtaining magnetic toner, the content ratio of magnetic fine particles is 20 to 65% of the total magnetic toner.
Preferably it is 25 to 45% by weight, especially 25 to 45% by weight. When the content of the magnetic fine particles is excessive, the low-temperature fixability may deteriorate. Further, in the present invention, other property improving agents may be injected into the particles of the binder resin powder to be retained therein, or may be dispersed and contained in the particles, if necessary. Such other property improving agents may, for example, have properties that prevent the occurrence of so-called toner filming phenomenon, in which toner substances adhere to the surface of carrier particles or the surface of a latent image carrier and impair these functions, or improve toner friction. It is used for the purpose of imparting various properties such as the property of improving charging properties. Specifically, for example, a resin that is an uncrosslinked polymer and does not contain chloroform-insoluble matter can be preferably used. The above colorants, charge control agents, magnetic substances, and other property improvers may be dispersed and contained in the particles of the binder resin powder instead of being implanted into the particles of the binder resin powder and retained. It may also be used. To give an example of a preferred method for manufacturing the toner for electrostatic image development of the present invention, first, the material resin of the binder resin or a toner component such as a colorant added thereto as necessary is melt-kneaded using, for example, an extruder. After cooling, it is finely pulverized using a jet mill or the like, and then classified to obtain a binder resin powder having a particle size desirable for use as a toner. Alternatively, a binder resin powder having a particle size desired as a toner can be obtained by melting and kneading the mixture using an extruder and spraying it in a molten state using a spray dryer or dispersing it in a liquid. Note that uniform compatibilization using an extruder requires only low-temperature heat and weak stirring, so the time required is short and there is no risk of cutting the molecular chains of the binder resin. Next, fine powder as a toner component is added to the obtained binder resin powder and stirred using, for example, a V-shaped mixer, thereby electrostatically applying the fine powder to the surface of the particles of the binder resin powder. After adhesion, this is then placed in, for example, an impact type surface treatment device as shown in FIG. 2 to apply an impact. In FIG. 2, 31 is a raw material hopper, 32 is a stirring motor, 33 is a supersonic nozzle, 34 is a collision plate, 35 is a recycling collector, 36 is a collection cyclone, 37 is a raw material inlet,
38 is compressed air, 39 is an exhaust outlet, and 40 is a binder resin powder particle and a fine powder particle. The treatment using the impact type surface treatment device is performed while heating to soften the material slightly. The heating temperature is 48° C. or higher and lower than the melting point Tm of the crystalline polymer of the binder resin. When this heating temperature exceeds the melting point Tm of the binder resin, the adhesiveness of the binder resin becomes high, and as a result, particles of the binder resin powder agglomerate together and form lumps in the impact type surface treatment device. may occur. On the other hand, if the heating temperature is too low, the binder resin becomes hard, which may require a long time to implant the fine powder and reduce production efficiency. In addition, it is preferable that the impact force applied to the binder resin powder and fine powder be as high as possible, but if it is too high, the binder resin powder may be further pulverized, so the impact force should be set to a level that does not cause such pulverization. It is preferable to do so. By performing the treatment in this manner, the fine powder can be implanted into the surface of the particles of the binder resin powder and retained therein. [Examples] Specific examples of the present invention will be described below, but the present invention is not limited thereto. <Example A1> (Production of binder resin powder) Γ Crystalline polymer 30 parts by weight Polyhexamethylene sebacate (melting point Tm = 62°C, weight average molecular weight Mw =
8800, number average molecular weight Mn = 2600) Γ Amorphous polymer 60 parts by weight Styrene-butyl acrylate-methyl methacrylate copolymer (weight composition ratio = 70:15:15, softening point Tsp =
126℃, glass transition point Tg = 60℃, weight average molecular weight Mw = 95000, number average molecular weight Mn = 9800) Γ Carbon black 10 parts by weight "Mogull L" (manufactured by Kyabot Co., Ltd.) Mix the above substances and roll two rolls. The mixture was melt-kneaded, cooled, and coarsely pulverized, then finely pulverized using a jet mill, and further classified to obtain a binder resin powder. This is referred to as "binder resin powder A11". (Production of toner) Γ Binder resin powder A11 94 parts by weight Γ Fine powder made of silicon oxide fine particles 6 parts by weight "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., particle size 16 mμ) After mixing the above substances, By applying impact force to these mixtures using the apparatus shown in Figure 2 at an ambient temperature of 52 to 55°C, silicon oxide fine particles are driven into the surface layer of the binder resin powder particles and held there. Thus, a toner according to the present invention was obtained. This is called "toner A1". This toner A1 had an average particle diameter of 12.2 μm, a thickness of the surface layer of the binder resin powder particles containing silicon oxide fine particles of 0.6 μm, and a softening point Tsp of 98°C. A two-component developer is prepared by mixing 5 parts by weight of Toner 1 and 95 parts by weight of a resin-coated carrier made by coating the surface of iron powder with a styrene-methyl methacrylate copolymer. A photocopying test was conducted using an electrophotographic copying machine "U-Bix 1600" (manufactured by Konishi Roku Photo Industry Co., Ltd.) to continuously form copied images 20,000 times. The presence or absence of filming was investigated. Further, toner A1 was left for one day under environmental conditions of a temperature of 50° C. and a relative humidity of 26%, and the blocking resistance was evaluated based on the presence or absence of aggregates. Furthermore, an unfixed image is formed using the above-mentioned electrophotographic copying machine using the above-mentioned developer, and a fixing test is performed on this unfixed image using a separately prepared fixing device by changing the set temperature of the fixing roller. The lowest set temperature at which the image does not peel off when rubbed with a wiper, that is, the lowest fixing temperature was determined. Further, an unfixed image is formed in the same manner as the above fixing test, and after this unfixed image is fixed by a fixing device, a blank sheet of paper is passed through the fixing device and whether or not the previously fixed image sticks to the blank sheet of paper. Find out if
The lowest temperature at which the image began to adhere, that is, the offset occurrence temperature was determined. These results are shown in Table 1 below. Table 1 also shows the difference between the offset occurrence temperature and the lowest fixing temperature, that is, the fixable temperature range. <Example A2> (Production of binder resin powder) Γ Crystalline polymer 50 parts by weight Polyethylene succinate (melting point Tm = 95°C, weight average molecular weight Mw =
6700, number average molecular weight Mn=2400) Γ Amorphous polymer 40 parts by weight Polypropylene isophthalate (softening point Tsp=119℃, glass transition point Tg=55
℃, weight average molecular weight Mw = 78000, number average molecular weight Mn = 4600) Γ Carbon black 10 parts by weight "Mogul L" (manufactured by Cabot) The above substances were treated in the same manner as in Example A1 to form a binder resin powder. Obtained. This is referred to as "binder resin powder A12." (Production of toner) Γ Binder resin powder A12 94 parts by weight Γ Fine powder made of silicon oxide fine particles 8 parts by weight "Aerosil OX50" (manufactured by Nippon Aerosil Co., Ltd., particle size 40 mμ) After mixing the above substances, Example A1 was prepared using the apparatus shown in the figure at an ambient temperature of 48-52°C.
A toner according to the present invention was obtained by processing in the same manner as above. This will be referred to as "toner A2". This toner A2 had an average particle size of 12.5 μm, a thickness of the surface layer of the binder resin powder particles containing silicon oxide fine particles of 0.9 μm, and a softening point Tsp of 102°C. A test similar to that of Example A1 was conducted using this toner A2. The results are also shown in Table 1. <Example A3> (Production of binder resin powder) Polyhexamethylene sebacate (melting point Tm = 62
℃, weight average molecular weight Mw = 8800, number average molecular weight
Mn=2600), polypropylene isophthalate (softening point Tsp=119℃, glass transition point Tg=55℃,
Weight average molecular weight Mw = 78000, number average molecular weight Mn =
4600) with toluylene diisocyanate at a weight composition ratio of 3:7 for block copolymerization to obtain a binder resin with a softening point Tsp of 107°C. Γ The above binder resin: 90 parts by weight Γ Carbon black: 10 parts by weight "Mogul L" (manufactured by Cabot Corporation) The above substances were treated in the same manner as in Example A1 to obtain a binder resin powder. This is referred to as "binder resin powder A13." (Production of toner) Γ Binder resin powder A13 96 parts by weight Γ Fine powder made of silicon oxide fine particles 4 parts by weight "Aerosil 200" (manufactured by Nippon Aerosil Co., Ltd., particle size 12 mμ) After mixing the above substances, Example A1 was prepared using the apparatus shown in the figure at an ambient temperature of 48-52°C.
A toner according to the present invention was obtained by processing in the same manner as above. This is called "Toner A3". This toner A3 had an average particle size of 11.9 μm, a thickness of the surface layer of the binder resin powder particles containing silicon oxide fine particles of 0.3 μm, and a softening point Tsp of 108°C. A test similar to that of Example A1 was conducted using this toner A3. The results are also shown in Table 1. <Comparative example a1> In Example A1, 94 parts by weight of binder resin powder A11 and silicon oxide fine particles "Aerosil R-972"
(manufactured by Nippon Aerosil Co., Ltd., particle size: 16 mμ) using a V-type mixer to obtain a comparative toner in which silicon oxide fine particles were adhered to the surface of the binder resin powder particles. This is referred to as "comparison toner a1". When this comparison toner a1 was observed under an electron microscope, it was found that the silicon oxide fine particles were not implanted into the surface layer of the particles of the binder resin powder but were only attached to the surface. Using this comparison toner a1, an actual photographic test similar to that of Example A1 was conducted. The results are also shown in Table 1. Comparative example a2 77 parts by weight of binder resin powder A11 in Example A1 and silicon oxide fine particles "Aerosil R-972"
(manufactured by Nippon Aerosil Co., Ltd., particle size 16 mμ) was mixed with 23 parts by weight using the apparatus shown in Fig. 2 in the same manner as in Example A1 except that the impact force was increased.
I also obtained a toner for comparison. This is referred to as "comparison toner a2". In this comparative toner a2, the thickness of the surface layer of the particles of the binder resin powder in which silicon oxide fine particles were present was 2.6 μm. Using this comparison toner a2, an actual photographic test similar to that of Example A1 was conducted. The results are also shown in Table 1. <Comparative example a3> (Production of binder resin powder) Γ Crystalline polymer 30 parts by weight Poly-1,4-cyclohexylene dimethylene pimelate (Melting point Tm = 42°C, weight average molecular weight Mw =
7200, number average molecular weight Mn = 2100) Γ Amorphous polymer 60 parts by weight Styrene-butyl acrylate-methyl methacrylate copolymer (weight composition ratio = 70:15:15, softening point Tsp =
126°C, glass transition point Tg = 60°C, weight average molecular weight Mw = 95000, number average molecular weight Mn = 9800) A binder resin powder was obtained by processing. Using this binder resin powder, a comparative toner was obtained in the same manner as in Example A1. "Compare this toner"
a3". This comparison toner a3 had an average particle diameter of 12.1 μm, a thickness of the surface layer of the binder resin powder particles containing fine silicon oxide particles of 1.2 μm, and a softening point Tsp of 92°C. Using this comparison toner a3, an actual photographic test similar to that of Example A1 was conducted. The results are also shown in Table 1. <Comparative example a4> (Production of binder resin powder) Γ Crystalline polymer 30 parts by weight Poly-ethylene-p-phenylene diacetate (melting point Tm = 137°C, weight average molecular weight Mw =
8400, number average molecular weight Mn = 2500) Γ Amorphous polymer 60 parts by weight Styrene-butyl acrylate-methyl methacrylate copolymer (weight composition ratio = 70:15:15, softening point Tsp =
126°C, glass transition point Tg = 60°C, weight average molecular weight Mw = 95000, number average molecular weight Mn = 9800) A binder resin powder was obtained by processing. Using this binder resin powder, a comparative toner was obtained in the same manner as in Example A1. Use this as a “comparison toner”
a4". This comparative toner a4 had an average particle size of 12.0 μm, a thickness of the surface layer of the binder resin powder particles containing fine silicon oxide particles of 0.1 μm, and a softening point Tsp of 132°C. Using this comparative toner a4, a photographic test similar to that of Example A1 was conducted. The results are also shown in Table 1. <Comparative example a5> (Production of binder resin powder) Γ Amorphous polymer of Example A1 90 parts by weight Styrene-butyl acrylate-methyl methacrylate copolymer Γ Carbon black 10 parts by weight "Mogul L" (manufactured by Kayabot Co., Ltd.) ) The above substance was treated in the same manner as in Example A1 to obtain a binder resin powder. Using this binder resin powder, a comparative toner was obtained in the same manner as in Example A1. Use this as a “comparison toner”
a5". The average particle size of this comparative toner a5 was 12.3 μm, and the thickness of the surface layer of the particles of the binder resin powder containing silicon oxide fine particles was 0.2 μm. Using this comparison toner a5, an actual photographic test similar to that of Example A1 was conducted. The results are also shown in Table 1.

〔Effect of the invention〕

As described above, according to the toner for electrostatic image development of the present invention, the toner is applied to the surface layer of the binder resin powder particles having a thickness of 2 μm or less containing a crystalline polymer having a melting point Tm of 45 to 135°C. Since the fine powder as a component is implanted and held, the fine powder is reliably present on the surface of the toner particles, and the characteristics of the fine powder prevent the development of agglomeration and stickiness caused by the crystalline polymer. As a result, the toner has excellent blocking resistance and filming resistance, and also has good non-offset properties. Since such excellent performance is exhibited, it is possible to dramatically increase the content of crystalline polymer, and as a result, sufficient fixing can be achieved at lower temperatures without sacrificing the above-mentioned excellent properties. You can get toner that you can. In addition, since the fine powder as a toner component is injected into the surface of the binder resin powder particles and held without kneading the binder resin, the resin used as the material of the binder resin does not deteriorate. Characteristics are imparted by the injected fine powder, and therefore the resin can be reliably used as a toner for developing electrostatic images without impairing its good characteristics. Furthermore, even when kneading is used to incorporate other toner components into the binder resin powder particles as necessary,
By retaining a part of the toner component on the surface of the particles of the binder resin powder by implantation, the amount of the toner component to be dispersed into the binder resin by kneading is reduced, so that it is easier to knead. The required conditions are significantly relaxed, and deterioration of the resin can be sufficiently prevented. Further, since the fine powder as a toner component held in the particles of the binder resin powder by implantation is present on the surface of the particles, its effect is sufficiently exerted. Therefore, it becomes possible to reduce the amount of the fine powder to be used. In addition, when fine particles of a fluidity improver such as silicon oxide fine particles are used as a fine powder and are injected into the particles of a binder resin powder to hold them, the fine particles of the fluidity improver are attached to the surface layer of the binder resin particles. Therefore, even when subjected to large mechanical forces such as by stirring, the fluidity improver fine particles do not separate from the binder resin particles and are stably maintained in the desired state, resulting in excellent properties. It has blocking resistance, high storage stability as a powder, and good developability in the development process.
As a result, clear images with high image density and no fogging can be stably formed many times. Since such excellent performance is exhibited, it is possible to use a resin that melts at a lower temperature as the resin constituting the particles of the binder resin powder, as long as it does not impede these performances. A toner with extremely excellent low-temperature fixability can be obtained. In addition, when a magnetic toner is constructed using magnetic fine particles as fine powder, the magnetic fine particles are implanted into and held in the surface layer of the binder resin particles, so that the magnetic fine particles are formed in the surface layer of the toner particles. Therefore, even when subjected to large mechanical forces such as agitation, the magnetic fine particles do not separate from the toner particles and are stably maintained in the desired state. Magnetic properties are stably obtained over a long period of time, resulting in a magnetic toner with extremely excellent durability. Since magnetic fine particles generally do not exhibit adhesiveness, their presence on the surface layer of the binder resin particles suppresses the development of cohesion and stickiness caused by the binder resin, resulting in It has excellent anti-blocking and anti-filming properties, has high storage stability as a powder, and can prevent contamination by binder resin substances on the surface of the latent image carrier or inside the developer container. As a result, good images can be stably formed many times. Since such excellent performance is exhibited, it is possible to use a resin that melts at a low temperature as the resin constituting the binder resin particles within a range that does not impede these performances, and as a result, low-temperature fixing properties are improved. It can be made into an extremely excellent toner. Since magnetic fine particles are generally hard, the presence of the magnetic fine particles on the surface layer of the binder resin particles increases the fluidity of the toner, which improves the developing performance and forms good images without image distortion. be able to. Furthermore, when charge control agent fine particles are used as fine powder and are injected into the particles of the binder resin powder to be retained, the charge control agent fine particles are firmly present in the surface layer of the binder resin particles. Therefore, even when subjected to a large mechanical force due to stirring or the like, the charge control agent fine particles do not separate from the binder resin particles and are stably maintained in the desired state, thus ensuring proper charging performance by the charge control agent fine particles. It is stably obtained over a long period of time and has extremely excellent durability. In the manufacturing process, there is no need to melt and knead the mixture of the binder resin and the charge control agent, so there is no risk of changes in the physical properties of the binder resin caused by the charge control agent and the charge control agent. . Therefore, even in toner, the physical properties of the binder resin, such as brittleness and softening point, can be fully utilized, and the crushability is not hindered in the crushing process, which is one of the toner manufacturing processes. , and finally it is possible to reliably obtain a toner having the target performance. Since the charge control agent fine particles are present in the surface layer of the binder resin particles,
The charge control agent effectively exhibits the chargeability, so that it is possible to obtain appropriate chargeability with a relatively small amount. Therefore, the amount of charge control agent used can be reduced, and manufacturing costs can be lowered. In addition, when fine abrasive particles are used as fine powder and are injected into the particles of the binder resin powder to hold them, the fine abrasive particles are firmly present in the surface layer of the binder resin particles. Even when the abrasive fine particles are subjected to large mechanical forces such as by stirring or stirring, the abrasive fine particles are stably held in the desired state without separating from the binder resin particles, and as a result, the abrasive fine particles are not scattered and the abrasive The abrasive properties of the fine particles can be stably obtained over a long period of time, and images can be formed without contamination, trouble, or filming caused by scattering of the abrasive particles. Since the abrasive fine particles are present in the surface layer of the binder resin particles, the polishing properties of the abrasive fine particles are effectively exhibited, and therefore it is possible to obtain good polishing properties with a relatively small amount.
Therefore, the amount of abrasive used can be reduced and manufacturing costs can be lowered. In addition, when color pigment fine particles are used as fine powder and are injected into particles of binder resin powder to be retained, it is necessary to melt and knead the mixture of binder resin and color pigment in the toner manufacturing process. Since it is unnecessary, there is no risk of causing a change in the physical properties of the color pigment and the binder resin due to the color pigment. Therefore, even in toner, the physical properties of the binder resin, such as brittleness and softening point, can be fully utilized, and the crushability is not inhibited in the crushing process, which is one of the toner manufacturing processes. Therefore, it is possible to reliably obtain a toner having the desired performance. Since the color pigment fine particles are present in the surface layer of the binder resin particles, the colors caused by the color pigments are reliably reflected, and a color image with a desired color can be reliably formed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the state of fine powder particles on the surface of binder resin powder particles, and FIG. 2 is an explanatory diagram showing an example of an impact type surface treatment apparatus. 1... Binder resin powder particles, 2... Fine powder particles,
31... Raw material hopper, 32... Stirring motor,
33... Ultrasonic nozzle, 34... Collision plate, 35...
... Recycling collector, 36 ... Collection cyclone, 37 ... Raw material inlet, 38 ... Compressed air inlet,
39...Exhaust outlet, 40...Binder resin powder particles and fine powder particles.

Claims (1)

[Claims] 1. Melting point Tm is 62 to 135°C, weight average molecular weight is
3,000 to 50,000, a crystalline polymer consisting of crystalline polyester with a number average molecular weight of 1,000 to 20,000.
Fine powder with an average particle diameter of 2 μm or less is attached to the surface of particles of a binder resin powder containing a binder resin composed of 95 to 50% by weight of an amorphous polymer, and then The fine powder is driven into and held on the surface of the particles of the binder resin powder by applying a mechanical impact force while heating to a temperature of 48° C. or higher and lower than the melting point of the crystalline polyester. A toner for electrostatic image development with improved characteristics, characterized in that a surface layer of particles of the binder resin powder in which fine powder is present has a thickness of 2 μm or less. 2. The toner for electrostatic image development with improved characteristics as set forth in claim 1, wherein the fine powder is a magnetic fine particle. 3. The toner for electrostatic image development with improved characteristics as set forth in claim 1, wherein the fine powder is charge control agent fine particles. 4. The toner for electrostatic image development with improved characteristics as set forth in claim 1, wherein the fine powder is abrasive fine particles. 5. The toner for electrostatic image development with improved characteristics as set forth in claim 1, wherein the fine powder is a color pigment fine particle. 6. The toner for electrostatic image development with improved characteristics as set forth in any one of claims 1 to 5, wherein the toner particles have an average particle size of 1 to 30 μm.