JP2000275912A - Toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the fixing temp. to a recording medium and to improve the transfer efficiency while suppressing the image fog by controlling resin toner particles to have the mol.wt. peak in a specified range and to have a specified circular degree. SOLUTION: The toner is prepared by externally adding fine particles (external additives) of a charge controlling agent, fluidity imparting agent or the like to color toner particles having the mol.wt. peak in 3000 to 60000 range and >=0.9 circular degree. If the mol.wt. peak of the resin toner particles is less than 3000, blocking of resin toner particles occurs due to increase in the low mol.wt. component and this makes normal production of resin toner particles impossible. If the peak exceeds 60000, the fixing temp. of an image increases due to the increase in the high mol.wt. component, which means an image can not be fixed at low temp. If the circular degree is less than 0.9, image fog generates or the transfer efficiency of the image to a recording medium decreases due to uneven distribution of resin toner particles in the image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner which can be suitably used in an image forming apparatus such as a copying machine, a printer, a plotter, a facsimile, etc., and more particularly to a resin having a molecular weight peak in the range of 3,000 to 60,000. The toner particles are used and the circularity of the resin toner particles is set to 0.9.
As described above, the present invention relates to a toner capable of lowering a fixing temperature on a recording medium and increasing transfer efficiency to a recording medium while suppressing image fogging.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, in order to form a thin layer of toner on an elastic developing roller, an elastic blade is pressed against the elastic developing roller with a certain pressing force or more. I have. As a result, the elastic developing roller and the elastic blade are distorted, the time during which the toner is in contact with the elastic blade is lengthened, and the toner is easily frictionally charged. Further, of the toner on the developing roller that has been frictionally charged by being pressed by the elastic blade, the toner that has not been developed is collected in the toner storage chamber via the supply roller. The collected toner is pressed against the developing roller again by the elastic blade and is triboelectrically charged.

[0003]

When such a pressing force is applied to the toner, fine particles externally added to the surface of the toner are driven into the toner particles, thereby deteriorating the function imparted during the production of the toner. Image quality deteriorates. For this reason, it is conceivable to form the toner with a tough material so that the externally added fine particles are not driven into the toner surface even if stress is applied, and the toner itself is not crushed or chipped. Further, it is conceivable to form the elastic blade with a rubber blade to reduce the pressing force on the toner. However, when a spherical toner is used, it may contain a large amount of high molecular weight components or a large number of cross-linking components so as to withstand the pressing force of the elastic blade. Therefore, there is a problem that the fixing temperature for fixing the toner on the recording medium increases. Further, when the elastic blade is formed by a rubber blade, the pressure contact force is reduced, so that there is a problem that poor charging of the toner occurs, causing image fog and a decrease in density.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and the molecular weight peak of the resin toner particles constituting the toner is reduced from 3000 to 6000.
By setting the circularity of the resin toner particles to 0.9 or more with the range of 0, even when a rubber blade having a weak pressing force is used, it is possible to lower the fixing temperature to the recording medium, It is another object of the present invention to provide a toner capable of increasing transfer efficiency to a recording medium while suppressing image fogging.

[0005]

According to a first aspect of the present invention, there is provided a toner according to a first aspect of the present invention, wherein at least fine particles containing a charge control agent are externally added to resin toner particles colored by a colorant. The resin toner particles have a molecular weight peak in the range of 3000 to 60000, and the circularity of the resin toner is 0.9 or more.

In the toner of the first aspect, based on the fact that the molecular weight peak of the resin toner particles is in the range of 3,000 to 60,000 and the circularity of the resin toner particles is 0.9 or more, a rubber blade having a weak pressing force is used. Even when the recording medium is used, it is possible to fix an image on a recording medium at a low fixing temperature, and it is possible to increase transfer efficiency to a recording medium while suppressing image fogging.

[0007] When the molecular weight peak of the resin toner particles is 3000 or less, the resin toner particles tend to block each other due to the increase in the low molecular weight component, and the resin toner particles become normal. Cannot be generated. When the molecular weight peak of the resin toner particles exceeds 60000, the fixing temperature of the image becomes high due to the increase of the high molecular weight component, and the image cannot be fixed at a low fixing temperature. Further, when the circularity of the resin toner particles is 0.9 or less, due to uneven filling of the resin toner particles with respect to the image, image fog occurs or the transfer efficiency of the image to the recording medium decreases. Would.

It is preferable that the resin toner particles are produced by dispersion polymerization of a monomer. When the resin toner particles are generated by the dispersion polymerization as described above, it is possible to generate the resin toner particles having a relatively uniform particle diameter by utilizing the characteristics of the dispersion polymerization. In addition, as a monomer used for dispersion polymerization, a vinyl monomer is preferable.

The charge control agent externally added to the resin toner particles preferably comprises a quaternary ammonium salt. Although various substances exist as charge control agents that can be used, quaternary ammonium salts have stable charging performance and can efficiently suppress the occurrence of image fog.

[0010] Further, as described in claim 4,
The average particle diameter of the resin toner particles is several μm, and the average particle diameter of the fine particles is desirably 1/10 or less of the resin toner particles. If the average particle diameter of the fine particles containing the charge control agent exceeds 1/10 of the resin toner particles, the durability printing performance is reduced or image fogging occurs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a toner according to the present invention will be described based on an embodiment embodying the present invention. Basically, the toner according to this embodiment is 3000 to 600
It has a molecular weight peak in the range of 00 and a circularity of 0.2.
It is obtained by externally adding fine particles (external additives) such as a charge control agent and a fluidity imparting agent to nine or more colored toner particles.

Here, the toner particles include dispersion polymerization,
Various particles such as polymerized particles prepared by methods such as suspension polymerization, emulsion polymerization, emulsion polymerization aggregation method, seed polymerization, pulverized particles manufactured by a pulverization method, and granulated particles manufactured by granulation can be used. is there. Among them, polymer particles polymerized by a dispersion polymerization method are particularly preferable for spherical toner. Such polymer particles have an average particle diameter of 1 to 20 μm.
And polymer particles having an average molecular weight in the range of 1,000 to 100,000 are desirable. Dispersion polymerization is a method in which a solvent is put into a polymerization reaction vessel, and materials such as a monomer, a dispersant, and an initiator are added and dissolved, and after the inside of the vessel is replaced with an inert gas, the liquid is stirred. After raising the temperature of the reaction system in the vessel while allowing the polymerization reaction to proceed for several hours to several tens of hours, the particle dispersion is separated into a solid content and a liquid content, and the solid content particles are collected to obtain polymerized particles. How to get.

Here, a specific method for producing toner particles by a dispersion polymerization method will be described. To produce toner particles by the dispersion polymerization method, a stirrer, a cooling pipe, a thermometer,
A solvent is filled in a reactor equipped with a gas inlet tube and the like, and the dispersant is dissolved. There, a monomer is mixed and an initiator is further dissolved. This is the so-called preparation.

As the solvent, methanol, ethanol,
Isopropyl alcohol, n-butanol, s-butanol, t-butanol, n-amyl alcohol, s-amyl alcohol, t-amyl alcohol, isoamyl alcohol, isobutyl alcohol, isopropyl alcohol, 2-ethylbutanol, 2-ethylhexanol, -Octanol, n-octanol, n-decanol, cyclohexanol, n-hexanol, 2-heptanol, 3-heptanol, 3-pentanol, methylcyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol , 3-methyl-1-butyn-3-ol, 4-methyl-2-pentanol, 3
Alcohols such as -methyl-1-pentyn-3-ol can be used alone or in combination of two or more. Further, as the organic solvent used in combination with these alcohols, for example, hexane, toluene, cyclohexane, benzene, hydrocarbon solvents such as xylene, ethyl benzyl ether, dibutyl ether, dipropyl ether, dibenzyl ether, Ethers such as dimethyl ether, tetrahydrofuran, vinyl methyl ether and vinyl ethyl ether, ketones such as acetaldehyde, acetone, acetophenone, diisobutyl ketone, diisopropyl ketone and cyclohexanone, ethyl formate, ethyl acetate, methyl acetate, ethyl stearate, methyl salicylate, etc. Esters and water. These solvents are used to adjust the SP (solubility parameter) value of the solvent system.

As dispersants, polystyrene, polyvinyl acetate, polymethyl methacrylate, polydimethyl siloxane, polyvinyl chloride, polyethylene, polypropylene, polylauryl methacrylate, polyoxyethylene, polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyacrylamide , Polyvinyl pyrrolidone, polyethylene imine, polyvinyl methyl ether,
Poly-4-vinylpyridine, polystyrenesulfonic acid and the like can be mentioned. These dispersants are used singly or as a mixture of several types.

As the monomer, a compound containing a vinyl group can be used. For example, styrene, methylstyrene, ethylstyrene, 2,4-dimethylstyrene,
Styrene monomers such as pn-butylstyrene and pt-butylstyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2 -Ethylhexyl methacrylate,
Stearyl methacrylate, methyl fatty acid monocarboxylic acid esters such as lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, vinyl ethers such as n-butyl vinyl ether, acrylonitrile, methacrylonitrile,
Vinyl compounds such as vinyl acetate, vinyl chloride, ethylene, propylene and chloroprene can be used alone or as a mixture of two or more. Among them, a copolymer of a styrene monomer and an acrylic monomer is most desirable.

The polymerization initiator is suitably added in an amount of 0.001 to 10% by weight, for example, lauryl peroxide,
An initiator such as benzoyl peroxide and azobisisobutyronitrile is used alone or as a mixture of a plurality of polymerization initiators.

Further, in order to enhance the thermal characteristics and strength of the toner particles, it is possible to mix and polymerize a crosslinking agent.
Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, divinyl ether, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate,
Examples thereof include triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol dimethacrylate, and polypropylene glycol dimethacrylate, which are used by being mixed with a polymerizable monomer. The solvent, dispersant, monomer, initiator, crosslinking agent and the like are not limited to these.

Here, in order to color the toner particles made of the above materials, a pigment dispersion or a dye is added during the polymerization to carry out the polymerization, or only the toner particles are first synthesized and then colored with the dye. There is. The most efficient method is to add a pigment or dye together with the polymerization, but it is necessary to select a colorant that does not inhibit the polymerization. And other additives, which affect the chargeability and environmental stability of the synthesized particles. When a colorant is added during polymerization, it is desirable to use a pigment dispersion. This pigment dispersion is obtained by mixing a solution in which a pigment is mixed with a dispersant and a solvent with hard particles of 1 to 10 mm made of glass beads, alumina, zirconia, etc., and using a sand grinder, attritor, paint shaker, ultrasonic dispersion With a disperser such as a disperser, a method of uniformly pulverizing the pigment and mixing and dispersing, or heating and kneading the pigment and the dispersant to uniformly disperse the pigment in the dispersant, and then dispersing the solvent using the disperser described above. It can be manufactured by a method of dispersing in.

The pigments usable in this pigment dispersion include CIPIGMENT BLACK 7, titanium black, CIPIGMENT
IGMENT BLUE 15,15: 1,15: 2,15: 3,15: 4,15: 5,15: 6,22,6
0,64, CIPIGMENT RED 9,97,122,123,149,168,177,18
0,192,215,216,217,220,223,224,226,227,228,240, C.
I.PIGMENT YELLOW 20,24,86,93,109,110,117,125,137,1
38, 147, 148, 153, 154, 166, 168, etc. can be used, but are not limited to these colors.

Solvents that can be used in the pigment dispersion include all solvents that can be used in the dispersion polymerization system and all polymerizable monomers, and are dispersed by the dispersibility of the pigment and the solubility of the dispersant in the solvent. It is necessary to use different solvents.

As the dispersant usable in this pigment dispersion, there are a surfactant, a resin-based dispersant and the like, and high dispersibility can be obtained by using these dispersants alone or in combination. Examples of the surfactant include anionic surfactants such as fatty acid salts, alkyl sulfate salts, alkyl aryl sulfonates, alkyl naphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, and alkyl diaryl ether disulfonates. ,
Alkyl phosphate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester salt and the like. As ionic surfactants, polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether,
Polyoxyethylene oxypropylene copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene fatty acid ester and the like, and as a cationic surfactant, an alkylamine salt, Examples thereof include quaternary ammonium salts, alkylpyridinium salts, and alkylimidazolium salts. Examples of the amphoteric surfactant include alkylbetaines and alkylamine oxides.

As the resin-based dispersant, a resin which is soluble in a solvent such as polyacryl, styrene-acryl copolymer, polyester, polyurethane and polyamide can be used. As the resin-based dispersant, a resin having a number average molecular weight of 1,000 or more is desirably used, and further, the glass transition temperature needs to be 50 ° C or more. If the glass transition temperature is 50 ° C. or less, blocking of particles is observed when the toner is formed.

In the case where only the toner particles are first synthesized and then colored with a dye, the toner particles are again dispersed in a solvent in which the dye is dissolved and colored. The solvent used for dyeing is a condition that does not dissolve the synthesized resin particles. Examples of this solvent include methanol, ethanol, isopropyl alcohol, n-butanol, s-butanol, t-butanol, n-amyl alcohol, s
-Amyl alcohol, t-amyl alcohol, isoamyl alcohol, isobutyl alcohol, isopropyl alcohol, 2-ethylbutanol, 2-ethylhexanol, 2-octanol, n-octanol, n-decanol, cyclohexanol, n-hexanol, 2-
Heptanol, 3-heptanol, 3-pentanol,
Methylcyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 3-methyl-1-butyn-3-ol, 4-methyl-2-pentanol, 3
Alcohols such as -methyl-1-pentyn-3-ol can be used alone or in combination of two or more. Incidentally, per 100 parts by weight of the organic solvent, the toner particles are:
It is desirable that 1 to 50 parts by weight and 1 to 30 parts by weight of the colorant are mixed.

The dyes include Disperse Red 4, 15, 53, 55, 59, 60, 91, 92, Disperse Blue 72, Disperse Violet 23,
30, 37, Solvent Violet 13, Disperse Yellow 31, 49, 61, 73, 82, 87, 8
8, 89, 90, 91, 93, 99, 109, 116,
118, 201, Solvent Yellow 32, 79, 93
Etc. can be used.

As a method for adding a charge control agent to the toner particles, a quaternary ammonium salt finely dispersed in a solvent is added to the toner particles as the polymerization proceeds, in the same manner as the above-described method for coloring the toner particles. There is a method of taking in the particles, and a method of driving the fine particles of the quaternary ammonium salt into the colored particles by using a device capable of giving a mechanical impact force to the toner surface, such as a hybridizer or mechanofusion. Either method can impart chargeability to the toner particles. However, when a quaternary ammonium salt is injected with a mechanical impact force, the toner particles are charged in an amount of 0.01 to 1 part by weight with respect to 100 parts by weight of the toner. The use of a small amount of a quaternary ammonium salt is sufficient to obtain the property. Examples of the charge control agent that gives a positive charge include a nigrosine dye, a quaternary ammonium salt, and triphenylmethane. Among these charge control agents, a quaternary ammonium salt has the most stable chargeability. And is a charge control agent that suppresses image fogging.

Further, it is desirable that a fluidity-imparting agent, an abrasive, a lubricant and the like having a particle diameter of 1/10 or less of the average particle diameter of the colored toner particles are mixed with the colored toner particles. As the fluidity imparting agent, silica, aluminum oxide, metal oxides such as titanium oxide by surface treatment,
Those subjected to a hydrophobic treatment are preferred. Examples of the polishing agent include oxides such as strontium titanate, cerium oxide, and aluminum oxide, and silicon compounds such as silicon nitride and silicon carbide. Further, as a lubricant, fatty acid metal salts such as zinc stearate and calcium stearate,
Fluorine compounds such as vinylidene fluoride and polytetrafluoroethylene are exemplified.

Next, in the production of toner particles by the dispersion polymerization method of the present embodiment, the above-mentioned solvent is charged into a reactor equipped with a stirrer, a cooling pipe, a thermometer, a gas introduction pipe, and the like. A dispersant or a coloring agent is appropriately mixed, and the inside of the reaction vessel containing the solution is replaced with nitrogen gas. Then, the polymerization initiator is dissolved, and the temperature of the dispersion is raised to 50 to 90 ° C. while stirring. To initiate polymerization.

Then, while confirming the particle size distribution and the conversion, the temperature is kept constant and the stirring is continued until the polymerization is completed for 5 to 24 hours. After the completion of the polymerization, the temperature of the polymer particle dispersion maintained at a constant temperature is lowered to room temperature to complete a series of polymerization operations. Subsequently, the toner particle dispersion solution is passed through a pressure filter to separate the toner particles and the solution, and is again dispersed in a solvent in order to wash away unreacted monomers and dispersants adhering to the toner particle surfaces. Further, the washing operation is repeated, and when it is recognized that the residue on the surface of the toner particles has been eliminated, the toner particles are dried.

As a result of measuring the particle size distribution of the polymer particles using a Multisizer II manufactured by Coulter Corporation, the volume average particle diameter was 3 to 10 μm. Therefore, the filter paper used after filtration after dyeing had a retention particle diameter of 3 μm. The polymer particles have a glass transition temperature of 50 to 80.
° C, the peak of the weight average molecular weight is 3000 to 60000
As a result, colored particles having a narrow particle size distribution in the range of 1.0 to 1.3 (volume average particle diameter / number average particle diameter) indicating the spread of the particle size distribution could be synthesized. In addition, the molecular weight was measured using HP company gel permeation chromatography. The value of volume average particle diameter / number average particle diameter was determined by using an average value obtained from a volume average distribution and a number average distribution measured using Coulter Multisizer II.

Next, the quaternary ammonium salt fine powder, which is a charge control agent, is added to the colored toner particles using a machine such as a hybridizer or mechanofusion with respect to 100 parts by weight of the colored toner particles. 0.01-1
The quaternary ammonium salt fine particles were externally added to the colored toner particles by driving in the range of parts by weight.

Further, a hydrophobic silica fine powder or the like as a fluidity-providing agent, an abrasive, a lubricant, or the like is added to the colored toner particles in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the colored toner particles. Using a mixer such as a mixer, the mixture was stirred and externally added to obtain a toner A.

The volume average particle diameter, dispersity (ratio of volume average particle diameter Dv / number average particle diameter Dp), molecular weight, and circularity of the toner A obtained as described above are measured using the Coulter Multisizer. II, measured by gel permeation chromatography from HP and flow particle image analyzer from SYSMEX. The degree of circularity is a value obtained by (circumferential length of a circle having the same projected area as the particle image) / (perimeter of the particle projected image). Further, this toner A was filled in a toner cartridge of a commercially available laser printer (Laser Printer HL-760 manufactured by Brother) to form an image on printing paper, and image fogging and durability printing performance were evaluated. After transferring to a recording medium with this laser printer (Laser Printer HL-760 manufactured by Brother), a fixing test was performed using an off-line fixing machine separate from development to measure the minimum fixing temperature. As will be described later, in each evaluation test, except for the evaluation test of Comparative Example 5, the laser printer (Brother Laser Printer HL-760) was used.
Replace the elastic blade attached to the developing device with a rubber blade (made of silicon rubber or urethane rubber)
A durable printing test was performed.

Next, Examples 1 to 5 and Comparative Examples 1 to 7 of the toner A obtained by the above manufacturing method will be described. First, a first embodiment will be described.

(Embodiment 1) Polymerization process (production of colored toner particles) 1 L equipped with a stirring blade, a cooler, a thermometer, and a gas inlet tube
Is mixed with 480 parts by weight of methanol and 120 parts by weight of isopropyl alcohol, and 20 parts by weight of polyvinylpyrrolidone is further dissolved. Styrene 1
60 parts by weight and n-butyl acrylate 40 parts by weight, 2,
6 parts by weight of 2-azobisisobutyronitrile was added and stirred. The contents of the flask were replaced with nitrogen gas while stirring, and 6
The temperature was raised to 0 ° C., and polymerization was started at a stirring blade rotation speed of 100 rpm. 90% polymerization conversion while keeping the temperature constant
, And the polymerization system temperature was returned to room temperature to complete the polymerization. This slurry was subjected to a first pressure filtration using a 3 μm filter, further redispersed in a mixed solvent of methanol and water, and then subjected to a second pressure filtration using a 3 μm filter, and dried overnight. I let it. 300
100 parts by weight of methanol is poured into a beaker of 10 ml, and 10 parts by weight of Kayalon polyester S-200 is added and dissolved in a water bath at 40 ° C. with stirring to disperse 30 parts by weight of the synthesized thermoplastic dry fine particles. While maintaining the temperature at 40 ° C., the mixture was stirred for 1 hour under heating reflux to effect dyeing. The first centrifugation was performed with a 3 μm filter, and further re-dispersed in 100 parts by weight of a 1: 1 solvent of methanol and water.
A second centrifugation was performed. The toner particles were dried all day and night to obtain black colored toner particles.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant, etc.) After 100 parts by weight of the colored toner particles, 1 part by weight of a quaternary ammonium salt is injected into the particle surface using a hybridizer, and then positively charged. 3 parts by weight of hydrophobic silica (average particle diameter: 30 nm) was mixed with a mixer and externally added to obtain a toner 1 for positively-chargeable dry development.

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 1 is 7.1 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp is:
1.04, the circularity is 0.96, and the molecular weight peak is 2
The resulting toner was a spherical toner having a weight of 6,500 (see FIG. 1). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. As a result, an image output maintaining the density was obtained (see FIG. 1). Further, after the transfer with this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 1).

(Embodiment 2) Polymerization process (production of colored toner particles) 1 L equipped with a stirring blade, a cooler, a thermometer, and a gas inlet tube
Is mixed with 480 parts by weight of methanol and 120 parts by weight of isopropyl alcohol, and 20 parts by weight of polyvinylpyrrolidone is further dissolved. Styrene 1
60 parts by weight and n-butyl acrylate 40 parts by weight, 2,
12 parts by weight of 2-azobisisobutyronitrile was added and stirred. Replace the inside of the flask with nitrogen gas while stirring,
The temperature was raised to 60 ° C., and polymerization was started at a stirring blade rotation speed of 100 rpm. The temperature was kept constant and the polymerization conversion was 90
%, The polymerization system temperature was returned to normal temperature, and the polymerization was completed. This slurry was subjected to a first pressure filtration using a 3 μm filter, further redispersed in a mixed solvent of methanol and water, and then subjected to a second pressure filtration using a 3 μm filter, and dried overnight. I let it. 30
Pour 100 parts by weight of methanol into a 0 ml beaker, add 10 parts by weight of Kayalon polyester S-200, dissolve in a water bath at 40 ° C. with stirring, and disperse 30 parts by weight of synthesized thermoplastic dry fine particles. While maintaining the temperature at 40 ° C., the mixture was stirred for 1 hour under heating reflux to effect dyeing. 3 μm
Was centrifuged for the first time, and further re-dispersed in 100 parts by weight of a 1: 1 solvent of methanol and water, followed by a second centrifugation. The particles were dried all day and night to obtain black colored toner particles.

2. External addition step (external addition of a charge control agent and a fluidity-imparting agent, etc.) After 100 parts by weight of the colored toner particles, 1 part by weight of a quaternary ammonium salt is injected into the particle surface using a hybridizer, and then positively charged. 3 parts by weight of hydrophobic silica (average particle diameter: 30 nm) was mixed with a mixer and externally added to obtain a toner 2 for positive charging dry development.

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 2 was 6.8 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp was:
1.07, the circularity is 0.93, and the molecular weight peak is 2
This resulted in a 2,000 spherical toner (see FIG. 1). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. As a result, an image output maintaining the density was obtained (see FIG. 1). Further, after the transfer by this laser printer, in a fixing test using an off-line fixing device different from the developing, fixing was possible at a minimum fixing temperature of 130 ° C. (see FIG. 1).

(Embodiment 3) 1. Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring are performed under exactly the same conditions as in Example 1 except that 0.5 part by weight of divinylbenzene is mixed to obtain black colored toner particles. Was completed.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 3 was obtained using the same method as in Example 1 for the charge control agent driving prescription and the external addition prescription. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 3 is 6.5 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp is:
1.05, the circularity is 0.93, and the molecular weight peak is 2
The toner became a spherical toner having a weight of 7000 (see FIG. 1). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. As a result, an image output maintaining the density was obtained (see FIG. 1). Further, after the transfer by this laser printer, in a fixing test using an off-line fixing device different from the developing, fixing was possible at a minimum fixing temperature of 150 ° C. (see FIG. 1).

(Embodiment 4) Polymerization Step (Production of Colored Toner Particles) Black and colored toner particles can be obtained by performing polymerization and coloring under exactly the same conditions as in Example 2 except that 1 part by weight of divinylbenzene was mixed. Was.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 4 was obtained using the same method as in Example 2 for the charge control agent driving formula and the external additive formula. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 4 was 6.9 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp was:
1.08, the circularity is 0.91, and the molecular weight peak is 2
It became a 3,000 spherical toner (see FIG. 1). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. As a result, an image output maintaining the density was obtained (see FIG. 1). Further, after the transfer with this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 1).

(Embodiment 5) Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring were carried out under exactly the same conditions as in Example 1 except that 4 parts by weight of 2,2-azobisisobutyronitrile was mixed to obtain a black toner. Colored toner particles were obtained.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 5 was obtained by using the same method as in Example 1 for the charge control agent driving formula and the external additive formula. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 5 was 7.1 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp was:
1.07, the circularity is 0.95, and the molecular weight peak is 3
It became a spherical toner having a weight of 8000 (see FIG. 1). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. As a result, an image output maintaining the density was obtained (see FIG. 1). Further, after the transfer by this laser printer, in a fixing test using an off-line fixing device different from the developing, fixing was possible at a minimum fixing temperature of 150 ° C. (see FIG. 1).

(Comparative Example 1) Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring were carried out under exactly the same conditions as in Example 1 except that 2 parts by weight of 2,2-azobisisobutyronitrile was mixed to obtain a black toner. Colored toner particles were obtained.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 6 was obtained by using the same method as in Example 1 for the injection prescription of the charge control agent and the external prescription of the external additive. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 6 was 6.8 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp was:
1.05, the circularity is 0.93, and the molecular weight peak is 6
It became a 5,000 spherical toner (see FIG. 2). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and this toner was filled in a durable printing test. Although an image output maintaining the density was obtained (see FIG. 2), the minimum fixing temperature was 190 in a fixing test using an off-line fixing machine different from development after transfer by this laser printer. The temperature was as high as ° C. (see FIG. 2). This is because the molecular weight peak of the toner particles is as high as 65,000, and the fixing temperature of the image becomes high due to the increase of the high molecular weight component, so that the image cannot be fixed at a low fixing temperature. It is thought that it was.

(Comparative Example 2) Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring were performed under exactly the same conditions with the same composition as in Example 1 to obtain black colored toner particles.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant, etc.) To 100 parts by weight of the colored toner particles, 1 part by weight of nigrosine as a charge control agent is injected into the particle surface with a hybridizer, and then the positive chargeability is adjusted. 3 parts by weight of hydrophobic silica (average particle diameter: 30 nm) was mixed with a mixer and externally added to obtain a positively chargeable toner 7 for dry development.

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 7 is 7.1 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp is:
1.04, the circularity is 0.96, and the molecular weight peak is 2
The resulting toner was a spherical toner having a weight of 6,500 (see FIG. 2). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and a toner printing test was performed by filling the toner with the elastic blade.
Image quality was reduced (see FIG. 2). This is presumably because nigrosine as a charge control agent was inferior in charging performance as compared with quaternary ammonium salts, so that durable printing performance was reduced and image fogging occurred. Further, after the transfer by this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 2).

(Comparative Example 3) Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring were performed under exactly the same conditions with the same composition as in Example 1 to obtain black colored toner particles.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant, etc.) After 100 parts by weight of the colored toner particles, 1 part by weight of a quaternary ammonium salt is injected into the particle surface using a hybridizer, and then positively charged. 3 parts by weight of hydrophobic titanium oxide (average particle diameter: 1 μm) were mixed by a mixer and externally added to obtain a positively chargeable toner 8 for dry development.

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 8 is 7.1 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp is:
1.05, the circularity is 0.95, and the molecular weight peak is 2
The resulting toner was a spherical toner having a weight of 6,500 (see FIG. 2). In addition, a laser printer (Brother Laser Printer H
L-760), an elastic blade attached to the developing device was modified to a rubber blade, and a durable printing test was conducted by filling the toner with the toner. (See FIG. 2). This is because the average particle diameter of the titanium oxide as an external additive is as large as 1 μm (1/10 or more of the volume average particle diameter of the toner particles of 7.8 μm), and the durability printing performance is reduced. It is considered that image fogging has occurred. Further, after the transfer by this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 2).

(Comparative Example 4) Polymerization Step (Production of Colored Toner Particles) The temperature was raised to 60 ° C. in the formulation of Example 1, and the polymerization was allowed to proceed under exactly the same conditions until the polymerization was started. 200 parts by weight of a one-to-one mixed solvent of methanol was added dropwise over 1 hour, and the polymerization was continued at a constant temperature until the polymerization conversion exceeded 90%.
The polymerization system temperature was returned to room temperature to complete the polymerization. This slurry was subjected to a first pressure filtration using a 3 μm filter, further redispersed in a mixed solvent of methanol and water, and then subjected to a second pressure filtration using a 3 μm filter, and dried overnight. I let it. Pour 100 parts by weight of methanol into a 300 ml beaker, and add Kayalon polyester S-2.
Then, 10 parts by weight of C.00 are added and dissolved in a water bath at 40 ° C. while stirring, and 30 parts by weight of the synthesized thermoplastic dry fine particles are dispersed. While maintaining the temperature at 40 ° C., the mixture was stirred for 1 hour under heating reflux for dyeing. The first centrifugation was performed with a 3 μm filter, and the mixture was redispersed in 100 parts by weight of a 1: 1 solvent of methanol and water, followed by a second centrifugation. The toner particles were dried all day and night to obtain black colored toner particles.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 9 was obtained by using the same method as in Example 1 for the injection prescription of the charge control agent and the external prescription of the external additive. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 9 was 7.2 μm, and the ratio (dispersion degree) of volume average particle diameter Dv / number average particle diameter Dp was:
1.12, the circularity is 0.84, and the molecular weight peak is 2
It became a 5,000 spherical toner (see FIG. 2). In addition, a laser printer (Brother Laser Printer H
L-760), a resilient blade attached to the developing device was modified into a rubber blade, and a toner printing test was performed by filling the toner. The printing was able to print up to 3000 sheets, but the transfer efficiency was poor ( (Transfer efficiency: 83%), and finally, ground fogging occurred and the image quality deteriorated (see FIG. 2). This is because the degree of circularity of the toner particles is as low as 0.84 and 0.9 or less, which causes uneven filling of the toner particles with respect to the image. As a result, image fog occurs and the recording medium It is considered that the transfer efficiency of the image to the recording medium was reduced. Also, after transferring with this laser printer,
In a fixing test using an off-line fixing device different from the development, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 2).

(Comparative Example 5) Polymerization Step (Production of Colored Toner Particles) Polymerization and coloring were performed under exactly the same conditions with the same composition as in Example 1 to obtain black colored toner particles.

2. External Addition Step (External Addition of Charge Control Agent and Fluidity Impartant) Toner 10 was obtained by using the same method as in Example 1 for the charge control agent driving prescription and the external addition prescription. .

3. Measurement and Evaluation of Toner The volume average particle diameter of the toner 10 is 7.1 μm, and the ratio of volume average particle diameter Dv / number average particle diameter Dp (degree of dispersion).
Was 1.04, the circularity was 0.96, the spherical toner had a molecular weight peak at 26500, and was almost the same shape as the toner 1 (see FIG. 2). In addition, the resilient blade attached to the developing device of the laser printer (Laser Printer HL-760 made by Brother) was not modified (with a metal blade attached), and the toner was filled with this toner. At the time of printing, the image was disturbed, the toner was fixed to the elastic blade, and a further printing test could not be performed (see FIG. 2). This is because the toner particles were pressed against the developing roller by the metal blade having a large pressing force, and the phenomenon of driving the external additive into the toner particles occurred, which led to a decrease in the durability printing performance. Conceivable. Further, after the transfer by this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 140 ° C. (see FIG. 2).

(Comparative Example 6) Toner production process by pulverization method 100 parts by weight of a styrene / butyl acrylate copolymer (peak molecular weight 22,000, glass transition point 72 ° C.)
7 parts by weight of carbon black and 2 parts by weight of a positively chargeable quaternary ammonium salt are mixed and melt-kneaded at 150 ° C. to form a colorant-dispersed mass. This lump was coarsely pulverized to particles having a particle diameter of 1 to 5 mm, and further to particles having an average particle diameter of 10 μm or less using a fine pulverizer utilizing a jet stream. Thereafter, classification was performed to obtain black colored toner particles. To 100 parts by weight of the colored toner particles, 2 parts by weight of positively chargeable hydrophobic silica (average particle diameter: 30 nm) was mixed by a mixer and externally added to obtain a positively chargeable toner 11 for dry development.

2. Measurement and Evaluation of Toner The volume average particle diameter of the toner 11 is 8.2 μm, and the ratio of volume average particle diameter Dv / number average particle diameter Dp (degree of dispersion).
Was 1.28, the circularity was 0.86, and the spherical toner had a molecular weight peak of 22,000 (see FIG. 2). In addition, a resilient blade attached to a developing device of a laser printer (Brother Laser Printer HL-760) was modified into a rubber blade, and a durable printing test was performed by filling the toner with the toner.
It was possible to perform printing without disturbing the image and obtain an image output maintaining the density. However, the transfer efficiency was 85% and did not exceed 90% (FIG. 2).
reference). This is because the circularity of the toner particles is as low as 0.86 and not more than 0.9, causing unevenness in the filling of the toner particles to the image. As a result, image fogging occurs and the recording medium It is considered that the transfer efficiency of the image to the recording medium was reduced. Further, after the transfer with this laser printer, in a fixing test using an off-line fixing machine different from the developing, fixing was possible at a minimum fixing temperature of 150 ° C. (see FIG. 2).

(Comparative Example 7) Polymerization Step (Production of Colored Toner Particles) Except that the synthesis was carried out in the same manner as in Example 1, and the styrene was changed to 140 parts by weight, n-butyl acrylate 60 parts by weight, and 2,2-azobisisobutyronitrile 24 parts by weight. Is
Polymerization was performed under the same composition and under the same conditions as in Example 1 to obtain a toner 12 slurry. Then, this slurry is 3 μm
When the first pressure filtration was performed using the filter of
The particles blocked each other on this filter and tried to disperse in a mixed solvent of methanol and water. However, sufficient dispersion could not be performed, and washing could not be continued. The peak of the molecular weight of the toner 12 was 2800 (FIG. 2).
reference). This means that the molecular weight peak of the toner particles is 2800.
And 3000 or less, the resin toner particles tend to block each other due to the large amount of the low molecular weight component, making it impossible to generate the resin toner particles normally. It is thought that it was.

[0068]

As described above, in the toner of the first aspect, the molecular weight peak of the resin toner particles is 3,000 to 600.
00 and the circularity of the resin toner particles is set to 0.
Based on the setting of 9 or more, even when a rubber blade having a weak pressing force is used, it is possible to fix an image on a recording medium at a low fixing temperature and to suppress image fogging. Transfer efficiency to a recording medium can be increased. At this time, as described in claim 2, when the resin toner particles are generated by performing the dispersion polymerization of the monomer, the resin having a relatively uniform particle diameter by utilizing the characteristics of the dispersion polymerization. It is possible to produce toner particles. Further, when a quaternary ammonium salt is used as the charge control agent, the charging performance of the resin toner particles is stabilized, and the occurrence of image fogging is efficiently suppressed. Is possible. Further, as described in claim 4, when the average particle diameter of the resin toner particles is several μm and the average particle diameter of the fine particles is 1/10 or less of the resin toner particles, the durability printing is performed. It is possible to suppress image fogging while maintaining high performance.

[Brief description of the drawings]

FIG. 1 shows the amount of a polymerization initiator, the amount of a crosslinking agent, and the amounts of Examples 1 (toner 1) to 5 (toner 5) according to the present embodiment.
Charge control agent, flowability imparting agent amount, volume average particle diameter of toner, circularity, dispersity, molecular weight peak, durable printing number,
4 is a table showing a comparison between a minimum fixing temperature, presence or absence of image fog, external additive particle diameter, and transfer efficiency.

FIG. 2 shows the amounts of a polymerization initiator, a cross-linking agent, a charge control agent, a fluidity-imparting agent, and a volume average particle diameter of a toner for Comparative Examples 1 (toner 6) to 7 (toner 12) according to the present embodiment. 3 is a table showing a comparison of the degree of circularity, degree of dispersion, peak of molecular weight, number of durable printed sheets, minimum fixing temperature, presence or absence of image fog, external additive particle diameter, and transfer efficiency.

Claims (4)

[Claims] 1. A toner in which fine particles containing at least a charge control agent are externally added to resin toner particles colored with a colorant, wherein the resin toner particles have a molecular weight peak in the range of 3,000 to 60,000, A toner having a circularity of 0.9 or more. 2. The toner according to claim 1, wherein the resin toner particles are generated by performing dispersion polymerization of a monomer. 3. The toner according to claim 1, wherein the charge control agent comprises a quaternary ammonium salt. 4. An average particle diameter of the resin toner particles is several μm.
4. The toner according to claim 1, wherein the average particle diameter of the fine particles is 1/10 or less of the resin toner particles. 5.