JPH0468360A - Toner - Google Patents

Abstract

PURPOSE:To obtain a toner with an improved fixing property and with hardly generating the offset, as well by incorporating a specified fixing resin and a coloring agent, and making at least >=1 region where the gradient of viscosity (absolute value) of the toner in a specified temp. region is less than 0.030/ deg.C exist. CONSTITUTION:The toner incorporates the fixing resin and the coloring agent, and the fixing resin satisfies the range of 50,000-5,000,000 in the weight average molecular weight and the region where the gradient of the toner viscosity (absolute value) in a range of 100-150 deg.C is <=0.30/ deg.C, is present at least >=1. In this case, the toner particle melts adequately at the fixation and it can maintain the permeability and the flocculation property suitable to the fixation. Thus the improved toner excellent in the compatibility to a fixing roller, etc., and without easily peeling off from transfer paper and with the resistance to the offset property is obtained.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a toner used in electrophotography, and more particularly to a toner that is highly compatible with a fixing roller of an image forming apparatus. Regarding.

(Prior Art) Toners used in the field of electrophotography are formed of particles consisting of a fixing resin, a colorant, and, if necessary, a charge control agent, a magnetic material, and a release agent.

The toner is usually electrically attracted to the electrostatic latent image portion on the surface of the photoreceptor and developed, and then transferred to a transfer material (paper) and conveyed to a fixing mechanism. The resin that fixes the toner on the transfer paper is melted by the thermal action of a fixing roller, etc., and the toner is fixed on the transfer paper, completing fixing.

When toner is normally fixed, it is required to have fixability to transfer paper and anti-offset properties. Good fixing of the toner is achieved when the fixing resin is melted to some extent by a fixing roller or the like and sufficiently adhered to the transfer paper. Furthermore, offset of the fixing roller occurs when the resin is not sufficiently melted by the fixing roller and the resin hardens and sticks to the roller, or when the fixing resin loses its near-liquid viscosity and wets the roller. Therefore, offset resistance of the toner is achieved when the fixing resin has appropriate permeability and cohesiveness, and cold offset and hot offset do not occur.

(Problems to be Solved by the Invention) Conventionally, in order to improve the fixing properties and anti-offset properties of a toner, there is a fixing resin containing a low molecular weight hydrogenated polybutadiene (Jikai +1H80-103354). The purpose of this is to improve the fixing performance by quickly melting the low molecular weight fixing resin component by the fixing roller. In addition, a reactive prepolymer may be contained (Japanese Patent Application Laid-Open No. 110948/1983), or the ratio of styrene and 2-ethylmethahexyl methacrylate as a binder resin may be used within a certain range (Japanese Patent Application Laid-Open No. 1988-110948). 60-57855), one having anti-offset properties has already been proposed.

However, in conventional toners, a low molecular weight fixing resin is simply added (or present) to the particles, and there is still room for improvement.

For example, if the heating conditions of the fixing roller change slightly during fixing, the fixing resin in the toner changes its permeability and cohesiveness, which may reduce its fixing properties and anti-offset properties. During fixing, the fixing roller is kept at a certain constant temperature, heating the toner particles and melting them appropriately, but the fixing roller surface is heated from the time the toner starts fixing to the end of fixing a large amount of toner, especially during fixing. It is unavoidable that the temperature changes slightly between the start and end of fixing, and it is difficult for the toner to always be heated at a constant temperature and for a constant time from the fixing roller.

Therefore, one object of the present invention is to take these circumstances into consideration.

The purpose of the present invention is to provide a toner that is highly compatible with fixing rollers and the like.

Another object of the present invention is to provide a toner that does not easily peel off from the transfer paper surface, has excellent fixing properties, and has excellent offset resistance.

(Means for Solving the Problems) According to the present invention, there is provided a toner containing a fixer WIIJllii and a colorant, the fixer 4! The weight average molecular weight (Mw) of the f-fat satisfies the range of so, ooo to 5,000,000, and the viscosity gradient (absolute value) of the toner in the temperature range of 100 to 150°C is 0.030/°C or less A toner characterized in that at least one region is present is provided.

The present invention also provides that there are two regions where the viscosity gradient is 0.030/°C or less, and one region has a temperature of 115 to 125.
℃ range, and other areas have a temperature of 130 to 140 degrees Celsius.
A toner is provided which is characterized in that it exists in a range of degrees Celsius.

The invention can further be characterized by spherical toner particles formed by suspension polymerization.

Note that the viscosity gradient of the toner indicates the ratio of the logarithm of the viscosity to the temperature. For this reason, the temperature difference (X
The amount of change in viscosity with respect to +Δ)−X'C is log(Y+Δ
) pois -1ozY pois, the viscosity gradient is expressed by the formula %) ''(log(Y+△)/Y)/Δ℃.K is in a monotonically decreasing relationship as the temperature increases. , the measurement of viscosity is the viscosity measured by a flow tester.

(Function) In the present invention, it is important that the weight average molecular weight (aw) of the fixing resin in the toner satisfies the range of so, ooo to 5,000,000. The fixing roller and the like of the device are generally heated to a temperature of about 180° C., and act on the resin in the actual toner particles at a temperature in the range of 100° C. to 150° C. during fixing. When the weight average molecule t (Mw) of the fixing resin is within the above range, the toner particles are appropriately melted during fixing,
In addition, permeability and cohesiveness suitable for fixing properties can be maintained.

In the present invention, in addition to satisfying the weight average molecular weight (Mw) range of the fixing resin, the average viscosity gradient (absolute value) of the toner in the temperature range of 100 to 150°C is 0.030/°C or less, Particularly preferably 0.026/
It is important that there is at least one region that is less than or equal to ``C.''

The viscosity of the toner monotonically decreases as the fixing resin gradually melts as the temperature rises, and the viscosity gradient takes a negative value. Therefore, it is understood that the variation in viscosity due to temperature is affected by the absolute value of the viscosity gradient, and if the absolute value is large, the viscosity change with respect to the temperature of the toner becomes large. In the present invention, 111
As shown in the figure, the average viscosity gradient of the toner is 0.030/℃
There is at least one area where: During toner fixing, the toner is heated for a short period of time by a fixing roller at approximately 180°C. This heating heats the toner to 100°C.
The resin starts melting from the vicinity, and when it is in an appropriate melted state, the resin penetrates into the transfer paper, and when the fixing roller is separated, it exhibits a certain cohesive force and anchor effect, and is well fixed on the transfer paper side.

In this case, if the aforementioned slow region exists in the viscosity gradient of the toner, the toner is often maintained at a constant viscosity during fixing. In other words, this means that even if the toner is heated by the high-temperature fixing roller and the temperature is rising, the viscosity of the toner is maintained at a predetermined value more often than with conventional toners. . The details of how maintaining this viscosity value affects permeability, cohesiveness, and anchoring effect during toner fixation are unknown, but it is important that the toner on the transfer paper has fixation properties. However, since hot offset and cold offset do not occur in the toner, it is understood that keeping the viscosity as unchanged as possible will appropriately achieve the permeability, cohesiveness, and anchoring effect of the toner during fixing.

It is understood that some of the fixing resin components of the toner of the present invention exhibit different physical properties, and in a region where the toner has a steep viscosity gradient, the fixing resin decreases the viscosity characteristics of the entire toner by increasing the temperature. In the temperature range where the viscosity gradient is slow, the molten state changes by increasing the temperature, but the viscosity characteristics of the toner as a whole do not change much.
I! It is understood that it is used as a fat component. Therefore, compared to conventional toner, even if the heating conditions of the fixing roller change, the toner is not affected in any way, and its fixing properties are improved and offset resistance is improved.

Further, in the present invention, it is more desirable to obtain the toner by a suspension polymerization method. The suspension polymerization method has the advantage of improving fluidity because the toner particle size can be made relatively uniform and the particles can be made into particles that are close to perfect spheres. Moreover, as shown in FIG. 2, it can be formed in a state in which a low molecular weight substance and a high molecular weight substance are present in the fixing INl resin. Such a molecular weight distribution of the fixing resin improves the relationship between the melt state and the viscosity state, and has a positive effect on fixing properties and anti-offset properties.

Suspension polymerization involves suspending vinyl monomers, colorants, or other ingredients that can become a fixing agent.

This is carried out by using initiators and crosslinking agents that have a defined half-life. By such polymerization method,
It is possible to satisfy the above-mentioned weight average molecular weight (M) range of the fixing resin and to obtain a viscosity change gradient within the above range of the toner particles.

(Preferred Embodiments of the Invention) Preferred embodiments of the present invention will be described in detail below.The toner of the present invention comprises a fixing resin, a colorant, and if necessary, a charge control agent, a magnetic material, and other materials.

In the fixing resin used in the present invention, those having an ethylenically unsaturated bond are used alone or in combination of two or more.

Suitable examples of such monomers include monovinyl aromatic monomers, acrylic monomers, vinyl ester monomers, vinyl ether monomers, diolefin monomers, and monoolefin monomers. body etc.

As a monovinyl aromatic monomer, in the formula, R3 is a hydrogen atom, a lower alkyl group, or a halogen atom, and R2 is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, an amino group, a nitro group, a vinyl group, or It is a carboxyl group.

monovinyl aromatic hydrocarbons such as styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene,
o-m-p-chlorostyrene, p-ethylstyrene, sodium styrene sulfonate, divinylbenzene alone or in combination of two or more, and other monomers mentioned above include the following, respectively: Can be mentioned.

Formula % Formula % (2) Sil, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, 3-ethyl hydroxyacrylate, γ-propyl hydroxyacrylate, δ- Butyl hydroxyacrylate, β-hydroxyethyl methacrylate, γ-aminopropyl acrylate, γ-N, N
-diethylaminopropyl acrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, etc.

Formula % Formula % In the formula, R3 is a hydrogen atom or a lower alkyl group, and R4 is a hydrogen atom or a hydrocarbon group having up to 12 carbon atoms.

Acrylic monomers which are hydroxyalkyl, vinyl ester or aminoalkyl groups, such as acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhex acrylate 0-C- R.

...(3) where R5 is a hydrogen atom or a lower alkyl group, vinyl esters such as vinyl formate, vinyl propionate, vinyl propionate, etc.

formula, CH2=CH chloroprene, etc.

formula.

l0 O-R2 ...(4) CL = C-R.

...(6) where R5 is a monovalent hydrocarbon group having up to 12 carbon atoms, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl-n-butyl ether, vinyl phenyl ether, vinyl cyclohexyl ether, etc. .

Formula % Formula % (5) In the formula, each of R, , R, , R, is a hydrogen atom, a lower alkyl group, or a halogen atom.

diolefins, especially butadiene, in the isopre formula, R
Each of 7° and R1 is a hydrogen atom or a lower alkyl group. Examples include monoolefins such as ethylene, propylene, isobutylene, butene-1, pentene-1,4-methylpentene-1, and the like.

It is important that the weight average molecular weight (Mw) of the fixing resin made of such resin components satisfies the range of 50,000 to 5,000,000, particularly 100.000 to 2,000,000. The fixing roller etc. of the device used in the present invention are as follows.

Generally, it is heated to a temperature of about 180°C, and acts on the resin in the actual toner particles at a temperature in the range of 100 to 150°C during fixing. If the weight average molecular weight (Mw) of the fixing resin is smaller than the above range, the toner particles made of the fixing resin will quickly melt during fixing and will extremely lose viscosity, making hot offset apt to occur. On the other hand, if the weight average molecular weight (Mw) of the fixing resin is larger than the above range, the toner particles will have a large amount of insoluble portions and cold offset will easily occur.

Also, what is the distribution of the weight average molecular weight (M%I) of the fixing resin?
! It is further desirable to have two peaks as shown in 211ii1. That is, it is desirable that low molecular weight polymers and high molecular weight polymers coexist. Also.

Among the molecular weight peaks of the polymer, the minimum peak molecular weight value is 50,000 or less, preferably 3,000 to 5
0,000, particularly preferred, <5,000 to 40,0
00 and the maximum peak molecule Jim, 6 (20
0,0001X top 1. Preferably L<Li2O2,000 to 7,000,000. Particularly preferably 300.000
5,000,00 (1) Ii Surroundings. A fixing resin having a molecular weight distribution within the above range further improves toner fixing properties, offset resistance, blocking resistance, and abrasion resistance. Moreover, it has a great influence on obtaining a suitable viscosity change gradient in the temperature range described below. In addition, it is desirable that a high molecular weight component having a molecular weight equal to or higher than the maximum molecular weight peak exists in the range of 10 to 40% based on the total weight, so that blocking resistance and durability can be improved, and stable performance can be obtained over a long period of time. can.

As the coloring agent used in the present invention, dyes and pigments known per se are used, and specific examples thereof can be shown below.

a. Black pigments carbon black, acetylene black, lamp black, aniline black.

b, yellow pigment yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navels yellow, naphthol yellow S, Hansa yellow 10G, benzidine yellow G, quinoline yellow lake, permanent yellow NGO, tart Radin rake.

C2 orange pigment red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, palkan orange, indanthrene brilliant orange RK, benzidine orange q, indanthrene brilliant orange GR.

d, red pigment red pigment, cadmium red, red lead, mercury cadmium sulfide, burnent orange 4R, lithol red, pyrazolone red, watching red calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizarin Lake, Brilliant Carmine 3B.

e, purple pigment manganese violet, fast violet B, methyl violet lake.

f, blue raw material navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue metal-free phthalocyanine blue phthalocyanine blue partially chlorinated product,
First Sky Blue, Indance Tremble-BC.

g, green pigment chrome green a chromium, pigment green B,
Malachite Green Lake, Fanal Yellow Green G.

h, white pigment Zinc white, titanium oxide, antimony white, zinc sulfide.

i9 extender pigment Palite powder, barium carbonate, clay, silica.

White carbon, talc, aluminum white.

These colorants can be added in an amount of 1 to 20 parts by weight, particularly preferably 5 to 15 parts by weight, per 100 parts by weight of the fixing resin component.

Components other than the colorant used in the present invention include a magnetic material, a charge control agent, and the like as appropriate.

As the magnetic material pigment, for example, triiron tetroxide (Fe304
), iron sesquioxide (y -Fe203), iron zinc oxide (Z
nFe204), iron yttrium oxide (Y3FesO+
2), iron cadmium oxide (Gd, Fe, 0.2), I
I2 steel (CuFe204), iron oxide complex (PbFe+
20+*), neodymium iron oxide (NbFe0s), barium iron oxide (BaFe120..), magnesium iron oxide (NgFe204), manganese iron oxide (MnFe20)
4), lanthanum iron oxide (LaFe0.), iron powder (Fe
), cobalt powder (Co), nickel powder (Ni), etc. are known.

In the present invention, any of these known fine powders of magnetic materials can be used.

In addition, in order to adjust the chargeability of the toner, a charge control agent known per se, such as a metal-containing azo dye, (alkyl)
Metal compounds of salicylic acid, metal soaps of naphthenic acid, fatty metal soaps, resin acid soaps, etc. can also be blended. These charge control agents are 0 per 100 parts by weight of polymerizable monomer.
．． 1 to 10 parts by weight can be used, particularly preferably 0.5 to 5 parts by weight. Further, in order to provide an offset prevention effect to the toner, a release agent such as low molecular weight polyethylene, low molecular weight polypropylene, various waxes, silicone oil, etc. can be included. These offset inhibitors are preferably used in an amount of 0.1 to 10 parts by weight, particularly preferably 0.5 to 8 parts by weight, per 100 parts by weight of the polymerizable monomer.

For toner particles composed of the above components, the viscosity was measured using a flow tester at a temperature of 100 to 1.
In the range of 50℃, the viscosity gradient increases by 5X by heating.
It is desirable to use a material in which the temperature difference Δ required to change from 106 poise to 5X 10' poise is 32°C or more, particularly 35°C or more. A toner having characteristics in this range has little change in viscosity with respect to temperature, which means that the viscosity does not change abruptly due to temperature change during fixing.

In the present invention, the viscosity gradient (absolute value) of the toner is 0.03 in the temperature range of 100 to 150°C.
It is important that there is at least one region where the viscosity gradient of the toner is below 0.0/"C, particularly preferably below 0.026/"C. However, the fixing properties and anti-offset properties of the toner are not improved.

FIG. 111 is a characteristic diagram showing the relationship between temperature and viscosity of the toner according to the present invention. As shown in FIG. 1, the viscosity change curve A of the toner of the present invention has a slope of -0,014/°C in the temperature range of 115 to 125°C, and a slope of -0,014/°C in the temperature range of 130 to 145°C.
In the °C region, the slope is -0,025/°C.

On the other hand, the viscosity gradient of the conventional toner curve B is at a temperature of 10
In the range of 0 to 150°C, all values exceed 0.030/°C. Therefore, when the toner particles of the present invention are heated by the fixing roller, the viscosity does not change and the viscosity is maintained at a predetermined level. Penetration, which changes rapidly and is a factor in fixation and offset resistance,
Affects cohesion and anchoring effects.

The present invention also includes: As shown in the IF5 diagram, it is preferable that there are two regions where the viscosity gradient (absolute value) is 0.030/°C or less. For example, if the first area is 115 to 125
Exists in the temperature range of 130 to 140 degrees Celsius in other regions
temperature range. A toner having such viscosity characteristics has good permeability into the transfer paper, has good cohesion when the fixing roller is separated, increases fixing properties, and the transfer toner does not easily separate from the transfer paper. There is no dirt on the fixing roller, and no offset or the like is observed.

In manufacturing the toner of the present invention, a known method can be used, and the weight average molecular weight (Hw) of the fixing resin
is selected to fall within the above range, and the fixing resin, colorant, and other materials are melt-kneaded and pulverized so that the toner particles have a viscosity change gradient within the above range in the above temperature range. You can get it by doing Further, in the present invention, it is more desirable to directly obtain toner particles by a suspension polymerization method in addition to a kneading method.

The suspension polymerization method has the advantage that toner particle sizes can be made relatively uniform, and particles can be made into particles that are close to perfect spheres. In addition, the coloring agent, mold release agent, etc. are incorporated into the polymer chain, and the ingredients do not separate, resulting in excellent durability and fluidity.

Furthermore, as described above, the fixing resin shown in FIG. 2 can be formed in a state in which a low molecular weight substance and a high molecular weight substance are present.

Suspension polymerization is carried out by suspending vinyl monomers, colorants, or other ingredients that can become fixing resins, and adding an initiator and crosslinking agent with a predetermined half-life. .

(A polymerization initiator #I agent A polymerization initiator is used in the suspension polymerization of the present invention, and a specific example of the polymerization initiator is 2,2-azobis(2,4
-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvalero Azo compounds such as nitrile, 2,2-azobis(2-cyclopropylpropionitrile), cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide, lauroyl peroxide Radical polymerizable initiators such as peroxides such as In addition, combinations with ionizing radiation such as γ-rays and accelerated electron beams, and various sensitizers are also used.

In addition, the amount of polymerization initiator such as an azo compound or peroxide may be a so-called appropriate amount of catalyst, and generally 0.00% per monomer charged.
．． It is preferred to use amounts of 1 to 30% by weight, especially 2 to 20% by weight. Among the polymerization initiators used in the present invention, at least one initiator having a half-life of 30 minutes or less at a temperature of 80° C. is used in suspension polymerization. The half-life of 30 minutes or less means the half-life under the influence of a single polymerization accelerator when the polymerization accelerator is included.

(8) Crosslinking agent: A crosslinking agent is added during suspension polymerization to promote polymerization of vinyl monomers. The amount of the crosslinking agent to be used is desirably in the range of 0.01 to 50% by weight, particularly 0.1 to 10% by weight, based on the monomers charged.

Examples of crosslinking agents include divinyl compounds such as divinylbenzene, divinyl ether, and divinyl sulfone, diallyl compounds such as allyl phthalate and diallyl carbinol, diacrylic esters such as diacrylphenol, ethylene glycol dimethacrylate, and trimethylol. Any known per se such as propane triacrylate, glycidyl methacrylate, glycidyl acrylate, etc. can be used, but diacrylic esters are particularly preferred.

(C) Other compounding agents used in the polymerization step: In the present invention, polymerization accelerators, crosslinking agents, or chain transfer agents may be used as necessary, and these may be known per se, and are added in appropriate amounts. be able to.

Furthermore, in the polymerization step of the present invention, surfactants and dispersants known per se may be added in order to perform granulation and the like well.

In suspension polymerization, the dispersion medium is usually water-soluble;
Water, alcohol, etc. are used. The vinyl monomer is usually suspended in the dispersion medium in an amount of 50 to 500 g per liter of the dispersion medium, although it varies depending on the type. During cloudy granulation, surfactants and dispersion stabilizers are used.
Known surfactants can be used, but it is particularly desirable to use fatty acid-based or sulfonic acid-based anionic surfactants as surfactants, and sparingly soluble inorganic salts as dispersion stabilizers. is desirable.

Granulation in a dispersion medium during suspension polymerization is performed using a homomixer.
This is carried out using a high-speed shear stirrer such as a homogenizer, and the granulation size is preferably in the range of 0.1 to 50 μm, particularly 3 to 20 μm.

By setting the granulation diameter within the above range, toner particles of an appropriate size can be obtained.

During suspension polymerization, at least one type of initiator with a half-life of 30 minutes or less, a slow polymerization initiator, a crosslinking agent, etc. are also blended as described above. These blends are suitably carried out before or after granulation.

The reaction temperature is preferably 30 to 100°C, particularly 4o to 90°C. Further, in the present invention, the reaction temperature may be changed during the reaction.

Examples are shown below.

(Example) Examples are shown below. Note that the scope of the present invention is not limited to the scope of the examples.

(Example 1) Prescribe the toner ingredients shown below and make a toner! I
did.

Styrene 85 parts by weight 2-ethylhexyl methacrylate 15 parts by weight Carbon black, N^-1007 parts by weight (manufactured by Mitsubishi Chemical Corporation, trade name) Charge control agent, Bontron 5-40 0.5 parts by weight (manufactured by Orient Corporation, trade name) name) divinylbenzene 1.1tffi part polymerization initiator, 2,2'-azobis(4-methoxy2,4-
7 parts by weight of dimethylvaleronitrile) These mixtures were added to a continuous phase prepared by adding 6 parts by weight of tricalcium phosphate and 0.01 parts by weight of sodium dodecylbenzenesulfonate to 400 parts by weight of water.

It was granulated using a homomixer and polymerized at 80"C for 8 hours.The resulting polymer was treated with dilute acid, washed with water,
After drying, toner particles were obtained.

As a result, when the particle size characteristics were measured using a Coulter counter, the median diameter on a volume basis was found to be:

had a sharp particle size distribution of 11.1 μm.

In addition, when the molecular weight distribution was measured by GPC, the second
As shown in the figure, it has multiple peaks, the overall weight average molecular weight (Mw) is 840,000, the largest peak on the high molecular side is at 2,300,000, and the highest peak on the low molecular side The peak was at the 32,000 position. Furthermore, the proportion of high molecular weight components having a molecular weight equal to or higher than that of the maximum molecular weight peak was 15.6%.

The curve of the viscosity change gradient of toner particles shows a slow monotonous decreasing curve as shown in Figure 311, and at a temperature of 120 to 125
The slope in °C was -0,014/°C. Also, the slope at a temperature of 135 to 140°C is -0,025/"
It was C.

Next, 0.1 part by weight of hydrophobic silica is mixed per 100 parts by weight of the obtained toner, and a carrier in which ferrite particles are coated with silicone resin is mixed with the toner so that the toner concentration is 3%. did. And electrophotographic copying machine D
A 20,000-sheet printing durability test was conducted using C-1205 (manufactured by Sanda Kogyo Co., Ltd., product name).

The fixing properties and anti-offset properties were evaluated.

Regarding fixing properties, a transfer paper with a toner image formed thereon is passed through and fixed, an adhesive tape is pressed against the formed fixed image, and then peeled off, and the fixed image is compared before and after peeling off. The density was determined by measurement using a reflection densitometer (manufactured by Tokyo Juishiki), and was evaluated by calculating. Further, staining of the fixing roller was determined by visually observing the fixing roller after printing and by checking the stains on the back of the paper during printing. In addition, offset resistance was evaluated based on whether an offset phenomenon occurred during continuous copying. Regarding blocking resistance, put 20g of toner in a glass cylinder with an inner diameter of 26.5mm in an oven at 60°C, place a 100g weight on the toner,
The toner was left to stand for 0 minutes, and then the cylinder was removed and evaluated by whether the toner crumbled. The results are shown in Table 1.

(Example 2) Styrene 85 parts by weight 2-ethylhexyl methacrylate Divinylbenzene 1.1 parts by weight 2-ethylene glycol dimethacrylate 2.7 parts by weight Polymerization initiator, 2,2'-azobis(4-methoxy 2° 4
-dimethylvaleronitrile) 7 parts by weight A mixture of these was polymerized in the same manner as in Example 1 to synthesize suspension polymerized resin particles.

100 parts by weight of the obtained suspension polymerized resin particles, 7 parts by weight of carbon black (MA-100 manufactured by Mitsubishi Kasei Corporation), and 0.5 parts by weight of a charge control agent (Bontron 5-40 manufactured by Orient Corporation) were mixed and heated at 150°C. The mixture was melt-kneaded on a roll mill before and after. After cooling this kneaded material, it was pulverized with an air jet mill and subjected to air classification to obtain a volume-based median diameter of 10.4.
A μm toner was obtained.

When the viscosity change of this toner particle was measured, it showed a curve similar to that shown in FIG.

Next, a developer was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

15 parts by weight (comparative example) 100 parts by weight of a styrene-acrylic copolymer having a molecular weight distribution as shown in Figure 2, carbon black (MA-
100 Mitsubishi Kasei Co., Ltd. ml) and 0.5 parts by weight of a charge control agent (Bontron 5-40 manufactured by Orient Corporation) were mixed and melt-kneaded on a roll mill at around 150°C. After cooling this mixture, it is pulverized with an air jet mill,
Air classification was performed to obtain a toner having a volume-based median diameter of 11.3 μm.

The curve of the viscosity change gradient of the toner particles is a monotonically decreasing curve as shown in Figure 111, and the viscosity gradient changes from temperature 115 to 1
All values exceeded 0.030/°C in the range of 45°C.

Next, a developer was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Table-1 In the table, 0190% when fixability is maintained at 95% or more
If the above value was maintained, it was evaluated as Δ, and if it fell below 90%, it was evaluated as ×. In addition, the blocking resistance was evaluated as ○ if the cylinder collapsed as it was when the cylinder was removed, Δ if it collapsed when pressed with a finger, and X if it did not collapse.

(Effects of the Invention) According to the present invention, the weight average molecular weight (
Mw) satisfies a certain range, and the temperature is 100 to 150℃
In the range of 0.030/°C or less, we set a region where the viscosity change gradient (absolute@) of toner particles was 0.030/°C or less.
During fixing, the toner is not affected by the heating conditions of the fixing roller, and its melting and viscosity are within an appropriate range, allowing the resin to easily penetrate the transfer paper.

It has a certain degree of cohesiveness and anchoring effect. Therefore, the toner has good fixability to the transfer paper, and the toner does not peel off from the transfer paper, and offset hardly occurs.

Therefore, the toner has excellent compatibility with the fixing device.

[Brief explanation of drawings]

FIG. 111 is a characteristic diagram showing temperature and viscosity changes of toner particles according to the present invention, and FIG. 2 is a characteristic diagram of molecular weight distribution of toner particles according to the present invention.

Claims (3)

[Claims] (1) A toner containing a fixing resin and a colorant,
The fixing resin has a weight average molecular weight (Mw) in the range of 50,000 to 5,000,000 and a temperature of 100
A toner characterized in that there is at least one region in which the viscosity gradient (absolute value) of the toner is 0.030/°C or less in the range of 150°C to 150°C. (2) There are two regions where the viscosity gradient is 0.030/°C or less, one region has a temperature in the range of 115 to 125 °C, and the other region has a temperature in the range of 130 to 140 °C. The toner according to claim 1, wherein the toner is present. (3) The toner according to claim 1 or 2, which is a spherical toner particle formed by suspension polymerization.