JP2007334055A - Image forming apparatus and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus using an image formation toner which has high heat resistance while ensuring low-temperature fixability and stably gives good images, even in an operating environment in which a fixing device with a fixing roller having low surface pressure is used and much heat stress is applied to a developer because of long stirring time in development. <P>SOLUTION: The electrophotographic image forming apparatus has the toner containing at least a binder resin, wax and a colorant and uses oilless fixing in which surface pressure (roller road/contact area) value in fixing is ≤1.5×10<SP>5</SP>Pa, wherein a developer used in the image forming apparatus comprises a carrier and the toner, and when the toner is observed with a transmission electron microscope, the area ratio of the wax in an internal region of the toner from a surface thereof to 1 μm depth is 10-40%. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrophotographic image forming apparatus and a toner used for the development thereof, and more particularly to a technique of wax in the toner.

  Conventionally, as an electrophotographic method, a photoconductive substance is generally used, an electric latent image is formed on a photoreceptor by various means, and then the latent image is developed using toner, and if necessary, After the toner powder image was transferred to paper or the like, it was fixed by heating, pressing or solvent vapor to obtain a copy image.

  In order to heat and fix a toner image on a transfer paper, heat roller fixing is widely used because of its energy efficiency. In recent years, energy saving has further progressed, and there is also an image forming apparatus that cuts off the heat source during standby without fixing. In such an apparatus, the heat roller is heated immediately after the heat source is turned on, and it is necessary to increase the thermal energy efficiency so as to reach the desired temperature in a very short time. Therefore, the thickness of the fixing roller on the side in contact with the toner image support surface Attempts have been made to reduce the thickness. This makes it possible to reach the desired temperature in a very short time.

  However, by reducing the thickness of the fixing roller, the mechanical strength of the roller itself is weakened, and a large load cannot be applied between the rollers. In order to actually operate such a fixing device without any trouble, the toner must realize low-temperature fixing that is not comparable to conventional toner. In recent years, the need for low-temperature fixing has further increased, and when a thin-walled, low-load fixing device as described above is actually used, sufficient low-temperature fixing properties, ensuring a fixing temperature range, and heat It becomes difficult to balance storage.

On the other hand, attempts have been made to improve low-temperature fixability by using a resin or wax having a low softening point for the toner used for low-temperature fixing as described above (see, for example, Patent Document 1). In particular, the amount of wax on the toner surface greatly affects the releasability of the toner during fixing.
JP 2002-304006 A

However, if the amount of the wax exposed on the toner surface is large, the releasability by the wax is increased by heating at the time of fixing, which is effective in terms of offset resistance, but at the same time, the wax is spent on the carrier or photosensitive. There is a problem in that it is difficult to obtain a good image quality by shifting to a body or a developing sleeve to cause filming. Furthermore, since such a low-temperature fixing toner is thermally weak, it is known to cause so-called blocking, which is hardened by the heat of the machine used or the heat during storage.

  Recently, many copiers have a printer function added, and the output of a single copy or print has increased, and the developer agitation time has increased with respect to the number of copies and prints. . In particular, in the case of the “1 to 1 copy (low duty mode)” mode, which is one copy per original for machine usage, the development rotation time per copy for continuous copying is 2-8. Double the rotation time. In such a mode, the thermal stress generated between the developer and the developer regulating member also increases when the developer is agitated, and in addition to blocking, the toner spends on the carrier, shortening the life of the agent. Such as filming on the photoconductor and the like.

  In addition, the need for low-temperature fixing in recent years has further increased, and when the above-described low surface pressure fixing device is used in an environment where the developer agitation time is long, the conventional technology has sufficient low-temperature fixing ability. It is difficult to achieve both the securing of the fixing temperature range and high heat resistance.

  The present invention has been made in view of the above-described circumstances, and has low temperature fixability even in a use environment where a developing agitation time having a fixing device using a low surface pressure fixing roller is long and a thermal stress on the developer is large. An object of the present invention is to provide an image forming toner which has high heat resistance while ensuring and can stably obtain a good image.

The invention according to claim 1 is an oil-less toner having toner containing at least a binder resin, a wax, and a colorant, and having a surface pressure (roller load / contact area) of 1.5 × 10 ⁵ Pa or less during fixing. An electrophotographic image forming apparatus using fixing, wherein a developer used in the image forming apparatus includes a carrier and the toner, and the toner includes a toner containing at least a wax and a binder resin, and a toner and a carrier. Thus, the image forming apparatus uses toner in which the ratio of the area occupied by the wax in the region from the toner surface to the inside of 1 μm when the toner is observed with a transmission electron microscope is in the range of 10 to 40%.

  According to a second aspect of the present invention, in the apparatus according to the first aspect, among the waxes dispersed in the toner, the dispersed wax existing in the vicinity of the toner surface is 70% by number or more of the total wax. It is characterized by.

  According to a third aspect of the present invention, in the apparatus according to the first or second aspect, the dispersed wax existing dispersed in the toner is not substantially exposed on the surface of the toner. .

  According to a fourth aspect of the present invention, in the apparatus according to any one of the first to third aspects, 60 dispersed particles of wax dispersed particles having a dispersed wax diameter of 0.5 to 3 μm existing inside the toner are provided. Occupy the above.

  According to a fifth aspect of the present invention, in the apparatus according to any one of the first to fourth aspects, the wax is at least one wax selected from a liberated fatty acid carnauba wax, rice wax, and a montan wax. Is used.

  According to a sixth aspect of the present invention, in the apparatus of the fifth aspect, the toner used is a dispersion of at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an organic solvent. The toner material liquid is a toner obtained by subjecting at least one of a crosslinking reaction or an extension reaction in an aqueous medium.

  According to a seventh aspect of the present invention, in the apparatus of the sixth aspect, the toner used is a dispersion of at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an organic solvent. The toner is obtained by subjecting the toner material liquid to at least one of a crosslinking or elongation reaction in an aqueous medium.

  According to an eighth aspect of the present invention, in the apparatus according to the seventh aspect, the shape of the toner is a spindle shape.

  According to a ninth aspect of the present invention, in the apparatus according to the eighth aspect, the ratio (r2 / r1) of the major axis r1 to the minor axis r2 of the toner is 0.5 to 0.8, and the thickness r3 and the minor axis. The ratio to r2 (r3 / r2) is represented by 0.7 to 1.0.

According to the present invention, an oil-less fixing having a toner containing at least a binder resin, a wax, and a colorant and having a surface pressure (roller load / contact area) of 1.5 × 10 ⁵ Pa or less at the time of fixing. In the electrophotographic image forming apparatus used, the developer comprises a toner containing at least a wax and a binder resin and a carrier, and the wax in the region from the toner surface to the inside of 1 μm when the toner is observed with a transmission electron microscope The image forming apparatus is characterized by using a toner with an area ratio of 10 to 40%, and in a use environment where fixing with a low surface pressure causes a long stirring time for development and a large amount of thermal stress on the developer. In addition, it is possible to provide an image forming apparatus that has high heat resistance while ensuring low temperature fixability and can stably obtain a good image.

  Hereinafter, an image forming apparatus and a toner according to an embodiment of the present invention will be described in detail with reference to the drawings. The embodiments described below are preferred embodiments of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. As long as there is no description which limits, it is not restricted to these aspects.

  An example of a fixing device used in an image forming apparatus according to an embodiment of the present invention is shown in FIG. As shown in FIG. 1, 1 represents a fixing roller, and 2 represents a pressure roller. The fixing roller 1 has an RTV silicone rubber (room temperature curable silicone), tetrafluoroethylene-perfluoroalkyl vinyl ether (PTFE-PFA) on the surface of a metal cylinder 3 made of a high thermal conductor such as aluminum, iron, stainless steel or brass. ), An offset prevention layer 4 such as polytetrafluoroethylene (PTFE).

  A heating lamp 5 is disposed inside the fixing roller 1. The metal cylinder 6 of the pressure roller 2 is often made of the same material as that of the fixing roller 1, and the surface thereof is covered with an offset prevention layer 7 such as PFA or PTFA. Further, a heating lamp 8 can be arranged inside the pressure roller 2.

  Although the fixing roller and the pressure roller are not shown, they are pressed against and rotated by springs at both ends. A fixing support S (for example, transfer paper such as paper) of the toner image T is passed between the fixing roller 1 and the pressure roller 2 for fixing.

  The fixing device used in the present invention improves the temperature rise characteristic of the fixing roller by setting the thickness of the metal cylinder of the fixing roller to 1.0 mm or less, and can rise to a desired temperature in a very short time. Can do. The preferred thickness of the metal cylinder varies depending on the strength and thermal conductivity of the material used, but is preferably 0.2 to 0.7 mm, for example.

Further, the load (surface pressure) applied between the fixing roller and the pressure roller is preferably 1.5 × 10 ⁵ Pa or less. Here, the surface pressure is a value obtained by dividing the load applied to both ends of the roller by the roller contact area. The image forming apparatus of the present invention has the above-described fixing device. In addition, a photosensitive member, a charging device, an exposure device, a developing device using toner, a recording medium such as paper developed by developing with a developing device, and an image is formed on a fixing device. It has a means to convey. These may be known ones and can be used without particular limitation.

The roller contact area is such that an OHP sheet such as an OHP sheet is passed between rollers heated to a fixing temperature, stopped on the way, held for several tens of seconds, and then discharged to change the surface property. Find the area of the location. A higher roller surface pressure is advantageous for fixing a toner image. However, in the fixing device in which the thickness of the metal cylinder of the fixing roller is 1.0 mm or less, a large load is not applied because the roller is distorted. The load is 1.5 × 10 ⁵ Pa or less, preferably 0.5 to 1.0 × 10 ⁵ Pa.

  Next, materials used for the toner according to the exemplary embodiment will be described in detail. In this embodiment, the present inventors have found a toner in which wax particles are stably dispersed with an appropriate particle size in the toner. This is presumably because the binding part of the polar group in the toner binder causes negative adsorption at the interface with the wax, and the low polarity wax is stably dispersed.

  Furthermore, in particular, in a method in which a toner composition is dissolved / dispersed in an organic solvent and dispersed in an aqueous medium to obtain toner particles, a highly polar bond portion shows a slight affinity with water and is near the toner surface. However, the effect of preventing the wax particles from being exposed to the surface is also exhibited. Of the wax present in the toner, the area occupied by the wax present in the region from the toner surface to 1 μm inside is 10 to 40%. In particular, the number of waxes in the vicinity of the toner surface is 70. When dispersed, it is possible for sufficient wax to ooze out during fixing, ensuring releasability and reducing the amount of wax present on the outermost surface of the toner. It is possible to prevent the wax from transferring.

  In particular, a dense magnetic brush is formed in the nip region where the magnetic brush rubs against the photoreceptor, and this effect is significant under development conditions in which a thermal and mechanical load is applied by the development process. The occurrence of “missing” can be prevented and a good image can be obtained stably over a long period of time.

  When the area occupied by the wax existing in the region up to 1 μm from the surface of the toner is less than 10%, the releasability may be insufficient, and when the area is more than 40% The filming on the photosensitive member and the developing sleeve may be remarkably deteriorated.

  The distribution of the wax dispersion diameter present in the toner of the present invention is 70% by number or more, more preferably 70% by number or more of particles of 0.5 to 3 μm, and more preferably 70% by number or more of particles of 1 to 2 μm. If there are many particles smaller than 0.5 μm, sufficient releasability cannot be expressed. On the other hand, when there are many particles larger than 3 μm, not only the aggregation property is exhibited and the fluidity is deteriorated or filming is caused, but also color reproducibility and glossiness are remarkably lowered in the color toner.

(Measurement of wax, existence state and dispersion diameter)
In the present invention, the particle diameter in the maximum direction of the wax is defined as the wax dispersion diameter. Specifically, the toner is embedded in an epoxy resin, cut into an ultrathin section of about 100 μm, dyed with ruthenium tetroxide, and then the cross section of the toner is observed with a transmission electron microscope (TEM) at a magnification of 10,000 times. Images were taken and 20 photographs (20 toners) were evaluated to observe the dispersion state of the wax and the dispersion diameter was measured.

  The area ratio of the wax in the region from the toner surface to the inside of 1 μm is obtained by the area ratio of the wax ratio in the region of the toner surface and the region from the surface to 1 μm. The wax that does not exist on the toner surface but is in the vicinity of the toner surface means that the surface of the toner is more than the curve connecting the middle part of the distance between the toner particle surface and the central part (the halfway point). Indicates what is on the side. However, when the wax exists on the curve connecting the middle part of the distance between the surface and the center part, it is determined that the wax exists on the center side.

  In this embodiment, it is effective to use carnauba wax, rice wax, or ester wax as the wax dispersed in the toner. These waxes are excellent in low-temperature fixability compared to other waxes.

  Carnauba wax is a natural wax obtained from the leaves of carnauba palm, but especially low-acid-value types from which free fatty acids have been eliminated can be uniformly dispersed in the binder resin, and further because there are few volatile components, the photoconductor This is particularly preferable because the filming to the film and the spent on the charge imparting member are small. Rice wax is a natural wax obtained by refining crude wax produced in a dewaxing or wintering process when refining rice bran oil extracted from rice bran. Synthetic ester wax is synthesized by ester reaction from monofunctional linear fatty acid and monofunctional linear alcohol. These wax components are used alone or in combination. The added amount of the wax component is preferably 0.5 to 10 parts by weight.

  In particular, the content of the wax is generally in the range of 1 to 10 parts by weight with respect to the toner resin component. In the present invention, it is preferably 5 parts by weight or less, more preferably 1 to 5 parts by weight. When the amount is less than 1 part by weight, the effect as a release agent is not sufficient, and when the amount exceeds 5 parts by weight, the amount of wax exposed to the toner surface increases, so the spent on the carrier and the fill on the photoreceptor are increased. Ming easily occurs.

  Particularly, since the toner has an average volume particle diameter of 5 to 10 μm and a toner content of 5 μm or less is 60 to 80% by number, it has good fixability even in a use environment where there is a lot of thermal stress. It was found that it was possible to keep a good image. When the content of toner of 5 μm or less is 60% by number or less, image quality stability such as fine line reproducibility may deteriorate. On the other hand, when the content of the toner of 5 μm or less is 80% by number or more, the homogenization of the toner is impaired, the charging stability may be deteriorated, and the image density may be lowered.

  The toner of the present invention is preferably spindle-shaped. An irregular shape or a flat shape having a non-constant toner shape has the following problems due to poor powder flowability. Since frictional charging cannot be performed smoothly, problems such as background stains are likely to occur. When developing a minute latent image dot, the dot reproducibility is inferior because it is difficult to obtain a dense and uniform toner arrangement. In the electrostatic transfer method, the transfer efficiency is inferior due to being hardly affected by the lines of electric force.

  When the toner is close to a true sphere, the powder fluidity is too good and excessively acts on the external force, so that there is a problem that the toner particles are likely to be scattered outside the dots during development and transfer. . In addition, since the spherical toner easily rolls on the photosensitive member, there is a problem that the toner often gets into the gap between the photosensitive member and the cleaning member, resulting in poor cleaning.

  In the spindle-shaped toner according to the present embodiment, the powder fluidity is appropriately adjusted. Therefore, the triboelectric charging is smoothly performed and the background dirt is not generated. It is developed in an orderly manner, and then transferred efficiently and has excellent dot reproducibility. In addition, the powder flowability is moderately braked to prevent scattering at that time. The spindle-shaped toner has a limited rolling axis as compared with the spherical toner, and therefore, it is difficult to cause a cleaning defect such as to sink under the cleaning member.

  In the toner according to the exemplary embodiment, the ratio of the major axis to the minor axis (r2 / r1) is 0.5 to 0.8, and the ratio of the thickness to the minor axis (r3 / r2) is 0.7 to 1. A spindle shape represented by 0 is preferable. If the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the separation from the true spherical shape is high, but the cleaning property is high, but the dot reproducibility and transfer efficiency are inferior, resulting in high quality image quality. Disappear. When the ratio of the major axis to the minor axis (r2 / r1) exceeds 0.8, it becomes close to a sphere, and cleaning failure may occur particularly in a low temperature and low humidity environment.

  Further, when the ratio of thickness to short axis (r3 / r2) is less than 0.7, it is close to a flat shape and is less scattered like an irregular toner, but a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the short axis (r3 / r2) is 1.0, the rotating body has the long axis as the rotation axis. By adopting a spindle shape close to this, it is a shape that is neither an irregular shape, a flat shape, nor a true spherical shape. Both shapes have triboelectric chargeability, dot reproducibility, transfer efficiency, scatter prevention, and cleaning properties. The shape satisfies all.

  In addition, r1, r2, r3 can be measured by the following method, for example. That is, the toner is uniformly dispersed and adhered on a smooth measurement surface, and 100 particles of the toner are magnified 500 times by a color laser microscope “VK-8500” (manufactured by Keyence Corporation). The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values.

  The toner suitably used in the image forming apparatus according to the embodiment of the present invention is a toner in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or extending a material solution in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

(polyester)
The polyester is obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound. Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable.

  Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use.

  The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred.

  Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).

  In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group.

  The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation.

  The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  In addition to the unmodified polyester obtained by the above polycondensation reaction, the polyester preferably contains a urea-modified polyester. The urea-modified polyester is obtained by reacting a terminal carboxyl group or hydroxyl group of the polyester obtained by the above polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  Next, as amines (B) to be reacted with the polyester prepolymer (A), a divalent amine compound (B1), a trivalent or higher polyvalent amine compound (B2), an amino alcohol (B3), an amino mercaptan (B4) ), Amino acid (B5), and amino acid block of B1 to B5 (B6).

  Examples of the divalent amine compound (B1) include aromatic diamines (for example, phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane); alicyclic diamines (for example, 4,4′-diamino-3,3′-). Dimethyl dicyclohexyl methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (eg, ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.).

  Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.

  Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the compound (B6) obtained by blocking the amino group of B1 to B5 include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance is deteriorated.

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In addition, in the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator can be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition.

  The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient. In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

(Coloring agent)
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmin Min BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of a master batch or a master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene, or a substituted product thereof, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

(Charge control agent)
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives.

  Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo And pigments and other high molecular compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of the charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, but is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

(Release agent)
As a release agent, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a release agent in the dispersion with the binder resin between the fixing roller and the toner interface. The effect on high temperature offset is exhibited without applying a release agent such as oil. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used.

  Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. . The charge control agent and the release agent can be melt-kneaded together with the master batch and the binder resin, and of course, they may be added when dissolved and dispersed in the organic solvent.

(External additive)
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 ^-3 ~2μm, it is particularly preferably 5 × 10 ^-3 ~0.5μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.

  Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when agitation and mixing are performed using an average particle diameter of both fine particles of 5 × 10 ⁻² μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed to obtain a good image quality that does not cause the release of the fluidity imparting agent from the toner and does not generate firefly, etc., and further reduces the residual toner. It is done.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large.

  However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
(Toner production method)
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release agent in an organic solvent.
The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles.
The aqueous medium may be water alone, or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included.

  The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical.

  Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added. As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohol derivatives Nonionic surfactants such as alanine, dodecyl di (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Examples of the anionic surfactant having a fluoroalkyl group that is preferably used include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C _6- C ₁₁ ) oxy] -1-alkyl (C ₃ -C ₄ ) sodium sulfonate, 3- [ω-fluoroalkanoyl (C ₆ -C ₈ ) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C ₁₁ ~C ₂₀₎ carboxylic acids and metal salts thereof, perfluoroalkyl carboxylic acids (C ₇ ~C ₁₃₎ and metal salts thereof, perfluoroalkyl (C ₄ ~C ₁₂₎ sulfonic acids and metal salts thereof, perfluorooctane Sulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) perfluoroo Tan sulfonamide, perfluoroalkyl (C ₆ ~C ₁₀₎ sulfonamide propyl trimethyl ammonium salts, perfluoroalkyl (C ₆ ~C ₁₀₎ -N- ethylsulfonyl glycine salts, monoperfluoroalkyl (C ₆ ~C ₁₆₎ Examples thereof include ethyl phosphate.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos).

In addition, examples of the cationic surfactant include aliphatic 4 such as aliphatic primary, secondary or secondary amic acid and perfluoroalkyl (C ₆ -C ₁₀ ) sulfonamidopropyltrimethylammonium salt which are right on the fluoroalkyl group. Class ammonium salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (manufactured by Asahi Glass), Florard FC-135 (manufactured by Sumitomo 3M), Unidyne DS-202 ( Daikin-E Industries Co., Ltd.), Mega-Fac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.), etc. .

  The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao), SGP (manufactured by Soken), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.). In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used.

As a dispersant that can be used in combination with the above resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Homopolymers or copolymers such as nitrogen-containing compounds such as imidazole and ethyleneimine, or those having a heterocyclic ring thereof,
Polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl Polyoxyethylenes such as phenyl ester and polyoxyethylene nonylphenyl ester, and celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

(3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group.
This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include tin catalysts such as dibutyltin laurate and dioctyltin laurate.

(4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles.
In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

(5) A charge control agent is injected into the toner base particles obtained above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner.
The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not construed as being limited to these examples.

Toner A
~ Synthesis of organic fine particle emulsion ~
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 83 parts of styrene, 83 parts of methacrylic acid, When 110 parts of butyl acrylate and 1 part of ammonium persulfate were added and stirred at 400 rpm for 15 minutes, a white emulsion was obtained. This was heated to raise the temperature in the system to 75 ° C. and reacted for 5 hours.

  Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours to give a vinyl resin (a copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). An aqueous dispersion [fine particle dispersion 1] was obtained. The volume average particle diameter of [fine particle dispersion 1] measured by LA-920 was 105 nm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The resin component had a Tg (glass transition temperature) of 59 ° C. and a weight average molecular weight of 150,000.

-Adjustment of aqueous phase-
990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7: manufactured by Sanyo Chemical Industries) and 90 parts of ethyl acetate are mixed and stirred. As a result, a milky white liquid was obtained. This is designated as [Aqueous Phase 1].

~ Synthesis of low molecular weight polyester ~
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl Add 2 parts of tin oxide, react at 230 ° C under normal pressure for 8 hours, and further react at 5-15 hours under reduced pressure of 10-15mmHg, then add 44 parts of trimellitic anhydride into the reaction vessel and react at 180 ° C under normal pressure for 2 hours. As a result, [low molecular weight polyester 1] was obtained. [Low molecular polyester 1] had a number average molecular weight of 2500, a weight average molecular weight of 6700, Tg of 43 ° C., and an acid value of 25.

~ Synthesis of intermediate polyester ~
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 And 2 parts of dibutyltin oxide were added, reacted at 230 ° C. under normal pressure for 8 hours, and further reacted at reduced pressure of 10 to 15 mmHg for 5 hours to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, Tg of 55 ° C., an acid value of 0.5, and a hydroxyl value of 51.
Next, 410 parts of [Intermediate polyester 1], 89 parts of isophorone diisocyanate and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained. [Prepolymer 1] had a free isocyanate weight percentage of 1.53%.

~ Synthesis of ketimine ~
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound 1]. The amine value of [ketimine compound 1] was 418.

~ Synthesis of MB (master batch) ~
Add 1200 parts of water, 540 parts of carbon black (Printex 35 Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5], 1200 parts of polyester resin, and mix with a Henschel mixer (Mitsui Mining Co., Ltd.). Was kneaded at 150 ° C. for 30 minutes using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch 1].

~ Creation of oil phase ~
In a container equipped with a stir bar and a thermometer, 378 parts of [low molecular weight polyester 1], 110 parts of ester wax (acid value 3), 22 parts of CCA (salicylic acid metal complex E-84: Orient Chemical Industries), 947 parts of ethyl acetate Was heated to 80 ° C. with stirring, maintained at 80 ° C. for 5 hours, and then cooled to 30 ° C. over 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain [Raw material solution 1].

  [Raw Material Solution 1] Transfer 1324 parts to a container and use a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.) to feed 1 kg / hr of liquid, 6 m / sec of disk peripheral speed, and 80% by volume of 0.5 mm zirconia beads. Carbon black and wax (WAX) were dispersed under conditions of filling and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by one pass with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1]. The solid content concentration of [Pigment / WAX Dispersion 1] (130 ° C., 30 minutes) was 50%.

~ Emulsification⇒Desolvation ~
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container, and TK homomixer (manufactured by Tokushu Kika) for 1 minute at 5,000 rpm After mixing, 1200 parts of [Aqueous phase 1] was added to the container, and mixed with a TK homomixer at 13,000 rpm for 20 minutes to obtain [Emulsified slurry 1]. [Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C for 8 hours, aging was carried out at 45 ° C for 4 hours to obtain [Dispersion slurry 1]. [Dispersion Slurry 1] had a volume average particle size of 5.99 μm and a number average particle size of 5.70 μm (measured with Multisizer II).

~ Washing⇒Drying ~
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1) 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(2): 1OO parts of 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (10 minutes at 12,000 rpm) and filtered.
(4): Add 300 parts of ion-exchanged water to the filter cake of (3), mix with a TK homomixer (10 minutes at 12,000 rpm), and then filter twice, and filter cake 1 Obtained.

  The above [Filter cake 1] was dried at 45 ° C. for 48 hours with a circulating drier, and sieved with a mesh of 75 μm to obtain [Toner 1]. Subsequently, 100 parts of toner particles were mixed with 0.5 part of hydrophobic silica and 0.5 part of hydrophobic titanium oxide using a Henschel mixer to obtain toner A of the present invention. In this toner A, the occupied area ratio of the wax in the region from the toner surface to 1 μm inside is 15 (%), and the wax present in the vicinity of the toner surface is not present on the toner surface. The number of waxes having a dispersion diameter of 0.5 to 3.0 μm was 55% by number.

[Carrier production example 1]
A magnetite slurry was prepared by putting 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water into a ball mill for 12 hours with respect to 100 parts by weight of magnetite prepared by a wet method. This slurry was spray-granulated using a spray dryer to obtain spherical particles having an average particle diameter of 54 μm. The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles 1.

Mixture for forming a coating layer Silicone resin solution 100 parts by weight Toluene 100 parts by weight γ-aminopropyltrimethoxysilane 6 parts by weight Carbon black 10 parts by weight

  The said mixture was disperse | distributed for 20 minutes with the homomixer, and the coating layer forming liquid 1 was prepared. This coating layer forming liquid was coated on (by the surface of) 1000 parts by weight of the core particles 1 using a fluidized bed type coating apparatus to obtain a silicone resin-coated carrier A. Further, the carrier A and the toner A are combined with a toner density of 4. It was mixed at 0% by weight and used as a two-component developer.

A toner similar to that of Example 1 was obtained except that the wax of Example 1 was changed as follows.
De-free fatty acid type carnauba wax 7 parts At this time, the toner average volume particle size was 6.5 μm, and the content of 5 μm or less was 85%. Further, the chloroform insoluble content of the toner was 0%. Further, the value of the toner surface friction coefficient at this time was 0.28. A ferrite carrier not coated with a resin coat was used as a carrier, mixed with the toner at a concentration of 4.0% by weight, and used as a developer.

A toner was prepared in the same manner as in Example 1 except that the wax used in Example 2 was used and the amount used was changed as follows.
De-free fatty acid type carnauba wax 4.5 parts At this time, the toner average volume particle size was 6.5 μm, and the content of 5 μm or less was 80%. Further, the chloroform insoluble content of the toner was 0%. Further, the value of the friction coefficient at this time was 0.3. A ferrite carrier not coated with a resin coat was used as a carrier, mixed with the toner at a concentration of 4.0% by weight, and used as a developer.

Polyester resin B (chloroform insoluble matter 25%) 20 parts Styrene acrylic resin 80 parts Desorbed fatty acid type carnauba wax 4.5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei) 10 parts Metal salt of salicylic acid derivative 1 part Above composition Was prepared in the same manner as in Example 1 to obtain a toner. The toner average volume particle size at this time was 6.5 μm, and the content of 5 μm or less was 80%. Further, the chloroform insoluble content of the toner was 21%. Further, the value of the toner surface friction coefficient at this time was 0.3. As a carrier, a ferrite carrier not coated with a resin coat was used and mixed with the toner at a concentration of 4.0% by weight and used as a developer.

  The toner was used as a two-component developer in the same manner except that the toner of Example 1 was changed from ester wax to de-free fatty acid carnauba wax and used as toner G. Further, kneading was carried out in the same amount of raw material as in Example 4, and then the pulverization step and classification step were adjusted to obtain a toner base. The obtained toner base was mixed with 0.5 wt% of hydrophobic silica to obtain a final toner. At this time, the toner average volume particle size was 6.5 μm, and the content of 5 μm or less was 65%. Further, the chloroform insoluble content of the toner was 22%. Further, the value of the toner surface friction coefficient at this time was 0.32. As a carrier, a ferrite carrier not coated with a resin coat was used and mixed with the toner at a concentration of 4.0% by weight and used as a developer.

Polyester resin B (chloroform insoluble matter 25%) 100 parts Desorbed fatty acid type carnauba wax 4.5 parts Carbon black (# 44: manufactured by Mitsubishi Kasei) 10 parts Metal salt of salicylic acid derivative 1 part Example of mixture of the above composition The toner was prepared in the same manner as in No. 1. At this time, the toner average volume particle diameter was 6.5 μm, and the content of 5 μm or less was 63%. Further, the chloroform insoluble content of the toner was 21%. Further, the value of the toner surface friction coefficient at this time was 0.32. As a carrier, a ferrite carrier not coated with a resin coat was used and mixed with the toner at a concentration of 4.0% by weight and used as a developer.

The same toner as used in Example 6 was used as the toner, and the carrier and a magnetite particle having an average particle diameter of 50 μm coated with a silicone resin (film thickness: 0.5 μm) were used. Mixed by weight% and used as developer.
[Comparative Example 1]

A toner similar to that of Example 1 was obtained and evaluated except that the wax of Example 1 was changed to the following.
Low molecular weight polypropylene (Biscol 660P: Sanyo Kasei Co., Ltd.) 15 parts

The toner surface friction coefficient at this time was 0.16. At this time, the toner average volume particle size was 6.5 μm, and the content of 5 μm or less was 85%. Further, the chloroform insoluble content of the toner was 0%. The toner surface friction coefficient at this time was 0.18. As a carrier, a ferrite carrier not coated with a resin coat was used and mixed with the toner at a concentration of 4.0% by weight and used as a developer.
[Comparative Example 2]

  In Example 1, evaluation was performed in the same manner as in Example 1 except that the melting temperature at the time of toner kneading by a roll mill was changed to 180 ° C. At this time, the toner average volume particle size was 6.5 μm, and the content of 5 μm or less was 87%. Further, the chloroform insoluble content of the toner was 0%. The toner surface friction coefficient at this time was 0.16. As a carrier, a ferrite carrier not coated with a resin coat was used and mixed with the toner at a concentration of 4.0% by weight and used as a developer.

  In Examples 2 to 4 and Comparative Examples 1 and 2, regarding the dispersion state of the wax in the toner, first, the dispersion diameter can be controlled by changing the stirring conditions of the raw material in the oil phase preparation, and to the vicinity of the toner surface. The dispersion of can be controlled by changing the aging temperature and time in the emulsification step. Two components are produced in the same manner as in Example 1 except that the toners obtained by changing these conditions and arbitrarily changing the ratio of the area occupied by the wax in the region from the toner surface to the inside of 1 μm are changed to toners B to F. Used as a developer.

The evaluation items in Table 1 are as follows.
[Evaluation item]
(Fixability evaluation)
Ricoh type 6200 paper was set in an apparatus in which the fixing unit of the RICOH copier MF-200, which uses a PTFE roller as a fixing roller, was modified, and a copying test was performed. A copy image having an image density of 1.2 with a Macbeth densitometer was obtained, and the copy image with the fixing temperature changed was rubbed 10 times with a clock meter equipped with a sand eraser, and the image density before and after that was measured. The fixing rate was determined using the following formula.
[(Image density after 10 times of sand eraser) / (Previous image density)] × 100 = Fixing rate (%)

A temperature at which a fixing rate of 70% or more is achieved is defined as a minimum fixing temperature. The minimum fixing temperature of conventional low-temperature fixing toner is about 140 to 150 ° C., and this minimum fixing temperature is a measure of low-temperature fixability. The evaluation conditions for low-temperature fixing are a paper feed linear velocity of 120 to 150 mm / sec, a surface pressure of 1.2 kgf / cm ² , a nip width of 3 mm, and a hot offset evaluation condition of a paper feed linear velocity of 50 mm / sec, The surface pressure was set to 2.0 kgf / cm ² and the nip width 4.5 mm.

The cold offset occurrence temperature and the hot offset occurrence temperature were determined as follows.
(Low-temperature fixability): A: Less than 130 ° C., ○: 130-140 ° C., □: 140-150 ° C., Δ: 150-160 ° C., x: 160 ° C. or higher (hot offset property) A: 201 ° C. or higher, ○ : 200 to 191 ° C, □: 190 to 181 ° C, Δ: 180 to 171 ° C, x: 170 ° C or less

(Heat resistant storage stability evaluation)
20g of toner sample is put in a 20ml glass bottle, and the glass bottle is tapped about 50 times to harden the sample tightly, and then left in a constant temperature bath at 50 ° C for 24 hours. I asked for it.
A: Penetrating, B: ~ 25 mm, Δ25-20 mm, X: 20-15 mm, 15 mm or less (filming, image stability, spent rate evaluation)
The paper is set in a Ricoh copier imagio 2730 and a paper passing test is performed to evaluate filming, image stability, and spent rate.

Filming Continuous 100,000 sheets (printing rate 6%) were copied, and after 100,000 sheets, it was confirmed whether filming had occurred on the photoreceptor. At the same time, a halftone image was output and the presence or absence of white bands was also evaluated. The evaluation of filming on the photosensitive member was visually ranked into 5 levels, with the better being ranked 5 and the worse being ranked 1. Further, half-tone white belts were evaluated as “O” when they were not generated, “Δ” when they were generated but at an acceptable level, and “X” when they were generated at the NG level.

-Image stability Continuous 100,000 sheets (printing rate 6%) were copied and the image density, fine line reproducibility and background stain after 100,000 sheets were examined, and these were comprehensively judged.
A: Particularly excellent, B: Excellent, B: Slightly inferior, X: Extremely inferior.

-Spent rate The toner is removed from the developer after the 300,000 copy test by the blow-off method, the remaining carrier weight W1 is put in toluene, the melted material is dissolved, washed, and dried. From the melt weight W2 at that time The spent rate was determined and evaluated.
Spent ratio (wt%) = [(W1-W2) / W1] × 100
A: 0 to 0.02 wt%, O: 0.02 to 0.05 wt%, Δ: 0.05 to 0.08 wt%, x: less than 0.08 wt%

  Although the present invention has been specifically described above based on the preferred embodiments, it is needless to say that the present invention is not limited to the above-described ones and can be variously modified without departing from the gist thereof.

1 is a schematic cross-sectional view of a fixing roller used in an image forming apparatus according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Metal cylinder 5 Heating lamp 6 Metal cylinder 7 Offset prevention layer 8 Heating lamp

Claims (9)

An electrophotographic image using an oilless fixing having a toner containing at least a binder resin, a wax and a colorant and having a surface pressure (roller load / contact area) value of 1.5 × 10 ⁵ Pa or less at the time of fixing. Forming device,
The developer used in the image forming apparatus is composed of a carrier and the toner, and when the toner is observed with a transmission electron microscope, the ratio of the area occupied by the wax in the internal region from the surface of the toner to 1 μm is as follows: An image forming apparatus characterized by being 10 to 40%.   2. The image forming apparatus according to claim 1, wherein among the waxes dispersed in the toner, the dispersed wax existing in the vicinity of the surface of the toner is 70% by number or more of the total wax.   The image forming apparatus according to claim 1, wherein the dispersed wax existing dispersed inside the toner is not substantially exposed on a surface of the toner.   The image according to any one of claims 1 to 3, wherein wax dispersed particles having a dispersed wax diameter of 0.5 to 3 µm in the toner occupy 60% by number or more. Forming equipment.   5. The image forming apparatus according to claim 1, wherein the wax is at least one wax selected from de-free fatty acid carnauba wax, rice wax, and montan wax. 6.   In the toner, a toner material liquid in which a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a release agent is dispersed in an organic solvent is subjected to at least one crosslinking or elongation reaction in an aqueous medium. 6. The image forming apparatus according to claim 5, wherein the toner is a toner obtained by a reaction.   At least one reaction of cross-linking or extension reaction in an aqueous medium is performed on a toner material liquid in which at least a polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant and a release agent are dispersed in an organic solvent. A toner obtained by allowing the toner to be obtained.   The toner according to claim 7, wherein the toner has a spindle shape.   The ratio (r2 / r1) between the major axis r1 and the minor axis r2 of the toner is 0.5 to 0.8, and the ratio (r3 / r2) between the thickness r3 and the minor axis r2 is 0.7 to 1. The toner according to claim 8, wherein the toner is represented by 0.0.

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