JP5041716B2 - Fixing method and image forming method - Google Patents

Description

The present invention relates to an image forming method using the constant Chakuhoho and fixing method.

  A belt-type fixing device using electromagnetic induction heating includes a fixing roller, a counter roller arranged in parallel with the fixing roller, an endless fixing belt wound between the fixing roller and the counter roller, and a fixing belt. An induction coil that heats from the outside and a pressure roller that presses the fixing roller via the fixing belt are provided. Then, the recording paper is passed between the fixing belt and the pressure roller, and at this time, the toner image is fixed on the recording paper by the heat from the fixing belt and the pressing force by the pressure roller (see, for example, Patent Document 1). .

  Generally, the fixing belt has a laminated structure in which a base material, a heat generating layer, an elastic layer, and a release layer are laminated in order from the bottom.

  The substrate is made of an endless belt and is made of a heat resistant resin. As a material of the heat resistant resin, polyimide, polyamideimide, polyetherketone (PEEK) or the like is used. From the rigidity and heat capacity of the fixing belt, the thickness of the substrate 1 is usually set to 20 μm to 100 μm.

  As the heat generating layer, metals such as SUS, iron, nickel, manganese, titanium, chromium and copper are used. The elastic layer is necessary for obtaining image uniformity, and heat resistant rubber such as silicone rubber or fluororubber of about 100 to 300 μm is used. The release layer is made of a fluorine resin or the like having excellent heat resistance and durability because it is in pressure contact with the transfer paper and toner.

  On the other hand, the particle size of the toner is being reduced in order to improve the image quality of the image, and the resolution and sharpness of the image are improved by the particle size reduction. However, there is a problem that the fixing property of the toner is deteriorated in a halftone portion formed of toner having a small particle diameter. This phenomenon is particularly noticeable in high-speed fixing. The reason for this is that the toner “attachment amount” in the halftone portion is small, and the toner transferred to the concave portion of the fixing sheet as the recording medium has a small amount of heat applied from the heating roller, and the convex portion of the fixing sheet. This is because the fixing pressure in the concave portion is suppressed and lowered.

  On the other hand, since the layer thickness of the toner transferred to the convex portion of the fixing sheet in the halftone portion is thin, the shear force applied to each toner particle is larger than that in the solid black portion where the toner layer thickness is thick, and the offset phenomenon. Tends to occur and tends to be a low-quality fixed image. That is, improvement in fixing performance and improvement in hot offset resistance are required.

  In order to achieve both the fixing performance and the anti-hot offset performance, various researches have been conducted up to now, focusing on binder resins. In particular, in order to improve the low-temperature fixing performance in response to energy saving related to environmental problems, a crystalline polyester resin that is quickly eluted has begun to be used.

  Conventionally, a technique for lowering the fixing temperature has been developed using a toner to which a low-melting crystalline compound is added in order to fix at low temperature while maintaining storability, and patent applications have been filed. However, in such a technique, since a large amount of a crystalline compound is added, light scattering due to the crystalline compound occurs, and the transparency of the finished image is poor.

In addition, there is an attempt to add a specific non-olefinic crystalline polymer having a sharp melt property at a glass transition temperature in a binder for the purpose of improving low-temperature fixability (see, for example, Patent Document 2). It cannot be said that the molecular weight is optimized. Similarly, there is an attempt to use a crystalline polyester having sharp melt properties (see, for example, Patent Documents 3 and 4). However, in Patent Document 3, the acid value and hydroxyl value of the crystalline polyester toner are 5 or less and 20 or less, respectively. However, since the affinity between paper and crystalline polyester is low, sufficient low-temperature fixability cannot be obtained. In addition, the molecular structure and molecular weight of the crystalline polyester are not optimized, and the microdomain structure in the toner for exhibiting the sharp melt property of the crystalline polyester is not disclosed, so that sufficient low-temperature fixability is achieved. Cannot be obtained. Patent Document 4 does not disclose a microdomain structure in the toner for exhibiting the sharp melt property of the crystalline polyester, so that sufficient low-temperature fixability cannot be obtained. Therefore, even if these conventionally known technologies are applied, it is impossible to achieve the specifications of the DSM (Demand-side Management) program, and it is necessary to establish a low-temperature fixing technology that is further advanced than the conventional technical field. . For further low-temperature fixing, it is necessary to control the thermal characteristics of the resin itself. However, if the glass transition temperature (Tg) is lowered too much, the heat-resistant storage stability deteriorates and the molecular weight is reduced to soften the resin. If the temperature is lowered too much, there is a problem that the temperature at which hot offset occurs is lowered. For this reason, by controlling the thermal characteristics of the resin itself, it has not been possible to obtain a toner having excellent low-temperature fixability and a high hot offset occurrence temperature.
JP 11-329700 A JP 62-63940 A Japanese Patent No. 2931899 JP 2001-222138 A US Pat. No. 2,297,691 Japanese Patent Publication No.49-23910 Japanese Patent Publication No.43-24748 JP 60-90344 A JP-A 64-15755 Japanese Patent Laid-Open No. 2-82267 JP-A-3-229264 JP-A-3-41470 JP-A-11-305486

  However, in the conventional fixing device and toner, since the fixing belt is heated only by the induction coil and the temperature of the fixing belt is not controlled, hot offset tends to occur at both ends of the belt. Further, in order to greatly reduce the low-temperature fixability and sufficiently secure the hot offset, further low-temperature fix has not been promoted because of the contradictory relationship between the low-temperature fixability and the hot offset and the storage stability.

  Also, in the conventional fixing device, the end of the opposing roller has a bearing and has a large heat capacity, so when the fixing belt starts to be heated by the induction coil, the heat escapes to the opposite roller end, There is also a problem that the temperature rise at the end of the roller is slower than the temperature rise at the central portion of the opposing roller, and as a result, the time until the fixing device becomes ready for use, that is, the rise time becomes longer.

Accordingly, a first object of the present invention is to provide a constant Chakuhoho and image forming method for significant energy savings without hot offset occurs in the belt side edge portions.

A second object of the present invention, while preventing the wasteful consumption of energy can be satisfactorily fixed immediately after the power is turned on, the constant wear was feasible even better low-temperature fixability at low power capacity A method and an image forming method are provided.

Furthermore, a third object of the present invention, the low speed up to the high-speed image forming apparatus, no fog, constant Chakuhoho and image the image density is high and you allow resolution superior high-definition image formation It is to provide a forming method .

According to one aspect of the present invention, by using the fixing device, a method of fixing a toner to a recording medium, the fixing device includes a coil portion for generating a magnetic flux, and that the magnetic shunt alloy to heat by the magnetic flux A fixing belt , and the fixing belt is formed by sequentially laminating a base material, an elastic layer, and a release layer, and the magnetic shunt alloy is on the side where the base material is provided with respect to the elastic layer. The toner includes a crystalline polyester and a release agent, and has a ratio of a weight average particle diameter to a number average particle diameter of 1.00 to 1.20, and a particle diameter of 2 μm or less. The content of is 12% by number or less .

According to the invention described in claim 1, the low temperature fixability becomes excellent, high quality image can be obtained.
Invention according to claim 2, in the fixing method according to claim 1, before Symbol toner chromatography is 5 to 20% content of the crystalline polyester, the content of the release agent is 2 to 5% , and the release agent has a melting point of 60 to 90 ° C.
According to the second aspect of the present invention, the low-temperature fixability is good and a high-quality image can be obtained .
According to a third aspect of the invention, in the fixing method according to the first or second aspect, the toner further contains a urea-modified polyester and an unmodified polyester.
According to the invention described in claim 3, high releasability, low-temperature fixability and high-quality images can be obtained.

Invention according to claim 4, in the fixing method according to any one of claims 1 to 3, the toner, along with further contain a colorant, a resin fine particles on the surface, before Symbol resin particles Has a glass transition point of 50 to 90 ° C.

According to the fourth aspect of the present invention, the crystalline polyester, which is a low softening resin, is covered with resin fine particles on the surface, and it melts at the time of fixing, and the crystalline polyester inside oozes out to achieve further low-temperature fixability. The

The invention according to claim 5, in the fixing method according to any one of claims 1 to 4, wherein the toner is characterized in that the weight average particle diameter of Ru 3.0 to 6.0μm der .

According to the invention described in 請 Motomeko 5, high have releasing property, low-temperature fixability, high-quality image can be obtained.

Invention according to claim 6, characterized in that the fixing method according to any one of claims 1 to 5, wherein the toner content of the particle size 8μm or more of the particles is less than 2 vol% And

According to the invention of claim 6, abnormal images with high releasability without the occurrence of, an image of the low-temperature fixability and high image quality is obtained.

Invention according to claim 7, characterized in that the fixing method according to any one of claims 1 to 6, wherein the toner has a particle size of the content of particles smaller than 3μm is 5 vol% or less And

According to the invention described in claim 7, high have releasability, images low temperature fixability and high-definition image quality can be obtained.

The invention described in 請 Motomeko 8, in the fixing method according to any one of claims 1 to 7, wherein the toner is characterized by a polymerized toner.

According to a ninth aspect of the present invention, the image forming method includes a step of fixing toner onto a recording medium using the fixing method according to any one of the first to eighth aspects .

According to the ninth aspect of the invention, high releasability, low temperature fixability and high quality images can be obtained.

According to the onset bright, no contamination due dissolves from the fixing cleaning roller, also low-temperature fixability, hot offset resistance, heat resistant storage stability, good flow properties, excellent image resolution and image density can be obtained .

  The present invention is described in detail below.

  In the electromagnetic induction heating type heating device of the present invention, at least a part of the magnetic core is made of a magnetic shunt alloy whose saturation magnetic flux density decreases when the temperature exceeds the desired control temperature (Tc), so that the temperature of the induction heat generating member is increased. As the temperature rises, the temperature of the magnetic shunt alloy part constituting a part of the magnetic core also rises, and as a result, the saturation magnetic flux density of the magnetic shunt alloy part decreases, so the amount of magnetic flux passing through the magnetic core decreases, The eddy current generated in the induction exothermic member that is the secondary coil is also reduced, and the temperature rise of the induction exothermic member is stopped, and conversely, the temperature of the induction exothermic member is lowered, resulting in the temperature of the magnetic shunt alloy When the temperature falls below the predetermined temperature Tc, the saturation magnetic flux density of the magnetic shunt alloy increases, so that the magnetic flux passing through the magnetic core increases. As a result, the eddy current in the induction heat generating member increases and the temperature rises. In this way, the temperature control circuit based on the temperature detection signal and the temperature sensor are not required, and the heat generation temperature of the induction heat generating member can be controlled.

  Hereinafter, an induction heating apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a fixing device 10 according to a first embodiment of the present invention. The heating device will be described with reference to this figure. As shown in the figure, the fixing device 10 includes a fixing roller 11, a counter roller (heating roller) 12 that is arranged in parallel with the fixing roller 11 and is made of a nonmagnetic material, and a fixing roller 11 and a counter roller 12. An endless fixing belt 13 wound around and having a magnetic material inside, an induction coil (induction heating means) 14 disposed on the side of the opposing roller 12 for electromagnetic induction heating, and a fixing belt 13 And a pressure roller 16 that presses the fixing roller 11 and forms a nip portion 15 on the fixing belt 13.

  The fixing roller 11 has a heat insulating layer on the outside of a metal core such as aluminum or iron, and has an outer diameter set to 40 mm, for example. Since the heat insulation layer needs heat resistance, silicone rubber (including sponge) is used. The lower the thermal conductivity of the material used for the heat insulating layer, the more effective it is, and it is generally preferable to be 0.2 W / m / K or less. The counter roller 12 is formed of aluminum, SUS, or the like whose core metal is a nonmagnetic material.

  In the pressure roller 16, a heat-resistant elastic layer such as silicone rubber is formed on the outer periphery of the core metal, and a surface release layer made of fluorine resin or the like is formed on the outer periphery of the heat-resistant elastic layer. Further, the surface hardness of the pressure roller 16 is formed to be higher than the surface hardness of the fixing roller 11 in order to improve the separation of the recording paper P from the fixing belt 13. Therefore, when the fixing roller 11 is pressed by the pressure roller 16 via the fixing belt 13, a part of the fixing belt 13 is deformed in a convex shape toward the fixing roller 11, and a nip portion 15 is formed in the fixing belt 11. . The thickness of the heat resistant elastic layer of the pressure roller 16 is about 1 mm to several mm.

  The induction coil 14 is wound around an exciting core 17 made of ferrite or permalloy and having a substantially concave cross section. When a high frequency current of several kHz to several hundred kHz is passed through the induction coil 14, an induction current is generated in the fixing belt 13. Due to this induced current, the fixing belt 13 generates heat locally in the vicinity of the induction coil 14 and rapidly rises in temperature.

  Further, a temperature sensor 18 for detecting the temperature of the fixing belt 13 heated by electromagnetic induction, and a control device 19 for taking in a detection signal from the temperature sensor 18 and controlling a high-frequency current flowing through the induction coil 14 are provided. Yes.

  Further, a guide plate 20 that conveys the recording paper P to the fixing device 10 is provided below the facing roller 12. Unfixed toner T adheres to the surface of the recording paper P.

  FIG. 2 is a longitudinal sectional view of the fixing belt 13. As shown in FIG. 2, the fixing belt 13 has a laminated structure in which a base material 13a, an elastic layer 13b, and a release layer 13c are laminated in order from the lower side.

  The substrate 13a is formed of an endless belt, and a magnetic shunt alloy powder is blended in the resin based on a heat resistant resin. As the material of the heat-resistant resin as a base, polyimide, polyamideimide, polyetherketone (PEEK), or the like can be used. In addition, the thickness of the base material 13a is desirably 20 μm to 100 μm from the rigidity and heat capacity of the belt.

  The elastic layer 13b is necessary for obtaining image uniformity, and heat-resistant rubber such as silicone rubber or fluororubber of about 100 to 300 μm is used.

  The release layer 13c is in pressure contact with the recording paper P and the toner T. For this reason, as the release layer 13c, a fluorine resin or the like excellent in heat resistance and durability is preferable.

3 mainly includes a fixing roller 31 (fixing member) as a heat generating member, a pressure roller 30, an induction heating unit 24, and the like. The heat generating layer 22b of the fixing roller 31 is made of a magnetic shunt alloy having a heat generating layer formed so that the Curie point is equal to or higher than the fixable temperature and the adjusted Curie point is set so as not to cause hot offset during fixing. Moreover, the induction heating part 24 is comprised by the coil part 25 formed in loop shape. The coil portion 25 is disposed so as to sandwich the front and back surfaces of the fixing roller 31. When an alternating current of 10 k to 1 MHz is supplied to the coil unit 25, magnetic lines of force are supplied into the loop of the coil unit and heated by the fixing roller 31 by electromagnetic induction. When the temperature of the heat generating layer 22b of the fixing roller 31 exceeds the Curie point, the heat generation of the heat generating layer 22b is efficiently limited.

  Referring to FIG. 4, the coil portion 25 is disposed so as to face the front and back surfaces of the support roll 23.

  Next, toner used in the fixing device will be described.

  As a result of intensive studies, the inventors of the present invention preferably use a crystalline polyester resin and an amorphous resin as a binder resin for the toner composition when forming an image using a toner having a reduced particle size obtained by polymerization. The present invention finds that the above-mentioned problems can be solved by adjusting the content and the like according to the compatibility and the viscosity of the solution, and adjusting the selection of the release agent and its dispersion state or content. It came to.

  Hereinafter, the present invention will be specifically described.

  That is, the present invention includes a fixing roller, a counter roller made of a nonmagnetic material and arranged in parallel with the fixing roller, an endless fixing belt wound between the fixing roller and the counter roller, An induction heating unit that electromagnetically heats the fixing belt; and a pressure roller that presses the fixing roller via the fixing belt; and a recording sheet is passed between the fixing belt and the pressure roller. A fixing device for fixing unfixed toner on the recording paper, wherein the fixing belt has a laminated structure in which a base material, an elastic layer, and a release layer are laminated in order from the bottom, and the base material is a magnetic shunt. The alloy is formed of a dispersed material, and the Curie temperature of the magnetic shunt alloy is set lower than the hot offset temperature of the toner, and the toner used is a crystalline polyester having a DSC Tg of 40 ° C. to 95 ° C. 20% included Characterized in that by and containing 2-5% of a wax having a melting point 60 to 90 ° C. is releasing agent.

  The toner is an image forming toner used for image formation of a fixing device, and includes at least a colorant, a release agent, a crystalline polyester resin, and an amorphous polyester binder resin as a component of the toner. The crystalline polyester comprises a THF-soluble component having a glass transition point (Tg) of 40 to 95 ° C., and the non-crystalline polyester has a glass transition point (Tg) of 35 ° C. to 60 ° C. and the ratio thereof is a crystalline polyester. The content ratio of the toner is 10 to 30% of the whole resin, preferably 15 to 25%, and the toner particle surface needs to be coated with 1.0 to 3.5% of organic fine particles on the particle surface. By adopting this toner particle structure, the low-temperature fixing exhibited a further effect in the fixing device using the induction heating and the magnetic shunt alloy.

In other words, in the conventional fixing device that does not use induction heating and a magnetic shunt alloy, the above toner cannot exhibit an effect in an energy-saving fixing device that suppresses power consumption due to a trade-off between hot offset, low-temperature fixing, and heat-resistant storage stability. It was. In the case of a pulverized toner having a relatively uniform toner particle composition, if the Tg of the binder resin is lowered too much, the low-temperature fixing property is improved, but the hot offset property and the heat-resistant storage property are lowered. The suspension polymerization toner and the emulsion aggregation toner have the same tendency, and the low temperature fixing property, the hot offset property, and the heat resistant storage property are in a trade-off relationship. Recently, Japanese Patent Application Laid-Open Nos. 11-149180 and 2000-292981 have filed patents in which resin fine particles are fixed on the surface of toner particles. The particle structure has the effect of preventing bleeding of the low softening binder and is effective against hot offset compared to conventional toners. However, if the amount of resin fine particles fixed is large, the hot offset property is improved. On the other hand, the low-temperature fixability needs to be balanced because the fixed resin particles cause a fixing inhibition and decrease. But the low-temperature fixability binder resin exudes Lowering the Tg to 40 ° C. or less of the good of Suruga hot offset tends to occur. Especially for the hot offset generation temperature, the accuracy of the heater temperature control range is related to the hot offset generation temperature, and the margin of the hot offset generation temperature decreases due to the heater temperature overshoot, so the conventional fixing machine and toner were used. Therefore, it is difficult to improve the fixing width.
(Crystalline polyester)
The crystalline polyester contains a diol compound having 2 to 6 carbon atoms, particularly 1,4-butanediol, 1,6-hexanediol and derivatives thereof as an alcohol component of 80 mol% or more, preferably 85 to 100 mol%. And a crystal having a structure represented by the following general formula (1) synthesized using fumaric acid or a carboxylic acid having a double bond (C = C bond) as an acidic component, and derivatives thereof A preferred polyester resin is preferred.
_{[- O -CO- (CR 1 =} CR 2) L -CO-O- (CH 2) n -] m (1)
(Here, n and m are the number of repeating units. L is an integer of ₁ to _3. R ₁ and R ₂ are hydrogen atoms or hydrocarbon groups, which may be the same or different.)
Further, as a method for controlling the crystallinity and softening point of the crystalline polyester resin, a trivalent or higher polyhydric alcohol such as glycerin as an alcohol component and a trivalent or higher polyvalent such as trimellitic anhydride as an acid component can be used during polyester synthesis. Examples thereof include a method of designing and using a non-linear polyester subjected to condensation polymerization by adding a polyvalent carboxylic acid.

  The molecular structure of the crystalline polyester of the present invention can be confirmed by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. in addition to NMR measurement by solution or solid. As an example, those having absorption at 965 ± 10 cm −1 or 990 ± 10 cm −1 based on δCH (out-of-plane variable angular vibration) of olefins can be given.

  As for the molecular weight, from the viewpoint that the above-mentioned molecular weight distribution is sharp and the low molecular weight is excellent in low-temperature fixability, as a result of intensive studies, the molecular weight distribution by GPC of the soluble part of o-dichlorobenzene is indicated by the log ( M), the peak position of the molecular weight distribution diagram in which the vertical axis is expressed in weight% is in the range of 3.5 to 4.0, the half width of the peak is 1.5 or less, and the weight average molecular weight (Mw) is 1000. -30000, number average molecular weight (Mn) of 500 to 6000, and Mw / Mn of 2 to 8 are preferable.

The melting temperature and F1 _{/ 2} temperature are desirably low as long as the heat resistant storage stability is not deteriorated, and the DSC endothermic peak temperature is preferably 40 to 95 ° C. If it is less than 40 ° C, the hot offset is lowered, and if it exceeds 95 ° C, the fixing property is lowered. In addition, the crystalline polyester has an appropriate content in the binder from the viewpoint of compatibility with the non-crystalline polyester and the urea-modified polyester resin, and from the viewpoint of toner fixability and developability, and the total content of the binder component is 5 to 20%. Preferably, it is 10 to 20%. If it is less than 5%, the effect on the fixing property is small, and if it exceeds 20%, the dispersibility is lowered and emulsification becomes difficult. In addition, the charging property of the toner becomes an unstable system.

  The acid value of the crystalline polyester is 5 mg KOH / g or more, more preferably 10 mg KOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between paper and resin. On the other hand, in order to improve the hot offset property, it is preferably 45 mg KOH / g or less. Further, the hydroxyl value of the crystalline polymer is preferably 0 to 50 mgKOH / g, more preferably 5 to 50 mgKOH / g in order to achieve a predetermined low-temperature fixability and good charging characteristics. .

(Effect of crystalline polyester)
Since the crystalline polyester resin in the toner of the present invention has crystallinity, it exhibits a heat-melting characteristic that shows a sudden decrease in viscosity near the fixing start temperature. In other words, the heat-resistant storage stability due to crystallinity is good until just before the melting start temperature, and at the melting start temperature, a sharp viscosity drop (sharp melt property) is caused and fixing is performed. Toner can be designed. In addition, a wax having a melting point within the range of 60 to 90 ° C. added at the same time to cause a decrease in viscosity is faster to dissolve than when there is no crystalline polyester, and has a great release effect. This is the reason why the low-temperature fixability can be improved without degrading the releasability due to the synergistic effect with the so-called crystalline polyester. Another significant improvement in the fixing width is that the hot offset property is improved by using a magnetic shunt alloy. Conventionally, in order to improve the low-temperature fixability, attempts have been made to improve the low-temperature fixability by lowering the viscosity of the binder, lowering the viscoelasticity, or lowering the melting point or lowering the molecular weight of the wax. This is because the accuracy of the fixing temperature control of the machine is not enough, that is, the toner overshoots when the fixing heater is overheated, so the toner needs to have sufficient releasability, so the low-temperature fixing ability cannot be fully demonstrated. This is why.

(Organic solvent)
Organic solvents that dissolve crystalline polyester completely at high temperature to form a transparent uniform solution, but on the other hand, those that phase separate from crystalline polyester when cooled to low temperature and form an opaque heterogeneous solution are used. Is done. In detail, the melting temperature (Tm) of the crystalline polyester is used as a reference so long as it exhibits non-solvent characteristics at a temperature lower than (Tm-40) ° C., and exhibits good solvent characteristics at higher temperatures. As specific examples, toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more.

Organic fine particles (resin fine particles)
The resin fine particles used in the present invention have a glass transition point (Tg) of 50 to 90 ° C. When the glass transition point (Tg) is less than 50 ° C., the toner storage stability is deteriorated. Blocking occurs during storage and in the developing machine. When the glass transition point (Tg) is higher than 90 ° C., the resin fine particles inhibit the adhesiveness with the fixing paper, and the minimum fixing temperature is increased. A more preferred range is 50 to 70 ° C.

  The weight average molecular weight is desirably 100,000 or less. Preferably it is 50,000 or less. The lower limit is usually 4000. When the weight average molecular weight exceeds 100,000, the resin fine particles inhibit the adhesiveness to the fixing paper, and the minimum fixing temperature increases.

  The resin fine particles may be any resin as long as it can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resins, polyurethane resins, epoxy resins, polyester resins, polyamide resins, polyimides Examples thereof include resins, silicon-based resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. As the resin fine particles, two or more of the above resins may be used in combination. Among these, those made of a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, or a combination resin thereof are preferable because an aqueous dispersion of fine spherical resin particles is easily obtained.

  The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like.

  In the resin fine particles, the average particle diameter is 5 to 200 nm, preferably 20 to 300 nm.

(Coating amount of resin fine particles)
The resin fine particles in the toner of the present invention are added in the production process in order to control (align) the toner shape (circularity, particle size distribution, etc.), but the glass transition point (Tg) of the resin fine particles unevenly distributed on the toner surface. ) Is 50 to 90 ° C., and the coating amount on the toner particles is important to be 1.0% or more. When the coating amount is 3.5% or more of the total toner weight, the inner binder resin is difficult to be dissolved under the influence of the particle outer shell, and as a result, the fixing property is lowered. If it is 1% or less, it is difficult to emulsify. When the glass transition point (Tg) is less than 50 ° C., the toner storage stability deteriorates, and blocking occurs during storage and in the developing machine. When the glass transition point (Tg) is 90 ° C. or higher, the resin fine particles inhibit the adhesion of the toner to the fixing paper, and the minimum fixing temperature increases. Accordingly, since a sufficient fixing temperature range cannot be secured, there is a problem that fixing cannot be performed by a copying machine of a low-temperature fixing system, or the fixed image is peeled off when rubbed. The resin fine particles of the present invention have a function of improving the triboelectric chargeability of the toner. Therefore, if the coating amount is less than 1.0%, sufficient triboelectric charging characteristics cannot be imparted to the toner, so that a sufficient image density cannot be obtained or background stains occur.

  The coating amount of the resin fine particles is calculated by quantifying the monomer component of the organic fine particles using a pyrolysis gas chromatograph. Measurement conditions will be described later.

  Based on the above investigation results, the present inventors have balanced the low-temperature fixing, heat-resistant storage stability, hot-offset resistance, (fluidity), etc., which is the object of the present invention, while utilizing the toner composition having a low-temperature core-shell structure. A toner that can be achieved well and can form a high-definition image has been realized.

  That is, in the present invention, the photosensitive member was charged while being transferred, the latent image forming step, the developing step using toner, the transfer step, the cleaning step, and the recording medium transferred while being conveyed between the heating member and the pressure member. The above-mentioned object is achieved by suitably selecting and adjusting the composition of the toner used in the developing process of the image forming process composed of the process of fixing the toner image, and reducing the particle size by polymerization. Specifically, the toner to be used contains a crystalline polyester resin and an amorphous polyester resin as at least a colorant, a release agent, and a binder resin.

  As will be described later, the binder resin suitably used in the present invention is a urethane-modified polyester resin formed by a polyaddition reaction between a compound having an active hydrogen group and a (polyester) prepolymer having an isocyanate group at the terminal ( Abbreviated as a modified polyester resin), which is a blend of a crystalline polyester resin and an amorphous polyester resin.

[Measurement method of glass transition point (Tg)]
The glass transition point (Tg) is measured by the following measuring method.
Apparatus: A TG-DSC system TAS-100 manufactured by Rigaku Corporation is used.
Method: First, about 10 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. Next, after heating from room temperature to 150 ° C. at a heating rate of 10 ° C./min, the sample is allowed to stand at 150 ° C. for 10 minutes, and then the sample is cooled to room temperature and left for 10 minutes. Further, the DSC measurement is performed by heating again to 150 ° C. at a heating rate of 10 ° C./min under a nitrogen atmosphere. Tg is calculated from the contact point between the tangent line and the base line of the endothermic curve near Tg, using the analysis system in the TAS-100 system.

  In the present invention, the toner has a weight average particle diameter (Dv) of 3.0 to 6.0 μm and a ratio (Dv / Dn) to the number average particle diameter (Dn) of 1.00 ≦ Dv / Dn. By satisfying ≦ 1.20, it is possible to obtain a toner that can cope with high resolution and high image quality. Further, by using such a particle size, it is possible to obtain a toner excellent in all of heat-resistant storage stability, low-temperature fixability, and hot offset resistance.

  Conventionally, this has been achieved by lowering Tg in order to ensure low-temperature fixability in particular, but there is a limit to lowering Tg because of the relationship with storage stability. In order to solve this problem, the low-temperature fixability was improved by reducing the particle size. The grounds are as follows.

  By reducing the particle size, it is considered that the toner particle packing property of the unfixed image portion is improved, the thermal conductivity when the fixing heater is heated during fixing is improved, and the toner has excellent low-temperature fixability. . That is, by making the particle size small, further low-temperature fixing can be achieved. On the other hand, when a large amount of toner particles of 8 μm or more are contained, not only fixing inhibition occurs due to a decrease in thermal conductivity of the coarse particles, but also the charge amount distribution of the particles becomes wide in the image area, thereby causing development variation and transfer variation. Occurs to cause variations in image density and a decrease in gradation.

  Next, particles of 3 μm or less measured by the Coulter method and particles of 2 μm or less measured by the flow type particle image measuring device will be described. The Coulter method and flow-type particle image measurement (similar to the circularity measurement method) will be described later.

  In the two-component developer, the balance of the toner is carried out in the developing device of the copying apparatus for a long time. In this balance, the fluctuation of the toner particle diameter in the developer is small, and even in the long-term stirring in the developing apparatus. Good and stable developability is desired. In general, it is said that the smaller the toner particle size, the more advantageous it is to obtain a high-resolution and high-quality image. On the other hand, a toner having a small particle diameter is disadvantageous with respect to transferability and blade cleaning properties.

  The reason for this is that, in the case of a toner having a small particle diameter, the adhesion is increased by increasing the chargeability and the specific surface area of the toner particles, and the adhesion to the carrier and adhesion to the photoconductor are increased. Then, the toner is fused to the surface of the carrier during a long period of stirring in the developing device, thereby causing a problem of reducing the charging ability of the carrier.

  With regard to blade cleaning properties, toner with a smaller particle size is less likely to be scraped, and untransferred toner on the photoconductor tends to cause soiling. These phenomena are greatly related to the particle size distribution of around 3 μm. In particular, as the number of particles of 3 μm or less increases, the transferability and blade cleaning properties decrease. The phenomenon that the untransferred toner increases increases. This phenomenon hinders charging stability at a high level.

  In order to maintain high image quality and long-term cleaning and durability, it is necessary to suppress the toner shape and the content of particles of 2 μm or less measured by a flow type particle image analyzer.

  In particular, long-term stirring of the toner and the carrier in the developing device causes the toner to be fused to the surface of the carrier, thereby reducing the charging ability of the carrier and causing the toner to be fused to a member such as a blade. In addition, untransferred toner remains on the photoconductor, leading to the occurrence of background smudges on the image. In order to prevent this, it has become clear that it is effective that the number-based circle equivalent diameter measured by a flow type particle image analyzer is less than 15% by number of particles having a diameter less than 2.0 μm.

  The average particle size and particle size distribution of the toner were measured by a Coulter counter method. That is, as a particle size distribution measuring device for toner particles, there are Coulter Counter TA-II and Coulter Multisizer IIe (both manufactured by Coulter, Inc.). In the present invention, Coulter Counter TA-II type is used. In addition, an interface (Nichiken Giken) that outputs number distribution and volume distribution and a PC 9801 personal computer (manufactured by NEC) are connected and measured. The specific measurement method is as follows.

[Measurement method by Coulter method]
First, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. The electrolytic solution used here is prepared in a 1% NaCl aqueous solution using primary sodium chloride. As such an electrolytic solution, for example, ISOTON-II (manufactured by Coulter) can be used.

  After adding a surfactant to the electrolytic aqueous solution, 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. By measuring the volume and number of toner particles or toner with this measuring apparatus using a 100 μm aperture, the volume distribution and the number distribution are calculated.

  The channel in the above measurement is as follows: 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to 6.35 μm Less than 6.35 to less than 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Use less than ˜25.40 μm; 25.40 to less than 32.00 μm; 13 channels less than 32.00 to 40.30 μm. That is, particles having a particle size of 2.00 μm or more and less than 40.30 μm are targeted. Thus, the volume-based weight average particle diameter (Dv) obtained from the volume distribution and the number average particle diameter (Dn) obtained from the number distribution are obtained. Then, a ratio Dv / Dn between the volume-based weight average particle diameter (Dv) and the number average particle diameter (Dn) is obtained.

  The average circularity of the toner in the present invention is 0.900 to 0.960, and it is important to have a specific shape (spindle shape) and a distribution in the shape.

  With the irregular shape toner of the present invention having an average circularity of less than 0.900, satisfactory transferability and high-quality images without dust cannot be obtained. The irregularly shaped particles have many points of contact with a smooth medium such as a photoconductor, and the electric charge concentrates on the tip of the protrusion, so that the van der Waals force and the mirror image force are higher than those of a relatively spherical particle. For this reason, in the electrostatic transfer process, the spherical particles are selectively moved in the toner in which the amorphous particles and the spherical particles are mixed, and the character portion and the line portion image are lost. In addition, the remaining toner must be removed for the next development process, and there is a problem that a cleaner device is necessary or the toner yield, that is, the ratio of toner used for image formation is low. Arise. Generally, the average circularity of pulverized toner is usually 0.910 to 0.920 when measured with a flow particle image analyzer.

  As a shape measuring method, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. The circularity is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particle. That is, this value is measured by a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation) and obtained as an average circularity. The specific measurement method is as follows.

[Measurement method of toner shape and distribution by flow type particle image analyzer]
As a specific measuring method, 100 to 150 ml of water from which impure solids have been previously removed is placed in a container, and a surfactant, preferably alkylbenzene sulfonate, is added as a dispersing agent to the container. Further, about 0.1 to 0.5 g of a sample to be measured is added. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the concentration and dispersion of the dispersion are set to 3000 to 10,000 / μl, and the shape and distribution of the toner are measured with the apparatus.

  By the above method, the above-described measurement of fine particles of 2 μm or less can also be performed. That is, the measurement method is the same, and the measurement results of circularity and particle size distribution can be obtained simultaneously. As described above, the particle size analysis is performed using information on the projected area and the perimeter of each particle image obtained by image analysis of the particle image. In the analysis, a circle having the same area as the projected area of the particle image is determined, the diameter of the circle is calculated, the frequency distribution of the particles is calculated based on the result, and the number average based on the number basis and the volume basis The value of the diameter and the volume average diameter are calculated respectively. About 2 micrometers or less, the value which calculated the number% from 0.6 micrometer-2 micrometers is shown.

  The toner used in the present invention includes, for example, a crystalline polyester resin which is at least soluble or dispersed in an organic solvent and has a glass transition point of 35 to 60 ° C., and an amorphous polyester having a glass transition point of 35 to 60 ° C. A dissolved or dispersed product obtained by dissolving or dispersing a compound having an active hydrogen group, which is a composition of a resin and a binder resin, a prepolymer capable of polyaddition with the compound, and a colorant and a release agent; By separately dispersing resin fine particles in water and dispersing in an aqueous medium, and subjecting the compound and the prepolymer to a polyaddition reaction in the dispersion, the organic solvent in the dispersion is removed and granulated. can get.

  Here, the compound having an active hydrogen group is an amine, the prepolymer capable of polyaddition reaction with the compound having an active hydrogen group is a polyester prepolymer having an isocyanate group at the terminal, and the binder resin is a urethane bond. A modified polyester resin that is modified and an amorphous binder resin that is not modified with a urethane bond is also preferably used.

  By combining two resin components composed of such an unmodified polyester resin and a modified polyester resin, a toner particle structure having a low-temperature core-shell structure and a pseudo capsule shape can be formed. Can be achieved.

  Hereinafter, a urethane-modified polyester resin (modified polyester resin) suitable as a binder resin and a non-urethane-modified polyester resin (unmodified polyester resin) suitable as a binder resin for crystalline polyester will be mainly described.

  FIG. 5 shows a schematic diagram of the toner particle structure.

  In order to obtain the toner particle structure shown in FIG. 5, it is necessary to control the range of Tg and molecular weight of the unmodified polyester resin used. That is, it is important to use a non-modified polyester resin contained in the inside of the particle having a Tg of 30 ° C. to 46 ° C. and a molecular weight of 2000 to 10,000 in terms of number average molecular weight. As described above, the toner particles are composed of a low softening point resin, and the modified polyester resin is dispersed to give the particles elasticity so that the toner has a low-temperature core-shell structure and a pseudo capsule shape. A particle structure can be formed.

  Hereinafter, a urethane-modified polyester resin (modified polyester resin) as a second binder resin formed by polyaddition reaction between a compound having an active hydrogen group and a polyester prepolymer having an isocyanate group at the end will be described.

  A specific method for producing the modified polyester resin includes a reaction between a polyester prepolymer (A) having an isocyanate group at the terminal and an amine (B).

  As the polyester prepolymer (A) having an isocyanate group at the terminal, a polyester having an active hydrogen group, which is a polycondensate of polyol (PO) and polycarboxylic acid (PC), was further reacted with polyisocyanate (PIC). Things. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

  Examples of the polyol (PO) include a diol (DIO) and a trivalent or higher polyol (PO), and (DIO) alone or a mixture of (DIO) and a small amount of (TO) is preferable. Diols (DIO) include alkylene glycols (for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycols (for example, , Diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (eg, 1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols ( For example, bisphenol A, bisphenol F, bisphenol S and the like; alkylene oxides of the above alicyclic diols (for example, ethylene oxide, propylene oxide, Chi alkylene oxide, etc.) adducts, alkylene oxide of the bisphenols (e.g., ethylene oxide, propylene oxide, and the like butylene oxide, etc.) adducts. Among these, 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. Examples of the trivalent or higher polyol (PO) include 3 to 8 or higher polyhydric aliphatic alcohols (for example, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); (For example, trisphenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or higher polyphenols and the like.

  Examples of the polycarboxylic acid (PC) include dicarboxylic acid (DIC) and trivalent or higher polycarboxylic acid (PC). (DIC) alone and a mixture of (DIC) and a small amount of (PC) are preferable. Dicarboxylic acids (DIC) include alkylene dicarboxylic acids (eg, succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (eg, maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (eg, phthalic acid, isophthalic acid, etc.) Acid, terephthalic acid, naphthalenedicarboxylic acid, etc.). Among 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 polycarboxylic acid (PC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (for example, trimellitic acid and pyromellitic acid). In addition, as polycarboxylic acid (PC), you may make it react with a polyol (PO) using the acid anhydride of the above-mentioned thing, or lower alkyl ester (for example, methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyol (PO) and the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably 1 as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 5/1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Polyisocyanates (PIC) include aliphatic polyisocyanates (eg, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate); alicyclic polyisocyanates (eg, isophorone diisocyanate, cyclohexyl). Aromatic diisocyanates (eg, tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (eg, α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; Polyisocyanates blocked with phenol derivatives, oximes, caprolactams, etc .; and combinations of two or more of these.

  The ratio of the polyisocyanate (PIC) is usually 5/1 to 1/1, preferably 4 /, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5/1, the low-temperature fixability deteriorates. When the equivalent ratio [NCO] / [OH] is less than 1/1, the urea content in the modified polyester becomes low when polyaddition reaction is performed with the amines (B) described later to form a urethane-modified polyester, and hot resistance is reduced. Offset property deteriorates.

  The content of polyisocyanate (PIC) in the polyester prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt% in the constituent components. It is. 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 (at the end) is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1. 8 to 2.5. If it is less than 1 per molecule, the molecular weight of the modified polyester resin formed will be low, and the 1/2 outflow temperature after lab plast milling will decrease.

  As amines (B), diamine (B1), triamine or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and amino groups of (B1) to (B5) (B6) etc. that are blocked.

  Examples of the diamine (B1) include aromatic diamines (eg, phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane); alicyclic diamines (eg, 4,4′-diamino-3,3′dimethyldicyclohexyl). Methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (eg, ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like.

  Examples of the trivalent or higher polyamine (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.

  (B6) obtained by blocking the amino group of (B1) to (B5) (K6) obtained from the amines of (B1) to (B5) and ketones (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) Compounds, oxazoline compounds and the like. Among the amines (B), preferred are (B1) and a mixture of (B1) and a small amount of (B2).

  Furthermore, if necessary, the molecular weight of the modified polyester resin can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (for example, diethylamine, dibutylamine, butylamine, laurylamine, and the like), and those obtained by blocking them (for example, ketimine compounds).

  The ratio of the amines (B) is the equivalent ratio [NCO] / [NCO] of the isocyanate group [NCO] in the polyester prepolymer (A) having an isocyanate group at the terminal and the amino group [NHx] in the amines (B). NHx] is usually 2/1 to 1/2, preferably 1.5 / 1 to 1 / 1.5, and more preferably 1.2 / 1 to 1 / 1.2. Here, in the formula of the amino group [NHx], x is 1 or 2, and the main body is 2.

  When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the modified polyester resin becomes low, and the hot offset resistance deteriorates.

  In the present invention, a modified polyester resin, that is, a urea-modified polyester (abbreviated as UMPE) can be used, but the UMPE may contain a urethane bond as well as 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.

  Moreover, the weight average molecular weight of UMPE is 10,000 or more normally, Preferably it is 20,000-10 million, More preferably, it is 30,000-1 million. If it is less than 10,000, the hot offset resistance deteriorates.

  The second binder resin made of the modified polyester resin is used in combination with the first binder resin that is soluble in THF and has a glass transition point of 30 to 46 ° C. As such a first binder resin, it is preferable to use an unmodified polyester resin, that is, a polyester not modified with urea (abbreviated as PE) as described above. For example, the combined use of PE improves the low-temperature fixability and the gloss when used in a full-color device.

  Examples of PE include polycondensates synthesized using the same polyol (PO) and polycarboxylic acid (PC) as the polyester component shown in the above UMPE, and preferred are the same as UMPE.

  In particular, it is preferable in terms of low-temperature fixability and hot offset resistance that at least a part of UMPE and PE is compatible in the toner. Therefore, it is preferable that the polyester component of UMPE and PE have a similar composition. The weight ratio of UMPE to PE is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, and particularly preferably 7/93 to 20/80. . When the weight ratio of UMPE 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 hydroxyl value (acid value) of PE to be used is usually 1-30, preferably 5-30, particularly preferably 5-20. Since PE has an acid value, it tends to be negatively charged, and further, the affinity between paper and toner is improved during fixing, and the low-temperature fixing property is improved. However, when the acid value exceeds 30, the stability of charging tends to be deteriorated due to environmental fluctuations. In addition, if the acid value of the resin fluctuates during the production of the toner, it leads to “blurring” in the granulation step in the polyaddition reaction, making it difficult to control the emulsification.

  As described above, the toner in the present invention includes at least a crystalline polyester binder resin, an amorphous polyester resin, a compound having an active hydrogen group, and a prepolymer having an isocyanate group capable of polyaddition reaction with the compound at the terminal. The colorant and the release agent (for example, wax) are dissolved or dispersed in an organic solvent, and the solution or dispersion is dispersed in an aqueous medium prepared by separately dispersing resin fine particles in water. After the compound and the prepolymer are polyaddition-reacted in the dispersion, the organic solvent is removed from the emulsified dispersion.

  The amines are used as the compound having an active hydrogen group, and a binder resin having a urea bond is formed by a polyaddition reaction, that is, an extension reaction and a crosslinking reaction, with a prepolymer having an isocyanate group at the terminal.

  For example, when the polyester prepolymer (A) having an isocyanate group at the terminal is used, as a method for stably forming a dispersion, each composition of the toner raw material is added to the aqueous medium and shearing force is added. And the like. The prepolymer (A) and other toner components (hereinafter referred to as toner raw materials), an unmodified polyester resin, a colorant (or colorant masterbatch), a release agent such as wax, and an optional charge The control agent or the like may be mixed when the dispersion is formed in the aqueous medium, but it is more preferable that the toner raw material is mixed in advance and then the mixture is added and dispersed in the aqueous medium.

  As an aqueous medium used for toner production in the present invention, water alone may be used, or a solvent miscible with water may be used in combination. Solvents miscible with water include alcohols (eg, methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolve), lower ketones (eg, acetone, methyl ethyl ketone, etc.), etc. Is mentioned.

  In addition, the dispersion method is not particularly limited, and equipment using a known method such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, or an ultrasonic wave can be applied. Here, in order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing method is preferable.

  When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. Similarly, the dispersion time is not particularly limited, but is usually 0.1 to 5 minutes in the case of a batch method. In general, the temperature during dispersion is preferably 20 ° C. or lower. This is to prevent aggregation of the pigment.

The amount of the aqueous medium used is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight, based on 100 parts of the toner composition comprising the toner raw material. If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 2000 parts by weight, it is not economical. Further, the viscosity of the oil phase at this time needs to be 2000 mP · s or more with a B-type viscometer. When the viscosity of the oil phase is less than 2000 mP · s, the pigment particles easily move in the dispersed oil phase and start to aggregate, so that the pigment dispersibility of the toner deteriorates and the volume specific resistance of the toner decreases. If the temperature is not maintained at 15 ° C. or lower even after the pigment is dispersed, the pigment particles tend to aggregate.

  Further, in order to lower the viscosity of the toner composition, an organic solvent in which the polyester prepolymer (A) having an isocyanate group at the terminal or the modified polyester (UMPE) formed by polyaddition reaction is soluble may be used. it can. The use of an organic solvent is preferred in that the particle size distribution becomes sharp. And as the said organic solvent, the thing whose boiling point is less than 100 degreeC is preferable from the point that it is easy to volatilize and is easy to remove.

  Examples of such organic solvents include 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 the organic solvent with respect to 100 parts of polyester prepolymer (A) which has an isocyanate group at the terminal is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When an organic solvent is used, the prepolymers (A) and (B) are heated and removed under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or cross-linking reaction time is selected depending on the reactivity difference determined by the combination of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 2 hours. 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 of such a catalyst include dibutyltin laurate and dioctyltin laurate.

  When the toner composition is used as a dispersion, a dispersant may be used as necessary. The use of a dispersant is preferable in that the particle size distribution becomes sharp and the dispersion is stable.

  The resin fine particles used in the case where the dissolved or dispersed toner raw material is dispersed in an aqueous medium prepared by dispersing resin fine particles in water to form an emulsified dispersion, has a glass transition point (Tg) of 50. It is important that it is -95 degreeC, and it is preferable that a weight average molecular weight is 100,000-300,000.

  When the glass transition point is less than 50 ° C., toner blocking is reduced, and when it exceeds 95 ° C., the toner particles are prevented from being softened during fixing.

  The resin fine particles adhere to the outermost surface of the toner particles after emulsification and form a toner structure that prevents blocking of the low softening resin contained in the toner particles (see FIG. 5).

  As the resin fine particles, an aqueous dispersion can be formed, and any resin fine particles can be used within the above Tg range. Examples of such resin fine particles include vinyl resins, polyurethane resins, epoxy resins, and polyester resins. Two or more of these resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.

  Examples of the vinyl resin include polymers obtained by homopolymerization or copolymerization of vinyl monomers. Specific examples include styrene- (meth) acrylic acid ester resins, styrene-butadiene copolymers, (meth) acrylic acid- Acrylic ester polymers, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like.

  In order to remove the organic solvent from the emulsified dispersion composed of fine droplet particles containing the organic solvent, the three types of binder resin, the colorant, and the wax, the entire system is gradually heated and the organic solvent in the droplets It is possible to employ a method of completely evaporating and removing. The toner circularity can be controlled by the strength of the liquid agitation before the solvent removal and the solvent removal time. That is, when the solvent is removed slowly, the shape becomes more spherical, which is 0.980 or more in terms of circularity. In addition, when the solvent is removed with strong stirring in a short time, irregularities and irregular shapes are obtained, and the degree of circularity is 0.900 to 0.960.

  As another solvent removal method, the emulsified dispersion is sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant is removed by evaporation. It is also possible to do. As a dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer or rotary kiln.

  When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classification into a desired particle size distribution.

  Moreover, the fine particle portion can be removed in the liquid by a classification operation such as a cyclone, a decanter, or centrifugation. Of course, the classification operation may be performed after drying and obtaining as a powder, but classification in a liquid is preferable in terms of efficiency. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, fine particles or coarse particles may be wet.

  The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

  In addition, the dried toner powder is mixed with different particles such as charge control fine particles and fluidizing agent fine particles, or fixed or fused on the toner surface by applying a mechanical impact force to the mixed powder. It is possible to prevent detachment of foreign particles from the surface of the resulting composite particles.

  As a specific means for giving mechanical impact force to the mixed powder, a method of applying impact force to the mixture by blades rotating at high speed, the mixture is thrown into a high-speed air stream, accelerated, and particles or composites There is a method of causing particles to collide with an appropriate collision plate. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) is modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron Examples include a system (manufactured by Kawasaki Heavy Industries, Ltd.) and an automatic mortar.

  Next, the release agent contained as a component of the toner used in the present invention will be described. A known wax having a melting point of 60 to 90 ° C. can be used as the release agent.

  Examples of the wax include polyolefin wax (for example, polyethylene wax); long chain hydrocarbon (for example, paraffin wax, sasol wax, etc.); carbonyl group-containing wax. Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (for example, carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1 , 18-octadecanediol distearate, etc.); polyalkanol esters (eg, tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (eg, ethylenediamine dibehenyl amide); polyalkylamides (eg, Trimellitic acid tristearyl amide, etc.); and dialkyl ketones (eg, distearyl ketone, etc.). Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred.

  The melting point of the wax of the present invention is usually 60 to 90 ° C, preferably 70 to 85 ° C. A wax having a melting point of less than 60 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 95 ° C. tends to cause a cold offset during fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps (5 to 1000 mPa · s), more preferably 10 to 100 cps (10 to 100 mPa · s) as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps (1000 mPa · s) have a poor effect of improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 1 to 20% by weight, preferably 3 to 10% by weight. In particular, in order to finely disperse the wax in the particles having a small particle size, the content of the wax is preferably maintained at 3 to 7% by weight.

  As the releasing agent, the various waxes described above can be used. As the toner in the present invention, vegetable wax is particularly suitable as described above. That is, it is preferable in terms of compatibility with other components in the present invention and releasability, and particularly those having a melting point of 60 ° C. to 90 ° C. are suitable.

  Next, the colorant contained as a component of the toner used in the present invention will be described. Known dyes and pigments can be used as the colorant.

Examples of the colorant used include 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 Tan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Faise Red, Parachlor Ortho Nitro Aniline red, resource Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine 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, Thioindigo Red B , Thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, claw Vermilion, 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, pyridiane, emerald green, pigment green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalocyanine Green, Anne Traquinone 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 used in the present invention can also be used in the form of a masterbatch combined with a resin. As the resin kneaded with the master batch during the production of the master batch, the modified polyester resin or the unmodified polyester resin mentioned above is used, and styrene such as polystyrene, poly p-chlorostyrene, polyvinyl toluene, and the substitution thereof. Polymer: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic Ethyl acid copolymer, Styrene-butyl acrylate copolymer, Styrene-octyl acrylate copolymer, Styrene-methyl methacrylate copolymer, Styrene-ethyl methacrylate copolymer, Styrene-butyl methacrylate copolymer , Styrene-α-Chlormetac Methyl formate copolymer, Styrene-acrylonitrile copolymer, Styrene-vinyl methyl ketone copolymer, Styrene-butadiene copolymer, Styrene-isoprene copolymer, Styrene-acrylonitrile-indene copolymer, Styrene-maleic acid Styrene copolymers such as copolymers, styrene-maleic acid ester copolymers; 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, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. Or they can be mixed.

  The master batch can be obtained by mixing and kneading a resin for a master batch selected from the above and a colorant under a high shear force. In this case, an organic solvent can be used in order to enhance the interaction between the colorant and the resin for the master batch. In addition, a so-called flushing method, which is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components, is also preferably used. According to this method, since the wet cake of the colorant can be used as it is, there is no need to dry it. For mixing and kneading, a high shearing dispersion device such as a three-roll mill is preferably used.

  Further, other additives used as necessary as the composition of the toner used in the present invention will be described.

(Charge control agent)
That is, the toner of the present invention may contain a charge control agent as necessary. Known charge control agents can be used. For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified) Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of nigrosine dye, Bontron P-51 of quaternary ammonium salt, Bontron S-34 of metal-containing azo dye, E-82 of oxynaphthoic acid metal complex, E of salicylic acid metal complex -84, phenolic condensate E-89 (above, Orient Chemical Industries), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary Copy charge PSY VP2038 of ammonium salt, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR- which is a boron complex 147 (manufactured by Nippon Carlit), copper phthalocyanine, perylene, quinaclide , Azo pigments, sulfonate group, carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  The amount of charge control agent used as the toner component is the kind of so-called binder resin composed of the first binder resin and the second binder resin, the presence or absence of other additives used as necessary, Although it is determined by a toner production method including a dispersion method and is not uniquely limited, it is preferably used in a range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. It is done. More preferably, the range of 0.2 to 5 parts by weight is good. When the amount exceeds 10 parts by weight, the chargeability of the toner becomes too high, and the effect as a charge control agent is diminished. As a result, the electrostatic attractive force with the developing roller increases, leading to a decrease in developer fluidity and a decrease in image density. These charge control agents can be melt-kneaded with the master batch and the resin, or may be added when dissolved and dispersed in an organic solvent.

  In order to assist fluidity, developability, chargeability and the like of the colored particles obtained by the granulation method, an external additive can be used as necessary. As the external additive, inorganic fine particles can be preferably used.

The primary particle size of such inorganic fine particles is preferably 5 mμ to 2 μm, and particularly preferably 5 mμ to 500 mμ. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight.

  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, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

  In addition to the above inorganic fine particles, polymer fine particles, for example, polystyrene particles obtained by soap-free emulsion polymerization, suspension polymerization or dispersion polymerization, polymer particles made of methacrylic acid ester or acrylic acid ester copolymer, or silicone, benzoguanamine, Polymer particles comprising a polycondensation system such as nylon or a thermosetting resin can be used.

  Such an external additive, for example, a fluidizing agent, can be prevented from being deteriorated in flow characteristics and charging characteristics even under high humidity by performing surface treatment to increase hydrophobicity. Preferred examples of the surface treatment agent include a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone. Examples include oil.

  Further, a cleaning property improving agent for removing the developer after transfer remaining on the photosensitive member or the primary transfer medium can be used as an external additive.

  Examples of the cleaning property improver include fatty acid metal salts such as zinc stearate, calcium stearate and stearic acid, or polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. . The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

  The toner of the present invention obtained as described above can be used as a one-component magnetic toner that does not use a carrier, or a non-magnetic toner, or it can be used as a two-component developer that uses a carrier. it can.

  When the toner of the present invention is used as a two-component developer, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 1 to 10 wt. Part is preferred.

  As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Examples of the coating material include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, polystyrene resins and styrene acrylic copolymer resins, Halogenated olefin resins such as vinyl chloride, polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, polycarbonate resins, polyethylene resins, polyvinyl fluoride resins, polyvinylidene fluoride resins, polytrifluoroethylene resins, polyhexa Fluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride Dorukatan monomer and fluoroterpolymers such as terpolymers of, and silicone resins. Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.

  In the image forming method of the present invention, other matters that are preferably applied will be described. First, among the means used in the image forming process, at least one means selected from a photoconductor, a charging means, a developing means containing a developer, and a cleaning means is integrally supported, and the image forming apparatus main body It is preferable to use a process cartridge which is detachable.

(Process cartridge)
An example of the process cartridge in the present invention is shown in the schematic configuration diagram of FIG.

  In FIG. 6, a process cartridge 500 includes a charging unit 502, a developing unit 503, and a cleaning unit 504 as constituent elements around a photosensitive member 501, and this process cartridge is attached to a main body of an image forming apparatus such as a copying machine or a printer. And detachable. The toner used in the present invention is stored in the developing unit 503 as a two-component developer, for example.

  If the process cartridge is used in the image forming method of the present invention, the image apparatus can be made compact, and simple and steady maintenance work can be performed. Furthermore, it is possible to easily replace the parts and to stabilize the image quality. Also, it is possible to restore the original high-quality image simply by replacing the process cartridge.

  If the photoconductor used in the image forming process of a high-speed copying machine or a laser beam printer (LBP) is an amorphous silicon photoconductor, the surface hardness is high, and a long wavelength light such as a semiconductor laser (770 to 800 nm) is used. Therefore, even when high-speed printing is performed using the toner according to the present invention, it is possible to form an image with higher quality and higher definition.

  In addition, as the electrophotographic photoreceptor used in the present invention, a conductive support is heated to 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, An amorphous silicon photoreceptor having a photoconductive layer made of a-Si can be used by a film forming method such as a photo CVD method or a plasma CVD method. Among them, for example, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support can be preferably used.

  Furthermore, if the latent image forming step is performed by applying an alternating electric field, a vibration bias voltage obtained by superimposing an AC voltage on a DC voltage is applied when developing the latent image on the photosensitive member by the developing device. A high-definition image with no image is obtained, and the stability of the image quality is improved.

  That is, by applying an oscillating bias voltage in which an AC voltage is superimposed on a DC voltage, the difference between the peak value at which the toner is directed to the photoconductor and the time average value of the bias can be increased. The toner becomes more active, and the toner adheres faithfully to the potential distribution on the latent image surface, thereby improving the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

  In the charging process of the photoconductor, if the charging member is brought into contact with the photoconductor and a voltage is applied to the charging member, the amount of ozone is remarkably reduced, so that there is no environmental problem. A quality image can be formed.

  As the charging device, for example, roller charging, fur brush charging, magnetic brush charging, or the like can be applied, and can be selected according to a request for providing high image quality.

  Then, in the image forming method according to the present invention, when an image forming apparatus equipped with the process cartridge containing the developer is used, reverse transfer to the recording medium by melting of the toner fixed to the cleaning member according to the present invention is performed. Preventing and stable fixing. In addition, low-temperature fixability, hot offset resistance, heat-resistant storage stability, and fluidity are balanced, and there is no fog, high image density, and high-definition image formation from low speed to high-speed image forming apparatuses. .

  In this embodiment, as described above, the base material 13a is formed of a material in which a magnetic shunt alloy is dispersed. Here, the Curie temperature of the magnetic shunt alloy is set lower than the hot offset temperature of the toner. For example, when the hot offset temperature in the fixing device 10 is 205 ° C., a powder made of, for example, an iron-nickel alloy is dispersed in the resin of the base material 13a so that the Curie temperature of the magnetic shunt alloy is 200 ° C. (The amount of nickel is adjusted so that the Curie temperature of the magnetic shunt alloy is 200 ° C.).

  When the fixing device 10 of FIG. 1 includes the fixing belt 13 shown in FIG. 2, when a high frequency current is passed through the induction coil 14, the base material 13 a of the fixing belt 13 is heated by electromagnetic induction and the fixing belt 13 generates heat. . Then, by passing the recording paper P conveyed on the guide plate 20 between the fixing roller 11 and the pressure roller 16, unfixed toner on the recording paper P can be fixed.

  Further, in the fixing device 10 having the above-described configuration, even if small-sized recording paper is continuously fed, the temperature distribution along the width direction of the fixing belt 13 is about 200 ° C. at both ends as shown in FIG. Therefore, hot offset can be prevented from occurring at both ends of the fixing roller 13 even if a large size sheet is passed after a small size recording sheet is continuously fed.

Example A
In the present embodiment, as described above, the base member 13a is formed of a material in which the magnetic shunt alloy is dispersed. Here, the Curie temperature of the magnetic shunt alloy is set lower than the hot offset occurrence temperature of the toner. For example, when the hot offset occurrence temperature in the fixing device 10 is 205 ° C., a powder made of, for example, an iron-nickel alloy is contained in the resin of the base material 13 a so that the Curie temperature of the magnetic shunt alloy is 200 ° C. Dispersed (the amount of nickel is adjusted so that the Curie temperature of the magnetic shunt alloy is 200 ° C.).

  When the fixing device 10 of FIG. 1 includes the fixing belt 13 shown in FIG. 2, when a high frequency current is passed through the induction coil 14, the base material 13 a of the fixing belt 13 is heated by electromagnetic induction and the fixing belt 13 generates heat. . By passing the recording paper P conveyed on the guide plate 20 between the fixing roller 11 and the adding roller 16, the unfixed toner on the recording paper P can be fixed.

  Further, in the fixing device 10 configured as described above, even if small-sized recording paper is continuously fed, the temperature distribution along the width direction of the fixing belt 13 is about 200 ° C. at both ends as shown in FIG. Therefore, hot offset can be prevented from occurring at both ends of the fixing roller 13 even if a large size sheet is passed after a small size recording sheet is continuously fed.

Example B
FIG. 8 shows a second embodiment of the present invention, and is a cross-sectional view of only the upper half of the facing roller 12. As shown in the figure, the facing roller 12 has a cylindrical portion 12a, and rotation support portions 12b are provided at both ends of the cylindrical portion 12a. The rotation support portion 12b is supported by the image forming apparatus main body via a bearing.

  In this embodiment, both end portions of the inner wall surface of the facing roller 12 are cut off, and the cylindrical portion 12a is formed so that the both end portions 12d are thinner than the central portion 12c along the axial direction of the facing roller 12. Yes. For example, the thickness of the central portion 12c is 0.6 mm, and the thickness of both end portions 12d is 0.3 mm.

With such a configuration, the heat capacity at both end portions 12d of the opposing roller 12 is reduced, and heat from electromagnetic induction heating can be prevented from escaping to the both end portions 12d side. As a result, as shown in FIG. 9 , the temperature rise at both end portions 12d (opposite roller both end portions) is almost equal to the temperature rise at the central portion 12c (opposite roller center portion), and as a result, the fixing device can be used. It is possible to shorten the time until it is, that is, the rise time.

Comparative Example A
In the case of Example A or Example B, the fixing belt 13 contains a magnetic shunt alloy, but in this comparative example, the fixing belt 13 does not contain a magnetic shunt alloy.

(Example of toner)
Hereinafter, the toner of the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, all the description of a part shows a weight part.

(Production Example A)
~ Synthesis of crystalline polyester A ~
Into a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 2070 g of 1,4-butanediol, 2535 g of fumaric acid, 191 g of trimellitic anhydride, and 4.9 g of hydroquinone were added. After reacting at 5 ° C. for 5 hours, the temperature was raised to 200 ° C. and reacted for 1 hour, and further reacted at 8.3 kPa for 1 hour to obtain a crystalline polyester resin. DSC endothermic peak temperature was 86 ° C., Mn710, Mw2100.

(Production Example B)
~ Synthesis of crystalline polyester B ~
In a 5-liter four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, 1,70-butanediol 2070 g, glycerin 555 g, fumaric acid 2535 g, trimellitic anhydride 291 g, hydroquinone 4.9 g The mixture was reacted at 160 ° C. for 5 hours, heated to 200 ° C. for 1 hour, and further reacted at 8.3 kPa for 1 hour to obtain a crystalline polyester resin. DSC endothermic peak temperature was 69 ° C., Mn710, Mw2100.

<Example 1>
Under the following conditions, the raw materials used for the production of the toner particles were synthesized or prepared to produce the toner of Example 1.

<Production Example 1: Synthesis of organic fine particle emulsion and preparation of resin fine particle dispersion (1)>
In a reaction vessel equipped with a stir bar and a thermometer, water 838 parts, sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 73 parts of styrene, 92 parts of methacrylic acid, When 130 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. The system was heated to raise the system temperature 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, and an aqueous vinyl resin (a copolymer of sodium salt of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate). A dispersion [resin fine particle dispersion (1)] was obtained. When the resin fine particle dispersion (1) was measured by LA-920, the volume average particle diameter was 90 nm. A part of the resin fine particle dispersion (1) was dried to isolate the resin component. The Tg of the resin was 57 ° C., and the weight average molecular weight was 200,000.

<Production Example 2: Preparation of aqueous phase (1)>
Mixing 990 parts of water, 83 parts of [resin fine particle dispersion (1)], 37 parts of 48.5% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7: Sanyo Chemical Industries) and 90 parts of ethyl acetate Agitation gave a milky white liquid. This is designated as [aqueous phase (1)].

<Production Example 3: Synthesis of unmodified polyester (non-crystalline polyester (a))>
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 724 parts of bisphenol A ethylene oxide 2-mole adduct, 138 parts of terephthalic acid and 138 parts of isophthalic acid were subjected to polycondensation at 210 ° C. for 10 hours under normal pressure. After reacting at a reduced pressure of 10 to 15 mmHg for 5 hours, cooling to 160 ° C., adding 18 parts of phthalic anhydride to this and reacting for 2 hours, polyester (a), not modified with a so-called urethane bond [unmodified polyester (A)] was obtained. This unmodified polyester (a) corresponds to the first binder resin. Tg of unmodified polyester (a) was 42 ° C., MW 28000, peak top 3500, and acid value 15.3.

<Production Example 4: Synthesis of isocyanate group-containing prepolymer (1)>
724 parts of bisphenol A ethylene oxide 2-mole adduct, 274 parts of isophthalic acid, 20 parts of trimellitic anhydride, and 2 parts of dibutyltin oxide are placed in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, and at normal pressure. The reaction was carried out at 230 ° C. for 8 hours, followed by further reaction for 5 hours while dehydrating at a reduced pressure of 10 to 15 mmHg, followed by cooling to 160 ° C. and addition of 32 parts of phthalic anhydride to the reaction for 2 hours. Next, the mixture was cooled to 80 ° C., reacted with 188 parts of isophorone diisocyanate in ethyl acetate for 2 hours, and a polyester prepolymer (1) containing an isocyanate group at the terminal, abbreviated as [isocyanate group-containing prepolymer (1)]. Got.

This isocyanate group-containing prepolymer (1) is a modified polyester (second binder resin) modified with a urea bond by polyaddition reaction with the following ketimine compound (1) having an active hydrogen group in the granulation process. ).

<Production Example 5: Production of ketimine compound (1)>
In a reaction vessel equipped with a stirring bar and a thermometer, 30 parts of isophoronediamine and 70 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain [ketimine compound (1)].

<Production Example 6: Production of master batch (1)>
1200 parts of water, 540 parts of carbon black (Printex35: manufactured by Dexa) and 1200 parts of a polyester resin (unmodified polyester (b) described in Example 5) were added and mixed with a pressure kneader. The mixture was kneaded with two rolls at 150 ° C. for 30 minutes, rolled and cooled, and pulverized with a pulverizer to obtain [Masterbatch (1)]. Carbon DB used had a DBP oil absorption of 42 ml / 100 mg and a pH of 9.5.

<Production Example 7: Production of pigment / WAX, crystalline polyester, dispersion (1)>
In a container in which a stirring bar and a thermometer are set, 120 parts of crystalline polyester [unmodified polyester (a)] 378 parts, 100 parts of carnauba wax (WAX), 20 parts of a wax dispersant, (styrene / acrylonitrile / N-BMA) Copolymer) 947 parts of ethyl acetate were charged, the temperature was raised to 80 ° C. with stirring, the temperature was maintained at 80 ° C. for 5 hours, and then cooled to 30 ° C. in 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)] 1324 parts are transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex), liquid feeding speed: 1 kg / hr, disk peripheral speed: 6 m / sec, 0.5 mm zirconia beads The carbon black and WAX were dispersed under the condition of 80% by volume and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [unmodified polyester (a)] was added, and the mixture was passed through a bead mill under the above conditions for 3 passes to obtain [Dispersion (1)].

(Example of toner production: Toner (1))
(I) Emulsification and solvent removal process:
749 parts of [Pigment / WAX dispersion (1)], 115 parts of [Isocyanate group-containing prepolymer (1)] and 2.9 parts of [Ketimine compound (1)] prepared above were put in a container, respectively. (Made by Special Machine) was mixed for 1 minute at a rotation speed of 5,000 rpm. After mixing, 1000 parts of [Aqueous Phase (1)] was added to the container, and mixed for 5 minutes at 5,000 rpm with Filmix (made by Tokushu Kika) to obtain [Emulsified Slurry (1)]. . The liquid temperature at this time was kept at 20 ° C. ± 2 ° C., and ripened for 3 hours after emulsification. The emulsified particle size was measured with a Coulter Multisizer particle size distribution meter, and the reaction was terminated when it reached a predetermined 4 to 5 μm.

  [Emulsified slurry (1)] was put into a container equipped with a stirrer and a thermometer, and stirred at a stirring speed of 5 m / s or more to obtain spindle-shaped toner particles. Thereafter, the solvent was removed at 30 ° C. for 8 hours to obtain [Dispersed slurry (1)].

(B) Cleaning and drying process:
After filtering 100 parts of the above [emulsified slurry (1)] under reduced pressure, the following processes (a) to (d) were carried out to obtain [filter cake (1)].
(A): 100 parts of ion-exchanged water was added to the filter cake filtered under reduced pressure, and the mixture was mixed with a TK homomixer at 12,000 rpm for 10 minutes, followed by filtration.
(B): 100 parts of a 10% sodium hydroxide aqueous solution was added to the filter cake of (a), mixed with a TK homomixer at 12,000 rpm for 30 minutes, and then filtered under reduced pressure.
(C): 100 parts of 10% hydrochloric acid was added to the filter cake of (b), mixed with a TK homomixer at 12,000 rpm for 10 minutes, and then filtered.
(D): 300 parts of ion-exchanged water was added to the filter cake of (c), mixed with a TK homomixer at 12,000 rpm for 10 minutes, and then filtered twice. This obtained [Filter cake (1)].

  The filter cake (1) was dried for 48 hours at 45 ° C. with a circulating dryer, and sieved with a mesh of 75 μm mesh [matrix particles (1) as a colored powder].

(C) Preparation of base particles (1) which are colored powders:
Next, 0.25 parts of a charge control agent (Bontron E-84: manufactured by Orient Chemical Co., Ltd.) is added to 100 parts of [matrix particles (1) as a colored powder] obtained above, and a Q-type mixer (Mitsui Mining Co., Ltd.), the peripheral speed of the turbine blades was set to 50 m / sec, and a 2-minute operation-1-minute pause process was performed for 5 cycles. The total processing time was 10 minutes.

  Furthermore, 0.5 part of hydrophobic silica (H2000: manufactured by Clariant Japan) was added, the peripheral speed was 15 m / sec, mixing for 30 seconds and resting for 1 minute was performed for 5 cycles, black toner (1), abbreviated. [Toner (1)] was obtained.

  The specifications and properties of the obtained [Toner (1)] are shown in Table 1 below.

  The binder resin (Tg), the ratio between the first and second binder resins, the release agent (type, melting point), and the toner particle size distribution (Dv, Dn, Dv /) in the evaluation items shown in Table 1. Dn, particle sizes of 3 μm or less and 8 μm or more), toner shape and fine particle content (particle content of 2 μ or less, circularity), toner properties (1/2 outflow temperature T1) according to the measurement method It was measured.

  In addition, using the obtained [Toner (1)], the RICOH imagio Neo C385 remodeling machine equipped with a fixing device using a magnetic shunt alloy for the electromagnetic induction heating method was used for low temperature fixing, hot offset resistance, The resolution, image density, and powder fluidity were evaluated. The evaluation results are shown in Table 2 below. Each evaluation method is as follows.

[Evaluation method of powder flowability]
The bulk density was measured using a powder tester made by Hosokawa Micron. The toner with better fluidity has a higher bulk density. Evaluation was performed in the following four stages.
X: Bulk density is less than 0.25,
Δ: Bulk density is 0.25 to 0.30,
○: Bulk density is 0.30 to 0.35,
A: Bulk density is 0.35 or more [Low-temperature fixability; Evaluation method of minimum fixing temperature]
Ricoh type 6200 paper was set and a copy test was conducted. The low temperature fixing property was evaluated by setting the heating roll temperature at which the residual ratio of the image density after rubbing the fixed image with a pad to 70% or more was set as the minimum fixing temperature.

[Hot offset property; Evaluation method of hot offset occurrence temperature]
The fixing was evaluated in the same manner as the above-mentioned fixing lower limit temperature, and the presence or absence of hot offset to the fixed image was visually evaluated. The hot offset property was evaluated using the heating roll temperature at which hot offset was generated as the hot offset generation temperature.

[Evaluation of heat-resistant storage stability]
<Measurement instrument>
Needle penetration tester (Nikka Engineering), tapping machine, 30 mL screw vial.

<Storage>
Constant temperature layer <Method>
(1) Collect 10g of toner in a 30ML screw vial,
(2) Apply the toner of (1) to the tapping machine 150 times / 1 minute 35 seconds,
(3) Keep quietly in a constant temperature bath at a predetermined temperature of 50 ° C. for 24 hours,
(4) Take out from the thermostatic chamber after 24 hours and rest for 2 hours.
(5) Drop the needle with a penetration tester and test the penetration. <Criteria>
○: 16 mm or more
Δ: 10 to 15 mm,
×: 10 mm or less [Evaluation of image density]
<Preparation of developer>
50 parts of toner having a particle diameter of 4 to 6 μm and 950 parts of a silicone resin film carrier (silicon resin: KR250 manufactured by Shin-Etsu Chemical Co., Ltd., core material carrier 100 μm) were shaken in a mixer for 20 minutes to obtain a developer.

<Live-action test>
10,000 photographs were taken continuously under a high temperature and high humidity environment (30 ° C./80% RH). The image density and resolving power at the initial stage and after 10,000 actual shots were evaluated by the following evaluation methods.
<Evaluation method / Image density>
The relative density with respect to the copy image of the solid portion having an original density of 1.38 was measured with a Macbeth densitometer to obtain an image density.

(Criteria)
○: Difference between initial density and 10,000-sheet copy density is within 0.10,
Δ: The difference between the initial density and the 10,000-sheet copy density is 0.11 to 0.20,
×: Difference between initial density and 10,000-sheet copy density is 0.21 or more [resolution evaluation]
The resolution is 2.0, 2.2, 2.5, 2.8, 3.2, 3.6, 4.0, 4.5, 5.0, 5. For a line image in which 6, 6.3, and 7.1 lines are arranged at equal intervals, it is evaluated how faithfully the copied image can be reproduced between the lines. That is, the number per 1 mm that can be reproduced is the resolution.

(Criteria)
○: 6.3 pieces / mm or more,
Δ: 5.0 to 5.6 pieces / mm,
×: 4.5 / less < Reference Example 2>
[Toner (2)] in the same manner as in Example 1 except that [Dispersion (1)] used in Example 1 was replaced with [Pigment / WAX dispersion (2)] prepared in Preparation Example 8 below. Got. The specifications and properties of the obtained [Toner (2)] are shown in Table 1 below. Further, using the obtained [Toner (2)], the results of evaluation regarding low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, and powder fluidity were conducted in the same manner as in Example 1. Is shown in Table 2 below.

<Production Example 8: Production of dispersion (2)>
In [Production Example 7: Production of Dispersion (1)] in Example 1 above, the crystalline polyester was changed to Production Example B, and [Dispersion (2)] was produced in the same manner as in Production Example 7.

<Example 3>
[Toner] in the same manner as in Example 1, except that [Pigment / WAX / Crystalline polyester dispersion (1)] used in Example 1 was replaced with [Dispersion (3)] produced in Production Example 9 below. (3)] was obtained. The specifications and properties of the obtained [Toner (3)] are shown in Table 1 below. In addition, the obtained [Toner (3)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, and powder fluidity in the same manner as in Example 1. Is shown in Table 2 below.

<Production Example 9: Production of Pigment / WAX / Crystalline Polyester Dispersion (3)>
The same procedure as in Production Example 7 except that 10 parts of carnauba wax (WAX) used in <Production Example 7: Production of pigment / WAX dispersion (1)> in Example 1 was replaced with 15 parts of rice wax. Dispersion (3)] was produced.

<Example 4>
[Toner (4)] in the same manner as in Example 1 except that [Pigment / WAX Dispersion (1)] used in Example 1 was replaced with [Dispersion (4)] prepared in Preparation Example 10 below. Got. The first binder resin is [unmodified polyester (a)]. The specifications and properties of the obtained [Toner (4)] are shown in Table 1 below. In addition, the obtained [Toner (4)] was evaluated in the same manner as in Example 1 for low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, and powder fluidity. The results are shown in Table 2 below.

<Production Example 10: Production of pigment / WAX dispersion (4)>
The same procedure as in Production Example 7 except that 10 parts of carnauba wax (WAX) used in <Production Example 7: Production of pigment / WAX dispersion (1)> in Example 1 was replaced with 20 parts of candelilla wax. [Pigment / WAX dispersion (4)] was produced.

<Example 5>
[Unmodified polyester (a)] used in Example 1 was replaced with [Unmodified polyester (b)] prepared in Preparation Example 11 below, and [Pigment / WAX dispersion (1)] was prepared in Preparation Example 13 below. [Toner (5)] was obtained in the same manner as in Example 1 except that the [Pigment / WAX dispersion (5)] was used. The specifications and properties of the obtained [Toner (5)] are shown in Table 1 below. In addition, the obtained [Toner (5)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, and powder fluidity in the same manner as in Example 1. Is shown in Table 2 below.

<Production Example 11: Synthesis of unmodified polyester (b) (non-crystalline polyester resin)>
In a reaction vessel equipped with a condenser, a stirrer, and a nitrogen introduction tube, 196 parts of bisphenol A propylene oxide 2-mole adduct, 553 parts of bisphenol A ethylene oxide 2-mole adduct, 210 parts of terephthalic acid, 79 parts of adipic acid and dibutyl Add 2 parts of tin oxide, react for 8 hours at 230 ° C. under normal pressure, and further react for 5 hours under reduced pressure of 10 to 15 mmHg, then add 26 parts of trimellitic anhydride into the reaction vessel at 180 ° C. and upper pressure. By reacting for 2 hours, [unmodified polyester (b)] was obtained. [Unmodified polyester (b)] had a number average molecular weight of 6,200, a weight average molecular weight of 36,000, Tg of 33 ° C., and an acid value of 15.

<Production Example 12: Production of master batch (2)>
1200 parts of water, 540 parts of carbon black (Regal 400R: manufactured by Cabot) (pH = 4.0), 1200 parts of the modified polyester resin (b) are added and mixed with a pressure kneader, and the mixture is 150 ° C. using two rolls. After kneading for 30 minutes, it was cooled by rolling and pulverized with a pulverizer to obtain [Masterbatch (2)].

<Production Example 13: Production of pigment / WAX dispersion (5)>
In a container equipped with a stir bar and a thermometer, 378 parts of the above [unmodified polyester (b)], 110 parts of carnauba wax, 50 parts of a wax dispersant ((styrene / acrylonitrile / N-BMA copolymer) ethyl acetate 947 The mixture was heated to 80 ° C. with stirring and held at 80 ° C. for 5 hours, and then cooled to 30 ° C. over 1 hour, and then 500 parts of [Masterbatch (2)] and 500 parts of ethyl acetate. Were mixed for 1 hour to obtain [Raw material solution (2)].

  [Raw material solution 2] 1324 parts are transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), a liquid feeding speed of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 0.5 mm zirconia beads are 80% by volume. Carbon black and WAX were dispersed under conditions of filling and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [unmodified polyester b] was added, followed by 3 passes through the bead mill under the above conditions to obtain [Dispersion (5)].

<Comparative example 1>
After adding 451 g of 0.1M-Na ₃ PO ₄ aqueous solution to 709 g of ion-exchanged water and heating to 60 ° C., the mixture was stirred at 12,000 rpm using a TK homomixer. To this, 68 g of 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ .

  170 g of styrene, 30 g of 2-ethylhexyl acrylate, 3.4 g of ethylene glycol diacrylate, 10 g of legal 400R, 20 g of paraffin wax (sp. 70 ° C.), 5 g of a metal compound of di-tert-butylsalicylate, styrene-methacrylic acid copolymer ( 10 g of Mw 50,000, acid value 20 mgKOH / g) was put into a TK homomixer, heated to 60 ° C., and uniformly dissolved and dispersed at 12,000 rpm. In this, 10 g of a polymerization initiator, 2,2'-azobis (2,4-dimethylvaleronitrile), was dissolved to prepare a polymerizable monomer system.

The polymerizable monomer system was put into the aqueous medium and stirred at 10,000 rpm for 20 minutes in a TK homomixer at 60 ° C. in an N ₂ atmosphere to granulate the polymerizable monomer system. Then, after making it react with a paddle stirring blade for 3 hours at 60 degreeC, liquid temperature was made 80 degreeC and it was made to react for 10 hours. After completion of the polymerization reaction, the mixture was cooled and hydrochloric acid was added to dissolve calcium phosphate, followed by filtration, washing with water and drying to obtain [Toner (Comparative 1)].

  The specifications and properties of the obtained [Toner (Comparative 1)] are shown in Table 1 below. Table 2 below shows the results of evaluating the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, and powder fluidity using the obtained [Toner (Comparative 1)]. In the case of Example A or Example B, the fixing belt 13 contained a magnetic shunt alloy in the fixing belt 13 in this embodiment, but the fixing belt 13 contained a magnetic shunt alloy. Not used RICOH imagio Neo C385 remodeling machine.

<Comparative example 2>
Under the following conditions, the raw materials used for the production of comparative toner particles were synthesized or prepared to produce a toner (Comparative 2).

<Production Example 14: Preparation of aqueous wax particle dispersion (1)>
A 1000 ml stirrer, temperature sensor, nitrogen inlet tube and four-headed Kolben with cooling tube, 500 ml of degassed distilled water, 28.5 g of New Coal 565C (manufactured by Nippon Emulsifier Co., Ltd.), 1 (manufactured by Noda Wax Co., Ltd.) 185.5 g was added, and the temperature was raised while stirring under a nitrogen stream. When the internal temperature was 85 ° C., a 5N sodium hydroxide aqueous solution was added, and the temperature was raised to 75 ° C. as it was. In this state, heating and stirring were continued for 1 hour, followed by cooling to room temperature, to obtain [Wax Particle Aqueous Dispersion (1)].

<Preparation of Colorant Dispersion (I)>
After adding 100 g of carbon black (trade name: Mogal L, manufactured by Cabot Corporation) and 25 g of sodium dodecyl sulfate to 540 ml of distilled water and sufficiently stirring, a pressure type disperser (MINI-LAB: manufactured by Lani Corporation) was used. Dispersion was performed to obtain [Colorant Dispersion Liquid (I)].

<Production Example 15: Synthesis of high molecular weight and low molecular weight binder fine particle dispersion>
A 1 L 4-head Kolben equipped with a stirrer, cooling tube, temperature sensor and nitrogen inlet tube is 480 ml of distilled water, 0.6 g of sodium dodecyl sulfate, 106.4 g of styrene, 43.2 g of n-butyl acrylate, 10.4 g of methacrylic acid. The mixture was heated to 70 ° C. under a nitrogen stream while stirring. Here, an initiator aqueous solution prepared by dissolving 2.1 g of potassium persulfate in 120 ml of distilled water was added, and the mixture was stirred at 70 ° C. for 3 hours under a nitrogen stream to complete the polymerization. A binder fine particle dispersion (1)] was obtained.

  In addition, 5L 4-headed Kolben equipped with a stirrer, cooling pipe, temperature sensor and nitrogen inlet pipe, 2400 ml of distilled water, 2.8 g of sodium dodecyl sulfate, 620 g of styrene, 128 g of n-butyl acrylate, 52 g of methacrylic acid and tert-dodecyl 27.4 g of mercaptan was added, and the temperature was raised to 70 ° C. under a nitrogen stream while stirring. Here, an initiator aqueous solution in which 11.2 g of potassium persulfate was dissolved in 600 ml of distilled water was added, and the mixture was stirred at 70 ° C. for 3 hours under a nitrogen stream to complete the polymerization, and then cooled to room temperature. Molecular weight binder fine particle dispersion (2)] was obtained.

<Production Example 16: Synthesis of Toner (Comparative 2)>
In a 1 L separable flask equipped with a stirrer, a condenser, and a temperature sensor, 47.6 g of [high molecular weight binder fine particle dispersion (1)], [low molecular weight binder fine particle dispersion (2)] 190.5 g, [wax particles 7.7 g of aqueous dispersion (1)], 26.7 g of [colorant dispersion (I)] and 252.5 ml of distilled water were added, mixed and stirred, and then pH = 9 using 5N aqueous sodium hydroxide solution. The adjustment was made to .5. Further, with stirring, a sodium chloride aqueous solution in which 50 g of sodium chloride was dissolved in 600 ml of distilled water, 77 ml of isopropanol and 10 mg of Fluorado FC-170C (manufactured by Sumitomo 3M: fluorinated nonionic surfactant) dissolved in 10 ml of distilled water. Aqueous agent aqueous solution was sequentially added, the internal temperature was raised to 85 ° C., the reaction was performed for 6 hours, and then cooled to room temperature. This reaction solution was adjusted to pH = 13 with 5N-aqueous sodium hydroxide solution and then filtered. Further, resuspension was performed in distilled water, filtration and resuspension were repeated, washed, and dried to obtain [Toner (Comparative 2)]. The specifications and properties of the obtained [Toner (Comparative 2)] are shown in Table 1 below. Further, the obtained [Toner (Comparative 2)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, powder fluidity, and occurrence of toner contamination due to toner dissolution. Is shown in Table 2 below.

<Comparative Example 3>
[Toner] in the same manner as in Example 1 except that [Pigment / WAX dispersion (1)] used in Example 1 was replaced with [Pigment / WAX dispersion (Comparative 3)] prepared in Preparation Example 17 below. (Comparison 3)] was obtained.

<Production Example 17: Production of pigment / WAX dispersion (Comparative 3)>
In the same manner as in Production Example 7 except that 55 parts of carnauba wax (WAX) used in <Production Example 7: Production of Pigment / WAX Dispersion (1)> in Example 1 was changed to [Pigment / WAX dispersion (Comparative 3)] was produced.

  The specifications and properties of the obtained [Toner (Comparative 3)] are shown in Table 1 below. Further, the obtained [Toner (Comparative 3)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, powder fluidity, and occurrence of toner contamination due to toner dissolution. Is shown in Table 2 below.

<Comparative example 4>
[Toner] in the same manner as in Example 1 except that [Pigment / WAX dispersion (1)] used in Example 1 was replaced with [Pigment / WAX dispersion (Comparative 4)] prepared in Preparation Example 18 below. (Comparison 4)] was obtained.

<Production Example 18: Production of pigment / WAX dispersion (Comparative 4)>
The same procedure as in Production Example 7 except that 55 parts of carnauba wax (WAX) used in <Production Example 7: Production of Pigment / WAX Dispersion (1)> in Example 1 was replaced with 55 parts of polypropylene wax. [Pigment / WAX dispersion (Comparative 4)] was obtained.

  The specifications and properties of the obtained [Toner (Comparative 4)] are shown in Table 1 below. Further, the obtained [Toner (Comparison 4)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, powder fluidity, and toner contamination due to toner dissolution. Is shown in Table 2 below.

<Comparative Example 5>
(Example of toner production)
In a beaker, 15.4 parts of [isocyanate group-containing prepolymer (1)], 64 parts of [unmodified polyester (b)] and 78.6 parts of ethyl acetate were stirred and dissolved. Next, 20 parts of pentaerythritol tetrabehenate and 10 parts of carbon (REAMAL400R: manufactured by Cabot) were added, and the mixture was stirred at 12,000 rpm with a TK homomixer at 60 ° C., and uniformly dissolved and dispersed. Finally, 2.7 parts of [ketimine compound (1)] used in Example 1 were added and dissolved. This is designated as [toner material solution (1)].

  In a beaker, 706 parts of ion-exchanged water, 294 parts of hydroxyapatite 10% suspension (Nippon Kagaku Kogyo Super Tight 10) and 0.2 part of sodium dodecylbenzenesulfonate were uniformly dissolved. Next, the temperature was raised to 60 ° C., and while stirring at 12,000 rpm with a TK homomixer, [Toner material solution (1)] was added and stirred for 10 minutes. Next, this mixed solution was transferred to a Kolben equipped with a stirrer and a thermometer, heated to 55 ° C., and the solvent was removed under the condition of 25 to 50 mmHg while causing urea reaction, followed by filtration, washing and drying. After that, the wind was classified. Next, 100 parts of toner particles were mixed with 0.5 part of colloidal silica (Aerosil R972: manufactured by Nippon Aerosil) using a sample mill to obtain [Toner (Comparative 5)]. The specifications and properties of the obtained [Toner (Comparative 5)] are shown in Table 1 below. Further, the obtained [Toner (Comparative 5)] was used to evaluate the low temperature fixing property, hot offset property, heat resistant storage property, resolving power, image density, powder fluidity, and occurrence of toner contamination due to toner dissolution. Is shown in Table 2 below.

<Comparative Example 6>
A toner was prepared in the same manner as in Example 1 except that [Non-modified polyester (a)] used in Example 1 was replaced with [Non-modified polyester (d)] produced as follows. [Toner (Comparison 6)] was obtained. The specifications and properties of the obtained [Toner (Comparative 6)] are shown in Table 1 below. In addition, the obtained [Toner (Comparative 6)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, powder fluidity, and occurrence of toner contamination due to toner dissolution. Is shown in Table 2.

<Production of comparative unmodified toner binder (4)>
Bisphenol A ethylene oxide 2-mole adduct 325 parts and terephthalic acid 155 parts were polycondensed using 2 parts of dibutyltin oxide as a catalyst to obtain [unmodified polyester (d)]. The Tg of this [unmodified polyester (d)] was 61 ° C. The unmodified polyester (d) corresponds to the first binder resin in the toner composition.

  The specifications and properties of the obtained [Toner (Comparative 6)] are shown in Table 1 below. Further, the obtained [Toner (Comparative 6)] was used to evaluate the low-temperature fixing property, hot offset property, heat-resistant storage property, resolving power, image density, powder fluidity, and occurrence of toner contamination due to toner dissolution. Is shown in Table 2 below.

Measuring method
Tg, Melting point measurement The method for measuring Tg is outlined. Shimadzu thermal analyzer DSC-60 was used as an apparatus for measuring Tg.
First, about 5 mg of a sample is placed in an aluminum sample container, which is placed on a holder unit and set in an electric furnace. First, after heating from 20 ° C. to 150 ° C. at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, the sample is cooled to room temperature at a temperature rising rate of 10 ° C./min. DSC measurement was performed again by heating to 150 ° C. at a temperature rising rate of 10 ° C./min. Tg was obtained by reading the contact point between the tangent line of the endothermic curve near the Tg and the base line using the DSC-60 analysis system.

  The amount of heat is also calculated simultaneously. For the melting point of WAX, the maximum peak value of the first endothermic peak is read as the melting point.

Particle size distribution measurement method (TA-II type)
The toner particle size distribution can be measured by various methods. In the present invention, the toner particle size distribution was measured using a Coulter counter. That is, a Coulter counter TA-II type (manufactured by Coulter Co.) is used as a measuring device, and an interface (manufactured by Nikka) and a PC9801 personal computer (manufactured by NEC) are connected, and the electrolyte is 1 Prepare 1% NaCl aqueous solution using grade sodium chloride.

  As a measurement method, 0.1 to 5 ml of a surfactant, preferably alkylbenzenesulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. Disperse for 1 to 3 minutes. In another beaker, 100 to 200 ml of an aqueous electrolytic solution is added, and the sample dispersion is added to a predetermined concentration therein, and 2 to 40 μm based on the number using a 100 μm aperture as an aperture by the Coulter Counter TAII type. The particle size distribution of the particles is measured, the volume distribution and the number distribution of particles of 2 to 40 μm are calculated, and the weight-based weight average particle diameter obtained from the volume distribution (D4: the median value of each channel is the representative value of the channel) )

Fine powder content measuring method A flow type particle image analyzer ("FPIA-2100"; manufactured by Sysmex Corporation) is used to measure ultra fine toner, and analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10) is used. And analyzed. Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) is added to a glass 100 ml beaker, and each toner 0.1 to 0 is added. 0.5 g was added and stirred with a microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5000 to 15000 / μl. In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated. If the amount is too small, the toner cannot be sufficiently wetted. It becomes insufficient. Further, the toner addition amount differs from the particle size, and it is necessary to decrease the small particle size and increase the large particle size. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.

Circularity Test Method A measurement method using a flow particle image analyzer will be described below.

  The measurement of toner, toner particles and external additives using a flow particle image analyzer can be performed using, for example, a flow particle image analyzer FPIA-2000 manufactured by Toa Medical Electronics Co., Ltd.

In the measurement, fine dust is removed through a filter. As a result, in ^10-3 water of 10 ⁻³ cm ³ of water having a measurement range (for example, an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm) of 20 particles or less. Add a few drops of a nonionic surfactant (preferably Contaminone N manufactured by Wako Pure Chemical Industries, Ltd.), add 5 mg of a measurement sample, and condition of 20 kHz, 50 W / 10 cm ^{3 with} an ultrasonic dispersing device STM UH-50. in for 1 minute dispersion treatment, further, the sample dispersion particle concentration of the measurement sample subjected to distributed processing 4000-8000 pieces ^{/ 10} -3 cm ³ (as the target particles measuring circle equivalent diameter range) of the total of 5 minutes Is used to measure the particle size distribution of particles having an equivalent circle diameter of 0.60 μm or more and less than 159.21 μm.

  The sample dispersion liquid is passed through a flow path (expanded along the flow direction) of a flat and flat transparent flow cell (thickness: about 200 μm). In order to form an optical path that passes across the thickness of the flow cell, the strobe and the CCD camera are mounted on the flow cell so as to be opposite to each other. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter.

  In about 1 minute, the equivalent circle diameter of 1200 or more particles can be measured, and the number based on the equivalent circle diameter distribution and the ratio (number%) of particles having a prescribed equivalent circle diameter can be measured. As shown in Table 1, the results (frequency% and cumulative%) can be obtained by dividing the range of 0.06-400 μm into 226 channels (divided into 30 channels for one octave). In actual measurement, particles are measured in the range where the equivalent circle diameter is 0.60 μm or more and less than 159.21 μm.

Softening point test method The softening point here refers to the melting temperature in the 1/2 method, and if a decrease of 5 ° C. or more is observed, the effect on the fixing characteristics increases. Moreover, the measuring method of a softening point is as follows. An example of a flow tester for measuring the thermal characteristics of toner is an elevated flow tester CFT500 manufactured by Shimadzu Corporation. The flow curve of this flow tester becomes the data shown in the following figures (a) and (b), from which each temperature can be read. In the figure, Ts is the softening temperature, Tfb is the outflow start temperature, and the melting temperature in the 1/2 method corresponds to the softening point of the present invention.
<< Measurement Conditions >>: Load: 30 kg / cm ² , Temperature rising rate: 3.0 ° C./min, Die diameter: 0.50 mm, Die length: 1.0 mm

上記評価の結果、実施例１、３乃至５、参考例２に係るトナーを用いた画像形成によれば、定着クリーニングローラからの溶けだしによる汚れも見られず、また低温定着性、耐ホットオフセット性、耐熱保存性、流動性が良好であり、得られた画像の解像度や画像濃度も優れていることが分った。

As a result of the evaluation, according to the image formation using the toners according to Examples 1 , 3 to 5 , and Reference Example 2 , no stain due to melting from the fixing cleaning roller was observed, and low temperature fixing property and hot offset resistance were observed. It was found that the heat resistant storage stability and fluidity were good, and the resolution and image density of the obtained image were excellent.

1 is an overall configuration diagram of a fixing device according to the present invention. 2 is a cross-sectional view of a fixing belt. FIG. It is a figure of the fixing device by this invention which has the induction heating part which provided the coil part formed in loop shape. It is a figure which shows the coil part provided so that the front and back of a support roll might be opposed. FIG. 3 is a schematic diagram for explaining a particle structure of an image forming toner in the present invention. It is a schematic block diagram which shows an example of the process cartridge in this invention. It is a schematic block diagram which shows an example. FIG. 6 is a diagram illustrating a temperature distribution in the width direction of the fixing belt. 7 is a cross-sectional view of the upper half of the facing roller, illustrating Embodiment B of the present invention. FIG. It is a figure explaining the effect by Example B.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10 'Fixing device 11 Fixing roller 12 Opposed roller 12a Cylindrical part 12c Center part 12d End part 13 Fixing belt 13a Base material 13b Elastic layer 13c Release layer 13d Base material 14 Induction coil (induction heating means)
DESCRIPTION OF SYMBOLS 15 Nip part 16 Pressure roller 18 Temperature sensor 19 Control apparatus 20 Guide plate 22 Fixing belt 22b Heat generating layer 23 Support roller 24 Induction heating part 25 Coil part 30 Pressure roller 31 Fixing roller 500 Process cartridge 501 Photoconductor 502 Charging means 503 Development Means 504 Cleaning means P Recording paper T Toner

Claims (9)

A method of fixing toner on a recording medium using a fixing device,
The fixing device includes a coil portion for generating a magnetic flux, and the magnetic shunt alloy you heat by the magnetic flux, a fixing belt,
The fixing belt has a base material, an elastic layer and a release layer sequentially laminated,
The magnetic shunt alloy is provided on the side where the base material is provided with respect to the elastic layer,
The toner contains a crystalline polyester and a release agent, has a ratio of a weight average particle diameter to a number average particle diameter of 1.00 to 1.20, and a content of particles having a particle diameter of 2 μm or less is 12 A fixing method characterized in that the fixing method is not more than a number% . Before SL toner chromatography, the content of the crystalline polyester is 5 to 20%, from 2 to 5% the content of the release agent,
The fixing method according to claim 1, wherein the release agent has a melting point of 60 to 90 ° C. The toner fixing method according to claim 1 or 2, characterized in that it further comprises a urea-modified polyester and unmodified polyester. The toner further contains a colorant and has resin fine particles on the surface ,
Before SL fine resin particles, fixing method according to any one of claims 1 to 3, wherein the glass transition point of 50 to 90 ° C.. The toner fixing method according to any one of claims 1 to 4, wherein the weight average particle diameter of Ru 3.0 to 6.0μm der. The toner fixing method according to any one of claims 1 to 5, characterized in that the particle size is the content of particles larger than 8μm is less 2% by volume. The toner fixing method as claimed in any one of claims 1 to 6, characterized in that the particle size is the content of particles smaller than 3μm is 5 vol% or less. The toner fixing method according to any one of claims 1 to 7, characterized in that a polymerized toner.   An image forming method comprising a step of fixing toner onto a recording medium using the fixing method according to claim 1.

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