JP2005266561A - Image forming method and toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method employing a circumferential speed of a heat fixing roll of 200 mm/sec or higher, the method which does not bring about image quality trouble like density irregularities and enables the life of a fixing device to be prolonged and enables the fixing device to be miniaturized and which is satisfactory in terms of fixing defects resulting from miniaturization of the fixing device, offset performance, and an instant-on function, and to provide a toner therefor. <P>SOLUTION: The image forming method has a latent image forming step, a developer layer forming step, a developing step, a transfer step, and a fixing step, wherein toner contains a resin having a number average molecular weight within a certain range and a release agent having a melting point within a fixed range and has 3 to 7μm number average particle size and has ≥0.75 ratio of diameters of 16% and 50% cumulative particles and has ≤1.30 ratio of diameters of 84% and 50% cumulative particles and has SF1 within the range of 115 to 140, and the heat fixing roll has 200 to 500 mm/sec circumferential speed and has 20 to 30 mm external diameter. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method for fixing a toner image formed by an electrophotographic method, an electrostatic recording method or the like, and a toner used at that time.

  Conventionally, in a copying machine using an electrophotographic process, in order to form a permanent image on a recording sheet as a transfer material, it is necessary to fix an unfixed toner image on the recording sheet. A fixing method, a pressure fixing method, and a heat fixing method are known.

  Among these fixing methods, the solvent fixing method has the disadvantage that there are many odors and sanitary problems because the solvent vapor diverges, and the pressure fixing method has a fixing property compared with other fixing methods. However, it is disadvantageous in that the running cost is high because an expensive pressure sensitive toner must be used, and both of them are not widely put into practical use. On the other hand, a heat-fixing method in which toner is melted by heating and fused onto a recording sheet does not have the above-described drawbacks, and is therefore widely used as a fixing method for unfixed toner images.

  As fixing devices based on the heat fixing method, those of a heat fixing roll method, a hot air fixing method, and an oven fixing method are known, and the heat fixing roll method fixing device is more efficient than other heat fixing method fixing devices. Is currently the most widely used because of its high power, low power, high speed, and low risk of flames caused by paper jams.

  The heat fixing roll type fixing device includes a heat fixing roll, a pressure roll arranged to pressurize the heat fixing roll, and a heater arranged inside the heat fixing roll, and an unfixed toner image is formed. The recording sheet is inserted into the nip region between the heat fixing roll and the pressure roll, and the unfixed toner image is fixed.

  In general, a roll in which a release layer for preventing toner on a recording sheet from adhering to the heat fixing roll is formed on the outer peripheral surface of a cylindrical metal core is used as the heat fixing roll. . As a material for forming the release layer, heat-resistant resins such as polytetrafluoroethylene, perfluoroalkyl vinyl ether copolymers and fluorine-based heat-resistant resins represented by tetrafluoroethylene-hexafluoropropylene copolymers In addition, although heat-resistant rubbers typified by silicone rubber and fluororubber are known, high releasability can be obtained without using a release agent such as so-called release oil. Generally, a fluorine-based heat resistant resin is used.

  However, since the fluorine-based heat-resistant resin is hard, when it is used as a release layer, it is difficult to obtain fine adhesion between the heat-fixing roll and the toner layer on the recording paper. It is known that fine density unevenness occurs. On the other hand, when a heat-resistant rubber having flexibility and extensibility is used as a release layer, excellent image quality without such density unevenness can be obtained.

  Further, for example, when a heat fixing roll in which an RTV (room temperature vulcanization) silicone rubber layer is disposed on an LTV (low temperature vulcanization) silicone rubber layer is used, the heat fixing roll is pressed by being pressurized to the pressure roll. Since the surface of the sheet is elastically deformed and the surface is distorted, there is an advantage in that a gap is generated between the heat fixing roll and the recording sheet, and the recording sheet is prevented from being wound around the heat fixing roll. (For example, refer to Patent Document 1).

  However, the releasability of the heat-resistant rubber to the toner itself is not high, and the heat-resistant rubber has a high coefficient of friction and easily wears. Therefore, when the heat-resistant rubber is used for the release layer, the heat fixing roll It is necessary to provide an application means for applying a release agent.

  In order to solve the above problems, a heat fixing roll in which a fluororesin dispersion is applied and fired on the surface of a heat resistant rubber layer is disclosed (for example, see Patent Documents 2 and 3). However, the thickness of the coated and fired film is at most about 2 to 3 μm, and the release layer is easily worn away by continuously using the fixing device, so that there is a problem that the life of the heat fixing roll is short.

  On the other hand, a heat fixing roll in which a heat-resistant rubber layer is covered with a fluororesin tube manufactured in advance is disclosed (for example, see Patent Documents 4 to 7). However, as a fluororesin tube, only a tube having a thickness of about 50 to 100 μm has been obtained so far, and the tube itself is hard, and the fine adhesion between the heat fixing roll and the toner layer is obtained. It was insufficient.

  As described above, the technology for making full use of the heat fixing roll having a heat-resistant rubber layer having excellent density unevenness requires providing a coating means for applying a release agent to the heat fixing roll, Since the device becomes large and the release layer tends to wear out, the life of the heat fixing roll is shortened, the replacement frequency is increased, and a fine adhesion between the heat fixing roll and the toner layer is obtained. However, it was not sufficient in terms of both miniaturization / long life and uneven density.

Further, in order to stabilize toner charging and conveyance for a long period of time, a developer using a titanium compound obtained by a reaction between TiO (OH) ₂ and a silane compound as an additive in a one-component developer is disclosed. (See, for example, Patent Document 8). However, although good results can be obtained with regard to charging and transportability, the toner particle size distribution, shape, molecular weight, and wax physical properties are insufficient, and this alone is not sufficient with respect to fixing property and offset property in high-speed and small-diameter fixing methods. It was.

  In recent years, there has been an increasing demand for miniaturization and high speed of printers and copiers, and instant-on which enables print output immediately after the switch is turned on. There is an urgent need for both fixing performance.

In general, if the diameter of the heat fixing roll is reduced in order to reduce the size of the fixing device, a sufficient fixing nip width can be secured, and sufficient fixing property with the recording paper is insufficient. In addition, when the roll curvature is small and the diameter is high and the speed is high, the wrapping of the recording paper and the shearing force after passing through the nip increase, so that offset is likely to occur, so that the fixing property and offset property are satisfied. Was difficult.
Japanese Patent Laid-Open No. 5-150679 Japanese Patent Laid-Open No. 61-22376 JP 61-248731 A JP-A-57-89785 JP-A-53-144747 Japanese Patent Publication No. 7-349 JP-A-4-42183 Japanese Patent Laid-Open No. 9-304691

  An object of the present invention is to increase the life of a fixing device without causing image quality defects such as density unevenness in an image forming method in which the peripheral speed (process speed) of a heat fixing roll is 200 mm / sec or more, and a printer. An image forming method capable of satisfying all of downsizing of a copying machine, that is, fixing failure, offset performance, and instant-on as a result of downsizing of a fixing unit and downsizing of a fixing unit, and its one To provide toner.

  As a result of intensive studies on the above problems, the present inventors have caused image quality problems such as density unevenness by defining a specific fixing method and specific toner physical properties in an image forming method having a predetermined fixing method. First of all, it satisfies all of the fixing failure, offset performance, and instant-on that accompany the miniaturization of the fuser and the miniaturization of the fuser, which is one of the means, extending the life of the fuser and downsizing the printer and copier The present inventors have found an image forming method that can be used and a method that can realize the toner and have completed the present invention.

That is, the present invention
<1> At least a latent image forming step for forming an electrostatic latent image on the latent image carrier, and a developer layer containing toner on the surface of the developer carrier disposed to face the latent image carrier. A developer layer forming step, a developing step of developing an electrostatic latent image on the surface of the latent image carrier with the developer layer into a toner image, a transfer step of transferring the toner image to the surface of the transfer material, and a transfer material A fixing step of heating and pressure-fixing the toner image on the surface with a heat fixing roll,
The toner includes a resin having a number average molecular weight in the range of 6000 to 15000 and a release agent having a melting point in the range of 80 to 100 ° C., and the toner has a number average particle size in the range of 3 to 7 μm and is cumulative in the particle size distribution. The ratio (D16 / D50) of the 16% diameter (D16) to the 50% cumulative diameter (D50) is 0.75 or more, and the ratio of the 84% cumulative diameter (D84) to the 50% cumulative diameter (D50). (D84 / D50) is 1.30 or less and the shape factor SF1 is in the range of 115 to 140,
The image forming method is characterized in that a peripheral speed of the heat fixing roll is in a range of 200 to 500 mm / sec, and an outer diameter of the heat fixing roll is in a range of 20 to 30 mm.

<2> The image forming method according to <1>, wherein the external additive of the toner contains at least a titanium compound obtained by a reaction of TiO (OH) ₂ and a silane compound.

<3> The core material of the heat fixing roll is iron, the thickness thereof is in the range of 0.1 to 0.5 mm, and the surface layer is covered with a fluororesin tube having a thickness of 15 μm to 35 μm. <1> or <2> The image forming method according to <1>.

<4> The fixing nip pressure formed by the heat fixing roll and the pressure member is in the range of 0.5 to ^2.5 kgf / cm <2>, according to any one of <1> to <3> This is an image forming method.

<5> The toner image on the surface of the transfer material is used in an image forming method including a fixing step of heating and pressure fixing with a heat fixing roll having a peripheral speed in the range of 200 to 500 mm / sec and an outer diameter in the range of 20 to 30 mm. Toner,
The toner includes a resin having a number average molecular weight in the range of 6000 to 15000 and a release agent having a melting point in the range of 80 to 100 ° C., and the toner has a number average particle size in the range of 3 to 7 μm, and is cumulative in the particle size distribution. The ratio (D16 / D50) of the 16% diameter (D16) to the 50% cumulative diameter (D50) is 0.75 or more, and the ratio of the 84% cumulative diameter (D84) to the 50% cumulative diameter (D50). The toner is characterized in that (D84 / D50) is 1.30 or less and the shape factor SF1 is in the range of 115 to 140.

<6> The toner according to <5>, which contains at least a titanium compound obtained by a reaction of TiO (OH) ₂ and a silane compound as an external additive of the toner.

<7> The core material of the heat fixing roll is iron, the thickness thereof is in the range of 0.1 to 0.5 mm, and the surface layer is covered with a fluororesin tube having a thickness of 15 μm to 35 μm. <5> or <6>.

<8> The fixing nip pressure formed by the heat-fixing roll and the pressure member is in a range of 0.5 to ^2.5 kgf / cm ² , and any one of <5> to <7> Toner.

  According to the present invention, the problem in a high-speed and small machine in which the peripheral speed (process speed) of the heat fixing roll is in the range of 200 m to 500 mm / sec and the outer diameter of the heat fixing roll is in the range of 20 to 30 mm is improved. With regard to the deterioration of the fixing property, the deterioration of the winding property / offset property to the roll, and the occurrence of density unevenness due to the high speed condition and the condition using the small diameter heat fixing roll, the fixing property can be obtained by using the toner described in <1>. Improvement, wrapping prevention, and offset prevention. Further, since the toner has a specific particle size distribution and shape factor, density unevenness can be prevented. This can achieve an extended life because an effect can be obtained without having an elastic layer that is disadvantageous from the viewpoint of the life of the heat-fixing roll.

  In addition, by making the roll core material iron and making the thickness thin within the above range, instant-on can be achieved that can shorten the time to reach the predetermined fixing temperature. By setting the pressure within a predetermined range, it is possible to prevent paper wrinkle due to a difference in deflection and pressure distribution.

  Further, by using the toner external additive described in <3> and <4>, offset resistance can be prevented for a long time even in high-speed image formation. Furthermore, by using a fluorine-based resin tube having a specific thickness, the density unevenness is good and the mechanical durability is excellent. Therefore, wear due to high speed and long-term use is reduced, and the life can be extended.

Hereinafter, the contents of the invention will be described in more detail.
The fixing device used in the present invention includes a heat fixing roll, a heater, and a pressure member. As the heat fixing roll, a heat fixing roll in which a fluororesin tube is coated on a cylindrical core metal can be used. In addition, the pressure member has only a heat-resistant elastic layer formed on a cylindrical metal core, a barrier layer that prevents oil penetration on the heat-resistant elastic layer, and a release layer on the barrier layer. A pressure roll, a pad, a belt, or the like on which a heat-resistant elastic body layer having good properties is formed can be used.

  As a material for forming the cored bar, generally, iron having excellent rigidity, stainless steel, aluminum having excellent heat conductivity, or the like is used. In order to shorten the time for the surface temperature to reach a predetermined temperature as a response to the instant-on request, it can be achieved by making it thin. However, a material having excellent rigidity must be selected because of the thin thickness. For this reason, in the present invention, it is desirable to use thin-walled iron as the core material of the heat fixing roll from the viewpoint of achieving both instant-on properties and preventing paper wrinkles due to bending.

  By making the thickness of the iron core material 0.1 to 0.5 mm, it is possible to achieve both surface temperature and rigidity, and more preferably 0.13 to 0.45 mm. When the thickness of the core is less than 0.1 mm, the thermal conductivity is improved, the instant-on property is advantageous, and the fixability is also advantageous from the viewpoint of temperature, but the rigidity tends to be insufficient and the fixing pressure is increased. This is disadvantageous in terms of the fixing property in terms of pressure, and paper wrinkles due to bending when the fixing pressure is sufficiently applied tend to occur. When the thickness of the core material exceeds 0.5 mm, the time for the surface temperature to reach a predetermined temperature tends to be long, and the instant-on property tends to decrease.

  In the case of a pressure roll, the hardness of the heat-resistant elastic layer can be set to an arbitrary value, but as an example, when measured according to JISK6301, it can be set to 20 to 70 degrees.

  Examples of the fluororesin used in the tube include polytetrafluoroethylene (PTFE), perfluoroalkyl vinyl ether copolymer (PFA), and tetrafluoroethylene-hexafluoropropylene copolymer (FEP). Among these, PFA is preferable from the viewpoint of heat resistance and workability. In addition, in order to improve adhesiveness with a core material, the primer process by etching etc. can be given to the inner surface of a tube.

  In the case of a heat fixing roll, the thickness of the tube is preferably 15 μm to 35 μm. If the tube thickness is less than 15 μm, it is easy to wear and the life of the heat-fixing roll tends to be shortened. If it exceeds 35 μm, the surface of the heat-fixing roll tends to become hard and the density unevenness is insufficiently improved. The instant-on property due to the decrease in thermal conductivity may be insufficient. The thickness of the tube is more preferably 20 μm to 30 μm.

  On the other hand, when the pressure roll includes a fluororesin tube, the thickness of the tube can be set to an arbitrary value, but as an example, it can be set in a range of 30 to 50 μm.

  Further, when the pressure roll includes a heat-resistant elastic layer having good releasability as the uppermost layer, examples of the material used for such a heat-resistant elastic layer include fluoro rubber and silicone rubber.

In the present invention, the pressure member is disposed so as to pressurize the heat fixing roll, and the nip pressure with the heat fixing roll at this time is preferably in the range of 0.5 to ^2.5 kgf / cm ² . In the image forming method in which the peripheral speed of the heat fixing roll is 200 mm / sec or more and 500 mm / sec or less as in the present invention and the outer diameter of the heat fixing roll is 20 to 30 mm, paper wrinkles are particularly likely to occur. This range is preferable in terms of both the fixing property and the paper wrinkle. That is, when the nip pressure is less than 0.5 kgf / cm ² , the fixing property with the recording material tends to be insufficient, and when the nip pressure exceeds 2.5 kgf / cm ² , paper wrinkles are likely to occur. A more preferable nip pressure range is 1.0 to 2.0 kgf / cm ² . On the other hand, if the peripheral speed of the heat fixing roll exceeds 500 mm / sec, the fixing time becomes too short and the fixing property is deteriorated.

  In the present invention, in order to improve the releasability on the surface of the heat fixing roll, it is possible to provide an applying means for applying oil to the heat fixing roll. Examples of the oil at this time include dimethyl silicone oil, methylphenyl silicone oil, fluorine-based silicone oil, and fluoropolyether-based fluorine oil.

Moreover, a halogen lamp etc. are used suitably for a heater.
The fixing device used in the present invention having the above-described configuration can be applied to black and white and color printers, copiers, multifunction machines, and the like.

Next, the toner used in the present invention will be described.
The toner used in the present invention is particularly limited by the production method as long as it satisfies the particle size, particle size distribution, shape factor, toner resin molecular weight, and release agent melting point described in the claims. is not. For example, the particles obtained by kneading and pulverizing method, kneading and pulverizing method of kneading, pulverizing, and classifying binder resin, colorant, release agent, and charge control agent, etc., if necessary, mechanical impact force or thermal energy A method of changing the shape by emulsion polymerization of a polymerizable monomer of a binder resin, and a dispersion liquid formed and a dispersion liquid of a colorant, a release agent, and a charge control agent as necessary. Emulsion polymerization aggregation method to obtain toner particles by mixing, agglomeration and heat fusion, a polymerizable monomer for obtaining a binder resin, a colorant, a release agent, and a charge control agent if necessary Suspension in a water-based solvent for polymerization, suspension polymerization, binder resin, colorant, release agent, and if necessary, a charge control agent or the like is suspended in an aqueous solvent for granulation A dissolution suspension method or the like can be used.

  In addition, a known method such as a production method in which the toner obtained by the above method is used as a core and fine particles are further adhered and heat-fused to give a core-shell structure can be used, but from the viewpoint of shape control and particle size distribution control. Suspension polymerization method, emulsion polymerization aggregation method and dissolution suspension method, which are produced in an aqueous solvent, are preferred, and emulsion polymerization aggregation method is particularly preferred.

The toner of the present invention includes a resin having a number average molecular weight in the range of 6000 to 15000 and a release agent having a melting point in the range of 80 to 100 ° C., and the toner has a number average particle diameter (cumulative number 50% diameter) of 3 to 3. In the particle size distribution, the ratio (D16 / D50) of cumulative number 16% diameter (D16) to cumulative number 50% diameter (D50) in the particle size distribution is 0.75 or more, cumulative number 84% diameter (D84) and cumulative The ratio (D84 / D50) to the 50% diameter (D50) is 1.30 or less and the shape factor SF1 is in the range of 115 to 140.
The accumulated number is indicated by accumulation from the small diameter side.

  When the number average particle diameter of the toner is in the range of 3 to 7 μm, it is possible to prevent offset of a halftone portion having a low toner image density and to maintain sufficient fixability. If the number average particle diameter of the toner is less than 3 μm, the toner will sink into the paper fiber, so that a sufficient fixing pressure cannot be applied, and in particular, the fixing property in the halftone portion where the toner image density is low is insufficient. Therefore, the sheet is not sufficiently adhered to the paper and is offset to the heat fixing roll. If the thickness exceeds 7 μm, a large number of voids exist between the toner layers. Therefore, particularly when the peripheral speed (process speed) of the heat-fixing roll is as high as 200 mm / sec or more, a sufficient amount of heat is given to the entire toner. Is insufficient, and the fixing property is insufficient. A more preferable range is 5 to 7 μm.

  Further, in the toner particle size distribution, the ratio (D16 / D50) of the cumulative number 16% diameter (D16) to the cumulative 50% diameter (D50) is 0.75 or more, the cumulative number 84% diameter (D84) and the cumulative number 50%. By setting the ratio (D84 / D50) to the diameter (D50) in the range of 1.30 or less, the particle size distribution becomes sharp, uniform fixing is obtained, and unevenness of the surface is difficult to occur, resulting in uneven density. do not do.

  Since the image before fixing is more uniform due to the individual number particle size of the toner, the distribution of the number particle size is more important than the volume particle size. As a more preferable range, D16 / D50 is 0.80 or more and D84 / D50 is 1.25 or less. Even when a fluororesin tube having a relatively hard surface having a surface layer of 15 μm to 35 μm is used for the surface layer of the heat fixing roll, it has been difficult to fix uniformly with the conventional toner. , The effect can be obtained.

  Further, when the shape factor SF1 is in the range of 115 to 140, the toner has less surface irregularities and is rounded, so there are few voids as unfixed toner, and the amount of fixing heat can be efficiently given, which is advantageous for fixability. Since the toner is easily packed most closely and unevenness is difficult to occur, density unevenness can be reduced. Moreover, since there are few voids, the fracture surface is less likely to occur, and offset resistance is advantageous.

  If the shape factor SF1 is less than 115, the fluidity is too good, and the set fixing temperature of the heat fixing roll becomes high in the high speed process where the peripheral speed of the heat fixing roll is 200 mm / sec or more. The unfixed toner moves due to the generated steam, and the image is disturbed. On the other hand, if the shape factor SF1 is larger than 140, there are many voids as unfixed toner, and the amount of fixing heat cannot be efficiently applied, which is disadvantageous for fixing properties. As a preferable range, the shape factor SF1 is in a range of 120 to 135.

The shape factor SF1 is obtained by taking the toner particles dispersed on the slide glass or the optical microscope image of the toner into a Luzex image analyzer through a video camera, and obtaining the maximum length and projected area of 50 or more toners. Is obtained by calculating the average value.
SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

The number average molecular weight of the resin contained in the toner of the present invention is in the range of 6000 to 15000. However, when the peripheral speed of the heat fixing roll as in the present invention is as high as 200 mm / sec or more, it passes through the fixing nip. Since the time is short, the fixability of conventional toners tends to deteriorate.
When the number average molecular weight is in the range of 6000 to 1500, fixing can be performed at a preferable fixing temperature, and defects at the time of bending of the obtained fixed image can be prevented.

  When the number average molecular weight is less than 6000, the mechanical strength is weak, the image defect when the fixed image is folded is large, the fixing property is disadvantageous, and the offset resistance is disadvantageous because it is easily broken. On the other hand, when the number average molecular weight is larger than 15000, the viscosity at the time of melting becomes too high, so that the melting / penetration into the recording material becomes insufficient at the time of fixing. A more preferable range of the number average molecular weight is 7000 to 12000.

  Examples of the polymer used as the thermoplastic binder resin used in the present invention include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid Esters having a vinyl group such as lauryl, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polyolefins such as ethylene, propylene and butadiene; Or a copolymer obtained by combining two or more thereof, or a mixture thereof, and further, an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin, a non-vinyl condensation resin, or Examples thereof include a mixture of these with the vinyl resin, and a graft polymer obtained when the vinyl monomer is polymerized in the presence of these.

  In the case of vinyl-based monomers, emulsion polymerization and seed polymerization can be performed using an ionic surfactant or the like to create a resin particle dispersion, and in the case of other resins, it is oily and soluble in water If the resin is soluble in a relatively low solvent, the resin is dissolved in those solvents and dispersed in water together with an ionic surfactant or polymer electrolyte in water with a disperser such as a homogenizer, and then heated or decompressed. The resin fine particle dispersion can be prepared by evaporating the solvent.

  Examples of dissociative vinyl monomers include acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, vinyl sulfonic acid, ethyleneimine, vinylpyridine, vinylamine and other polymer acids and polymer base materials. Any of the following monomers can be used, but a polymer acid is preferred because of the ease of polymer formation reaction, and further, acrylic acid, methacrylic acid, maleic acid, cinnamic acid, fumaric acid, etc. A dissociable vinyl monomer having a carboxyl group is preferred for controlling the degree of polymerization and the glass transition point.

  The melting point of the release agent of the toner of the present invention is in the range of 80 to 100 ° C. In particular, in the case of a small-diameter heat fixing roll having a high peripheral speed of 200 mm / sec or more as in the present invention, the recording material ( The toner is likely to be wound around the heat-fixing roll and offset, so even if the amount of heat applied is small, it must be eluted on the surface of the fixing toner image to ensure releasability, and the melting point of the release agent is 100 ° C. The following is required: However, when the melting point of the release agent is lower than 80 ° C., the fixed recording material is discharged from the fixing device particularly when the peripheral speed of the heat fixing roll as in the present invention is used at a high speed of 200 mm / sec or more. When stacked on a discharge tray or the like, the recording material is fused with the release agent because the wax on the surface of the fixed image is sufficiently cooled and solidified. Therefore, the melting point of the release agent needs to be 80 ° C. or higher.

  Examples of mold release agents include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide Plant waxes such as ester wax, carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc .; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax , Minerals such as Fischer-Tropsch wax, petroleum-based waxes, and modified products thereof.

When a titanium compound obtained by the reaction of TiO (OH) ₂ and a silane compound is contained as the toner external additive of the present invention, it is more suitable for the anti-offset property. In particular, a titanium compound having a specific gravity of 2.8 to 3.6 is desirable. In the high speed region where the peripheral speed of the heat fixing roll is 200 mm / sec or more, the speed of the consumed toner is high, and the required level for the change in the charge amount of the developer becomes high. In order to achieve long-term stability of the toner charge amount and sharpness of charge distribution, relatively low resistance external additives such as titania and alumina are generally used in addition to high resistance external additives such as silica. used.

  In particular, in the case of a small-diameter toner having a number average particle diameter of about 3 to 7 μm, in order to improve the charge rising, the addition amount of the titania toner surface must be increased. When the amount of the external additive is large, the offset property is deteriorated particularly in the case of using a release agent in the melting point range defined in the present invention. The reason for this is not clear, but if a large amount of toner external additives are present on the toner surface, the release agent that has oozed out on the toner surface during fixing and the external additive are compatible with each other, increasing the viscosity of the release agent and releasing the release agent. It is considered that the moldability deteriorates and an offset occurs.

  Since ordinary titania has a large specific gravity of about 4, a titanium compound having a specific gravity of 2.8 to 3.6 can reduce the amount of addition even with the same toner surface coverage, thereby improving offset resistance. In addition, since other titania / alumina has more aggregates than the titanium compound, it must be added more than the titanium compound in order to ensure a sufficient toner surface coverage. End up. Therefore, in the case where both are used together, it is supplementarily used, for example, in a small amount in the range of 0.5% or less.

As the titanium compound, a titanium compound produced by a wet method and having a specific gravity of 2.8 to 3.6 is particularly desirable. In general, the production method of titanium oxide by an ordinary wet method is produced through a chemical reaction in a solvent, and can be divided into a sulfuric acid method and a hydrochloric acid method. If the sulfuric acid method is simplified, the following reaction proceeds in a liquid phase, and insoluble TiO (OH) ₂ is produced by hydrolysis.
FeTiO ₃ + 2H ₂ SO ₄ → FeSO ₄ + TiOSO ₄ + 2H ₂ O
TiOSO ₄ + 2H ₂ O → TiO (OH) ₂ + H 2 SO ₄

In the hydrochloric acid method, titanium tetrachloride is produced by chlorination in the same manner as the dry method. Thereafter, it is dissolved in water and hydrolyzed while adding a strong base to produce TiO (OH) ₂ . The following is a simplified example.
TiCl ₄ + H ₂ O → TiOCl ₂ + 2HCl
TiOCl ₂ + 2H ₂ O → TiO (OH) ₂ + 2HCl

  In a normal titanium oxide production process, water washing and filtration are repeated thereafter, and titanium oxide is obtained by firing. Further, after pulverization and pulverization, a treatment such as a silane compound is performed as necessary. However, this conventional production of titanium oxide has a serious drawback in that particles are sintered due to the strength of bonding between Ti in the firing step, and a large number of agglomerates are generated. In order to solve this serious drawback, many contrivances have been made such as strengthening of wet pulverization and treatment agent reaction before drying. However, it is not possible to break up this agglomeration to primary particles. Even if this titanium oxide is applied as a toner additive, even if the toner surface coverage is combined with silica particles, fluidity similar to silica cannot be obtained, and this phenomenon seems to be caused by aggregation of particles, As a result, sensitive material scratches and filming occur.

  Further, titanium oxide treated by a conventional production method has a limit in the amount that can be treated in the treatment of a silane compound. In general, increasing the amount of the silane compound increases the chargeability-imparting ability, but the ability is saturated at a treatment amount of 15 to 20% with respect to the amount of titanium oxide. Therefore, even if the amount of the coupling agent is increased in order to give a high charge, not only high charge cannot be obtained, but also when there is a further increase in aggregated particles due to the reaction between excess coupling agents, and further when added to the toner This leads to a decrease in charging speed, broadening of the charge distribution, and the like. As described above, the conventional titanium oxide is not at a level that can satisfy all of the agglomerated particles, the high charging ability, the slow charging speed, and the charge distribution.

However, the titanium compound in the present invention is produced by preferably reacting and drying TiO (OH) ₂ produced in the above-described wet process with a silane compound. In this case, since the obtained titanium compound does not pass through the firing step of several hundred degrees, there is no strong bond between Ti, so there is no aggregation and the particles can be taken out in a state of almost primary particles. Furthermore, since the titanium compound in the present invention directly reacts TiO (OH) ₂ with the silane compound, the amount that can be treated can be increased. In other words, the conventional treated titanium oxide has a low limit value of the amount of treatment that contributes to the charging ability, but the titanium compound used in the present invention has a high limit value, depending on the particle size of the raw material, In general, the effect of the treatment is up to about 3 times the amount of conventional products (about 50 to 70% with respect to the titanium base). Therefore, the charge of the toner can be controlled by the amount of treatment with the silane compound, and the chargeability that can be imparted can be greatly improved over the conventional titanium oxide.

  Furthermore, since excessive silane compounds are reduced, that is, there is little reaction between silane compounds, high charge can be obtained without sacrificing charging speed and charge distribution even when the processing amount is increased. Furthermore, since the titanium compound has little transfer to the developing sleeve / fixing roll and no transfer of the processing agent, that is, there is little contamination of the sleeve / fixing roll, the toner charging on the developer carrying member and the surface of the fixing roll have a long period of time. The releasability of is not changed. Furthermore, there is no adhesion on the photoconductor, and image quality defects do not occur over a long period of time. This is because the specific gravity is 2.8 to 3.6, which is light compared to other titanium oxides, and the toner surface adheres in a strong manner, so that there is no detachment from the toner surface even for long-term use. This is because there is little migration of the treatment agent due to the small reaction between the silane compounds to be treated.

  That is, when the specific gravity of the titanium compound is smaller than 2.8, the titanium compound is less detached from the toner surface, but the reaction between the processing agents increases, so that the processing agent is easily peeled off from the titanium compound, and the photosensitive member. Low toner charge and offset are likely to occur due to filming on the top and contamination of the sleeve and fixing roll. Further, when the specific gravity of the titanium compound is larger than 3.6, the reaction between the processing agents hardly occurs, so that the processing agent does not peel off, but the titanium compound itself is easily peeled off from the toner, and the photosensitive member / developing sleeve / fixing. It is considered that adhesion to the roll is likely to occur.

In the present invention, the titanium compound used preferably has an average primary particle size of 100 nm or less, preferably in the range of 10 nm to 70 nm.
As the silane compound used in the present invention, any type of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyl Triethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis ( Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxy Run, γ-methacryloxypropyltrimethoxysilane, β- (3.4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxy Examples thereof include propylmethyldiethoxysilane, γ-mercaptopropyltrimethoxysilane, and γ-chloropropyltrimethoxysilane, but the treating agent in the present invention is not limited to these compounds.

Also, the amount of processing varies depending on the primary particle size of TiO (OH) ₂ in bulk, with respect to the general TiO (OH) ₂ in bulk 100 parts by weight of a silane compound amount is 5-80 parts by weight More preferably, it is the range of 10-50 weight part. When the processing amount is less than 5 parts by weight, the function of the silane compound to be processed does not function, and when the processing amount exceeds 80 parts by weight, the excess silane compound is converted to oil and the toner fluidity is reduced. Starts to malfunction. However, the treatment with the silane compound is aimed at imparting high charge to the toner, improving the environmental dependency, improving the toner fluidity, and reducing the interaction with the photoreceptor, and the amount of the treatment is the toner and developer used. It must be appropriately adjusted in consideration of the particle size and the like of the support and the TiO (OH) ₂ base material.

  The amount of the additive (titanium compound) added to the toner varies depending on the toner particle size, developer carrier composition, etc., but is 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the toner. The range is more preferably 0.3 to 1.0 parts by weight. If the amount is less than 0.1 parts by weight, the toner charge rise effect cannot be obtained. If the amount exceeds 2.0 parts by weight, the fixing process causes offset and a decrease in fixing strength, and it is used in full color. In this case, the color formation of the layered base color is hindered due to a decrease in light transmittance, and in the case of magnetic one-component development, the titanium compound (free titanium compound) that does not adhere to the toner can be prevented. The amount increases, contaminates the sleeve and adversely affects charging.

  In addition, toner particles may be externally added for various purposes. In order to reduce adhesion and control charging, it is preferable to add a large-diameter inorganic oxide having a volume average particle size of 20 to 300 nm. These large-diameter inorganic oxide fine particles include silica, titanium oxide, aluminum oxide, magnesium oxide, alumina, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, chromium oxide, antimony trioxide, Fine particles such as magnesium oxide and zirconium oxide are exemplified.

  In particular, in an image requiring high transfer efficiency such as a full-color image, the silica has a true specific gravity in the range of 1.3 to 1.9 and a volume average particle diameter in the range of 80 to 300 nm. Monodispersed spherical silica is preferred. By controlling the true specific gravity to 1.9 or less, peeling from the toner particles can be suppressed. Further, by controlling the true specific gravity to 1.3 or more, aggregation and dispersion can be suppressed. The true specific gravity of the monodispersed spherical silica is more preferably in the range of 1.4 to 1.8.

  When the volume average particle diameter of the monodispersed spherical silica is less than 80 nm, it tends not to work effectively for reducing the non-electrostatic adhesion between the toner and the photoreceptor. In particular, the monodispersed spherical silica is easily embedded in the toner particles due to stress in the developing device, and the effect of improving developability and transferability is likely to be significantly reduced. On the other hand, if it exceeds 300 nm, it will be easy to detach from the toner particles, and it will not work effectively to reduce the non-electrostatic adhesion force, and at the same time, it will easily move to the contact member, causing secondary obstacles such as charging inhibition and image quality defects. It becomes easy to cause. The volume average particle diameter of the monodispersed spherical silica is more preferably in the range of 100 to 200 nm.

  In order to clean toner close to a sphere, it is preferable to add lubricant particles to the toner particles because reducing the frictional force between the toner and the photoreceptor at the blade nip is the key. Lubricant particles include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids, aliphatic higher alcohols, and fatty acid metal salts; low molecular weight polyolefins such as polypropylene, polyethylene, and polybutene; silicones having a softening point upon heating; Aliphatic amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide; plant waxes such as carnauba wax, rice wax, candelilla wax, wood wax, jojoba oil, etc .; like beeswax Animal waxes; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc .; and their modified products can be used, these can be used alone No It may be used in combination.

  Among these, fatty acid metal salts and aliphatic alcohols are particularly preferable. As the fatty acid metal salts, metal salts of fatty acids having 10 to 50 carbon atoms with zinc, aluminum, magnesium, calcium and the like are preferably used. As the aliphatic alcohol, a higher aliphatic alcohol having 16 to 150 carbon atoms or the like is preferably used.

  The volume average particle diameter of the lubricant particles is preferably in the range of 0.1 to 10 μm, and the chemical structure may be pulverized to make the volume average particle diameter uniform. Further, the addition amount to the toner base particles is preferably in the range of 0.05 to 2.0 parts by weight, and preferably in the range of 0.1 to 1.5 parts by weight with respect to 100 parts by weight of the toner particles. More preferred.

  In addition, for the purpose of removing adhered matter and deteriorated matter on the surface of the photoreceptor, inorganic fine particles, organic fine particles, composite fine particles obtained by attaching inorganic fine particles to the organic fine particles, and the like can be added.

  The toner of the present invention can be produced by mixing the toner particles and the external additive with a Henschel mixer, a hybridizer, a V blender or the like. In addition, when the toner particles are produced by a wet method, external addition can be performed by a wet method.

  Examples of colorants and internal additives used in the toner of the present invention include carbon black, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, and watch. Young Red, Permanent Red, Brilliantamine 3B, Brilliantamine 6B, Daypon Oil Red, Pyrazolone Red, Risor Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Various pigments such as phthalocyanine blue, phthalocyanine green, malachite green oxalelate; acridine, xanthene, azo, benzoquinone, azine, anne Various types such as traquinone, thioindico, dioxazine, thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazine, thiazole, xanthene Dyes; and the like, and one or more of these colorants can be used in combination.

  Also, magnetic materials such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese and other metals, alloys, and compounds containing these metals can be used as internal additives, and quaternary ammonium salt compounds, nigrosine-based as charge control agents. Various commonly used charge control agents such as dyes composed of complexes of compounds, aluminum, iron, chromium and the like, and triphenylmethane pigments can be used.

  Examples of the developer used in the present invention include a one-component developer composed only of a toner and a two-component developer composed of a toner and a carrier. A two-component developer excellent in charge maintenance and stability is preferable. The carrier is preferably a carrier coated with a coating resin, and the coating resin may be selected from any resin that can be used in the art as a coating layer for the carrier.

  As the coating resin, as a charge imparting resin for imparting negative chargeability to the toner, a nitrogen-containing resin, for example, an amino-based resin such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, And polystyrene resins such as polyvinyl and polyvinylidene resins, acrylic resins, polymethyl methacrylate resins, styrene acrylic copolymer resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl acetate resins, polyvinyl alcohols. Examples thereof include cellulose resins such as resins, polyvinyl butyral resins, and ethyl cellulose resins.

  Examples of the charge imparting resin for imparting positive chargeability to the toner include polystyrene resins, halogenated olefin resins such as polyvinyl chloride, polyester resins such as polyethylene terephthalate resins and polybutylene terephthalate resins, and polycarbonate resins. Can be mentioned. Further, low surface energy materials for preventing the transfer of the toner component to the carrier include polystyrene resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin. Fluoroter such as copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, terpolymer of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomer A polymer and a silicone resin can be used alone or in combination.

  Examples of the nitrogen-containing resin include acrylic resins including dimethylaminoethyl methacrylate, dimethylacrylamide, acrylonitrile and the like, amino resins including urea, urethane, melamine, guanamine, aniline, amide resin, and urethane resin. These copolymer resins may also be used.

  As the carrier coating resin, two or more of the nitrogen-containing resins may be used in combination. Moreover, you may use combining the said nitrogen containing resin and resin which does not contain nitrogen. The nitrogen-containing resin may be used in the form of fine particles and dispersed in a resin not containing nitrogen. In particular, a urea resin, a urethane resin, a melamine resin, a guanamine resin, and an amide resin are preferable because they have high positive chargeability and high resin hardness, and can suppress a decrease in charge amount due to peeling of the coating resin.

In general, the carrier needs to have an appropriate electric resistance value, and specifically, an electric resistance value in a range of about 10 ⁸ to 10 ¹⁴ Ωcm is required. For example, when the electrical resistance value is as low as 10 ⁶ Ωcm as in the case of an iron powder carrier, the carrier adheres to the image portion of the photoreceptor due to charge injection from the sleeve, or the latent image charge escapes through the carrier, and the latent image This causes problems such as disturbance of images and loss of images. On the other hand, if the insulating resin is coated thickly, the electrical resistance value becomes too high and carrier charges are difficult to leak, resulting in an edged image. This causes a problem of an edge effect that the image density of the image becomes very thin. Therefore, it is preferable to disperse the conductive powder in the resin coating layer in order to adjust the resistance of the carrier.

The carrier resistance is obtained by an ordinary electrode plate electric resistance measurement method in which carrier particles are sandwiched between two electrode plates and a current is measured when a voltage is applied, and is 10 ^3.8 V / cm. Evaluation is based on resistance under an electric field.

The electric resistance of the conductive powder itself is preferably 10 ⁸ Ωcm or less, and more preferably 10 ⁵ Ωcm or less. Specific examples of the conductive powder include metals such as gold, silver, and copper; carbon black; conductive metal oxides such as titanium oxide and zinc oxide; titanium oxide, zinc oxide, aluminum borate, and titanium. Examples thereof include a composite system in which the surface of fine particles such as potassium acid and tin oxide are coated with a conductive metal oxide. Carbon black is particularly preferable from the viewpoints of production stability, cost, and low electrical resistance. The type of carbon black is not particularly limited, but those having a DBP (dibutyl phthalate) oil absorption of 50 to 300 ml / 100 g with good production stability are preferred. The volume average particle diameter of the conductive powder is preferably 0.1 μm or less, and the primary volume average particle diameter is preferably 50 nm or less for dispersion.

Examples of the method for forming the coating resin layer on the surface of the carrier core material include an immersion method in which the powder of the carrier core material is immersed in the coating resin layer forming solution, and the coating resin layer forming solution is used for the carrier core material. Spray method for spraying on the surface, fluidized bed method for spraying the coating resin layer forming solution in a state where the carrier core material is floated by flowing air, mixing the carrier core material and the coating resin layer forming solution in a kneader coater The kneader coater method to remove the coating, and the powder coat method in which the coating resin is finely divided and mixed in the carrier core material and the kneader coater at a temperature equal to or higher than the melting point of the coating resin and cooled to form the coating, particularly the kneader coater method and the powder coating method. Preferably used.
The average film thickness of the resin coating layer formed by the above method is usually in the range of 0.1 to 10 μm, preferably in the range of 0.2 to 5 μm.

  The core material (carrier core material) used for the carrier for developing an electrostatic latent image in the present invention is not particularly limited, and a magnetic metal such as iron, steel, nickel and cobalt, or a magnetic oxide such as ferrite and magnetite, Although glass beads etc. are mentioned, it is desirable that it is a magnetic carrier from a viewpoint of using a magnetic brush method. As a volume average particle diameter of a carrier core material, generally the range of 10-100 micrometers is preferable, and the range of 20-80 micrometers is more preferable.

  The mixing ratio (weight ratio) between the electrophotographic toner of the present invention and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100-30: 100, and 3: 100- A range of about 20: 100 is more preferable.

As described above, the image forming method of the present invention includes a latent image forming step of forming an electrostatic latent image on the surface of the latent image carrier, and a surface of the developer carrier disposed opposite to the latent image carrier. A developer layer forming step of forming a developer layer containing toner, a developing step of developing the electrostatic latent image by the developer layer to form a toner image, and a step of transferring the toner image to the transfer material surface; And a step of melting the toner image transferred on the surface of the transfer material by heating and pressurizing with a heat fixing roll and fixing the toner image on the surface of the recording material. Toner is used.
In the image forming method of the present invention, the process speed is in the range of 200 to 500 mm / sec, and the outer diameter of the heat fixing roll is in the range of 20 to 30 mm.

The latent image forming step is a step of forming an electrostatic latent image by uniformly charging the surface of the latent image carrier with a charging means and then exposing the latent image carrier with a laser optical system or an LED array. It is. As the charging means, a contact-type charger such as corotron and scorotron, and a contact-type charger that charges the surface of the latent image carrier by applying a voltage to a conductive member in contact with the surface of the latent image carrier. Examples of the charger include any charger. However, a contact charging type charger is preferable from the viewpoint that the amount of ozone generated is small, environmentally friendly, and excellent printing durability. In the contact charging type charger, the shape of the conductive member may be any of a brush shape, a blade shape, a pin electrode shape, a roller shape, and the like, but a roller-like member is preferable.
The image forming method of the present invention is not limited at all in the process of forming an electrostatic latent image.

  The developing step of developing using the developer is a method in which the developer carrying member having a developer layer containing at least toner on the surface is brought into contact with or close to the surface of the latent image carrying member. In this step, toner particles are attached to the electrostatic latent image to form a toner image on the surface of the latent image carrier. The development method can be performed using a known method, and examples of the development method using the two-component developer used in the present invention include a cascade method and a magnetic brush method. The development may be a so-called regular development method or a reversal development method, but it is preferable to use a reversal development method. The image forming method of the present invention is not particularly limited with respect to the developing method.

  The transferring step is a step of transferring a toner image formed on the surface of the latent image carrier to a transfer material to form a transfer image. In the case of color image formation, it is preferable that the respective color toners are primarily transferred to an intermediate transfer drum or belt as a transfer material and then secondarily transferred to a recording medium such as paper.

A corotron can be used as a transfer device for transferring a toner image from the photosensitive member to paper or an intermediate transfer member. The corotron is effective as a means for uniformly charging the paper, but in order to give a predetermined charge to the paper as a recording material, a high voltage of several kV must be applied and a high voltage power source is required. In addition, ozone is generated by corona discharge, which causes deterioration of rubber parts and photoconductors. Therefore, contact is made to transfer a toner image onto a sheet by pressing a conductive transfer roll made of an elastic material against an electrostatic charge image carrier. A transfer system is preferred.
In the image forming method of the present invention, the transfer device is not particularly limited.

The fixing step is a step of fixing the toner image transferred on the surface of the recording material with a fixing device. As the fixing device, as described above, a heat fixing device using a heat fixing roll as a fixing medium is used. The fixing temperature is preferably 160 ° C. or higher, and more preferably set to about 180 to 210 ° C.
In the image forming method of the present invention, the fixing method is not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to examples. In the following description, “parts” means “parts by weight” unless otherwise specified.
<Measurement method of each physical property>
Each physical property value of the toner was measured by the following method.
(Toner particle size distribution)
A Coulter Multisizer-II type (manufactured by Beckman Coulter, Inc.) was used as a measuring apparatus, and an ISOTON-II (manufactured by Beckman Coulter, Inc.) was used as an electrolyte.

As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This is added to 100 to 150 ml of the electrolytic solution.
The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 to 60 μm is measured using the Coulter counter TA-II with an aperture diameter of 100 μm. The number particle size distribution was determined. The number of particles to be measured is 50,000.

  For the divided particle size range (channel), the measured particle size distribution is drawn from the small diameter side with respect to the number, and the particle size that becomes 16% cumulative is defined as the cumulative number 16% diameter (D16). The particle size at 50% is defined as the cumulative 50% size (D50, the number average particle size of the toner described above indicates this). Similarly, the particle diameter that is 84% cumulative is defined as the cumulative number 84% diameter (D84). Using these, D16 / D50 and D84 / D50 were determined.

(Toner shape factor)
The toner shape factor SF1 is obtained by taking toner particles dispersed on a slide glass or an optical microscope image of the toner into a Luzex image analyzer (LUZEX III, manufactured by Nireco) through a video camera, and calculating the maximum length of 50 or more toners. The projection area is obtained, calculated by the following formula, and the average value is obtained.
SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

(Molecular weight of resin)
The molecular weight of the resin or the like contained in the toner of the present invention was measured using gel permeation chromatography (GPC). GPC uses HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation), and column uses two TSKgel and SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm). THF (tetrahydrofuran) was used. As experimental conditions, the sample concentration was 0.5 mass%, the flow rate was 0.6 ml / min, the sample injection amount was 10 μl, the measurement temperature was 40 ° C., and the experiment was performed using an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”. The data collection interval in sample analysis was 300 ms.

(Specific gravity of titanium compound)
It measured based on JIS K-0061 and 5-2-1 using a Le Chatelier specific gravity bottle. The operation is as follows. Put about 250 ml of water into the Lecherteria specific gravity bottle, and adjust so that the meniscus is at the position of the scale. When the specific gravity bottle is immersed in a constant temperature water bath and the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy is 0.025 ml). About 100 g of a sample is weighed to the order of 1 mg, and its mass is defined as W. Place the weighed sample in a specific gravity bottle to remove bubbles. The specific gravity bottle is immersed in a constant temperature water bath, the liquid temperature is kept at 20.0 ± 0.2 ° C., and the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy is 0.025 ml). The specific gravity is calculated by the following method.
D = W / (L2-L1)
S = D / 0.9982
here,
D: Sample density (20 ° C.) (g / cm ³ )
S: Specific gravity of the sample (20/20 ° C)
W: Apparent mass of sample (g)
L1: Meniscus reading (20 ° C.) (ml) before placing the sample in the density bottle
L2: Reading of the meniscus after placing the sample in a specific gravity bottle (20 ° C.) (ml)
0.9982: density of water at 20 ° C. (g / cm ³ )

(Melting agent melting point)
The release agent melting point was measured using DSC-7 manufactured by Perkinelmer. The temperature of the detection part of the apparatus was corrected using the melting points of indium and zinc, and the heat of fusion was used to correct the amount of heat. As the sample, an aluminum pan was used, an empty pan was set as a control, the temperature was increased at a rate of 10 ° C./min, and the endothermic peak temperature was taken as the melting point.

<Example 1>
(Production of toner)
-Preparation of resin fine particle dispersion A-
A mixture of 370 parts of styrene, 30 parts of n-butyl acrylate, 8 parts of acrylic acid, and 24 parts of dodecanethiol was dissolved in 6 parts of a nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Co., Ltd.) Anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was emulsion-polymerized in a flask in which 550 parts of ion-exchanged water were dissolved, and 4 parts of ammonium persulfate was added thereto while slowly mixing for 10 minutes. 50 parts of dissolved ion exchange water was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5.5 hours.

  As a result, a resin fine particle dispersion A in which resin particles having a volume average particle diameter of 150 nm, a Tg of 59 ° C., a number average molecular weight (Mn) of 9500, and a weight average molecular weight (Mw) of 32,000 is obtained. .

-Preparation of colorant dispersion (1)-
・ Carbon black (Mogal L: Cabot) 60 parts ・ Nonionic surfactant (Nonipol 400: Sanyo Chemical Co., Ltd.) 6 parts ・ Ion-exchanged water 240 parts

  The above components are mixed, dissolved, stirred for 10 minutes using a homogenizer (Ultra Turrax T50: manufactured by IKA), then dispersed with an optimizer (colorant (carbon) having an average particle size of 250 nm. Black) A colorant dispersant (1) in which particles were dispersed was prepared.

-Preparation of release agent dispersion (1)-
Paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point 85 ° C.) 100 parts Cationic surfactant (Sanisol B50: manufactured by Kao Corporation) 5 parts Ion-exchanged water 240 parts

  The above components are dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA) for 10 minutes, and then dispersed with a pressure discharge homogenizer, and the volume average particle diameter is 550 nm. A release agent dispersion liquid (1) in which release agent particles are dispersed was prepared.

-Production of toner particles A-
・ Resin fine particle dispersion A 234 parts ・ Colorant dispersion (1) 30 parts ・ Releasing agent dispersion (1) 40 parts ・ Polyaluminum hydroxide (Pho2S manufactured by Asada Chemical Co., Ltd.) 0.5 parts ・ Ion exchange water 600 copies

  The above components were mixed and dispersed in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then heated to 55 ° C. while stirring the flask in a heating oil bath. . After holding at 55 ° C. for 40 minutes, it was confirmed that aggregated particles having a number average particle size of 5.3 μm were formed. Thereafter, 26 parts of resin fine particle dispersion A was added to the dispersion containing the aggregated particles, and the temperature of the heating oil bath was maintained at 55 ° C. for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 7.0, the stainless steel flask is sealed, and the stirring is continued to 95 ° C. using a magnetic seal. Heat, adjust pH to 6.0 and hold for 4 hours. After cooling, the toner particles were filtered off, washed four times with ion exchange water, and then lyophilized to obtain toner particles A.

  The number average particle diameter D50 of the toner particles A is 6.3 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.80, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.23, and the shape factor SF1 was 132.

-Production of titanium compound A-
Isobutyltrimethoxysilane equivalent to 40 parts is mixed with 100 parts of TiO (OH) ₂ produced by the above-described method and reacted by applying heat. Thereafter, it was washed with water, filtered, dried at 120 ° C., and soft agglomerated with a pin mill to obtain a titanium compound A having a volume average particle size of 40 nm and a specific gravity of 3.1.

-Preparation of Toner A-
Toner particle A: 100 parts, titanium compound A: 0.8 part, silica (prepared by vapor phase oxidation method, volume average particle size 40 nm, treated with silicone oil) 1.5 parts, higher alcohol pulverized product (volume average particle After adding 0.5 parts (diameter: 8 μm) and blending for 15 minutes at a peripheral speed of 30 m / sec using a 5 liter Henschel mixer, coarse particles are removed using a sieve with a mesh opening of 45 μm, and toner A Was made. The number average particle size, particle size distribution, and shape factor of this toner were the same as those of toner particle A.

(Creation of carrier)
Mn-Mg based ferrite particles (true specific gravity: 4.6 g / cm ³ , volume average particle size: 35 μm, saturation magnetization: 65 emu / g) 100 parts toluene 11 parts diethylaminoethyl methacrylate-styrene-methyl methacrylate copolymer (Copolymerization ratio: 2/20/78, weight average molecular weight: 50000) 2.5 parts carbon black (manufactured by Cabot, R330R, volume average particle size: 25 nm, DBP value: 71 ml / 100 g, resistance: 10 Ωcm or less) 0.15 parts

The above components excluding the ferrite particles and glass beads (volume average particle diameter: 1 mm, equivalent to toluene) were put into a sand mill manufactured by Kansai Paint Co., Ltd., and stirred for 30 minutes at a rotational speed of 1200 rpm to prepare a coating resin layer forming solution. . Next, this coating resin layer forming solution and ferrite particles are put into a vacuum degassing type kneader, and the temperature is maintained at 60 ° C. for 10 minutes. Then, the pressure is reduced and toluene is distilled off to form a coating resin layer. Carrier A was obtained. The thickness of the coating resin layer was 1 μm. The carrier resistance under an electric field of 10 ^3.8 V / cm was 4 × 10 ¹⁴ Ωcm.

(Preparation of developer)
The developer A was obtained by mixing 8 parts of the toner A and 92 parts of carrier A with a V blender for 20 minutes.

(Manufacture of heat fixing roll and pressure roll)
-Heat fixing roll-
The outer periphery of a cylindrical iron core bar having an outer diameter of 25 mm and a thickness of 0.4 mm was coated with a 30 μm thick PFA resin tube to prepare a heat fixing roll.

-Pressure roll-
An HTV silicone rubber layer (hardness according to JIS K6301: 55 degrees) having a thickness of 7 mm was provided on the outer periphery of a cylindrical aluminum core bar having an outer diameter of 26.5 mm to produce a pressure roll.

(Fixing device)
A halogen lamp was lit inside the heat fixing roll, and the surface temperature of the heat fixing roll could be set to 200 ° C. using a temperature sensor and a temperature controller. Next, the spring was adjusted so that the nip pressure applied between the heat fixing roll and the pressure roll was 2.0 kgf / cm ² . The nip pressure is fixed to the pressure roll, and the load applied to both ends of the heat fixing roll (adjusted according to the spring constant and extension length of the spring) is the fixing nip area (nip length formed by the heat fixing roll and the pressure roll x center (Partial fixing nip width).

(Image evaluation device)
The Duplicant 402 manufactured by Fuji Xerox Co., Ltd. was modified and the fixing device was introduced. Further, the peripheral speed of the surface of the photosensitive member and the peripheral speed (process speed) of the heat fixing roll were modified so as to be variable in a range from 150 mm / sec to the upper limit of 300 mm / sec. The peripheral speed of the developing roll surface of the developing device was set to be twice the peripheral speed of the photoreceptor surface.

(Actual machine evaluation)
Developer A was set in the developing unit of the image evaluation apparatus, and fixing evaluation and image quality evaluation were performed as follows. At this time, the process speed was set to 250 mm / sec, and the heat fixing roll was rotated so that the peripheral speed was 250 mm / sec.

-Fixability-
Fuji Xerox Office Supply Company P paper (thick mouth) (basis weight: 78 g / m ² ) A3 printed half-tone image (toner paste amount: 0.35 mg / cm ² ) of A3 Defects were visually judged according to the following criteria.
G1: good, G2: a level at which no streaks can be seen, and no problem, G3: a clear level with image defects.

−Offset−
Fuji Xerox Office Supply Co., Ltd. P paper (thick mouth) (basis weight: 78 g / m ² ) A 3 cm x 2 cm image printed on A3 (toner paste amount: solid 0.6 mg / cm ² , halftone 0.35 mg / cm ^{In 2} ), the temperature of the heat-fixing roll was varied and visually judged according to the following criteria.
G1: No offset, G2: Level where no offset can be seen, and G3: Obviously, offset is a problem level.

-Density unevenness-
Fuji Xerox Office Supply Company Fuji Xerox Office Supply Company P paper (thick mouth) (basis weight: 78 g / m ² ) A 2 cm × 2 cm black solid image (toner paste amount: 0.6 mg / cm ² ) printed on A3 The minute density unevenness was visually determined according to the following criteria.
G1: No unevenness, G2: A level where there is no problem as long as slight unevenness can be seen, and G3: A problem level due to obvious occurrence of unevenness.

-Paper fusion (Fusing of recording material)-
Fuji Xerox Office Supply Co., which is a double-sided coated paper. JD coated 104 paper A3 was continuously double-sided printed with two full-colored black images (toner paste amount: 0.6 mg / cm ² ), discharged from the fixing device and placed in the discharge tray. The fusion level between the sheets of the print samples stacked one by one was determined as follows according to the tactile sensation when the sheets were opened one by one.
G1: No fusion, G2: Level of no problem with slight fusion, G3: Obvious level of occurrence of fusion.

-Image disturbance-
Fuji Xerox Office Supply, Inc. P paper (thick mouth) (basis weight: 78 g / m ² ) A3 on a full-surface grid pattern composed of 1 cm x 1 cm square line image units, and visually observe the toner scattering level of the line image The determination was as follows.
G1: No splattering, G2: Level with no problem as long as splattering is slightly visible, G3: Level of problem with obvious splattering.

-Wrinkle paper-
Black solid images (toner amount: 0.6mg / cm ²⁾ of 2 cm × 2 cm was printed on Fuji Xerox Office Supply Co. P paper A3, as it follows paper wrinkles of the samples vertical feeding 1000 sheets continuously running visually Judged.
G1: No wrinkle generation, G2: slight wrinkle level with no problem, G3: clear wrinkle generation level.

-Instant-on-
In an environment of 25 ° C. and 50% RH, the time from when the fixing device surface temperature reached room temperature until it reached the fixing set temperature (200 ° C.) after turning on the power was determined to be instant-on and determined as follows.
G1: Pretty good at less than 5 to 10 seconds, G2: Good at 10 to less than 15 seconds, satisfactory level, G3: Problem level at 15 seconds or more.

-Heat fixing roll life-
A fixing off-line idle bench was created, and a life test was carried out in an environment of 25 ° C. and 50% RH at a heat fixing roll surface temperature (200 ° C.) at a roll surface speed of 250 mm / sec. The level of scratches and wrinkles on the surface of the fixing roll corresponding to 100,000 printed sheets was visually determined as follows.
G1: Scratches / wrinkles but no problem in image quality G2: Image quality effects due to scratches / wrinkles are observed, but the problem level is small, G3: problem level.
The results are shown in Table 3.

  In the following Examples 2 to 16 and Comparative Examples 1 to 18, the prototype conditions and the like were changed as shown in Tables 1 and 2 on the basis of Example 1 (details will be described later), and the same as Example 1 The evaluation was conducted.

<Example 2>
Toner particles were prepared by using the same components as in Example 1 and mixing and dispersing in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then in a heating oil bath. The interior was heated to 40 ° C. with stirring. After maintaining at 40 ° C. for 30 minutes, 36 parts of resin fine particle dispersion A was added to the dispersion containing the aggregate particles, and then the temperature of the heating oil bath was maintained at 55 ° C. for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 7.0, the stainless steel flask is sealed and heated to 95 ° C. while continuing to stir using a magnetic seal. The pH was adjusted to 6.7 and held for 4 hours. After cooling, the toner particles were filtered off, washed four times with ion exchange water, and then lyophilized to obtain toner particles B.

  The number average particle diameter D50 of the toner particles B is 3.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.85, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.18, and the shape factor SF1 was 129.

Example 1 except that 100 parts of the toner particles B are replaced with 1.5 parts of titanium compound A and 2.0 parts of silica (prepared by vapor phase oxidation method, volume average particle size 40 nm, silicone oil treatment). Similarly, toner B was prepared and evaluated.
The results are shown in Table 3.

<Example 3>
Toner particles were prepared by using the same components as in Example 1 and mixing and dispersing in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then in a heating oil bath. The interior was heated to 55 ° C. with stirring. After maintaining at 55 ° C. for 80 minutes, 20 parts of the resin fine particle dispersion A was added to the dispersion containing the aggregated particles, and then the temperature of the heating oil bath was maintained at 55 ° C. for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 7.0, the stainless steel flask is sealed and heated to 95 ° C. while continuing to stir using a magnetic seal. The pH was adjusted to 6.0 and held for 4 hours. After cooling, the toner particles were filtered off, washed four times with ion exchange water, and then lyophilized to obtain toner particles C.

  The number average particle diameter D50 of the toner particles C is 7.0 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.80, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.24, and the shape factor SF1 was 133.

  Example 1 except that 100 parts of the toner particles C are changed to 0.75 parts of the titanium compound A and 1.2 parts of silica (prepared by vapor phase oxidation method, volume average particle size 40 nm, silicone oil treatment). Similarly, toner C was prepared and evaluated. The results are shown in Table 3.

<Example 4>
Toner particles were prepared by using 0.4 parts of polyaluminum hydroxide (Ahoda Chemical Co., Ltd., Paho2S) and 800 parts of ion-exchanged water, and adjusting the pH to 6.0 and maintaining for 4 hours. Was adjusted to 6.0 and held for 3 hours "to obtain toner particles D in the same manner as in Example 1.

  The number average particle diameter D50 of the toner particles D is 6.5 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.75, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.30, and the shape factor SF1 was 140. Using this toner particle D, a toner D was prepared in the same manner as in Example 1 and evaluated. The results are shown in Table 3.

<Example 5>
The toner particles were prepared in the same manner as in Example 1 except that “the pH was adjusted to 6.0 and held for 4 hours” was changed to “the pH was adjusted to 4.5 and held for 5 hours”. Toner particles E were obtained.

  The number average particle diameter D50 of the toner particles E is 6.1 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.81, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.22, and the shape factor SF1 was 115. Using this toner particle E, toner E was produced in the same manner as in Example 1 and evaluated. The results are shown in Table 3.

<Example 6>
In the preparation of the resin fine particle dispersion A of Example 1, dodecanethiol was changed from 24 parts to 28 parts, the oil bath heating temperature was changed from 70 ° C. to 60 ° C., and the emulsion polymerization time was changed from 5.5 hours to 4.5 hours. Resin fine particle dispersion B was prepared in the same manner except that it was changed to.

  As a result, a resin fine particle dispersion B in which resin particles having a volume average particle size of 120 nm, a Tg of 57 ° C., a number average molecular weight (Mn) of 6000, and a weight average molecular weight (Mw) of 20000 is dispersed is obtained. .

Toner particles F were obtained in the same manner as in Example 1 except that the resin fine particle dispersion A in Example 1 was changed to the resin fine particle dispersion B.
The number average particle diameter D50 of the toner particles F is 6.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.80, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.24, and the shape factor SF1 was 131. A toner F was prepared and evaluated in the same manner as in Example 1 except that this toner particle F was used. The results are shown in Table 3.

<Example 7>
In the preparation of the release agent dispersion (1) of Example 1, paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C.) was converted to polyethylene wax (PW500: manufactured by Toyo Petrolite Co., melting point: 80 ° C.). The toner particles G were obtained in the same manner as in Example 1 except for the above.

The number average particle diameter D50 of the toner particles G is 6.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.81, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.23, and the shape factor SF1 was 131. Toner G was prepared and evaluated in the same manner as in Example 1 except that toner particles G were used.
The results are shown in Table 3.

<Example 8>
In the preparation of the resin fine particle dispersion A of Example 1, dodecanethiol was changed from 24 parts to 18 parts, the oil bath heating temperature was changed from 70 ° C. to 80 ° C., and the emulsion polymerization time was changed from 5.5 hours to 7.5 hours. Resin fine particle dispersion C was obtained in the same manner except that

  As a result, a resin fine particle dispersion C in which resin particles having a volume average particle diameter of 140 nm, a Tg of 60 ° C., a number average molecular weight (Mn) of 15000, and a weight average molecular weight (Mw) of 48000 was obtained. .

Toner particles H were obtained in the same manner as in Example 1 except that the resin fine particle dispersion A in Example 1 was changed to the resin fine particle dispersion C.
The number average particle diameter D50 of the toner particles H is 6.1 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.78, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.25, and the shape factor SF1 was 134. A toner H was prepared and evaluated in the same manner as in Example 1 except that the toner particles H were used.
The results are shown in Table 3.

<Example 9>
In the preparation of the release agent dispersion (1) of Example 1, paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C.) was converted to polyethylene wax (PW725: manufactured by Toyo Petrolite Co., Ltd., melting point: 101 ° C.). The toner particles I were obtained in the same manner as in Example 1 except for the above.

The number average particle diameter D50 of the toner particles I is 6.3 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.80, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.23, and the shape factor SF1 was 132. Toner I was prepared and evaluated in the same manner as in Example 1 except that this toner particle I was used.
The results are shown in Table 3.

<Example 10>
The outer diameter of the heat fixing roll of Example 1 is 25 mm to 20 mm, the core material thickness of the heat fixing roll is 0.4 mm to 0.5 mm, and the fixing nip pressure is 2.0 kgf / cm ² to 2.5 kgf / cm ^2. Evaluation was carried out in the same manner as in Example 1 except that.
The results are shown in Table 3.

<Example 11>
The outer diameter of the heat fixing roll of Example 1 is 25 mm to 20 mm, the core material thickness of the heat fixing roll is 0.4 mm to 0.1 mm, and the fixing nip pressure is 2.0 kgf / cm ² to 0.5 kgf / cm ^2. Evaluation was carried out in the same manner as in Example 1 except that.
The results are shown in Table 3.

<Example 12>
Evaluation was performed in the same manner as in Example 1 except that the thickness of the surface layer of the heat fixing roll of Example 1 was changed from 30 μm to 15 μm.
The results are shown in Table 3.

<Example 13>
In Example 1, except that the fixing nip pressure was changed from 2.0 kgf / cm ² to 0.5 kgf / cm ² , it was prepared and evaluated in the same manner as in Example 1.
The results are shown in Table 3.

<Example 14>
Evaluation was performed in the same manner as in Example 1 except that the thickness of the surface layer of the heat fixing roll of Example 1 was changed from 30 μm to 35 μm.
The results are shown in Table 3.

<Example 15>
In Example 1, evaluation was performed in the same manner as in Example 1 except that the process speed such as the peripheral speed of the heat fixing roll and the peripheral speed of the photosensitive member was changed from 250 mm / sec to 200 mm / sec.
The results are shown in Table 3.

<Example 16>
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the process speed such as the peripheral speed of the heat fixing roll and the peripheral speed of the photosensitive member was changed from 250 mm / sec to 300 mm / sec.
The results are shown in Table 3.

<Comparative Example 1>
Toner particles were prepared by using the same components as in Example 1 and mixing and dispersing in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then in a heating oil bath. The interior was heated to 40 ° C. with stirring. After maintaining at 35 ° C. for 30 minutes, 35 parts of the resin fine particle dispersion A was added to the dispersion containing the aggregated particles, and then the temperature of the heating oil bath was maintained at 55 ° C. for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 7.0, the stainless steel flask is sealed and heated to 95 ° C. while continuing to stir using a magnetic seal. The pH was adjusted to 6.9 and held for 4 hours. After cooling, the toner particles were filtered off, washed four times with ion exchange water, and then lyophilized to obtain toner mother particles J.

  The number average particle diameter D50 of the toner particles J is 2.5 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.85, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.17, and the shape factor SF1 was 128.

Example 1 except that 100 parts of the toner particles J were changed to 1.7 parts of titanium compound A and 2.2 parts of silica (prepared by vapor phase oxidation method, volume average particle size 40 nm, silicone oil treatment). Similarly, toner J was prepared and evaluated.
The results are shown in Table 4.

<Comparative example 2>
Toner particles were prepared by using the same components as in Example 1 and mixing and dispersing in a round stainless steel flask using a homogenizer (Ultra Turrax T50: manufactured by IKA), and then in a heating oil bath. The interior was heated to 55 ° C. with stirring. After maintaining at 55 ° C. for 120 minutes, 16 parts of the resin fine particle dispersion A was added to the dispersion containing the aggregated particles, and then the temperature of the heating oil bath was maintained at 55 ° C. for 30 minutes. After adding 1N sodium hydroxide to the dispersion containing the aggregated particles and adjusting the pH of the system to 7.0, the stainless steel flask is sealed and heated to 95 ° C. while continuing to stir using a magnetic seal. The pH was adjusted to 6.0 and held for 4 hours. After cooling, the toner particles were filtered off, washed four times with ion exchange water, and then freeze-dried to obtain toner mother particles K.

  The number average particle diameter D50 of the toner particles K is 7.7 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.79, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.25, and the shape factor SF1 was 134.

Example 1 except that 100 parts of the toner particles K are changed to 0.7 parts of titanium compound A and 1.1 parts of silica (prepared by vapor phase oxidation method, volume average particle size 40 nm, silicone oil treatment). Similarly, a toner K was prepared and evaluated.
The results are shown in Table 4.

<Comparative Example 3>
The toner particles were prepared by using 0.35 parts of polyaluminum hydroxide (Ahoda Chemical Co., Paho2S) and 800 parts of ion-exchanged water, and adjusting the pH to 6.0 and maintaining for 4 hours. Was adjusted to 6.0 and held for 2.5 hours "to obtain toner particles L in the same manner as in Example 1.

The number average particle diameter D50 of the toner particles L is 6.8 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.72, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.33, and the shape factor SF1 was 142. Using this toner particle L, a toner L was prepared and evaluated in the same manner as in Example 1.
The results are shown in Table 4.

<Comparative example 4>
The toner particles were prepared in the same manner as in Example 1 except that “the pH was adjusted to 6.0 and held for 4 hours” was changed to “the pH was adjusted to 4.0 and held for 5.5 hours”. Thus, toner particles M were obtained.

The number average particle diameter D50 of the toner particles M is 6.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.81, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.22, and the shape factor SF1 was 110. Using this toner particle M, a toner M was prepared in the same manner as in Example 1 and evaluated.
The results are shown in Table 4.

<Comparative Example 5>
In the preparation of the resin fine particle dispersion A of Example 1, dodecanethiol was changed from 24 parts to 27 parts, the oil bath heating temperature was changed from 70 ° C. to 55 ° C., and the emulsion polymerization time was changed from 5.5 hours to 4.0 hours. A resin fine particle dispersion D was prepared in the same manner except that it was changed to.

  As a result, a resin fine particle dispersion D in which resin particles having a volume average particle size of 115 nm, a Tg of 57 ° C., a number average molecular weight (Mn) of 5500, and a weight average molecular weight (Mw) of 18500 is obtained. .

Toner particles N were obtained in the same manner as in Example 1 except that the resin fine particle dispersion A in Example 1 was changed to the resin fine particle dispersion D.
The number average particle diameter D50 of the toner particles N is 6.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.80, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.25, and the shape factor SF1 was 130. Toner N was prepared and evaluated in the same manner as in Example 1 except that the toner particles N were used.
The results are shown in Table 4.

<Comparative Example 6>
In the preparation of the resin fine particle dispersion A of Example 1, dodecanethiol was changed from 24 parts to 16 parts, the oil bath heating temperature was changed from 70 ° C. to 85 ° C., and the emulsion polymerization time was changed from 5.5 hours to 8.5 hours. A resin fine particle dispersion E was prepared in the same manner except that it was changed to.

  As a result, a resin fine particle dispersion E in which resin particles having a volume average particle diameter of 145 nm, a Tg of 61 ° C., a number average molecular weight (Mn) of 16500, and a weight average molecular weight (Mw) of 50,000 was dispersed was obtained. .

Toner particles O were obtained in the same manner as in Example 1 except that the resin fine particle dispersion A in Example 1 was changed to the resin fine particle dispersion E.
The number average particle diameter D50 of the toner particles O is 6.0 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.76, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.24, and the shape factor SF1 was 135. A toner O was prepared and evaluated in the same manner as in Example 1 except that this toner particle O was used.
The results are shown in Table 4.

<Comparative Example 7>
In the preparation of the release agent dispersion liquid (1) of Example 1, paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C.) was paraffin wax (HNP9: manufactured by Nippon Seiki Co., Ltd., melting point): The toner particles P were obtained in the same manner as in Example 1 except that the temperature was changed to 76.degree.

The number average particle diameter D50 of the toner particles P is 6.2 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.81, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.23, and the shape factor SF1 was 130. Toner P was prepared and evaluated in the same manner as in Example 1 except that toner particles P were used.
The results are shown in Table 4.

<Comparative Example 8>
In the preparation of the release agent dispersion (1) of Example 1, paraffin wax (HNP0190: manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C.) was converted to polyethylene wax (PW850: manufactured by Toyo Petrolite Co., Ltd., melting point: 106 ° C. The toner particles Q were obtained in the same manner as in Example 1 except for the above.

The number average particle diameter D50 of the toner particles Q is 6.3 μm, the ratio of the cumulative number 16% diameter to the cumulative number 50% diameter (D16 / D50) is 0.81, and the ratio of the cumulative number 84% diameter to the cumulative 50% diameter ( D84 / D50) was 1.23, and the shape factor SF1 was 133. Toner Q was prepared and evaluated in the same manner as in Example 1 except that toner particle Q was used.
The results are shown in Table 4.

<Comparative Example 9>
The outer diameter of the heat-fixing roll of Example 1 and 15mm from 25 mm, in addition to the fixing nip pressure from 2.0 kgf / cm ² and 2.5 kgf / cm ² was evaluated in the same manner as in Example 1.
The results are shown in Table 4.

<Comparative Example 10>
Evaluation was performed in the same manner as in Example 1 except that the outer diameter of the heat fixing roll of Example 1 was changed from 25 mm to 35 mm.
The results are shown in Table 4.

<Comparative Example 11>
Toner R in Example 1 except that 1.8 parts of rutile type titanium oxide B (volume average particle size 20 nm, n-decyltrimethoxysilane treatment) was added in place of titanium compound A in the same manner as in Example 1. Was made. Other conditions were also evaluated in the same manner as in Example 1.
The results are shown in Table 4.

<Comparative Example 12>
Evaluation was performed in the same manner as in Example 1 except that the core material of the heat fixing roll in Example 1 was changed to aluminum and the fixing nip pressure was changed from 2.0 kgf / cm ² to 0.5 kgf / cm ² .
The results are shown in Table 4.

<Comparative Example 13>
In Example 1, changing the core material thickness of the heat-fixing roll from 0.4mm to 0.08 mm, except that the fixing nip pressure from 2.0 kgf / cm ² and 0.3 kgf / cm ² is in the same manner as in Example 1 The evaluation was conducted.
The results are shown in Table 4.

<Comparative example 14>
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the core material thickness of the heat fixing roll was changed from 0.4 mm to 0.6 mm.
The results are shown in Table 4.

<Comparative Example 15>
Evaluation was performed in the same manner as in Example 1 except that the thickness of the surface layer of the heat fixing roll of Example 1 was changed from 30 μm to 38 μm.
The results are shown in Table 4.

<Comparative Example 16>
Evaluation was performed in the same manner as in Example 1 except that the thickness of the surface layer of the heat fixing roll of Example 1 was changed from 30 μm to 12 μm.
The results are shown in Table 4.

<Comparative Example 17>
In Example 1, except that the fixing nip pressure from 2.0 kgf / cm ² and 0.35kgf / cm ² was evaluated in the same manner as in Example 1.
The results are shown in Table 4.

<Comparative Example 18>
In Example 1, except that the fixing nip pressure from 2.0 kgf / cm ² and 3.0 kgf / cm ² was evaluated in the same manner as in Example 1.
The results are shown in Table 4.

  As shown in the examples and comparative examples, in the image forming method in which the process speed and the peripheral speed of the heat-fixing roll are 200 mm / sec or more and the diameter of the heat-fixing roll is 20 mm to 30 mm, the toner number particle size is in a specific range. Thus, there are no problems with the fixing property and the offset property, and there is no image quality problem such as density unevenness because the toner particle size distribution is in a specific range. Furthermore, because the toner shape factor is in a specific range, there are no image quality problems such as fixing property, offset property, density unevenness, and image disturbance, and the toner number average molecular weight is in a specific range, so that the fixing property is fixed. Also, image quality defects such as offset were not caused.

  In addition, because the melting point of the wax is in a specific range, it is possible to prevent fusing of the recording material while ensuring the offset property, and the offset property can be improved by using a specific titanium compound, and iron is used as the core material of the heat fixing roll. By using a specific thickness, paper wrinkles and instant-on properties are satisfied, and by covering the surface layer of the heat fixing roll with a specific material and thickness, the life of the fixing device and instant-on properties are satisfied. It was found that paper wrinkles and fixability can be satisfied by using a specific fixing nip pressure without causing image quality defects such as density unevenness.

  Furthermore, depending on these specific toner, fixing device, and fixing conditions, downsizing of the printer and copying machine, that is, one of the means, downsizing of the fixing device (in this region, the diameter of the heat fixing roll is 35 to 50 mm). However, according to the present invention, it is possible to satisfy the fixing performance of 20 to 30 mm.

Claims (2)

At least a latent image forming step for forming an electrostatic latent image on the latent image carrier, and a developer layer for forming a developer layer containing toner on the surface of the developer carrier disposed to face the latent image carrier Forming step, developing step of developing an electrostatic latent image on the surface of the latent image carrier with the developer layer to form a toner image, transfer step of transferring the toner image to the surface of the transfer material, and toner on the surface of the transfer material A fixing step of heating and pressure-fixing the image with a heat fixing roll,
The toner includes a resin having a number average molecular weight in the range of 6000 to 15000 and a release agent having a melting point in the range of 80 to 100 ° C. The ratio (D16 / D50) of the 16% diameter (D16) to the 50% cumulative diameter (D50) is 0.75 or more, and the ratio of the 84% cumulative diameter (D84) to the 50% cumulative diameter (D50). (D84 / D50) is 1.30 or less and the shape factor SF1 is in the range of 115 to 140,
An image forming method, wherein a peripheral speed of the heat fixing roll is in a range of 200 to 500 mm / sec, and an outer diameter of the heat fixing roll is in a range of 20 to 30 mm. A toner used in an image forming method including a fixing step in which a toner image on the surface of a transfer material is heated and pressure-fixed by a heat fixing roll having a peripheral speed in a range of 200 to 500 mm / sec and an outer diameter in a range of 20 to 30 mm. There,
The toner includes a resin having a number average molecular weight in the range of 6000 to 15000 and a release agent having a melting point in the range of 80 to 100 ° C., and the toner has a number average particle size in the range of 3 to 7 μm, and is cumulative in the particle size distribution. The ratio (D16 / D50) of the 16% diameter (D16) to the 50% cumulative diameter (D50) is 0.75 or more, and the ratio of the 84% cumulative diameter (D84) to the 50% cumulative diameter (D50). A toner having (D84 / D50) of 1.30 or less and a shape factor SF1 in a range of 115 to 140.