JP4821767B2 - Image forming method and image forming apparatus - Google Patents

Description

  The present invention relates to an image forming method and an image forming apparatus.

In recent years, copiers and printers using an electrophotographic system have been desired to further improve image quality and extend the life of members in addition to energy saving and productivity improvement.
In electrophotographic and electrostatic recording electrostatic printing methods, etc., an electrostatic latent image formed on a latent image holding member composed of a photoconductive photoreceptor or dielectric is developed using toner. To do. Then, the developed image is transferred to a sheet (transfer object), and the transferred image is fixed on the sheet by a fixing device. As a toner fixing method, a heat roll fixing method is widely adopted because of high thermal efficiency and high-speed fixing. In the heat roll fixing method, a sheet carrying an unfixed transfer image is sandwiched between contact portions formed by a fixing roll (fixing member) provided with a heat source and a pressure roll (pressure member) pressed against the fixing roll. The image is heated and melted and pressed to fix it on the paper.

  The fixing efficiency is determined by how quickly the temperature of the toner is raised to the softening point of the resin. Therefore, in order to increase the fixing efficiency, a low-softening resin having a low softening point is contained in the toner binder resin.

  As a technique for improving the releasability of the fixing roll, a fixing roll coated with PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) is shown (for example, see Patent Document 1). Further, a fixing roll coated with PFA in which a conductive substance is dispersed is shown (for example, see Patent Document 2). Furthermore, a fixing roll coated with PFA containing magnesium oxide is shown (for example, see Patent Document 3).

Further, as a toner technology relating to release, there is disclosed a technology for maintaining the release property of the fixing device surface material by imparting elasticity by designing the molecular weight of a resin or releasing effect by wax.
JP-A-6-167900 JP-A-6-167901 JP-A-10-161455

  An object of the present invention is to provide an image forming method and an image forming apparatus capable of extending the life of a fixing member without causing an offset.

The above-mentioned subject is achieved by the following present invention. That is, the present invention
<1> An electrostatic latent image forming step for forming an electrostatic latent image on the latent image holding member, and developing the electrostatic latent image formed on the latent image holding member as a developed image with a developer containing toner. A developing step, a transfer step of transferring the developed image formed on the latent image holding member onto the transfer member, and a fixing step of fixing the transfer image transferred onto the transfer member, The fixing step uses a fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle diameter of 1 μm or less is dispersed and a pressure member to transfer a transfer image transferred onto the transfer target. The toner has a tan δ peak in a range of 40 ° C. or higher and 70 ° C. or lower and a peak value of less than 2.0 in the dynamic viscoelastic temperature dependency measurement. This is a featured image forming method.

<2> The image forming method according to <1>, wherein the wear-resistant additive is carbon black or silicon carbide.
<3> The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0.15 mm or more and less than 4 mm, and the toner has a G ″ of = 100000 Pa in a dynamic viscoelastic temperature dependency measurement. The image forming method according to <1> or <2>, wherein the tan δ value at temperature is 1.7 or more and less than 3.5.

<4> The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0 mm or more and less than 0.15 mm, and the toner has a G ″ of = 100000 Pa in a dynamic viscoelastic temperature dependency measurement. The image forming method according to <1> or <2>, wherein the tan δ value at temperature is 0.5 or more and less than 1.7.

<5> A latent image holding member, electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member, and developing the electrostatic latent image formed on the latent image holding member with toner A developing unit that develops a developed image with an agent, a transfer unit that transfers the developed image formed on the latent image holding member onto the transfer target, and a fixing that fixes the transfer image transferred onto the transfer target. A fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle diameter of 1 μm or less is dispersed, and a pressure member, and the toner has dynamic viscoelasticity. In the temperature dependency measurement, the image forming apparatus is characterized in that a peak of tan δ exists in a range of 40 ° C. or higher and 70 ° C. or lower and the peak value is less than 2.0.
<6> The image forming apparatus according to <5>, wherein the wear-resistant additive is carbon black or silicon carbide.

<7> The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0.15 mm or more and less than 4 mm, and the toner has a G ″ of = 100000 Pa in a dynamic viscoelastic temperature dependency measurement. The image forming apparatus according to <5> or <6>, wherein the tan δ value at temperature is 1.7 or more and less than 3.5.

<8> The fixing member surface layer is formed on a rubber elastic layer having a thickness of 0 mm or more and less than 0.15 mm, and the toner is measured at a temperature at which G ″ is 100000 Pa in dynamic viscoelastic temperature dependency measurement. The image forming apparatus according to <5> or <6>, wherein the tan δ value is 0.5 or more and less than 1.7.

According to the first aspect of the present invention, it is possible to provide an image forming method capable of extending the life of the fixing member without causing an offset as compared with the case where the present configuration is not provided.
According to the second aspect of the present invention, the effect of prolonging the life of the fixing member without causing an offset becomes more prominent than when the present configuration is not provided.

According to the third aspect of the present invention, it is possible to obtain a color that is preferable as a color image as compared with the case where the present configuration is not provided.
According to the fourth aspect of the present invention, a preferable black image can be obtained as compared with the case where this configuration is not provided.

According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus capable of extending the life of the fixing member without causing an offset as compared with the case where the present configuration is not provided.
According to the sixth aspect of the present invention, the effect of prolonging the life of the fixing member without generating an offset becomes more significant than when the present configuration is not provided.

According to the seventh aspect of the present invention, it is possible to obtain a color that is preferable as a color image as compared with the case where the present configuration is not provided.
According to the eighth aspect of the invention, a preferable black image can be obtained as compared with the case where the present configuration is not provided.

  The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on a latent image holding member, and the electrostatic latent image formed on the latent image holding member by a developer containing toner. A developing step for developing as a developed image, a transferring step for transferring the developed image formed on the latent image holding member onto the transferred member, and a fixing step for fixing the transferred image transferred onto the transferred member. The fixing step uses a fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle diameter of 1 μm or less is dispersed and a pressure member, and transfers the image onto the transfer target. In the step of fixing the transferred image, the toner has a tan δ peak in the range of 40 ° C. or higher and 70 ° C. or lower in the dynamic viscoelastic temperature dependency measurement, and the peak value is 2.0. It is characterized by being less than.

  Further, the image forming apparatus of the present invention includes a latent image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the latent image holding member, and an electrostatic image formed on the latent image holding member. A developing unit that develops the latent image as a developed image with a developer containing toner, a transfer unit that transfers the developed image formed on the latent image holding member onto the transfer target, and a transfer unit that is transferred onto the transfer target. Fixing means for fixing the transferred image, and the fixing means includes a fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle size of 1 μm or less is dispersed, and a pressure member, The toner has a tan δ peak in a range of 40 ° C. or higher and 70 ° C. or lower and a peak value of less than 2.0 in dynamic viscoelastic temperature dependency measurement.

First, the toner used in the image forming method and the image forming apparatus of the present invention will be described.
The toner used in the present invention has a tan δ peak in a range of 40 ° C. or higher and 70 ° C. or lower in dynamic viscoelastic temperature dependency measurement, and the peak value is less than 2.0. .
Note that tan δ (tan Delta: dynamic loss tangent of dynamic viscoelasticity) is obtained by measuring storage elastic modulus G ′ and loss elastic modulus G ″ by measuring dynamic viscoelastic temperature dependence, and G ″ / G ′. Is defined by Here, G ′ is an elastic response component of an elastic modulus in the relationship of stress generated with respect to strain at the time of deformation, and energy for deformation work is stored. The viscosity response component of the elastic modulus is G ″. Further, tan δ defined by G ″ / G ′ is a measure of the degree of energy loss and storage for deformation work.

  The storage elastic modulus G ′ and the loss elastic modulus G ″ can be measured using, for example, a rotating plate rheometer (manufactured by TA Instruments: ARES). In the present invention, a rheometer (Rheometric Scientific Co., Ltd .: ARES rheometer) was used, and a temperature rise measurement was performed under the condition of a frequency of 1 Hz using a parallel plate. After the sample set is cooled to room temperature at about 120 ° C. to 140 ° C., it is heated at a rate of temperature increase of 1 ° C./min. Tan δ was measured.

  In the toner used in the present invention, the tan δ peak exists between 40 ° C. and 70 ° C., and the peak value (hereinafter sometimes referred to as “specific peak value”) is less than 2.0. As a result, in the fixing process described later, the adhesiveness when the toner on the transfer material starts to melt from room temperature decreases, and the toner adheres to the wear-resistant additive of the fixing member and resists when the paper dust is taken in. It is possible to prevent the dirt from adhering to the abrasive additive. As a result, it is possible to suppress the offset phenomenon that causes the toner adhering to the fixing member to be transferred to the transfer target body and cause background staining of the transfer target body. The specific peak value is preferably less than 2.0, and more preferably less than 1.7. On the other hand, the specific peak value is preferably 1.0 or more from the viewpoint of preventing an increase in fixing temperature.

  On the other hand, if the specific peak value is 2.0 or more, the adhesiveness is strong, and further, the toner adheres strongly to the wear-resistant additive of the fixing member due to the pressure during fixing, and the initial period of printing There is no problem, but the releasability cannot be maintained for a long time. Further, the adhered toner is transferred to the transfer body, and an offset phenomenon that causes background contamination of the transfer body occurs.

The following two methods are mentioned as a method of controlling the specific peak value to be less than 2.0.
The first method is a method in which fine particles having a particle size of 0.1 μm or less are dispersed in the toner to suppress the viscous behavior during the glass transition of the binder resin.
The second method is to use a crystalline resin as a binder resin in combination with an amorphous resin, so that the crystalline resin is finely dispersed in the amorphous resin, and the viscous behavior during the glass transition of the binder resin. It is a method to suppress.
Of the above methods, the second method is preferable in that low temperature fixing is possible.

  Examples of the fine particles used in the first method include silica particles, alumina particles, magnesia particles, inorganic particles such as calcium carbonate, and resin particles such as divinylbenzene crosslinked particles. Among them, small particle diameters are easily obtained. Silica particles whose hydrophilicity / hydrophobicity can be easily controlled by surface treatment are preferable from the viewpoints of viscoelasticity due to affinity with the binder resin and charge adjustment of the toner.

  The fine particles have a particle size of 0.1 μm or less, preferably 0.05 μm or less, and more preferably 0.02 μm or less. Further, the content of fine particles in the toner is preferably 5% by mass or less and 30% by mass or less, and more preferably 7% by mass or less and 20% by mass or less. Here, the particle size of the fine particles is measured by observation with an electron microscope or the like and image analysis, a laser diffraction particle size analyzer, or a dynamic light scattering nanotrack particle size analyzer.

  In the second method, the crystalline resin needs to be compatible with the amorphous resin, and a preferable combination of the crystalline resin and the amorphous resin is a combination of the crystalline polyester resin and the amorphous polyester resin. Combinations include a combination of an amorphous polyamide resin and a crystalline polyamide resin, and a combination of a crystalline polyester resin and an amorphous polyester resin is preferred.

  The toner used in the present invention forms an image by a fixing device using a fixing member having a surface layer of a fixing member described later formed on a rubber elastic layer having a thickness of 0.15 mm to 4 mm. In the dynamic viscoelastic temperature dependency measurement, the tan δ value at a temperature at which G ″ is 100000 Pa is preferably 1.7 or more and less than 3.5 (more preferably 1.7 or more and less than 2.5). . When the tan δ value is 1.7 or more and less than 3.5 by using the fixing member, it is possible to suppress the toner component from remaining in the filler of the fixing surface member when the melted image is peeled off, and the toner The liquid in a molten state is sufficient, and color development preferable as a color image can be obtained.

  As a method for controlling the tan δ value at a temperature at which G ″ = 100,000 Pa to 1.7 or more and less than 3.5, a method for adjusting the resin molecular weight, a method for expressing thixotropy with the aforementioned internally added fine particles, a toner The method of adjusting the amount of ionic crosslinking using a chelating agent at the time of preparation is mentioned.

  Further, the toner used in the present invention is a fixing member in which the surface layer of the fixing member described later is a fixing member formed on a rubber elastic layer having a thickness of 0 mm or more and less than 0.15 mm. In the measurement of dynamic viscoelastic temperature dependence, it is preferable that the tan δ value at a temperature at which G ″ is 100000 Pa is 0.5 or more and less than 1.7 (more preferably 1.0 or more and less than 1.7). When the tan δ value is 1.0 or more and less than 1.7, the toner component can be prevented from remaining in the filler of the fixing surface member when the melted image is peeled off, and the flow of the toner in the molten state can be suppressed. It is sufficient and a preferable black image is obtained.

  As a method for controlling the tan δ value at a temperature at which G ″ = 100,000 Pa to 0.5 or more and less than 1.7, a method for adjusting the resin molecular weight, a method for expressing thixotropy by the aforementioned internally added fine particles, a toner The method of adjusting the amount of ionic crosslinking using a chelating agent at the time of preparation is mentioned.

  Hereinafter, the constituent components of the toner used in the present invention using a crystalline polyester resin and an amorphous polyester resin as a binder resin, which is a preferable combination, will be described together with a toner production method.

-Polyester resin-
The polyester resin such as a crystalline polyester resin or an amorphous polyester resin in the toner used in the present invention is preferably synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the polyester resin, or a synthesized product may be used.

  Here, the “crystalline polyester resin” refers to a resin having a clear endothermic peak rather than a stepwise endothermic amount change in differential scanning calorimetry (DSC). On the other hand, a resin in which a stepwise endothermic change is recognized in DSC means an “amorphous polyester resin”.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, fumaric acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. Aliphatic dicarboxylic acids such as 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malon Aromatic dicarboxylic acids such as dibasic acids such as acid and mesaconic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the like, and these anhydrides and lower alkyl esters thereof are also included. is not.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Furthermore, it is also possible to contain a dicarboxylic acid component having a double bond in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of the dicarboxylic acid include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  Examples of the polyhydric alcohol component include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, and glycerin; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A And the like; and aromatic diols such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; One or more of these polyhydric alcohols can be used.

  In the case of an amorphous polyester resin, among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable. On the other hand, in the case of a crystalline polyester resin, an aliphatic diol is preferable, and a linear aliphatic diol having 7 to 20 carbon atoms in the main chain portion is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that good toner blocking resistance, image storage stability, and low-temperature fixability may not be obtained. Further, when the number of carbon atoms is less than 7, when the polycondensation with aromatic dicarboxylic acid is performed, the melting point becomes high and fixing at low temperature may be difficult. On the other hand, when the number exceeds 20, it is difficult to obtain practical materials. easy. The carbon number is more preferably 14 or less.

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester resin include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1 , 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1, Examples include, but are not limited to, 13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

  Among the polyhydric alcohol components preferably used for the synthesis of the crystalline polyester, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90 mol% or more. When the content of the aliphatic diol component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that good toner blocking resistance, image storage stability and low-temperature fixability may not be obtained. is there.

  If necessary, monovalent acids such as acetic acid and benzoic acid, and monovalent alcohols such as cyclohexanol and benzyl alcohol can be used for the purpose of adjusting the acid value and the hydroxyl value.

  The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, a catalyst is added to the polyhydric alcohol and polyhydric carboxylic acid, if necessary, and blended in a reaction vessel equipped with a thermometer, a stirrer, and a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas). , Heated at 150-250 ° C to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  Examples of the catalyst used for the synthesis of this polyester resin include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. The amount of the catalyst added is preferably 0.01 to 1% by mass relative to the total amount of raw materials.

  The molecular weight of the amorphous polyester resin used in the toner of the present invention is a molecular weight measurement by the gel permeation chromatography (GPC) method of tetrahydrofuran (THF) soluble matter, and the weight average molecular weight (Mw) is 5,000 to 200,000. The number average molecular weight (Mn) is preferably in the range of 2000 to 10,000, and the molecular weight distribution Mw / Mn is in the range of 1.5 to 50. It is preferable that it is a range, and it is the range of 2-10 more suitably.

  The crystalline polyester resin preferably has a weight average molecular weight (Mw) of 5000 to 70000, more preferably 15000 to 50000, and a number average molecular weight (Mn) of 2000 to 20000. The molecular weight distribution Mw / Mn is preferably in the range of 1.5 to 10, and more preferably in the range of 2.0 to 4.0.

  When the weight average molecular weight and number average molecular weight are smaller than the above ranges, it is effective for low-temperature fixability, but it also adversely affects storage stability such as toner blocking because it lowers the glass transition point of the toner. There is. On the other hand, if the molecular weight is larger than the above range, the hot offset resistance can be sufficiently provided, but the low-temperature fixability is deteriorated and the oozing of the crystalline polyester phase present in the toner is inhibited, so that the document storage stability is reduced. May be adversely affected. Therefore, by satisfying the above conditions, it becomes easy to achieve both low-temperature fixability, hot offset resistance, and document storage stability.

  The acid value of the polyester resin (the number of mg of KOH required to neutralize 1 g of resin) is easy to obtain the above-mentioned preferred molecular weight distribution, and it is easy to ensure the granulation property of the toner particles by the emulsion dispersion method. The environmental stability (stability of chargeability when temperature and humidity change) of the obtained toner is easy to maintain, and therefore, it is preferably in the range of 1 to 30 mgKOH / g. The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio of the raw polyhydric carboxylic acid and polyhydric alcohol and the reaction rate. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

  The glass transition temperature of the amorphous polyester resin used in the present invention is preferably in the range of 35 to 100 ° C., and is 50 to 80 ° C. from the viewpoint of the balance between storage stability and toner fixing property. Is more preferred. When the glass transition temperature is less than 35 ° C., the toner tends to be blocked during the storage or in the developing machine (a phenomenon in which toner particles are aggregated into a lump). On the other hand, if the glass transition temperature exceeds 100 ° C., the fixing temperature of the toner becomes high, which is not preferable.

  The melting point of the crystalline polyester resin used in the present invention is preferably in the range of 60 to 120 ° C, and more preferably in the range of 70 to 100 ° C. When the melting point of the crystalline polyester resin is less than 60 ° C., the powder is likely to be aggregated or the storage stability of the fixed image may be deteriorated. On the other hand, if the temperature exceeds 120 ° C., image roughness may occur and low-temperature fixability may be impaired. In addition, melting | fusing point of the said crystalline polyester resin was calculated | required as the peak temperature of the endothermic peak obtained by the said differential scanning calorimetry (DSC).

-Colorant-
The colorant in the toner used in the present invention is not particularly limited as long as it is a known colorant. For example, carbon black such as furnace black, channel black, acetylene black, thermal black, bengara, bitumen, titanium oxide, etc. Inorganic pigments, fast yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine, para-brown and other azo pigments; copper phthalocyanine, metal-free phthalocyanine and other phthalocyanine pigments; flavantron yellow, dibromoanthrone orange, perylene red, quinacridone red, And condensed polycyclic pigments such as dioxazine violet.

  Specifically, Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrarozone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment 57: 1, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Examples thereof include various pigments such as CI Pigment Blue 15: 3, and these can be used alone or in combination of two or more.

  The content of the colorant in the toner is preferably in the range of 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin. If necessary, a surface-treated colorant may be used, or pigment dispersion may be used. It is also effective to use an agent. By selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner, and the like can be obtained.

-Release agent-
The release agent in the toner used in the present invention is not particularly limited as long as it is a known release agent. For example, natural waxes such as carnauba wax, rice wax, and candelilla wax; low molecular weight polypropylene, low molecular weight polyethylene , Sazol wax, microcrystalline wax, Fischer-Tropsch wax, paraffin wax, montan wax and the like, or mineral / petroleum waxes; ester waxes such as fatty acid esters and montanic acid esters; It is not something. Moreover, these mold release agents may be used individually by 1 type, and may be used together 2 or more types.

  The melting point of the release agent is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of storage stability. Moreover, it is preferable that it is 110 degrees C or less from a viewpoint of offset resistance, and it is more preferable that it is 100 degrees C or less.

  The content of the release agent is preferably in the range of 2 to 30 parts by mass, and more preferably in the range of 3 to 20 parts by mass with respect to 100 parts by mass of the binder resin. If the content of the release agent is less than 2 parts by mass, the effect of adding the release agent is not obtained, and hot offset at a high temperature may be caused. On the other hand, if the amount exceeds 30 parts by mass, the chargeability may be adversely affected, and the mechanical strength of the toner tends to be reduced. There is.

  In addition to the above components, various components such as an internal additive, a charge control agent, inorganic powder (inorganic particles), and organic particles can be further added to the toner of the present invention as necessary.

Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.
When the magnetic material is used as a magnetic toner, the ferromagnetic particles preferably have an average particle size of 2 μm or less, more preferably about 0.1 to 0.5 μm. The amount to be contained in the toner is preferably 20 to 200 parts by mass with respect to 100 parts by mass of the resin component, and particularly preferably 40 to 150 parts by mass with respect to 100 parts by mass of the resin component. Further, it is preferable that the magnetic characteristics when applied with 10K oersted are those having a coercive force (Hc) of 20 to 300 oersted, saturation magnetization (σs) of 50 to 200 emu / g, and residual magnetization (σr) of 2 to 20 emu / g.

  Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  The inorganic powder is added mainly for the purpose of adjusting the viscoelasticity of the toner. For example, normal toners such as silica, alumina, titania, calcium carbonate, magnesium carbonate, calcium phosphate, and cerium oxide are listed in detail below. All inorganic particles used as surface external additives can be mentioned.

Examples of inorganic particles and organic particles externally added to the toner surface include the following.
Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, Examples include Bengala, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, and silicon nitride. Among these, silica particles and titanium oxide particles are preferable, and hydrophobically treated particles are particularly preferable.

Inorganic particles are generally used for the purpose of improving fluidity. The primary particle diameter of the inorganic particles is preferably in the range of 1 to 200 nm, and the addition amount is preferably in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of the toner.
Organic particles are generally used for the purpose of improving cleaning properties and transfer properties. Specifically, for example, fluorine resin powders such as polyvinylidene fluoride and polytetrafluoroethylene, fatty acid metal salts such as zinc stearate and calcium stearate. , Polystyrene, polymethyl methacrylate and the like.

  The production of the electrostatic latent image developing toner of the present invention is preferably carried out by wet granulation. Examples of the wet granulation method include known melt suspension methods, emulsion aggregation methods, dissolution suspension methods, and the like. In the present invention, among them, a wax structure having a low melting point can be obtained by using a capsule structure. An emulsification aggregation method that prevents exposure of the toner to the toner surface and achieves good powder fluidity is preferably used.

The emulsion aggregation method includes an emulsification step in which each raw material such as a polyester resin and a colorant is dispersed in an aqueous dispersion medium, an aggregation step in which aggregated particles are produced from a raw material dispersion obtained by mixing each dispersion, and the aggregated particles. At least a fusing step of fusing to obtain toner. In addition, a coating step (shell layer forming step) for covering the surface of the aggregated particles with the same or different resin particles as the binder resin is included as necessary.
Hereinafter, each step will be described in detail.

-Emulsification process-
In the emulsion aggregation method, since the binder resin and the colorant are mixed as respective emulsified particles as a raw material dispersion, the emulsification step is a step of preparing an emulsified dispersion of the above raw material. Therefore, first, the binder resin needs to be dispersed in advance as resin particles in the raw material dispersion.

  The volume average particle diameter of the emulsified resin particles is preferably 0.01 to 1 μm, more preferably 0.03 to 0.8 μm, and further preferably 0.03 to 0.6 μm. When the average particle diameter exceeds 1 μm, the particle diameter distribution of the finally obtained toner for developing an electrostatic latent image is broadened or free particles are generated, which tends to deteriorate performance and reliability. On the other hand, when the average particle size is within the above range, there are no disadvantages, the compositional uneven distribution among the toners is reduced, the dispersion in the toner is improved, and the variation in performance and reliability is advantageous. . The volume average particle diameter can be measured using, for example, a Coulter counter method, a photon correlation method, a laser diffraction / scattering method, a white light polarization method, or the like.

  The dispersion medium in the dispersion is preferably an aqueous medium. Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. In the present invention, it is preferable to add and mix a surfactant in the aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like. Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

When a polyester resin is used as the binder resin particles as in the present invention, the polyester resin is preferably a polyester resin having a self-water dispersibility containing a functional group that can be made anionic by neutralization. By neutralizing a part or all of the functional groups that can be anionic with a base, a stable aqueous dispersion can be formed under the action of an aqueous medium.
In addition, examples of the functional group that can be converted into an anionic type by neutralization in the polyester resin include acidic groups such as a carboxyl group and a sulfone group. Examples of the neutralizing agent include sodium hydroxide, potassium hydroxide, lithium hydroxide, Examples thereof include inorganic bases such as calcium hydroxide, sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

  Further, when a polyester resin that does not disperse in water, that is, does not have self-water dispersibility, is used as the binder resin, an ionic surfactant, a polymer is added to the resin solution and / or an aqueous medium mixed therewith. It is preferable to perform treatment using a homogenizer or a pressure discharge type disperser capable of applying a strong shearing force by adding and dispersing a polymer electrolyte such as an acid or a polymer base, heating it to a melting point or higher. By treating in this way, it can be easily dispersed in particles of 0.5 μm or less. When the ionic surfactant or polymer electrolyte is used, the concentration in the aqueous medium is suitably 0.5 to 5% by mass. The mold release agent described later also applies to this.

  Furthermore, as a method of dispersing another polyester resin, a phase inversion emulsification method may be mentioned. In the phase inversion emulsification method, a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to the organic continuous phase (O phase), and the aqueous medium (W Phase), the resin is converted from W / O to O / W (so-called phase inversion) to form a discontinuous phase, and the resin is dispersed and stabilized in the form of particles in an aqueous medium. It is.

  Examples of the organic solvent used for this phase inversion emulsification include ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, and tert. -Alcohols such as amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, tetrahydrofuran , Ethers such as dimethyl ether, diethyl ether, dioxane, methyl acetate, ethyl acetate, acetic acid-n-propyl, isopropyl acetate, acetic acid-n-butyl, isobutyl acetate, vinegar -Sec-butyl, acetate-3-methoxybutyl, methyl propionate, ethyl propionate, butyl propionate, dimethyl oxalate, diethyl oxalate, dimethyl succinate, diethyl succinate, diethyl carbonate, dimethyl carbonate, Ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether , Diethylene glycol ethyl ether acetate Glycol derivatives such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, dipropylene glycol monobutyl ether, 3-methoxy-3-methylbutanol, 3-methoxy Examples include butanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate and the like. These solvents can be used singly or in combination of two or more.

  In the above phase inversion emulsification, when the binder resin is dispersed in water, it is preferable to neutralize part or all of the carboxyl groups in the resin with a neutralizing agent, if necessary. Examples of the neutralizing agent include inorganic alkalis such as potassium hydroxide and sodium hydroxide, ammonia, monomethylamine, dimethylamine, triethylamine, monoethylamine, diethylamine, triethylamine, mono-n-propylamine, dimethyl-n-propylamine, Amines such as monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-aminoethylethanolamine, N-methyldiethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N, N-dimethylpropanolamine 1 type or 2 types or more selected from these can be used. By adding these neutralizing agents, the pH during emulsification can be adjusted to neutral, and hydrolysis of the resulting polyester resin dispersion can be prevented.

  Further, a dispersant may be added also during the phase inversion emulsification for the purpose of stabilizing the dispersed particles and preventing the thickening of the aqueous medium. Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and oleic acid. Anionic surfactants such as sodium, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, Polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl amine, etc. Surfactants such as on-surfactant, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate. These dispersants may be used alone or in combination of two or more. The dispersant is preferably added in an amount of 0.01 to 20 parts by mass with respect to 100 parts by mass of the binder resin.

  The emulsification temperature during phase inversion emulsification is preferably not higher than the boiling point of the organic solvent and not lower than the melting point (or transition point) of the release agent. If the emulsification temperature is not higher than the melting point or transition point of the release agent, a particle dispersion containing the release agent cannot be obtained. In addition, when emulsifying above the boiling point of the organic solvent, the emulsification may be performed with a pressure-sealed device.

As the colorant to be emulsified and dispersed as the raw material dispersion, the colorants described above can be used.
As a method for dispersing the colorant, for example, a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and the colorant is not limited at all. If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant. Hereinafter, such a colorant dispersion may be referred to as a “colored particle dispersion”. As the surfactant or dispersant used for dispersion, those according to the dispersant that can be used when dispersing the binder resin can be used.

  The addition amount of the colorant is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and still more preferably 2 to 10% by mass with respect to the total amount of the polymer. 2 to 7% by mass is particularly preferable, but it is more preferable that the image surface after fixing is not roughened. When the content of the colorant is increased, the thickness of the image can be reduced when an image having the same density is obtained, which is advantageous in terms of prevention of offset.

  These colorants may be added to the mixed solvent at the same time as other particle components, or may be divided and added in multiple stages.

As the release agent emulsified and dispersed as the raw material dispersion, the release agent described above can be used.
The release agent is a homogenizer that can disperse together with an ionic surfactant, etc. in water according to the case of emulsifying and dispersing a polyester resin that does not have self-water dispersibility, heat it above its melting point, and apply a strong shearing force. Or a pressure discharge type disperser to adjust the dispersed particle diameter to 1 μm or less. As the dispersion medium in the release agent dispersion liquid, a dispersion medium according to the binder resin dispersion medium can be used.

  As an apparatus for mixing and dispersing the binder resin and the colorant with an aqueous medium, for example, a homomixer (Special Machine Industries Co., Ltd.), Thrasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.), Examples thereof include continuous emulsion dispersers such as a microfluidizer (Mizuho Industrial Co., Ltd.), a Menton Gorin homogenizer (Gorin Inc.), a nanomizer (Nanomizer Inc.), a static mixer (Noritake Company), and the like.

  The content of the resin particles contained in the binder resin dispersion (resin particle dispersion) in the emulsification step, the content of the colorant in the colorant dispersion (colored particle dispersion), and the release agent dispersion 5-50 mass% is suitable for content of the mold release agent in (release agent particle dispersion liquid), More preferably, it is 10-40 mass%. When the content is outside the above range, the particle size distribution may be widened and the characteristics may be deteriorated.

In the present invention, other components such as the internal additive, the charge control agent, and the inorganic powder described above may be dispersed in the binder resin dispersion according to the purpose.
In addition, as the charge control agent in the present invention, a material that is difficult to dissolve in water is preferable in terms of controlling ionic strength that affects the stability of the aggregation process and the fusion process and reducing wastewater contamination.

  The average particle size of the other components is preferably 1 μm or less, and more preferably 0.01 to 0.5 μm. When the average diameter exceeds 1 μm, the particle diameter distribution of the finally obtained toner for developing an electrostatic latent image is broadened, or free particles are generated, which tends to deteriorate performance and reliability. On the other hand, when the average particle diameter is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toner is good, and the variation in performance and reliability is advantageous.

-Aggregation process-
In the agglomeration step, the respective dispersions of resin particles, colorants and the like obtained in the emulsification step are mixed (this mixture is referred to as “raw material dispersion”), and heated to a temperature of 50 ° C. or less, for example. Aggregated particles are formed by aggregating the dispersed particles.

  In addition, before performing an aggregation process, it is also possible to add the said high acid value dispersing agent as an additive to the resin particle dispersion (polyester resin dispersion) obtained by the emulsification process. By adding a high acid value dispersing agent and adsorbing it on the emulsified particle surface of the polyester resin, the surface of the emulsified particle is maintained in a state where the electrostatic repulsion is sufficiently applied, thereby suppressing rapid particle growth in the aggregation process. It becomes possible to do. In addition, since the electrostatic repulsion effect derived from these anionic dissociation groups acts also in the fusion step described later, adhesion between the aggregated particles can be sufficiently prevented, and stable granulation control can be performed. Furthermore, the method of adding the high acid value dispersant after completion of the aggregation can sufficiently prevent the aggregation particles from adhering in the fusing step, and enables stable granulation control.

  Agglomerated particles are formed by acidifying the pH of the raw material dispersion, adding a flocculant at room temperature (20-25 ° C, the same applies to this) under high-speed stirring with a rotary shearing homogenizer, and increasing by initial aggregation. This is done by dispersing the flocculant in the viscous raw material dispersion. As the said pH, the range of 2-6 is preferable, and the range of 3-6 is more suitable.

  As described above, an acidic pH range is suitable for the formation of aggregated particles. For example, since the resin particle dispersion of a polyester resin obtained by the phase inversion emulsification method has a pH in the range of 7 to 8, If a colorant dispersion or a release agent dispersion having a pH of 3 to 5 is mixed or adjusted to the above pH for aggregation, the balance of polarity is lost and slow aggregation occurs. Therefore, when the pH of the resin particle dispersion of the polyester resin is on the alkali side, a surfactant or the above-mentioned high acid value dispersant is added in advance at room temperature to allow the surfactant and dispersant to blend into the resin particle surface. After that, it is preferable to adjust the pH by mixing a colorant and a release agent.

  As the aggregating agent used in the aggregating step, it is preferable to use a divalent or higher-valent metal complex in addition to a surfactant having an opposite polarity to the surfactant used when preparing the dispersion, an inorganic metal salt, and the like. it can. In particular, the use of a metal complex is preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

  In the aggregation step, in order to suppress rapid aggregation due to heating, the pH may be adjusted while stirring and mixing at room temperature, and a dispersion stabilizer may be added as necessary.

  In the final toner, it is preferable to add a coating step after the aggregation step for the purpose of further improving the chargeability and powder flowability. In this coating step, the same or different resin particles as the binder resin are adhered to the surface of the above-mentioned aggregated particles to form adhered particles to form a coating layer (that is, a toner having a core-shell structure). . The formation can be performed by additionally adding a dispersion liquid containing a binder resin or other resin particles to the dispersion liquid in which the aggregated particles are formed in the aggregation process. It may be added. In addition, as a binder resin (resin particle) used for formation of a coating layer, the thing according to the above-mentioned binder resin (namely, binder resin for core layers) can be used. Also in the coating process, the pH and surfactant are selected according to the agglomeration process according to the resin used, and the coated aggregated particles are obtained with care so as not to adhere to the surface of the aggregated particles. This coating step is also effective in guiding raw material particles that have not been taken into the aggregated particles in the aggregation step.

-Fusion process-
In the fusion step, the agglomeration is stopped by advancing the aggregation by adjusting the pH of the suspension of the agglomerated particles (or attached particles) to a range of 6.0 to 7.5 under stirring according to the agglomeration step. The aggregated particles (or adhered particles) are fused by heating at a temperature equal to or higher than the melting point of the binder resin. Although depending on the liquidity of the dispersion containing the aggregated particles (raw material dispersion), if the pH at which aggregation is stopped is not appropriate, the aggregated particles will be dispersed during the temperature rising process for fusing, resulting in a high yield. There is a possibility that the agglomeration is worsened or the aggregation cannot be stopped, and the particle size growth further proceeds, resulting in a large particle size.

  When the crystalline polyester resin is contained in the aggregated particles, the heating temperature at the time of fusing is not a problem as long as the temperature is not lower than the melting point, and if not included, the temperature is not lower than the glass transition point of the amorphous resin. The heating time may be performed as long as desired fusion is performed, and may be performed for about 0.5 to 3 hours. When heated for a longer time, the release agent contained in the aggregated particles is likely to be exposed on the toner surface. Therefore, although it is effective for fixing properties, it is not preferable to heat for a long time because it adversely affects the storage stability of the toner.

  In the fusion step, a crosslinking reaction may be performed when the binder resin is heated to a melting point or a glass transition point or higher, or after the fusion is completed. In addition, a crosslinking reaction can be performed simultaneously with the fusion. When the crosslinking reaction is performed, for example, an unsaturated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin is used, and a radical reaction is caused in the resin to introduce a crosslinked structure. At this time, the following polymerization initiator is preferably used.

Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) -3,3,5-trimethyl Cyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbo) Nyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydroterephthalate , Di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butyl Peroxytrimethyladipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2′-azobis (2-methylpropionamidine dihydrochloride), 2,2′-azobis [N -(2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.
These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the binder resin and the type and amount of the coexisting colorant.

  The polymerization initiator may be previously mixed with the binder resin before the emulsification step, or may be incorporated into the aggregated particles in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step. When the polymerization initiator is introduced during the aggregation process, the coating process, the fusion process, or after the fusion process, a solution in which the polymerization initiator is dissolved or emulsified is added to the resin particle dispersion or the like. These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

The fused particles obtained by fusing can be made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to perform sufficient cleaning in the cleaning step.
In the drying step, methods such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, and a flash jet method can be employed.

The dried toner particles preferably have a water content of 1.5% by mass or less, more preferably 1.0% by mass or less, at 28 ° C./85% RH for 3 days. When the water content is in the above range, the charge amount of the toner does not decrease under high humidity conditions, and the toner charging characteristics due to humidity change can be stabilized.
The toner moisture content was measured by leaving 2 g of toner in an environment of 28 ° C. and humidity 85% RH for 3 days, and then using a moisture analyzer (manufactured by METTLER TOLEDO) at a heating temperature of 150 ° C. This can be done by measuring the amount of evaporation.

  To the toner particles granulated through the drying step as described above, various known external additives such as the inorganic particles and organic particles described above can be added as other components depending on the purpose.

  The volume average particle diameter of the toner for developing an electrostatic latent image of the present invention is preferably in the range of 1 to 20 μm, and more preferably in the range of 2 to 8 μm. Further, the number average particle diameter is preferably in the range of 1 to 20 μm, and more preferably in the range of 2 to 8 μm.

  The volume average particle size and the number average particle size can be measured by using a Multisizer II type (manufactured by Beckman-Coulter) with an aperture diameter of 50 μm. At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

  In the toner of the present invention, the softening temperature T f1 / 2 in the measurement of the flow tester viscosity is preferably 115 ° C. or less, and more preferably 110 ° C. or less. When the temperature is higher than 115 ° C., the melt viscosity at the time of fixing is high, which may adversely affect the low-temperature fixability, which is not preferable.

  The toner used in the present invention is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.

  There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include acid copolymers, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, etc., but are not limited thereto. Absent.

  Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, a magnetic material is used. Preferably there is.

  The volume average particle size of the core material of the carrier is generally 10 to 500 μm, and preferably 30 to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  In the present invention, the shape factor SF1 of the carrier is preferably in the range of 115 to 140. This is because a sufficient charge amount can be obtained at the time of restarting printing by appropriately controlling the contact area between the carrier and the toner as described above. In particular, the toner containing the crystalline polyester resin is hardly stressed, and the durability of the developer can be improved. The shape factor SF1 is more preferably in the range of 125 to 135.

Here, the shape factor SF1 is obtained by the following equation (3).
SF1 = (ML ² / A) × (π / 4) × 100 (3)
In the above formula (3), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, an optical microscope image of higher alcohol particles dispersed on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 100 particles are obtained, calculated by the above equation (3), and the average Obtained by determining the value.

  The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

  On the other hand, when the toner for developing an electrostatic latent image of the present invention is used as a one-component developer and a magnetic toner in which a magnetic substance is contained in the toner is used, a magnet incorporated in the developing sleeve is used to There is a method for conveying and charging the toner. When non-magnetic toner containing no magnetic material is used, there is a method in which a blade and a fur brush are used to forcibly frictionally charge with a developing sleeve, and the toner is adhered to the sleeve and conveyed.

Next, the fixing unit will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an example of a heat fixing device (fixing means) in the present invention. A fixing device 60 shown in FIG. 1 includes a fixing roll 61 as an example of a fixing member, an endless belt 62, and a pressure pad 64 as an example of a pressure member pressed from the fixing roll 61 via the endless belt 62. It is configured.

The fixing roll 61 is configured by laminating a rubber elastic layer 612 and a surface layer 613 around a metal core (cylindrical cored bar) 611.
Inside the fixing roll 61, a halogen lamp 66 is disposed as a heat source. On the other hand, a temperature sensor 69 is disposed in contact with the surface of the fixing roll 61. The lighting of the halogen lamp 66 is controlled based on the temperature measurement value by the temperature sensor 69, and the surface temperature of the fixing roll 61 is adjusted to maintain a predetermined set temperature (for example, 170 ° C.).
The endless belt 62 is rotatably supported by a pressure pad 64 and a belt traveling guide 63. The contact portion N is disposed in pressure contact with the fixing roll 61.

  The pressure pad 64 is disposed inside the endless belt 62 so as to be pressed against the fixing roll 61 via the endless belt 62, and forms a contact portion N with the fixing roll 61. In the pressure pad 64, a pre-contact member 64a for securing a wide contact portion N is disposed on the inlet side of the contact portion N, and a peeling contact member 64b for distorting the fixing roll 61 is provided at the outlet of the contact portion N. Arranged on the side. Further, in order to reduce the sliding resistance between the inner peripheral surface of the endless belt 62 and the pressure pad 64, a low friction sheet 68 is provided on the surface of the pre-contact member 64a and the peeling contact member 64b that contacts the endless belt 62. . The pressure pad 64 and the low friction sheet 68 are held by a metal holder 65.

  Furthermore, a belt traveling guide 63 is attached to the holder 65 so that the endless belt 62 can smoothly rotate. That is, the belt running guide 63 is made of a material having a small static friction coefficient in order to rub against the inner peripheral surface of the endless belt 62. Further, the belt running guide 63 is formed of a material having low thermal conductivity so that it is difficult to remove heat from the endless belt 62.

  The fixing roll 61 is rotated in the direction of arrow C by a drive motor (not shown), and the endless belt 62 is also rotated by this rotation. The sheet (transfer object) P on which the transferred image is electrostatically transferred is guided by the fixing inlet guide 56 and conveyed to the contact portion N. When the paper P passes through the contact portion N, the toner image on the paper P is fixed by the pressure acting on the contact portion N and the heat supplied from the fixing roll 61. In the fixing device 60, since the contact portion N can be widely configured by the concave pre-contact member 64a that substantially follows the outer peripheral surface of the fixing roll 61, stable fixing performance can be ensured.

In addition, in the fixing device 60, by disposing the peeling contact member 64b so as to protrude from the outer peripheral surface of the fixing roll 61, distortion of the fixing roll 61 is locally caused in the exit region (peeling contact portion) of the contact portion N. It can also be configured to be large. If the peeling contact member 64b is arranged in this way, the fixed paper P passes through the locally formed distortion when passing through the peeling contact portion, and therefore winds around the fixing roll 61. The sheet P can be effectively peeled off.
In particular, by locally increasing the distortion of the fixing roll 61, it is possible to obtain high peeling performance with a small amount of distortion. Therefore, even when a thin heat-resistant resin is used as the surface layer 613 of the fixing roll 61, the occurrence of paper wrinkles on the paper P can be suppressed. Also, peeling between the rubber elastic layer 612 and the surface layer 613 is unlikely to occur, and the reliability of the component performance over a long period can be improved in addition to maintaining the peeling performance.

Furthermore, since the distortion amount of the fixing roll 61 can be reduced, the rubber elastic layer 612 of the fixing roll 61 can be thinned. Therefore, since the heat capacity of the fixing roll 61 can be reduced, the warm-up time can be shortened and the power consumption can be reduced. Further, since the rubber elastic layer 612 having a low thermal conductivity can be thinned, the thermal resistance between the inner surface and the outer surface of the fixing roll 61 can be reduced and the thermal response can be improved, so that the speed of the image forming apparatus can be increased. Is also suitable.
Note that a peeling member 70 may be disposed on the downstream side of the contact portion N of the fixing roll 61 as an auxiliary means for peeling. The peeling member 70 is held by a holder 72 in a state in which the peeling baffle 71 is close to the fixing roll 61 in a direction (counter direction) opposite to the rotation direction of the fixing roll 61.

Next, each member constituting the fixing device 60 will be described in detail. First, in the fixing roll 61, the core 611 is formed of a cylindrical body made of a metal having high thermal conductivity such as iron, aluminum, and SUS. The outer diameter and thickness of the core 611 can be reduced in diameter and thickness in the fixing device 60 of the present embodiment because the pressing force of the pressure pad 64 is small.
As the rubber elastic layer 612, any material can be used as long as it is an elastic body having high heat resistance. In particular, it is preferable to use an elastic body such as rubber or elastomer having a rubber hardness of about 25 to 40 ° (JIS-A), and specific examples include silicone rubber and fluorine rubber.

  In the present invention, the thickness of the rubber elastic layer 612 is preferably in the range of 0.15 mm or more and less than 4 mm in the case of color image formation, and more preferably in the range of 0.2 mm or more and less than 3 mm. When the rubber elastic layer has a thickness of less than 0.15 mm, the peelability of the fixed image is poor, image blurring or offset is generated, and the filler on the surface of the fixing member tends to accumulate dirt and has a releasability. It may get worse. If it exceeds 4 mm, sufficient heat energy may not be supplied, for example, when fixing with continuous paper passing. If this is to be avoided, the fixing temperature will be set higher, and the warm-up time will be longer. It may become long.

  On the other hand, in the present invention, the thickness of the rubber elastic layer 612 is preferably in the range of 0 mm or more and less than 0.15 mm from the viewpoint of print productivity due to heat conduction in the case of black and white image formation.

  As the surface layer 613, any resin can be used as long as it is a heat-resistant resin. For example, a silicone resin, a fluororesin, or the like can be used. From the viewpoint, a fluororesin is suitable. As the fluororesin, PFA, PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene hexafluoropropylene copolymer), or the like can be used. The thickness of the surface layer 613 is preferably 5 to 30 μm, more preferably 10 to 20 μm. If the thickness of the surface layer 613 is less than 5 μm, the paper P tends to be wrinkled based on the distortion of the fixing roll 61, while if it exceeds 30 μm, the surface layer 613 becomes hard and defects such as uneven glossiness occur in the image. This is because the possibility increases and both are not preferable.

  In the present invention, a wear-resistant additive having a volume average particle size of 1 μm or less is dispersed in the surface layer 613. Therefore, since the size of the toner-derived fixed matter is reduced, it is easy to be polished and cleaned with paper or the like. Further, in the dynamic viscoelastic temperature dependency measurement, by using a toner having a tan δ peak in the range of 40 ° C. or more and 70 ° C. or less and having a peak value of less than 2.0, the adhesion of the toner is further increased. Longer life of the fixing member without occurrence of offset, because it can reduce wear, improve releasability maintenance, suppress wear, and also prevent toner from sticking to the wear-resistant additive Can be realized.

  Examples of the abrasion resistance additive include carbon black, silicon carbide, silicon nitride, alumina, magnesia, and the like, and carbon black and silicon carbide are preferable.

  The wear-resistant additive has a volume average particle size of 1 μm or less. When the volume average particle size of the wear-resistant additive exceeds 1 μm, the area where the toner component is fixed is large and the toner component tends to be deposited, resulting in poor releasability maintenance. Here, the volume average particle size of the wear-resistant additive is calculated using a laser diffraction scattering type particle size distribution measuring device (trade name: Microtrack MT3300, manufactured by Nikkiso Co., Ltd.). Is required.

  The content of the wear-resistant additive in the surface layer 613 is preferably 3% by mass or more and 20% by mass or less. When the content of the wear resistance additive is 3% by mass or more, a decrease in wear resistance can be sufficiently suppressed, and a decrease in thermal conductivity can also be suppressed. In addition, when the content of the wear-resistant additive is 20% by mass or less, the ratio of the wear-resistant additive deposited on the surface of the fixing roll increases, and the initial releasability does not deteriorate. The content of the wear-resistant additive is more preferably 3% by mass or more and 9% by mass or less, and further preferably 4% by mass or more and 7% by mass or less.

  In the present invention, the surface layer 613 is preferably formed by wet coating (also referred to as flow coating). Conventionally, powder coating (dry coating) has been the mainstream, but with this method it is difficult to uniformly disperse the above-mentioned anti-wear additive in the surface layer, so the surface becomes rough when the fixing roll is worn. It becomes easy and toner components may be deposited. According to wet coating, it is easy to uniformly disperse the wear-resistant additive in the surface layer. Therefore, even when the fixing roll is worn, the surface is hardly roughened and the toner component is difficult to deposit. As a result, it is possible to improve the releasability and maintenance of the fixing roll, wear resistance, and thermal conductivity.

  On the other hand, the endless belt 62 is an endless belt whose original shape is formed in a cylindrical shape, and includes a base layer and a surface layer coated on the surface or both surfaces of the base layer on the fixing roll 61 side. The base layer is formed of a polymer such as polyimide, polyamide, or polyimideamide, or a metal such as SUS, nickel, or copper, and has a thickness of 30 to 200 μm, preferably 50 to 125 μm, and more preferably about 75 to 100 μm. The surface layer coated on the surface of the base layer is made of a fluororesin such as PFA, PTFE, FEP, and has a thickness of about 5 to 100 μm, preferably about 10 to 30 μm.

As described above, the pressure pad 64 includes the pre-contact member 64 a and the peeling contact member 64 b and is supported by the holder 65. For the pre-contact member 64a, an elastic body such as silicone rubber or fluoro rubber, a leaf spring, or the like can be used. The surface on the fixing roll 61 side is formed in a concave shape that substantially follows the outer peripheral surface of the fixing roll 61. .
The peeling contact member 64b is formed of a heat-resistant resin such as PPS (polyphenylene sulfide), polyimide, polyester, polyamide, or a metal such as iron, aluminum, or SUS. As the shape of the peeling contact member 64b, the outer surface shape in the contact portion N is formed in a convex curved surface shape having a constant radius of curvature.

  The low friction sheet 68 is provided to reduce the sliding resistance (friction resistance) between the inner peripheral surface of the endless belt 62 and the pressure pad 64, and a material having a small friction coefficient and excellent wear resistance and heat resistance is suitable. ing. Specifically, sintered molded PTFE resin sheets, glass fiber sheets impregnated with Teflon (trade name), and the like can be used. The low friction sheet 68 may be configured separately from the pre-contact member 64a and the peeling contact member 64b, or may be configured integrally with the pre-contact member 64a and the peeling contact member 64b.

Further, as described above, the belt running guide 63 is made of a material having a low coefficient of friction and a low thermal conductivity so that heat is not easily taken from the endless belt 62 because it slides on the inner peripheral surface of the endless belt 62. A heat resistant resin such as PFA or PPS is used.
A lubricant application member 67 is disposed in the belt traveling guide 63 along the longitudinal direction of the fixing device 60. The lubricant application member 67 is disposed so as to be in contact with the inner peripheral surface of the endless belt 62 and supplies an appropriate amount of lubricant such as amine-modified silicone oil. As a result, the lubricant is supplied to the sliding portion between the endless belt 62 and the low friction sheet 68, and the sliding resistance between the endless belt 62 and the pressure pad 64 via the low friction sheet 68 is further reduced. 62 is smoothly rotated.

  Here, in the fixing device 60 of the present embodiment, irregular fine irregularities are formed on the inner peripheral surface of the endless belt 62. As described above, by forming irregular fine irregularities on the inner peripheral surface of the endless belt 62, it is possible to improve the ability of retaining the lubricant on the inner peripheral surface of the endless belt 62. As a result, the lubricant can be stably maintained at the sliding portion between the endless belt 62 and the low friction sheet 68, and therefore the sliding resistance between the endless belt 62 and the pressure pad 64 can be maintained over a long period of time. It can be kept low.

  The example in which the present invention is applied to the fixing device of the heat belt fixing system has been described above, but the application target of the present invention is not limited to this. For example, the present invention is also suitable for a fixing device such as a heat roll fixing method in which a toner image is heated through a heat-resistant thin layer belt to fix the toner on a transfer target.

In the present invention, as described above, when a toner having a tan δ value of 1.7 or more and less than 3.5 at a temperature at which G ″ = 100,000 Pa is used, the surface layer of the fixing member is thick. It is preferably formed on a rubber elastic layer having a thickness of 0.15 mm or more and less than 4 mm, and more preferably, the sheet discharge angle is separated from the fixing member by deformation of the rubber elastic layer. This form is preferably used for a color image forming apparatus.
On the other hand, in the present invention, when a toner having a tan δ value of 0.5 or more and less than 1.7 at a temperature at which G ″ = 100,000 Pa is used, the surface layer of the fixing member has a thickness from the viewpoint of heat conduction. A fixing member formed on a rubber elastic layer having a size of 0 mm or more and less than 0.15 mm is preferable. This form is preferably used for a monochrome image forming apparatus.

Hereinafter, the image forming method and the image forming apparatus of the present invention having the fixing unit will be specifically described with reference to the drawings.
FIG. 2 is a schematic diagram schematically showing a basic configuration of a preferred embodiment of the image forming apparatus.
The image forming apparatus 10 shown in FIG. 2 includes a latent image holding body 12, a charging unit 14, an electrostatic latent image forming unit 16, a developing unit 18, a transfer unit 20, a cleaning unit 22, a neutralizing unit 24, a fixing unit 26, and a cartridge 28. Is provided.
The developer accommodated in the developing means 18 and the cartridge 28 is a developer containing the toner used in the present invention described above.

  For convenience, FIG. 2 shows only a configuration having one developing means 18 and one cartridge 28 each containing a developer. However, for example, in the case of a color image forming apparatus, a number corresponding to the image forming apparatus. It is also possible to adopt a configuration including the developing means 18 and the cartridge 28.

  The image forming apparatus shown in FIG. 2 is an image forming apparatus having a configuration in which the cartridge 28 can be attached and detached, and the cartridge 28 is connected to the developing means 18 through the developer supply pipe 30. Therefore, when performing image formation, the developer stored in the cartridge 28 is supplied to the developing means 18 through the developer supply rod 30 to form an image using the developer over a long period of time. be able to. Further, when the amount of developer stored in the cartridge 28 is reduced, the cartridge 28 can be replaced.

  Around the latent image holding body 12, charging means 14 for uniformly charging the surface of the latent image holding body 12 in order along the rotation direction (arrow A direction) of the latent image holding body 12, and the latent image according to the image information. An electrostatic latent image forming means 16 for forming an electrostatic latent image on the surface of the holding body 12, a developing means 18 for supplying a developer to the formed electrostatic latent image, and a latent image holding body in contact with the surface of the latent image holding body 12 The drum-shaped transfer means 20 that can be driven to rotate in the direction of the arrow B in accordance with the rotation of the arrow 12 in the direction of the arrow A, the cleaning device 22 that contacts the surface of the latent image holding body 12, and the charge removal that neutralizes the surface of the latent image holding body 12 A means 24 is arranged.

  Between the latent image holding body 12 and the transfer means 20, a transfer target body 50 transported in the arrow C direction by a transport means (not shown) from the opposite side to the arrow C direction can be inserted. A fixing unit 26 having a built-in heating source (not shown) is disposed on the latent image holding body 12 in the direction of arrow C. The fixing unit 26 is provided with a pressure contact portion 32. Further, the transferred object 50 that has passed between the latent image holding body 12 and the transfer means 20 can be inserted through the pressure contact portion 32 in the direction of arrow C.

As the latent image holding member 12, for example, a photosensitive member or a dielectric recording member can be used.
As the photoreceptor, for example, a photoreceptor having a single layer structure or a photoreceptor having a multilayer structure can be used. As the material of the photoconductor, an inorganic photoconductor such as selenium or amorphous silicon, an organic photoconductor, or the like can be considered.

  Examples of the charging means 14 include a contact charging device using a conductive or semiconductive roll, brush, film, rubber blade, etc., a non-contact type charging device such as corotron charging or scorotron charging using corona discharge, etc. Any known means can be used.

As the electrostatic latent image forming means 16, in addition to the exposure means, any conventionally known means capable of forming a signal capable of forming a developed image at a desired position on the surface of the transfer material can be used. it can.
As the exposure means, for example, a conventionally known exposure means such as a combination of a semiconductor laser and a scanning device, a laser scanning writing device comprising an optical system, or an LED head can be used. In order to realize a preferable mode of producing a uniform and high-resolution exposure image, it is preferable to use a laser scanning writing device or an LED head.

  Specifically, as the transfer unit 20, for example, a conductive or semiconductive roll, a brush, a film, a rubber blade, or the like to which a voltage is applied may be used between the latent image holding member 12 and the transfer target member 50. A charged toner particle is formed by corona charging the back surface of the transfer object 50 by means for creating an electric field and transferring a developed image composed of charged toner particles, a corotron charger using a corona discharge, or a scorotron charger. Conventionally known means such as means for transferring a developed image consisting of the above can be used.

  A secondary transfer unit can also be used as the transfer unit 20. That is, although not shown, the secondary transfer unit is a unit that transfers the developed image to the intermediate transfer member and then secondary-transfers the transfer image from the intermediate transfer member to the transfer target 50.

  Examples of the cleaning unit 22 include a cleaning blade and a cleaning brush.

  Examples of the static eliminating unit 24 include a tungsten lamp and an LED.

  The transfer target 50 is not particularly limited, and conventionally known ones such as plain paper and glossy paper can be used. Moreover, what has a base material and the image receiving layer formed on the base material can also be utilized for a to-be-transferred body.

  Further, the developing means 18 forms a thin layer of toner on the developer holding member (rotating cylindrical body) by a layer regulating member such as an elastic blade, conveys it to the developing unit, and develops the developing roll and the electrostatic latent image. A latent image holding body that holds the toner image is disposed in contact with the developing unit or with a predetermined gap, and the electrostatic latent image is developed with toner while applying a bias between the developing roll and the latent image holding body. Preferably it is a means.

Next, image formation using the image forming apparatus 10 will be described. First, as the latent image holding body 12 rotates in the direction of arrow A, the surface of the latent image holding body 12 is charged by the charging unit 14 (charging process), and an electrostatic latent image is formed on the charged latent image holding body 12 surface. An electrostatic latent image corresponding to the image information is formed by means 16 (electrostatic latent image forming step).
On the other hand, the electrostatic latent image is developed by the developing means 18 (developing step).

  Next, the developed image formed on the surface of the latent image holding body 12 moves to the contact portion between the latent image holding body 12 and the transfer unit 20 as the latent image holding body 12 rotates in the direction of arrow A. At this time, the latent image holding member 50 is passed through the contact portion by the voltage applied between the latent image holding member 12 and the transfer means 20 when the transfer target member 50 is inserted in the direction of arrow C by a paper conveyance roll (not shown). The developed image formed on the surface 12 is transferred to the surface of the transfer target 50 at the contact portion (transfer process).

  The toner remaining on the surface of the latent image holding member 12 after the developed image is transferred to the transfer unit 20 is removed by the cleaning blade of the cleaning unit 22 (cleaning step), and the charge is removed by the charge removing unit 24.

  The transferred object 50 having the developed image transferred onto the surface in this way is conveyed to the pressure contact portion 32 of the fixing unit 26 and is passed through the pressure contact portion 32 by a built-in heating source (not shown). The surface of the pressure contact portion 32 is heated by the heated fixing means 26. At this time, an image is formed by fixing the transfer image on the surface of the transfer target 50.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

<Preparation of each dispersion>
(Preparation of amorphous polyester resin particle dispersion (1))
-310 parts of bisphenol A propylene oxide 2 mol adduct-116 parts of terephthalic acid-12 parts of fumaric acid-54 parts of dodecenyl succinic acid-0.05 part of Ti (OBu) ₄ After the above raw materials were put into a heat-dried three-necked flask, The air in the container was depressurized by a depressurization operation, and was further brought into an inert atmosphere with nitrogen gas, and refluxed at 180 ° C. for 5 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 240 ° C. while distilling off the water produced in the reaction system by vacuum distillation. Further, the dehydration condensation reaction was continued at 240 ° C. for 3 hours. When the mixture became viscous, the molecular weight was confirmed by GPC. When the weight average molecular weight reached 27000, the vacuum distillation was stopped and the amorphous polyester resin (1 ) The amorphous polyester resin (1) was amorphous, and had a glass transition point of 63 ° C. and an acid value of 14 mgKOH / g. In the present invention, “Bu” represents “butyl”.

  Next, 100 parts of this amorphous polyester resin (1), 50 parts of ethyl acetate, 25 parts of isopropyl alcohol, and 5 parts of 10% ammonia aqueous solution were put into a separable flask, mixed sufficiently, dissolved, and then heated to 40 ° C. Then, ion-exchanged water was added dropwise at a liquid feed rate of 8 g / min using a liquid feed pump while stirring with heating. After the liquid became cloudy, the liquid feeding speed was increased to 25 g / min to cause phase inversion, and dropping was stopped when the liquid feeding amount reached 135 parts. Thereafter, the solvent was removed under reduced pressure to obtain an amorphous polyester resin particle dispersion (1). The obtained polyester resin particles had a volume average particle size of 132 nm and the polyester resin particles had a solid content concentration of 34%.

(Preparation of amorphous polyester resin particle dispersion (2))
-310 parts of bisphenol A propylene oxide 2 mol adduct-116 parts of terephthalic acid-12 parts of fumaric acid-54 parts of dodecenyl succinic acid-0.05 part of Ti (OBu) ₄ After the above raw materials were put into a heat-dried three-necked flask, The air in the container was depressurized by a depressurization operation, and was further brought into an inert atmosphere with nitrogen gas, and refluxed at 180 ° C. for 5 hours with mechanical stirring. Thereafter, the temperature was gradually raised to 240 ° C. while distilling off the water produced in the reaction system by vacuum distillation. Further, the dehydration condensation reaction was continued at 240 ° C. for 2 hours, and when it became viscous, the molecular weight was confirmed by GPC. When the weight average molecular weight reached 36000, the vacuum distillation was stopped and the amorphous polyester resin (2 ) Amorphous polyester resin (2) was amorphous and had a glass transition point of 65 ° C. and an acid value of 14 mgKOH / g. Further, an amorphous polyester resin particle dispersion (2) was prepared in the same manner as the preparation of the amorphous polyester resin particle dispersion (1).

(Preparation of crystalline polyester resin particle dispersion)
In a heat-dried three-necked flask, 230 parts of 1,10-dodecanedioic acid, 160 parts of 1,9-nonanediol, and 0.2 part of dibutyltin oxide as a catalyst were added, and then the air in the three-necked flask was removed by depressurization. The reaction was allowed to proceed under an inert atmosphere by replacing with nitrogen at 180 ° C. for 5 hours by mechanical stirring and refluxing. During the reaction, water produced in the reaction system was distilled off. Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and when the mixture became viscous after stirring for 2 hours, the molecular weight was confirmed by GPC. When the weight average molecular weight reached 29000, the distillation under reduced pressure was stopped and the crystals A functional polyester resin was obtained. The melting point of the crystalline polyester resin was 73 ° C., and the acid value was 12 mgKOH / g.

  Next, 100 parts of this crystalline polyester resin, 35 parts of ethyl acetate, and 35 parts of isopropyl alcohol are placed in a separable flask and thoroughly mixed and dissolved at 75 ° C. Then, 5.5 parts of a 10% aqueous ammonia solution is added dropwise. did. The heating temperature is lowered to 60 ° C., and ion-exchanged water is added dropwise with stirring using a liquid feed pump at a liquid feed speed of 6 g / min. After the liquid becomes cloudy, the liquid feed speed is increased to 25 g / min. When the amount reached 400 parts, dropping of ion-exchanged water was stopped. Thereafter, the solvent was removed under reduced pressure to obtain a crystalline polyester resin particle dispersion. The obtained crystalline polyester resin particles had a volume average particle size of 136 nm and the polyester resin particles had a solid content concentration of 17%.

(Preparation of release agent dispersion (1))
-FNP92 (Nippon Seiki Co., Ltd.) 50 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 5 parts-Ion-exchanged water 200 parts IKA Co., Ltd .: Ultra Turrax T50), and then dispersed with a Manton Gorin high-pressure homogenizer (Gorin Co., Ltd.) to give a release agent having an average particle size of 0.24 μm and a melting point of 92 ° C. A release agent dispersion liquid (1) having a release agent concentration of 23% was prepared by dispersing.

(Preparation of silica particle dispersion (1))
・ R805 (Aerosil Co., Ltd .: primary particle size 16 nm) 50 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK) 5 parts ・ Ion-exchanged water 150 parts After mixing the above with a stirrer Then, a silica particle dispersion (1) having a silica concentration of 24% was prepared by dispersing with an ultrasonic disperser.

(Preparation of colorant dispersion (1))
・ Cyan pigment (Dai-Ni Seika Co., Ltd., CI Pigment Blue 15: 3, (copper phthalocyanine)) 100 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R) 15 parts ・ Ion exchange Disperse the colorant by mixing 900 parts or more of water, dissolving, and dispersing for 1 hour using a high-pressure impact disperser Ultimateizer (manufactured by Sugino Machine Co., Ltd., HJP30006) to disperse the colorant (cyan pigment). A liquid was prepared. The average particle diameter of the colorant (cyan pigment) in the colorant dispersion was 0.13 μm, and the colorant particle concentration was 25%.

(Preparation of colorant dispersion (2))
・ Carbon black R330 (Cabot) 100 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen R) 15 parts ・ Ion-exchanged water 900 parts A colorant dispersion 2 was prepared by dispersing the colorant (carbon black pigment) by dispersing for 1 hour using HJP30006 (manufactured by Sugino Machine Co., Ltd.). The average particle diameter of the colorant (carbon black pigment) in the colorant dispersion was 0.13 μm, and the colorant particle concentration was 25%.

(Production of Toner (1))
In a polymerization kettle equipped with a pH meter, a stirring blade, and a thermometer, among the above raw materials, 758 parts of amorphous polyester resin particle dispersion (1), 180 parts of crystalline polyester resin particle dispersion (1), anion 32 parts of a surfactant (dowfax2A1, 20% aqueous solution) and 1278 parts of ion-exchanged water are added, and the surfactant is mixed with the amorphous polyester resin particle dispersion (1) while stirring at 200 rpm for 15 minutes. It was. After further stirring and letting it fully blend, 120 parts of the colorant dispersion (1) and 201 parts of the release agent dispersion (1) were added and mixed, and then a 0.3M nitric acid aqueous solution was added to the raw material mixture. The pH was adjusted to 2.7. Next, 250 parts of an aqueous 10% aluminum sulfate solution was added dropwise as a flocculant while applying a shearing force at 1000 rpm with Ultraturrax (manufactured by IKA Japan). In addition, since the viscosity of the raw material mixture increases during the dropping of the flocculant, the dropping speed was reduced when the viscosity increased, so that the flocculant was not biased to one place. When the dropping of the flocculant was completed, the rotational speed was further increased to 6000 rpm and the mixture was stirred for 5 minutes to sufficiently mix the flocculant and the raw material mixture.

  Subsequently, the raw material mixture was stirred at 550 to 650 rpm while being heated to 30 ° C. with a mantle heater. After stirring for 60 minutes, it was confirmed that the primary particle size was stably formed using Multisizer II type (aperture diameter: 50 μm, manufactured by Beckman-Coulter), and then 0.5 ° C / The temperature was raised to 45 ° C in minutes. The growth of the agglomerated particles is confirmed at any time using Multisizer II type, and the agglomeration temperature and the number of rotations of stirring are changed depending on the agglomeration speed.

  On the other hand, 145 parts of ion-exchanged water and 15 parts of an anionic surfactant (dowfax2A1, 20% aqueous solution) are added to 411 parts of the amorphous polyester resin dispersion (1) for coating the aggregated particles. A coating resin particle dispersion (1) adjusted to pH 2.7 was prepared. When the aggregated particles grew to 5.0 μm in the aggregation step, the coating resin particle dispersion (1) was added and held for 10 minutes with stirring. Thereafter, in order to stop the growth of the coated aggregated particles (adherent particles), 33 parts of an EDTA aqueous solution (Kyles 40 manufactured by Kires Co., Ltd. diluted to 12% concentration with ion-exchanged water) and a 1M aqueous sodium hydroxide solution were sequentially added. In addition, the pH of the raw material mixture was controlled at 7.5. Subsequently, in order to fuse the aggregated particles, the temperature was raised to 85 ° C. at a temperature raising rate of 1 ° C./min while adjusting the pH to 6.5. After confirming that the aggregated particles were fused with an optical microscope, ice water was injected and rapidly cooled at a cooling rate of 100 ° C./min.

  Next, the pH of the slurry after cooling the obtained particles with 1N aqueous sodium hydroxide solution was adjusted to 9.0, stirred for 20 minutes, and sieved once with a 20 μm mesh. Thereafter, approximately 10 times the amount of warm water (50 ° C.) was added to the solid content, and the mixture was stirred for 20 minutes while adjusting the pH to 9.0 again, washed with warm alkali, and once filtered. Further, the solid content remaining on the filter paper is dispersed in the slurry and washed three times with 40 ° C. warm water, and further washed with acid at 40 ° C. while adding a 0.3N nitric acid aqueous solution to the slurry to 4.0. went. Then, finally, the mixture was washed with stirring at 40 ° C. in ion-exchanged water and dried to obtain toner base particles (A1) having a volume average particle size of 6.6 μm.

  To the toner base particles (A1) obtained above, silica fine powder (particle diameter: 50 nm) and titania fine powder (particle diameter: 40 nm) as external additives were added in an amount of 0.9 parts with respect to 100 parts of the toner base particles. And 0.6 part were added and mixed with a Henschel mixer to obtain toner (1).

(Production of Toner (2))
In a polymerization kettle equipped with a pH meter, a stirring blade, and a thermometer, among the above raw materials, 698 parts of amorphous polyester resin particle dispersion (1), 213 parts of silica particle dispersion (1), anionic surface activity 32 parts of an agent (dowfax 2A1, 20% aqueous solution) and 1305 parts of ion-exchanged water were added, and the surfactant was blended with the amorphous polyester resin particle dispersion (1) while stirring at 200 rpm for 15 minutes. After further stirring and letting it sufficiently blend, 120 parts of the colorant dispersion and 201 parts of the release agent dispersion (1) were added and mixed, and then a 0.3 M nitric acid aqueous solution was added to the raw material mixture to adjust the pH. Was adjusted to 2.7. Next, 250 parts of an aqueous 10% aluminum sulfate solution was added dropwise as a flocculant while applying a shearing force at 1000 rpm with Ultraturrax (manufactured by IKA Japan). In addition, since the viscosity of the raw material mixture increases during the dropping of the flocculant, the dropping speed was reduced when the viscosity increased, so that the flocculant was not biased to one place. When the dropping of the flocculant was completed, the rotational speed was further increased to 6000 rpm and the mixture was stirred for 5 minutes to sufficiently mix the flocculant and the raw material mixture.
Thereafter, aggregation, temperature rise, coalescence, washing and drying were performed in the same manner as the toner base particles (A1), and toner particles (A2) having a volume average particle size of 6.4 μm were obtained.

  To the toner base particles (A2) obtained above, silica fine powder (particle diameter: 50 nm) and titania fine powder (particle diameter: 40 nm) as external additives were added in an amount of 0.9 parts with respect to 100 parts of the toner base particles. And 0.6 part were added and mixed with a Henschel mixer to obtain toner (2).

(Production of toners (3), (6), (8))
The production of toner (1) was the same as the production of toner (1) except that the amount of the crystalline polyester resin particle dispersion used was changed so that the composition of the crystalline polyester resin would be the value shown in Table 1. Thus, toners (3), (6), and (8) were produced.

(Production of toners (4) and (9))
In the preparation of the toner (2), the type of the colorant dispersion is changed to the dispersion shown in Table 1, and the amount of the silica particle dispersion used is adjusted so that the composition of the silica particles becomes the value shown in Table 1. Toners (4) and (9) were produced in the same manner as in the production of toner (2), except for the changes.

(Production of Toner (5))
In preparation of the toner (1), the amorphous polyester particle dispersion (1) was changed to the amorphous polyester particle dispersion (2), and the colorant dispersion (1) was changed to the colorant dispersion (2). A toner (5) was obtained in the same manner as in the preparation of the toner (1) except for the above.

(Production of Toner (7))
A toner (7) was prepared in the same manner as in the preparation of the toner (1) except that the crystalline polyester resin particle dispersion (1) was not used in the preparation of the toner (1).

  Table 1 shows the volume average particle diameter of each of the obtained toners (1) to (9), the peak temperature of tan δ, the peak value of tan δ, and the tan δ value at a temperature at which G ″ = 100,000 Pa.

(Development of developer and evaluation method)
Two parts of each of the obtained toners (1) to (9) and 100 parts of resin-coated ferrite particles (volume average particle diameter 35 μm) are mixed to prepare two-component developers (1) to (9). Each was produced.

<Example 1>
Using the developer (1), the following image was formed by the image forming apparatus having the same configuration as that shown in FIG. 2 and having the fixing device (fixing means) having the same configuration as that shown in FIG. . In the image forming apparatus, the surface layer 613 of the fixing roll of the fixing device is made of PFA in which silicon carbide (content 7% in the surface layer 613) as an anti-wear additive is dispersed. The thickness is 30 microns, and the thickness of the rubber elastic layer 612 is 200 μm.

The evaluation was performed using an electrophotographic copying machine (Docu Center Color a450, manufactured by Fuji Xerox Co., Ltd.) with a modified fixing device (fixing device), and a half-size image with a 50% image density on A4 plain paper (P paper manufactured by Fuji Xerox Co., Ltd.). After 150,000 continuous double-sided copies of the tone image, 10 full-surface halftone images with an image density of 50% shown in FIG. 3A were continuously copied. The hot offset occurrence at this time was observed and visually evaluated according to the following criteria. . The results are shown in Table 2. Also, the image of the solid tip image (image density 100%) shown in FIG. 3B was observed, and the situation is shown in Table 2.
A: Very little.
○: Less (a level at which there is no problem in the image).
X: Many.
XX: Very many.

<Examples 2-9, Comparative Examples 1-7>
In Example 1, the type, volume average particle size, content, and thickness of the rubber elastic layer 612 in the surface layer 613 of the fixing roll of the fixing device were changed as shown in Table 2, and further, Except that the type of developer was changed as shown in Table 2, the hot offset occurrence state and the image defect were evaluated in the same manner as in Example 1. In Examples 4, 5, and 7 and Comparative Example 4, the rubber elastic layer 612 was not provided. The results are shown in Table 2. Table 2 also shows the tan δ peak temperature, the tan δ peak value of the toner contained in the developer used, and the tan δ value at a temperature at which G ″ = 100,000 Pa.

  From Table 2, it can be seen that Examples 1 to 9 have good evaluation of the occurrence status of hot offset, and the problem that the life of the fixing member can be extended without causing offset is achieved.

It is a schematic block diagram which shows an example of the heat fixing apparatus in this invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a figure which shows the image used for experiment. It is a figure which shows the image used for experiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 12 ... Electrostatic latent image holding body 14 ... Charging means 16 ... Electrostatic latent image forming means 18 ... Developing means 20 ... Transfer means 60 ... Fixing device 61 ... Fixing roll 62 ... Endless belt 63 ... Belt running guide 64 ... pressure pad 64a ... pre-contact member 64b ... peeling contact member,
65 ... Holder 66 ... Halogen lamp,
67 ... Lubricant application member 68 ... Low friction sheet 69 ... Temperature sensor 70 ... Release member 611 ... Metal roll 612 ... Elastic layer 613 ... Fixing roll surface layer N ... Contact part

Claims (8)

An electrostatic latent image forming step of forming an electrostatic latent image on the latent image holding member; and a developing step of developing the electrostatic latent image formed on the latent image holding member as a developed image with a developer containing toner; A transfer step of transferring the developed image formed on the latent image holding member onto the transfer member; and a fixing step of fixing the transfer image transferred onto the transfer member;
The fixing step uses a fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle diameter of 1 μm or less is dispersed and a pressure member to transfer a transfer image transferred onto the transfer target. Fixing process,
The toner has an tan δ peak in a range of 40 ° C. or higher and 70 ° C. or lower in dynamic viscoelastic temperature dependency measurement, and the peak value is less than 2.0. .   The image forming method according to claim 1, wherein the wear-resistant additive is carbon black or silicon carbide. The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0.15 mm or more and less than 4 mm,
3. The toner according to claim 1, wherein the toner has a tan δ value of 1.7 or more and less than 3.5 at a temperature at which G ″ = 100,000 Pa in measurement of dynamic viscoelastic temperature dependency. The image forming method described in 1. The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0 mm or more and less than 0.15 mm,
3. The toner according to claim 1, wherein the toner has a tan δ value of 0.5 or more and less than 1.7 at a temperature at which G ″ = 100,000 Pa in dynamic viscoelastic temperature dependency measurement. The image forming method described in 1. A latent image holding member, an electrostatic latent image forming unit for forming an electrostatic latent image on the surface of the latent image holding member, and developing the electrostatic latent image formed on the latent image holding member with a developer containing toner. Developing means for developing as an image, transfer means for transferring the developed image formed on the latent image holding member onto the transfer member, and fixing means for fixing the transfer image transferred onto the transfer member; With
The fixing unit includes a fixing member having a surface layer in which an abrasion-resistant additive having a volume average particle diameter of 1 μm or less is dispersed, and a pressure member.
The toner has an tan δ peak in a range of 40 ° C. or higher and 70 ° C. or lower in dynamic viscoelastic temperature dependence measurement, and the peak value is less than 2.0. .   The image forming apparatus according to claim 5, wherein the wear-resistant additive is carbon black or silicon carbide. The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0.15 mm or more and less than 4 mm,
7. The toner according to claim 5, wherein the toner has a tan δ value of 1.7 or more and less than 3.5 at a temperature at which G ″ = 100,000 Pa in the measurement of dynamic viscoelastic temperature dependency. The image forming apparatus described in 1. The surface layer of the fixing member is formed on a rubber elastic layer having a thickness of 0 mm or more and less than 0.15 mm,
7. The toner according to claim 5, wherein the toner has a tan δ value of 0.5 or more and less than 1.7 at a temperature at which G ″ = 100,000 Pa in the measurement of dynamic viscoelastic temperature dependency. The image forming apparatus described in 1.

Images