JP2006030806A - Dry electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry electrophotographic toner excellent in charging property, conveyability, developing performance, transferability and storage stability and free of occurrence of an abnormal image due to adhesion to a photoreceptor, and to provide a developer, a developing device and an image forming method. <P>SOLUTION: The toner includes a polyester resin, as a binder, free from a THF-insoluble component, containing ≤4 wt.% of a component ≤5×10<SP>2</SP>mol.wt. and having a main peak in a region of 3×10<SP>3</SP>-9×10<SP>3</SP>weight mol.wt., a metal salt compound of salicylic acid or a salicylic acid derivative as a charge control agent, and hydrophobed silica having a primary particle diameter of 0.01-0.03 μm and hydrophobed titanium oxide having a primary particle diameter of 0.01-0.03 μm and a specific surface area of 60-140 m<SP>2</SP>/g as additives, wherein the titanium oxide is produced by a wet process, contains ≥0.2 wt.% of a water-soluble component and has specified transmittance at 300 nm and 600 nm in a UV absorption method. The toner is manufactured while reusing a by-product obtained from a pulverizing step or a classifying step in a melt kneading step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, and an electrophotographic developing apparatus using the toner. More particularly, the present invention relates to an electrophotographic toner, an electrophotographic developer, and an electrophotographic developing apparatus used for a copying machine, a laser printer, a plain paper fax machine, and the like using a direct or indirect electrophotographic developing system. In addition, full-color copiers, full-color laser printers using direct or indirect electrophotographic multicolor image development systems, electrophotographic toners, electrophotographic developers, electrophotographic developing apparatuses and process cartridges used in full-color plain paper fax machines, etc. About.

  In the developing process, a developer used in electrophotography, electrostatic recording, electrostatic printing, and the like is once attached to an image carrier such as a photoreceptor on which an electrostatic charge image is formed, and then in a transfer process. After being transferred from the photoreceptor to a transfer medium such as transfer paper, it is fixed on the paper surface in a fixing step. At that time, as a developer for developing the electrostatic image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner, and a one-component developer that does not require a carrier (magnetic toner, Non-magnetic toners are known. In the two-component development method, the developer deteriorates due to the toner particles adhering to the carrier surface, and since only the toner is consumed, the toner concentration in the developer decreases, so the mixing ratio with the carrier is kept constant. Therefore, the developing device is relatively large. On the other hand, in the one-component development system, the size of the apparatus has been further reduced due to the higher functionality of the developing roller and the like.

  In recent years, office automation and colorization have further progressed in offices, and not only copying originals consisting only of conventional characters, but also pictorials read from graphs created with personal computers, images taken with digital cameras, scanners, etc. Opportunities are increasing to output a manuscript or the like with a printer and to make a large number of copies as presentation materials. A printer output image has a complicated configuration mixed in one original such as a solid image, a line image, and a halftone image, and various demands are increasing along with a demand for high reliability of the image.

  Conventional electrophotographic processes using a one-component developer are classified into a magnetic one-component developing method using magnetic toner and a non-magnetic one-component developing method using non-magnetic toner. In the magnetic one-component development method, a developer carrying member provided with a magnetic field generating means such as a magnet is used to hold a magnetic toner containing a magnetic material such as magnetite, and a thin layer is developed by a layer thickness regulating member. In recent years, many have been put into practical use in small printers and the like. However, the magnetic material has a disadvantage that it is colored, and many are black and difficult to color.

  In contrast, in the non-magnetic one-component development method, since the toner does not have a magnetic force, a toner replenishing roller or the like is pressed against the developer carrying member to supply the toner onto the developer carrying member and electrostatically hold the layer. The film is developed with a thin layer by a thickness regulating member. This has the advantage that it does not contain a colored magnetic material and can be used for colorization. Furthermore, since no magnet is used for the developer carrier, the device can be further reduced in weight and cost. It has been put to practical use.

  On the other hand, in the two-component development method, a carrier is used as a means for charging and transporting toner, and after the toner and carrier are sufficiently stirred and mixed in the developing device, the toner is transported to the developer carrier and developed, so that it takes a relatively long time. Even in use, it is possible to maintain stable chargeability and transportability, and it is easy to cope with high-speed developing devices.

  Compared to this, there are still many problems to be improved in the one-component development method. In the one-component development system, since there is no stable charging or conveying means like a carrier, charging failure and conveyance failure are likely to occur due to long-term use and high speed. That is, in the one-component development method, after the toner is transported onto the developer carrier, the toner is thinned by the layer thickness regulating member and developed, but the friction between the toner and the developer carrier, the layer thickness regulating member, etc. Since the contact time with the charging member and the frictional charging time are very short, the amount of low-charged and reverse-charged toner tends to increase more than the two-component development method using a carrier.

  In particular, in the non-magnetic one-component developing method, means for developing a latent electrostatic image formed on a latent image carrier by conveying toner (developer) usually by at least one toner conveying member and by the conveyed toner. In this case, the thickness of the toner layer on the surface of the toner conveying member must be as thin as possible. This is also true when a two-component developer with a very small carrier is used, and particularly when a one-component developer is used and the toner has a high electrical resistance. Since the toner needs to be charged by the developing device, the toner layer thickness must be remarkably reduced. This is because if the toner layer is thick, only the surface of the toner layer is charged, and the entire toner layer is difficult to be uniformly charged. For this reason, the toner is required to maintain a faster charging speed and an appropriate charge amount.

Therefore, in order to stabilize the charging of the toner, a charge control agent and an additive have been added.
The charge control agent functions to control the triboelectric charge amount of the toner and maintain the triboelectric charge amount. Typical negative charge control agents include monoazo dyes, salicylic acid, naphthoic acid, dicarboxylic acid metal salts / metal complex salts, diazo compounds, complex compounds with boron, etc. Examples of the charge control agent include quaternary ammonium salt compounds, imidazole compounds, nigrosine, and azine dyes.

  However, some of these charge control agents have a chromatic color, and many cannot be used for color toners. In addition, some of these charge control agents have poor compatibility with the binder resin, so that those present on the surface of the toner that are greatly involved in charging are easily detached, resulting in variations in toner charging. There is a drawback that the developing sleeve is easily contaminated and the photosensitive member filming is likely to occur. For this reason, in the prior art, a good image can be obtained in the initial stage, but the image quality gradually changes, causing a phenomenon that background stains and blurring occur. In particular, when applied to color copying and continuously used while replenishing toner, the amount of toner charge is reduced, resulting in an image that differs significantly from the color tone of the initial copied image, and it cannot withstand long-term use. The image forming unit called a process cartridge has to be replaced at an early stage only by copying to a certain extent. For this reason, the load on the environment is large, and it takes time and effort for the user. Furthermore, since many of these cartridges contain heavy metals such as chrome, they have recently become a problem from the viewpoint of safety.

In recent years, the demand for printers has increased, and the size, speed, and cost of the devices have been increasing. As a result, higher reliability and longer life have been demanded for the devices. However, with these resin charge control agents, the charge control effect cannot be maintained, and the developing sleeve and the layer thickness regulating member (blade and roller) are contaminated, so that the charging performance of the toner is reduced, and the photoconductor filming is performed. There was a problem.
In addition, a process that develops in a short time with a small amount of developer due to downsizing and speeding up, and a developer with better charge rise is demanded. Regarding development, various development methods have been proposed for both two-component and one-component developers, but it is excellent in that it can be reduced in size and weight, and non-magnetic one-component development that eliminates the need for carriers is used for printers. Is suitable. In this developing system, the toner replenishment property to the developing roller and the toner retaining property of the developing roller are poor, so the toner is forcibly rubbed against the developing roller or the amount of toner on the developing roller is regulated by a blade. As a result, the toner tends to film on the developing roller, resulting in a problem that the life of the developing roller is shortened and the charge amount of the toner becomes unstable. This also prevents good development. Therefore, in color toners for non-magnetic one-component development, in addition to the characteristics required for general color toners, the heat resistance of the binder resin used for the toner is often inferior, and the toner on the developing roller is often inferior. Filming is likely to occur.

Patent Document 1 discloses that a metal complex of salicylic acid or salicylic acid is used as a charge control agent. However, the intended charge stability cannot be obtained, and environmental fluctuation is poor. Patent Document 2 discloses a toner containing a saturated or unsaturated fatty acid metal salt having 8 to 35 carbon atoms. However, if the number of carbon atoms is less than 16, an increase in reversely charged toner, deterioration of background stains, and the like may occur. This produces a lubricant effect.
In addition to the function of controlling and maintaining the triboelectric charge amount of the toner, the additive has functions such as toner transportability, developability, transferability, and storage stability.
In order to improve these characteristics, for example, it is disclosed that hydrophobic silica is added to the toner (see Patent Documents 3 and 4). However, the chargeability of silica alone is too high, and the transferability is good. This causes defects such as dust and scattering.
Further, it is disclosed that titanium oxide particles surface-treated with titanium oxide or a coupling agent are added to the toner (see Patent Documents 5 and 6), but sufficient chargeability and fluidity can be obtained with titanium oxide alone. In other words, it was found that the particle size is large and the particles are easily agglomerated, so that they are not uniformly adhered to the toner and cause an abnormal image.
Patent Document 7 discloses surface-treated fine particle titanium oxide, but although the dispersibility of the particles has been improved, a sufficient amount of charge has not been obtained by itself. On the other hand, when this titanium oxide is used in combination with silica, the charge amount increases with time.
Patent Documents 8 and 9 disclose that hydrophobic silica and hydrophobic titanium oxide are used in combination, but due to the combination of highly hydrophobic additives, the amount of charge increases over time, and transfer It may cause a defect.

Japanese Patent Laid-Open No. 55-42752 Japanese Patent Laid-Open No. 10-221878 JP 56-128956 A JP 59-52255 A JP 60-112052 A JP-A-4-40467 Japanese Patent No. 3322858 JP 7-43930 A Japanese Patent No. 3160688

  It is an object of the present invention to stably control and maintain the triboelectric charge amount of toner, to maintain stable triboelectric chargeability with little environmental fluctuation, and to convey toner, developability, and transfer. It is an object of the present invention to provide a dry electrophotographic toner and developer, a developing apparatus using the same, an image forming method, and a process cartridge, which are excellent in storage property and storage stability and do not cause abnormal images due to adhesion to a photoreceptor.

  As a result of diligent investigations to solve the above-mentioned problems, the present inventors have found that a charge having a specific component and component ratio with respect to a polyester resin that is suitable as a binder resin for a full-color toner in terms of color developability and image strength. When a control agent, specific surface-treated titanium oxide, and silica are used, a high charge amount and a sharp charge amount distribution are obtained. Furthermore, it is possible to prevent contamination of the developing carrier (developing roller or sleeve) and developing layer thickness regulating member (blade or roller) and photoconductor filming over a long period of tens of thousands of sheets, and it has good crushability and high productivity. The present inventors have found that an electrophotographic toner, a developer, and an image forming method can be obtained.

That is, the above-mentioned problem is (1) “a dry electrophotographic toner having at least a binder resin, a colorant, a charge control agent, and other additives as main components in the present invention. The polyester resin does not contain a THF-insoluble component, and the content ratio of the component having a molecular weight of 5 × 10 ² or less in the molecular weight distribution by gel permeation chromatography is 4% by weight or less, and the weight molecular weight is 3 × 10 ³ to It has a main peak in a region of 9 × 10 ^3, the charge control agent is made of a metal salt compound of salicylic acid or a salicylic acid derivative, and the additive is hydrophobized to a primary particle size of 0.01 to 0.03 μm. Silica and hydrophobized titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g; The titanium oxide fine particles having a water-soluble component amount of 0.2% by weight or more produced by a wet method, and having a transmittance of 300% or more in a UV absorption method at a wavelength of 300 nm, and The transmittance of 600 nm is 80% or more, and the dry electrophotographic toner is a step of mechanically mixing a binder resin, a coloring material and a charge control agent among the main components, a step of heating and melting, a rolling cooling and pulverization A dry electrophotographic toner characterized by reusing a by-product obtained from a pulverization step or a classification step of a production method comprising a step of mixing, a step of mixing, and a step of mixing additives into a melt-kneading step ", ( 2) “Dry electrophotographic toner according to item (1), wherein the binder resin has an endothermic peak in DSC in the range of 60 to 70 ° C.”, (3 “The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the binder resin is 2 ≦ Mw / Mn ≦ 10, wherein the (1) or (2 The dry electrophotographic toner according to item (1), (4) (1) to (3), wherein the binder resin has an acid value of 10 KOHmg / g or less. (5) “The temperature at which the apparent viscosity of the binder resin by a flow tester is 10 ³ Pa · s is 95 to 120 ° C.” (4) The dry electrophotographic toner according to any one of (4) and (6), wherein the charge control agent is contained in an amount of 0.1 to 10% by weight based on toner particles. Item 1) to Item (5) (7) “2.1 parts by weight or more of silica having a primary particle diameter of 0.01 to 0.03 μm hydrophobized with respect to 100 parts by weight of the base toner. Item (1) above, comprising 0.4 to 1.0 part by weight of hydrophobized titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g. To a dry electrophotographic toner according to any one of Items (6) to (6).
Further, the above-mentioned problems are (8) “dry one-component developer comprising the dry electrophotographic toner described in (1) above”, (9) “(1) above”. And a dry two-component developer characterized by comprising a dry electrophotographic toner described in 1) and a carrier.
Further, the above-mentioned problems are solved by (10) “a latent image forming step of forming a latent image on a latent image holding member, a developing step of developing the latent image using a developer on a developer carrying member,” The dry one-component development according to claim 8, wherein the developing step includes a developing step of transferring the toner image onto the transfer body and a fixing step of heating and fixing the toner image on the transfer body as a developer. Image forming method characterized by using an agent ”, (11)“ Latent image forming step of forming a latent image on a latent image holding member, and using the developer on the developer carrying member as the latent image ” In the image forming method, the image forming method includes a developing step of developing the toner image, a transferring step of transferring the developed toner image onto the transfer member, and a fixing step of heating and fixing the toner image on the transfer member. (9) Uses the dry two-component developer described in item 9. Is achieved by the image forming method ", wherein Rukoto.
In addition, the above-described problems are solved by (12) “a container for holding a one-component developer according to item (8), a container for supplying the developer, and a latent image forming unit for forming the latent image. A developing unit for developing the latent image with a developer, a transfer unit for transferring the developed toner image onto a transfer member onto a transfer member, and a transfer unit for transferring the transfer image. An image forming apparatus comprising: a container for holding a dry two-component developer according to item (9), a container for replenishing the toner, and a latent image. Latent image forming means, developing means for developing the latent image with a developer, transfer means for transferring the developed toner image onto a transfer member onto a transfer member, transfer for transferring the transfer image An image forming apparatus characterized by having an apparatus having means ", ( 4) “Image formation according to item (12) or (13), wherein the developing means for developing the latent image on the latent image holding member has an alternating electric field applying means for applying an alternating electric field. Achieved by "device".
Further, the above-described problem is (15) in the process cartridge according to the present invention, in which the photosensitive member and at least one means selected from the charging means, the developing means, and the cleaning means are integrally supported and detachable from the image forming apparatus main body. The developing means holds toner or developer, and the toner or developer is the toner according to any one of the items (1) to (7) or the item (8) or (9). (16) “The fixing means includes a heating body including a heating element, a film in contact with the heating body, and the heating via the film. A fixing device that includes a pressure member that is in pressure contact with a body, and that heats and fixes a recording material on which an unfixed image is formed between the film and the pressure member. 11) is achieved by claim or (13) an image forming apparatus according to any one of Items ".

  As will be apparent from the following detailed and specific description, according to the present invention, specific constituent components and composition ratios of a polyester resin suitable as a binder resin for a full-color toner from the viewpoint of color developability and image strength. By using a charge control agent, specific surface-treated titanium oxide, and silica, a high charge amount and a sharp charge amount distribution can be obtained. In addition, it is possible to prevent contamination of the developing carrier (developing roller or sleeve) and developing layer thickness regulating member (blade or roller) and photoconductor filming over a long period of tens of thousands or more. High electrophotographic toner, developer and image forming method can be obtained, the triboelectric charge amount of toner can be stably controlled and maintained, and stable with little environmental fluctuation Dry electrophotographic toner and developer capable of maintaining high triboelectric chargeability, excellent toner transportability, developability, transferability, and storage stability, and causing no abnormal images due to adhesion to the photoreceptor. It is possible to provide a developing device, an image forming method, and a process cartridge using the toner.

The present invention is described in detail below.
The present invention is a dry electrophotographic toner in which the binder resin is polyester, the charge control agent is a salicylic acid derivative, and includes hydrophobic silica and hydrophobic titanium oxide.
As the binder resin used in the toner of the present invention, a polyester resin suitable as a binder resin for a full color toner is used from the viewpoint of color developability and image strength. In a color image, several types of toner layers are stacked several times, so that the toner layer becomes thick, causing cracks and defects in the image due to insufficient strength of the toner layer, and loss of appropriate gloss. For this reason, a polyester resin is used to maintain an appropriate gloss and excellent strength.

In particular, the binder resin of the present invention has no THF-insoluble content, and in the molecular weight distribution in gel permeation chromatography, the content of components having a weight average molecular weight of 5 × 10 ² or less is 4% by weight or less, and the molecular weight is 3 × 10 ^3. It has one peak in a region of ˜9 × 10 ³ . When THF-insoluble matter enters, the glossiness is lowered and the transparency is lowered, and a high-quality image cannot be obtained when an OHP sheet is used. In the toner of the present invention, the weight average molecular weight of 5 × 10 ² or less is specified for the molecular weight distribution of the binder resin, and the ratio of the weight average molecular weight to the number average molecular weight is specified to provide a blade, sleeve, or the like. Filming is less likely to occur. Further, when the component having a weight average molecular weight of 5 × 10 ² or less exceeds 4% by weight, the blade or sleeve is contaminated by long-term use, and filming is likely to occur.

First, the polyester resin will be described.
A polyester resin that is a binder resin can be generally obtained by an esterification reaction of a polyhydric alcohol and a polycarboxylic acid. Among the monomers constituting the polyester resin in the present invention, examples of the alcohol monomer include trifunctional or higher polyfunctional monomers such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3- Diols such as propylene glycol, 1,4-butadieneol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxypropylene Bisphenol A alkylene oxide adducts such as bisphenol A, other dihydric alcohols, or sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol , Tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, tri Examples thereof include methylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene, and other trihydric or higher polyhydric alcohols.

  Among these monomers constituting the polyester resin, those using a bisphenol A alkylene oxide adduct as a main component monomer are preferably used. When a bisphenol A alkylene oxide adduct is used as a constituent monomer, a polyester having a relatively high glass transition point is obtained due to the nature of the bisphenol A skeleton, and the copy blocking resistance and heat resistant storage stability are good. In addition, the presence of alkyl groups on both sides of the bisphenol A skeleton acts as a soft segment in the polymer, and the color developability and image strength during toner fixing are improved. Of the bisphenol A alkylene oxide adducts, those having an ethylene group or a propylene group are preferably used.

  Among the monomers constituting the polyester resin in the present invention, examples of the acid monomer include trifunctional or higher polyfunctional monomers, such as maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, and isophthalic acid. , Terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, or alkenyl succinic acid such as n-dodecenyl succinic acid, n-dodecyl succinic acid or alkyl succinic acid, anhydrides of these acids Alkyl esters, other divalent carboxylic acids, and 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4- Butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, , 3-dicarboxyl-2-methyl-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, and anhydrides, alkyl esters, alkenyls thereof Examples thereof include esters, aryl esters, and other trivalent or higher carboxylic acids.

  Specific examples of the alkyl ester, alkenyl ester or aryl ester described herein include triethyl 1,2,4-benzenetricarboxylate, trimethyl 1,2,4-benzenetricarboxylate, triethyl 1,2,4-benzenetricarboxylate. 1,2,4-benzenetricarboxylic acid tri-n-butyl, 1,2,4-benzenetricarboxylic acid isobutyl, 1,2,4-benzenetricarboxylic acid tri-n-octyl, 1,2,4-benzenetricarboxylic acid tri 2-ethylhexyl, 1,2,4-benzenetricarboxylic acid tribenzyl, 1,2,4-benzenetricarboxylic acid tris (4-isopropylbenzyl) and the like.

  The production method for obtaining the polyester used in the toner of the present invention is not particularly limited, and the esterification reaction can be carried out by a known method. The transesterification reaction can also be performed by a known method, and a known transesterification catalyst can be used. Examples thereof include magnesium acetate, zinc acetate, manganese acetate, calcium acetate, tin acetate, lead acetate, and titanium tetrabutoxide. The polycondensation reaction can be performed by a known method, and a known polymerization catalyst can be used. Specific examples include antimony trioxide and germanium dioxide.

The molecular weight distribution of the binder resin used in the toner of the present invention is measured by gel permeation chromatography as follows. The column was stabilized in a heat chamber at 40 ° C., and THF was added to the column at this temperature as a solvent at a flow rate of 1 ml / min. 200 μl is measured. Before injecting the THF sample solution, the THF-insoluble components are removed with a 0.45 μm filter for liquid chromatography. In measuring the molecular weight of the toner sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Alternatively, the molecular weights manufactured by Toyo Soda Industry Co., Ltd. are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3. It is suitable to use 9 × 10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

  Whether the binder resin is insoluble in THF is determined at the time of preparing a THF sample solution for molecular weight distribution measurement. That is, when a 0.45 μm filter unit is attached to the tip of the syringe and the liquid is pushed out of the syringe, it is determined that there is no THF-insoluble matter unless the filter is clogged.

  Moreover, it is preferable that the binder resin used for this invention has the endothermic peak in DSC in the range of 60-70 degreeC. If the temperature is less than 60 ° C., the toner storage stability is affected, causing problems such as solidification of the toner in the cartridge or the hopper. On the other hand, when the temperature exceeds 70 ° C., the toner productivity is affected and problems such as a decrease in feed during pulverization occur. The endothermic peak in DSC is measured, for example, by Rigaku THRMOFLEX TG8110 manufactured by Rigaku Corporation under the condition of a heating rate of 10 ° C./min, and the main maximum peak of the endothermic curve is read.

  Moreover, it is preferable that the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the binder resin used for this invention is 2 <= Mw / Mn <= 10. When Mw / Mn exceeds 10, gloss cannot be obtained when the toner is fixed, and a high-quality image cannot be obtained. Further, if Mw / Mn is less than 2, productivity is reduced in the pulverization step at the time of toner production, and blades and sleeves are contaminated by long-term use, and filming is likely to occur.

The binder resin used in the present invention preferably has an acid value of 10 KOHmg / g or less in the interaction between the charge control agent and the additive described later.
It is known that the relationship between the chargeability of the polyester resin and the acid value is almost proportional, and that the higher the acid value, the greater the negative chargeability of the resin and, at the same time, affecting the environmental characteristics of charging. That is, when the acid value is high, the charge amount is high under low temperature and low humidity, and the charge amount is low under high temperature and high humidity. Due to changes in the amount of charge due to the environment, changes in background contamination, image density, and color reproducibility become large, making it difficult to maintain high image quality. In general, when the acid value exceeds 20 KOHmg / g, there is a risk that the charge amount will increase and the environmental fluctuation will deteriorate.

  In the polyester resin used in the present invention, the resistance as toner particles is controlled by the charge control agent, hydrophobic silica, hydrophobic titanium oxide, and the chargeability and resistance of the hydrophobic titanium oxide described later. For this reason, when the acid value of the polyester resin exceeds 10 KOH mg / g, the charge control effect of the charge control agent, hydrophobic silica, and hydrophobic titanium oxide is inhibited. The acid value of the polyester resin used in the present invention is preferably 10 KOH mg / g or less, more preferably 5 KOH mg / g or less.

Furthermore, the binder resin used in the present invention preferably has a temperature at which the apparent viscosity by a flow tester becomes 10 ³ Pa · s is 95 to 120 ° C. If it is less than 95 ° C., there is no margin for hot offset during fixing, while if it exceeds 120 ° C., sufficient gloss cannot be obtained. The temperature at which the apparent viscosity is 10 ³ Pa · s is measured by using, for example, a CFT-500 model manufactured by Shimadzu Corporation as a flow tester, a load of 10 kg / cm ² , an orifice diameter of 1 mm × length of 1 mm, and a heating rate of 5 ° C./min. The temperature at which the apparent viscosity becomes 10 ³ Pa · s is read.

Next, the charge control agent used for the toner of the present invention will be described.
The charge control agent used in the toner of the present invention is a metal salt compound of salicylic acid or a salicylic acid derivative, and can be represented by the following general formula.

（但しＲ^１、Ｒ^２およびＲ^３は水素又は炭素数１〜１０のアルキル基或いはアーリル基であるが、特に水素又は炭素数１〜６のアルキル基或いはアーリル基が望ましい。ここでＲ^１、Ｒ^２およびＲ^３は同時に同じであっても異なっていてもよい。また、Ｍｅは亜鉛、ニッケル、コバルト、鉛、クロムから選ばれるいずれかの金属であるが、特に亜鉛が望ましい。）

(However, R ¹ , R ² and R ³ are hydrogen, an alkyl group having 1 to 10 carbon atoms or an aryl group, and particularly preferably hydrogen, an alkyl group having 1 to 6 carbon atoms or an aryl group. Here, R ¹ , R ² and R ³ may be the same or different at the same time, and Me is any metal selected from zinc, nickel, cobalt, lead, and chromium, with zinc being particularly preferred.

  The metal salt compound represented by the above general formula is described in CLARK, J. et al. L. Kao, H .; (1948) J. Org. Amer. Chem. Soc. 70, 2151 can be easily synthesized. For example, 2 mol of salicylic acid sodium salt (including a sodium salt of a salicylic acid derivative) and 1 mol of zinc chloride are mixed in a solvent, mixed, heated and stirred to obtain a zinc salt. This metal salt compound is a white crystal and does not show coloration when dispersed in a toner binder. A metal salt other than a zinc salt can also be produced according to the above method.

These metal salt compounds may be used alone or in combination of two or more. Further, other charge control agents may be used in combination with the metal salt compound of salicylic acid or a salicylic acid derivative. Other charge control agents used in the present invention may be used in combination.
For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts, fluorine-modified quaternary ammonium salts, alkylamides, phosphorus Or a single compound. In particular, in a color toner, a transparent or white substance that does not impair the color tone is used in combination. For example, specifically, organic boron salts, fluorine-containing quaternary ammonium salts, calixarene compounds and the like are used, but are not limited thereto.

Dispersion of the charge control agent in the binder resin is one factor that determines the charging performance of the toner.
In the present invention, a combination of a specific binder resin and a specific charge control agent provides a toner having good chargeability and excellent charge rise. However, as described above, it is apparent that the dispersibility (compatibility) between the binder resin and the charge control agent affects the charging performance. The inventors of the present invention studied the dispersibility of the charge control agent and obtained the optimum range by paying attention to the molecular weight distribution of the binder resin, the apparent viscosity and the acid value by a flow tester.

According to the present invention, the binder resin has a main peak in the region of weight molecular weight of 3 × 10 ^{3 to} 9 × 10 ³ , and the apparent viscosity by the flow tester is 95 to 120 at a temperature at which the apparent viscosity is 10 ³ Pa · s. ° C, and the acid value is 10 KOHmg / g or less. When a charge control agent comprising a binder resin having this characteristic and a metal salt compound of salicylic acid or a salicylic acid derivative is melt-kneaded, the charge control agent is appropriately dispersed in the binder resin, the charge rising property is good, and changes with time Therefore, a stable toner can be obtained which is stable with a small amount and does not change greatly in the environment.

When the main peak of the weight molecular weight of the binder resin is in a region smaller than the region of 3 × 10 ^{3 to} 9 × 10 ^{3 or} the temperature at which the apparent viscosity by the flow tester is 10 ³ Pa · s is less than 95 ° C., the binder resin Becomes a low molecular weight type and the charge control agent becomes difficult to disperse, and a sufficient charge amount cannot be obtained. When the temperature at which the main viscosity is larger than the weight molecular weight region or the apparent viscosity by the flow tester is 10 ³ Pa · s is higher than 120 ° C., the charge control agent becomes too finely dispersed, The charge amount is rather low. When the acid value of the binder resin is greater than 10 KOH mg / g, the charge amount cannot be continuously increased with time in combination with the charge control agent and cannot be saturated, and charging stability with time cannot be obtained.

  The amount of the specific charge control agent used in the toner of the present invention is preferably 0.1 to 10% by weight, and preferably 0.5 to 5% by weight, based on the toner particles. If it is less than 0.1% by weight, the dispersion with the binder resin cannot be controlled, the rise of charge and the amount of charge are not sufficient, and it tends to affect images such as background stains and dust. When the amount exceeds 10% by weight, the dispersion in the binder resin is deteriorated, the charge amount distribution is widened, and scumming or toner scattering in the machine tends to occur.

The additives used in the toner of the present invention, hydrophobized silica primary particle diameter 0.01～0.03Myuemu, specific surface area in the primary particle diameter 0.01~0.03μm 60~140m ² / The titanium oxide which has the specific performance of the hydrophobization process of g is mentioned. By using these additives in combination with the polyester resin and the charge control agent, a toner having stable chargeability can be obtained.

  That is, by attaching silica having a primary particle diameter of 0.01 to 0.03 μm to the surface of the base toner, the required fluidity and chargeability are imparted to the toner, and the toner is exposed on the developing roller and from the developing roller. Developability to the body is improved. The addition amount of this type of silica is preferably 2.1 parts by weight or more with respect to 100 parts by weight of the base toner. This makes the thin layer of the toner uniform on the developing roller and greatly improves the unevenness of the thin layer. Further, the generation of white streaks due to the fusion of the toner to the stirring developer coating blade is prevented by further agitating the developing roller. If the amount is less than this, the toner fluidity may not be sufficiently obtained, and a necessary amount of toner may not be supplied to the developing roller, or a necessary toner charge amount may not be obtained. Further, a thin layer of toner on the developing roller becomes non-uniform, and there are cases where uniform development of the toner and an image cannot be obtained, or white streaks are generated due to fusion of the toner to the stirring developer coating blade.

Further, by adhering hydrophobically treated titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g to the surface of the base toner, the charging property of the toner is stabilized. Charge rise and charge up are prevented. The addition amount of this type of titanium oxide is preferably 0.4 to 1.0 part by weight based on 100 parts by weight of the base toner. If the amount is less than 0.4 parts by weight, the toner may be too charged and sufficient toner may not be developed. On the other hand, when added in an amount of more than 1.0 part by weight, the chargeability of the toner is too low, and the toner may scatter from the developing roller or cause background stains.
The base toner means particles in the middle of production containing materials other than additives, at least a binder resin, a colorant, and a charge control agent.

Among the additives used in the present invention, hydrophobic titanium oxide is obtained by surface-treating titanium oxide fine particles having a water-soluble component amount of 0.2% by weight or more produced by a wet method. In the absorption method, the transmittance at 300 nm is 35% or more, and the transmittance at 600 nm is 80% or more.
Titanium oxide is generally produced by a wet method. In general, gold ore, pyrite, plate titanium stone, ilmenite and the like are used as ores containing titanium. There is a sulfuric acid method in which concentrated sulfuric acid is added to these ores to dissolve them, or a chlorine method in which these ores are dehydrated with carbon materials and exposed to chlorine gas. In either case, titanium hydroxide Ti (OH) ₂ is purified, and crystals of TiO ₂ are precipitated by hydrolysis in the final stage. For this reason, there are some water-soluble components. These are alkali metal ions and acid components contained in ores and catalysts and processing agents used in the manufacturing process, such as PO ₄ ²⁻ , SO ₄ ²⁻ , Cl ⁻ , Na ⁺ , Mg ²⁺ , Li ^{+ and the} like. is there. These water-soluble components are known to affect the chargeability and resistance, and it is said that a high charge amount can be maintained by controlling to less than 0.2% by weight. However, in the present invention, not the higher chargeability of titanium oxide but its function was found in resistance and particle size distribution, and the present invention was achieved.

That is, in the present invention, the use of titanium oxide having a water-soluble component amount of 0.2% by weight or more can suppress the increase in the charge amount with time, and the effect can be obtained by using it together with silica. become. The amount of water-soluble component is determined according to JIS K5116-1973.
In general, surface treatment with a coupling agent or the like is performed to increase the functionality of titanium oxide. However, the amount of water-soluble components of titanium oxide affects the surface treatment and It also affects the resistance and charging characteristics. Furthermore, the secondary aggregation property of titanium oxide is changed depending on the degree of dispersion in the surface treatment. In general, a uniform treatment and a high dispersion treatment may be performed in order to maintain the primary particle diameter, but titanium oxide alone has many problems such as an increase in charging with time and adhesion to the photoreceptor. Therefore, although the degree of dispersion is increased in the present invention, the problem is solved by setting the resistance low. As an index indicating the particle size of titanium oxide, there is one based on transmittance in a specific solvent.

  In the present invention, it is desirable that the transmittance at 300 nm is 35% or more and the transmittance at 600 nm is 80% or more in the UV absorption method. Titanium oxide surface-treated with a large amount of water-soluble components in order to set the resistance low requires a transmittance of 35% or more at 300 nm. Since the resistance is low, the particle size is controlled to be small and easily dispersed on the toner surface. On the other hand, the transmittance at 600 nm needs to be 80% or more. If it is less than 80%, the surface treatment with a coupling agent or the like is not uniform, and aggregates are formed by the treatment.

The transmittance was measured as follows.
20 g of a reagent (polyoxyethylene octylphenyl ether) was precisely weighed, placed in a beaker, and added with ion exchange water so that the solid content concentration became 1 wt%. This aqueous solution was dispersed with an ultrasonic vibrator (HONDA W-113), and further stirred with a magnetic stirrer to prepare a measurement solvent. Next, 25 mg of a sample (titanium oxide) was placed in a 300 ml Erlenmeyer flask, 250 g of the measurement solvent was added thereto, and the mixture was stirred and dispersed with a magnetic stirrer for 5 minutes. Thereafter, the Erlenmeyer flask was subjected to an ultrasonic vibrator and dispersed for 5 minutes. Occasionally the flask was shaken by hand to help disperse the aggregates. Immediately after dispersion, 2 g of the dispersion was measured and placed in a 30 ml sample bottle, and 18 g of ion-exchanged water was added thereto. Gently shake and mix by hand so as not to disturb, take the resulting mixed solvent in a glass cell with a path width of 1 cm, set in a UV device (Shimadzu spectrophotometer system UV-3100), and in the range of 300-700 nm Measure the absorbance with.

  As the colorant used in the toner of the present invention, known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow oxidation Iron, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sae Red, paracro Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazo Red, Polyazo Red, Chrome Permillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indance Ren Blue (RS, BC), Indigo, Ultramarine Blue, Bituminous Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green , Phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The amount used is generally 0.1 to 50 parts by weight per 100 parts by weight of the binder resin.

  The toner of the present invention includes other additives such as Teflon (registered trademark), fluoropolymer, low molecular weight polyolefin, metal oxide (aluminum oxide, tin oxide, antimony oxide, etc.), conductivity imparting agent (carbon black, tin oxide, etc.) ), A magnetic material, and those obtained by surface-treating those additives may be used in combination. These additives may be used alone or in combination of two or more, and the content is generally 0.1 to 10 parts by weight with respect to 100 parts by weight of the toner.

  The toner of the present invention may be a magnetic toner containing a magnetic material. Magnetic materials include iron oxide (magnetite, ferrite, hematite, etc.), metals (iron, cobalt, nickel, etc.), metals and aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, calcium, Examples thereof include alloys or mixtures of cadmium, manganese, selenium, titanium, tungsten, vanadium, and the like. These magnetic materials preferably have a volume average particle size of about 0.1 to 2 μm, and the amount contained in the toner is 5 to 150 parts with respect to 100 parts by weight of the binder resin.

  The toner of the present invention may be used as a two-component developer using a carrier. The carrier used here may be any conventional system such as iron powder, ferrite, magnetite, and glass beads. These carriers may be resin-coated. The resin used in this case is a known one such as polyfluorinated carbon, polyvinyl chloride, polyvinylidene chloride, phenol resin, polyvinyl acetal, acrylic resin, silicon resin, etc., but the silicon coated carrier is excellent from the viewpoint of developer life. Yes. Moreover, you may contain electrically conductive powder etc. in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance. The mixing ratio of the toner and carrier of the two-component developer is generally 0.5 to 20.0 parts by weight of toner with respect to 100 parts by weight of carrier.

  The toner production method of the present invention includes a mechanically dry mixing step of a binder resin, a colorant, and a charge control agent among the main components, a heating and melting step, a rolling cooling and pulverizing step, a classification step, and an additive. And a step of mixing. In particular, in the step of mechanically dry-mixing or the step of heat-melting and kneading, a production method is also included in which powder (sub-product) other than the particles that are obtained in the pulverization step or classification step is returned and reused.

  The powders (sub-products) other than the particles used as the product referred to here are fine particles and coarse particles other than the components used as the product having a desired particle size obtained in the pulverizing step after the melt-kneading step, and subsequent classification. It means fine particles or coarse particles other than the components that are produced in the process and have a desired particle size. It is preferable that 0 to 30 parts by weight of the by-product is mixed with the raw material and preferably the main raw material 100 in the step of mixing or melt-kneading the by-product. The by-product to be mixed may be in the form of fine particles or solidified into a lump. When the amount of the by-product to be mixed exceeds 30 parts by weight, the thermal characteristics of the main raw material are impaired, and the fixability and storage stability as a toner are affected.

  The mixing step of mechanically mixing at least the binder resin, the colorant, and the toner component of the charge control agent, and the mixing step of mechanically mixing the toner component including the by-product with the binder resin, the colorant, and the charge control agent are rotated. What is necessary is just to carry out on normal conditions using the normal mixer etc. with the feather to make, and there is no restriction | limiting in particular.

  When the above mixing process is completed, the mixture is then charged into a kneader and melt-kneaded. As the melt kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Kay Sea Kay Co., Ltd., PCM type twin screw extruder manufactured by Ikegai Iron Works Co., Ltd. A kneader or the like is preferably used. It is important that this melt-kneading is performed under appropriate conditions so as not to cause breakage of the molecular chain of the binder resin. Specifically, the melt kneading temperature should be performed with reference to the softening point of the binder resin. If the temperature is lower than the softening point, the binder resin is severely cut. If the temperature is too high, the charge control and the dispersion of the coloring material do not proceed.

  When the above melt-kneading process is completed, the kneaded product is then pulverized. In this pulverization step, it is preferable to first coarsely pulverize and then finely pulverize. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a rotor and a stator that rotate mechanically is preferably used. . After the pulverization step is completed, the pulverized product is classified in an air stream by centrifugal force or the like, thereby producing a toner product having a predetermined particle size, for example, an average particle size of 5 to 20 μm.

  In order to produce the toner of the present invention, the hydrophobic silica fine powder listed above for the base toner produced as described above in order to improve fluidity, storage stability, developability and transferability as a developer. Add and mix inorganic fine particles. For mixing external additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the external additive, the external additive may be added in the middle or gradually. Of course, you may change the rotation speed of a mixer, rolling speed, time, temperature, etc. A strong load may be given first, then a relatively weak load, and vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, and the like.

  The toner of the present invention can achieve the object of the present invention by the four elements such as the binder resin, the charge control agent, the additive, and the by-product as described above, and by optimizing and balancing their unique characteristic values. It is.

As an image forming method and an image forming apparatus performed using the dry one-component developer or the dry two-component developer according to the present invention, a conventionally known electrophotographic method and apparatus can be used.
Basically, a latent image forming step of forming a latent image on the latent image holding member, a step of developing the latent image using a developer on the developer carrying member, and transferring the developed toner image onto the transfer member An image forming method and an image forming apparatus that undergo a transfer step and a fixing step of heating and fixing a toner image on a transfer body.

In the step of developing the latent image on the latent image holding member of the image forming method of the present invention, an alternating electric field may be applied.
In the developing device (20) of the present embodiment shown in FIG. 1, during development, a vibration bias voltage in which an AC voltage is superimposed on a DC voltage is applied to the developing sleeve (21) as a developing bias by a power source (22). The The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing section (23). In this alternating electric field, the developer toner and the carrier vibrate vigorously, and the toner flies off the electrostatic binding force to the developing sleeve (21) and the carrier and flies to the photosensitive drum (24). It adheres corresponding to the image.
The difference (maximum peak voltage) between the maximum value and the minimum value of the vibration bias voltage is preferably 0.5 to 5 KV, and the frequency is preferably 1 to 10 KHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave, or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. This is preferable for preventing toner adhesion.
When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution faithfully and improve roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

In the image forming apparatus of the present invention, a process cartridge that integrally supports at least one unit selected from a photosensitive member and a charging unit, a developing unit, and a cleaning unit and is detachable from the main body of the image forming apparatus may be used. .
FIG. 2 shows a schematic configuration of an image forming apparatus having the process cartridge of the present invention.
In the figure, (10) shows the entire process cartridge, (11) shows a photoconductor, (12) shows charging means, (13) shows developing means, and (14) shows cleaning means.
In the present invention, a plurality of components such as the above-described photoreceptor (11), charging means (12), developing means (13), and cleaning means (14) are integrally combined as a process cartridge. The process cartridge is configured to be detachable from an image forming apparatus main body such as a copying machine or a printer.

  In the image forming apparatus having the process cartridge of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging unit, and then receives image exposure light from an image exposing unit such as slit exposure or laser beam scanning exposure. An electrostatic latent image is sequentially formed on the peripheral surface of the body, and the formed electrostatic latent image is then developed with toner by a developing unit, and the developed toner image is transferred between the photosensitive member and the transfer unit from the paper feeding unit. Then, the image is sequentially transferred to the transfer material fed in synchronization with the rotation of the photosensitive member by the transfer means. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor after the image transfer is cleaned by removing toner remaining after transfer by a cleaning unit, and after being further neutralized, it is repeatedly used for image formation.

In the fixing step of the image forming method of the present invention, the fixing device includes a heating body including a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film. It is also possible to use a fixing device that has a recording material on which an unfixed image is formed between the film and the pressure member and heat-fixes the recording material.
The fixing device of the present invention may be a so-called surf fixing device that rotates and fixes a fixing film as shown in FIG. In detail, the fixing film is an endless belt-like heat-resistant film, and is fixed and supported by a driving roller, a driven roller, and a heater support provided below the rollers, which are support rotating members of the film. It is stretched around the heating element.
The driven roller also serves as a tension roller for the fixing film, and the fixing film is rotated in the clockwise direction by the rotational driving of the driving roller in the clockwise direction in the drawing. The rotational driving speed is adjusted to a speed at which the transfer material and the fixing film have the same speed in the fixing nip region L where the pressure roller and the fixing film are in contact with each other.
Here, the pressure roller is a roller having a rubber elastic layer having good releasability such as silicon rubber, and a contact pressure of a total pressure of 4 to 10 kg against the fixing nip region L while rotating counterclockwise. With pressure contact.
The fixing film preferably has excellent heat resistance, releasability and durability, and a thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used. For example, at least an image of a single layer film of a heat-resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin), or a composite layer film, for example, a 20 μm thick film The contact surface is coated with a release coating layer of PTFE (tetrafluoroethylene resin), PFA or other fluororesin added with a conductive material to a thickness of 10 μm, or an elastic layer such as fluororubber or silicon rubber. It is a thing.

In FIG. 3, the heating body of the present embodiment is composed of a flat substrate and a fixing heater, and the flat substrate is made of a material having high thermal conductivity and high electrical resistivity such as alumina and is in contact with the fixing film. A fixing heater composed of a resistance heating element is provided on the surface in the longitudinal direction. Such a fixing heater is formed by coating an electric resistance material such as Ag / Pd or Ta ₂ N in a linear or belt shape by screen printing or the like. In addition, electrodes (not shown) are formed at both ends of the fixing heater, and the resistance heating element generates heat when energized between the electrodes. Furthermore, a fixing temperature sensor constituted by a thermistor is provided on the surface of the substrate opposite to the surface provided with the fixing heater.
The temperature information of the substrate detected by the fixing temperature sensor is sent to a control means (not shown), and the amount of electric power supplied to the fixing heater is controlled by the control means, and the heating body is controlled to a predetermined temperature.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to only these examples. In the following examples, “part” and “%” are based on weight unless otherwise specified.
(Binder resin synthesis example)
Synthesis example 1
In a four-necked separable flask with a stirrer, thermometer, nitrogen inlet, flow-down condenser, and condenser, 740 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxy Esterification catalyst of 300 g of ethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 466 g of dimethyl terephthalate, 80 g of isododecenyl succinic anhydride, and 114 g of tri-n-butyl 1,2,4-benzenetricarboxylate Added with. Under a nitrogen atmosphere, the temperature was raised to 210 ° C. in the first half, and the reaction was carried out with stirring at 210 ° C. under reduced pressure in the second half. As a result, the molecular weight is 5 × 10 ² or less, the content is 3.5%, the molecular weight main peak is 7.5 × 10 ³ , the Tg is 62 ° C., the Mw / Mn ratio is 5.1, the acid value is 2.3 KOHmg / g, and the apparent viscosity is measured by a flow tester. A polyester resin (hereinafter, polyester resin A) having a temperature of 112 ° C. at which 10 ³ Pa · s was reached was obtained. The obtained polyester resin did not contain THF-insoluble matter.

Synthesis example 2
71,225 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 165 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 500 g of terephthalic acid, 130 g of isododecenyl succinic anhydride and 170 g of triisopropyl 1,2,4-benzenetricarboxylate were added to the flask along with the esterification catalyst. These were reacted in the same apparatus and the same formulation as in Synthesis Example 1, and the content of molecular weight 5 × 10 ² or less was 3.0%, the molecular weight main peak 8 × 10 ³ , Tg 62 ° C., Mw / Mn ratio 4.7. A polyester resin (hereinafter, polyester resin B) having an acid value of 0.5 KOH mg / g and a temperature of 116 ° C. at which the apparent viscosity by a flow tester becomes 10 ³ Pa · s was obtained.

Synthesis example 3
650 g of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 650 g of polyoxyethylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 515 g of isophthalic acid, 70 g of isooctenyl succinic acid and 80 g of 1,2,4-benzenetricarboxylic acid were added to the flask together with the esterification catalyst. These were reacted in the same apparatus and the same formulation as in Synthesis Example 1, the content of molecular weight 5 × 10 ² or less 2.1%, molecular weight main peak 8.2 × 10 ³ , Tg 61 ° C., Mw / Mn ratio 4 A polyester resin (hereinafter, polyester resin C) having an acid value of 10.0 KOH mg / g and an apparent viscosity of 10 ³ Pa · s by a flow tester of 117 ° C. was obtained.

(Examples of additives)
(I) Hydrophobized silica having a primary particle size of 0.01 to 0.03 μm

(II) Hydrophobized titanium oxide having a primary particle size of 0.01 to 0.03 μm and a specific surface area of 60 to 140 m ² / g

Synthesis example 1
300 g of titanium oxide (MT-150A manufactured by Teika Co., Ltd.) having a primary average particle size of 0.015 μm containing 0.35% of a water-soluble component made by a wet method is added to a toluene solution in which 35 g of isobutylmethoxysilane is dissolved. Added and dispersed with stirring. Thereafter, the solvent was dried up and pulverized with a jet mill to obtain a coupling agent-treated titanium oxide (titanium oxide II-1).

Synthesis example 2
300 g of titanium oxide (MT-150A manufactured by Teika Co., Ltd.) having a primary average particle size of 0.015 μm containing 0.35% of a water-soluble component made by a wet method is added to a toluene solution in which 25 g of isobutylmethoxysilane is dissolved. Added and dispersed with stirring. Thereafter, the solvent was dried up and pulverized with a jet mill to obtain a coupling agent-treated titanium oxide (titanium oxide II-2).

Synthesis example 3
A toluene solution in which 300 g of titanium oxide (MT-150A manufactured by Teika Co., Ltd.) having a primary average particle size of 0.015 μm and containing 0.35% of a water-soluble component made by a wet method is dissolved in 30 g of methyltrimethoxysilane. Added to and dispersed. Thereafter, the solvent was dried up and jet milled to obtain a coupling agent-treated titanium oxide (titanium oxide II-3).

Synthesis example 4
300 g of titanium oxide (MT-150A manufactured by Taika Co., Ltd.) having a primary average particle size of 0.015 μm and containing 0.35% of a water-soluble component produced by a wet method was dissolved in 30 g of n-butyltrimethoxysilane. Added to the toluene solution and dispersed. Thereafter, the solvent was dried up and pulverized with a jet mill to obtain a coupling agent-treated titanium oxide (titanium oxide II-4).
The characteristic values of the obtained titanium oxide are as shown in the table below.

Example 1
The colorant was processed according to the following formulation.
Yellow colorant formulation:
Polyester resin A 100 parts by weight C.I. I. Pigment Yellow 180 100 parts by weight Red colorant formulation:
Polyester resin A 100 parts by weight C.I. I. Pigment Red 122 100 parts by weight Blue colorant formulation:
Polyester resin A 100 parts by weight C.I. I. Pigment Blue 15.3 100 parts by weight black colorant formulation:
100 parts by weight of polyester resin A 100 parts by weight of carbon black The above materials were mixed for each color in a Henschel mixer, and then the mixture was put into an air-cooled two-roll mill and melt-kneaded for 15 minutes after the addition. Thereafter, the kneaded product was rolled and cooled, and coarsely pulverized with a hammer mill to obtain a polyester resin-treated coloring material.
Next, a toner was prepared according to the following formulation.
Yellow toner formulation;
Polyester resin A 94 parts by weight Polyester resin A-treated yellow colorant 12 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Magenta toner
Polyester resin A 95 parts by weight Polyester resin A treated red colorant 10 parts by weight 3,5-ditertiarybutyl salicylate compound 3 parts by weight Cyan toner formulation:
Polyester resin A 97 parts by weight Polyester resin A treated blue colorant 6 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Black toner formulation:
Polyester resin A 93 parts by weight Polyester resin A treated black colorant 12 parts by weight Polyester resin A treated blue colorant 2 parts by weight 3,5-ditertiary butylsalicylic acid zinc compound 3 parts by weight The above materials for each color in a Henschel mixer The resulting mixture was put into a roll mill heated to 110 ° C., and melted and kneaded for 20 minutes after the addition. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet mill. Further, fine powder was removed by an air classifier to obtain each color toner. The fine powder obtained in the pulverization step and the classification step was stored as a by-product 1 for each color.

Using the by-product 1 obtained in the toner manufacturing process, a toner was manufactured according to the following formulation.
Yellow toner prescription:
Polyester resin A 94 parts by weight Polyester resin A treated yellow colorant 12 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Yellow by-product 1 20 parts by weight Magenta toner formulation:
Polyester resin A 95 parts by weight Polyester resin A treated red colorant 10 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Magenta by-product 1 20 parts by weight Cyan toner formulation:
Polyester resin A 97 parts by weight Polyester resin A treated blue colorant 6 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Cyan by-product 1 20 parts by weight Black toner formulation:
Polyester resin A 93 parts by weight Polyester resin A treated black colorant 12 parts by weight Polyester resin A treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Black by-product 1 20 parts by weight For each color The above materials were mixed in a Henschel mixer, and the resulting mixture was put into a roll mill heated to 110 ° C., and melted and kneaded for 20 minutes. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an air jet mill. Further, fine powder was removed by an air classifier to obtain each color toner. The following additives were mixed in a Henschel mixer with respect to 100 parts by weight of the obtained color toners to form a one-component developer.
I-2 Hydrophobic silica 2.5 parts by weight
II-1 Hydrophobic titanium oxide 0.8 part by weight The obtained one-component developer was set in a commercially available digital full-color printer (IPSiO Color 6500 manufactured by Ricoh Company) to form an image. The obtained image was clear and no abnormalities such as background stains were observed. When the developing roller was visually observed, the toner thin layer on the roller was uniform. The amount of charge on the developing roller was measured by a suction method. As a result, yellow developer was −30 μC / g, magenta developer was −26 μC / g, cyan developer was −29 μC / g, and black developer was −27 μC / g. there were. Images were similarly formed under high temperature and high humidity conditions of 27 ° C. and 80% RH, and low temperature and low humidity conditions of 10 ° C. and 15% RH, but no change was observed, and a good image was formed. When a durability test was performed on a full color image up to a total of 20,000 sheets in each environment continuously at room temperature, low temperature and low humidity, high temperature and high humidity, and normal temperature, no significant change was seen in the fixed image. The image was clear with no background stains. When the developing roller was visually observed, there was no significant change in the toner thin layer on the roller. At this time, the developer charge amount was yellow developer-28 μC / g, magenta developer-25 μC / g, cyan development. Agent-27 μC / g and black developer-26 μC / g were stable. The developing roller, doctor roller, and photoreceptor were visually observed, but no filming was observed. Further, a durability test was performed up to 50,000 sheets. Filming was not seen on the developing roller and doctor roller, the charge amount was stable, and no abnormal image was seen.

Example 2
The colorant was processed according to the following formulation.
Yellow colorant formulation:
Polyester resin C 100 parts by weight C.I. I. Pigment Yellow 180 100 parts by weight Red colorant formulation:
Polyester resin C 100 parts by weight C.I. I. Pigment Red 146 100 parts by weight blue colorant formulation:
Polyester resin C 100 parts by weight C.I. I. Pigment Blue 15.3 100 parts by weight black colorant formulation:
100 parts by weight of polyester resin C 100 parts by weight of carbon black The above materials were mixed for each color in a Henschel mixer, and then the mixture was put into an air-cooled two-roll mill and melt-kneaded for 15 minutes. Thereafter, the kneaded product was rolled and cooled, and coarsely pulverized with a hammer mill to obtain a polyester resin-treated coloring material.
Next, a toner was prepared according to the following formulation.
Yellow toner formulation;
Polyester resin C 94 parts by weight Polyester resin C-treated yellow colorant 12 parts by weight 3,5-ditertiarybutylsalicylate zinc compound 3 parts by weight Magenta toner
Polyester resin C 95 parts by weight Polyester resin C-treated red colorant 10 parts by weight 3,5-ditertiarybutyl salicylate compound 3 parts by weight Cyan toner formulation:
Polyester resin C 97 parts by weight Polyester resin C-treated blue colorant 6 parts by weight 3,5-ditertiarybutyl salicylate compound 3 parts by weight Black toner formulation:
Polyester resin C 93 parts by weight Polyester resin C resin-treated black colorant 12 parts by weight Polyester resin C resin-treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight The mixture was put into a mixer and mixed, and the resulting mixture was put into a biaxial continuous kneader heated to 80 ° C. and melt-kneaded. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an airflow pulverizer. Further, fine powder was removed by an air classifier to obtain each color toner.
Using the by-product 2 obtained in the pulverization step and the classification step, a toner was manufactured according to the following formulation.
Yellow toner prescription:
Polyester resin C 94 parts by weight Polyester resin C-treated yellow colorant 12 parts by weight 3,5-ditertiarybutyl salicylate zinc compound 3 parts by weight Yellow by-product 2 15 parts by weight Magenta toner formulation:
Polyester resin C 95 parts by weight Polyester resin C-treated red colorant 10 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Magenta by-product 2 15 parts by weight Cyan toner formulation:
Polyester resin C 97 parts by weight Polyester resin C treated blue colorant 6 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Cyan by-product 2 15 parts by weight Black toner formulation:
Polyester resin C 93 parts by weight Polyester resin C resin-treated black colorant 12 parts by weight Polyester resin C resin-treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Black sub-product 2 15 parts by weight The above materials were mixed in a Henschel mixer for each color, and the resulting mixture was put into a biaxial continuous kneader heated to 80 ° C. and melt-kneaded. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an airflow pulverizer. Further, fine powder was removed by an air classifier to obtain each color toner.
The following additives were mixed with 100 parts by weight of each color toner using a Henschel mixer.
I-3 Hydrophobic silica 2.1 parts by weight
II-4 Hydrophobic titanium oxide 1.0 part by weight The obtained toner 7 parts by weight and silicon resin coated ferrite carrier 93 parts were mixed to prepare a two-component developer. The obtained two-component developer was set in a commercially available digital full-color printer (IPSiO Color 7100 manufactured by Ricoh) to form an image. The obtained image was clear with no background stains. No abnormalities were observed in image and charging at high temperature and high humidity and low temperature and low humidity. Even when a durability test of up to 20,000 sheets with a full-color image was performed, no abnormal image was observed, and the inside of the apparatus was observed after the test, but no scattering was observed, and there was no adhesion to the photoreceptor. Further, a durability test of up to 50,000 sheets was performed, but no filming on the developing roller and doctor roller was observed, the charge amount was stable, and no abnormal image was observed.

Example 3
The colorant was processed according to the following formulation.
Yellow colorant formulation:
Polyester resin B 100 parts by weight C.I. I. Pigment Yellow 180 100 parts by weight Red colorant formulation:
Polyester resin B 100 parts by weight C.I. I. Pigment Red 57.1 100 parts by weight Blue colorant formulation:
Polyester resin B 100 parts by weight C.I. I. Pigment Blue 15.3 100 parts by weight The above materials for each color were placed in a Henschel mixer and mixed, and then the mixture was placed in an air-cooled two-roll mill and melt-kneaded for 15 minutes. Thereafter, the kneaded product was rolled and cooled, and coarsely pulverized with a hammer mill to obtain a polyester resin-treated coloring material.
Next, a toner was prepared according to the following formulation.
Yellow toner prescription:
Polyester resin B 93 parts by weight Polyester resin B treated yellow colorant 14 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 2 parts by weight Magenta toner formulation:
Polyester resin B 94 parts by weight Polyester resin B treated red colorant 12 parts by weight 3,5-ditertiarybutyl salicylate zinc compound 2 parts by weight Cyan toner formulation:
Polyester resin B 96 parts by weight Polyester resin B treated blue colorant 8 parts by weight 3,5-ditertiarybutyl salicylate compound 3 parts by weight Black toner formulation:
Polyester resin B 99 parts by weight Carbon black 6 parts by weight Polyester resin B resin-treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight The above materials are mixed in a Henschel mixer for each color, and obtained. The obtained mixture was put into a biaxial continuous kneader heated to 80 ° C. and melt-kneaded. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an airflow pulverizer. Further, fine powder was removed by an air classifier to obtain each color toner. The by-product 4 obtained in the pulverization step and the classification step was passed through an air-cooled two-roll mill to form a lump.
Next, a toner was produced according to the following formulation.
Yellow toner prescription:
Polyester resin B 93 parts by weight Polyester resin B treated yellow colorant 14 parts by weight 3,5-ditertiarybutyl salicylate zinc compound 2 parts by weight Yellow by-product 4 30 parts by weight Magenta toner formulation:
Polyester resin B 94 parts by weight Polyester resin B treated red colorant 12 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 2 parts by weight Magenta byproduct 4 30 parts by weight Cyan toner formulation:
Polyester resin B 96 parts by weight Polyester resin B treated blue colorant 8 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Cyan by-product 4 30 parts by weight Black toner formulation:
Polyester resin B 99 parts by weight Carbon black 6 parts by weight Polyester resin B resin-treated blue colorant 2 parts by weight 3,5-ditertiary butylsalicylic acid zinc compound 3 parts Black by-product 4 30 parts by weight The obtained toner of each color 100 parts by weight The following additives were mixed with a Henschel mixer to obtain a one-component developer.
I-2 Hydrophobic silica 2.5 parts by weight
II-2 Hydrophobic titanium oxide 0.8 parts by weight The obtained one-component developer was set on a commercially available digital full-color PPC (Imagio Neo C320 manufactured by Ricoh) to form an image. The obtained image was clear with no background stains. No abnormalities were observed in image and charging at high temperature and high humidity and low temperature and low humidity. Even when a durability test of up to 20,000 sheets with a full-color image was performed, no abnormal image was observed, and the inside of the apparatus was observed after the test, but no scattering was observed, and there was no adhesion to the photoreceptor. Further, a durability test of up to 50,000 sheets was performed, but no filming on the developing roller and doctor roller was observed, the charge amount was stable, and no abnormal image was observed.

Comparative Example 1
(Titanium oxide treatment)
Titanium oxide (MT-150A manufactured by Teika Co., Ltd.) containing 0.35% of a water-soluble component produced by a wet method was washed with water to obtain titanium oxide having a water-soluble component of 0.15%. 300 g of this titanium oxide was added and dispersed in a toluene solution in which 35 g of isobutyltrimethoxysilane was dissolved. Thereafter, the solvent was dried up, finely pulverized by a jet mill, and further highly dispersed by a pin mill to obtain a coupling agent-treated titanium oxide (hydrophobic titanium oxide II-5). When the absorbance of the obtained surface-treated titanium oxide was measured, the transmittance at 300 nm was 21%, and the transmittance at 600 nm was 97%.
Next, the following additives were mixed with 100 parts by weight of each color toner obtained in Example 1 to obtain a one-component developer.
I-2 Hydrophobic silica 2.4 parts by weight
II-5 Hydrophobic titanium oxide 0.6 part by weight The obtained one-component developer was set in a commercially available digital full-color printer (IPSiO Color 6500 manufactured by Ricoh Co., Ltd.) to form an image. The obtained image was slightly low in image density, but no scum was observed. When the developing roller was visually observed, the toner thin layer on the roller was uniform, but the development amount was low overall. The amount of charge on the developing roller was measured by a suction method. As a result, the yellow developer was −48 μC / g, the magenta developer was −40 μC / g, the cyan developer was −42 μC / g, and the black developer was −44 μC / g. there were. When an image was formed under high-temperature and high-humidity conditions of 27 ° C. and 80% RH, the image was blurred. Further, when an image was similarly formed under a low temperature and low humidity condition of 10 ° C. and 15% RH, a faint image having a lower image density was obtained. When a durability test was performed with full-color images under normal temperature, low temperature and low humidity, high temperature and high humidity, and normal temperature, abnormalities such as background stains, dust, and streaks occurred on the images. When the developing roller was visually observed at this time, streaks were generated in the circumferential direction in the toner thin layer on the roller. When the charge amount of the developer was measured, it was deteriorated to be yellow developer-23 μC / g, magenta developer-20 μC / g, cyan developer-20 μC / g, and black developer-19 μC / g.

Comparative Example 2
(Binder resin synthesis example 4)
The composition and the materials of Binder Resin Synthesis Example 1 were synthesized by changing the amount charged, the content 2.5% of molecular weight 5 × 10 ² or less, the molecular weight main peak 2.5 × 10 ⁴ , Tg 69 ° C., Mw / Mn A polyester resin (hereinafter, polyester resin D) having a ratio of 12.5, an acid value of 13.2 KOH mg / g, and an apparent viscosity of 10 ³ Pa · s temperature of 128 ° C. by a flow tester was obtained.
In the same manner as in Example 1, the colorant was processed according to the following formulation.
Yellow colorant formulation:
Polyester resin D 100 parts by weight C.I. I. Pigment Yellow 180 100 parts by weight Red colorant formulation:
Polyester resin D 100 parts by weight C.I. I. Pigment Red 146 100 parts by weight blue colorant formulation:
Polyester resin D 100 parts by weight C.I. I. Pigment Blue 15.3 100 parts by weight black colorant formulation:
100 parts by weight of polyester resin D 100 parts by weight of carbon black The above materials were mixed for each color in a Henschel mixer, and the mixture was placed in an air-cooled two-roll mill and melt-kneaded for 15 minutes. Thereafter, the kneaded product was rolled and cooled, and coarsely pulverized with a hammer mill to obtain a polyester resin C-treated coloring material.
Next, a toner was prepared according to the following formulation.
Yellow toner prescription:
Polyester resin D 94 parts by weight Polyester resin D treated yellow colorant 12 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight Magenta toner
Polyester resin D 95 parts by weight Polyester resin D-treated red colorant 10 parts by weight 3,5-ditertiarybutyl salicylate compound 3 parts by weight Cyan toner formulation:
Polyester resin D 97 parts by weight Polyester resin D-treated blue colorant 6 parts by weight 3,5-ditertiarybutylsalicylate zinc compound 3 parts by weight Black toner formulation:
Polyester resin D 93 parts by weight Polyester resin D resin-treated black colorant 12 parts by weight Polyester resin D resin-treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight The mixture was put into a mixer and mixed, and the resulting mixture was put into a biaxial continuous kneader heated to 90 ° C. and melt-kneaded. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an airflow pulverizer. Further, fine powder was removed by an air classifier to obtain each color toner. The following additives were mixed with 100 parts by weight of each color toner using a Henschel mixer.
I-2 Hydrophobic silica 2.5 parts by weight
II-1 Hydrophobic titanium oxide 0.8 parts by weight The obtained one-component developer was set in a commercially available digital full-color printer (IPSiO Color 6500 manufactured by Ricoh) in the same manner as in Example 1 to form an image. A dull image with no gloss was obtained. When the developing roller was visually observed, the toner thin layer on the roller was uniform. The amount of charge on the developing roller was measured by a suction method. As a result, the yellow developer was −23 μC / g, the magenta developer was −20 μC / g, the cyan developer was −21 μC / g, and the black developer was −19 μC / g. there were. When image formation was performed under high-temperature and high-humidity conditions of 27 ° C. and 80% RH, the background stains became severe. When a durability test was performed for a total of 20,000 sheets in full-color images under normal temperature, low temperature and low humidity, high temperature and high humidity, and normal temperature in each environment, the background stains deteriorated with about 10,000 images, and the image with noticeable dust became. When the developing roller was visually observed, the toner layer on the roller was uneven and a large number of streaks were generated in the circumferential direction.

Comparative Example 3
(Binder resin synthesis example 5)
The composition and the materials of Binder Resin Synthesis Example 1 were synthesized by changing the charged amount, the content of molecular weight 5 × 10 ² or less was 5.5%, the molecular weight main peak 3 × 10 ⁴ , Tg 69 ° C., Mw / Mn ratio 14 A polyester resin (hereinafter, polyester resin E) containing an acid value of 21 KOH mg / g, an apparent viscosity by a flow tester of 10 ³ Pa · s, a temperature of 135 ° C., and a THF insoluble content of 6% was obtained.
(Titanium oxide treatment)
Titanium oxide (MT-600B manufactured by Teika Co., Ltd.) containing 0.4% of a water-soluble component produced by a wet method was washed with water to obtain titanium oxide having a water-soluble component of 0.2%. This titanium oxide was subjected to a surface treatment in the same manner as in Comparative Example 1 to obtain a coupling agent-treated titanium oxide (hydrophobic titanium oxide II-6). The obtained surface-treated titanium oxide had a primary particle size of 0.060 μm, a specific surface area of 35 mg / cm ² , a transmittance of 300 nm at 16%, and a transmittance at 600 nm of 75%.
The colorant was treated in the same manner as in Example 3.
Yellow colorant formulation:
Polyester resin E 100 parts by weight C.I. I. Pigment Yellow 180 100 parts by weight Red colorant formulation:
Polyester resin E 100 parts by weight C.I. I. Pigment Red 57.1 100 parts by weight Blue colorant formulation:
Polyester resin E 100 parts by weight C.I. I. Pigment Blue 15.3 100 parts by weight The above materials for each color were placed in a Henschel mixer and mixed, and then the mixture was placed in an air-cooled two-roll mill and melt-kneaded for 15 minutes. Thereafter, the kneaded product was rolled and cooled, and coarsely pulverized with a hammer mill to obtain a polyester resin-treated coloring material.
Next, a toner was prepared according to the following formulation.
Yellow toner prescription:
Polyester resin E 93 parts by weight Polyester resin E treated yellow colorant 14 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 2 parts by weight Magenta toner
Polyester resin E 94 parts by weight Polyester resin E-treated red colorant 12 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 2 parts by weight Cyan toner formulation:
Polyester resin E 96 parts by weight Polyester resin E-treated blue colorant 8 parts by weight 3,5-ditertiarybutylsalicylate zinc compound 3 parts by weight Black toner formulation:
Polyester resin E 99 parts by weight Carbon black 6 parts by weight Polyester resin E resin-treated blue colorant 2 parts by weight 3,5-ditertiarybutylsalicylic acid zinc compound 3 parts by weight The above materials are mixed in a Henschel mixer for each color, and obtained. The obtained mixture was put into a biaxial continuous kneader heated to 80 ° C. and melt-kneaded. Thereafter, the kneaded product was cooled, coarsely pulverized with a hammer mill, and finely pulverized with an airflow pulverizer. Further, fine powder was removed by an air classifier to obtain each color toner. The following additives were mixed with a Henschel mixer to 100 parts by weight of the obtained color toners to obtain a one-component developer.
I-2 Hydrophobic silica 2.5 parts by weight
II-6 Hydrophobic Titanium Oxide 0.8 parts by weight The obtained one-component developer was set on a commercially available digital full-color PPC (Imagio Neo C320 manufactured by Ricoh) to form an image. The obtained initial image was slightly smudged and the image was not glossy and lacked clarity.
When an image was formed at high temperature and high humidity, the background stains deteriorated.
When a durability test of up to 20,000 sheets with a full-color image was performed, the background stain deteriorated from about 4,000 sheets, the image density began to decrease from the 8,000th sheet, and image blurring also occurred. . When the inside of the apparatus was visually confirmed at this time, toner scattering was conspicuous, and the toner layer on the developing roller was not uniform and there was a portion where a thin layer was not formed. Further, when the developing roller was observed, filming occurred on the surface.

FIG. 2 is a diagram showing a developing device of the present invention. 1 is a diagram showing a schematic configuration of an image forming apparatus having a process cartridge of the present invention. 1 is a diagram illustrating a fixing device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Process cartridge 11 Photoconductor 12 Charging means 13 Developing means 14 Cleaning means 20 Developing device 21 Developing sleeve 22 Power supply 23 Developing part 24 Photosensitive drum

Claims (16)

In a dry electrophotographic toner comprising at least a binder resin, a colorant, a charge control agent, and other additives as a main component, the binder resin is composed of one or more types of polyester resin, and the polyester resin contains a THF-insoluble component. In addition, the content ratio of the component having a molecular weight of 5 × 10 ² or less in the molecular weight distribution by gel permeation chromatography is 4% by weight or less, and has a main peak in the region of the weight molecular weight of 3 × 10 ^{3 to} 9 × 10 ^3. The charge control agent is made of a metal salt compound of salicylic acid or a salicylic acid derivative, and the additive is hydrophobized silica having a primary particle size of 0.01 to 0.03 μm and a primary particle size of 0.01 to 0.03 μm and hydrophobized titanium oxide having a specific surface area of 60 to 140 m ² / g, and the titanium oxide is manufactured by a wet method. The titanium oxide fine particles having a water-soluble component content of 0.2% by weight or more are surface-treated, and the transmittance at 300 nm is 35% or more and the transmittance at 600 nm is 80% or more in the UV absorption method. In the dry electrophotographic toner, a binder resin, a colorant and a charge control agent among the main components are mechanically dry mixed, heated and melted, rolled and cooled and pulverized, classified, and additives. A dry electrophotographic toner, wherein a by-product obtained from a pulverization step or a classification step of a production method comprising a mixing step is reused in a melt-kneading step. 2. The dry electrophotographic toner according to claim 1, wherein an endothermic peak in DSC of the binder resin is in a range of 60 to 70 ° C. 3. The dry electrophotography according to claim 1, wherein a ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the binder resin is 2 ≦ Mw / Mn ≦ 10. Toner. The dry electrophotographic toner according to claim 1, wherein the binder resin has an acid value of 10 KOH mg / g or less. The dry electrophotographic toner according to any one of claims 1 to 4, wherein a temperature at which an apparent viscosity of the binder resin by a flow tester is 10 ³ Pa · s is 95 to 120 ° C. 6. The dry electrophotographic toner according to claim 1, wherein the charge control agent is contained in an amount of 0.1 to 10% by weight based on toner particles. The additive has a hydrophobized silica having a primary particle diameter of 0.01 to 0.03 μm and a primary particle diameter of 0.01 to 0.03 μm with respect to 100 parts by weight of the base toner. 7. The dry electrophotographic toner according to claim 1, comprising 0.4 to 1.0 part by weight of hydrophobized titanium oxide having a specific surface area of 60 to 140 m ² / g. A dry one-component developer comprising the dry electrophotographic toner according to claim 1. A dry two-component developer comprising the dry electrophotographic toner according to claim 1 and a carrier. A latent image forming step for forming a latent image on the latent image holding member, a developing step for developing the latent image using a developer on the developer carrying member, and a transferring step for transferring the developed toner image onto the transfer member. An image forming method comprising a fixing step of heat-fixing a toner image on a transfer body, wherein the developing step uses the dry one-component developer according to claim 8 as a developer. Forming method. A latent image forming step for forming a latent image on the latent image holding member, a developing step for developing the latent image using a developer on the developer carrying member, and a transferring step for transferring the developed toner image onto the transfer member. An image forming method comprising a fixing step of heat-fixing a toner image on a transfer body, wherein the developing step uses the dry two-component developer according to claim 9 as a developer. Forming method. A container for holding the one-component developer according to claim 8, a container for replenishing the developer, a latent image forming means for forming the latent image, a developing means for developing the latent image with a developer, An image forming apparatus, comprising: a transfer unit for transferring the developed toner image onto a transfer member onto a transfer member; and a transfer unit for transferring the transfer image. A container for holding the dry two-component developer according to claim 9, a container for replenishing the toner, a latent image forming means for forming the latent image, a developing means for developing the latent image with a developer, An image forming apparatus, comprising: a transfer unit for transferring the developed toner image onto a transfer member onto a transfer member; and a transfer unit for transferring the transfer image. 14. The image forming apparatus according to claim 12, wherein the developing unit that develops the latent image on the latent image holding member includes an alternating electric field applying unit that applies an alternating electric field. In a process cartridge that integrally supports at least one member selected from a photosensitive member, a charging unit, a developing unit, and a cleaning unit and is detachable from the main body of the image forming apparatus, the developing unit holds toner or developer. A process cartridge, wherein the toner or developer is the toner according to any one of claims 1 to 7 or the developer according to claim 8 or 9. The fixing unit includes a heating body provided with a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film, and the film and the pressure member The image forming apparatus according to claim 11, wherein the image forming apparatus is a fixing device that heats and fixes a recording material on which an unfixed image is formed.

Images