JP2005215254A - Image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method by which high glossiness, no angle dependency of gloss, a wide color gamut, no unevenness in gloss and adaptability of a cleaningless process are ensured. <P>SOLUTION: In the image forming method, a toner and a fixing member used for fixing satisfy the following conditions (a) to (e); (a) in a molecular weight distribution of a component eluted from the toner by tetrahydrofuran, peaks are present between 14,000 and 18,000 and between 500 and 1,000, (b) a volume average particle diameter of the toner is 4.4-5.8 μm, (c) 2-3 endothermic peaks of the toner in temperature-rising measured by DSC are present at 50-73°C and an amount of heat absorbed at each peak is 12.6-24.5 J/mg, (d) 1-3 exothermic peaks in cooling measured by DSC are present at 45-70°C and the half value width of the highest exothermic peak in cooling is larger than that of the highest endothermic peak in temperature-rising, (e) the fixing member comprises a polyimide belt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming method in which an electrostatic image on an electrophotographic photosensitive member is developed with a developer containing toner, and transferred and fixed on paper to obtain an image.

  Full-color image forming methods in electrophotography were mostly used for color photocopying and design companies. However, in recent years, there has been an increasing number of cases where color multifunction machines that also serve as color printers and color copiers are introduced into offices. The background of this is the business of planning documents and reports, etc. by connecting each personal computer and a color multifunction device over the network as the cost of the equipment is reduced, miniaturized, speeded up, and IT is progressing in the office. One of the reasons is that documents are now output on color multifunction devices.

  In addition, by providing the toner with release performance, an “oilless color machine” that eliminates the need to supply oil such as silicone oil has been put on the market, and the smoothness of the image surface after fixing has been improved. A color image can be provided (see, for example, Patent Documents 1 and 2).

  With the spread of such oilless color machines, manufacturers have proposed a glossy finished color image with toner, but the user side also has a high need for high-gloss color images. In addition, the user's demand for expanding the color gamut of the toner image has been increasing day by day so that faithful color reproduction can be realized.

  As a means for satisfying the needs for such color images, a method of smoothing the toner image surface with wax by introducing an oilless toner obtained by adding a large amount of low melting point wax, A technique for reducing the melt viscosity of the toner and improving the mutual permeability between the yellow, magenta, and cyan toners has been proposed, but has not yet reached a level that can satisfy the user's needs.

  The technology of adding a large amount of wax to toner particles is advantageous over conventional pulverized toner because chemical toners typified by polymerized toners, which have been developed in recent years, have a high degree of freedom in adding wax during toner production. The technique of adding wax into the toner has reached its limit.

  In addition, it was confirmed that when toner containing a large amount of wax was used, it was very difficult to control the wax so that it exudes at an appropriate speed in the fixing process. That is, since the wax is rapidly discharged from the toner in the initial stage of fixing, the wax cannot be uniformly oozed throughout the fixing process. As a result, gloss unevenness appeared remarkably on the toner image after fixing. In particular, many high-speed machines in recent years add finishers, bookbinding devices, etc. to add post-processing to printed materials. However, when printed materials locally come into contact with the conveying members that make up these devices, There was also a problem that unevenness of gloss was generated between the portion where the touched portion was rapidly cooled and the rapidly cooled portion and the naturally cooled portion.

As described above, an image forming method that can uniformly exude the wax in the oilless toner in the fixing step has been desired.
JP-A-9-120225 JP-A-9-197882

  The present invention has been made in view of the above problems. In an image forming method for forming an image using an oilless toner obtained by adding a large amount of wax, the image forming method has high glossiness and gloss angle dependency. It is an object of the present invention to provide an image forming method that has a wide color gamut capable of faithful color reproduction and that eliminates uneven glossiness particularly in a high-speed machine. Furthermore, it is to improve the adaptability of the cleaningless process.

  The inventor has reexamined the relationship between the wax layer formed on the toner image and the occurrence of uneven gloss. Then, paying attention to the movement of light on the toner image formed after the fixing process, examining how the light acts on the toner image formed after the fixing process, one cause of occurrence of uneven glossiness As a result, it is assumed that a state where light is irregularly reflected is formed on the toner image.

  That is, the present inventor has light reflected by the wax layer formed on the surface of the toner image formed through the fixing process and light reflected by the interface between the colorant and the resin constituting the toner through the wax layer. However, it was speculated that diffuse reflection occurs due to the action of the reflected light and gloss unevenness occurs.

  Therefore, the present inventor considered that this problem can be solved by forming a wax layer that does not cause irregular reflection of light on the surface of the toner image. That is, it was confirmed that the present invention can be achieved by any of the configurations described below.

(Claim 1)
In an image forming method in which an electrostatic latent image on an electrophotographic photosensitive member is developed with a developer containing toner, and this is transferred to paper and fixed to obtain an image. An image forming method characterized by satisfying the above.

B) A peak exists between 11000 and 18000 and 500 to 2000 in the molecular weight distribution of the tetrahydrofuran elution of the toner. B) The volume average particle diameter of the toner is 4.4 to 5.8 μm.
C) There are 2 to 3 endothermic peaks at 50 to 73 ° C. when the temperature rises as measured by DSC of the toner, and the endothermic amount is 12.6 to 24.5 J / mg.
D) There are 1 to 3 exothermic peaks at 45 to 70 ° C during cooling as measured by DSC, and the half-value width of the maximum exothermic peak during cooling is greater than the half-value width of the endothermic maximum peak during temperature rise. The member is composed of a polyimide belt (Claim 2).
In the molecular weight distribution of the toner tetrahydrofuran elution, there are peaks between 14000 and 17000 and 500 to 1000, the valley formed by these two peaks is at 1200 to 3000, and the elution starting molecular weight is 100,000 to 1,500,000. The image forming method according to claim 1, wherein:

(Claim 3)
The average value of the circularity of the toner particles is 0.979 to 0.996, and there are 2 to 3 endothermic peaks at 50 to 71 ° C. at the time of temperature rise measured by DSC of the toner. The image forming method according to claim 1, wherein the image forming method is 4 to 24.5 J / mg.

  According to the present invention, in an image forming method for forming an image using an oilless toner to which a large amount of wax is added, a wide color which has high glossiness and does not depend on the angle of gloss and can reproduce faithful colors. Image forming method that eliminates the occurrence of uneven glossiness particularly in a high-speed machine, and can improve the suitability of the cleaning-less process.

  Hereinafter, the present invention will be described in detail.

  The present invention has been found that when the toner particle size, the molecular weight of the binder resin constituting the toner and the melting point of the wax are optimized, the toner has a tendency not to depend on its cooling history, and as a result, the fixing step. This solves the problem of uneven glossiness on a later toner image.

  The toner according to the present invention has the following properties (a) to (d).

B) A peak exists between 11000 and 18000 and 500 to 2000 in the molecular weight distribution of the tetrahydrofuran elution of the toner. B) The volume average particle diameter of the toner is 4.4 to 5.8 μm.
C) There are 2 to 3 endothermic peaks at 50 to 73 ° C. when the temperature rises as measured by DSC of the toner, and the endothermic amount is 12.6 to 24.5 J / mg.
D) There are 1 to 3 exothermic peaks during cooling as measured by DSC at 45 to 70 ° C., and the half-value width of the maximum exothermic peak during cooling is larger than the half-value width of the endothermic maximum peak during temperature rise.

  The exothermic peak at the time of cooling the toner has a tendency to generate a new peak or grow the exothermic peak on the low temperature side depending on the toner formulation even when the same wax is employed. Further, although there are a plurality of heat generation peaks when the toner is cooled, the present invention has found that there is a tendency to suppress the occurrence of uneven glossiness as the heat generation amount of the peak appearing on the low temperature side is smaller. It was. In addition, while investigating the generation tendency of the exothermic peak during cooling, the inventors have newly found that the peak during cooling varies depending on the type of colorant constituting the toner. The tendency is particularly prominent in magenta toner, and in the present invention, magenta toner according to the following two formulations (a) or (b) is suitable as a toner capable of forming a toner image that does not cause uneven glossiness. I found it.

  (A) A combination of a quinacridone pigment and a diketopyrrole and / or a strontium salt of a carmine pigment as a colorant.

  (B) As a colorant, C.I. I. Pigment Red 31 and C.I. I. Used in combination with Pigment Red 150. Preferably, both are mixed crystals.

  It has also been confirmed that toners using the colorants (a) and (b) can achieve a higher transfer rate than conventional magenta toners, and the toner particles have a circularity relatively close to a perfect circle. Specifically, when the average value of the circularity is 0.979 to 0.996, it has been confirmed that it can be suitably used for a cleaner-less process as disclosed in, for example, JP-A-2003-162130.

  The toner according to the present invention has a volume average particle size of 4.4 to 5.8 μm, preferably 4.7 to 5.4 μm. For example, in the case of an emulsion association type toner, the volume average particle diameter can be controlled by controlling the addition timing of the aggregation terminator when forming the resin particles, as will be described later. The volume average particle diameter is measured by attaching a 30 μm orifice to a sheath flow type particle size distribution measuring device SD2000 (manufactured by Sysmec).

  Further, the toner according to the present invention has 2 to 3 endothermic peaks measured by DSC at 50 to 73 ° C., the endothermic amount is 12.6 to 24.5 J / mg, and preferably the endothermic peak is 45. It is characterized by the presence of 1 to 3 at ˜70 ° C., and the half-value width of the maximum exothermic peak during cooling is larger than the half-value width of the maximum exothermic peak during temperature rise. The measurement method by DSC (differential calorimetry) is, for example, that the sample is allowed to stand at 0 ° C. for 1 minute, and then heated from 0 ° C. to 200 ° C. under the condition of 10 ° C./min. It detects temperature and the amount of heat. Specific examples of the differential calorimeter include DSC-7 manufactured by PerkinElmer.

  The binder resin constituting the toner used in the present invention has a peak between 14000 and 17000 and 500 to 1000 in the molecular weight distribution of tetrahydrofuran elution, and is formed by the two peaks. The trough is present at 1200 to 3000 and the elution starting molecular weight is 100,000 to 1,500,000. The above molecular weight is measured by GPC (gel permeation chromatography) using THF (tetrahydrofuran) as a column solvent.

(Average value of circularity of toner particles)
As described above, the shape of the toner particles used in the present invention has an average value of circularity (shape factor) represented by the following formula when 0.9 or more toner particles having a particle diameter of 1 μm or more are measured. The range is 0.996. When in this range, the toner filling density in the transferred image is increased and the heat conduction between the toner particles is improved, so that the melting of the toner proceeds and the penetration between the toners of each color is promoted. It is possible to enlarge the area.

Circularity = (perimeter of equivalent circle) / (perimeter of toner particle projection image)
= 2π × (particle projected area / π) ^1/2 / (periphery length of toner particle projected image)
Here, the equivalent circle is a circle having the same area as the toner particle projection image, and the equivalent circle diameter is the diameter of the equivalent circle. In addition, as a measuring method of the said circularity, it can measure by FPIA-1000 (made by Sysmec). At this time, the equivalent circle diameter is defined by the following equation.

Equivalent circle diameter = 2 × (projected area of particle / π) ^1/2
A method for producing a toner for developing an electrostatic image used in the present invention will be described.

  The toner used in the present invention is preferably a toner obtained by polymerizing at least a polymerizable monomer in an aqueous medium, and is a toner obtained by associating at least resin particles in an aqueous medium. It is preferable. That is, the polymer is emulsion-polymerized in a suspension polymerization method or in a liquid (in an aqueous medium) to which an emulsion of necessary additives is added to prepare fine polymer particles (resin particles). And a method of producing the resin particles by associating them by adding an organic solvent, a flocculant and the like. Here, “association” means that a plurality of the resin particles are fused, and includes a case where the resin particles and other particles (for example, colorant particles) are fused.

  The method for producing the toner particles used in the present invention is not particularly limited, but specifically, a resin particle is formed by emulsion polymerization, and the resin particles are assembled to form a toner particle dispersion. Examples thereof include a method for preparing a toner particle dispersion by a polymerization method, and includes, for example, a release agent formed through multistage polymerization as disclosed in JP-A-2002-49180 and JP-A-2002-131978. A method for producing toner particles by salting out / fusing the resin particles obtained in an aqueous medium (coagulation of the resin particles and disappearance of the interface between the resin particles at the same time), or JP-A-2000-131877 After the colorant particle dispersion and the release agent particle dispersion are mixed in the resin particle dispersion prepared by emulsion polymerization to form aggregated particles, the aggregated particles are heated and fused to form toner particles. Manufacture Law, and the like.

  As described above, the toner used in the present invention is produced by introducing a raw material into an aqueous medium, performing a polymerization reaction, and then performing an aging step.

  Further, the toner particles are solid-liquid separated from the toner particle dispersion liquid containing the toner particles obtained in the above process to prepare a toner cake, and the water cake is removed from the toner cake to remove deposits such as a surfactant. I do. Examples of the solid-liquid separation method include a centrifugal separation method using a rotating cylindrical dehydrator and the like, a vacuum filtration method using a Nutsche and the like, a filter press method, and the like. Of these, solid-liquid separation by centrifugation is preferred.

  The toner cake subjected to the water washing treatment is dried to become toner. The drying method is not particularly limited, but vacuum drying is preferred. Examples of the vacuum dryer include, but are not limited to, a vacuum spray dryer, a vacuum freeze dryer, and a vacuum dryer. Specifically, it is preferable to use a stationary shelf dryer, a movable shelf dryer, a fluidized bed dryer, a rotary dryer, a stirring dryer, or the like that can be decompressed.

  The toner used in the present invention is produced through the above steps.

  Next, the release agent contained in the toner used in the present invention will be described. As described above, the release agent used in the present invention is such that, when the toner is measured with DSC-7 or the like as described above, the toner acts to develop an endothermic peak at 58 to 73 ° C. There is no particular limitation.

  The content of the release agent constituting the toner used in the present invention is usually 10 to 30% by mass, preferably 12 to 20% by mass, and more preferably 15 to 20% by mass.

  Preferable mold release agents include ester compounds represented by the following general formula.

General formula R _1- (OCO-R ₂ ) _n
In the formula, n represents an integer of 1 to 4, preferably 2 to 4, more preferably 3 to 4, and particularly preferably 4.

R ₁ and R ₂ represent a hydrocarbon group which may have a substituent.

R ₁ : carbon number = 1-40, preferably 1-20, more preferably 2-5
R ₂ : carbon number = 1-40, preferably 16-30, more preferably 18-26
Specific examples of the ester compound represented by the above general formula are shown below. Among them, those having a melting point that causes the toner to exhibit an endothermic peak between 58 to 73 ° C., such as behenyl behenate and stearyl stearate, among others. preferable.

  A polymerizable monomer which is a resin material constituting the toner used in the present invention will be described.

(1) Hydrophobic monomer As a hydrophobic monomer which comprises a monomer component, it does not specifically limit and a conventionally well-known monomer can be used. Moreover, it can be used combining 1 type (s) or 2 or more types so that the required characteristic may be satisfy | filled.

  Specifically, monovinyl aromatic monomers, (meth) acrylic acid ester monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers , Halogenated olefin monomers and the like can be used.

  Examples of vinyl aromatic monomers include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples thereof include styrene monomers such as 4-dimethylstyrene and 3,4-dichlorostyrene and derivatives thereof.

  Examples of acrylic monomers include acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, methyl methacrylate, methacrylic acid. Examples include butyl acid, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like. Examples of vinyl ester monomers include vinyl acetate, vinyl propionate, and vinyl benzoate. Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

  Examples of the monoolefin monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like. Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

(2) Crosslinkable monomer A crosslinkable monomer may be added to improve the properties of the resin particles. Examples of the crosslinkable monomer include those having two or more unsaturated bonds such as divinylbenzene, divinylnaphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and diallyl phthalate.

(3) Monomer having an acidic polar group Monomers having an acidic polar group include (a) an α, β-ethylenically unsaturated compound having a carboxyl group (—COOH) and (b) a sulfone group (— Mention may be made of α, β-ethylenically unsaturated compounds having SO ₃ H).

Examples of the α, β-ethylenically unsaturated compound (a) having a —COO group include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, maleic acid monobutyl ester, maleic acid. Examples thereof include acid monooctyl esters and metal salts thereof such as Na and Zn. (B) Examples of α, β-ethylenically unsaturated compounds having a sulfo group (—SO ₃ H group) include sulfonated styrene, its Na salt, allylsulfosuccinic acid, allylsulfosuccinic acid octyl, its Na salt and the like. Can be mentioned.

  The initiator (also referred to as polymerization initiator) used for the polymerization of the polymerizable monomer according to the present invention will be described.

  The polymerization initiator used in the present invention can be appropriately used as long as it is water-soluble. For example, persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4′-azobis-4-cyanovaleric acid and its salts, 2,2′-azobis (2-amidinopropane) salts, etc.), Examples thereof include peroxide compounds such as hydrogen peroxide and benzoyl peroxide. Furthermore, the said polymerization initiator can be combined with a reducing agent as needed to make a redox initiator. By using a redox initiator, the polymerization activity is increased, the polymerization temperature can be lowered, and the polymerization time can be further shortened.

  The polymerization temperature may be any temperature as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. For example, a range of 50 ° C. to 80 ° C. is used. It is also possible to polymerize at or near room temperature by using a polymerization initiator that starts at room temperature, for example, a combination of hydrogen peroxide-reducing agent (such as ascorbic acid).

  The chain transfer agent used in the present invention will be described.

  In the present invention, conventionally known generally used chain transfer agents can be used for the purpose of adjusting the molecular weight of the resin particles produced by polymerization of the polymerizable monomer.

  The chain transfer agent is not particularly limited. In particular, a compound having a mercapto group is preferably used because a toner having a sharp molecular weight distribution can be obtained and storage stability, fixing strength, and offset resistance are excellent. For example, a compound having a mercapto group such as octanethiol, dodecanethiol, and tert-dodecanethiol is used. Preferred examples include ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, decyl thioglycolate, thioglycol Examples include dodecyl acid, thioglycolic acid ester of ethylene glycol, thioglycolic acid ester of neopentyl glycol, and thioglycolic acid ester of pentaerythritol. Among these, n-octyl-3-mercaptopropionic acid ester is preferably used from the viewpoint of suppressing odor during toner heat fixing.

《Colorant》
The colorant constituting the toner used in the present invention will be described.

  The colorant according to the toner for developing electrostatic images of each of the four colors of yellow, magenta, cyan, and black according to the present invention is the above-mentioned composite resin particle at the time of toner production from the viewpoint of improving the toner charge uniformity. It is preferable that the resin particles are salted out, agglomerated and fused together with the resin particles during salting out, agglomeration and fusion and contained in the colored particles.

  As described above, the colorant constituting the toner according to the present invention (colorant particles used for salting out, agglomeration, and fusion with the composite resin particles) in the magenta toner is a quinacridone pigment and a diketopyrrole pigment, or When a quinacridone pigment and a strontium salt of a carmine pigment are used in combination, a magenta toner having excellent color reproducibility can be obtained. In addition, various conventionally known inorganic pigments and organic pigments can also be used.

  Examples of black pigments for black toner include carbon blacks such as furnace black, channel black, acetylene black, thermal black, and lamp black, and neutral carbon such as legal 660 is particularly preferable. When neutral carbon is used, the incorporation of carbon black into the toner particles is improved and the release of carbon black from the toner particles is reduced. As a result, chargeability inhibition such as carrier contamination does not occur. In addition, the use of neutral carbon has the advantage of increasing the depth of the black image and increasing the gradation of the image.

  Specific examples of organic pigments that can be used in the toner according to the present invention include the following.

  In the present invention, the following organic pigments can be used in combination with the aforementioned colorant. Examples of organic pigments for magenta or red include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of organic pigments for orange or yellow used for the preparation of yellow toner include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 155, C.I. I. And CI Pigment Yellow 156.

  Examples of organic pigments for green or cyan used for preparing cyan toner include C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

  As the dye, C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 and the like. These dyes may be used alone or as a mixture of a plurality of dyes.

  Furthermore, these organic pigments and dyes can be used alone or in combination as desired. The content of the organic pigment or dye in the toner is preferably in the range of 2 to 20% by mass, more preferably in the range of 3 to 15% by mass.

  The colorant (colorant particle) according to the present invention may be surface-modified. Specific examples of the surface modifier include known silane coupling agents, titanium coupling agents, aluminum coupling agents, and the like. Things can be used.

  The addition amount of these surface modifiers is preferably in the range of 0.01 to 20% by mass, more preferably 0.1 to 5% by mass with respect to the colorant.

<Charge control agent>
The colored particles constituting the toner used in the present invention may contain an internal additive other than the release agent such as a charge control agent. Examples of the charge control agent contained in the colored particles include nigrosine dyes, naphthenic acid or higher fatty acid metal salts, alkoxylated amines, quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts, or metal complexes thereof. Is mentioned.

<Developer>
The developer used in the present invention will be described.

  The toner according to the present invention may be used as a one-component developer or a two-component developer. When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  Further, it can be mixed with a carrier and used as a two-component developer. In this case, conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead can be used as the magnetic particles of the carrier. Ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm. The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene-acrylic resin, silicone resin, ester resin, or fluorine-containing polymer resin is used. In addition, the resin for constituting the resin-dispersed carrier is not particularly limited, and a known resin can be used. For example, a styrene-acrylic resin, a polyester resin, a fluorine resin, a phenol resin, or the like is used. be able to.

<Photoconductor>
Next, the photoconductor used in the present invention will be described.

  The photoconductor used in the present invention is an electrophotographic photoconductor used for electrophotographic image formation, and the effect of the present invention is remarkably exhibited when an organic electrophotographic photoconductor (organic photoconductor) is used. An organic photoconductor means an electrophotographic photoconductor formed by providing an organic compound with at least one of a charge generation function and a charge transport function essential for the construction of an electrophotographic photoconductor. It contains all known organic electrophotographic photoreceptors such as a photoreceptor composed of a substance or an organic charge transport material, a photoreceptor composed of a polymer complex with a charge generation function and a charge transport function.

  The constitution of the organic photoreceptor used in the present invention is described below.

The conductive support used for the photoreceptor may be either a sheet or a cylinder, but a cylindrical conductive support is preferred for designing an image forming apparatus in a compact manner. Cylindrical conductive support means a cylindrical support necessary for forming an endless image by rotating. Conductivity is within a range of 0.1 mm or less in straightness and 0.1 mm or less in deflection. A support is preferred. Exceeding the roundness and shake range makes it difficult to form a good image. As the conductive material, a metal drum such as aluminum or nickel, a plastic drum deposited with aluminum, tin oxide, indium oxide or the like, or a paper / plastic drum coated with a conductive substance can be used. The conductive support preferably has a specific resistance of 10 ³ Ωcm or less at room temperature.

  Further, an intermediate layer having improved adhesion to the photosensitive layer and an electrical barrier function can be provided between the conductive support and the photosensitive layer. The film thickness of the intermediate layer using the curable metal resin is preferably in the range of 0.1 μm to 5 μm.

  The photosensitive layer configuration of the photoreceptor may be a single layer photosensitive layer configuration in which a charge generation function and a charge transport function are provided on one layer on the intermediate layer. More preferably, the function of the photosensitive layer is the charge generation layer. (CGL) and the charge transport layer (CTL) are preferably separated. By adopting a configuration in which the functions are separated, an increase in the residual potential due to repeated use can be controlled to be small, and other electrophotographic characteristics can be easily controlled according to the purpose. In the negatively charged photoconductor, it is preferable that a charge generation layer (CGL) is formed on the intermediate layer, and a charge transport layer (CTL) is formed thereon. In the positively charged photoconductor, the order of the layer configuration is the reverse of that in the negatively charged photoconductor.

  The structure of the photosensitive layer of the function-separated negatively charged photoreceptor will be described below.

  The charge generation layer contains a charge generation material (CGM). As other substances, a binder resin and other additives may be contained as necessary.

  A known charge generation material (CGM) can be used as the charge generation material (CGM). For example, a phthalocyanine pigment, an azo pigment, a perylene pigment, an azulenium pigment, or the like can be used. Among these, CGM that can minimize the increase in residual potential due to repeated use has a three-dimensional and potential structure that can form a stable aggregate structure among a plurality of molecules. Specifically, it is a phthalocyanine pigment, particularly a gallium phthalocyanine compound. Is preferred.

  Photoconductors using these gallium phthalocyanine compounds have high sensitivity at near-infrared semiconductor laser wavelengths (780 to 830 nm) and show stable electrical characteristics over a long period of time. Specific examples of gallium phthalocyanine compounds include strong diffraction peaks at 6.8 °, 12.8 °, 15.8 ° and 26.0 ° at the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum by CuKα. , And gallium phthalocyanine having strong diffraction peaks at 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 °, Mention may be made of chlorogallium phthalocyanine having strong diffraction peaks at 7.4 °, 16.6 °, 25.5 ° and 28.3 °.

  When a binder is used as the CGM dispersion medium in the charge generation layer, examples of the binder include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, and phenoxy resin. The proportion of the binder resin CGM is preferably 20 to 600 parts by mass with respect to 100 parts by mass of the binder resin. By using these resins, the increase in residual potential associated with repeated use can be minimized. The thickness of the charge generation layer is preferably 0.01 to 2 μm.

  The charge transport layer contains a charge transport material (CTM) and a binder resin that disperses and forms a CTM. Examples of the charge transport material (CTM) include triarylamine compounds, hydrazone compounds, styryl compounds, benzidine compounds, and butadiene compounds. In the present invention, when a benzidine compound or a triarylamine compound is used, the difference in dielectric constant in the photoconductor is eliminated by the action of these compounds, and latent image formation is improved. However, it was confirmed that the formation of a more vivid color image was promoted and the improvement of the above-described problems of the present invention was remarkably exhibited.

  As the benzidine compound, a compound represented by the following general formula (IV) is preferable.

In the formula, R ₁ and R ₁ ′ each represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ₂ , R ₂ ′, R ₃ and R ₃ ′ represent a hydrogen atom, an alkyl group and an alkoxy group, respectively. Represents a halogen atom or a substituted amino group. M, m ′, n, and n ′ each represent an integer of 1 or 2.

  Among the benzidine compounds represented by the general formula (IV), the compounds represented by the following general formula (IV-i) or general formula (IV-ii) described in JP-A-62-247374 are used. Is preferred.

In the formula, R ₅ , R ₅ ′, R ₆ and R ₆ ′ each represent a hydrogen atom or a methyl group, R ₇ and R ₇ ′ each represent an alkyl group having 2 or more carbon atoms, R ₈ and R ₈ 'represents a hydrogen atom, an alkyl group, an alkoxy group or a substituted amino group, respectively.

  When these compounds are used, the solubility with respect to a solvent and the compatibility with the said polycarbonate resin are high, and a uniform coating film is obtained. As a result, it is possible to form a uniform interface, and it is possible to produce an electrophotographic photosensitive member that has particularly high sensitivity and excellent repeatability.

  Moreover, as a triarylamine type compound, the compound represented by the following general formula (V) is preferable.

In the formula, R ₄ represents a hydrogen atom or a methyl group, Ar ₁ and Ar ₂ each represents a halogen atom, an alkyl group, an alkoxy group or an aryl group or a thienyl group which may have a substituted amino group, k means an integer of 1 or 2.

  Specific compounds of the benzidine compounds and triarylamine compounds represented by the above general formula are described in paragraph Nos. “0019 to 0024” of Japanese Patent No. 3250368, but are not limited thereto.

  As the binder resin in the charge transport layer, a copolymerized polycarbonate resin composed of repeating structural units represented by the following general formula (I), general formula (II) and general formula (III) is used.

In the formula, R represents a hydrogen atom, a methyl group or an aryl group, and X ₁ , X ₂ and X ₃ each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aryl-substituted alkyl group, or a cyclohexyl group, X ₄ and X ₅ each represent a hydrogen atom, an alkyl group, an alicyclic hydrocarbon group, an aryl group or an aryl-substituted alkyl group, or X ₄ and X ₅ together form a carbocyclic or lactone ring X ₄ and X ₅ are not the same as the group R and phenyl group in formula (I), and X ₆ represents a hydrogen atom or a methyl group.

Examples of X _{2 to} X ₅ in the general formula (II) include substituents described in Japanese Patent No. 3250368.

  In the present invention, the copolymer polycarbonate resin comprising the repeating structural units represented by the general formula (I), the general formula (II) and the general formula (III) has a viscosity average molecular weight in the range of 10,000 to 200,000. Can be used, and more preferably 20,000 to 100,000. When the viscosity average molecular weight is in the above range, if it is less than 10,000, an appropriate coating solution viscosity can be obtained, and a desired film thickness can be easily formed. Moreover, the formed coating film has sufficient mechanical strength, and good abrasion resistance is obtained. Further, a mixture of different types of polycarbonate resins or copolymerization may be used as long as the functions and effects exhibited by the copolymer polycarbonate resin are not impaired.

  Specific compounds of (I), (II) and (III) represented by the above general formula are described in paragraph Nos. “0029 to 0034” of Japanese Patent No. 3250368, but are not limited thereto. .

  The thickness of the charge transport layer is preferably adjusted to 5 to 15 μm on average, and more preferably 6 to 13 μm. Here, the film thickness of the charge transport layer can be measured using an eddy current film thickness measuring device EDDY560C (manufactured by HELMUT FISCHER GMBTE CO).

  Various resin layers can be provided as a protective layer of the photoreceptor. In particular, an organic photoreceptor having high mechanical strength can be obtained by providing a crosslinked resin layer.

  Next, the image forming apparatus used in the present invention will be described.

  First, a cleanerless electrophotographic image forming apparatus which is an example of an image forming apparatus preferably used in the present invention is shown in FIG. The image forming apparatus shown in FIG. 1 is a cleanerless electrophotographic full-color image forming apparatus having a contact charging device, an image carrier, a developing device, and an intermediate transfer member. Y (yellow), M (magenta), C (cyan) ) And K (black), each of which has an individual image carrier (1y, 1m, 1c, 1k) that forms toner images of four colors. As the image carrier, the above-described organic photoreceptor is preferably used.

  Each image carrier (1y, 1m, 1c, 1k) is uniformly charged by a respective charger (2y, 2m, 2c, 2k) and then modulated laser beam (Ly, Lm, Lc, Lk). As a result, an electrostatic latent image is formed on the surface. The electrostatic latent image formed on the surface of the image carrier (1y, 1m, 1c, 1k) is developed into a toner image by a developing device (3y, 3m, 3c, 3k). The developed toner image is transferred to each primary transfer roll (4ym, 4ck) in two colors. The toner image transferred by the primary transfer is transferred to the secondary transfer roll 5. The color toner images transferred to the secondary transfer roll 5 are collectively transferred onto the recording sheet P by the tertiary transfer roll 6. A positive bias is applied to the primary transfer roll, secondary transfer roll, and tertiary transfer roll by a power source (not shown) so that negative toner can be electrostatically transferred. Yes.

  In the image forming apparatus of FIG. 1, the toner remaining on the surface of the image carrier (1y, 1m, 1c, 1k) is substantially eliminated by increasing the transfer efficiency of the toner image in each transfer step as much as possible. The process is substantially unnecessary. As a result, the toner scraped off by the scraper 8 and stored in the BTR unit 9 is substantially reduced or eliminated, and the problem of waste toner can be solved.

  Next, FIG. 2 shows an intermediate transfer belt type tandem color image forming apparatus which is an example of the image forming apparatus used in the present invention. The image forming apparatus shown in FIG. 2 can be used as a copying machine, a laser beam printer, or the like. The image forming apparatus shown in FIG. 2 includes units 10Y, 10M, 10C, and 10Bk, a belt-shaped intermediate transfer body 16, transfer rollers 17Y, 17M, 17C, and 17Bk, a recording paper transport roller 18, and a fixing device 2. It has. In the present invention, the belt-shaped intermediate transfer member 16 is provided with the belt-shaped intermediate transfer member used in the present invention as the belt material. In the present invention, a polyimide resin is used as a belt material for the intermediate transfer member 16 and an endless belt of the fixing device 2 described later. The polyimide resin used for the belt material used in the image forming apparatus according to the present invention will be described later.

  The units 10Y, 10M, 10C, and 10Bk can be rotated at a predetermined peripheral speed (process speed) in the clockwise direction indicated by an arrow, respectively, and the photosensitive drums 11Y, 11M, 11C, and 11Bk (not shown, but the photosensitive drum has a flange). It is fixed.) Around the photosensitive drums 11Y, 11M, 11C, and 11Bk, corotron chargers 12Y, 12M, 12C, and 12Bk, exposure units 13Y, 13M, 13C, and 13Bk, and color developing units (yellow developing unit 14Y and magenta developing unit) 14M, cyan developing device 14C, black developing device 14Bk) and photoreceptor cleaners 15Y, 15M, 15C, and 15Bk, respectively.

  Four units 10Y, 10M, 10C, and 10Bk are arranged in parallel to the intermediate transfer belt 16, but an appropriate order is set according to the image forming method, such as the order of the units 10Bk, 10Y, 10C, and 10M. can do.

  The intermediate transfer belt 16 can be rotated by the backup roller 30 and the support rollers 31, 32, 33 in the counterclockwise direction indicated by the arrow at the same peripheral speed as the photosensitive drums 11 </ b> Y, 11 </ b> M, 11 </ b> C, 11 </ b> Bk. , 33 is disposed so that a part thereof is in contact with the photosensitive drums 11Y, 11M, 11C, and 11Bk. The intermediate transfer belt 16 is provided with a belt cleaning device 34. The support roller 31 plays the role of a tension roller and is arranged to be movable in the direction of the surface of the intermediate transfer belt 16 so that the tension of the intermediate transfer belt 16 can be adjusted.

  The transfer rollers 17Y, 17M, 17C, and 17Bk are disposed inside the intermediate transfer belt 16, and are respectively disposed at positions facing the portions where the intermediate transfer belt 16 and the photosensitive drums 11Y, 11M, 11C, and 11Bk are in contact with each other. The photosensitive drums 11Y, 11M, 11C, and 11Bk and a primary transfer portion (nip portion) for transferring a toner image to the intermediate transfer belt 16 are formed.

  The bias roller 35 is disposed on the surface side of the intermediate transfer belt 16 on which the toner image is carried so as to face the backup roller 30 with the intermediate transfer belt 16 interposed therebetween. The bias roller 35 and the backup roller 30 via the intermediate transfer belt 16 form a secondary transfer portion (nip portion). Further, the backup roller 30 includes an electrode roller 26 that rotates while being pressed against the backup roller 30.

  The fixing device 2 is disposed so that the recording sheet P can be conveyed after passing through the secondary transfer portion.

  In the image forming apparatus shown in FIG. 2, in the unit 10Y, the photosensitive drum 11Y is rotationally driven. In conjunction with this, the corotron charger 12Y is driven to uniformly charge the surface of the photosensitive drum 11Y to a predetermined polarity and potential. The photosensitive drum 11Y having a uniformly charged surface is exposed imagewise by the exposure device 13Y, and an electrostatic latent image is formed on the surface.

  Subsequently, when the electrostatic latent image is developed by the yellow developing device 14Y, a toner image is formed on the surface of the photosensitive drum 11Y.

  When the toner image passes through the primary transfer portion (nip portion) between the photosensitive drum 11Y and the intermediate transfer belt 16, an intermediate transfer belt 16 is generated by an electric field formed by a transfer bias applied from the transfer roller 17Y. The primary transfer is sequentially performed on the outer peripheral surface.

  Thereafter, the toner remaining on the photoreceptor drum 11Y is cleaned and removed by the photoreceptor cleaner 15Y. Then, the photosensitive drum 11Y is subjected to the next transfer cycle.

  The above transfer cycle is similarly performed in the units 10M, 10C, and 10Bk, and a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 16. As a result, a full-color toner image is formed.

  The full-color toner image transferred to the intermediate transfer belt 16 reaches the secondary transfer portion (nip portion) where the bias roller 35 is installed by the rotation of the transfer belt 16.

  The recording sheet P is fed at a predetermined timing between the intermediate transfer belt 16 and the bias roller 35 in the secondary transfer portion. The toner image carried on the intermediate transfer belt 16 is transferred onto the recording sheet P by the pressure conveyance by the bias roller 35 and the backup roller 30 and the rotation of the intermediate transfer belt 16.

  The recording sheet P to which the toner image has been transferred is conveyed to the fixing device 2 and the toner image is fixed by pressure / heating treatment. After the transfer, the intermediate transfer belt 16 is prepared for the next transfer by removing residual toner by a belt cleaning device 34 provided downstream of the secondary transfer portion.

  Polyimide resin is preferably used as a belt material for the intermediate transfer belt of the image forming apparatus and the endless belt of the fixing apparatus according to the present invention.

  Next, the fixing device 2 preferably used in the present invention will be described. In the following description, the “heat fixing roller” is simply referred to as “fixing roller”.

  Next, the fixing device 2 (FIG. 3) provided in the image forming apparatus of FIG. 2 used in the present invention will be described. FIG. 3 is a cross-sectional configuration diagram showing an example of the form of the fixing device used in the present invention.

  In FIG. 3, a fixing roller 10, an endless belt 11, a pressure pad (pressure member) 12 a that is pressed against the fixing roller 10 via the endless belt 11, a pressure pad (pressure member) 12 b, and the lubricant supply member 40. The main part is composed.

  The fixing roller 10 is formed by forming a heat-resistant elastic body layer 10b and a release layer (heat-resistant resin layer) 10c around a metal core (cylindrical core) 10a. A halogen lamp 14 is disposed as a heating source. The temperature of the surface of the fixing roller 10 is measured by the temperature sensor 15, and the halogen lamp 14 is feedback-controlled by a temperature controller (not shown) based on the measurement signal so that the surface of the fixing roller 10 is adjusted to a constant temperature. The endless belt 11 is in contact with the fixing roll 10 so as to be wound at a predetermined angle, thereby forming a nip portion.

  Inside the endless belt 11, a pressure pad 12 having a low friction layer on its surface is disposed in a state of being pressed against the fixing roller 10 via the endless belt 11. The pressure pad 12 is provided with a pressure pad 12a to which a strong nip pressure is applied and a pressure pad 12b to which a weak nip pressure is applied, and is held by a holder 12c made of metal or the like.

  Further, a belt traveling guide is attached to the holder 12c so that the endless belt 11 can smoothly slide and rotate. The belt traveling guide is preferably a member having a low coefficient of friction because it rubs against the inner surface of the endless belt 11, and a member having low heat conduction is preferable so that heat is not easily taken from the endless belt 11.

  The fixing roller 10 is rotated in the direction of arrow B by a motor (not shown), and the endless belt 11 is also rotated by this rotation. The toner image 17 is transferred onto the recording medium 16 by a transfer device (not shown), and the recording medium 16 is conveyed from the right side of the drawing toward the nip portion (in the direction of arrow A). The toner image 17 on the recording medium 16 inserted through the nip portion is fixed by the pressure acting on the nip portion and the heat applied through the fixing roller 10 by the halogen lamp 14. If fixing is performed by the apparatus having the configuration shown in FIG. 1, a wide nip portion can be taken, so that stable fixing performance can be ensured.

  The recording medium 16 after fixing is peeled off satisfactorily without being wound around the fixing roller 10 due to both effects of the release layer 10c and the distortion at the nip portion. It is desirable to provide the peeling means 20 downstream of the nip portion. The peeling unit 20 is configured to be held by a guide 20 b in a state where the peeling sheet 20 a is in contact with the fixing roller 10 in a direction opposite to the rotation direction of the fixing roller 10 (reverse).

  Hereinafter, each configuration will be described in detail. As the core 10a, a metal cylindrical body having high thermal conductivity such as iron, aluminum, and stainless steel can be used. Regarding the outer diameter and thickness of the core 10a, since the pressing force of the pressure pad 12 is small in the fixing device used in the present invention, one having a small diameter or one having a thin wall can be used. In this case, an outer diameter of about 20 to 35 mm and a thickness of about 0.3 to 0.5 mm can be used. Of course, since the strength and thermal conductivity differ depending on the material used, the optimum dimensions may be determined as appropriate.

  Any material can be used as the heat-resistant elastic layer 10b formed on the surface of the core 10a as long as it is an elastic body having high heat resistance. In particular, it is preferable to use an elastic body such as rubber or elastomer having a rubber hardness of about 25 to 40 ° (JIS-A), and specific examples include silicone rubber and fluorine rubber. The thickness of the heat resistant elastic layer 10b is preferably about 0.3 to 1.0 mm, although it depends on the rubber hardness of the material used.

  In the fixing device used in the present invention, a wide nip portion provides sufficient fixing performance, and effective releasability can be obtained with a small amount of distortion, so that the total load by the pressure pad 12 is small. In addition, the heat-resistant elastic layer 10b can be thinned. As described above, the fixing device used in the present invention can reduce the outer diameter of the core 10a, reduce the thickness, and reduce the thickness of the heat-resistant elastic layer 10b formed on the surface of the core 10a. Compared to the roll-pair type fixing device, the heat capacity is extremely low, the instant start property is improved, and / or the output of the halogen lamp 14 as a heating source can be reduced, and between the inner surface and the outer surface of the fixing roller 10. The thermal resistance can be reduced and the thermal response is accelerated. Therefore, power consumption can be reduced and faster fixing can be achieved.

  As the release layer (heat resistant resin layer) 10c formed on the heat resistant elastic layer 10b, any resin may be used as long as it is a heat resistant resin. For example, a fluororesin, a silicone resin, etc. Is mentioned. It is particularly preferable to use a fluororesin considering the releasability and wear of the release layer 10c. As the fluororesin, fluororesins such as PFA (perfluoroalkyl vinyl ether copolymer resin), PTFE (polytetrafluoroethylene), FEP (tetrafluoroethylene hexafluoropropylene copolymer resin) can be used. PFA is optimal from the viewpoints of workability and workability. The thickness of the release layer 10c is preferably 5 to 30 μm, more preferably 10 to 20 μm. If the thickness of the release layer 10c is less than 5 μm, wrinkles based on the distortion of the fixing roller 10 may occur, and if it exceeds 30 μm, the release layer 10c becomes hard and image quality defects such as uneven gloss are caused. May appear, both are undesirable. As a method for forming the release layer 10c, any conventionally known method can be employed, and examples thereof include a dip coating method, a spray coating method, a roll coating method, a bar coating method, and a spin coating method.

  The endless belt 11 is preferably composed of a base layer and a release layer coated on the surface (the surface in contact with the fixing roll 10 or both surfaces). The base layer is selected from polyimide, polyamide, polyamideimide and the like, and the thickness thereof is preferably about 50 to 125 μm, more preferably about 75 to 100 μm. The release layer formed on the surface of the base layer is preferably a coating of fluororesin as described above, for example, PFA or the like with a thickness of 5 to 20 μm.

  The winding angle of the endless belt 11 around the fixing roll 10 is preferably about 20 to 45 ° so as to ensure a sufficiently wide nip portion, although it depends on the rotation speed of the fixing roll 10. Also, the due time of the nip portion (recording medium insertion time) is 30 msec. In particular, 50 to 70 msec. It is preferable to set the wrapping angle to a degree. Thus, by using the endless belt 11 that can follow and follow the shape of the fixing roll 10, the width of the nip portion can be widened, and the toner fixing property and releasability can be improved. it can.

  As a basic configuration of the pressure pad 12, a pressure pad 12a having a weak nip pressure for securing a wide nip portion is provided on the inlet side of the nip portion to obtain a strong nip pressure with the fixing roller 10. 12b is respectively arranged on the outlet side of the nip portion. Further, in order to reduce the sliding resistance between the inner peripheral surface of the endless belt 12 and the pressure pad 12, a low friction layer is provided on the surface of the pressure pad 12a and the pressure pad 12b in contact with the endless belt 12. The nip member 12b is made of the same material as 12b.

  In the present invention, a lubricant may be applied between the surface of the pressure pad 12 and the inner surface of the endless belt 11. For example, silicone oil, fluorine oil, grease or the like is used. This lubricant is applied to the inner surface of the belt. However, since there is a possibility that the lubricant will go around the endless belt 11 and adhere to the fixing roll, it is desirable to have a releasability. Furthermore, silicone oil is preferable to fluorine oil in view of safety issues.

  Examples of the silicone oil include dimethyl silicone oil, amino-modified silicone oil, carboxy-modified silicone oil, silanol-modified silicone oil, and sulfonic acid-modified silicone oil. Among these, amino-modified silicone oil having a viscosity of 500 to 10000 cs is preferable in that the starting torque and driving torque of the image fixing device can be effectively maintained in a desired low range, and the handleability is excellent. Although the lubricant is not consumed, it may wrap around as described above when used for a long period of time, and may gradually decrease and eventually be exhausted. At this time, the torque increases. Therefore, the present invention includes the lubricant supply member 40 that holds and supplies the lubricant corresponding to the life of the fixing device so that the lubricant does not run out.

  The lubricant holding member 41 of the lubricant supply member 40 preferably has a large number of continuous pores, has heat resistance at the fixing temperature and has an appropriate elastic modulus, and examples thereof include felts and sponges. The lubricant permeation restriction film 42 of the lubricant supply member 40 has a large number of continuous pores, has heat resistance at a fixing temperature and a small friction coefficient, for example, has heat resistance and a friction coefficient. A film obtained by stretching and molding a small resin is preferable, and a film obtained by stretching and molding a fluororesin is preferable.

  The lubricant holding member 41 is impregnated with a lubricant, and the lubricant permeation amount regulating film 42 of the lubricant supply member 40 is in contact with almost the entire region in the axial direction of the endless belt. Then, as the endless belt 11 rotates, the lubricant is supplied to the entire inner peripheral surface of the endless belt 11. The supply amount of the lubricant does not need to be large. Therefore, the contact pressure of the lubricant supply member 40 with respect to the endless belt 11 is small and may be finely contacted.

  It is important to continue supplying a minute amount of the lubricant to the inner peripheral surface of the endless belt 11 over a long period of time. The amount of lubricant supplied to the inner peripheral surface of the endless belt 11 is regulated by changing the porosity of the porous lubricant permeation amount regulating film 42, thereby regulating the lubricant permeation amount in the lubricant permeation amount regulating membrane 42. To do.

  In the lubricant supply member 40, it is desirable that the lubricant supply amount in the vicinity of the central portion in the axial direction of the endless belt 11 is larger than the lubricant supply amount in the vicinity of the end portion in the axial direction of the endless belt 11. This is because the contact width of the lubricant supply member 40 near the center of the endless belt 11 is wider than the end, or the contact pressure of the lubricant supply member 40 near the center is stronger than the end. It is possible by doing. The supply amount is increased by making the contact width of the central portion of the lubricant supply member 40 wider than the end portion. This affects wrinkles when the endless belt 11 rotates. If the belt speed at the center is higher than the end speed, the belt does not wrinkle. However, if the belt speed at the center is lower than the end speed, the belt tends to wrinkle. Therefore, by making the supply amount of the lubricant larger in the central portion than in the end portion, the central portion of the belt can easily travel and wrinkles are prevented.

  The lubricant supply member 40 is attached to the outer surface of the belt traveling guide and is in weak contact with the inner peripheral surface of the endless belt 11. The lubricant supply member 40 is disposed in the vicinity of the nip entrance. On the nip portion entrance side, a force that presses the belt against the travel guide by the rotation of the endless belt 11 works, and therefore, by providing the lubricant supply member 40 here, the belt can be pressed without escaping.

  The polyimide resin has a feature that the deformation of the belt at the time of driving is small as compared with a conventionally used thermoplastic resin.

Examples of such belt materials include polypyromellitic acid imide resin materials such as Kapton HA manufactured by DuPont Co., Ltd., polybiphenyltetracarboxylic acid imide resin materials such as Upilex S manufactured by Ube Industries, Ltd., Ube Polybenzophenone tetracarboxylic imido acid resin materials such as Upilex R manufactured by Kosan Co., Ltd., and LARC-TPI (thermoplastic polyimide resin) manufactured by Mitsui Toatsu Chemical Industries, Ltd. can be exemplified. All of these have a Young's modulus of 3430 N / mm ² or more, and can satisfy the mechanical properties as a belt substrate with a thickness of 70 μm to 100 μm.

  A polyimide resin is generally a polymer synthesized by condensation polymerization using tetracarboxylic dianhydride and diamine or diisocyanate as monomer components. Examples of the tetracarboxylic acid component of the dianhydride include pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5, 6-biphenyltetracarboxylic acid, 2,2 ', 3,3'-biphenyltetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 3,3 ', 4,4'-diphenyl ether tetracarboxylic acid Acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid, bis ( 2,3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4 Radical Po hydroxyphenyl) hex-off Oro propane.

  Examples of the diamine component include m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine, p-xylylenediamine, 1, 4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4'-diaminonaphthalebiphenyl, benzidine, 3,3-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,4 ' -Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA), 4,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzophenone, 4,4'-diaminophenyl sulfone, 4,4'-diaminoazobenzene, 4,4'-diamy Diphenylmethane, beta, beta-bis (4-amine phenyl) propane. The compound which substituted the amino group in the above-mentioned diamine component made into the said isocyanate component with the isocyanate group is mentioned. Commercially available products of these polyimides include, for example, pyromellitic acid-based polyimide (Kapton HA: manufactured by DuPont) having diamine as a diamine component, and 3,3 ′, 4,4′-biphenyltetracarboxylic acid-based polyimide (Upilex S). : Ube Industries, Ltd.) and the like.

  In addition, the polyimide resin used in the present invention satisfies, for example, the relational expression between the Young's modulus and the amount of displacement of the belt due to the load at the time of driving the belt described in Japanese Patent Laid-Open No. 2000-338778, or It may have a contact angle with a water droplet disclosed in Japanese Patent No. -231684 and a mechanical property of surface resistivity.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these embodiments.

Example 1
(Preparation of low molecular weight resin particles)
Resin particle dispersion (L1)
Styrene 322.3g
n-Butyl acrylate 121.9g
Methacrylic acid 35.5g
A surfactant solution was prepared by dissolving 2.5 g of anionic surfactant (101) in 1340 g of ion-exchanged water in a 5000 ml separable equipped with a stirrer, a temperature sensor, and a cooling pipe. After the surfactant solution is heated to 80 ° C., the polymerizable monomer solution is mixed and dispersed for 2 hours by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. Thus, an emulsion (dispersion) containing emulsion particles (oil droplets) having a dispersion particle size (182 nm) was prepared.

  Next, after adding 1460 ml of ion-exchanged water, an initiator solution in which 7.5 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 142 ml of ion-exchanged water and 22.6 g of n-octanethiol were added, The system was polymerized by heating and stirring at 80 ° C. for 3 hours to obtain resin particles (a dispersion of low molecular weight resin particles).

[Production of toner]
<Toner C-1>
(Preparation of resin particle dispersion)
Production of Resin Particles In a flask equipped with a stirrer, a release agent (88 parts by mass of stearyl stearate, 6 parts by mass of behenyl stearate, 3 parts by mass of stearyl behenate, 162.0 g of behenyl acid (3 parts by mass) was added, heated to 75 ° C. and dissolved. This is designated as a polymerizable monomer solution 1-1.

Styrene 172.9g
n-Butyl acrylate 55.0g
Methacrylic acid 23.1g
Meanwhile, 2.5 g of anionic surfactant (101: C ₁₂ H ₂₅ (OCH ₂ CH ₂ ) ₂ OSO ₃ Na) was added to 1340 g of ion-exchanged water in a 5000 ml separable equipped with a stirrer, a temperature sensor, and a cooling pipe. A surfactant solution was prepared by dissolution. After the surfactant solution is heated to 80 ° C., a polymerizable monomer solution 1-1 is prepared by using a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. An emulsified liquid (dispersed liquid) containing emulsified particles (oil droplets) having a dispersed particle diameter (482 nm) was prepared by mixing and dispersing for a time.

  Next, after adding 1460 ml of ion-exchanged water, an initiator solution in which 7.5 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 142 ml of ion-exchanged water and 6.74 g of n-octanethiol were added, This system was heated and stirred at 80 ° C. for 3 hours to perform polymerization (first stage polymerization) to obtain resin particles (a dispersion of high molecular weight resin particles). This is designated as “resin particles (1-1)”.

  To this was added an initiator solution in which 11.6 g of a polymerization initiator (KPS) was dissolved in 220 ml of ion-exchanged water, and then the following polymerizable monomer solution 1-2 was added under a temperature condition of 80 ° C. The solution was added dropwise over 1 hour.

(Polymerizable monomer solution 1-2)
291.2 g of styrene
n-Butyl acrylate 132.2g
Methacrylic acid 42.9g
n-Octanethiol 12.52g
After completion of dropping, polymerization (second-stage polymerization) is carried out by stirring for 2 hours, followed by cooling to 28 ° C. and dispersion of resin particles (1-2) using resin particles (1-1) as raw materials. A liquid was obtained.

(Preparation of colorant dispersion)
Anionic surfactant (101) 59.0 g was dissolved in 1600 ml of ion-exchanged water with stirring. I. Pigment Blue 15: 1 280.0 g was gradually added, followed by dispersion treatment using “CLEARMIX” (manufactured by M Technique Co., Ltd.) to prepare a dispersion of colorant particles. The particle diameter of this colorant dispersion was 93 nm. This is designated as Colorant Dispersion Liquid c-1.

(Meeting process)
259.3 g of resin particles (1-2) (in terms of solid content), 3.9 g of resin particle dispersion (L1) in terms of solid content, 1120 g of ion-exchanged water, and 237 g of the above colorant dispersion, The mixture was stirred in a four-necked flask equipped with a temperature sensor, a condenser, a nitrogen introducing device, and a stirring device. After adjusting the temperature in the container to 30 ° C., the pH was adjusted to 10 by adding a 5 mol / liter sodium hydroxide aqueous solution.

  Subsequently, 20.1 g of polyaluminum chloride 10 mass% aqueous solution was added over 10 minutes at 30 degreeC under stirring. After standing for 3 minutes, the temperature was raised and the system was heated to 90 ° C. over 60 minutes to associate the resin particles (1-2) with the colored particles.

  While continuing stirring and heating, the particle size of the colored particles m1 as the inner layer was measured with “Coulter Counter TA-II” (manufactured by Beckman Coulter), and when the volume average particle size became 4.5 μm, An aqueous solution in which 15.3 g of sodium chloride was dissolved in 100 ml of ion-exchanged water was added to suppress particle growth.

  Heating and stirring were continued for about 1 hour or more, and when the circularity reached 0.944, the outer layer resin particle dispersion (S1) to be described later was added in quarters in four portions, and the associated surface was added. The outer layer resin particles s1 were moved and fused. Finally, the circularity after addition of the outer layer resin particles s1 was 0.995. The product obtained here is referred to as toner particle dispersion C-1.

Resin particle dispersion for outer layer (S1)
Styrene 322.3g
n-Butyl acrylate 121.9g
Methacrylic acid 35.5g
A surfactant solution was prepared by dissolving 2.5 g of anionic surfactant (101) in 1340 g of ion-exchanged water in a 5000 ml separable equipped with a stirrer, a temperature sensor, and a cooling pipe. After the surfactant solution is heated to 80 ° C., the polymerizable monomer solution is mixed and dispersed for 2 hours by a mechanical disperser “CLEARMIX” (manufactured by M Technique Co., Ltd.) having a circulation path. Thus, an emulsion (dispersion) containing emulsion particles (oil droplets) having a dispersion particle size (182 nm) was prepared.

  Next, after adding 1460 ml of ion-exchanged water, an initiator solution in which 7.5 g of a polymerization initiator (potassium persulfate: KPS) was dissolved in 142 ml of ion-exchanged water and 22.6 g of n-octanethiol were added, The system was polymerized by heating and stirring at 80 ° C. for 3 hours to obtain resin particles (a dispersion of low molecular weight resin particles).

(Solid-liquid separation, drying process)
The dispersion of toner particles C-1 was applied to a centrifugal dehydrator, washed while sprinkling with ion exchange water at 40 ° C., and then dried with warm air at 40 ° C. to obtain toner particles C-1.

(External additive mixing process)
In the toner particles C-1, 0.8 parts by mass of hydrophobic silica having a primary particle diameter of 14 nm, 1.0 part by mass of hydrophobic titanium oxide having a needle shape, 1.0 part by mass of hydrophobic silica having a primary particle diameter of 85 nm, Primary particle size 140 nm Hydrophobic silica 1.0 part by mass, oleic acid 0.11 part by mass, palmitic acid 0.05 part by mass, stearic acid 0.07, myristylate 0.03 was added, rotation of Henschel mixer The peripheral speed of the wing was set to 30 m / sec and mixed for 25 minutes. As a result, toner C-1 composed of toner particles C-1 was produced. Table 2 shows the average value of the circularity of the toner particles after mixing the external additive, the volume average particle diameter of the toner, the endothermic peak temperature measured by DSC, the endothermic amount, and the peak of the molecular weight distribution.

<Toner M-1>
In Toner C-1 (Preparation of Colorant Dispersion), C.I. I. Pigment Blue 15: 1, instead of 280.0 g, C.I. I. Toner M-1 was obtained in the same manner except that Pigment Red 184, 420 g was used.

<Toner Y-1>
In Toner C-1 (Preparation of Colorant Dispersion), C.I. I. Pigment Blue 15: 1, instead of 280.0 g, C.I. I. Toner Y-1 was obtained in the same manner except that Pigment Yellow 74, 420 g was used.

<Toner Bk-1>
In Toner C-1 (Preparation of Colorant Dispersion), C.I. I. Toner Bk-1 was obtained in the same manner except that 420 g of neutral carbon black legal 660 (manufactured by Cabot) was used instead of Pigment Blue 15: 1, 280.0 g.

<Toner C-2>
Toner C-1 was prepared in the same manner as in the preparation of toner C-1, except that 12.84 g of n-octanethiol added in the second stage polymerization, that is, the preparation of resin particles (1-2) was changed to 10.84 g. 2 was obtained.

<Toner M-2>
In the preparation of the toner C-2, C.I. I. Pigment Blue 15: 1, Toner M-2 was obtained in the same manner except that 40 g of the following compound was used as a magenta pigment instead of 280.0 g.

<Toner Y-2>
In Toner C-2 (Preparation of Colorant Dispersion), C.I. I. Pigment Blue 15: 1, instead of 280.0 g, C.I. I. Toner Y-2 was obtained in the same manner except that Pigment Yeiow 74 and 420 g were used.

<Toner Bk-2>
In Toner C-2 (Preparation of Colorant Dispersion), C.I. I. Pigment Blue 15: 1 Toner Bk-2 was obtained in the same manner except that 420 g of neutral carbon black legal 660 (manufactured by Cabot) was used instead of 280.0 g.

<< Comparative Toners c-1 to bk-1 >>
In the preparation of Toner C-1, 162.0 g of a release agent (88 parts by mass of stearyl stearate, 6 parts by mass of behenyl stearate, 3 parts by mass of stearyl behenate, 3 parts by mass of behenyl behenate) was added. A comparative toner c-1 was obtained in the same manner except that the acid-modified paraffin wax having a melting point of 97 ° C. was changed to 162 g. Similar changes were made to toners M-1 to Bk-1 to obtain comparative toners m-1 to b-k1.

<< Comparative Toners c-2 to bk-2 >>
In the preparation of the toner C-1, the composition of the release agent is as shown in Table 1. Further, 12.52 g of n-octanethiol was added during the second stage polymerization, that is, in the production of the resin particles (1-2). The toner c-2 was obtained in the same manner except that the toner was changed to 6.89 g. Similar changes were made to obtain comparative toners m-2 to bk-2.

<< Comparative Toners c-3 to bk-3 >>
In the preparation of the toner C-1, the composition of the release agent is as shown in Table 1. Further, 12.52 g of n-octanethiol was added during the second stage polymerization, that is, in the production of the resin particles (1-2). Was obtained in the same manner as above except that the amount was changed to 14.73 g. The same changes were made to obtain comparative toners m-3 to bk-3.

(Development of developer)
A carrier was produced as follows. A ferrite core material having a volume average particle size of 40 μm and a coating layer forming solution are combined, and a blend of 1,000 parts by mass of the ferrite core material and the following coating layer forming solution is vacuum degassed kneader (with an inner wall of 100 ° C. The mixture was stirred for 15 minutes, and then the solvent was distilled off under reduced pressure to obtain a carrier having a coating layer formed on the core particles.

Toluene 150 parts by mass MMA 24.1 parts by mass Carbon black 6.0 parts by mass Cross-linked styrene fine particles of 0.3 μm 4.0 parts by mass 3,3,4,4,5,5,6,6,7,7,8 , 8,9,9,10,10,10-heptadecafluorodecyl methacrylate 2.0 parts by mass Each toner and the above carrier were mixed to a toner concentration of 6% by mass to obtain a two-component developer.

[Production of photoconductor]
Photoconductors used in the examples were produced as follows (the photoconductors in each example were produced in a total of four or more because each image unit uses the same type of photoconductor).

  The following intermediate layer coating solution was prepared and applied on a washed cylindrical aluminum substrate by a dip coating method to form an intermediate layer having a dry film thickness of 0.3 μm.

<Intermediate layer (UCL) coating solution>
Polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) 60 g
1600 ml of methanol
The following coating solution components were mixed and dispersed for 10 hours using a sand mill to prepare a charge generation layer coating solution. This coating solution was applied by a dip coating method to form a charge generation layer having a dry film thickness of 0.2 μm on the intermediate layer.

<Charge generation layer (CGL) coating solution>
Y-type titanyl phthalocyanine (Maximum peak angle of X-ray diffraction by Cu-Kα characteristic X-ray is 27.3 at 2θ) 60 g
700 g of silicone resin solution (KR5240, 15% xylene-butanol solution: manufactured by Shin-Etsu Chemical Co., Ltd.)
2-butanone 2000ml
The following coating solution components were mixed and dissolved to prepare a charge transport layer coating solution. This coating solution was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 20 μm.

<Charge transport layer (CTL) coating solution>
Charge transport material (4-methoxy-4 '-(4-methyl-α-phenylstyryl) triphenylamine) 200 g
Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company) 300g
Hindered amine (Sanol LS2626: Sankyosha) 3g
1,2-dichloroethane 2000ml
<Surface protective layer>
Charge transport material (4-methoxy-4 '-(4-methyl-α-phenylstyryl) triphenylamine) 200 g
Bisphenol Z-type polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company) 300g
Hindered amine (Sanol LS2626: Sankyosha) 3g
100 g of polytetrafluoroethylene resin particles (average particle size 0.5 μm)
1-butanol 50g
Were mixed and dissolved to prepare a surface protective layer coating solution. This coating solution was applied onto the charge transport layer by a dip coating method, followed by heat curing at 100 ° C. for 40 minutes to form a surface protective layer having a dry film thickness of 4 μm, thereby preparing a photoreceptor.

(Live-action evaluation)
Using a commercially available full-color multifunction peripheral C2425 (manufactured by Fuji Xerox Co., Ltd.) that employs an electrophotographic system, a live-action test was performed, and the following evaluation items were evaluated. A dimethyl silicone oil having a viscosity of 3 Pa · s was applied to the inner wall of the fixing pressure member.

  In addition, the photosensitive member and the intermediate transfer pair were evaluated without a cleaning blade and a cleaning brush.

(Gloss unevenness)
A: Gloss unevenness cannot be detected at all. ○: Gloss unevenness cannot be detected at all unless magnified with a loupe. X: Streaky gloss unevenness can be detected visually.

(Gloss angle dependence)
Solid images of Y, M, C, R, G, and B were produced and evaluated according to the following criteria.

◎: When viewed from the front, the impression of oblique 45 ° C light and that seen from 45 ° backlit do not change. ○: When the image is viewed from the front, high gloss is felt, but from oblique 45 ° C light. What is seen, seen from oblique 45 ° backlight, glossiness is slightly different only by gazing. ×: When viewed from the front, the impression seen from oblique 45 ° forward light, viewed from oblique 45 ° backlight Changes.

(Glossiness matching)
An A3 size image with a pixel rate of 50% was formed on the following three types of transfer papers having different glossiness, and the gloss difference between the solid image portion and the white portion (that is, the transfer paper surface where no toner is present) was visually evaluated.

(1) Glossy paper POD super gloss 170 (manufactured by Oji Paper Co., Ltd.) Basis weight 128g / m ² , thickness 0.17mm
(2) Semi-glossy paper POD Super Gloss 100 (manufactured by Oji Paper Co., Ltd.) Basis weight 100 g / m ² , thickness 0.1 mm
(3) Matte paper POD matte coat 100 (manufactured by Oji Paper Co., Ltd.) Basis weight 100 g / m ² , thickness 0.1 mm
A: Three types of transfer papers with different glossiness do not feel the difference between the gloss of the solid image portion and the white portion (transfer paper surface), and there is no sense of incongruity. That is, a glossy toner image is obtained on glossy paper, a semi-glossy toner image is obtained on semi-glossy paper, and a matte toner image is obtained on matte paper. However, the glossiness of the toner image is insufficient on glossy paper, and the glossiness of the toner image is conspicuous on the matte image. The image has a sense of incongruity and does not feel a three-dimensional effect.

(Color gamut)
The fixing temperature of each image forming apparatus is set to 140 ° C., and each primary color of magenta (M), cyan (C), and yellow (Y) and each primary color are superposed in a 1: 1 ratio. , Blue (B) and green (G) were output. Art paper (Mitsubishi Paper Co., Ltd., Tokishi Art) and Fuji Xerox Office Supply Co., Ltd. C2r (smoothness 28) were used as the paper. Japan Color (Japan Color) was selected as a standard color in Japan by the Japan National Committee of the International Organization for Standardization Printing Technology Committee (ISO / TC130). The selection is made by collecting one piece each of the most common sheet-fed lithographic process inks from eight representative ink manufacturers in Japan, and measuring the color values of each color developed under the same conditions. The selected Japan Color (Japan Color) was submitted to the International Standards Organization Printing Technology Committee (ISO) in 1990. Later, it was revised and Japan Color 2002 is now the color standard in Japan. Standard color swatches are supplied by the Japan National Committee of the International Organization for Standardization Printing Technology Committee (ISO / TC130) and are readily available.

A: A color gamut equivalent to that of Japan Color 2002 was shown. O: A color reproducibility close to that of Japan Color 2002 was possible, but strictly, it did not reach the color gamut of Japan Color 2002. X: The color gamut was significantly narrower than that of Japan Color 2002. It is had.

(Compatibility with cleaningless process)
A: High transferability and no waste toner cleaned from the photosensitive member and intermediate transfer member is generated. ○: The photosensitive member does not require cleaning, and only the intermediate transfer member requires a cleaning member. X: Both the photosensitive member and intermediate transfer member require a cleaning member.

  From Table 3, it can be seen that the toner combination according to the present invention is superior to the comparison in all the evaluation items.

It is the schematic of the cleanerless system used for this invention. 1 is a schematic configuration diagram illustrating an example of an intermediate transfer belt type image forming apparatus used in the present invention. FIG. 2 is a side sectional view showing a form of a fixing device used in the present invention.

Explanation of symbols

1y, 1m, 1c, 1k Image carrier 2y, 2m, 2c, 2k Contact charging device 3y, 3m, 3c, 3k Developer 4ym, 4ck Primary transfer roll 5 Secondary transfer roll 6 Tertiary transfer roll Ly, Lm, Lc, Lk Laser beam 7 Transfer material 8 Scraper 9 BTR unit 10Y, 10M, 10C, 10Bk unit 11Y, 11M, 11C, 11Bk Photosensitive drum 12Y, 12M, 12C, 12Bk Corotron charger 13Y, 13M, 13C, 13Bk Exposure unit 14Y, 14M, 14C, 14Bk Developer 15Y, 15M, 15C, 15Bk Photoconductor cleaner 16 Intermediate transfer belt (intermediate transfer member)
17Y, 17M, 17C, 17Bk Transfer roller 20 Fixing roller (heat fixing roller)
21 Endless belt 22 Pressure pad (pressure member)
24 Halogen lamp 28 Oil impregnated member 30 Backup roller 31, 32, 33 Support roller 34 Belt cleaning device 35 Bias roller 36 Electrode roller P Recording sheet 10 Fixing roller 10a Metal core (cylindrical core)
10b Heat-resistant elastic layer 10c Release layer (heat-resistant resin layer)
11 Endless belt 12 Pressure pad (pressure member)
12a Pressure pad to which a strong nip pressure is applied 12b Pressure pad to which a weak nip pressure is applied 12c Metal holder 14 Halogen lamp 17 Toner 20 Peeling member 40 Lubricant supply member 41 Lubricant holding member 42 Lubricant permeation amount regulating film

Claims (3)

In an image forming method in which an electrostatic latent image on an electrophotographic photosensitive member is developed with a developer containing toner, and this is transferred to paper and fixed to obtain an image. An image forming method characterized by satisfying the above.
B) A peak exists between 11000 and 18000 and 500 to 2000 in the molecular weight distribution of the tetrahydrofuran elution of the toner. B) The volume average particle diameter of the toner is 4.4 to 5.8 μm.
C) There are 2 to 3 endothermic peaks at 50 to 73 ° C. when the temperature rises as measured by DSC of the toner, and the endothermic amount is 12.6 to 24.5 J / mg.
D) There are 1 to 3 exothermic peaks at 45 to 70 ° C during cooling as measured by DSC, and the half-value width of the maximum exothermic peak during cooling is greater than the half-value width of the endothermic maximum peak during temperature rise. Member is composed of polyimide belt In the molecular weight distribution of the toner tetrahydrofuran elution, there are peaks between 14000 and 17000 and 500 to 1000, the valley formed by these two peaks is at 1200 to 3000, and the elution starting molecular weight is 100,000 to 1,500,000. The image forming method according to claim 1, wherein: The average value of the circularity of the toner particles is 0.979 to 0.996, and there are 2 to 3 endothermic peaks at 50 to 71 ° C. at the time of temperature rise measured by DSC of the toner. The image forming method according to claim 1, wherein the image forming method is 4 to 24.5 J / mg.

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