JP2006234929A - Image forming method and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming method capable of preventing the occurrence of image unevenness based on the degradation in density at a leading end part liable to arise in a counter development system at a high process speed, preventing poor cleaning and toner filming, and preventing the occurrence of grazing as well, and capable of producing an electrophotographic image having good color reproducibility, and an image forming apparatus. <P>SOLUTION: The image forming apparatus comprises forming an electrostatic latent image on an organic photoreceptor of a cylindrical form at a process speed of ≥200 mm/sec and visualizing the electrostatic latent image to a toner image. The organic photoreceptor is ≥45.0 in the percentage ((We20/Wt20)x100) of an elastic deformation (We20) to a presser (total load 20 mN) of a specified weight applied from the surface of the photoreceptor and a total workload (wt20) and visualizes the electrostatic latent image to the toner image by rotating a developing sleeve with respect to the rotating direction of the rotating organic photoreceptor. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming method and an image forming apparatus used for electrophotographic image formation, and more particularly to an image forming method and an image forming apparatus used for electrophotographic image formation used in the field of copying machines and printers. Is.

  Electrophotographic photoconductors move from inorganic photoconductors such as Se, arsenic, arsenic / Se alloys, CdS, ZnO, etc. to organic photoconductors with excellent advantages such as pollution and ease of manufacture, and various materials are used. Organic photoreceptors (hereinafter also simply referred to as photoreceptors) have been developed.

  In recent years, function-separated type photoreceptors in which charge generation and charge transport functions are assigned to different materials have become mainstream, and for example, a photoreceptor containing polyarylate in the surface layer on a conductive support has been reported. (Patent Document 1).

  Turning to the electrophotographic process, latent image forming methods are roughly classified into analog image formation using a halogen lamp as a light source and digital image formation using an LED or laser as a light source. Recently, as a hard copy printer for a personal computer, and in an ordinary copying machine, a digital latent image forming method has been rapidly becoming mainstream because of the ease of image processing and the development of a multifunction device.

  In the digital image forming method, an opportunity to produce an original print image is increased, and a demand for high image quality is increasing. In order to improve the image quality of the electrophotographic image, a technique for forming a fine dot image on a toner image by forming a fine latent image on an organic photoreceptor using an exposure light source having a small spot diameter has been developed. .

  That is, as a developing method of the latent image on the organic photoreceptor, a developing method (hereinafter referred to as a parallel developing method) in which a developing sleeve provided on the organic photoreceptor is advanced in the developing region in parallel with the traveling direction of the organic photoreceptor. A developing method that advances in the counter direction (hereinafter referred to as a counter developing method) is known (Patent Document 2), but neither of them can sufficiently solve the problem in forming a high-density dot image.

  In the development system in which the developing sleeve provided on the organic photoreceptor is advanced in parallel with the traveling direction of the organic photoreceptor, the developability of the periphery of the high density image is deteriorated, the density tends to be insufficient, and the photograph has high contrast. The image quality is likely to deteriorate in an image or the like.

  On the other hand, the developing method that proceeds in the counter direction has high developability and can form a high-density dot image, but the traveling direction of the developing sleeve and the photosensitive member is opposite, so the surface of the organic photosensitive member is easily worn, A decrease in image density, in particular, a lack of density at the front end of the image, which is characteristic of counter development, tends to occur.

  In addition, the magnitude of the surface wear of the organic photoreceptor in the counter development method is greatly influenced by the process speed of image formation and the toner component used in the developer, and in particular, the process speed (the line of the active photoreceptor). The surface wear is likely to be large when the high speed is high (for example, 200 mm / sec or more) or when an external additive having a large particle size of 100 nm or more is used to prevent toner filming. Insufficient concentration at the tip is likely to occur, and due to unevenness of surface wear, cleaning failure is likely to occur.

  It has been found that the above-described phenomena are not sufficiently solved by merely improving the developer, and these phenomena are emphasized or improved by the characteristics of the organic photoreceptor.

  That is, it is presumed to be related to the surface physical properties of the organic photoreceptor and the production of reversely charged toner due to the friction between the organic photoreceptor and the developer.

That is, in the counter development method, reversely chargeable toner is likely to be generated due to contact friction between the photoconductor and the toner, and as a result, fogging and toner scattering are likely to occur, and the tip portion density is likely to be reduced. A fine electrostatic latent image cannot be reproduced as a toner image.
JP 11-38654 A JP 2001-125435 A

  The present invention solves the problems of the prior art as described above, that is, solves the problems easily caused by the counter development method at a high process speed, and stably forms a high-definition digital image. More specifically, it relates to a forming method, and more specifically, it prevents the occurrence of image unevenness due to a decrease in tip density, which is likely to occur in the counter development method at a high process speed, and prevents cleaning defects and toner filming. It is an object to provide an image forming method and an image forming apparatus capable of preventing the generation of scratches and producing an electrophotographic image with good color reproducibility.

  The above-described problem of the present invention, that is, the occurrence of image unevenness based on the decrease in the tip density, which is likely to occur in the counter development system at a high process speed, prevents defective cleaning and toner filming, In order to prevent the generation of scratches and to obtain an electrophotographic image with good color reproducibility, the relationship between the developer composition, the structure of the organic photoreceptor, and the development method was examined. By using a toner containing an inorganic external additive having a large particle size, the wear resistance of the organic photoconductor is prevented from being deteriorated by the counter method, and the surface of the organic photoconductor is always kept in place. By keeping it fresh, it is possible to prevent reverse chargeable toner that is likely to occur during development, and as a result, it is possible to prevent density defects at the leading edge of the image, as well as prevent cleaning defects and toner filming. And completed the present invention found that.

That is, the present invention is achieved by having the following configuration.
(Claim 1)
An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In the image forming method for visualizing an electrostatic latent image into a toner image, the organic photoconductor is subjected to an elastic deformation amount (We20) and a total work with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoconductor. The percentage of the amount (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and the electrostatic latent image is converted into a toner image by rotating the developing sleeve in the counter direction with respect to the rotating direction of the organic photoreceptor rotating. An image forming method characterized in that the image is visualized.
(Claim 2)
A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming method, each color toner image is formed on an organic photoreceptor using a toner whose color is changed, and the color toner image is transferred from the organic photoreceptor to a transfer medium to form a color image. However, the percentage of the elastic deformation (We20) and the total work (Wt20) with respect to a constant load indenter (total load is 20 mN) weighted from the surface of the photoreceptor ((We20 / Wt20) × 100) There are at 45.0 or more, with respect to the rotation direction of the organic photoreceptor which rotates the developing sleeve, an image forming method which comprises causing to rotate in the counter direction to the electrostatic latent image into a toner image.
(Claim 3)
An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In the image forming method for developing an electrostatic latent image into a toner image, the surface layer of the organic photoreceptor contains polyarylate, and the toner contains an inorganic external additive having a number average primary particle size of 100 to 1000 nm. And an electrostatic latent image is visualized as a toner image by rotating the developing sleeve in a counter direction with respect to the rotation direction of the organic photoreceptor rotating.
(Claim 4)
A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming method, each color toner image is formed on an organic photoreceptor using a toner whose color is changed, and the color toner image is transferred from the organic photoreceptor to a transfer medium to form a color image. The surface layer of the toner comprises polyarylate, the toner contains an inorganic external additive having a number average primary particle diameter of 100 to 1000 nm, and the rotating method of the organic photoreceptor rotating the developing sleeve To an image forming method which comprises causing to rotate in the counter direction to the electrostatic latent image into a toner image.
(Claim 5)
The image forming method according to claim 1, wherein the toner contains an inorganic external additive having a number average primary particle size of 100 to 1000 nm.
(Claim 6)
The image forming method according to claim 1, wherein the toner is a polymerized toner.
(Claim 7)
An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In the image forming apparatus that visualizes the electrostatic latent image into a toner image, the organic photoconductor is subjected to an elastic deformation amount (We20) and a total work with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoconductor. The percentage of the amount (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and the electrostatic latent image is converted into a toner image by rotating the developing sleeve in the counter direction with respect to the rotating direction of the organic photoreceptor rotating. An image forming apparatus characterized in that the image is visualized.
(Claim 8)
A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming apparatus for forming a color image by forming each color toner image on an organic photoconductor using a toner whose color is changed to the above, and transferring the color toner image from the organic photoconductor to a transfer medium, the organic photoconductor However, the percentage of the elastic deformation (We20) and the total work (Wt20) with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoreceptor ((We20 / Wt20) × 100) There are at 45.0 or more, with respect to the rotation direction of the organic photoreceptor which rotates the developing sleeve, an image forming apparatus for causing the electrostatic latent image is rotated in the counter direction is visualized into a toner image.

  By using the image forming method and the image forming apparatus of the present invention, it is possible to prevent the occurrence of image unevenness due to a decrease in the density of the tip portion, which is likely to occur in the counter development method at a high process speed, and to prevent defective cleaning and toner filming. Thus, the occurrence of scratches can be prevented, and an electrophotographic image having good color reproducibility can be provided.

Hereinafter, the present invention will be described in detail.
In the image forming method of the present invention, a process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is applied to the organic photosensitive member. An image forming method in which the electrostatic latent image is visualized as a toner image by bringing it into contact with a body, wherein the organic photoreceptor is applied to a constant-weight indenter (total load is 20 mN) applied from the surface of the photoreceptor. The percentage of elastic deformation (We20) and total work (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and it rotates in the counter direction with respect to the rotation direction of the organic photoreceptor rotating the developing sleeve. Thus, the electrostatic latent image is visualized into a toner image.

  In addition, the image forming method of the present invention forms an electrostatic latent image on a cylindrical organic photosensitive member with a process speed of 200 mm / sec or more, and an organic cylindrical developing sleeve carrying a developer containing toner. A plurality of image forming units having a developing unit that is arranged in contact with the photoconductor and visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photoconductor to a transfer medium are arranged. Forming a color toner image on the organic photoconductor using a toner whose color is changed for each of the plurality of image forming units, and transferring the color toner image from the organic photoconductor to a transfer medium to form a color image. Image forming method, wherein the organic photoreceptor is a percentage of the amount of elastic deformation (We20) and the total work (Wt20) with respect to a constant load indenter (total load is 20 mN) weighted from the surface of the photoreceptor ((W 20 / Wt20) × 100) is 45.0 or more, and the electrostatic latent image is visualized as a toner image by rotating in the counter direction with respect to the rotation direction of the organic photoreceptor rotating the developing sleeve. And

  Since the image forming method of the present invention has the above-described configuration, it prevents the occurrence of image unevenness due to a decrease in the density of the tip portion, which is likely to occur in the counter development method at a high process speed, thereby preventing cleaning failure and toner filming. Thus, it is possible to prevent the generation of scratches and provide an electrophotographic image with good color reproducibility.

  Hereinafter, the constitution of the organic photoreceptor according to the present invention will be described.

  The organophotoreceptor according to the present invention has a percentage ((We20 / Wt20)) of elastic deformation (We20) and total work (Wt20) with respect to a constant load indenter (total load is 20 mN) loaded from the surface of the photoreceptor. 100) is 45.0 or more.

  The measurement conditions for the elastic work (We20), viscous work (Wv20), and total work (Wt20) are described below.

Equipment used: Fischer scope H100V (microhardness measuring device) manufactured by Fischer Instruments Co., Ltd. Working indenter: Diamond Vickers indenter Load condition: Push in the Vickers indenter from the surface of the organic photoreceptor at a speed of 2.0 mN / sec. Time: 10 sec
Unloading condition: Remove the load at the same speed as the load Measurement sample Provide an intermediate layer, charge generation layer or charge transport layer, etc. of the same layer structure as the organophotoreceptor of the present invention on an aluminum plate, and prepare a sample prepared under the same conditions. Fix to H100V machine and push Vickers indenter perpendicular to the sample.

  The measurement is performed by the procedure of indenter load (10 sec) and unloading.

  An example of work function measurement data measured under the above conditions is illustrated in FIG.

  As the load on the horizontal axis in FIG. 6 increases, the amount of deformation on the vertical axis increases. When the load is stopped at point A and the accumulated load is gradually removed, the amount of deformation gradually decreases. The shaded portion (E region) is the elastic work, and the total of the shaded portion and the horizontal portion viscous work (V region) is the total work.

  In the present invention, as described above, the total work (Wt20) is the sum of the elastic work (We20) and the viscous work (Wv20) measured with an indentation load of 20 mN (total load is 20 mN).

  The organic photoreceptor of the present invention has a percentage of elastic deformation (We20) and total work (Wt20) ((We20 / Wt20) × 100) of 45.0 or more. When the percentage is less than 45.0, the wear deterioration of the organic photoreceptor is likely to be large, and particularly when used in combination with a toner containing a large particle size external additive, the wear deterioration is likely to be large in the counter development method. In addition, reversely chargeable toner is likely to occur, density defects at the front end of the image are likely to occur, and cleaning defects are likely to occur. In the organic photoreceptor containing mainly organic polymer or organic compound, the upper limit value is limited, and the experimental value hardly exceeds 60.0. Taking this into account, the practical range of the percentage is 45.0 or more and 60.0 or less.

  In order to fabricate an organic photoreceptor having a percentage of elastic deformation (We20) and total work (Wt20) of 45.0 or more according to the present invention, the surface layer is composed of a charge transport layer, and It is preferable to use arylate as a binder resin.

  Since the polyarylate resin has high rigidity of the resin itself, the polyarylate is used as a resin for the charge transport layer, and in combination with a charge transport material having a small decrease in the physical properties of the polyarylate resin in the charge transport layer, An organic photoreceptor having a percentage of elastic deformation (We20) and total work (Wt20) of 45.0 or more can be produced.

  As the polyarylate, the polyarylate of the following general formula (1) is preferably used.

(In the general formula (1), X ¹ is a carbon atom or a single bond (in the case of a single bond, R ⁵ and R ^{6 are} absent), R ^{1 to} R ⁴ are a hydrogen atom, a halogen atom, and an optionally substituted alkyl group. Or an aryl group which may be substituted, wherein R ⁵ and R ⁶ are a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted, or R ⁵ and R ⁶ are bonded to each other; And R ^{7 to} R ^{10 each} represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.
Although the specific example of the said General formula (1) is given to the following, in this invention, it is not restricted to these.

  Among these, Po-1, Po-2, Po-3, Po-10, Po-11, and Po-24 are preferable.

  The polyarylate resin used in the present invention may be a polymer composed of a single repeating structural unit or a copolymer composed of two or more kinds of repeating structural units.

  In the present invention, the viscosity average molecular weight of polyarylate is preferably 10,000 to 200,000, and more preferably 15,000 to 120,000.

  In the organophotoreceptor according to the present invention, it is preferable to use a charge transport material represented by the following general formula (2) together with the polyarylate resin in the charge transport layer forming the surface layer. The charge transport material has two or more hole transport sites in one molecule. For this reason, the charge transport material is contained in the polyarylate resin at a low molar concentration (even though the mass is the same, the number of moles is small). And decrease in physical properties of the polyarylate resin can be reduced.

[Wherein Ar ₅ , Ar ₆ and Ar ₇ represent a substituted or unsubstituted aromatic hydrocarbon or heterocyclic group, and R ₃ represents a hydrogen atom or a substituted or unsubstituted aromatic hydrocarbon group or heterocyclic group. Represents. n is 2 or 3. ]
Specific examples of the compound of the general formula (2) are listed below, but the present invention is not limited to the specific examples.

Among the general formula (2), Ar ₅ is preferably a phenyl group having a methyl group as a substituent, Ar ₆ is preferably an unsubstituted phenylene group, Ar ₇ is a substituted or unsubstituted phenyl group, R ₃ is preferably a phenyl group, particularly a phenyl group having a methyl group as a substituent.

  Moreover, among the compounds of the general formula (2), the compound having n = 2 is particularly excellent in compatibility with polyarylate, and the effects of the present invention can be achieved remarkably.

  In addition to the charge transport material of the above general formula (2), other charge transport materials (CTM) such as triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, and butadiene compounds are used in the charge transport layer. Can be used. In the combined use of these charge transport materials, the main charge transport material is preferably represented by the general formula (2).

  The mass ratio of the binder resin using the polyarylate in the charge transport layer and the charge transport material is preferably 30 to 200 parts by mass, more preferably 50 to 150 parts by mass with respect to 100 parts by mass of the binder.

  The charge transport layer preferably contains an antioxidant. Typical examples of the antioxidants prevent or suppress oxidation of auto-oxidizing substances existing in or on the surface of an organic photoreceptor under conditions such as light, heat, and discharge. It is a substance with the property to do.

  The thickness of the charge transport layer is preferably 10 to 40 μm. If the film thickness is less than 10 μm, deterioration of the halftone image tends to appear, and if it exceeds 40 μm, the residual power rises easily and sharpness tends to deteriorate.

  Further, the charge transport layer may be composed of two layers, and the polycarbonate of the present invention may be used for the charge transport layer serving as the surface layer.

  The antioxidant of the present invention is a substance having the property of preventing or suppressing the action of oxygen under conditions of light, heat, discharge, etc., against an auto-oxidizing substance present in the photoreceptor or on the photoreceptor surface. It is. Specifically, the following compound groups can be mentioned.

(1) Radical chain inhibitor ・ Phenol antioxidant (hindered phenol)
・ Amine antioxidants (hindered amines, diallyldiamines, diallylamines)
・ Hydroquinone antioxidant (2) Peroxide decomposer ・ Sulfur antioxidant (thioethers)
・ Phosphoric antioxidants (phosphites)
Among the above antioxidants, the radical chain inhibitor (1) is good, and a hindered phenol-based or hindered amine-based antioxidant is particularly preferable. Two or more types may be used in combination, for example, a combination of (1) a hindered phenol antioxidant and (2) a thioether antioxidant. Furthermore, the above-mentioned structural unit, for example, a hindered phenol structural unit and a hindered amine structural unit may be included in the molecule.

  Among the antioxidants, hindered phenol-based and hindered amine-based antioxidants are particularly effective in preventing fogging and image blurring at high temperatures and high humidity.

  The content of the hindered phenol-based or hindered amine-based antioxidant in the surface layer is preferably 0.01 to 20% by mass. When the content is less than 0.01% by mass, spots tend to occur. When the content exceeds 20% by mass, the charge transport ability in the surface layer decreases, the residual potential tends to increase, and the film strength decreases. Scratches are likely to occur.

  Here, hindered phenol refers to compounds having a branched alkyl group at the ortho position relative to the hydroxyl group of the phenol compound and derivatives thereof (however, the hydroxyl group may be converted to alkoxy).

  The hindered amine system is a compound having a bulky organic group near the N atom. The bulky organic group includes a branched alkyl group, for example, a t-butyl group is preferable. For example, compounds having an organic group represented by the following structural formula are preferred.

In the formula, R ₁₃ represents a hydrogen atom or a monovalent organic group, R ₁₄ , R ₁₅ , R ₁₆ and R ₁₇ represent an alkyl group, and R ₁₈ represents a hydrogen atom, a hydroxyl group or a monovalent organic group.

  Examples of the antioxidant having a hindered phenol partial structure include compounds described in JP-A-1-118137 (P7 to P14), but the present invention is not limited thereto.

  Examples of the antioxidant having a hindered amine partial structure include compounds described in JP-A-1-118138 (P7 to P9), but the present invention is not limited thereto.

  As an organic phosphorus compound, there exist the following as a typical thing with the compound represented by general formula: RO-P (OR) -OR, for example. Here, R represents a hydrogen atom, each substituted or unsubstituted alkyl group, alkenyl group or aryl group.

  As an organic sulfur type compound, there exist the following as a typical thing with the compound represented by general formula: R-S-R, for example. Here, R represents a hydrogen atom, each substituted or unsubstituted alkyl group, alkenyl group or aryl group.

  The following are examples of typical antioxidant compounds.

  Further, as the antioxidants that have been commercialized, the following compounds, for example, “Irganox 1076”, “Irganox 1010”, “Irganox 1098”, “Irganox 245”, “Irganox” as hindered phenols, are used. Knox 1330 "," Irganox 3114 "," Irganox 1076 "," 3,5-di-t-butyl-4-hydroxybiphenyl ", hindered amine series" Sanol LS2626 "," Sanol LS765 "," Sanol LS770 " , “Sanol LS744”, “Tinuvin 144”, “Tinuvin 622LD”, “Mark LA57”, “Mark LA67”, “Mark LA62”, “Mark LA68”, “Mark LA63”, and “Sumilyzer TPS” "," Sumi Iser TP-D ", and the phosphite system is" Mark 2112 "," Mark PEP-8 "," Mark PEP-24G "," Mark PEP-36 "," Mark 329K "," Mark HP-10 " Is mentioned.

  The present invention is an organic photoreceptor having the surface layer, and the constitution of the organic photoreceptor other than the surface layer will be described below.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor constituted by providing an organic compound with at least one of a charge generation function and a charge transport function essential to the configuration of the electrophotographic photoconductor. All known organic photoconductors such as a photoconductor composed of an organic charge generating material or an organic charge transport material, a photoconductor composed of a polymer complex with a charge generating function and a charge transport function are contained.

The configuration of the organophotoreceptor of the present invention is not particularly limited as long as the percentage of the elastic deformation (We20) and the total work (Wt20) is 45.0 or more. For example, as shown below Configuration may be mentioned;
1) A structure in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer on a conductive support. 2) A charge generation layer, a first charge transport layer and a second charge transport layer are formed as a photosensitive layer on a conductive support. Sequentially stacked configuration;
3) A structure in which a single layer containing a charge transport material and a charge generation material is formed as a photosensitive layer on a conductive support;
4) A structure in which a charge transport layer and a charge generation layer are sequentially laminated as a photosensitive layer on a conductive support;
5) A structure in which a surface protective layer is further formed on the photosensitive layer of the photoreceptors 1) to 5) above.

  The photoconductor may have any of the above configurations. The surface layer of the photoconductor of the present invention is a layer in which the photoconductor is in contact with the air interface. When only a single layer type photoconductive layer is formed on the conductive support, the photoconductive layer is a surface layer. In the case where a single-layer or laminated photosensitive layer and a surface protective layer are laminated on a conductive support, the surface protective layer is the outermost surface layer. In the present invention, the configuration 2) is most preferably used. Note that, regardless of the configuration of the photoreceptor of the present invention, an undercoat layer (intermediate layer) may be formed on the conductive support prior to the formation of the photosensitive layer.

  The charge transport layer means a layer having a function of transporting charge carriers generated in the charge generation layer by photoexposure to the surface of the organic photoreceptor, and the specific detection of the charge transport function is carried out between the charge generation layer and the charge transport layer. It can be confirmed by laminating a transport layer on a conductive support and detecting optical conductivity.

  Next, the layer structure of the organic photoreceptor preferably used in the present invention will be described with a focus on the structure of 1) above.

Conductive Support A cylindrical conductive support is used as the conductive support used for the photoreceptor.

  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 range of straightness and shake 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. The conductive support of the present invention is most preferably an aluminum support. As the aluminum support, one in which components such as manganese, zinc, magnesium and the like are mixed in addition to the main component aluminum is also used.

Intermediate layer In the present invention, an intermediate layer is preferably provided between the conductive support and the photosensitive layer.

  The intermediate layer used in the present invention preferably contains N-type semiconductor particles. The N-type semiconductive particle means a particle whose main charge carrier is an electron. That is, since the main charge carriers are electrons, the intermediate layer containing the N-type semiconductive particles in the insulating binder effectively blocks hole injection from the substrate, and the electrons from the photosensitive layer. In contrast, it has a property of low blocking.

  Here, a method for discriminating N-type semiconductor particles will be described.

  An intermediate layer having a thickness of 5 μm is formed on the conductive support (the intermediate layer is formed using a dispersion in which 50% by mass of particles are dispersed in the binder resin constituting the intermediate layer). The intermediate layer is negatively charged and the light attenuation characteristics are evaluated. In addition, the light attenuation characteristics are similarly evaluated by charging to positive polarity.

  N-type semiconductive particles are particles that are dispersed in the intermediate layer in the above evaluation when the light attenuation when charged negatively is greater than the light attenuation when charged positively. It is called semiconductive particle.

As the N-type semiconductor particles, titanium oxide (TiO ₂ ) and zinc oxide (ZnO) are preferable, and titanium oxide is particularly preferably used.

  As the N-type semiconductor particles, fine particles having a number average primary particle diameter in the range of 3.0 to 200 nm are used. Particularly, 5 nm to 100 nm is preferable. The number average primary particle diameter is a measured value as the average diameter in the ferret direction by image analysis by magnifying fine particles 10,000 times by transmission electron microscope observation, randomly observing 100 particles as primary particles. N-type semiconducting particles having a number average primary particle size of less than 3.0 nm are difficult to uniformly disperse in the intermediate layer binder and easily form agglomerated particles. Likely to happen. On the other hand, N-type semiconducting particles having a number average primary particle size larger than 200 nm tend to make large irregularities on the surface of the intermediate layer, and image irregularities are likely to occur through these large irregularities. Further, the N-type semiconducting particles having a number average primary particle size of greater than 200 nm are likely to precipitate in the dispersion and easily generate aggregates. As a result, image unevenness is likely to occur.

  The titanium oxide particles have anatase, rutile, brookite, and amorphous forms as crystal forms. Among them, the rutile form titanium oxide pigment or the anatase form titanium oxide pigment has a rectifying property of charge passing through the intermediate layer. That is, the electron mobility is increased, the charging potential is stabilized, the residual potential is prevented from increasing, and the generation of the transfer memory can be prevented. .

  N-type semiconductive particles are preferably surface-treated with a polymer containing methylhydrogensiloxane units. The molecular weight of the polymer containing the methyl hydrogen siloxane unit is 1000 to 20000, and the surface treatment effect is high. As a result, the rectifying property of the N-type semiconductor particles is improved, and the N-type semiconductor particles are contained. By using the intermediate layer, the occurrence of black spots is prevented and there is an effect in producing a good halftone image.

The polymer containing a methylhydrogensiloxane unit is preferably a copolymer of a structural unit of-(HSi (CH ₃ ) O)-and a structural unit other than this (other siloxane unit). As other siloxane units, dimethylsiloxane units, methylethylsiloxane units, methylphenylsiloxane units, diethylsiloxane units, and the like are preferable, and dimethylsiloxane is particularly preferable. The proportion of methylhydrogensiloxane units in the copolymer is 10 to 99 mol%, preferably 20 to 90 mol%.

  The methylhydrogensiloxane copolymer may be any of a random copolymer, a block copolymer, a graft copolymer, etc., but a random copolymer and a block copolymer are preferred. In addition to methylhydrogensiloxane, the copolymerization component may be one component or two or more components.

  Further, the N-type semiconductive particles may be those surface-treated with a reactive organosilicon compound represented by the following formula.

(R) _n -Si- (X) _4-n
(In the above formula, Si represents a silicon atom, R represents an organic group in which carbon is directly bonded to the silicon atom, X represents a hydrolyzable group, and n represents an integer of 0 to 3).
In the organosilicon compound represented by the above formula, the organic group in which carbon is directly bonded to the silicon represented by R includes alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and dodecyl, phenyl , Aryl groups such as tolyl, naphthyl and biphenyl, epoxy-containing groups such as γ-glycidoxypropyl and β- (3,4-epoxycyclohexyl) ethyl, γ-acryloxypropyl and γ-methacryloxypropyl ( (Meth) acryloyl group, hydroxyl group such as γ-hydroxypropyl, 2,3-dihydroxypropyloxypropyl, vinyl group such as vinyl and propenyl, mercapto group such as γ-mercaptopropyl, γ-aminopropyl, N-β Amino-containing groups such as (aminoethyl) -γ-aminopropyl, γ-chloropropyl, 1,1, - trifluoride Oro propyl, nonafluorohexyl, halogen-containing groups such as perfluorooctylethyl, other nitro, and cyano-substituted alkyl group. Examples of the hydrolyzable group for X include alkoxy groups such as methoxy and ethoxy, halogen groups, and acyloxy groups.

  Moreover, the organosilicon compound represented by the above formula may be used alone or in combination of two or more.

  Further, in the case of a specific compound of an organosilicon compound represented by the above formula and n is 2 or more, a plurality of R may be the same or different. Similarly, when n is 2 or less, the plurality of Xs may be the same or different. Moreover, when using 2 or more types of organosilicon compounds represented by the above formula, R and X may be the same or different between the respective compounds.

  Further, prior to the surface treatment of the methylhydrogensiloxane copolymer or the reactive organosilicon compound, the N-type semiconductive particles may be subjected to an inorganic surface treatment such as alumina or silica.

  In addition, although the above-mentioned treatment of alumina and silica may be performed simultaneously, it is preferable to perform the alumina treatment first and then the silica treatment. Further, the amount of treatment of alumina and silica when treating alumina and silica is preferably higher than that of alumina.

  The surface treatment of the N-type semiconductive fine particles such as titanium oxide with a metal oxide such as alumina, silica or zirconia can be performed by a wet method. For example, N-type semiconductive particles subjected to silica or alumina surface treatment can be prepared as follows.

  When titanium oxide particles are used as the N-type semiconductive particles, titanium oxide particles (number average primary particle size: 50 nm) are dispersed in water at a concentration of 50 to 350 g / L to form an aqueous slurry. Add acid salt or water-soluble aluminum compound. Thereafter, alkali or acid is added for neutralization, and silica or alumina is precipitated on the surface of the titanium oxide particles. Subsequently, filtration, washing, and drying are performed to obtain the target surface-treated titanium oxide. When sodium silicate is used as the water-soluble silicate, it can be neutralized with an acid such as sulfuric acid, nitric acid or hydrochloric acid. On the other hand, when aluminum sulfate is used as the water-soluble aluminum compound, it can be neutralized with an alkali such as sodium hydroxide or potassium hydroxide.

  The intermediate layer coating solution prepared for forming the intermediate layer used in the present invention is composed of a binder resin, a dispersion solvent and the like in addition to the N-type semiconductive particles such as the surface-treated titanium oxide.

  The ratio of the N-type semiconductive particles in the intermediate layer is preferably 1.0 to 2.0 times in terms of the volume ratio of the intermediate layer to the binder resin (when the volume of the binder resin is 1). By using the N-type semiconducting particles of the present invention at such a high density in the intermediate layer, the rectifying property of the intermediate layer is increased, and no increase in residual potential or transfer memory occurs even when the film thickness is increased. Therefore, it is possible to effectively prevent black spots and to form a good organic photoreceptor with a small potential fluctuation. Further, such an intermediate layer preferably uses 100 to 200 parts by volume of N-type semiconductive particles with respect to 100 parts by volume of the binder resin.

On the other hand, as the binder resin for dispersing these particles and forming the layer structure of the intermediate layer, a polyamide resin is preferable in order to obtain good dispersibility of the particles.
However, the polyamide resin shown below is particularly preferable.

  The binder resin for the intermediate layer is preferably an alcohol-soluble polyamide resin. As the binder resin for the intermediate layer of the organic photoreceptor, a resin having excellent solvent solubility is required in order to form the intermediate layer with a uniform film thickness. As such an alcohol-soluble polyamide resin, a copolymerized polyamide resin or a methoxymethylated polyamide resin having a chemical structure with few carbon chains between amide bonds such as 6-nylon described above is known.

  The following polyamide resins are also preferably used as the intermediate layer of the organic photoreceptor of the present invention.

  The molecular weight of the polyamide resin is preferably 5,000 to 80,000, more preferably 10,000 to 60,000 in terms of number average molecular weight. When the number average molecular weight is 5,000 or less, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. On the other hand, if it is larger than 80,000, the solvent solubility of the resin is liable to be reduced, and an agglomerated resin is likely to be generated in the intermediate layer, and image unevenness is likely to occur in black spots and halftone images.

  A part of the polyamide resin is already available on the market. For example, the polyamide resin is sold under the trade names such as Vestamelt X1010 and X4685 manufactured by Daicel Degussa Co., Ltd., and can be produced by a general synthesis method of polyamide. However, an example of a synthesis example is given below.

As the solvent for dissolving the polyamide resin and preparing the coating solution, alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are preferable, It is excellent in the solubility of polyamide and the coating property of the prepared coating solution. These solvents are 30 to 100% by mass, preferably 40 to 100% by mass, and more preferably 50 to 100% by mass in the total solvent. Examples of co-solvents that can be used in combination with the above-mentioned solvent to obtain preferable effects include methanol, benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.
The thickness of the intermediate layer of the present invention is preferably 0.3 to 10 μm. If the thickness of the intermediate layer is less than 0.5 μm, image unevenness is likely to occur in black spots and halftone images, and if it exceeds 10 μm, residual potential is increased and transfer memory is likely to occur, and sharpness is likely to deteriorate. As for the film thickness of an intermediate | middle layer, 0.5-5 micrometers is more preferable.

Moreover, it is preferable that the said intermediate | middle layer is an insulating layer substantially. Here, the insulating layer has a volume resistance of 1 × 10 ⁸ or more. The volume resistance of the intermediate layer and the protective layer of the present invention is preferably 1 × 10 ⁸ to 10 ¹⁵ Ω · cm, more preferably 1 × 10 ⁹ to 10 ¹⁴ Ω · cm, and further preferably 2 × 10 ⁹ to 1 ×. 10 ¹³ Ω · cm. The volume resistance can be measured as follows.

  Measurement conditions: According to JIS: C2318-1975.

Measuring instrument: Hiresta IP manufactured by Mitsubishi Yuka
Measurement conditions: Measurement probe HRS
Applied voltage: 500V
Measurement environment: 30 ± 2 ℃, 80 ± 5RH%
If the volume resistance is less than 1 × 10 ⁸ , the charge blocking property of the intermediate layer decreases, the occurrence of black spots increases, the potential holding property of the organic photoreceptor deteriorates, and good image quality cannot be obtained. On the other hand, if it is greater than 10 ¹⁵ Ω · cm, the residual potential tends to increase in repeated image formation, and good image quality cannot be obtained.

Photosensitive layer The photosensitive layer configuration of the photoreceptor of the present invention may be a single-layer photosensitive layer configuration in which the intermediate layer has a charge generation function and a charge transport function in one layer, but more preferably the function of the photosensitive layer. The charge generation layer (CGL) and the charge transport layer (CTL) may be separated from each other. 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 most preferred photosensitive layer structure of the present invention is a negatively charged photoreceptor structure having the function separation structure.

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

Charge generation layer The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives 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 which can minimize the increase in residual potential due to repeated use has a crystal structure capable of taking a stable aggregate structure among a plurality of molecules, specifically, a phthalocyanine pigment having a specific crystal structure, CGM of a perylene pigment is mentioned. For example, titanyl phthalocyanine having a maximum peak at a Bragg angle 2θ of 27.2 ° with respect to Cu—Kα rays, titanyl phthalocyanine having a remarkable diffraction peak at 7.5 ° and 28.7 ° of the same 2θ, and 12.2 of the same 2θ. CGM such as bisbenzimidazole perylene having a maximum peak at 4 is hardly deteriorated by repeated use, and the residual potential can be increased and decreased.

  When a binder is used as the CGM dispersion medium in the charge generation layer, a known resin can be used as the binder, but the most preferred resins include formal resin, butyral resin, silicone resin, silicone-modified butyral resin, phenoxy resin, and the like. Can be mentioned. The ratio of the binder resin to the charge generating material 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 μm to 1 μm. If the thickness is less than 0.01 μm, sufficient sensitivity characteristics cannot be obtained, and the residual potential tends to increase. On the other hand, even if the thickness exceeds 1 μm, the sensitivity tends to decrease and a transfer memory tends to occur.

Charge Transport Layer The charge transport layer of the present invention is used as the charge transport layer of the present invention.

  The total thickness of the charge transport layer is preferably 10 to 40 μm. If the total film thickness is less than 10 μm, image unevenness is likely to occur, and if it exceeds 40 μm, the residual power is likely to increase, and the sharpness tends to deteriorate. Further, the thickness of the charge transport layer serving as the surface layer is preferably 0.5 to 10 μm.

  Solvents or dispersion media used to form layers such as intermediate layers, charge generation layers, and charge transport layers include n-butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine, triethylenediamine, N, N-dimethylformamide, acetone , Methyl ethyl ketone, methyl isopropyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, dichloromethane, 1,2-dichloroethane, 1,2-dichloropropane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, trichloroethylene, Tetrachloroethane, tetrahydrofuran, dioxolane, dioxane, methanol, ethanol, butanol, isopropanol, ethyl acetate, butyl acetate, dimethyl sulfoxide, methyl cello Lube, and the like. Although this invention is not limited to these, Dichloromethane, 1, 2- dichloroethane, methyl ethyl ketone, etc. are used preferably. These solvents may be used alone or as a mixed solvent of two or more.

  Further, the coating solution for each layer is preferably filtered with a metal filter, a membrane filter or the like in order to remove foreign matters and aggregates in the coating solution before entering the coating step. For example, it is preferable to select a pleat type (HDC), a depth type (profile), a semi-depth type (profile star), etc., manufactured by Nippon Pole Co., Ltd. according to the characteristics of the coating solution and perform filtration.

  Next, as a coating processing method for producing the organic photoreceptor, a coating processing method such as dip coating or spray coating is used in addition to the slide hopper type coating device. The surface layer is most preferably the circular slide hopper type coating device.

Next, the toner of the present invention will be described.
The toner of the present invention preferably contains, as colored additives, inorganic particles having at least a number average primary particle size of 100 to 1000 nm as external additives (containing inorganic particle external additives).

  That is, in the present invention, a developer containing toner having an external additive of inorganic particles having a number average primary particle size of 100 to 1000 nm as described above is used for the photoreceptor having the charge transport layer (surface layer). In addition, toner filming is prevented, and as a result, generation of a chargeable toner that is likely to occur during development can be prevented to prevent a decrease in density at the tip portion, and a good electrophotographic image can be obtained. In particular, a counter development system at a high process speed is achieved by using a toner having the above-described external additive and a photoreceptor having a percentage of the elastic deformation (We20) and the total work (Wt20) of 45.0 or more. Prevents the occurrence of image unevenness due to the lowering of the tip density, which is likely to occur, prevents poor cleaning and toner filming, prevents scratches, and obtains an electrophotographic image with good color reproducibility. Can do.

  The external additive of the present invention means an additive or the like for modifying the surface of a toner to be added after a toner (prototype of toner) is prepared by a polymerization method or a pulverization method.

  The toner of the present invention is a toner prepared by adding inorganic particles having a number average primary particle size of 100 to 1000 nm to colored particles (prototype of toner). If the thickness is less than 100 nm, the toner is in contact with the photosensitive member and has a small buffering effect on the toner and the photosensitive member such as a pressing cleaning blade, the effect of preventing filming and the like is small, and white spots are likely to occur. On the other hand, when the thickness is larger than 1000 nm, the inorganic external additive is released from the toner and adheres to the tip of the cleaning blade, and the cleaning blade is worn out, so that defective cleaning such as toner slippage tends to occur. Further, the liberated external additive causes contamination of the band electrode and the transfer electrode, which causes image defects such as white stripes.

Of these, titanium oxide, silica, strontium titanate, barium titanate, calcium titanate, cerium oxide and the like can be preferably used as materials for inorganic particles of 100 to 1000 nm. Among them, as the inorganic particles, those having a small specific surface area are more effective for preventing filming, and those having a BET value of 20 m ² / g or less are preferable. In addition, it is more preferred that the surface be hydrophobized.

  The addition amount is preferably 0.1 to 3.0% by mass in the toner (here, the total mass of the toner indicates the total mass including inorganic particles), more preferably 0.5 to 2.0. % By mass. If this range is exceeded, the cleaning effect will increase, but there will be a problem that the large-sized inorganic particles themselves will be liberated, and the scattered particles will cause contamination of the band electrode and the transfer electrode, such as white streaks. Cause image defects. Moreover, when too small, the effect with respect to a white spot cannot be exhibited.

  Furthermore, it is preferable to add inorganic particles of 5 to 49 nm. Those preferably used as these materials are silica, alumina, titania, zirconia and the like.

  The inorganic particles of 5 to 49 nm are also preferably added to the toner in an amount of 0.1 to 3.0% by mass, and more preferably 0.3 to 2.5% by mass. If added beyond this range, the cleaning property itself is improved, but there is a problem that the inorganic particles themselves are liberated, and the scattered particles cause contamination of the band electrode and the transfer electrode, and images such as white stripes. Causes defects. Further, since the inorganic particles are present in the toner in a free state, it causes a scratch on the photoreceptor, and the photoreceptor is scratched, so-called black spots and white spots are induced. If the amount is too small, the cleaning effect cannot be exhibited.

  The above particle diameter is a number average primary particle diameter, which is magnified 2000 times by observation with a transmission electron microscope, observed 100 particles, and measured by image analysis.

  Moreover, what hydrophobized the said inorganic inorganic particle may be used. In the case of performing the hydrophobizing treatment, it is preferable to hydrophobize with a so-called coupling agent such as various titanium coupling agents and silane coupling agents, or silicone oil, and further, aluminum stearate, zinc stearate, calcium stearate. Hydrophobic treatment with a higher fatty acid metal salt such as is also preferably used.

In addition to the inorganic particle external additive, a lubricant may be added to the toner of the present invention. For example, zinc stearate, aluminum, copper, magnesium, calcium salt, zinc oleate, manganese, iron, copper, magnesium salt, zinc palmitate, copper, magnesium, calcium salt, linoleic acid Examples thereof include metal salts of higher fatty acids such as zinc and calcium salts, and zinc and calcium ricinoleic acid salts. The addition amount of these lubricants is preferably about 0.1 to 5% by mass with respect to the toner.
[Tonerization process]
As a method for adding the external additive, various known mixing apparatuses such as a Turbuler mixer, a Henschel mixer, a Nauter mixer, and a V-type mixer can be used.

  In addition to the colorant and the release agent, the toner may be added with a material that can provide various functions as a toner material. Specific examples include charge control agents. These components can be added in the production stage of the colored particles at the stage of the toner (also referred to as colored particles) before adding the external additive. The colored particles may be prepared by a conventional pulverization method or a polymerization method.

  When producing colored particles by a pulverization method, a release agent and a charge control agent can be added at the kneading stage of the resin and the pigment. On the other hand, in the case of producing by a polymerization method, a method of adding at the stage of resin polymerization, a method of adding simultaneously with a pigment or the like at the stage of resin particle aggregation after the production of resin particles, and the like can be mentioned.

  In addition, as a mold release agent in the polymerization method, it is preferable to use various known ones that can be dispersed in water. Specific examples include olefinic waxes such as polypropylene and polyethylene, modified products thereof, natural waxes such as carnauba wax and rice wax, and amide waxes such as fatty acid bisamides. It has already been mentioned that these are added as release agent particles and are preferably salted out / fused together with resin and colorant.

  Similarly, various known charge control agents in the polymerization method and those that can be dispersed in water can be used. Specific examples 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.

  These release agent and charge control agent particles preferably have a number average primary particle size of about 10 to 500 nm in a dispersed state.

  Hereinafter, the toner (colored particles) by the polymerization method preferably used in the present invention will be described.

  As the toner applied to the present invention, a polymerized toner having a relatively uniform particle size distribution and shape of individual toner particles is preferable. Here, the polymerized toner means a toner obtained by forming a binder resin for toner and forming the toner shape by polymerization of a raw material monomer of the binder resin and subsequent chemical treatment. More specifically, it means a toner obtained through a polymerization reaction such as suspension polymerization or emulsion polymerization and, if necessary, a fusing step between particles carried out after the polymerization reaction.

  The polymerized toner used in the present invention is preferably a toner having a specific shape. The polymerized toner that can be preferably used in the present invention will be described below.

  As a preferred polymerized toner applied to the present invention, a toner having 65% by number or more of toner particles having a shape factor in the range of 1.2 to 1.6 and a coefficient of variation of the shape factor of 16% or less is used. It is to be. It has been found that when a polymerized toner having such characteristics is used, the vibration of the cleaning blade can be stabilized and excellent cleaning performance can be exhibited.

  Also, the vibration stability of the cleaning blade varies depending on the particle size of the toner particles. The smaller the particle size, the higher the adhesion force to the image carrier, so that the vibration is likely to be excessive and the toner is contained in the cleaning blade. There is a high probability of passing through. However, when the toner particle diameter is large, such slip-through is reduced, but there is a problem that image quality such as resolution is lowered.

  As a result of studying from the above viewpoint, the toner having a variation coefficient of the toner shape factor of 16% or less and a toner having a number variation coefficient of 27% or less in the number particle size distribution of the toner, It has been found that high-quality image quality can be formed over a long period of time with excellent fine line reproducibility.

  In addition, by using toner particles with no corners at 50% by number or more and controlling the number variation coefficient in the number particle size distribution to 27% or less, excellent cleaning properties and fine line reproducibility, and high quality image quality for a long time Can be formed over.

  The shape factor of the toner is expressed by the following formula and indicates the degree of roundness of the toner particles.

Shape factor = ((maximum diameter / 2) ² × π) / projection area Here, the maximum diameter is the distance between the parallel lines when the projected image of toner particles on a plane is sandwiched between two parallel lines. The maximum particle width. The projected area refers to the area of the projected image of the toner particles on the plane.

  This shape factor is obtained by taking a photograph in which toner particles are magnified 2000 times with a scanning electron microscope, and then analyzing a photographic image using “SCANNING IMAGE ANALYZER” (manufactured by JEOL Ltd.) based on this photograph. Was measured. At this time, the shape factor of the present invention was measured by the above formula using 100 toner particles.

  As the polymerized toner, the number of toner particles having a shape factor in the range of 1.2 to 1.6 is preferably 65% by number or more, and more preferably 70% by number or more.

  When the number of toner particles having a shape factor in the range of 1.2 to 1.6 is 65% by number or more, the triboelectric chargeability on the developer conveying member and the like becomes more uniform, and excessively charged toner is accumulated. In addition, since it becomes easier to replace the toner from the surface of the developer conveying member, problems such as development ghost are less likely to occur. Further, the toner particles are less likely to be crushed, the contamination of the charging member is reduced, and the chargeability of the toner is stabilized.

  The method for controlling the shape factor is not particularly limited. For example, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy due to impact force in a gas phase, or a method in which a toner is not dissolved in a solvent and a swirl flow is applied. Thus, there is a method in which a toner having a shape factor of 1.2 to 1.6 is prepared and added to a normal toner so as to be within the range of the present invention. In addition, the overall shape is controlled at the stage of adjusting the so-called polymerization method toner, and the toner whose shape factor is adjusted to 1.0 to 1.6 or 1.2 to 1.6 is similarly added to the normal toner. There is a way to adjust.

  The variation coefficient of the shape factor of the polymerized toner is calculated from the following equation.

Coefficient of variation = [S / K] x 100 (%)
[In the formula, S represents the standard deviation of the shape factor of 100 toner particles, and K represents the average value of the shape factor. ]
The variation coefficient of the shape factor is preferably 16% or less, and more preferably 14% or less. When the variation coefficient of the shape factor is 16% or less, voids in the transferred toner layer are reduced, fixing property is improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp and the image quality is improved.

  Toner particles that are being formed in the process of polymerizing, fusing, and controlling the shape of resin particles (polymer particles) in order to uniformly control the shape factor of the toner and the coefficient of variation of the shape factor without variation in lots. An appropriate process end time may be determined while monitoring the characteristics of the (colored particles).

  Monitoring means that a measuring device is incorporated in-line, and process conditions are controlled based on the measurement result. In other words, in the case of a polymerization method toner that is formed by incorporating measurement such as shape in-line, for example, by associating or fusing resin particles in an aqueous medium, the shape and particle size are measured while performing sequential sampling in the fusing step. The reaction is stopped when the desired shape is obtained.

  Although it does not specifically limit as a monitoring method, The flow type particle image analyzer FPIA-2000 (made by Toa Medical Electronics Co., Ltd.) can be used. This apparatus is suitable because the shape can be monitored by performing image processing in real time while passing the sample liquid. That is, a pump or the like is used from the reaction field and is constantly monitored to measure the shape and the like, and the reaction is stopped when the desired shape is obtained.

  The number particle size distribution and the number variation coefficient of the toner are measured by a Coulter Counter TA-II or Coulter Multisizer (manufactured by Coulter Inc.). In the present invention, a Coulter Multisizer is used, and an interface (manufactured by Nikkaki Co., Ltd.) that outputs a particle size distribution and a personal computer are connected. The aperture used in the Coulter Multisizer was 100 μm, and the volume and number of toners of 2 μm or more were measured to calculate the particle size distribution and average particle size. The number particle size distribution represents the relative frequency of the toner particles with respect to the particle size, and the number average particle size represents the median diameter in the number particle size distribution.

  The number variation coefficient in the toner number particle size distribution is calculated from the following equation.

Number variation coefficient = [S / Dn] × 100 (%)
[In the formula, S represents the standard deviation in the number particle size distribution, and Dn represents the number average particle size (μm). ]
The number variation coefficient of the toner is preferably 27% or less, and more preferably 25% or less. When the number variation coefficient is 27% or less, voids in the transferred toner layer are reduced, fixing properties are improved, and offset is less likely to occur. In addition, the charge amount distribution becomes sharp, the transfer efficiency is increased, and the image quality is improved.

  The method for controlling the number variation coefficient is not particularly limited. For example, a method of classifying toner particles by wind force can be used, but classification in a liquid is effective for reducing the number variation coefficient. As a method of classifying in this liquid, there is a method of separating and collecting toner particles according to a difference in sedimentation speed caused by a difference in toner particle diameter by using a centrifuge and controlling the rotation speed.

  In particular, when a toner is produced by a suspension polymerization method, a classification operation is indispensable in order to make the number variation coefficient in the number particle size distribution 27% or less. In the suspension polymerization method, it is necessary to disperse a polymerizable monomer in an oil droplet having a desired size as a toner in an aqueous medium before polymerization. That is, mechanical shearing with a homomixer or homogenizer is repeated for large oil droplets of a polymerizable monomer to reduce the oil droplets to the size of toner particles. In the method using shearing, the number particle size distribution of the obtained oil droplets is wide, and therefore the particle size distribution of the toner obtained by polymerizing the oil droplets is also wide. For this reason, classification operation is essential.

  The toner particles having no corners are toner particles that do not substantially have a protrusion that concentrates charges or a protrusion that easily wears due to stress. That is, as shown in FIG. When the major axis of the particle T is L, a circle C having a radius (L / 10) is rolled into the toner T when the inner side is rolled in contact with the peripheral line of the toner particle T at one point. The case where the toner particles do not substantially protrude outside is referred to as “toner particles having no corners”. “A case where the protrusion does not substantially protrude” refers to a case where the protrusion having the protruding circle is one or less. The “major diameter of toner particles” refers to the width of a particle that maximizes the interval between the parallel lines when the projected image of the toner particles on a plane is sandwiched between two parallel lines. FIGS. 1B and 1C show projected images of toner particles having corners, respectively.

  The measurement of toner without corners was performed as follows. First, an enlarged photograph of the toner particles is taken with a scanning electron microscope, and further enlarged to obtain a 15,000 times photographic image. The photographic image is then measured for the presence or absence of the corners. This measurement was performed on 100 toner particles.

  The proportion of toner particles having no corners is preferably 50% by number or more, and more preferably 70% by number or more. When the ratio of toner particles having no corners is 50% by number or more, generation of fine particles is less likely to occur due to stress with the developer conveying member, and the toner having excessive adhesion to the surface of the developer conveying member. In addition, the contamination of the developer conveying member can be suppressed, and the charge amount can be sharpened. In addition, toner particles that easily wear and break and toner particles having a portion where charges are concentrated are reduced, the charge amount distribution becomes sharp, the chargeability is stable, and good image quality can be formed over a long period of time.

  A method for obtaining toner having no corners is not particularly limited. For example, as described above as a method for controlling the shape factor, a method in which toner particles are sprayed into a hot air stream, a method in which toner particles are repeatedly applied with mechanical energy by impact force in a gas phase, or a toner is dissolved. It can be obtained by adding in a solvent that does not, and applying a swirling flow.

  Further, in the polymerization toner formed by associating or fusing the resin particles, the fusing particle surface has many irregularities at the fusing stop stage, and the surface is not smooth, but the temperature in the shape control step, By making the conditions such as the number of revolutions of the stirring blade and the stirring time appropriate, a toner having no corners can be obtained. These conditions vary depending on the physical properties of the resin particles. For example, by setting the rotational speed to be higher than the glass transition temperature of the resin particles, the toner can be formed with a smooth surface and no corners.

  The toner of the present invention preferably has a number average particle diameter of 3 to 8 μm. When the toner particles are formed by a polymerization method, the particle size can be controlled by the concentration of the aggregating agent, the amount of the organic solvent added, the fusing time, and further the composition of the polymer itself.

  When the number average particle diameter is 3 to 8 μm, it is possible to reduce the presence of excessively adhering toner or low adhering toner on the developer conveying member in the fixing step, and developability over a long period of time. And the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.

As the polymerized toner preferably used in the present invention, when the particle diameter of the toner particle is D (μm), the natural logarithm lnD is taken on the horizontal axis, and the horizontal axis is divided into a plurality of classes at intervals of 0.23. In the histogram showing the particle size distribution, the relative frequency (m ₁ ) of the toner particles included in the most frequent class and the relative frequency (m ₂ ) of the toner particles included in the most frequent class after the most frequent class. A toner having a sum (M) of 70% or more is preferable.

When the sum (M) of the relative frequency (m ₁ ) and the relative frequency (m ₂ ) is 70% or more, the dispersion of the particle size distribution of the toner particles is narrowed, so that the toner is used in the image forming process. The occurrence of selective development can be reliably suppressed.

  In the present invention, the histogram showing the particle size distribution based on the number is a natural logarithm lnD (D: particle size of individual toner particles) having a plurality of classes (0 to 0.23: 0.23) at intervals of 0.23. 0.46: 0.46-0.69: 0.69-0.92: 0.92-1.15: 1.15-1.38: 1.38-1.61: 1.61-1. 84: 1.84 to 2.07: 2.07 to 2.30: 2.30 to 2.53: 2.53 to 2.76, and so on). This histogram is prepared by transferring the particle size data of a sample measured by a Coulter Multisizer to a computer via an I / O unit according to the following conditions and using the particle size distribution analysis program in the computer. is there.

〔Measurement condition〕
(1) Aperture: 100 μm
(2) Sample preparation method: Electrolyte [ISOTON R-11 (manufactured by Coulter Scientific Japan)] 50-100 ml, an appropriate amount of a surfactant (neutral detergent) was added and stirred, and a measurement sample 10-20 mg was added thereto. Add This system is prepared by dispersing for 1 minute with an ultrasonic disperser.

  Among the methods for controlling the shape factor, the polymerization toner is preferable because it is simple as a production method and has excellent surface uniformity as compared with the pulverized toner.

  The polymerized toner is produced by emulsion polymerization of monomers in a suspension polymerization method or in a solution to which an emulsion of necessary additives is added to produce fine polymer particles, and then an organic solvent, an aggregating agent, etc. It can manufacture by the method of adding and associating. A method of preparing by mixing with a dispersion liquid such as a release agent or a colorant necessary for the composition of the toner at the time of association, or a toner component such as a release agent or a colorant is dispersed in the monomer And a method of emulsion polymerization. Here, the association means that a plurality of resin particles and colorant particles are fused.

  That is, various constituent materials such as a colorant and, if necessary, a release agent, a charge control agent, and a polymerization initiator are added to the polymerizable monomer, and a homogenizer, a sand mill, a sand grinder, an ultrasonic disperser, etc. Various constituent materials are dissolved or dispersed in the polymerizable monomer. The polymerizable monomer in which these various constituent materials are dissolved or dispersed is dispersed in oil droplets having a desired size as a toner in an aqueous medium containing a dispersion stabilizer using a homomixer or a homogenizer. Thereafter, the stirring mechanism is transferred to a reaction apparatus which is a stirring blade described later, and the polymerization reaction is advanced by heating. After completion of the reaction, the dispersion stabilizer is removed, filtered, washed, and dried to prepare a toner.

  Further, as a method for producing the toner of the present invention, a method of preparing by associating or fusing resin particles in an aqueous medium can also be mentioned. The method is not particularly limited, and examples thereof include methods disclosed in JP-A-5-265252, JP-A-6-329947, and JP-A-9-15904. That is, a method of associating a plurality of fine particles composed of resin particles and colorants, etc., or particles composed of resin and colorant, in particular, after dispersing them in water using an emulsifier, the critical aggregation concentration The above flocculant is added for salting out, and at the same time, the formed polymer itself is heated and fused at a temperature higher than the glass transition temperature to gradually grow the particle size while forming fused particles. Then, a large amount of water is added to stop the particle size growth, and the shape is controlled by smoothing the particle surface while heating and stirring, and the particles are heated and dried in a fluidized state while containing water, whereby toner Can be formed. Here, an organic solvent that is infinitely soluble in water may be added simultaneously with the flocculant.

  In addition, the aqueous medium as used in the field of this invention shows what contained 50 mass% or more of water at least.

  As the polymerizable monomer constituting the resin, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decyl Styrene, styrene or styrene derivatives such as pn-dodecylstyrene, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Methacrylic acid ester derivatives such as lauryl tacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylic Acrylates such as isobutyl acid, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, olefins such as ethylene, propylene, isobutylene, vinyl chloride, vinylidene chloride, Halogenated vinyls such as vinyl bromide, vinyl fluoride, vinylidene fluoride, vinyl esters such as vinyl propionate, vinyl acetate, vinyl benzoate, vinyl methyl ether, vinyl ethyl ether Vinyl ethers such as tellurium, vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, vinyl hexyl ketone, N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, vinyl naphthalene, vinyl pyridine, etc. There are acrylic acid or methacrylic acid derivatives such as vinyl compounds, acrylonitrile, methacrylonitrile, acrylamide and the like. These vinyl monomers can be used alone or in combination.

  Further, it is more preferable to use a combination of monomers having an ionic dissociation group as the polymerizable monomer constituting the resin. For example, it has a substituent such as a carboxyl group, a sulfonic acid group, a phosphoric acid group as a constituent group of the monomer, specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumar Acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropane sulfonic acid, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxy And propyl methacrylate.

  Furthermore, polyfunctionality such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, etc. It is also possible to use a crosslinkable resin by using a functional vinyl.

  These polymerizable monomers can be polymerized using a radical polymerization initiator. In this case, an oil-soluble polymerization initiator can be used in the suspension polymerization method. Examples of the oil-soluble polymerization initiator include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carboxyl). Nitriles), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azo- or diazo-based polymerization initiators such as azobisisobutyronitrile, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4- t-butylperoxycyclohexyl) propane, tris The (t-butylperoxy) triazine peroxide polymerization initiator or a peroxide, such as and the like polymeric initiator having a side chain.

  Moreover, when using an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, hydrogen peroxide and the like.

  Dispersion stabilizers include tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate , Bentonite, silica, alumina and the like. Furthermore, those generally used as surfactants such as polyvinyl alcohol, gelatin, methylcellulose, sodium dodecylbenzenesulfonate, ethylene oxide adduct, and higher alcohol sodium sulfate can be used as the dispersion stabilizer.

  As the resin excellent in the present invention, those having a glass transition point of 20 to 90 ° C. are preferred, and those having a softening point of 80 to 220 ° C. are preferred. The glass transition point is measured by a differential calorimetric analysis method, and the softening point can be measured by a Koka flow tester. Furthermore, these resins preferably have a molecular weight measured by gel permeation chromatography of 1,000 to 100,000 in terms of number average molecular weight (Mn) and 2000 to 1,000,000 in terms of weight average molecular weight (Mw). Further, the molecular weight distribution is preferably such that Mw / Mn is 1.5 to 100, particularly 1.8 to 70.

  The flocculant used is not particularly limited, but those selected from metal salts are preferably used. Specifically, as a monovalent metal, for example, an alkali metal salt such as sodium, potassium or lithium, as a divalent metal, for example, an alkaline earth metal salt such as calcium or magnesium, or a divalent metal such as manganese or copper. And salts of trivalent metals such as iron and aluminum, and specific salts include sodium chloride, potassium chloride, lithium chloride, calcium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc. Can be mentioned. These may be used in combination.

  These flocculants are preferably added in an amount equal to or higher than the critical aggregation concentration. The critical flocculation concentration is an index relating to the stability of the aqueous dispersion, and indicates a concentration at which flocculation occurs when a flocculant is added. This critical aggregation concentration varies greatly depending on the emulsified components and the dispersant itself. For example, it is described in Seizo Okamura et al., “Polymer Chemistry 17, 601 (1960) edited by Polymer Society” and the like, and a detailed critical aggregation concentration can be obtained. As another method, a desired salt is added to the target particle dispersion at different concentrations, the ζ (zeta) potential of the dispersion is measured, and the salt concentration at which this value changes is defined as the critical aggregation concentration. You can ask for it.

  The addition amount of the flocculant may be not less than the critical aggregation concentration, but is preferably 1.2 times or more, more preferably 1.5 times or more of the critical aggregation concentration.

  The solvent that dissolves infinitely means a solvent that dissolves infinitely in water, and in the present invention, a solvent that does not dissolve the formed resin is selected. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, t-butanol, methoxyethanol, and butoxyethanol, nitriles such as acetonitrile, and ethers such as dioxane. In particular, ethanol, propanol, and isopropanol are preferable.

  The addition amount of the infinitely soluble solvent is preferably 1 to 100% by volume with respect to the polymer-containing dispersion to which the flocculant is added.

  In order to make the shape uniform, it is preferable to fluidly dry a slurry in which 10% by mass or more of water is present after preparing and filtering colored particles. Those having a polar group are preferred. The reason for this is considered to be that it is particularly easy to make the shape uniform in order to exhibit the effect that the water present is somewhat swollen with respect to the polymer in which the polar group is present.

  The toner of the present invention contains at least a resin and a colorant, but may contain a release agent, a charge control agent, or the like, which is a fixability improving agent, if necessary. Further, an external additive composed of inorganic particles, organic fine particles, or the like may be added to the toner particles mainly composed of the resin and the colorant.

  As the colorant used in the toner, carbon black, magnetic material, dye, pigment and the like can be arbitrarily used. As the carbon black, channel black, furnace black, acetylene black, thermal black, lamp black and the like are used. . Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum, manganese-copper-tin, chromium dioxide, or the like can be used.

  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 etc. can be used, and a mixture thereof can also be used. Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment yellow 14, 17, 93, 94, 138, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 60, etc. can be used, and a mixture thereof can also be used. The number average primary particle diameter varies depending on the type, but is preferably about 10 to 200 nm.

  As a method for adding the colorant, the polymer particles prepared by the emulsion polymerization method are added at the stage of agglomerating by adding an aggregating agent, and the polymer is colored, or at the stage of polymerizing the monomer. The method of adding, polymerizing, and making it a colored particle etc. can be used. In addition, when adding a coloring agent in the step which prepares a polymer, it is preferable to use it, treating the surface with a coupling agent etc. so that radical polymerization property may not be inhibited.

  Further, a low molecular weight polypropylene (number average molecular weight = 1500 to 9000), a low molecular weight polyethylene, or the like as a fixing property improving agent may be added.

  Similarly, various known charge control agents and those that can be dispersed in water can be used. Specific examples 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.

  In addition, it is preferable that the number average primary particle diameter of these charge control agent and fixability improving agent particles is about 10 to 500 nm in a dispersed state.

  A developing device of the counter direction developing system will be described with reference to FIG. In the developing device 102, a developing sleeve 120 in which a cylindrical magnet 121 is disposed in a non-rotating manner is disposed in an opening portion of a developing container 110 containing a two-component developer so as to face the organic photoreceptor 101. 120 rotates in the counter direction with respect to the organic photosensitive member 101 rotating in the direction of the arrow, and conveys the developer adsorbed and held on the surface to the developing unit facing the organic photosensitive member 101. The magnet 121 has a developing magnetic pole N1 on the organic photoreceptor 101 side, and the first conveying magnetic pole S3, the second conveying magnetic pole N2, the third conveying magnetic pole S2, and the second conveying magnetic pole S2 are arranged in the rotational direction of the developing sleeve 120 from the developing magnetic pole N1. 3. It has a pumping magnetic pole S1 constituting a conveying magnetic pole and a separating magnetic pole.

  The developer in the developing container 110 is attracted and held on the developing sleeve 120 by the action of the pumping magnetic pole S1 at the position (pumping position) Q1 on the surface of the developing sleeve 120 corresponding to the pumping magnetic pole S1 of the magnet 121, and the developing blade After the layer thickness is regulated by 122, the developing unit is reached, and a magnetic brush is formed by the action of the developing magnetic pole N 1 in the developing unit to develop the latent image on the organic photoreceptor 101.

  The developer whose toner density is reduced by the development is held on the developing sleeve 120 and returned to the inside of the developing container 110 by the action of the first and second transport magnetic poles S3 and N2, and the third transport magnetic pole S2 and the pumping magnetic pole S1. At the position (developer dropping position) P1 on the surface of the developing sleeve 120 where the magnetic flux density is the smallest. As described above, the developer sleeve 120 from which the developer has been peeled is adsorbed and held at the pumping position Q1.

  A first agitating and conveying member 123 is installed below the developing sleeve 120 in the developing container 110, and a second agitating and conveying member 124 is further installed via a partition wall 140. These first and second agitating / conveying members 123 and 124 are of a screw type and have a helical screw blade 128 and a plate-like protrusion 130 between the blades.

  The developer having a low toner concentration peeled off from the developing sleeve 120 falls on the first stirring / conveying member 123 and is stirred and conveyed in the axial direction by the first stirring / conveying member 123 in the axial direction. This is passed to the second agitating and conveying member 124 through an opening (not shown). The second agitating / conveying member 124 conveys the developer and the toner replenished from the replenishing port 118 of the developing container 110 in a reverse rotation to the above while agitating, and an opening (not shown) at the other end of the partition wall 140. And return to the first stirring and conveying member 123 side.

  Next, the process cartridge and the electrophotographic apparatus according to the present invention will be described.

  FIG. 3 shows a schematic configuration of an electrophotographic apparatus having a process cartridge containing an organic photoreceptor.

  In FIG. 3, reference numeral 1 denotes a drum-shaped organic photoconductor (photoconductor), which is driven to rotate about a shaft C in a direction indicated by an arrow at a predetermined peripheral speed. In the rotation process, the organic photoreceptor 1 is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging means 2 and then output from an exposure means (not shown) such as slit exposure or laser beam scanning exposure. Exposure light 3 (exposure means) that has been emphasized and modulated in response to a time-series electrical digital image signal of target image information. In this way, electrostatic latent images corresponding to the target image information are sequentially formed on the peripheral surface of the organic photoreceptor 1.

  The formed electrostatic latent image is then developed with toner by the developing means 4 and taken out from a paper feed unit (not shown) between the organic photoreceptor 1 and the transfer means 5 in synchronization with the rotation of the organic photoreceptor 1. The toner images formed and supported on the surface of the organic photoreceptor 1 are sequentially transferred by the transfer means 5 to the fed transfer material P.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the organic photoreceptor, introduced into the image fixing means 24, and subjected to image fixing to be printed out as an image formed product (print, copy).

  After the image transfer, the surface of the organic photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 6, and is further subjected to a static elimination process with pre-exposure light Pex from a pre-exposure unit (not shown). Used repeatedly for image formation. When the charging unit 2 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, among the above-mentioned components such as the organic photoreceptor 1, the charging unit 2, the developing unit 4 and the cleaning unit 6, a plurality of components are housed in a container PC and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the charging unit 2, the developing unit 4 and the cleaning unit 6 is integrally supported together with the organic photoreceptor 1 to form a cartridge, which can be attached to and detached from the apparatus body using a guide unit AN such as a rail of the apparatus body. It can be a process cartridge.

  An embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described as a full-color image forming apparatus to which the present invention is applied.

  FIG. 4 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  An image forming unit 10Y that forms a yellow image has a charging unit 2Y, an exposing unit 3Y, a developing unit 4Y, and a primary transfer unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A primary transfer roller 5Y and a cleaning means 6Y are provided. An image forming unit 10M that forms a magenta image includes a drum-shaped photoconductor 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoconductor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, a primary transfer roller 5C as a primary transfer unit, It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure means 3Y, the exposure means 3Y includes an LED in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y and an imaging element (trade name; Selfoc lens), or A laser optical system or the like is used.

In the image forming method of the present invention, when an electrostatic latent image is formed on a photoreceptor, it is preferable to perform image exposure using an exposure beam having a spot area of 2000 μm ² or less. Even when such small-diameter beam exposure is performed, the organic photoreceptor of the present invention can faithfully form an image corresponding to the spot area. A more preferable spot area is 100 to 1000 μm ² . As a result, an electrophotographic image having a gradation of not less than 800 dpi (dpi is the number of dots per 2.54 cm) can be achieved.

The spot area of the exposure beam is a light intensity distribution plane appearing on the cut surface when the exposure beam is cut along a plane perpendicular to the beam, and in a region where the light intensity is 1 / e ² or more of the maximum peak intensity. It means the corresponding area.

Examples of the light beam used include a scanning optical system using a semiconductor laser, and a solid state scanner such as an LED or a liquid crystal shutter. The light intensity distribution includes a Gaussian distribution and a Lorentz distribution, but 1 / e of each peak intensity. ^The area up to ² is the spot area.

  The endless belt-shaped intermediate transfer body unit 7 is an endless belt-shaped intermediate transfer body 70 (transfer medium) as a semiconductive endless belt-shaped second image carrier that is wound around a plurality of rollers and rotatably supported. ).

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material (transfer medium) P as a transfer material (support for supporting the final fixed image: for example, plain paper, transparent sheet, etc.) housed in the paper feed cassette 20 is fed by the paper feeding means 21. Then, after passing through a plurality of intermediate rollers 22A, 22B, 22C, 22D, and a registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to collectively transfer color images. The The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, the transfer medium refers to a transfer medium for a toner image on a photosensitive member such as an intermediate transfer member or a transfer material.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in pressure contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in pressure contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b is brought into pressure contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  Next, FIG. 5 shows a color image forming apparatus using the organic photoreceptor of the present invention (a copying machine having at least a charging means, an exposing means, a plurality of developing means, a transfer means, a cleaning means and an intermediate transfer body around the organic photoreceptor. 1 is a sectional view of the configuration of a laser beam printer). The belt-shaped intermediate transfer body 70 uses an elastic body having a medium resistance.

  Reference numeral 1 denotes a rotary drum type photoconductor that is repeatedly used as an image forming body, and is rotationally driven in a counterclockwise direction indicated by an arrow at a predetermined peripheral speed.

  During the rotation process, the photosensitive member 1 is uniformly charged to a predetermined polarity and potential by the charging unit 2 and then modulated in accordance with a time-series electric digital pixel signal of image information by an image exposure unit 3 (not shown). An electrostatic latent image corresponding to a yellow (Y) color component image of a target color image is formed by receiving image exposure with scanning exposure light or the like by a laser beam.

  Next, the electrostatic latent image is developed with yellow toner as the first color by yellow (Y) developing means (yellow color developing device) 4Y. At this time, the second to fourth developing means (magenta developer, cyan developer, black developer) 4M, 4C, and 4Bk are not activated and do not act on the photoreceptor 1. The yellow toner image of the first color is not affected by the second to fourth developing devices.

  The intermediate transfer member 70 is stretched by rollers 79a, 79b, 79c, 79d, and 79e, and is driven to rotate in the clockwise direction at the same peripheral speed as the photosensitive member 1.

  The first color yellow toner image formed and supported on the photosensitive member 1 is applied to the intermediate transfer member 70 from the primary transfer roller 5a in the process of passing through the nip portion between the photosensitive member 1 and the intermediate transfer member 70. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer body 70 by the electric field formed by the primary transfer bias.

  The surface of the photoreceptor 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer body 70 is cleaned by the cleaning device 6a.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black (black) toner image are sequentially superimposed and transferred onto the intermediate transfer body 70 to correspond to the target color image. A superimposed color toner image is formed.

  The secondary transfer roller 5b is supported in parallel with the secondary transfer counter roller 79b so as to be separated from the lower surface of the intermediate transfer body 70.

  The primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive member 1 to the intermediate transfer member 70 has a polarity opposite to that of the toner and is applied from a bias power source. The applied voltage is, for example, in the range of +100 V to +2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive member 1 to the intermediate transfer member 70, the secondary transfer roller 5b and the intermediate transfer member cleaning means 6b can be separated from the intermediate transfer member 70. is there.

  When the superimposed color toner image transferred onto the belt-shaped intermediate transfer member 70 is transferred to the transfer material P, which is the second image carrier, the secondary transfer roller 5b is brought into contact with the belt of the intermediate transfer member 70. At the same time, the transfer material P is fed from the pair of paper registration rollers 23 through the transfer paper guide to the belt of the intermediate transfer body 70 to the contact nip with the secondary transfer roller 5b at a predetermined timing. A secondary transfer bias is applied to the secondary transfer roller 5b from a bias power source. By this secondary transfer bias, the superimposed color toner image is transferred (secondary transfer) from the intermediate transfer body 70 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing means 24 and heated and fixed.

  The organophotoreceptor of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers, but also displays, recordings, light printing, plate making and facsimiles using electrophotographic technology. The present invention can be widely applied to such devices.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, the aspect of this invention is not limited to this. In the following text, “part” means “part by mass”.

Production of photoconductor (production of photoconductor 1)
Intermediate layer 60 g of polyamide resin (Amilan CM-8000: manufactured by Toray Industries, Inc.) was dissolved and dispersed in 1600 ml of methanol to prepare an intermediate layer composition solution, and dip coating method on a washed cylindrical aluminum substrate (diameter: 80 mm) Was applied to form an intermediate layer having a thickness of 0.3 μm.

Charge generation layer 60 g of Y-type titanyl phthalocyanine and 700 g of a silicone resin solution (KR5240, 15% xylene-butanol solution: manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed with a coating composition solution of 2000 ml of 2-butanone, and a sand mill is used. For 10 hours to prepare a charge generation layer coating solution. This charge generation layer coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.2 μm.

Charge transport layer 200 g of charge transport material (Exemplary Compound C-126), 300 g of polyarylate (Po-2: viscosity average molecular weight 40,000) and antioxidant (Exemplary Compound AO2-1) 12 g, 2000 ml of monochlorobenzene A mixed solvent of dichloromethane / dichloromethane (1/1) was mixed and dissolved to prepare a charge transport layer coating solution. This charge transport coating solution was applied onto the charge generation layer by a dip coating method, followed by heating and drying at 100 ° C. for 40 minutes to form a charge transport layer having a thickness of 20 μm.

Production of photoconductors 2 to 5 In the production of photoconductor 1, the charge transport material and polyarylate of the charge transport layer were changed as shown in Table 1, and photoconductors 2 to 5 were produced. However, PC-A of the photoreceptor 5 is a polycarbonate (viscosity average molecular weight 40,000) having the following structure, and CR is a charge transporting material having the following structure.

  The weights We / Wt of these photoreceptors 1 to 5 were measured and listed in Table 1.

  A toner used in the present invention was prepared as follows.

Preparation of colored particles 1Bk 0.90 kg of sodium n-dodecyl sulfate and 10.0 l of pure water are added and dissolved by stirring. To this solution, 1.20 kg of Legal 330R (Cabot Black Carbon Black) was gradually added and stirred well for 1 hour, followed by continuous dispersion for 20 hours using a sand grinder (medium disperser). This is referred to as “colorant dispersion 1”. A solution composed of 0.055 kg of sodium dodecylbenzenesulfonate and 4.0 l of ion-exchanged water is referred to as “anionic surfactant solution A”.

  A solution composed of 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct and 4.0 l of ion-exchanged water is referred to as “nonionic surfactant solution B”. A solution obtained by dissolving 223.8 g of potassium persulfate in 12.0 l of ion-exchanged water is referred to as “initiator solution C”.

  Into a 100-liter GL (glass lining) reaction kettle equipped with a temperature sensor, a cooling pipe, and a nitrogen introducing device, a WAX emulsion (a polypropylene emulsion having a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration = 29.9%) ) Put 3.41 kg, the total amount of “anionic surfactant solution A” and the total amount of “nonionic surfactant solution B”, and start stirring. Then, 44.0 l of ion exchange water is added.

  Heating was started and when the liquid temperature reached 75 ° C., the entire amount of “Initiator Solution C” was added dropwise. Thereafter, while controlling the liquid temperature at 75 ° C. ± 1 ° C., 12.1 kg of styrene, 2.88 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 548 g of t-dodecyl mercaptan are added dropwise. After completion of the dropwise addition, the liquid temperature was raised to 80 ° C. ± 1 ° C. and stirring was performed for 6 hours. Next, the liquid temperature is cooled to 40 ° C. or lower, stirring is stopped, and the mixture is filtered with a pole filter, and this is designated as “latex (1) -A”.

  The glass transition temperature of the resin particles in the latex (1) -A was 57 ° C., the softening point was 121 ° C., the molecular weight distribution was weight average molecular weight = 17,000, and the weight average particle size was 120 nm.

  A solution obtained by dissolving 0.055 kg of sodium dodecylbenzenesulfonate in 4.0 l of ion-exchanged pure water is referred to as “anionic surfactant solution D”. Further, a solution obtained by dissolving 0.014 kg of nonylphenol polyethylene oxide 10 mol adduct in 4.0 l of ion-exchanged water is referred to as “nonionic surfactant solution E”.

  A solution obtained by dissolving 200.7 g of potassium persulfate (manufactured by Kanto Chemical Co., Ltd.) in 12.0 l of ion-exchanged water is referred to as “initiator solution F”.

  A WAL emulsion (polypropylene emulsion with a number average molecular weight of 3000: number average primary particle size = 120 nm / solid content concentration of 29.9%) was added to a 100-liter GL reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a comb-shaped baffle. .41 kg, the total amount of “anionic surfactant solution D” and the total amount of “nonionic surfactant solution E” are added, and stirring is started. Next, 44.0 l of ion exchange water is added. Heating is started, and when the liquid temperature reaches 70 ° C., “initiator solution F” is added. Next, a solution prepared by previously mixing 11.0 kg of styrene, 4.00 kg of n-butyl acrylate, 1.04 kg of methacrylic acid, and 9.02 g of t-dodecyl mercaptan is dropped. After completion of the dropwise addition, the liquid temperature was controlled at 72 ° C. ± 2 ° C., and the mixture was heated and stirred for 6 hours. Furthermore, the liquid temperature was raised to 80 ° C. ± 2 ° C., and the mixture was heated and stirred for 12 hours. The liquid temperature is cooled to 40 ° C. or lower, and stirring is stopped. It filtered with the pole filter and this filtrate was set to "latex (1) -B."

  The glass transition temperature of the resin particles in the latex (1) -B was 58 ° C., the softening point was 132 ° C., the molecular weight distribution was weight average molecular weight = 245,000, and the weight average particle size was 110 nm.

  A solution obtained by dissolving 5.36 kg of sodium chloride as a salting-out agent in 20.0 l of ion-exchanged water is referred to as “sodium chloride solution G”.

  A solution obtained by dissolving 1.00 g of a fluorine-based nonionic surfactant in 1.00 l of ion-exchanged water is referred to as “nonionic surfactant solution H”.

  Latex (1) -A = 20.0 kg and latex (1) -B = 5 prepared above were added to a 100 l SUS reaction kettle equipped with a temperature sensor, a cooling pipe, a nitrogen introducing device, and a particle size and shape monitoring device. .2 kg, colorant dispersion 1 = 0.4 kg, and 20.0 kg of ion exchange water are added and stirred. Next, the mixture is heated to 40 ° C., and sodium chloride solution G, isopropanol (manufactured by Kanto Chemical Co.) 6.00 kg, and nonionic surfactant solution H are added in this order. Then, after standing for 10 minutes, the temperature rise was started, the temperature was raised to a liquid temperature of 85 ° C. in 60 minutes, and the particles were heated and stirred at 85 ± 2 ° C. for 0.5 to 3 hours while being salted out / fused. Grow. Next, 2.1 l of pure water is added to stop the particle size growth.

  In a 5 liter reaction vessel equipped with a temperature sensor, a cooling tube, a particle size and shape monitoring device, 5.0 kg of the fused particle dispersion prepared above was placed, and the liquid temperature was 85 ° C. ± 2 ° C. and 0.5 kg. The shape was controlled by heating and stirring for ˜15 hours. Then, it cools to 40 degrees C or less and stops stirring. Next, using a centrifugal separator, classification is performed in the liquid by a centrifugal sedimentation method, followed by filtration through a sieve having an opening of 45 μm, and this filtrate is used as the associated liquid (1). Next, using a Nutsche, the wet cake-like non-spherical particles were collected from the associated liquid (1) by filtration. Thereafter, it was washed with ion exchange water.

  The non-spherical particles were dried at a suction air temperature of 60 ° C. using a flash jet dryer and then dried at a temperature of 60 ° C. using a fluidized bed dryer. In the monitoring of the salting-out / fusion stage and the shape control process, by controlling the number of revolutions of stirring and the heating time, the coefficient of variation of the shape and the shape factor is controlled, and further the particle size and particle size distribution by subclassification in the liquid. Was adjusted to obtain colored particles 1Bk shown in Table 2.

Preparation of colored particles 1Y In the preparation of the colored particles 1Bk, instead of 1.20 kg of Legal 330R (carbon black manufactured by Cabot), C.I. I. Colored particles 1Y shown in Table 2 were obtained in the same manner except that CI Pigment Yellow 185 and 1.00 kg were used.

Production of colored particles 1M In the production of colored particles 1Bk, C.I. I. Colored particles 1M shown in Table 2 were obtained in the same manner except that CI Pigment Red 122 was used.

Preparation of colored particles 1C In the preparation of colored particles 1Bk, instead of 1.30 kg of Legal 330R (Cabot carbon black), C.I. I. Colored particles 1C shown in Table 2 were obtained in the same manner except that CI Pigment Blue 15: 3 and 0.8 kg were used.

  The above colored particles 1Bk, 1Y, 1M, and 1C and the external additives shown in Table 4 below are added as shown in Table 3 and mixed with a Henschel mixer under a rotation condition of 30 m / sec, and toner 1Bk (1Y, 1M). 1C) to 7Bk.

Production of Developer A developer having a toner concentration of 6% by mixing each of the “Toner 1Bk (1Y, 1M, 1C)” to “Toner 7Bk” and a ferrite carrier coated with a silicone resin and having a volume average particle diameter of 60 μm. Was used for printing evaluation. This developer is designated as “Developer 1Bk (1Y, 1M, 1C)” to “Developer 7Bk” corresponding to the toner.

Evaluation 1 (Evaluation by counter development method)
The obtained developer and photoconductor are combined as shown in Table 5 (combination Nos. 1 to 11), and a commercially available full-color composite machine 8050 (manufactured by Konica Minolta Business Technologies, Inc.) remodeling machine (using an intermediate transfer member) A tandem-type full-color MFP 8050 (process speed 220 mm / sec) was mounted on a counter development system), and monochrome image evaluation using black toner was performed. Using an original image having a white background portion, a solid black portion solit image portion, a character image portion, and a halftone image portion, it was continuously copied and evaluated on A4 paper. Specifically, evaluation images were taken out at the start and every 10,000 sheets, and a total of 300,000 sheets were printed and evaluated. Evaluation items and evaluation criteria are shown below.

Evaluation condition Photoconductor linear velocity: 220 mm / sec
Line speed of developing sleeve: 400mm / sec
(1) Image evaluation Reduced tip density A halftone image was prepared and evaluated.

  (Double-circle): Generation | occurrence | production of density | concentration fall of a front-end | tip part is not seen, but a halftone image is reproduced clearly (very good).

  ○: The halftone image is clearly reproduced, but there is a drop in the tip density of less than 0.04 in reflection density (no problem in practical use).

  X: The half-tone image has a drop in tip density of 0.04 or more in reflection density (practically problematic).

Toner Filming The photoreceptor was taken out every 10,000 prints, and toner filming was observed and evaluated according to the following criteria.

◎; Almost no toner filming and no corresponding spotted image defect (good)
○: Small toner filming is observed, but the corresponding spotted image defect is not observed (a level that causes no problem in practical use).
X: Toner filming occurs, and corresponding spot-like image defects are seen (a level that causes a practical problem)
Evaluation of cleaning property ○: Good cleaning with no toner slipping or blade turning (good)
×: The cleaning blade is worn and toner slips out or the blade is turned up, and the residual toner on the photoconductor is not sufficiently cleaned (unusable)
Evaluation of scratches A: The surface of the photoconductor is uniform and the halftone image is good (good)
○: The surface of the photoconductor is slightly rough, but the halftone image is good (practical)
×: Many scratches occur on the surface of the photoconductor, and the halftone image is scratched (not practical)
The results are shown in Table 5.

  As can be seen from Table 5, in the image evaluation produced by the counter development method, the organic photoconductor has an elastic deformation amount (We20) with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoconductor. A combination in which the percentage of total work (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and the toner contains an inorganic external additive having a number average primary particle size of 100 to 1000 nm (No. ... 1 to 10) have good characteristics in all the evaluation items of the density reduction of the tip, toner filming, cleaning properties, and scratches. Further, in the combination (No. 11) using the photoconductor 5 in which the percentage ((We20 / Wt20) × 100) of the elastic deformation amount (We20) and the total work amount (Wt20) is less than 45.0, the density of the tip end portion is lowered. The occurrence of scratches is remarkable.

Evaluation 2 (Evaluation using the parallel development method)
The evaluation performed in Evaluation 1 was evaluated by a parallel development system in which the traveling directions of the photosensitive member and the developing sleeve proceed in parallel.

Evaluation condition Photoconductor linear velocity: 220 mm / sec
Line speed of developing sleeve: 350 mm / sec
As a result, the difference between the invention of the evaluation 1 and the comparative example did not appear clearly, and in all of the invention and the comparative example, no decrease in tip density or fog was observed, but compared with the counter development method. The image density was lowered, and an electrophotographic image with insufficient density was obtained.

Evaluation 3 (Evaluation by counter development method)
As shown in Table 6, a combination of a photoconductor and a toner (combination No. 14) is converted into a commercially available full-color composite machine 8050 (manufactured by Konica Minolta Business Technologies, Inc.), a tandem type full-color composite using an intermediate transfer member The machine 8050 (process speed 220 mm / sec) was mounted on a counter development system), and color images were evaluated. The evaluation was made by copying on A4 paper using an original image having a white background portion, a solid black portion, and a solid image portion and a character image portion of red, green, and blue. Specifically, a total of 300,000 sentence copy images were printed and evaluated at the start and every 10,000 sheets. In addition to the evaluation performed in Evaluation 1, evaluation items were added by adding the following color reproducibility.

Photoconductor linear velocity: 220 mm / sec
Line speed of developing sleeve: 400mm / sec
Color reproducibility The color of the solid image portion of the secondary color (red, blue, green) in each of the Y, M, and C toners of the first image and the 100th image is measured by “Macbeth Color-Eye 7000”, and CMC The color difference between the first and 100th sheets of each solid image was calculated using the (2: 1) color difference formula.

A: Color difference is 3 or less (good)
×: Color difference is greater than 3 (practical problem and impractical)
The results are shown in Table 6.

  As is clear from Table 6, the combination (No. 14) of the present invention for both the organic photoreceptor and the developer is good in each evaluation item of the density reduction of the tip portion, toner filming, cleaning properties, scratches, and color reproducibility. I'm getting results.

Evaluation 4 (Evaluation by counter development method)
Evaluation was performed in the same manner as in Evaluation 1 except that the linear velocity of the photosensitive member and the developing sleeve performed in Evaluation 1 was changed to the following conditions.

Photoconductor linear velocity: 350 mm / sec
Line speed of developing sleeve: 600mm / sec
As a result, the evaluation results of the present invention and the comparative example almost equivalent to the evaluation 1 were obtained.

Evaluation 5 (Evaluation by counter development method)
In the combination of evaluation 1, Evaluation was performed in the same manner as in Evaluation 1 using the combinations of 1, 10, and 11 under the following linear velocity conditions of the photoreceptor and the developing sleeve.

Photoconductor linear velocity: 150 mm / sec
Line speed of developing sleeve: 250 mm / sec
The results are shown in Table 7.

  From the results shown in Table 7, when the process speed (the linear velocity of the photosensitive member) is less than 200 mm / second, the combination No. in which the photosensitive member does not satisfy the conditions of the present invention. 11 is used, combination no. Compared with 1 and 10, the difference in evaluation results is small.

(A) is explanatory drawing which shows the projection image of a toner particle without an angle | corner, (b) and (c) are explanatory drawings which show the projection image of a toner particle with an angle | corner, respectively. It is a figure which shows the cross section of the developing device of the counter direction developing method. 1 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus having a process cartridge including an organic photoreceptor. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention. 1 is a cross-sectional view of a color image forming apparatus using an organic photoreceptor of the present invention. It is a figure which shows an example of the measurement data of a work function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic photoreceptor C axis | shaft 2 Charging means 3 Exposure light 4 Developing means 5 Transfer means P Transfer material 24 Fixing means 6 Cleaning means Pex Pre-exposure light PC Process cartridge container AN Guide means 101 Organic photoreceptor 102 Developing apparatus 110 Developing container 118 Replenishment Mouth 120 Developing sleeve 121 Magnet 122 Developing blade 123 First agitating and conveying member 124 Second agitating and conveying member 128 Screw blade 130 Plate-like projection 140 Partition N1 Developing magnetic pole N2 Second conveying magnetic pole S1 Pumping magnetic pole S2 Third conveying magnetic pole S3 First conveying Magnetic pole P1 Developer drop position Q1 Pumping position

Claims (8)

An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In the image forming method for visualizing an electrostatic latent image into a toner image, the organic photoconductor is subjected to an elastic deformation amount (We20) and a total work with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoconductor. The percentage of the amount (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and the electrostatic latent image is converted into a toner image by rotating the developing sleeve in the counter direction with respect to the rotating direction of the organic photoreceptor rotating. An image forming method characterized in that the image is visualized. A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming method, each color toner image is formed on an organic photoreceptor using a toner whose color is changed, and the color toner image is transferred from the organic photoreceptor to a transfer medium to form a color image. However, the percentage of the elastic deformation (We20) and the total work (Wt20) with respect to a constant load indenter (total load is 20 mN) weighted from the surface of the photoreceptor ((We20 / Wt20) × 100) There are at 45.0 or more, with respect to the rotation direction of the organic photoreceptor which rotates the developing sleeve, an image forming method which comprises causing to rotate in the counter direction to the electrostatic latent image into a toner image. An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In the image forming method for developing an electrostatic latent image into a toner image, the surface layer of the organic photoreceptor contains polyarylate, and the toner contains an inorganic external additive having a number average primary particle size of 100 to 1000 nm. And an electrostatic latent image is visualized as a toner image by rotating the developing sleeve in a counter direction with respect to the rotation direction of the organic photoreceptor rotating. A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming method, each color toner image is formed on an organic photoreceptor using a toner whose color is changed, and the color toner image is transferred from the organic photoreceptor to a transfer medium to form a color image. The surface layer of the toner comprises polyarylate, the toner contains an inorganic external additive having a number average primary particle diameter of 100 to 1000 nm, and the rotating method of the organic photoreceptor rotating the developing sleeve To an image forming method which comprises causing to rotate in the counter direction to the electrostatic latent image into a toner image. The image forming method according to claim 1, wherein the toner contains an inorganic external additive having a number average primary particle size of 100 to 1000 nm. The image forming method according to claim 1, wherein the toner is a polymerized toner. An electrostatic latent image is formed on a cylindrical organic photosensitive member at a process speed of 200 mm / sec or more, and a cylindrical developing sleeve carrying a developer containing toner is brought into contact with the organic photosensitive member, thereby In an image forming apparatus that visualizes an electrostatic latent image into a toner image, the organic photoconductor is subjected to an elastic deformation amount (We20) and a total work with respect to a constant load indenter (total load is 20 mN) applied from the surface of the photoconductor. The percentage of the amount (Wt20) ((We20 / Wt20) × 100) is 45.0 or more, and the electrostatic latent image is converted into a toner image by rotating the developing sleeve in the counter direction with respect to the rotating direction of the organic photoreceptor rotating. An image forming apparatus characterized in that the image is visualized. A process speed is 200 mm / sec or more, an electrostatic latent image is formed on a cylindrical organic photosensitive member, and a cylindrical developing sleeve carrying a developer containing toner is disposed in contact with the organic photosensitive member. A plurality of image forming units each having a developing unit that visualizes the electrostatic latent image into a toner image and a transfer unit that transfers the toner image formed on the organic photosensitive member to a transfer medium are provided. In the image forming apparatus for forming a color image by forming each color toner image on an organic photoconductor using a toner whose color is changed to the above, and transferring the color toner image from the organic photoconductor to a transfer medium, the organic photoconductor However, the percentage of the elastic deformation (We20) and the total work (Wt20) with respect to a constant load indenter (total load is 20 mN) weighted from the surface of the photoreceptor ((We20 / Wt20) × 100) There are at 45.0 or more, with respect to the rotation direction of the organic photoreceptor which rotates the developing sleeve, an image forming apparatus for causing the electrostatic latent image is rotated in the counter direction is visualized into a toner image.

Images