JP2007033667A - Developing method and developer carrier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer carrier which is capable of obtaining images of high quality free from fog and sweepings in any environment and free from image defects such as a void due to leakage, for a long period of time in a nonmagnetic one-component jumping development system. <P>SOLUTION: In a developing method of applying at least an alternating voltage to a developer carrier to develop an electrostatic latent image carried on an electrostatic latent image carrier into a visible image, a maximum field intensity between the developer carrier and the electrostatic latent image carrier is 6.0×10<SP>6</SP>to 2.0×10<SP>7</SP>V/m, and the developer carrier includes at least a base member and a resin coating layer having fine conductive particles on a surface of the base member, and a ten-point average roughness Rz of a non-coat part of the developer carrier is 1.5 to 5.0 μm, and an initial wear height Rpk of the non-coat part is 0.1 to 0.6 μm, and a ten-point average roughness Rz of a coat part is 2.0 to 9.0 μm, and an initial wear height Rpk of the coat part is 0.3 to 2.5 μm, and a volume resistance of the resin coating layer is 10<SP>5</SP>to 10<SP>11</SP>Ωcm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing method for developing and developing a latent image formed on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording derivative, and a developer carrier used therefor.

  Development methods in electrophotography are mainly divided into a one-component development method and a two-component development method.

  Conventionally, two-component developers have been used to output these full-color images. However, in recent years, a developing device using a one-component developing system is often used for the purpose of reducing the weight and size of the electrophotographic apparatus.

  In the one-component development system, a non-magnetic toner containing no magnetic material and a magnetic toner containing a magnetic material may be used in the toner, but when using for a full color image, the magnetic material is included from the viewpoint of color reproducibility. Non-magnetic single component developers are often used.

  As a developing device using a one-component developing system, an electrostatic latent image is formed on the surface of a photosensitive drum as an electrostatic latent image holding member, and the friction between the developer carrying member and the toner and / or on the developer carrying member. The toner is positively or negatively charged by friction with the developer layer thickness regulating member for regulating the toner coat amount, and the toner is applied thinly on the developer carrying member, and the developer carrying member is applied to the photosensitive drum. The developer is transported to a development area that is in close proximity to the surface, and a development bias consisting of an AC component and a DC component is applied in the development area to develop the toner by flying and adhering to the electrostatic latent image on the photosensitive drum surface. A jumping development method for visualizing an electrostatic latent image as a toner image is known. As these developing biases, AC biases such as a rectangular wave bias and a duty bias are used. By applying an AC bias between the developer carrying member and the photosensitive member, various image quality due to the reciprocating motion of the toner can be obtained. Problems are likely to occur.

  One example is a so-called sweeping phenomenon in which, when an image in which a solid white image is followed by a solid image is output, the solid rear end image becomes significantly darker than the other portions. When this phenomenon occurs, it becomes impossible to obtain a uniform image quality in a low-density image such as a halftone image, and it becomes more difficult to obtain a high-quality image when overlapping each color toner image like a color image. .

  The following is a so-called fogging phenomenon in which toner flies to a non-image area on the photoreceptor and is transferred onto paper. This is mainly because the toner charge amount distribution on the developer carrying member is non-uniform. Even if there is a toner that has been overcharged or a toner having a significantly low charge amount. Will occur.

  To solve these problems, many proposals have been made from toner formulations and manufacturing methods. However, with the rapid progress in image quality, ultra-miniaturization, and energy saving in recent years, development systems have been updated. There is a need for improvements.

  For example, Patent Document 1 discloses a developing device in which a plate-like member made of an electrode member is provided between a photosensitive drum and a developer carrier in order to suppress the reciprocal movement of toner. However, the improvement effect is insufficient in a developing device using a non-magnetic one-component developer.

  Further, Patent Document 2 describes a fall between the toner urging process (A) in the developer carrying member direction and the toner urging process (B) in the photosensitive drum direction in one cycle of the AC component of the developing electric field. The time T12 of the process (C) and the time T11 of the process (B) are defined so as to satisfy 10.0 ≦ T11 / (T11 + T12) × 100 ≦ 90.0, and according to the change in atmospheric pressure (B ) Has been proposed which has a means for adjusting the potential Vmax. However, such an image forming apparatus may be expensive because the waveform generator becomes complicated and an air pressure sensor or the like is required. In addition, if the chargeability of the toner on the developer carrying member becomes non-uniform due to changes in the environmental conditions of temperature and humidity used or repeated copying, deterioration of sweeping, image density reduction, fogging, etc. may occur. .

  There is a method of narrowing the distance (S-D distance) between the photosensitive drum and the developer carrying member in order to suppress the reciprocating movement of the toner. However, in this case, the distance and time that the toner is flying is shortened, so that toner scattering and fogging are suppressed, and the followability to the latent image on the photosensitive drum is further improved, so that high-resolution image quality may be obtained. There is. However, since it is necessary to reduce the thickness of the toner coat layer, it is difficult to control the charge amount distribution, and image defects such as a decrease in density and occurrence of white spots due to a developing bias leak easily occur.

  On the other hand, as a method for improving the developer carrying member, a method using a developer carrying member in which a coating layer formed by dispersing conductive fine powders such as crystalline graphite and carbon in a resin is provided on a metal substrate. Are disclosed in Patent Documents 3 and 4. By using this method, it is recognized that the above-mentioned charge-up phenomenon is greatly reduced, but the sweeping when using a non-magnetic toner is still insufficient and is required for a high-quality color image. The level has not been reached.

  Furthermore, when a large amount of the above powder is added, the coating layer becomes brittle and becomes easy to scrape, and the surface shape becomes non-uniform, and the surface roughness and surface composition of the coating layer change when the durable use is promoted. As a result, poor toner conveyance and non-uniform toner chargeability are likely to occur.

  Patent Document 5 proposes a developer carrying member in which a conductive coating layer in which conductive fine powders such as crystalline graphite and carbon, and spherical particles are dispersed in a resin is provided on a metal substrate. . In this developer carrier, the wear resistance of the coating layer is improved, the shape of the surface of the coating layer is made uniform, and the change in surface roughness due to durable use is relatively small. However, the charge of the toner can be made uniform to some extent, and problems such as image density reduction and image density unevenness due to charge-up are reduced, and the image quality tends to be stabilized. However, even with this developer carrier, sweeping when non-magnetic toner is used is still insufficient. Furthermore, if the non-magnetic toner is spherical, it will be insufficient for stabilizing the image quality in a low-temperature and low-humidity environment or a high-temperature and high-humidity environment, and white spots due to leakage are likely to occur if an attempt is made to ensure sufficient developability with a development bias. Become.

  Patent Document 6 proposes a developer carrier having a resin coating layer containing graphite fine particles on a sandblasted substrate. In this developer carrying member, peeling of the film from the substrate is suppressed, and an image having a good density can be obtained over a long period of time. However, this is a proposal in which both the average surface roughness of the substrate and the average surface roughness of the surface layer are rough. In recent toners with small particle sizes and spheroids, appropriate transportability and charge imparting properties are obtained. In other words, problems such as uneven coating, charge density reduction, and fogging are likely to occur.

  Patent Document 7 proposes a developing roller characterized in that a resin layer film of a phenol resin containing a conductivity imparting material having a surface roughness rougher than that of a substrate is formed on a substrate subjected to a roughening treatment. Has been. In this developing roller, by roughening the substrate, the adhesion of the film is improved and the surface strength is increased, and further, the surface roughness of the substrate is made smaller than the surface roughness of the resin film layer. Even if the film thickness is thin, the substrate can be prevented from being exposed and image deterioration due to long-term use can be suppressed. However, since the layer thickness of the resin film layer is not uniform as a whole, the charge amount distribution of the toner coated on the developing roller differs between the upper layer and the lower layer, and problems such as selective development tend to occur. Further, in the portion where the film thickness is thin, the resistance of the coat layer is lowered, the leakage resistance against the photoreceptor is lowered, and image defects such as white spots are liable to occur.

  In particular, in the case of using finely divided and spheroidized toner in recent years, the formation of the toner layer on the developer carrying member has become difficult to control depending on the environmental characteristics, the physical properties of the toner, the state of the surface of the developer carrying member, and the like. Yes. Further, in the development system for the next generation ultra-high image quality, stricter charge amount control is required to suppress the reciprocating movement of the toner between SD, and the toner coat layer is uniformly charged and narrowed. Improvement of leak resistance between SD is desired.

Although various improvements have been attempted as described above, there is actually no development method that can solve all of these problems.
Japanese Patent Laid-Open No. 08-022185 Japanese Patent Laid-Open No. 07-134480 Japanese Patent Laid-Open No. 02-105181 Japanese Unexamined Patent Publication No. 03-036570 Japanese Patent Laid-Open No. 03-200986 JP 05-006089 A JP-A-11-249432

  An object of the present invention is to provide a developing method that solves all of the above problems and a developer carrying member used therefor.

  That is, in a non-magnetic one-component jumping development system, even in a developing device having a small SD distance and a high electric field strength, there is no occurrence of fogging or sweeping, and there is no image defect such as white spots due to leakage. An object of the present invention is to provide a developing method capable of obtaining an image and a developer carrying member used therefor.

In order to achieve the above object, the present invention is arranged such that a developer carried on a layer on the surface of a developer carrying member is opposed to the developer carrying member through a predetermined distance (distance between S and D). In the development area formed at the closest part to the developer carrier of the electrostatic latent image carrier, an alternating voltage is applied to the developer carrier, and the developer carried on the surface of the developer carrier is electrostatically charged. A developing method for developing an electrostatic latent image conveyed to a latent image carrier and carried on the electrostatic latent image carrier,
(1) The maximum electric field strength between the developer carrier and the electrostatic latent image carrier is 6.0 × 10 ^{6 to} 2.0 × 10 ⁷ V / m,
(2) The developer carrier has at least a substrate and a resin coating layer containing conductive fine particles on the surface of the substrate, and the developer coating resin coating layer facing the electrostatic latent image carrier is formed. 10-point average roughness Rz of the non-coated part is 1.5 to 5.0 μm, initial wear height Rpk is 0.1 to 0.6 μm, and developer carrying facing the electrostatic latent image carrier The 10-point average roughness Rz of the coating part on which the resin coating layer of the body is formed is 2.0 to 9.0 μm, the initial wear height Rpk is 0.3 to 2.5 μm, and the volume of the resin coating layer The developing method is characterized in that the resistance is 10 ⁵ to 10 ¹¹ Ω · cm.

Further, a developer carrier for carrying the developer in layers, an electrostatic latent image carrier disposed to face the developer carrier via a gap, and a power source for applying at least an alternating voltage to the developer carrier Have
The developer carrying member has at least a substrate and a resin coating layer containing conductive fine particles on the surface of the substrate, and the resin coating layer of the developer carrying member facing the electrostatic latent image carrier is not formed. 10-point average roughness Rz of 1.5 to 5.0 μm, initial wear height Rpk of 0.1 to 0.6 μm, and developer carrier resin facing electrostatic latent image carrier The ten-point average roughness Rz of the coating part on which the coating layer is formed is 2.0 to 9.0 μm, the initial wear height Rpk is 0.3 to 2.5 μm, and the volume resistance of the resin coating layer is 10 ⁵ to 10 ¹¹ Ω · cm.

  According to the present invention, the coating of the resin coating layer can be made uniform by controlling the surface roughness and volume resistance of the substrate of the developer carrying member and the resin coating layer containing the conductive fine particles coated on the substrate. In addition, it is possible to uniformly control the toner coating state and the charge amount distribution, and there is no fogging or sweeping in the jumping development system where the electric field strength between the photosensitive drum and the developer carrier is large. It is possible to provide a developing method excellent in leak resistance and a developer carrying member used therefor.

  The greatest feature of the present invention is that the developer carrying member having a resin coating layer containing conductive fine particles controls the surface roughness at the non-coated portion and the coated portion of the resin coating layer, and the resin coating layer The leak resistance can be further improved by controlling the volume resistance to a constant value.

  Since the leakage resistance has been further improved, the charge amount distribution of the toner coated on the developer carrier can be maintained uniformly and at a high charge amount even in a development system with a high electric field strength. It was possible to improve the leak resistance without impairing the performance.

(Developer carrier)
Conventionally, arithmetic average roughness Ra has been generally used as a parameter correlating with developer transportability as an index of the surface roughness of the developer carrying member. However, the present inventors have found that the value of the relatively large unevenness on the surface of the developer carrying member, the uniformity thereof, and the ratio of the protruding high protrusions tend to greatly depend on the toner coating state and leakage resistance. Therefore, as an index of the surface roughness of the developer carrying member, ten-point average roughness Rz representing large unevenness and initial wear height Rpk representing the ratio of protruding protrusions were used.

  The developer carrier of the present invention is disposed so as to face the electrostatic latent image carrier, and includes at least a substrate and a resin coating layer containing conductive fine particles formed on the substrate surface. The portion of the substrate surface that is not covered with the resin coating layer is referred to as “uncoated portion”. Since the uncoated portion of the substrate before the coating of the resin coating layer is exposed, the roughness of the non-coated portion represents the roughness (surface shape) of the lower layer (substrate) of the resin coating layer. The roughness of the part represents the roughness (surface shape) of the surface of the upper layer (resin coating layer).

  The ten-point average roughness Rz of the non-coated portion is 1.5 to 5.0 μm, the initial wear height Rpk is 0.1 to 0.6 μm, and the ten-point average roughness Rz of the coated portion is 2.0. It is preferable that the initial wear height Rpk is 0.3 to 2.5 μm.

  The Rz of the non-coated portion is 2.0 to 4.0 μm, the Rpk is 0.2 to 0.5 μm, the Rz of the coated portion is 3.0 to 7.0 μm, and the Rpk is 0.4 to 1. More preferably, it is 5 μm.

  That is, the aim of the present invention is to control the configuration of the resin coating layer by controlling the two surface shapes of the non-coated portion and the coated portion.

  When the Rz of the non-coated portion is less than 1.5 μm, the adhesion of the resin coating layer on the developer substrate is lowered, and defects such as peeling due to durability may easily occur. When Rz exceeds 5.0 μm, the coating thickness of the resin coating layer becomes non-uniform and it becomes difficult to control the value of volume resistance, and toner charging unevenness is likely to occur and problems such as fogging and sweeping are likely to occur. There is. When Rpk is less than 0.1 μm, the processing itself is very difficult, and the adhesion to the paint is small and defects such as coating unevenness are likely to occur. When the Rpk of the substrate is more than 0.6 μm, the protruding portion that protrudes when the resin coating layer is coated is used as a starting point, resulting in coating irregularities, which causes problems such as toner fusion and charge leakage. It may be easier.

  When the Rz of the coat portion is less than 2.0 μm, not only the image density is lowered because the amount of toner transported on the sleeve is reduced, but the toner coat may become non-uniform. When Rz exceeds 9.0 μm, the unevenness of the toner coat layer becomes too large, and the toner charge amount distribution may become non-uniform. Further, when Rpk is less than 0.3 μm, the charge of the coated toner is difficult to leak, so that overcharging is likely to occur, and image defects such as ghosts are likely to occur. When Rpk exceeds 2.5 μm, a large number of protruding protrusions are formed. From this point, the toner is likely to be fused, and the toner is not easily triboelectrically charged. There is a case where an increase or the like is likely to occur. Further, when the distance between the developer carrying member and the photosensitive member is small and the electric field strength is increased, a leak due to the developing bias may easily occur.

  The developer carrying member preferably has a Rz variation coefficient of 11% or less of the resin coating layer formed on the surface thereof. If this coefficient of variation is greater than 11%, the roughness of the sleeve surface is non-uniform, so that when the toner is triboelectrically charged, it is difficult to uniformly charge the toner, which may cause fogging and uneven density. is there. Furthermore, since the coating of the resin coating layer is not uniform as a whole, the leak resistance tends to deteriorate.

The volume resistance of the resin coating layer is preferably 10 ⁵ to 10 ¹¹ Ω · cm. By controlling the volume resistance of the resin coating layer within this range, excellent leakage resistance can be maintained without impairing development characteristics. When the volume resistance value of the resin coating layer is less than 10 ⁵ Ω · cm, the leak resistance is insufficient, and when it exceeds 10 ¹¹ Ω · cm, the toner adheres to the developer carrying member due to charge-up or the developer. In addition to the occurrence of charging failure, image quality deterioration such as image density reduction, image density unevenness, fogging, and sweeping becomes noticeable.

  The film thickness of the resin coating layer is preferably 12 to 50 μm, and more preferably 17 to 50 μm. When the film thickness is less than 12 μm, the required volume resistance cannot be maintained, and the leak resistance may be insufficient. When the film thickness exceeds 50 μm, it is difficult to obtain a uniform film thickness, Decrease in leak resistance may occur.

  The resin coating layer contains a binder resin. As the binder resin material, it is possible to use a known resin that has been conventionally used for a resin coating layer of a developer carrier. For example, thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, fiber resins, acrylic resins, epoxy resins, polyester resins, alkyd resins Thermal or photo-curable resins such as phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. can be used. Among them, those with releasability such as silicone resin and fluororesin, or excellent mechanical properties such as polyethersulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin, acrylic resin Is more preferable.

  The resin coating layer contains conductive fine particles in order to adjust the volume resistance value. Examples of the conductive fine particles include metal powders such as aluminum, copper, nickel, and silver, metal oxides such as antimony oxide, indium oxide, and tin oxide, and carbon materials such as carbon fiber, carbon black, and graphite. . Among these, carbon black, particularly conductive amorphous carbon, is particularly excellent in electrical conductivity, and can be given a certain degree of conductivity by simply filling a high molecular weight material to impart conductivity and controlling the amount added. Therefore, it is preferably used.

  The amount of carbon black added varies depending on the particle size of the carbon black, but is preferably in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin. If the amount is less than 1 part by mass, the volume resistance of the resin coating layer becomes high and the lubricity becomes poor. Therefore, toner develops due to charge-up and tends to cause toner fixation and fusion to the developer carrying surface. . When the amount exceeds 100 parts by mass, the volume resistance of the resin coating layer becomes low and the carbon blacks easily aggregate with each other, causing development bias leakage, insufficient toner charge amount, and reduction in strength of the resin coating layer. In some cases, non-uniform charging occurs and developability deteriorates.

  Carbon black preferably has a primary particle diameter of 10 to 100 nm. When the primary particle size is less than 10 nm, the cohesiveness between the conductive fine particles increases, and the viscosity of the paint obtained by dispersing with the coating resin increases, so that the dispersion of the conductive fine particles in the paint becomes non-uniform. There is. When the primary particle diameter exceeds 100 nm, a leakage of development bias may occur with large particles of conductive fine particles as nuclei in the resin coating layer.

  In the resin coating layer constituting the developer carrying member of the present invention, in order to adjust the surface roughness of the coating portion, particularly Rpk, to a desired value, the unevenness imparting particles are dispersed in the resin coating layer together with the conductive fine particles. It is preferable.

  The unevenness imparting particles preferably have a volume average particle diameter of 1 to 10 μm, and more preferably 2 to 6 μm. By controlling the volume average particle size of the unevenness imparting particles within the above range, desired Rz and Rpk can be obtained, and the toner coat layer on the sleeve can be made more uniform. Furthermore, even when the S-D distance is short and the electric field strength is high as in the present invention, there is no leakage of the developing bias starting from the convex shape on the surface, and the occurrence of image defects can be suppressed.

True density of unevenness imparting particles is preferably 3 g / cm ³ or less, more preferably 2.7 g / cm ³ or less, further preferably 0.9~2.3g / cm ^3. When the true density of the unevenness-imparting particles exceeds ³ g / cm ³ , the dispersibility of the unevenness-imparting particles in the resin coating layer becomes insufficient, so that it becomes difficult to impart uniform roughness to the resin coating layer surface. In some cases, the toner is uniformly charged and the strength of the resin coating layer is insufficient. Even when the true density of the unevenness imparting particles is smaller than 0.9 g / cm ³ , the dispersibility of the unevenness imparting particles in the resin coating layer may be insufficient.

  The shape of the unevenness imparting particles is preferably spherical. Spherical means a particle having a major axis / minor axis ratio of about 1.0 to 1.5 in the projected particle image, and particles having a major axis / minor axis ratio of 1.0 to 1.2 are used. It is preferable. When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the dispersibility of the spherical particles in the resin coating layer may be deteriorated or the surface roughness of the resin coating layer may be uneven.

  Known spherical particles can be used as the spherical particles. For example, a high-resistance material such as spherical resin particles is preferably used in order to improve leakage resistance.

  As the spherical resin particles, for example, those obtained by suspension polymerization, dispersion polymerization or the like can be used. Spherical resin particles can be suitably used because they can impart a suitable surface roughness to the resin coating layer with a smaller addition amount, and furthermore, the surface shape of the resin coating layer can be easily made uniform.

  Examples of the spherical resin particle materials include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenolic resin particles, and polyurethane. Resin particles, styrene resin particles, benzoguanamine particles, and the like. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.

In addition, an inorganic substance may be attached to the surface of the spherical resin particles, or may be fixed. Examples of inorganic substances include SiO ₂ , SrTiO ₃ , CeO ₂ , CrO, Ai ₂ O ₃ , ZnO, MgO and other oxides, Si ₃ N _{4 and} other nitrides, SiC and other carbides, CaSO ₄ , BaSO ₄ and CaCO _3. And carbides or carbonates thereof. Such an inorganic substance may be used after being treated with a coupling agent.

  The inorganic substance treated with the coupling agent can be preferably used particularly for the purpose of improving the adhesion between the spherical particles and the coating resin, or for imparting hydrophobicity to the spherical particles.

  Examples of such a coupling agent include a silane coupling agent, a titanium coupling agent, and a zircoaluminate coupling agent. More specifically, for example, as a silane coupling agent, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, Benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyl Diethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltet Lamethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethyl containing 2 to 12 siloxane units per molecule, each containing a hydroxyl group bonded to one silicon atom at each terminal unit Polysiloxane etc. are mentioned.

  Dispersion in the resin coating layer, uniformity of the coating layer surface, stain resistance of the coating layer, charge imparting property to the toner, Abrasion resistance and the like can be improved.

  In order to adjust the charging property of the developer carrying member, a charge control agent may be contained in the resin coating layer. In that case, it is preferable that content of a charge control agent shall be 1 mass part-100 mass parts with respect to 100 mass parts of coating resin. If the amount is less than 1 part by mass, the effect of charge control by addition is not observed. If the amount exceeds 100 parts by mass, dispersion failure occurs in the resin coating layer, and the strength of the coating tends to decrease.

  Examples of charge control agents include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and the like. Onium salts such as phosphonium salts and their lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide) Etc.), metal salts of higher fatty acids; diorganotin oxides such as butyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; diorgana such as thibutyltin borate, dioctyltin borate, dicyclohexyltin borate Suzuboreto like; guanidines, imidazole compounds.

  Among these charge control agents, when a negative toner having a high degree of spheroidization is used, it is preferable to contain a quaternary ammonium salt compound in the resin coating layer from the viewpoint of dispersibility.

  In addition, the quaternary ammonium salt compound preferably does not have ionic conductivity. When an ion conductive material is used, the water absorption property of the resin coating layer tends to be high, particularly under high temperature and high humidity, and the charge imparting property to the toner may be lowered and the developability may be deteriorated.

  Furthermore, it is more preferable that the resin coating layer contains a quaternary ammonium salt compound that is positively charged with respect to iron powder as a charge control agent in terms of improving the good charge imparting property to the toner of the present invention. . At this time, the resin coating layer contains a resin having at least one of an amino group, ═NH group, and —NH— bond in the resin structure, so that the negative toner having a high sphericity used in the present invention can be obtained. It is further preferable from the viewpoint of good charge imparting properties.

  By providing on the developer carrier a resin coating layer formed by combining the quaternary ammonium salt compound and the resin having the specific structure on the developer carrier, the negative toner having a high sphericity can be obtained. It works in the direction of preventing excessive charging and can control the application of triboelectric charge to the negative toner. As a result, it is possible to prevent the toner from being charged up on the developer carrying member, to prevent toner fusion from occurring on the surface of the resin coating layer, and to maintain uniform charging stability of the toner. As a result, it is possible to provide a high-definition image having environmental stability and long-term stability.

  Although the reason is not clear, a quaternary ammonium salt compound that is itself positively charged with respect to iron powder, when added, has at least one of an amino group, ═NH or —NH— in the structure. It is considered that the binder resin composition itself having the above-mentioned compound has a negative chargeability because it is uniformly dispersed in the resin containing the two and further taken into the structure of the resin when the coating is formed. . Therefore, for negatively chargeable toners, the toner acts in a direction that prevents the toner from having an excessive negative charge amount, and as a result, the negative charge amount can be appropriately controlled.

  As the quaternary ammonium salt compound, any compound may be used as long as it has a positive chargeability with respect to iron powder. For example, a compound represented by Formula 1 can be given.

(Wherein R ₁ , R ₂ , R ₃ and R ₄ represent an alkyl group which may have a substituent, an aryl group which may have a substituent, and an aralkyl group, respectively, R _{1 to} R ₄ may be the same or different, and X ⁻ represents an anion of an acid.)
As specific examples of the acid ion of X ^{− in} formula 1, an organic sulfate ion, an organic sulfonate ion, an organic phosphate ion, a molybdate ion, a tungstate ion, a heteropolyacid containing a molybdenum atom, or a tungsten atom is preferably used. It is done.

  Specific examples of the quaternary ammonium salt compound that is preferably used in the present invention and is positively charged with respect to iron powder are shown in the following formulas 2, 3, 4, and 5. Of course, the present invention is not limited to these examples.

  In addition, as a preferred resin containing at least one of an amino group, = NH or -NH- in the structure in combination with a quaternary ammonium salt, a phenol resin produced using a nitrogen-containing compound as a catalyst in the production process , Polyamide resin, epoxy resin using polyamide as a curing agent, urethane resin, or a copolymer partially containing these resins. The quaternary ammonium salt compound is easily taken into the structure of the coating resin when the mixture with the coating resin is formed.

  Phenol resins that can be suitably used in combination with a quaternary ammonium salt include nitrogen-containing compounds used as catalysts in the production process. Examples of acidic catalysts include ammonium sulfate, ammonium phosphate, ammonium sulfamate, and ammonium carbonate. , Ammonium salts such as ammonium acetate and ammonium maleate or amine salts. Basic catalysts include ammonia or dimethylamine, diethylamine, diisopropylamine, diisobutylamine, diamylamine, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, dimethylbenzylamine, diethylbenzylamine, dimethylaniline, diethylaniline. N, N-di-n-butylaniline, N, N-diamilaniline, N, N-di-t-amylaniline, N-methylethanolamine, N-ethylethanolamine, diethanolamine, triethanolamine, dimethylethanolamine , Diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropanolamine, ethylenediamine, hexamethyl Amino compounds such as tetramine; pyridines such as pyridine, α-picoline, β-picoline, γ-picoline, 2,4-lutidine, 2,6-lutidine, and derivatives thereof; quinoline compounds, imidazole, 2-methylimidazole, 2, Examples include nitrogen-containing heterocyclic compounds such as 4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, imidazole such as 2-heptadecylimidazole, and derivatives thereof. It is done.

  The polyamide resin constituting the coating resin is, for example, nylon 6, 66, 610, 11, 12, 9, 13, Q2 nylon, or a nylon copolymer containing these as a main component, or N -Alkyl-modified nylon, N-alkoxylalkyl-modified nylon and the like can be suitably used. Furthermore, any resin containing a polyamide resin such as various resins modified with polyamide such as a polyamide-modified phenol resin or an epoxy resin using a polyamide resin as a curing agent may be used. Can be used.

  Moreover, as a urethane resin which comprises the coating resin suitably used in combination with a quaternary ammonium salt, any resin can be used as long as it contains a urethane bond. This urethane bond is obtained by polymerization addition reaction of polyisocyanate and polyol. Polyisocyanates that are the main raw materials for this polyurethane resin include TDI (tolylene diisocyanate), pure MDI (diphenylmethane diisocyanate), polymeric MDI (polymethylene polyphenyl polyisocyanate), TODI (tolidine diisocyanate), NDI (naphthalene diisocyanate), and the like. Aromatic polyisocyanates such as: HMDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), XDI (xylylene diisocyanate), hydrogenated XDI (hydrogenated xylylene diisocyanate), aliphatic MDI (dicyclohexylmethane diisocyanate), etc. And polyisocyanates.

  Polyols that are the main raw materials for this polyurethane resin include polyether polyols such as PPG (polyoxypropylene glycol), polymer polyol, polytetramethylene glycol (PTMG); polyester polyols such as adipate, polycaprolactone, and polycarbonate polyol. Polyether modified polyols such as PHD polyol and polyether ester polyol; other epoxy-modified polyols; partially saponified polyols of ethylene-vinyl acetate copolymer (saponified EVA); flame retardant polyols and the like.

  The base of the developer carrying member includes a cylindrical member, a columnar member, a belt-like member, etc., but in a developing method that does not contact the drum, a rigid cylindrical tube or a solid rod such as metal is preferably used. It is done. As such a substrate, a non-magnetic metal or alloy such as aluminum, stainless steel, or brass, which is molded into a cylindrical shape or a cylindrical shape, and subjected to polishing, grinding, or the like, is preferably used. These substrates are used after being molded or processed with high accuracy in order to improve the uniformity of the image. For example, the straightness in the longitudinal direction is preferably 30 μm or less, or 20 μm or less, more preferably 10 μm or less, and the gap between the sleeve and the photosensitive drum is swayed, for example, abuts against a vertical surface through a uniform spacer. When the sleeve is rotated, the fluctuation of the gap with the vertical surface is preferably 30 μm or less, 20 μm or less, and more preferably 10 μm or less. Aluminum is preferably used because of material cost and ease of processing.

  The base member may be a cylindrical member having a layer structure including a rubber or elastomer such as urethane, EPDM, or silicon on a metal core.

  Further, blasting may be performed on the surface of the developer carrying member in order to improve developer transportability. Specifically, a blast material such as spherical glass beads is used and sprayed from the blast nozzle to the surface of the substrate at a predetermined pressure for a predetermined time to form a number of depressions on the surface of the developer carrying member.

  The resin coating layer can be formed, for example, by dispersing and mixing each component in a solvent to form a paint and coating the substrate. For dispersion mixing of each component, a known dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, a pearl mill or the like can be suitably used. Moreover, as a coating method, well-known methods, such as a dipping method, a spray method, and a roll coat method, are applicable.

  Next, the developing device used in the developing method of the present invention will be described.

  FIG. 6 is a schematic diagram showing an example of the configuration of the developing device used in the present invention. In FIG. 6, the electrophotographic photosensitive drum 1 as an electrostatic latent image carrier that carries an electrostatic latent image formed by a known process is rotated in the arrow B direction. A developer carrier 8 as a developer carrier is composed of a metal cylindrical tube (base) 6 and a resin coating layer 7 formed on the surface thereof. A columnar member can be used instead of the metal cylindrical tube. In the hopper 3 which is a developer container, a stirring blade 10 for stirring the nonmagnetic one-component developer 4 is provided.

  A developer supply / peeling member 11 for supplying the developer 4 to the developer carrier 8 and stripping off the developer 4 existing on the surface of the developer carrier 8 after development is provided on the developer carrier 8. It is in contact. The supply / peeling roller 11, which is a developer supply / peeling member, rotates in the same direction as the developer carrier 8, so that the surface of the supply / peeling roller 11 faces the surface of the developer carrier 8 in the counter direction. Will move. As a result, the one-component nonmagnetic developer having the nonmagnetic toner supplied from the hopper 3 is supplied to the developer carrier 8. When the developer carrier 8 carries the one-component developer 4 and rotates in the direction of arrow A, the non-magnetic one-component developer is developed in the development region D that is the region facing the developer carrier 8 on the surface of the photosensitive drum 1. 4 is conveyed. The developer layer thickness of the one-component developer carried on the developer carrying member 8 is defined by the developer layer thickness regulating member 2 that is pressed against the surface of the developer carrying member 8 via the developer layer. The nonmagnetic one-component developer 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction with the developer carrier 8.

  The thickness of the thin layer of the non-magnetic one-component developer 4 formed on the developer carrier 8 is thinner than the minimum gap in the development area D between the developer carrier 8 and the photosensitive drum 1 in the development portion. It is preferable. A developing bias voltage is applied to the developer carrier 8 by a developing bias power source 9 in order to cause the one-component nonmagnetic developer 4 having nonmagnetic toner carried thereon to fly. In the present invention, in order to increase the density of the developed image or to improve the gradation, an alternating bias voltage is applied to the developer carrier 8 to form an oscillating electric field whose direction is alternately reversed in the developing portion. ing. In this case, it is preferable to apply to the developer carrier 8 an alternating bias voltage in which a DC voltage component having a value between the potential of the image portion and the background portion is superimposed.

  As a waveform of the AC voltage, a sine wave, a rectangular wave, a triangular wave or the like can be used as appropriate. Further, it may be a pulse wave formed by periodically turning on / off a DC power source. In this way, a bias that periodically changes the voltage value can be used as the waveform of the AC voltage.

  The S-D distance, which is the minimum gap between the developer carrying member 8 and the photosensitive drum 1 in the developing unit of the developing device, is preferably 100 μm to 220 μm, and more preferably 130 μm to 200 μm.

  By controlling the S-D distance within this range, development bias leakage can be suppressed, toner followability to the latent image on the photoreceptor can be improved, and high image quality can be obtained.

Further, in the developing device used in the present invention, the maximum electric field strength between S and D is preferably controlled to 6.0 × 10 ^{6 to} 2.0 × 10 ⁷ V / m, and 7.5 × 10 ^6. More preferably, it is controlled to ˜1.5 × 10 ⁷ V / m. When the maximum electric field strength is less than 5.0 × 10 ⁶ V / m, the reciprocating motion of the toner cannot be suppressed and the scattering / fogging may be deteriorated. Further, since the developing power is small, an image having a low image density is likely to be obtained. Further, when the maximum electric field strength exceeds 1.5 × 10 ⁷ V / m, it is easy to cause a decrease in resolution due to an excessive development force and a decrease in image quality due to an increase in fog. Image defects due to leakage to the developer carrier are likely to occur.

  The developer supply / peeling member 11 is preferably an elastic roller member such as resin, rubber, or sponge. As the stripping member, a belt member or a brush member can be used instead of the elastic roller. The developer that has not been transferred to the photosensitive member 1 is once peeled off from the sleeve surface by the developer supply / peeling member 11, thereby preventing the generation of a stationary developer on the sleeve and uniform charging of the developer. Turn into.

  When the supply / peeling roller 11 made of an elastic roller is used as the developer supply / peeling member, the circumferential speed of the supply / peeling roller 11 is such that the surface of the roller 13 is in the counter direction with respect to the developer carrier 8. When rotating, 20% to 120% is preferable and 30% to 100% is more preferable with respect to the peripheral speed of 100% of the developer carrier 8.

  When the peripheral speed of the supply / peeling roller 11 is less than 20%, the supply of the developer is insufficient, the followability of the solid image may be reduced, and a ghost image may be caused. The peripheral speed is 120%. Exceeding the above range, the developer supply amount increases, which may cause fogging due to poor regulation of the developer layer thickness or insufficient charge amount, and more easily damage the toner. It tends to cause fusion.

  When the rotation direction on the surface of the supply / peeling roller 11 is the same (forward) direction as the rotation direction of the surface of the developer carrier, the peripheral speed of the supply roller is relative to the sleeve peripheral speed in terms of toner supply amount. 100% to 300% is preferable, and 101% to 200% is more preferable. The rotation direction on the surface of the supply / peeling roller 11 is more preferably rotated in the direction of rotation on the surface of the developer carrying member and the counter direction from the viewpoint of stripping property and supply property.

  The penetration amount of the developer supply / peeling member 11 with respect to the developer carrier 8 is preferably 0.5 mm to 2.5 mm from the viewpoint of developer supply and strippability. When the amount of penetration of the developer supply / peeling member 11 is less than 0.5 mm, a ghost is likely to occur due to insufficient peeling, and when the penetration amount exceeds 2.5 mm, the toner damage increases. The toner is likely to cause fusing and fogging due to toner deterioration.

  In the developing device of FIG. 6, as a member for regulating the layer thickness of the non-magnetic one-component developer 4 on the developer carrier 8, a material having rubber elasticity such as urethane rubber or silicone rubber, or phosphor bronze or stainless copper is used. The elastic regulating blade 11 made of such a material having metal elasticity is used.

  A thinner developer layer can be formed on the developer carrier 8 by pressing the elastic regulation blade 11 against the developer carrier 8 in a posture opposite to the rotation direction of the developer carrier 8. As the elastic regulating blade 11, a polyamide elastomer (PAE) is pasted on the surface of a phosphor bronze plate, which can obtain a stable pressurizing force, particularly for a stable regulating force and a stable (negative) chargeability to the toner. It is preferable to use a structure. Examples of the polyamide elastomer (PAE) include a copolymer of polyamide and polyether.

  The contact pressure of the developer layer thickness regulating member 2 with respect to the developer carrier 8 is a linear pressure of 5 to 50 g / cm to stabilize the developer regulation and to suitably adjust the developer layer thickness. It is preferable at the point which can do.

  When the contact pressure of the developer layer thickness regulating member 2 is less than 5 g / cm of linear pressure, the regulation of the developer becomes weak, causing fogging and toner leakage, and when the linear pressure exceeds 50 g / cm. The damage to the toner is increased, and this tends to cause toner deterioration and fusion to the sleeve and blade.

Next, a method for measuring various physical properties according to the present invention will be described below.
(1) Ten-point average roughness Rz, coefficient of variation, initial wear height Rpk
Using a surf coder SE-3500 manufactured by Kosaka Laboratory, 100 points were measured at a cutoff of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / s, and the average value was taken.

  Further, the coefficient of variation of Rz at this time was calculated by first obtaining the standard deviation when measuring 100 points of the sample and dividing the value by the average value. The ten-point average roughness Rz is obtained from the roughness curve shown in FIG. A reference length l is extracted in the direction of the average line of the obtained roughness curve, and from the average line of this extracted part, the average value of the absolute values of the altitude (Yp) of the highest peak from the highest peak to the fifth peak is obtained. A value obtained by summing up the average value of the absolute values of the altitudes (Yv) of the bottom valley from the lowest valley bottom to the fifth is defined as Rz.

  The initial wear height Rpk is a characteristic value obtained from the surface roughness curve, and is obtained as follows. First, a load curve (BAC) is obtained from the obtained roughness curve. FIG. 2 schematically shows the relationship between the roughness curve and the load curve (BAC). In FIG. 2, b1, b2, bi, and bn represent the respective cutting lengths obtained when the roughness curve is cut at a cutting level C parallel to the peak line of the roughness curve, and C represents the roughness curve. It represents the cutting level from the peak, m represents the average line of the roughness curve, L represents the reference length, and tp represents the load length ratio (%) obtained from the formula in FIG.

Next, as shown in FIG. 3, a straight line having the smallest inclination is selected from the straight lines passing through the two points A and B where the difference in load length ratio is 40% on the obtained load curve (BAC). A point where this straight line intersects the axis with a load length rate of 0% is defined as a point C. Further, an intersection between the cutting height level passing through the point C and the load curve is defined as a point H, and an intersection between the load curve and an axis having a load length rate of 0% is defined as a point I. Then, a point J at which the area surrounded by the line segment CH, the curve HI, and the line segment IC is equal to the area of the triangle CHJ is obtained on the axis with a load length ratio of 0%. Let Rpk be the distance between this point C and point J.
(2) Measurement of volume resistance of resin coating layer A high resistivity of Mitsubishi Chemical Corporation, which is formed on a 200 μm thick aluminum sheet and has a thickness of 20 to 25 μm and conforms to JIS K6911. The total was measured using Hirester UP (MCP-HT450). As the measurement conditions, a probe UR-100 was used, and the volume resistance was examined with an applied voltage of 10 V and a measurement time of 10 seconds. The measurement environment was 20 to 25 ° C. and 50 to 60% RH.

A conductive resin coating layer of 7 to 20 μm is formed on a 100 μm thick PET sheet, and a volume resistance value is measured using a 4-terminal probe with a resistivity meter Loresta AP or Hiresta IP (both manufactured by Mitsubishi Chemical). Was measured. The measurement environment was 20 to 25 ° C. and 50 to 60% RH.
(3) Measurement of particle diameter of conductive fine particles such as carbon black The particle diameter of the conductive fine particles was measured using an electron microscope. The shooting magnification was set to 60,000 times, but when it was difficult, the photograph was enlarged and printed so as to be 60,000 times after shooting at a low magnification. Measure the primary particle size on the photo. At this time, the major axis and the minor axis are measured, and the average value is defined as the particle size. This was measured for 100 samples, and the 50% value was taken as the primary particle size.

Example 1
EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(1) Production of developer carrier (developer carrier 1 production)
Resol type phenol resin: 200 parts (using ammonia catalyst, containing 50% methanol)
Carbon black: 17 parts (primary particle size 30 nm)
Uneven particles 2: 5 parts Methanol: 55 parts The above materials were dispersed in a sand mill using glass beads. In the dispersion method, 17 parts by mass of carbon black and 30 parts by mass of methanol are added to 30 parts by mass of a resol-type phenol resin solution (containing 50% methanol) prepared using ammonia as a catalyst, and glass beads having a diameter of 1 mm are added as media particles. In addition, it was dispersed in a horizontal sand mill to obtain a coating intermediate. 170 parts by mass of the remaining resol type phenolic resin solution (containing 50% methanol) and 25 parts by mass of methanol and 5 parts by mass of the uneven particles 2 shown in Table 2 were added to this coating intermediate, and glass beads with a diameter of 1 mm were used as media particles. In addition, it was dispersed in a vertical sand mill to obtain a coating liquid 2.

  The aluminum substrate 3 ground to an outer diameter of 16 mmφ, a ten-point average roughness Rz = 3.0 μm, and an initial wear height Rpk = 0.37 μm shown in Table 1 by an air spray method using the coating liquid 2. A resin coating layer was formed, and subsequently heated at 150 ° C. for 30 minutes in a hot air drying furnace to cure the resin coating layer, thereby producing a developer carrier 1.

  The developer carrier 1 had a ten-point average roughness Rz = 4.5 μm, a coefficient of variation of Rz of 7.0%, and an initial wear height Rpk = 0.8 μm.

(Examples 2-14 and Comparative Examples 1-7)
(Manufacture of developer carriers 2-14 and comparative carriers 1-7)
Using the developer carrying member production method shown in Example 1, carriers 2 to 14 used in Examples 2 to 14 and carriers 15 to 21 used in Comparative Examples 1 to 7 were produced. Table 1 shows the substrate, uneven particles, and coating solution used, Table 2 shows uneven particles, and Table 3 shows the coating solution.

(2) Production of developer A toner was produced by a polymerization method according to the following procedure.

  3 parts of tricalcium phosphate was added to 900 g of ion-exchanged water heated to 60 ° C., and stirred at 10,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare an aqueous medium. Further, the following formulation was put into a homogenizer (manufactured by Nippon Seiki Co., Ltd.), heated to 60 ° C., and then stirred at 9000 rpm to dissolve and disperse.

Styrene: 150 parts n-butyl acrylate: 50 parts C.I. I. Pigment Blue 15: 3: 18 parts Aluminum salicylate compound: 2 parts (Bontron E-88: manufactured by Orient Chemical Co., Ltd.)
Polyester resin: 15 parts (polycondensate of propylene oxide modified bisphenol A and isophthalic acid, Tg = 65 ° C., Mw = 10000, Mn = 6000)
-Stearyl stearate wax (DSC main peak 60 ° C): 30 parts-Divinylbenzene: 0.6 parts In this, 5 parts by mass of 2,2'-azobis (2,4-dimethylvaleronitrile) polymerization initiator was dissolved. A polymerizable monomer composition was prepared. The polymerizable monomer composition was put into the aqueous medium, and granulated by stirring at 8000 rpm using a TK homomixer at 60 ° C. in a nitrogen atmosphere. Then, the temperature was raised to 70 ° C. over 2 hours while stirring by transferring to a propeller type stirring device, and further 4 hours later, the temperature was raised to 80 ° C. at a temperature raising rate of 40 ° C./Hr, and the reaction was carried out at 80 for 5 hours. To produce polymer particles. After completion of the polymerization reaction, the slurry containing the particles is cooled, washed with an amount of water 10 times that of the slurry, filtered and dried, and then the particle size is adjusted by classification to form base toner particles (weight average particle size of 6. 8 μm and an average circularity of 0.981) were obtained.

  With respect to 100 parts by mass of the toner particles, 1.0 part by mass of hydrophobic silica fine powder surface-treated with hexamethylene disilazane (average primary particle diameter 7 nm), 0.15 part by mass of rutile titanium oxide fine powder (average primary) Non-magnetic one-component developer used in the present invention by dry-mixing 0.5 part by mass of rutile-type titanium oxide fine powder (average primary particle diameter 200 nm) with a Henschel mixer (Mitsui Mining Co., Ltd.) for 5 minutes. As a toner.

(3) Examples <Examples 1 to 14, Comparative Examples 1 to 7>
Using a modified LBP-2510 (manufactured by Canon Inc.) as an evaluation machine as follows, the prepared developer carrier is mounted, and an EP-85 cyan cartridge filled with the prepared toner is mounted. The following evaluation was performed.

  First, as a modification of the developing device configuration of the evaluation machine, the charging auxiliary roller mounted on the developer carrying member is removed from the EP-85 cyan cartridge used in LBP-2510, and the toner prepared above is put on the cyan cartridge. Filling and further incorporating the developer carrier prepared above was carried out. Further, the diameter of the roller on the left and right of the developer carrying member was changed to a larger one, and the SD distance between the toner carrying member and the photosensitive member was set to 160 μm. Next, the modified EP-85 cyan cartridge was installed in the cyan station, and dummy cartridges were installed in the other stations, and a single color evaluation was performed.

As development conditions, the dark portion potential (Vd) of the non-image portion of the photoreceptor was set to −500 V, and the bright potential (VI) of the image on which the electrostatic latent image was formed was set to −100 V. Further, the developer carrier is subjected to jumping development using a DC bias of −250 V as a developing bias and an AC bias composed of a rectangular wave with a frequency of 3 kHz and a voltage between peaks (Vpp) of 1.5 kV. It was. At this time, the maximum electric field strength was 9.38 × 10 ⁶ V / m.

  The evaluation environment includes a low temperature / low humidity environment (L / L) of 15 ° C./10% RH, a normal temperature / normal humidity environment (N / N) of 23 ° C./60% RH, and a high temperature of 30 ° C./85% RH. / It performed about three environments under high-humidity environment (H / H), and all printed out images of 2% printing ratio up to 5000 sheets.

Evaluation 1 Image density Using a normal copying machine (75 g / m ² ) transfer material, a solid image was output at the initial stage and at the end of durability evaluation in an image output test, and the density was measured. . The image density was measured by using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an image of a white background portion having a document density of 0.00.
A: Very good 1.40 or more B: Good 1.35 or more, less than 1.40 C: No practical problem 1.00 or more, less than 1.35 D: Practical problem Less than 1.00
Evaluation 2 The fog density (%) was calculated from the difference between the whiteness of the white portion of the printout image and the whiteness of the transfer paper measured by the fog “REFECTRECTER MODEL TC-6DS” (manufactured by Tokyo Denshoku), and durability evaluation Image fog at the end was evaluated. In the case of cyan, an amber light filter was used as the filter.
A: Very good Less than 0.5% B: Good 0.5% to less than 1.0% C: No practical problem 1.0% to less than 1.5% D: Practical problem 1.5 %more than
Evaluation 3 An image in which a solid white image followed by a solid white image of 30 mm × 20 mm in sweeping length × width was output, and the sweeping portion was numerically evaluated by the following method.

  FIG. 4 shows an example of outputting the image pattern. The image output as shown in FIG. 4 is taken into the PC by the image scanner system, and the image density is converted into numerical data of 0 to 255. FIG. 5 shows an example of a density distribution with respect to the Y axis of a sample image captured by the image scanner system.

In FIG. 5, a region where the density is higher in the range of Yb to Yc than the range of Ya to Yb is a rushing region. The hatched portion in FIG. 5 is the integrated value of the hit density, and the change in density per millimeter was used as the hit value. In the case of the contact data shown in FIG. 5, the value of the contact area Yb-Yc is 4 (mm), and the integrated value of the contact density (shaded portion in the figure) is 160 (dig). Therefore, the threshold value is 160/4 = 40 (dig / mm).
A: Very good Sweep value less than 10 B: Good Sweep value 10 or more and less than 15 C: No problem in practical use Sweep value 15 or more and less than 20 D: Practical problem Sweep value 20 or more and less than 25 E : Poor sweep value 25 or more Table 4 shows the results of the above three evaluation results. In the present invention, the rank C or higher is within a practical allowable range.

<Examples 15 to 19 and Comparative Examples 8 to 11>
In the above evaluation, when remodeling LBP-2510, several rollers with different radii are prepared so that the distance between S and D can be changed in the range of 100 to 220 μm, and further, the Vpp set value is changed to change the electrostatic capacity of the developer carrier. EP-85 in which the carriers 1, 6, 7, 10, 12, 18, 19, 20, and 21 shown in Table 5 were installed in the same manner except that the maximum electric field strength with the latent image carrier was changed. The following leakage resistance was evaluated using the cartridge.

Evaluation 4 Under a normal temperature / humidity environment (N / N) of leak-resistant atmospheric pressure 101 kPa and 23 ° C./60% RH, the image is drawn while increasing the voltage (Vpp) between the peaks of the AC bias. The value of Vpp when the image was disturbed was taken as the leakage limit voltage Vm and used as an index of leakage resistance.

  At this time, the leakage electric field voltage Vm was measured by changing the distance between S and D for several developer carriers, and the horizontal axis shows the distance between SD and the vertical axis shows the leakage limit voltage Vm. 7.

In FIG. 7, Vpp (V) = electric field strength (V / m) × S-D distance (μm), and the electric field strength range (6.0 × 10 ^{6 to} 2.0 × 10) in the developing method of the present invention. ⁷ V / m), two straight lines representing the maximum and minimum values of Vpp at each SD distance are shown. As the leakage limit voltage Vm is higher, the leakage resistance is better. However, as described above, when the electric field strength is too large, the developing power is too large, and image defects such as a decrease in resolution and fogging occur. On the other hand, when the electric field strength is too low, the image density is lowered because the developing power is small. That is, in FIG. 7, when the S-D distance is changed, it is preferable that the leakage limit voltage Vm be between the straight lines of the electric field strengths Min and Max in a wide range of S-D distances.

  In other words, in FIG. 7, it is preferable that the leakage limit voltage Vm is between the straight lines of the electric field strengths Min and Max in a wide range when the distance between S and D is changed.

Schematic explaining ten-point average roughness Rz. Schematic explaining the relationship between a roughness curve and a load curve. Schematic explaining the relationship of initial wear height Rpk. The figure which shows an example of a sweeping image output. An example of the density distribution with respect to the Y axis of a sweeping image. FIG. 2 is a schematic diagram showing an embodiment of a developing device of the present invention when a nonmagnetic one-component developer is used. The figure which measures the leak limit voltage Vm in the distance between SD, and shows the distance between SD on a horizontal axis, and the leak limit voltage Vm on a vertical axis | shaft.

Explanation of symbols

1 Electrophotographic photosensitive drum (electrostatic latent image carrier)
2 Elasticity regulating blade (developer layer thickness regulating member)
3 Hopper (developer container)
4 Developer 6 Metal cylindrical tube (base)
7 Resin coating layer 8 Developer carrier 9 Development bias power supply (bias means)
DESCRIPTION OF SYMBOLS 10 Stirring blade 11 Developer supply / peeling member A Developer carrier rotating direction B Photosensitive drum rotating direction D Development area

Claims (16)

The development of the electrostatic latent image carrier in which the developer carried on the surface of the developer carrier is placed facing the developer carrier with a predetermined distance (distance between S and D). An alternating voltage is applied to the developer carrier in the development region formed at the closest part to the developer carrier, and the developer carried on the surface of the developer carrier is applied to the electrostatic latent image carrier. A developing method for transporting and developing the electrostatic latent image carried on the electrostatic latent image carrier,
(1) The maximum electric field strength between the developer carrier and the electrostatic latent image carrier is 6.0 × 10 ^{6 to} 2.0 × 10 ⁷ V / m,
(2) The developer carrying member includes at least a substrate and a resin coating layer containing conductive fine particles on the surface of the substrate, and the resin coating layer of the developer carrying member facing the electrostatic latent image carrier. The 10-point average roughness Rz of the non-coated portion where no coating is formed is 1.5 to 5.0 μm, the initial wear height Rpk is 0.1 to 0.6 μm, and the electrostatic latent image carrier The ten-point average roughness Rz of the coating portion where the resin coating layer of the developer carrying member facing is 2.0 to 9.0 μm, and the initial wear height Rpk is 0.3 to 2.5 μm. A developing method characterized in that the resin coating layer has a volume resistance of 10 ⁵ to 10 ¹¹ Ω · cm.   The developing method according to claim 1, wherein the distance between the developer carrier and the electrostatic latent image carrier is 100 to 220 μm.   The developing method according to claim 1, wherein the distance between the developer carrier and the electrostatic latent image carrier is 130 to 200 μm. 4. The maximum electric field strength between the developer carrying member and the electrostatic latent image carrying member is 7.5 × 10 ^{6 to} 1.5 × 10 ⁷ V / m. 5. The developing method according to any one of the above.   The developing method according to claim 1, wherein the resin coating layer has a thickness of 12 to 50 μm.   The developing method according to claim 1, wherein the resin coating layer has a thickness of 17 to 50 μm.   The developing method according to claim 1, wherein the ten-point average roughness Rz of the resin coating layer has a variation coefficient of 11% or less.   The ten-point average roughness Rz of the uncoated portion is 2.0 to 4.0 µm, and the initial wear height Rpk is 0.2 to 0.5 µm. The developing method described in 1.   The ten-point average roughness Rz of the coat portion is 3.0 to 7.0 µm, and the initial wear height Rpk is 0.4 to 1.5 µm. The developing method as described. A developer carrying member for carrying the developer in layers, an electrostatic latent image carrying member disposed to face the development carrying member with a gap, and a power source for applying at least an alternating voltage to the developing carrier. Have
The developer carrier has at least a substrate and a resin coating layer containing conductive fine particles on the surface of the substrate, and the resin coating layer of the developer carrier facing the electrostatic latent image carrier is formed. The uncoated portion has a ten-point average roughness Rz of 1.5 to 5.0 μm, an initial wear height Rpk of 0.1 to 0.6 μm, and faces the electrostatic latent image carrier. The ten-point average roughness Rz of the coat portion on which the resin coating layer of the developer carrying member is formed is 2.0 to 9.0 μm, the initial wear height Rpk is 0.3 to 2.5 μm, A developer carrier, wherein the resin coating layer has a volume resistance of 10 ⁵ to 10 ¹¹ Ω · cm. The maximum electric field strength between the developer carrying member and the electrostatic latent image carrying member is 6.0 × 10 ^{6 to} 2.0 × 10 ⁷ V / m. Development carrier.   The developer carrying member according to claim 10 or 11, wherein the resin coating layer has a thickness of 12 to 50 µm.   13. The developer carrying member according to claim 10, wherein the resin coating layer has a thickness of 17 to 50 μm.   The developer carrying member according to any one of claims 10 to 13, wherein a coefficient of variation of the ten-point average roughness Rz of the resin coating layer is 11% or less.   The ten-point average roughness Rz of an uncoated portion of the developer carrying member is 2.0 to 4.0 µm, and an initial wear height Rpk is 0.2 to 0.5 µm. 15. The developer carrying member according to any one of 1 to 14.   The ten-point average roughness Rz of the coat part is 3.0 to 7.0 μm, and the initial wear height Rpk is 0.4 to 1.5 μm. The developer carrying member as described.

Images