JP2017167508A - Image forming method, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method with which the occurrence of negative afterimage can be effectively suppressed.SOLUTION: There is provided an image forming method for forming an image by using a photoreceptor comprising at least an intermediate layer and a photosensitive layer obtained by laminating a charge generating layer and a charge transport layer on a conductive substrate, where the relationship between the ionization potential on a surface of the photoreceptor and the ionization potential of a toner satisfies the following formula (1) and following formula (2). (1) |Ip(photoreceptor surface)-Ip(toner)|≤0.18[eV], and (2) 5.45[eV]≤Ip(photoreceptor surface)≤5.53[eV].SELECTED DRAWING: None

Description

  The present invention relates to an image forming apparatus including a copying machine, a facsimile machine, a printer, and a complex machine thereof, and more particularly to an image forming method and an image forming apparatus suitable for production printing that require formation of a high quality image. In particular, the present invention relates to an image forming method, an image forming apparatus, and a process cartridge that suppress the occurrence of a negative afterimage.

  In recent years, electrophotography has been developed in the production printing market that handles output products as products for office use. The electrophotographic system does not require plate making like offset printing, and has an advantage that a required number of printed materials can be created on demand. On the other hand, high quality and homogeneity of output products are required.

  One of the problems that must be solved regarding the improvement of the image quality of output products is the suppression of negative afterimages. A negative afterimage is an image defect identified as an afterimage in a halftone image. For example, when a black character is output in a white background and a halftone image is subsequently output on the entire surface, the history of the black character portion appears on the halftone lighter than the surroundings in the photosensitive member cycle.

  Various mechanisms for generating negative afterimages are described in conventional patent documents. For example, paragraph [0025] of Japanese Patent Laid-Open No. 2013-281366 describes that a negative afterimage is generated by a history of exposure and transfer. For example, a transfer stress is stronger in an unexposed portion where a toner image does not exist on the photosensitive member at the time of transfer compared to an exposed portion in which the toner image is developed, and an image history is generated with the deviation. It is understood that a transfer stress in which the charge remaining in the photosensitive layer is biased causes a bias in the surface potential of the photoreceptor, and is manifested as an afterimage in the output image.

A number of methods have been proposed to eliminate afterimages.
For example, Patent Document 1 proposes a method that has afterimage recognition means and outputs an image for removing afterimages when afterimages are detected by repeating a large amount of image formation.
In Patent Document 2, the grid voltage of the charger, the developing voltage, the amount of light from the discharge lamp, and the like are set for each rotation of the photoconductor based on the film thickness of the photoconductor, the image formation standby time, the photoconductor temperature, the photoconductor prescription, and the production lot. Various methods have been proposed to stabilize the surface potential and keep the image density constant.
Patent Document 3 proposes a method in which a light irradiating unit is provided between a transfer unit and a cleaning unit, and a charge is removed by irradiating the photosensitive member with a discharging light.

In Patent Document 4, an electrode in contact with the surface of the photoconductor is installed on the upstream side of the charger between the transfer device and the charger, and an afterimage is formed by applying a voltage having the same polarity as the charged potential of the surface of the photoconductor. A removal method has been proposed.
Patent Document 5 discloses a method characterized in that the wavelength of light emitted from the static elimination means is set to a wavelength in the range of the half-value width of the maximum absorbance in the absorbance characteristics of the photosensitive layer or the charge generation material contained in the photosensitive layer. Has been.
Patent Document 6 discloses a method in which, in the charge removal of a predetermined single layer type photoreceptor, the wavelength λ0 of the exposure light source and the charge removal light wavelength λ1 satisfy the relationship of λ0−200 nm ≦ λ1 ≦ 780 nm. Has been.

An object of the present invention is to provide an image forming method capable of effectively suppressing the occurrence of a negative afterimage.

The above problem can be solved by the following image forming method according to the present invention as described below.
According to the present invention, the following image forming method (1) is provided.
(1) An image forming method for forming an image using a photoreceptor having at least an intermediate layer and a photosensitive layer formed by laminating a charge generation layer and a charge transport layer on a conductive support,
An image forming method, wherein a relationship between an ionization potential on the surface of the photoreceptor and an ionization potential of a toner satisfies the following formulas (1) and (2):
| Ip (photosensitive member surface) −Ip (toner) | ≦ 0.18 [eV] (1)
5.45 [eV] ≦ Ip (photosensitive member surface) ≦ 5.53 [eV] (2)
(here,
Ip (photoconductor surface) represents the ionization potential of the photoconductor surface,
Ip (toner) represents the ionization potential on the toner surface. )

  According to the image forming method of the present invention, generation of a negative afterimage can be effectively suppressed.

FIG. 1 is a diagram showing an example of measurement results of photoelectron yield spectroscopy. FIG. 2 is a schematic configuration diagram showing an example of the image forming apparatus of the present invention. FIG. 3 is a schematic configuration diagram showing another example of the image forming apparatus of the present invention. FIG. 4 is a schematic diagram showing an example of the process cartridge of the present invention.

  Hereinafter, the present invention will be described. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented.

Patent Document 1 describes that when an afterimage is detected, an image for removing the afterimage (solid image) is output, but the image formation stops during continuous output, resulting in a decrease in productivity. There is a problem that the toner consumption increases when there are frequent problems and afterimages occur frequently.
In the method described in Patent Document 2, the image forming conditions are changed for each circumference according to the creation conditions of the photoconductor and the standby state. However, there are cases where the photoconductor conditions vary widely and the afterimages cannot be removed.
In the method described in Patent Document 3, static elimination is performed by light irradiation between transfer and cleaning. However, in the case of reversal development using a negatively charged toner, many positive charges are trapped at the time of transfer. In the case of a photoreceptor, since it is a negative charge that can be neutralized by light irradiation, in that case, there is a high possibility that no effect will be seen.

In the method described in Patent Document 4, an electrode that is in contact with the photosensitive member is provided. However, it is impossible to deny the possibility that toner that could not be cleaned adheres to this portion and potential unevenness occurs.
Even with the static elimination methods disclosed in Patent Documents 5 and 6, it is difficult to remove residual charges in the deep layer of the photosensitive layer. In particular, when the photosensitive layer is made thick or when the image forming speed is increased, the charge generated by the static elimination light is less likely to move due to the residual charge in the deep layer of the photosensitive layer. A problem has been pointed out that the charging potential becomes non-uniform.

  As described above, the conventional technique for suppressing the negative afterimage from the improvement of the image forming process cannot be denied that the effect is insufficient or the productivity is impaired. It is desirable to give the photoconductor itself resistance to negative afterimages.

The photoreceptor in the present invention is a photoreceptor having at least an intermediate layer and a photosensitive layer formed by laminating a charge generation layer and a charge transport layer on a conductive support.
When the photoreceptor is a function-separated photoreceptor, the interface between the layers has ideal conditions. For example, the interface between the charge generation layer and the charge transport layer is used for carrier injection from the charge generation layer to the charge transport layer. Designed to prevent the formation of energy level barriers. That is, it is desirable that the ionization potential of the charge transport layer is lower than that of the charge generation layer.

  The inventor of the present invention has considered that if the interface between the photosensitive member and the toner is designed as described above, the transfer process history formed on the photosensitive member can minimize the influence of the presence or absence of toner. In this way, the negative afterimage can be minimized. Based on this idea, the inventor has noticed that the quality of the negative afterimage differs depending on the combination of the photoreceptor type and the toner type. Furthermore, the inventor has found that this bias is suppressed by making the difference between the ionization potential of the toner and the ionization potential of the photoreceptor surface 0.18 eV or less.

  Since this balance is lost when the surface of the photoconductor is altered, the ionization potential on the surface of the photoconductor is preferably high to some extent, and is preferably 5.45 eV or more and 5.53 eV or less. When the ionization potential on the surface of the photoreceptor is set to an appropriate level, chemical stability can be obtained and the degree of freedom in combining the toners is high. In addition, by properly suppressing the ionization potential, a good relationship with respect to energy matching with the base can be maintained.

  The ionization potential can be adjusted by adding an electron donating group such as an alkyl group or an alkoxy group to an organic compound, or by adding an electron donating group such as a phenyl group or an acyl group. Can do. In addition, the addition of an antioxidant that suppresses material alteration may be significant in adjusting the apparent ionization potential.

The ionization potential used in the present invention is determined based on photoelectron yield spectroscopy measurement by Hisao Ishii, Chiba University. An example of the measurement result is shown in FIG.
As a measuring device, PYS-202 commercially available from Sumitomo Heavy Industries, Ltd. was used. For the spectrum obtained by showing the n-th root (vertical axis) of the total electron yield of photoelectrons emitted by irradiating monochromatic light in the ultraviolet region as a function of incident light energy (horizontal axis), the slope on the low energy side is The ionization potential is the energy value at the intersection of the almost-appearing primary approximation line (baseline) and the primary approximation line with a large slope on the high energy side. Following Uda et al.'S research (M. Uda, Jpn. J. Appl. Phys. 24 (1985), 284), n is 1 or less and 1/2 for metals and 1/3 for semiconductors and organics. It is good to use. In addition, the first-order approximate straight line on the low energy side has a slight inclination depending on the type of the photoreceptor surface. Any surface of the photoreceptor having an inclination of zero or less has good suppression of negative afterimages and is advantageous in the present invention.
This inclination reflects the fluctuation of the ionization potential and is considered to represent the property of charge trapping on the surface of the photoreceptor that affects the formation of a negative afterimage.

  In order to suppress the negative afterimage, it is better to reduce the space charge remaining in the photosensitive layer. Not only the surface of the photoreceptor but also the property that space charges are stocked at each layer and the interface between the layers may cause unintended modulation of the photoreceptor surface potential. At this time, negative afterimages may or may not appear even if the conditions are adjusted, and the phenomenon may be complicated and uncontrollable. When the photosensitive layer of the photoreceptor is composed of a plurality of layers of two or more layers, it is advantageous that the energy level of each layer has a small energy barrier relationship in order to stably exhibit the above-described effects. As this specific relationship, when the difference in ionization potential between the layers is set to 0.30 eV or less, it is possible to suppress an unstable behavior in which a negative afterimage appears or does not appear.

The method for producing a toner for developing an electrostatic latent image used in the image forming apparatus of the present invention is particularly limited as long as the difference between the ionization potential on the surface of the photoreceptor and the ionization potential of the toner is 0.18 eV or less. It is not something.
The toner used in the image forming apparatus of the present invention has a configuration described below. However, the following description is a representative example of the embodiment of the present invention, and can be modified as appropriate.

<Configuration of toner>
As the toner used in the present invention, either a pulverized toner or a polymerized toner can be used as long as the ionization potential between the photoreceptor surface and the toner surface satisfies the predetermined condition described above. Among these, the following polymerized toner is preferably used for high-quality image formation.
The polymerized toner is manufactured by a toner manufacturing method including a toner material dissolution or dispersion preparation step, an emulsification or dispersion step, and an organic solvent removal step, and the crystalline polyester resin is unevenly distributed on the toner surface.
The crystalline polyester resin is preferably unevenly distributed within 1 μm from the toner surface.
As described above, the crystalline polyester resin having a fixing assisting function and a function of rapidly melting is unevenly distributed on the toner surface, so that it rapidly diffuses on the toner surface during heating. Further, by uniformly distributing the crystalline polyester resin particles with a small particle diameter on the toner surface, a toner having excellent durability can be obtained without being peeled off compared to a case where the particles are adhered to the toner surface in a lump. .

First, after dyeing in the state of the toner, by preparing a section, the dyeing material soaks from the toner surface, and the state of the coating composed of resin fine particles existing on the surface portion of the toner particle to be photographed is clearer Obtained as the contrast difference. For example, when the coating composed of resin fine particles and the organic component inside the coating are different, the coating portion can be distinguished from the resin inside the toner.
Next, the crystalline polyester resin is obtained as a clear contrast by dyeing after sectioning. The crystalline polyester resin is dyed weaker than the organic component constituting the inside of the toner. This is presumably because the infiltration of the dye material into the crystalline polyester resin is weaker than the organic component inside the toner due to a difference in density.
In this way, the amount of ruthenium atoms varies depending on the intensity of the staining, so the portion that is strongly stained has many of these atoms, the electron beam does not pass through, and it becomes black on the observed image and is weakly stained. The portion where the electron beam is easily transmitted is white on the observation image.

  The ratio of the crystalline polyester resin existing within 1 μm from the surface of the toner can be calculated by designating the area of the crystalline polyester resin portion in the image of the toner cross section and obtaining it by image processing. That is, the ratio of the crystalline polyester resin existing within 1 μm from the surface of the toner is calculated by the ratio of the area of the crystalline polyester resin existing within 1 μm from the surface to the total area of the detected crystalline polyester resin. Can do.

<Crystalline polyester resin>
Examples of the crystalline polyester resin include saturated aliphatic diol compounds having 2 to 12 carbon atoms as alcohol components, particularly 1,4-butanediol, 1,6-hexanediol, 1,8-8 octanediol, and 1,10-decane. A diol, 1,12-dodecanediol or a derivative thereof, and a dicarboxylic acid having 2 to 12 carbon atoms having a double bond (C = C bond) as an acidic component, or a saturated dicarboxylic acid having 2 to 12 carbon atoms, particularly Synthesis using fumaric acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,10-decanedioic acid, 1,12-dodecanedioic acid or their derivatives A crystalline polyester resin is suitable. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1 from the viewpoint of further reducing the difference between the endothermic peak temperature and the endothermic shoulder temperature. , 12-dodecanediol and at least one alcohol component selected from fumaric acid, 1,4-butanedioic acid, 1,6-hexanedioic acid, 1,8-octanedioic acid, 1,10-decanedioic acid Particularly preferred are those synthesized from an acid and at least one dicarboxylic acid component selected from 1,12-dodecanedioic acid.

  As a method for controlling the crystallinity and softening point of the crystalline polyester resin, a trivalent or higher polyhydric alcohol such as glycerin as an alcohol component and a trivalent or higher polyvalent such as trimellitic anhydride as an acid component can be used during polyester synthesis. Examples thereof include a method of designing and using a non-linear polyester resin that has been subjected to condensation polymerization by adding a polyvalent carboxylic acid.

The molecular structure of the crystalline polyester resin can be confirmed by X-ray diffraction, GC / MS, LC / MS, IR measurement, etc. in addition to NMR measurement by solution or solid. As a simple example, an infrared absorption spectrum having absorption at 965 ± 10 cm ⁻¹ or 990 ± 10 cm ⁻¹ based on δCH (out-of-plane variable angular vibration) of an olefin can be given as an example.

  As for the molecular weight of the crystalline polyester resin, o-dichlorobenzene is soluble from the viewpoint that the molecular weight distribution is sharp and the low molecular weight is excellent in low temperature fixability, and that the heat resistant storage stability is deteriorated when there are many components having low molecular weight. In the molecular weight distribution by GPC of the minute, the peak position of the molecular weight distribution diagram in which the horizontal axis is log (M) and the vertical axis is expressed by mass% is in the range of 3.5 to 4.0, and the half width of the peak is 1. 5 or less, the weight average molecular weight (Mw) is preferably 3,000 to 30,000, the number average molecular weight (Mn) is 1,000 to 10,000, and the Mw / Mn is preferably 1 to 10, and the weight average More preferably, the molecular weight (Mw) is 5,000 to 15,000, the number average molecular weight (Mn) is 2,000 to 10,000, and Mw / Mn is 1 to 5.

The acid value of the crystalline polyester resin is preferably 5 mgKOH / g or more and preferably 10 mgKOH / g or more in order to achieve the desired low-temperature fixability from the viewpoint of the affinity between paper and resin. It is more preferable. On the other hand, in order to improve hot offset property, it is preferable that an acid value is 45 mgKOH / g or less.
The hydroxyl value of the crystalline polyester resin is preferably 50 mgKOH / g or less, more preferably 5 to 50 mgKOH / g, in order to achieve a predetermined low-temperature fixability and to achieve good charging characteristics. preferable.

The crystalline polyester resin is used as an organic solvent dispersion containing 5 to 25 parts by mass of the crystalline polyester resin in 100 parts by mass of the crystalline polyester resin dispersion, and an average particle diameter (dispersion diameter) of 10 to 500 nm is used. ).
If the dispersion diameter of the crystalline polyester resin is less than 10 nm, the crystalline polyester resin aggregates inside the toner particle main body, and there is a possibility that a sufficient charge imparting effect cannot be obtained. On the other hand, if the dispersion diameter of the crystalline polyester resin exceeds 500 nm, the surface property of the toner deteriorates, the carrier is contaminated and sufficient chargeability cannot be maintained over a long period of time, and environmental stability is further improved. May interfere.

  The organic solvent dispersion of the crystalline polyester resin preferably contains 5 parts by mass of the crystalline polyester resin and 5 to 25 parts by mass of the binder resin in 100 parts by mass of the dispersion. More preferably, 5 parts by mass and 15 parts by mass of the binder resin are included. If the binder resin is less than 5 parts by mass, the dispersed diameter of the crystalline polyester resin may not be reduced. If the binder resin exceeds 25 parts by mass, aggregation occurs when added to the solution or dispersion of the toner material. May occur, and the low-temperature fixing effect may not be sufficiently obtained.

  The crystalline polyester dispersion referred to in the present invention is preferably finely dispersed in the same solvent as the organic solvent used for toner production, and is used for toner production while being dispersed in the organic solvent. Thus, when the toner composition is emulsified in an aqueous medium, the crystalline polyester can exist while being finely dispersed in the toner oil droplets, and can move to the oil-water interface in the droplets. The effect of can be demonstrated. In the present invention, the crystalline polyester resin dissolves in an organic solvent when heated, and recrystallizes and precipitates when cooled. This precipitate is often larger than the required particle size, and is preferably dispersed and pulverized in a liquid. The property that requires this precipitation and dispersion step is important for arranging on the toner surface in the form of needle crystals and ensuring low-temperature fixability, durability, and cleaning properties.

  The content of the crystalline polyester resin is preferably 1 part by mass to 30 parts by mass with respect to 100 parts by mass of the toner. When the content is less than 1 part by mass, a sufficient low-temperature fixing effect may not be obtained. When the content exceeds 30 parts by mass, the amount of crystalline polyester resin present on the toner surface is too large, so that the photoconductor. In addition, the image quality may be deteriorated due to contamination of other members, the fluidity of the developer may be lowered, and the image density may be lowered. Further, the surface property of the toner is deteriorated, the carrier is contaminated and sufficient chargeability cannot be maintained for a long time, and further, environmental stability may be hindered.

The solution or dispersion of the toner material contains a cationic compound, and the aqueous medium contains anionic resin fine particles having an average particle size of 5 μm to 50 μm and an anionic surfactant. Is preferable in that the particle size distribution becomes sharper without becoming too small.
The cationic compound is presumed to have a function of preventing the stabilization of oil droplets of ultrafine particles and automatically adjusting the size of the oil droplets appropriately. Further, when the cationic compound is increased, the amount of the resin fine particles adsorbed on the toner is increased, the oil droplets are protected, and coalescence hardly occurs.

Here, the case where an aqueous medium containing anionic resin fine particles having an average particle diameter of 5 nm to 50 nm and an anionic surfactant is used will be described in detail.
In the obtained toner, resin fine particles are attached to the toner surface having a toner material mainly including a colorant and a binder resin as a core. The average particle diameter of the toner is adjusted by emulsification or dispersion conditions such as stirring of the aqueous medium in the emulsification step.

  The anionic resin fine particles adhere to the toner surface, and are fused and fused to form a relatively hard surface. Accordingly, it is preferable that a crystalline polyester resin is simultaneously present in the layer of the anionic resin fine particles on the toner surface in order to exhibit a further excellent effect of durability. Further, since the resin fine particles have an anionic property, they have an effect of adsorbing to the droplets containing the toner material and suppressing coalescence of the droplets, and are important for controlling the particle size distribution of the toner. Furthermore, negative chargeability of the toner can be given. In order to exert these effects, the anionic resin fine particles preferably have an average particle size of 5 nm to 50 nm.

-Resin fine particles-
The resin in the resin fine particles is not particularly limited as long as it can form an aqueous dispersion in an aqueous medium, and can be appropriately selected from known resins according to the purpose. The resin for the resin fine particles may be a thermoplastic resin or a thermosetting resin. For example, vinyl resin, polyurethane resin, epoxy resin, polyester resin, polyamide resin, polyimide resin, silicon resin, phenol resin, melamine Resins, urea resins, aniline resins, ionomer resins, polycarbonate resins, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, at least one selected from a vinyl resin, a polyurethane resin, an epoxy resin, and a polyester resin is particularly preferable in that an aqueous dispersion of fine spherical resin fine particles can be easily obtained.
The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer. For example, styrene- (meth) acrylate resin, styrene-butadiene copolymer, (meth) acrylic acid-acrylate polymer, styrene -An acrylonitrile copolymer, a styrene-maleic anhydride copolymer, a styrene- (meth) acrylic acid copolymer, etc. are mentioned.

The resin fine particles are preferably anionic. This is because they are not aggregated when used together with the anionic surfactant shown above. The resin fine particles can also be produced by using an anionic activator by a production method described later or by introducing an anionic group such as a carboxylic acid group or a sulfonic acid group into the resin.
The particle diameter of the resin fine particles is preferably 5 nm to 50 nm as the average particle diameter of primary particles from the viewpoint of controlling the particle diameter and particle diameter distribution of the emulsified particles, and more preferably 10 nm to 25 nm.
The average particle diameter of the primary particles of the resin fine particles can be measured by, for example, SEM, TEM, light scattering method or the like. Preferably, the measurement may be performed by diluting to an appropriate concentration so as to fall within the measurement range by LA-920 manufactured by Horiba Seisakusho using the laser scattering measurement method. The particle diameter is determined as a volume average diameter.

The resin fine particles are not particularly limited, and can be obtained by polymerization according to a known method appropriately selected according to the purpose, but is preferably obtained as an aqueous dispersion of resin fine particles. As a method for preparing an aqueous dispersion of resin fine particles, for example, the following method is preferably exemplified.
(1) In the case of a vinyl resin, an aqueous dispersion of resin fine particles directly by a polymerization reaction selected from a suspension polymerization method, an emulsion polymerization method, a seed polymerization method and a dispersion polymerization method using a vinyl monomer as a starting material (2) In the case of polyaddition or condensation type resins such as polyester resins, polyurethane resins, and epoxy resins, a precursor (monomer, oligomer, etc.) or a solvent solution thereof in an aqueous medium in the presence of an appropriate dispersant. (3) In the case of polyaddition or condensation resin such as polyester resin, polyurethane resin, epoxy resin, etc. , After dissolving an appropriate emulsifier in a precursor (monomer, oligomer, etc.) or a solvent solution thereof (preferably in a liquid form, which may be liquefied by heating) Method of phase inversion emulsification by adding water (4) Mechanical rotation of a resin prepared in advance by a polymerization reaction (any polymerization reaction mode such as addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) A method of dispersing resin particles in water in the presence of a suitable dispersing agent after obtaining resin fine particles by pulverization using a fine pulverizer such as a formula or jet type, and then classifying (5) polymerization reaction (addition polymerization) After obtaining resin fine particles by spraying a resin solution prepared by dissolving a resin prepared by ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc. in a solvent in a mist form (6) A method of dispersing the resin fine particles in water in the presence of a suitable dispersant (6) A polymerization reaction (addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.) Resin) prepared by The resin fine particles are precipitated by adding a poor solvent to the resin solution dissolved in the agent or by cooling the resin solution previously heated and dissolved in the solvent, and then removing the solvent to obtain resin fine particles. (7) prepared in advance by a polymerization reaction (any polymerization reaction mode such as addition polymerization, ring-opening polymerization, polyaddition, addition condensation, condensation polymerization, etc.). A method in which a resin solution in which a resin is dissolved in a solvent is dispersed in an aqueous medium in the presence of an appropriate dispersant, and then the solvent is removed by heating or decompression, etc. (8) Polymerization reaction (addition polymerization, ring-opening polymerization, A suitable emulsifier is dissolved in a resin solution prepared by dissolving a resin prepared by a polyaddition, addition condensation, condensation polymerization, etc.) in a solvent, and then water is added for phase inversion emulsification. Method.

-Anionic surfactant-
Examples of the anionic surfactant include alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, and the like, and anionic surfactants having a fluoroalkyl group are preferable. Examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms or a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 3- [ω-fluoroalkyl (having 6 to 6 carbon atoms). 11) Sodium oxy] -1-alkyl (C3-4) sulfonate, sodium 3- [ω-fluoroalkanoyl (C6-8) -N-ethylamino] -1-propanesulfonate, fluoroalkyl ( Carbon number 11-20) carboxylic acid or metal salt thereof, perfluoroalkyl carboxylic acid (carbon number 7-13) or metal salt thereof, perfluoroalkyl (carbon number 4-12) sulfonic acid or metal salt thereof, perfluorooctane Sulfonic acid diethanolamide, N-propyl-N- (2-hydroxyethyl) par -Fluorooctanesulfonamide, perfluoroalkyl (carbon number 6-10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (carbon number 6-10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (carbon number 6-6) 16) Ethyl phosphate and the like.

Examples of commercially available anionic surfactants having a fluoroalkyl group include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.); Florard FC-93, FC-95, FC-98, FC-129 (manufactured by Sumitomo 3M); Unidyne DS-101, DS-102 (manufactured by Daikin Industries); Megafac F-110, F-120, F-113, F-191, F-812, F-833 (Manufactured by Dainippon Ink Co., Ltd.); Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products); Neos), etc.
Also, sodium dodecyl diphenyl ether sulfonate is preferable because it is inexpensive and easily available and there is no problem in safety.

-Cationic compound-
In the present invention, in combination with the above-mentioned resin fine particles and anionic surfactant during emulsification, the generation of a fine emulsion droplet diameter is prevented, and the crystalline polyester resin of the present invention is concentrated on the toner surface. Examples of the cationic compound include basic compounds such as amines and ammonium salts. Also preferred are diamines and triamine compounds.
The aliphatic and aromatic primary amines, secondary amines, and tertiary amines are particularly preferably primary amines and secondary amines. Butylamine, propylamine, ethylenediamine, hexamethylenediamine, isophoronediamine, aniline, o-toluidine , P-phenylenediamine, α-naphthylamine and the like. In addition, the amines exemplified in the compound containing active hydrogen capable of reacting with the reactive polyester described below can also be exemplified.

<Toner material>
The toner material includes at least an active hydrogen group-containing compound and at least the modified polyester resin that is a polymer that can react with the active hydrogen group-containing compound. It contains other components such as molds, resin fine particles, and charge control agents.

-Binder resin-
The binder resin contained in the toner material is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include polyester resins, silicone resins, styrene-acrylic resins, styrene resins, acrylic resins, epoxy resins, Examples include diene resins, phenol resins, terpene resins, coumarin resins, amideimide resins, butyral resins, urethane resins, and ethylene-vinyl acetate resins. Among these, a polyester resin having sufficient flexibility even when the molecular weight is lowered is preferable in that it can be melted sharply at the time of fixing and the surface of the image can be smoothed, and another resin is combined with the polyester resin. May be used.

The polyester resin is at least one polyol represented by the following general formula (1):
A- (OH) m ... General formula (1)
[Wherein, A represents an alkyl group having 1 to 20 carbon atoms, an alkylene group, or an aromatic group or heterocyclic aromatic group which may have a substituent. m represents an integer of 2 to 4. ]
Polyesterified with at least one polycarboxylic acid represented by the following general formula (2).
B- (COOH) n ... General formula (2)
[Wherein, B represents an alkyl group having 1 to 20 carbon atoms, an alkylene group, or an aromatic group or heterocyclic aromatic group which may have a substituent. n represents an integer of 2 to 4. ]

  The polyol represented by the general formula (1) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3 -Propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol , Polypropylene glycol, polytetramethylene glycol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, , 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, bisphenol A Bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, hydrogenated bisphenol A, hydrogenated bisphenol A ethylene oxide adduct, hydrogenated bisphenol A propylene oxide adduct, and the like.

  There is no restriction | limiting in particular as polycarboxylic acid represented by the said General formula (2), According to the objective, it can select suitably, For example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid , Isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isooctyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, n-octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, 1,2,4-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dica Boxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empor trimer Examples include acids, etc., cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, butanetetracarboxylic acid, diphenylsulfonetetracarboxylic acid, ethylene glycol bis (trimellitic acid), and the like.

-Active hydrogen group-containing compound-
In the present invention, the toner material contains an active hydrogen group-containing compound and a modified polyester resin capable of reacting with the compound, thereby increasing the mechanical strength of the resulting toner, and embedding resin fine particles and external additives. Can be suppressed. When the active hydrogen group-containing compound has a cationic polarity, the resin fine particles can be attracted electrostatically. Further, the fluidity of the toner during heat fixing can be adjusted, and the fixing temperature range can be widened. It can be said that the active hydrogen group-containing compound and the modified polyester resin capable of reacting with the compound are binder resin precursors.

  The active hydrogen group-containing compound acts as an elongation agent, a crosslinking agent, or the like when a polymer capable of reacting with the active hydrogen group-containing compound undergoes an extension reaction, a crosslinking reaction, or the like in an aqueous medium. The active hydrogen group-containing compound is not particularly limited as long as it has an active hydrogen group, and can be appropriately selected according to the purpose. For example, a polymer that can react with the active hydrogen group-containing compound contains an isocyanate group. In the case of the polyester prepolymer (A), the amines (B) are preferable because they can be increased in molecular weight by a reaction such as an elongation reaction and a crosslinking reaction with the isocyanate group-containing polyester prepolymer (A).

  The active hydrogen group is not particularly limited as long as it has an active hydrogen group, and can be appropriately selected according to the purpose. Examples thereof include a hydroxyl group (alcoholic hydroxyl group or phenolic hydroxyl group), amino group, carboxyl group, mercapto group. Groups, etc. can be used. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as amines (B), According to the objective, it can select suitably, For example, diamine (B1), trivalent or more polyamine (B2), amino alcohol (B3), amino mercaptan (B4) ), Amino acid (B5), amino acid block of B1 to B5 (B6), and the like can be used. These may be used individually by 1 type and may use 2 or more types together. Among these, diamine (B1), a mixture of diamine (B1) and a small amount of a trivalent or higher polyamine (B2) are particularly preferable.

  Examples of the diamine (B1) include aromatic diamines, alicyclic diamines, aliphatic diamines, and the like. Examples of the aromatic diamine include phenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylmethane, and the like. Examples of the alicyclic diamine include 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, diaminecyclohexane, and isophoronediamine. Examples of the aliphatic diamine include ethylene diamine, tetramethylene diamine, and hexamethylene diamine.

  Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan, aminopropyl mercaptan, and the like. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.

  Examples of the blocked B1-B5 amino group (B6) include, for example, ketimine compounds, oxazolidone compounds, and the like obtained from any of B1 to B5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) Is mentioned.

  A reaction terminator is used to stop the elongation reaction, crosslinking reaction, etc. between the active hydrogen group-containing compound and the polymer capable of reacting with the active hydrogen group-containing compound. Use of a reaction terminator is preferable in that the molecular weight and the like of the adhesive substrate can be controlled within a desired range. As the reaction terminator, monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), or those obtained by blocking them (ketimine compounds) can be used.

  As a mixing ratio of the amines (B) and the isocyanate group-containing polyester prepolymer (A), an isocyanate group [NCO] in the isocyanate group-containing prepolymer (A) and an amino group in the amines (B) [ The mixing equivalent ratio of NHx] ([NCO] / [NHx]) is preferably 1/3 to 3/1, more preferably 1/2 to 2/1, and more preferably 1 / 1.5 to Particularly preferred is 1.5 / 1. If the mixing equivalent ratio ([NCO] / [NHx]) is less than 1/3, the low-temperature fixability may be reduced. If it exceeds 3/1, the molecular weight of the urea-modified polyester resin is reduced. This is because the hot offset resistance may deteriorate.

-Polymer capable of reacting with active hydrogen group-containing compound-
The polymer capable of reacting with the active hydrogen group-containing compound (hereinafter referred to as “prepolymer”) is not particularly limited as long as it has at least a site capable of reacting with the active hydrogen group-containing compound. For example, a polyol resin, a polyacrylic resin, a polyester resin, an epoxy resin, or a derivative resin thereof can be used. These may be used individually by 1 type and may use 2 or more types together. Among these, a polyester resin is particularly preferable in terms of high fluidity and transparency during melting.

  The site capable of reacting with the active hydrogen group-containing compound in the prepolymer is not particularly limited and may be appropriately selected from known substituents. For example, an isocyanate group, an epoxy group, a carboxylic acid, an acid chloride Group, and the like. These may be contained singly or in combination of two or more. Among these, an isocyanate group is particularly preferable. Among prepolymers, it is easy to adjust the molecular weight of the polymer component, ensuring oil-free low-temperature fixing characteristics for dry toners, especially good release and fixing properties even without a release oil coating mechanism for the heating medium for fixing. In view of the capability, a urea bond-forming group-containing polyester resin (RMPE) is particularly preferable.

  As said urea bond production | generation group, an isocyanate group etc. are mentioned, for example. When the urea bond generating group in the urea bond generating group-containing polyester resin (RMPE) is the isocyanate group, the polyester resin (RMPE) is particularly preferably an isocyanate group-containing polyester prepolymer (A). The isocyanate group-containing polyester prepolymer (A) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, it is a polycondensate of a polyol (PO) and a polycarboxylic acid (PC), and Examples include those obtained by reacting an active hydrogen group-containing polyester resin with polyisocyanate (PIC). There is no restriction | limiting in particular as a polyol (PO), According to the objective, it can select suitably, For example, diol (DIO), trihydric or more polyol (TO), diol (DIO), and trihydric or more polyol ( TO) and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, diol (DIO) alone or a mixture of diol (DIO) and a small amount of a trivalent or higher polyol (TO) is preferable.

Examples of the diol (DIO) include alkylene glycols, alkylene ether glycols, alicyclic diols, alkylene oxide adducts of alicyclic diols, bisphenols, alkylene oxide adducts of bisphenols, and the like.
The alkylene glycol is preferably one having 2 to 12 carbon atoms, such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, and the like. Can be mentioned. Examples of the alkylene ether glycol include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Examples of the alicyclic diol include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A. Examples of the alkylene oxide adduct of alicyclic diol include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide to the alicyclic diol. Examples of bisphenols include bisphenol A, bisphenol F, and bisphenol S. Examples of the alkylene oxide adduct of bisphenols include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, and butylene oxide to bisphenols. Among these, alkylene glycols having 2 to 12 carbon atoms, alkylene oxide adducts of bisphenols and the like are preferable, and alkylene oxide adducts of bisphenols, alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. Mixtures are particularly preferred.

  The trivalent or higher polyol (TO) is preferably 3 to 8 or higher, for example, a trivalent or higher polyhydric aliphatic alcohol, a trivalent or higher polyphenol, a trivalent or higher polyphenol. And alkylene oxide adducts. Examples of the trivalent or higher polyhydric aliphatic alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, and the like. Examples of the trihydric or higher polyphenols include trisphenol bodies (such as Trisphenol PA manufactured by Honshu Chemical Industry Co., Ltd.), phenol novolacs, cresol novolacs, and the like. Examples of the alkylene oxide adduct of trihydric or higher polyphenols include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide to trihydric or higher polyphenols.

  The mixing mass ratio (DIO: TO) of the diol (DIO) and the trihydric or higher polyol (TO) in the mixture of the diol (DIO) and the trihydric or higher polyol (TO) is 100: 0.01 to 10 is preferable, and 100: 0.01-1 is more preferable.

  There is no restriction | limiting in particular as said polycarboxylic acid (PC), Although it can select suitably according to the objective, For example, dicarboxylic acid (DIC), trivalent or more polycarboxylic acid (TC), dicarboxylic acid (DIC) ) And a tri- or higher valent polycarboxylic acid. These may be used individually by 1 type and may use 2 or more types together. Among these, dicarboxylic acid (DIC) alone or a mixture of dicarboxylic acid (DIC) and a small amount of trivalent or higher polycarboxylic acid (TC) is preferable.

  Examples of the dicarboxylic acid (DIC) include alkylene dicarboxylic acid, alkenylene dicarboxylic acid, aromatic dicarboxylic acid, and the like. Examples of the alkylene dicarboxylic acid include succinic acid, adipic acid, and sebacic acid. Moreover, as alkenylene dicarboxylic acid, a C4-C20 thing is preferable, For example, a maleic acid, a fumaric acid, etc. are mentioned. Moreover, as aromatic dicarboxylic acid, a C8-C20 thing is preferable, for example, a phthalic acid, isophthalic acid, a terephthalic acid, naphthalene dicarboxylic acid etc. are mentioned. Among these, alkenylene dicarboxylic acid having 4 to 20 carbon atoms and aromatic dicarboxylic acid having 8 to 20 carbon atoms are preferable.

  The trivalent or higher polycarboxylic acid (TC) is preferably 3 to 8 or higher, and examples thereof include aromatic polycarboxylic acids. Moreover, as an aromatic polycarboxylic acid, a C9-C20 thing is preferable, for example, trimellitic acid, pyromellitic acid, etc. are mentioned.

  The polycarboxylic acid (PC) is selected from dicarboxylic acid (DIC), trivalent or higher polycarboxylic acid (TC), and a mixture of dicarboxylic acid (DIC) and trivalent or higher polycarboxylic acid. Any acid anhydride or lower alkyl ester may be used. Examples of the lower alkyl ester include methyl ester, ethyl ester, isopropyl ester and the like.

  As a mixing mass ratio (DIC: TC) of the dicarboxylic acid (DIC) and the trivalent or higher polycarboxylic acid (TC) in the mixture of the dicarboxylic acid (DIC) and the trivalent or higher polycarboxylic acid (TC), There is no restriction | limiting in particular, According to the objective, it can select suitably, For example, 100: 0.01-10 are preferable and 100: 0.01-1 are more preferable.

  The mixing ratio for the polycondensation reaction between the polyol (PO) and the polycarboxylic acid (PC) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, in the polyol (PO) The equivalent ratio ([OH] / [COOH]) of the hydroxyl group [OH] and the carboxyl group [COOH] in the polycarboxylic acid (PC) is preferably 2/1 to 1/1, The ratio is more preferably 1-1 / 1, and particularly preferably 1.3 / 1-1.02 / 1.

  There is no restriction | limiting in particular as content in the isocyanate group containing polyester prepolymer (A) of the said polyol (PO), Although it can select suitably according to the objective, For example, 0.5 mass%-40 mass% are Preferably, 1% by mass to 30% by mass is more preferable, and 2% by mass to 20% by mass is particularly preferable. When the content is less than 0.5% by mass, the hot offset resistance deteriorates, and it may be difficult to achieve both the heat-resistant storage stability and the low-temperature fixability of the toner, and exceeds 40% by mass. This is because the low-temperature fixability may deteriorate.

There is no restriction | limiting in particular as said polyisocyanate (PIC), According to the objective, it can select suitably, For example, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic diisocyanate, araliphatic diisocyanate, isocyanurates And those blocked with phenol derivatives, oximes, caprolactam, and the like.
Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, Examples include tetramethylhexane diisocyanate. Examples of the alicyclic polyisocyanate include isophorone diisocyanate and cyclohexylmethane diisocyanate. Examples of the aromatic diisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, diphenylene-4,4′-diisocyanate, 4,4′-diisocyanato-3,3′-dimethyldiphenyl, 3 -Methyldiphenylmethane-4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate and the like. Examples of the araliphatic diisocyanate include α, α, α ′, α′-tetramethylxylylene diisocyanate. Examples of isocyanurates include tris-isocyanatoalkyl-isocyanurate and triisocyanatocycloalkyl-isocyanurate. These may be used alone or in combination of two or more.

  The mixing ratio for reacting the polyisocyanate (PIC) with an active hydrogen group-containing polyester resin (for example, a hydroxyl group-containing polyester resin) is an isocyanate group [NCO] in the polyisocyanate (PIC) and a hydroxyl group in the hydroxyl group-containing polyester resin. The mixing equivalent ratio with [OH] ([NCO] / [OH]) is usually preferably 5/1 to 1/1, more preferably 4/1 to 1.2 / 1, Particularly preferred is 3/1 to 1.5 / 1. This is because if the isocyanate group [NCO] exceeds 5, the low-temperature fixability may deteriorate, and if it is less than 1, the offset resistance may deteriorate.

  There is no restriction | limiting in particular as content in the isocyanate group containing polyester prepolymer (A) of the said polyisocyanate (PIC), Although it can select suitably according to the objective, For example, 0.5 mass%-40 mass% Is preferable, 1 mass%-30 mass% is more preferable, and 2 mass%-20 mass% is still more preferable. When the content is less than 0.5% by mass, the hot offset resistance is deteriorated, and it may be difficult to achieve both heat-resistant storage stability and low-temperature fixability. When the content exceeds 40% by mass, This is because the low-temperature fixability deteriorates.

  As an average number of the isocyanate groups contained per molecule of the isocyanate group-containing polyester prepolymer (A), 1 or more is preferable, 1.2 to 5 is more preferable, and 1.5 to 4 is more preferable. This is because when the average number of isocyanate groups is less than 1, the molecular weight of the polyester resin (RMPE) modified with a urea bond-forming group is lowered, and the hot offset resistance is deteriorated.

  The weight average molecular weight (Mw) of the polymer capable of reacting with the active hydrogen group-containing compound is 3,000 to 40,000 in terms of molecular weight distribution by GPC (gel permeation chromatography) soluble in tetrahydrofuran (THF). Preferably, 4,000 to 30,000 is more preferable. When the weight average molecular weight (Mw) is less than 3,000, the heat resistant storage stability may be deteriorated, and when it exceeds 40,000, the low temperature fixability may be deteriorated.

The measurement of the molecular weight distribution by the gel permeation chromatography (GPC) can be performed, for example, as follows. That is, first, the column is stabilized in a 40 ° C. heat chamber, and at this temperature, tetrahydrofuran (THF) is flowed as a column solvent at a flow rate of 1 mL per minute, so that the sample concentration is 0.05 mass% to 0.6 mass%. Measurement is performed by injecting 50 to 200 μL of the tetrahydrofuran sample solution of the prepared resin. In measuring the molecular weight of the sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the calibration curve prepared by several monodisperse polystyrene standard samples and the number of counts. As a standard polystyrene sample for preparing a calibration curve, Pressure Chemical Co. Or the molecular weights made by Toyo Soda Industry Co., Ltd. are 6 × 10 ² , 2.1 × 10 ² , 4 × 10 ² , 1.75 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8. It is preferable to use 6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector can be used as the detector.

-Colorant-
The colorant is not particularly limited and may be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Lead Red, Lead Red, Cadmium Red, Cad Muum Mercury Red, Antimon Zhu, Permanent Red 4R, PA Red, Faise Red, Parachlor Ortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oh Lured, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Oxidation Chrome, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Ash Degreen Lake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Titanium Oxide, Zinc Hana, Lithbon, etc. These may be used individually by 1 type and may use 2 or more types together.

  The content of the colorant in the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1% by mass to 15% by mass, and more preferably 3% by mass to 10% by mass. When the content of the colorant is less than 1% by mass, a reduction in the coloring power of the toner is observed. When the content exceeds 15% by mass, poor dispersion of the pigment in the toner occurs, and the coloring power decreases. In some cases, the electrical characteristics of the toner may be degraded.

  The colorant may be used as a master batch combined with a resin. The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, polyester, styrene or a substituted polymer thereof, styrene copolymer, polymethyl methacrylate, polybutyl Methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic hydrocarbon resin, alicyclic Examples thereof include hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the polymer of styrene or a substituted product thereof include polyester resin, polystyrene, poly p-chlorostyrene, polyvinyl toluene, and the like. Examples of the styrene copolymer include a styrene-p-chlorostyrene copolymer, a styrene-propylene copolymer, a styrene-vinyltoluene copolymer, a styrene-vinylnaphthalene copolymer, and a styrene-methyl acrylate copolymer. Polymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene- Butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene N-acrylonitrile-indene copolymer, Styrene - maleic acid copolymer, styrene - maleic acid ester copolymer, and the like.

  The master batch can be produced by mixing or kneading a resin for a master batch and a colorant with a high shear force. At this time, it is preferable to add an organic solvent in order to enhance the interaction between the colorant and the resin. Also, the so-called flushing method is preferable in that the wet cake of the colorant can be used as it is, and there is no need to dry it. This flushing method is a method in which an aqueous paste containing water of a colorant is mixed or kneaded together with a resin and an organic solvent, and the colorant is transferred to the resin side to remove moisture and organic solvent components. For the mixing or kneading, for example, a high shear dispersion device such as a three-roll mill is preferably used. It is well known that the colorant deteriorates the charging performance of the toner when present on the toner surface. Therefore, the charging performance (environmental stability, charge retention ability, charge amount, etc.) of the toner can be improved by improving the familiarity with the resin as a master batch.

-Release agent-
There is no restriction | limiting in particular as said mold release agent, Although it can select suitably according to the objective, Melting | fusing point has a low melting point mold release agent of 50 to 120 degreeC. The low melting point release agent, when dispersed with the resin, effectively works as a release agent between the fixing roller and the toner interface, thereby preventing oilless (a release agent such as oil on the fixing roller). Even if it is not applied), the hot offset property is good.

  Suitable examples of the mold release agent include waxes and waxes. Examples of the waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax and rice wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cercin; paraffin and micro wax And natural waxes such as petroleum waxes such as crystallin and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax; synthetic waxes such as esters, ketones and ethers; Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbons; poly-n-stearyl methacrylate and poly-n-lauryl which are low molecular weight crystalline polymer resins A homopolymer or copolymer of a polyacrylate such as methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.); a crystalline polymer having a long alkyl group in the side chain, or the like may be used. These may be used alone or in combination of two or more.

There is no restriction | limiting in particular as melting | fusing point of the said mold release agent, Although it can select suitably according to the objective, 50 to 120 degreeC is preferable and 60 to 90 degreeC is more preferable. When the melting point is less than 50 ° C., the wax may adversely affect the heat resistant storage stability, and when it exceeds 120 ° C., a cold offset may easily occur during fixing at a low temperature. The melt viscosity of the release agent is preferably 5 cps to 1,000 cps, more preferably 10 cps to 100 cps, as measured at a temperature 20 ° C. higher than the melting point of the wax. If the melt viscosity is less than 5 cps, the releasability may be lowered, and if it exceeds 1,000 cps, the effect of improving hot offset resistance and low-temperature fixability may not be obtained.
There is no restriction | limiting in particular as content in the said toner of the said mold release agent, Although it can select suitably according to the objective, 40 mass% or less is preferable and 3 mass%-30 mass% are more preferable. When the content exceeds 40% by mass, the fluidity of the toner may be deteriorated.

-Charge control agent-
The charge control agent is not particularly limited and may be appropriately selected from known ones according to the purpose. Examples thereof include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, and molybdate chelate pigments. , Rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus alone or compounds thereof, tungsten alone or compounds thereof, fluorine activators, salicylic acid metal salts And metal salts of salicylic acid derivatives. These may be used individually by 1 type and may use 2 or more types together.

  As the charge control agent, a commercially available product may be used. As the commercially available product, for example, a resin or compound having an electron donating functional group, an azo dye, a metal complex of an organic acid, or the like can be used. . Specifically, Bontron 03 of nigrosine dye, Bontron P-51 of quaternary ammonium salt, Bontron S-34 of metal-containing azo dye, E-82 of oxynaphthoic acid metal complex, E of salicylic acid metal complex -84, phenolic condensate E-89 (above, manufactured by Orient Chemical Co., Ltd.), salicylic acid metal complex TN-105, quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, retention Tsuchiya Chemical Industry Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038, triphenylmethane derivative copy blue PR, quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst) , LRA-901, LR-147 which is a boron complex (Nippon Curry , Copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

  The charge control agent can be arbitrarily contained in the resin phase in the toner by utilizing the difference in affinity for the resin in the toner. By selectively containing the charge control agent in the resin phase in the toner existing in the inner layer, it is possible to suppress the spent of the charge control agent to other members such as a photoreceptor and a carrier. In the toner of the present invention, the arrangement of the charge control agent may be designed relatively freely, and any arrangement may be taken according to each image forming process.

-Inorganic fine particles-
The inorganic fine particles are used as an external additive for imparting fluidity, developability, chargeability and the like to the toner. The inorganic fine particles are not particularly limited and may be appropriately selected from known ones according to the purpose. For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, titanate Strontium, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, carbonized Examples thereof include silicon and silicon nitride. These may be used individually by 1 type and may use 2 or more types together.

As the inorganic fine particles for assisting the fluidity, developability and chargeability of the toner, in addition to the large inorganic particles having a primary average particle size of 80 nm to 500 nm, small inorganic particles are preferable. Can be used. In particular, hydrophobic silica and / or hydrophobic titanium oxide are preferable. The primary average particle diameter of the inorganic fine particles is preferably 5 nm to 50 nm, and more preferably 10 nm to 30 nm. In addition, the specific surface area by BET method ^is preferably 20m ² / g~500m 2 / g. The proportion of the inorganic fine particles used is preferably 0.01% by mass to 5% by mass of the toner, and more preferably 0.01% by mass to 2.0% by mass.

  There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a fluidity improver, a cleaning property improver, a magnetic material, a metal soap, etc. are mentioned.

  The fluidity improver is an agent that performs surface treatment to increase hydrophobicity and prevents deterioration of flow characteristics and charging characteristics even under high humidity. For example, a silane coupling agent, a silylating agent, Examples thereof include a silane coupling agent having an alkyl fluoride group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, and modified silicone oil. Silica and titanium oxide are particularly preferably subjected to surface treatment with such a fluidity improver and used as hydrophobic silica and hydrophobic titanium oxide.

  The cleaning property improving agent is an agent added to the toner in order to remove the developer after transfer remaining on the photoreceptor or the primary transfer medium. For example, zinc stearate, calcium stearate, stearic acid, etc. Examples thereof include polymer fine particles produced by soap-free emulsion polymerization such as fatty acid metal salts, polymethyl methacrylate fine particles, and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and those having a volume average particle size of 0.01 μm to 1 μm are suitable.

  There is no restriction | limiting in particular as said magnetic material, According to the objective, it can select suitably from well-known things, For example, iron powder, a magnetite, a ferrite, etc. can be used. Among these, white is preferable in terms of color tone.

(Toner production method)
The method for producing a polymerized toner in the present invention includes a toner material dissolution or dispersion preparation step, an emulsification or dispersion step, and an organic solvent removal step, and further includes other steps as necessary.

In the present invention, the difference (Dw2−Dw1) between the weight average particle diameter Dw1 of the toner immediately before completion of the emulsification or dispersion process and the weight average particle diameter Dw2 of the toner obtained by the organic solvent removal process is 1 μm. And preferably within 0.5 μm.
The particle size immediately before the end of emulsification of the toner and the weight average particle size Dw2 after removal of the organic solvent (after Dw toner conversion) should be sampled in a small amount after the removal step of the organic solvent and diluted with a large excess of ion-exchanged water. Can be measured.
The weight average particle diameter Dw2 of the toner immediately before the end of emulsification (immediately before the end of emulsification) is affected by the subsequent coalescence by sampling a small amount in a shearing state and immediately diluting with a large excess of ion-exchanged water. It is possible to measure the weight average particle size in an emulsified state.
The difference (Dw2-Dw1) represents the degree of increase in the weight average particle diameter. When the difference (Dw2-Dw1) exceeds 1 μm, the crystalline polyester fine particles may not be disposed on the toner surface.

<Toner material dissolution or dispersion preparation process>
The toner material dissolution or dispersion preparation step is a step of preparing a toner material dissolution or dispersion by dissolving or dispersing a toner material containing at least a binder resin and a crystalline polyester resin dispersion in an organic solvent. is there.

  The toner material is not particularly limited as long as the toner can be formed, and can be appropriately selected according to the purpose. For example, it can react with a binder resin, an active hydrogen group-containing compound, or the active hydrogen group-containing compound. A polymer (prepolymer) and a colorant, and may further contain other components such as a mold release agent and a charge control agent, if necessary. The solution or dispersion of the toner material is preferably prepared by dissolving or dispersing the toner material and the crystalline polyester resin dispersion in an organic solvent. The organic solvent is preferably removed during or after the toner granulation.

-Organic solvent-
The organic solvent that dissolves or disperses the toner material is not particularly limited as long as it is a solvent that can dissolve or disperse the toner material, and can be appropriately selected according to the purpose. Those having a boiling point of less than 150 ° C. are preferable in terms of ease of subsequent removal. For example, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, Examples include chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. Further, ester solvents are preferable, and ethyl acetate is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.

  There is no restriction | limiting in particular as the usage-amount of the said organic solvent, Although it can select suitably according to the objective, 40 mass parts-300 mass parts are preferable with respect to 100 mass parts of toner materials, 60 mass parts-140 mass parts. Is more preferable, and 80 to 120 parts by mass is still more preferable. It should be noted that the toner material is dissolved or dispersed in an organic solvent in a crystalline polyester resin dispersion, an active hydrogen group-containing compound, a polymer capable of reacting with an active hydrogen group-containing compound, an unmodified polyester resin, a release agent. It can be carried out by dissolving or dispersing toner materials such as a colorant, a colorant and a charge control agent. In the toner material, components other than the polymer (prepolymer) capable of reacting with the active hydrogen group-containing compound may be added and mixed in the aqueous medium in the preparation of the aqueous medium described later. When the dissolved or dispersed liquid of the toner material is added to the aqueous medium, it may be added to the aqueous medium together with the dissolved or dispersed liquid.

<Emulsification or dispersion process>
The emulsification and dispersion step is a step of preparing an emulsification or dispersion by adding a solution or dispersion of the toner material to an aqueous medium and emulsifying or dispersing the toner material.

-Aqueous medium-
The aqueous medium is not particularly limited and can be appropriately selected from known ones. For example, water, a water-miscible solvent, a mixture thereof, and the like can be used. Among these, Water is particularly preferred. The solvent miscible with water is not particularly limited as long as it is miscible with water. For example, alcohol, dimethylformamide, tetrahydrofuran, cellosolves, lower ketones, and the like can be used. Examples of the alcohol include methanol, isopropanol, and ethylene glycol. Examples of lower ketones include acetone and methyl ethyl ketone. These may be used individually by 1 type and may use 2 or more types together.

  The aqueous medium is prepared, for example, by dispersing resin fine particles in an aqueous medium in the presence of an anionic surfactant. There is no restriction | limiting in particular as the addition amount to the aqueous medium of anionic surfactant and resin fine particle, According to the objective, it can select suitably, For example, 0.5 mass%-10 mass% are respectively preferable.

-Emulsification or dispersion-
To dissolve or disperse the toner material in the aqueous medium, it is preferable to disperse the toner material dissolved or dispersed in the aqueous medium while stirring. There is no restriction | limiting in particular as a dispersion method, According to the objective, it can select suitably, For example, it can carry out using a well-known disperser etc. Examples of the disperser include a low speed shear disperser and a high speed shear disperser. In this toner production method, an adhesive base material is formed when an active hydrogen group-containing compound and a polymer capable of reacting with the active hydrogen group-containing compound are subjected to an extension reaction or a crosslinking reaction during emulsification or dispersion. .
The particle diameter during emulsification is appropriately monitored, and the shearing conditions, the anionic surfactant, the amount of resin fine particles, and the addition amount of the cation component are adjusted to match the desired emulsified particle diameter. Thereafter, the difference from the toner particle diameter from which the solvent has been removed is observed, and the shearing condition, the amount of the anionic surfactant, the amount of resin fine particles, and the amount of addition of the cation component are adjusted again so as to reduce the value.
As a result, the crystalline polyester resin can be uniformly disposed on the toner surface.

  The urea-modified polyester resin may be prepared by, for example, dissolving or dispersing a toner material containing a polymer (for example, an isocyanate group-containing polyester prepolymer (A)) capable of reacting with an active hydrogen group-containing compound into an active hydrogen group. It may be produced by emulsifying or dispersing in an aqueous medium together with the containing compound (for example, amines (B)), forming oil droplets, and subjecting both to an extension reaction or a crosslinking reaction in the aqueous medium. 2) The toner material dissolved or dispersed is emulsified or dispersed in an aqueous medium to which an active hydrogen group-containing compound has been added in advance to form oil droplets, and both are subjected to an extension reaction or a crosslinking reaction in the aqueous medium. It may be generated. Alternatively, (3) after dissolving and dispersing the toner material in an aqueous medium, the active hydrogen group-containing compound is added to form oil droplets, and both extend from the particle interface in the aqueous medium. It may be generated by a reaction or a crosslinking reaction. In the case of (3), the modified polyester resin is preferentially produced on the surface of the toner to be produced, and it becomes possible to provide a concentration gradient on the toner particles.

  The reaction conditions for producing the binder resin by emulsification or dispersion are not particularly limited and may be appropriately selected according to the combination of the polymer capable of reacting with the active hydrogen group-containing compound and the active hydrogen group-containing compound. Can do. In addition, as reaction time, 10 minutes-40 hours are preferable, and 2 hours-24 hours are more preferable.

  Examples of a method for stably forming a dispersion containing a polymer capable of reacting with an active hydrogen group-containing compound (for example, an isocyanate group-containing polyester prepolymer (A)) in an aqueous medium include, for example, an activity in an aqueous medium. Dissolve or disperse a toner material such as a polymer capable of reacting with a hydrogen group-containing compound (for example, an isocyanate group-containing polyester prepolymer (A)), a colorant, a release agent, a charge control agent, and an unmodified polyester resin in an organic solvent. For example, a method of adding a solution or dispersion of a toner material prepared in such a manner and dispersing the toner material by shearing force may be used.

In emulsification or dispersion, the amount of the aqueous medium used is preferably 50 parts by mass to 2,000 parts by mass, and more preferably 100 parts by mass to 1,000 parts by mass with respect to 100 parts by mass of the toner material. If the amount used is less than 50 parts by mass, the toner material may be poorly dispersed, and toner particles having a predetermined particle size may not be obtained. If the amount exceeds 2,000 parts by mass, the production cost increases. Because.
In addition to the anionic surfactant and resin fine particles described above, the following inorganic compound dispersant and polymer protective colloid can be used in combination with the aqueous medium. Examples of the hardly water-soluble inorganic compound dispersant include tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite.

  Examples of the polymer protective colloid include acids, (meth) acrylic monomers containing hydroxyl groups, ethers such as vinyl alcohol or vinyl alcohol, esters of vinyl alcohol and a compound containing a carboxyl group, amides Examples include compounds or homopolymers or copolymers of these methylol compounds, chlorides, those having a nitrogen atom or a heterocyclic ring thereof, polyoxyethylene compounds, and celluloses.

Examples of the acids include acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and the like.
Examples of the (meth) acrylic monomer containing a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, and γ-acrylate. -Hydroxypropyl, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, Examples include glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide and the like.

  Examples of the vinyl alcohol or ethers with vinyl alcohol include vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, and the like. Examples of esters of a compound containing vinyl alcohol and a carboxyl group include vinyl acetate, vinyl propionate, and vinyl butyrate. Moreover, as an amide compound or these methylol compounds, acrylamide, methacrylamide, diacetone acrylamide acid, or these methylol compounds etc. are mentioned, for example.

  Examples of the chlorides include acrylic acid chloride and methacrylic acid chloride. Examples of homopolymers or copolymers having a nitrogen atom or a heterocyclic ring thereof include, for example, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, and ethylene imine.

Examples of the polyoxyethylene compound include polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, Examples include polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, and polyoxyethylene nonyl phenyl ester.
Examples of the celluloses include methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose.

  In addition, when using a dispersion stabilizer that can be dissolved in an acid or alkali such as calcium phosphate, the calcium phosphate is dissolved from the fine particles by dissolving the calcium phosphate with an acid such as hydrochloric acid and then washing with water or decomposing with an enzyme. Can be removed.

<Organic solvent removal step>
The organic solvent removing step is a step of removing the organic solvent from the emulsion or dispersion.

-Removal of organic solvent-
The organic solvent is removed from the emulsified slurry obtained by emulsification or dispersion. The organic solvent is removed by (1) a method of gradually raising the temperature of the entire reaction system to completely evaporate and remove the organic solvent in the oil droplets, and (2) spraying the emulsified dispersion in a dry atmosphere, Examples thereof include a method in which the water-insoluble organic solvent in the droplets is completely removed to form toner fine particles, and the aqueous dispersant is removed by evaporation. When the organic solvent is removed, toner particles are formed. The formed toner particles are washed, dried, etc., and then classified as desired. The classification is performed, for example, by removing fine particle portions in a liquid by a cyclone, a decanter, centrifugation, or the like. The classification operation may be performed after obtaining the powder after drying.

  The obtained toner particles are mixed with particles such as a colorant, a release agent, and a charge control agent, and further, a mechanical impact force is applied, so that particles such as a release agent are removed from the surface of the toner particles. Desorption can be prevented. As a method of applying a mechanical impact force, for example, a method of applying an impact force to a mixture with a blade rotating at high speed, a mixture of particles in a high-speed air stream and acceleration to mix particles or a composite particle is a suitable collision plate. And the like. As an apparatus used in this method, for example, an ong mill (manufactured by Hosokawa Micron Co., Ltd.), an I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) and a pulverization air pressure is lowered, a hybridization system (Co., Ltd.) Nara Machinery Co., Ltd.), Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar, and the like.

  The toner has the following weight average particle diameter (Dw), weight average particle diameter (Dw) / number average particle diameter (Dn), average circularity, volume resistivity, BET specific surface area, and the like. It is preferable.

  The toner has a weight average particle diameter of preferably 1 μm to 6 μm, and more preferably 2 μm to 5 μm. When the weight average particle size of the toner is less than 1 μm, toner dust may easily occur in the primary transfer and the secondary transfer, and when it exceeds 6 μm, the dot reproducibility becomes insufficient, and the halftone portion In some cases, the graininess is also deteriorated and a high-definition image cannot be obtained.

The ratio (Dw / Dn) of the weight average particle diameter (Dw) to the number average particle diameter (Dn) in the toner is preferably 1.25 or less, more preferably 1.05 to 1.25.
When the ratio of the weight average particle diameter to the number average particle diameter (Dw / Dn) is less than 1.05, in the two-component developer, the toner is fused to the surface of the carrier during long-term stirring in the developing device, It tends to lead to a decrease in chargeability of the carrier and a deterioration in cleaning properties. In the case of a one-component developer, toner filming on the developing roller and toner fusion to a member such as a blade may easily occur because the toner is thinned. When Dw / Dn exceeds 1.25, it becomes difficult to obtain a high-resolution and high-quality image, and the toner particle diameter varies greatly when the balance of the toner in the developer is performed. May be. On the other hand, by reducing the ratio of the weight average particle diameter to the number average particle diameter (Dw / Dn), the charge amount distribution becomes uniform and the background fog can be reduced. If the ratio of the weight average particle diameter to the number average particle diameter (Dw / Dn) exceeds 1.25, it becomes difficult to obtain a high-quality image because the toner charge amount distribution becomes wide.

  Further, when the ratio of the weight average particle diameter to the number average particle diameter (Dw / Dn) of the toner is 1.05 to 1.25, any of storage stability, low-temperature fixability, and hot offset resistance can be obtained. Also tends to be an excellent toner. In particular, when used in a full-color copying machine, the glossiness of the image is excellent. Even if the toner balance over a long period of time is achieved with a two-component developer, the toner particle diameter in the developer is less likely to fluctuate, and good and stable developability can be obtained even with long-term agitation in the developing device. With toner balance, the fluctuation of the toner particle size is reduced, and there is no toner filming on the developing roller and no toner fusion to a member such as a blade for thinning the toner. Good and stable developability can be obtained even during long-term use (stirring) of the apparatus, and high-quality images can be obtained.

  The weight average particle diameter (Dw) and number average particle diameter (Dn) of the toner were measured with a particle size measuring device (“Multisizer III”, manufactured by Beckman Coulter, Inc.) at an aperture diameter of 100 μm, and analyzed software (Beckman Coulter). Analysis was performed using Multisizer 3 Version 3.51). Specifically, 0.5 ml of 10% by weight surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 ml beaker made of glass, and 0.5 g of each toner is added. The mixture was stirred with a micropartel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter, Inc.) as the measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the apparatus was 8 ± 2%. In this measurement method, it is important that the concentration is 8 ± 2% from the viewpoint of the reproducibility of the particle size. Within this concentration range, no error occurs in the particle size.

-Average circularity-
The average circularity of the toner is preferably 0.950 to 0.990. If the average circularity is less than 0.950, the image uniformity during development deteriorates, and the toner transfer efficiency from the photosensitive member to the intermediate transfer member or from the intermediate transfer member to the recording medium decreases, resulting in uniform transfer. It becomes impossible. The toner of the present invention is produced by emulsification in an aqueous medium, and is particularly effective for reducing the particle size of color toners and obtaining a shape with an average circularity in the above range. is there.
The average circularity of the toner is defined by the average circularity SR = (peripheral length of a circle having the same area as the particle projection area / perimeter length of the particle projection image) × 100%. Measurement was performed using a flow particle image analyzer (“FPIA-2100”, manufactured by Sysmex Corporation), and analysis was performed using analysis software (FPIA-2100 Data Processing Program For FPIA Version 00-10). Specifically, 10% by weight surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a glass 100 ml beaker, and each toner 0 0.1 g to 0.5 g was added, and the mixture was stirred with a micropartel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). Using the FPIA-2100, the dispersion was measured for toner shape and distribution until a concentration of 5,000 to 15,000 / μl was obtained. In this measurement method, it is important that the concentration of the dispersion is 5,000 to 15,000 / μL from the viewpoint of measurement reproducibility of average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. Further, the toner addition amount differs from the particle size, and it is necessary to decrease the small particle size and increase the large particle size. When the toner particle size is 3 μm to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5,000 to 15,000 / μl.

-Volume resistivity of toner-
The common logarithmic value Log ρ of the volume specific resistance ρ (Ωcm) of the toner is preferably 10.9 LogΩcm to 11.4 LogΩcm. Thereby, the dispersion state of the colorant and the like in the toner is good, good charge stability of the toner is obtained, and toner scattering and fogging are good. When the Log ρ of the toner is smaller than 10.9 Log Ωcm, the conductivity becomes high, which causes a charging failure and tends to increase background contamination, toner scattering, and the like. In addition, an abnormal image is generated due to an electrostatic offset or the like, and a high-quality image cannot be stably obtained. Further, when the Log ρ of the toner is larger than 11.4 Log Ωcm, the resistance becomes high, so that the charge amount increases and the image density may decrease.

-BET specific surface area of toner-
BET specific surface area of the toner ^is preferably 0.5m ² /g~4.0m 2 / ^g, more preferably 0.5m ² /g~2.0m 2 / g. When the BET specific surface area is less than 0.5 m ² / g, the entire surface of the toner is covered tightly, and the resin fine particles inhibit the adhesiveness between the binder resin component inside the toner and the fixing paper, thereby fixing the toner. An increase in the minimum temperature is observed. Further, the resin fine particles impede the exudation of the wax, and the effect of releasing the wax cannot be obtained, and the occurrence of offset is observed. On the other hand, when the BET specific surface area exceeds 4.0 m ² / g, the organic fine particles remaining on the toner surface largely protrude as convex portions, or the resin fine particles remain as a coarse multiple layer. Adhesion between the binder resin component inside the toner and the fixing paper is hindered, and an increase in the minimum fixing temperature is observed. Further, the resin fine particles impede the exudation of the wax, and the effect of releasing the wax cannot be obtained, and the occurrence of offset is observed. Further, the additive is raised, and the image quality is likely to be affected by the unevenness of the surface.

  The coloration of the toner is not particularly limited and may be appropriately selected according to the purpose, and may be at least one selected from black toner, cyan toner, magenta toner, and yellow toner. Can be obtained by appropriately selecting the type of the colorant, and is preferably a color toner.

(Developer)
The developer of the present invention contains at least the toner of the present invention, and other components such as a carrier selected appropriately. The developer may be a one-component developer or a two-component developer. However, when it is used for a high-speed printer or the like corresponding to the recent improvement in information processing speed, the life is improved. In view of the above, the two-component developer is preferable.
In the case of the one-component developer using the toner, even if the balance of the toner is performed, there is little fluctuation in the particle diameter of the toner, and the filming of the toner on the developing roller as the developer carrier or the toner is thinned. There is no fusion of toner to a layer thickness regulating member such as a blade for layering, and good and stable developability and images can be obtained even when the developing means is used for a long time (stirring). Further, in the case of the two-component developer using the toner, even if the toner balance is maintained over a long period of time, the toner particle diameter in the developer is small, and even if it is stirred for a long time in the developing means, it is good and stable. Developability is obtained.

-Career-
There is no restriction | limiting in particular as said carrier, Although it can select suitably according to the objective, What has a core material and the resin layer which coat | covers this core material is preferable.

  There is no restriction | limiting in particular as a material of the said core material, It can select suitably from well-known things, For example, a manganese-strontium (Mn-Sr) type material of 50 emu / g-90 emu / g, manganese-magnesium ( Mn—Mg) -based materials are preferable, and in terms of securing image density, highly magnetized materials such as iron powder (100 emu / g or more) and magnetite (75 to 120 emu / g) are preferable. In addition, a weakly magnetized material such as a copper-zinc (Cu—Zn) -based (30 to 80 emu / g) is advantageous in that it can weaken the contact with the photoconductor in which the toner is in a spiked state and is advantageous in improving the image quality. Is preferred. These may be used alone or in combination of two or more.

  The material of the resin layer is not particularly limited and may be appropriately selected from known resins according to the purpose. For example, amino resins, polyvinyl resins, polystyrene resins, halogenated olefin resins, polyesters Resin, polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexafluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride and Copolymers with vinyl fluoride, fluoroterpolymers (triple fluoride (multiple) copolymer) such as terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers, silicone resins, etc. . These may be used individually by 1 type and may use 2 or more types together. Among these, a silicone resin is particularly preferable.

The silicone resin is not particularly limited and can be appropriately selected according to the purpose from generally known silicone resins. For example, a straight silicone resin consisting only of an organosilosan bond; an alkyd resin, Examples thereof include polyester resins, epoxy resins, acrylic resins, silicone resins modified with urethane resins, and the like.
Commercially available products can be used as the silicone resin. Examples of straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical Co., Ltd .; SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicone Co., Ltd. Etc.
Commercially available products can be used as the modified silicone resin. For example, KR206 (alkyd modified), KR5208 (acryl modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical Co., Ltd .; SR2115 (epoxy-modified), SR2110 (alkyd-modified) manufactured by Dow Corning Silicone Co., Ltd., and the like.
In addition, although a silicone resin can be used alone, it is also possible to simultaneously use a component that undergoes a crosslinking reaction, a charge amount adjusting component, and the like.

  The resin layer may contain conductive powder or the like as necessary. Examples of the conductive powder include metal powder, carbon black, titanium oxide, tin oxide, and zinc oxide. The average particle diameter of these conductive powders is preferably 1 μm or less. When the average particle diameter exceeds 1 μm, it may be difficult to control electric resistance.

For example, the resin layer is prepared by dissolving the silicone resin or the like in a solvent to prepare a coating solution, and then uniformly coating the coating solution on the surface of the core material by a known coating method, drying, and baking. It can be formed by doing. Examples of the application method include an immersion method, a spray method, and a brush coating method.
There is no restriction | limiting in particular as said solvent, Although it can select suitably according to the objective, For example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cellosolve, butyl acetate, etc. are mentioned.
The baking is not particularly limited, and may be an external heating method or an internal heating method. For example, a stationary electric furnace, a fluid electric furnace, a rotary electric furnace, a burner furnace, etc. The method of using, the method of using a microwave, etc. are mentioned.

  The amount of the resin layer in the carrier is preferably 0.01% by mass to 5.0% by mass. When the amount is less than 0.01% by mass, the uniform resin layer may not be formed on the surface of the core material. When the amount exceeds 5.0% by mass, the resin layer becomes thick. In some cases, granulation of carriers occurs, and uniform carrier particles may not be obtained.

When the developer is a two-component developer, the content of the carrier in the two-component developer is not particularly limited and may be appropriately selected depending on the intended purpose. 98 mass% is preferable and 93 mass%-97 mass% are more preferable.
In general, the mixing ratio of the toner and the carrier of the two-component developer is preferably 1 part by mass to 10.0 parts by mass of the toner with respect to 100 parts by mass of the carrier.

  The carrier preferably has a weight average particle diameter Dw of 15 μm to 40 μm. When the weight average particle size is less than 15 μm, carrier adhesion that causes the carrier to be transferred together in the transfer step is likely to occur, and when it exceeds 40 μm, carrier adhesion is difficult to occur, but in order to obtain a high image density. When the toner concentration is increased, there is a possibility that background stains are likely to occur. In addition, when the dot diameter of the latent image is small, the variation in dot reproducibility increases, and the graininess of the highlight portion may be deteriorated.

The weight average particle diameter Dw of the carrier is calculated based on the particle diameter distribution (relationship between the number frequency and the particle diameter) of the particles measured on the basis of the number. The weight average particle diameter Dw in this case is represented by the following formula (1).
Dw = {1 / Σ (nD ³ )} × {Σ (nD ⁴ )} (1)
In the above formula (1), D represents the representative particle size (μm) of particles present in each channel, and n represents the total number of particles present in each channel. The channel indicates a length for equally dividing the particle size range in the particle size distribution diagram, and 2 μm is adopted in the present invention. In addition, as the representative particle size of the particles present in each channel, the lower limit value of the particle size of the particles stored in each channel was adopted.

Further, the number average particle diameter Dp of the carrier and the core material particles of the carrier is calculated based on the particle diameter distribution of the particles measured on the basis of the number. The number average particle diameter Dp in this case is represented by the formula (2).
Dp = (1 / ΣN) × (ΣnD) (2)
In the above formula (2), N represents the total number of particles measured, n represents the total number of particles present in each channel, and D represents the lower limit of the particle size of the particles stored in each channel (2 μm). Indicates.

As a particle size analyzer for measuring the particle size distribution, for example, a Microtrac particle size analyzer (model HRA9320-X100, manufactured by Honeywell) can be used. The measurement conditions are as follows.
[1] Particle size range: 8 μm to 100 μm
[2] Channel length (channel width): 2 μm
[3] Number of channels: 46
[4] Refractive index: 2.42

<Configuration of photoconductor>
The image forming apparatus of the present invention has a photosensitive member having a specific photosensitive layer on a conductive support.
Hereinafter, the photoreceptor in the present invention will be described in detail.

<Conductive support>
Examples of the conductive support include those having a volume resistivity of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, iron, tin oxide, A film or cylindrical plastic or paper coated with an oxide such as indium oxide by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, and the like, and a drawing ironing method, impact A tube that has been surface-treated by cutting, super-finishing, polishing, or the like can be used after forming a raw pipe by a method such as an ironing method, an extruded ironing method, an extracted drawing method, or a cutting method.

<Intermediate layer>
In the photoreceptor of the present invention, an intermediate layer can be provided between the conductive support and the photosensitive layer. The intermediate layer is provided for the purpose of improving adhesiveness, preventing moire, improving coatability of the upper layer, and preventing charge injection from the conductive support.

  The intermediate layer usually contains a resin as a main component. Usually, since the photosensitive layer is applied on the intermediate layer, a thermosetting resin that is hardly soluble in an organic solvent is easily used as the resin used for the intermediate layer. In particular, polyurethane, melamine resin, and alkyd-melamine resin are particularly preferable materials because many of them sufficiently satisfy the above-mentioned purpose. A paint obtained by appropriately diluting a resin with a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone can be used as a coating material. Further, fine particles such as metal or metal oxide may be added to the intermediate layer in order to adjust conductivity and prevent moire. In particular, titanium oxide or zinc oxide is preferably used.

  The fine particles can be dispersed by a ball mill, an attritor, a sand mill, or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone to obtain a coating material in which the dispersion and the resin component are mixed.

  The intermediate layer is formed by depositing the above-mentioned paint on a conductive support by a dip coating method, a spray coating method, a bead coating method or the like. If necessary, it is formed by heat curing. In many cases, the thickness of the intermediate layer is suitably about 2 μm to 20 μm. When the accumulation of the residual potential of the photoconductor becomes large, it is preferable to set it to less than 3 μm.

<Photosensitive layer>
The photosensitive layer of the photoreceptor is a laminated photosensitive layer in which a charge generation layer and a charge transport layer are sequentially laminated as a photosensitive layer.

-Charge generation layer-
The charge generation layer refers to a part of the laminated photosensitive layer and has a function of generating charges by exposure. This layer is mainly composed of a charge generating substance among the contained compounds. The charge generation layer may use a binder resin as necessary. As the charge generation material, inorganic materials and organic materials can be used.

  Examples of the inorganic material include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compound, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.

  On the other hand, as the organic material, known materials can be used, for example, metal phthalocyanines such as titanyl phthalocyanine and chlorogallium phthalocyanine, metal-free phthalocyanines, azulenium salt pigments, squaric acid methine pigments, and symmetrical carbazole skeletons. Type or asymmetric azo pigments, symmetric or asymmetric azo pigments having a triphenylamine skeleton, symmetric or asymmetric azo pigments having a fluorenone skeleton, and perylene pigments. Among these, metal phthalocyanines, symmetric or asymmetric azo pigments having a fluorenone skeleton, symmetric or asymmetric azo pigments having a triphenylamine skeleton, and perylene pigments have high quantum efficiency of charge generation. It is suitable as a material used in the invention. These charge generation materials may be used alone or as a mixture of two or more.

  Examples of the binder resin used for the charge generation layer as necessary include, for example, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly -N-vinylcarbazole, polyacrylamide, etc. are mentioned. Moreover, the polymeric charge transport material mentioned later can also be used. Of these, polyvinyl butyral is often used and is useful. These binder resins may be used alone or as a mixture of two or more.

  The method for forming the charge generation layer is roughly divided into a vacuum thin film preparation method and a casting method from a solution dispersion system.

  The former method includes a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD (chemical vapor deposition) method, and the like. A layer made of the material can be satisfactorily formed.

  In order to provide the charge generation layer by the casting method, the above-described inorganic or organic charge generation material may be ball milled using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone together with a binder resin if necessary. What is necessary is just to disperse | distribute by an attritor, a sand mill, etc., and apply | coat after diluting a dispersion liquid moderately. Among these solvents, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. Application can be performed by dip coating, spray coating, bead coating, or the like.

  The thickness of the charge generation layer provided as described above is usually about 0.01 μm to 5 μm.

  When it is necessary to reduce the residual potential or to increase the sensitivity, these characteristics are often improved by increasing the thickness of the charge generation layer. On the other hand, the chargeability often deteriorates, such as charge charge retention and space charge formation. From these balances, the thickness of the charge generation layer is more preferably in the range of 0.05 μm to 2 μm.

  If necessary, a low molecular compound such as an antioxidant, a plasticizer, a lubricant, and an ultraviolet absorber and a leveling agent can be added to the charge generation layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount used is generally 0.1 phr to 20 phr, preferably 0.1 phr to 10 phr, and the amount used of the leveling agent is suitably about 0.001 phr to 0.1 phr.

-Charge transport layer-
The charge transport layer refers to a part of the laminated photosensitive layer that functions to inject and transport charges generated in the charge generation layer and to neutralize the surface charge of the photoreceptor provided by charging. The main component of the charge transport layer can be referred to as a charge transport component and a binder component that binds the charge transport component.

Examples of the material that can be used for the charge transport material include a low molecular weight electron transport material, a hole transport material, and a polymer charge transport material.
Examples of the electron transporting material include electron accepting materials such as asymmetric diphenoquinone derivatives, fluorene derivatives, naphthalimide derivatives, and the like. These electron transport materials may be used alone or as a mixture of two or more.

  As the hole transport material, an electron donating material is preferably used. Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, butadiene derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, Examples include styryl anthracene, styryl pyrazoline, phenylhydrazones, α-phenyl stilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives. These hole transport materials may be used alone or as a mixture of two or more.

  Moreover, the polymeric charge transport material represented below can be used. For example, a polymer having a carbazole ring such as poly-N-vinylcarbazole, a polymer having a hydrazone structure exemplified in JP-A-57-78402, and JP-A-63-285552 are exemplified. Examples thereof include polysilylene polymers and aromatic polycarbonates exemplified by general formulas (1) to (6) of JP-A No. 2001-330973. These polymer charge transport materials can be used alone or as a mixture of two or more. In particular, the exemplified compounds described in JP-A No. 2001-330973 are useful because of their good electrostatic characteristics.

  Compared with a low molecular charge transport material, the polymer charge transport material has less bleeding of the components constituting the charge transport layer into the cross-linked surface layer when the cross-linked surface layer is laminated on the charge transport layer. It is a material suitable for preventing poor curing of the crosslinked surface layer. In addition, since the charge transport material has a high molecular weight, it is advantageous in that it is less deteriorated by the heat of curing when the crosslinked surface layer is formed because of its excellent heat resistance.

  Examples of the polymer compound that can be used as the binder component of the charge transport layer include polystyrene, polyester, polyvinyl, polyarylate, polycarbonate, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, urethane resin, and phenol. Examples thereof include thermoplastic or thermosetting resins such as resins and alkyd resins. Of these, polystyrene, polyester, polyarylate, and polycarbonate are useful because many of them have good charge transfer characteristics when used as a binder component of a charge transport component. In addition, since the charge transport layer is preferably laminated with a cross-linked surface layer thereon, the charge transport layer is not required to have mechanical strength as compared with the conventional charge transport layer. For this reason, a material such as polystyrene, which has high transparency but a low mechanical strength and is difficult to apply in the prior art, can be effectively used as the binder component of the charge transport layer.

  These polymer compounds can be used singly or as a mixture of two or more kinds, or as a copolymer composed of two or more of these raw material monomers, and further copolymerized with a charge transport material.

  When an electrically inactive polymer compound is used for modifying the charge transport layer, a cardo polymer type polyester having a bulky skeleton such as fluorene, a polyester such as polyethylene terephthalate or polyethylene naphthalate, or a C type polycarbonate A polycarbonate in which the 3,3 ′ portion of the phenol component is alkyl-substituted with respect to a bisphenol-type polycarbonate, a polycarbonate in which the geminal methyl group of bisphenol A is substituted with a long-chain alkyl group having 2 or more carbon atoms, biphenyl Or polycarbonate having a long-chain alkyl skeleton such as polycarbonate having a biphenyl ether skeleton, polycaprolactone, polycaprolactone (for example, described in JP-A-7-292095), acrylic resin, polystyrene, hydrogenation Tajien, or the like is enabled.

  Here, the electrically inactive polymer compound refers to a polymer compound that does not include a chemical structure exhibiting photoconductivity such as a triarylamine structure. When these resins are used in combination with a binder resin as an additive, the amount added is preferably 50% by mass or less based on the total solid content of the charge transport layer, due to restrictions on light attenuation sensitivity.

  When a low molecular charge transport material is used, the amount used is usually 40 phr to 200 phr, preferably about 70 phr to 100 phr. When the polymer charge transporting material is used, a material obtained by copolymerizing the resin component in a proportion of 0 to 200 parts by weight, preferably about 80 to 150 parts by weight with respect to 100 parts by weight of the charge transporting component. Is preferably used.

  In order to satisfy high sensitivity, the charge transport component is preferably added in an amount of 70 phr or more. In addition, α-phenyl stilbene compounds, benzidine compounds, butadiene compound monomers, dimers and polymer charge transport materials having these structures in the main chain or side chain are materials having high charge mobility. Many are useful.

  The charge transport layer can be formed by preparing a charge transport layer coating material by dissolving or dispersing a mixture or copolymer mainly composed of a charge transport component and a binder component in an appropriate solvent, and applying and drying the coating material. . As the coating method, a dipping method, a spray coating method, a ring coating method, a roll coater method, a gravure coating method, a nozzle coating method, a screen printing method, or the like is employed.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating material include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, and aromatics such as toluene and xylene. And the like, halogens such as chlorobenzene and dichloromethane, and esters such as ethyl acetate and butyl acetate. Of these, methyl ethyl ketone, tetrahydrofuran, and cyclohexanone are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These solvents can be used alone or in combination.

  Since the cross-linked surface layer is usually laminated on the upper layer of the charge transport layer, the thickness of the charge transport layer in this configuration is designed to increase the thickness of the charge transport layer in consideration of film scraping in actual use. Is unnecessary. The thickness of the charge transport layer is practically about 10 μm to 40 μm, more preferably about 15 μm to 30 μm for the purpose of ensuring the necessary sensitivity and charging ability.

  Further, if necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge transport layer. These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount used is generally 0.1 phr to 20 phr, preferably 0.1 phr to 10 phr, and the amount used of the leveling agent is suitably about 0.001 phr to 0.1 phr.

<Surface layer>
As the surface layer, a crosslinked surface layer is preferable.
The crosslinked surface layer refers to a protective layer formed on the surface of the photoreceptor. In this protective layer, after coating the coating, a resin having a crosslinked structure is formed by a polymerization reaction of the radical polymerizable material component. Since the resin film has a crosslinked structure, it has the strongest wear resistance among the layers of the photoreceptor. In addition, when a crosslinkable charge transporting structural unit is included, the charge transporting property is similar to that of the charge transporting layer.

-Radically polymerizable material component-
Examples of the radical polymerizable material component include acrylates having an acryloyloxy group.
In the present invention, trimethylolpropane, which is excellent in enhancing the abrasion resistance of the photoreceptor surface, can be preferably used.

  As the trifunctional or higher functional binder component, caprolactone-modified dipentaerythritol hexaacrylate and dipentaerythritol hexaacrylate are preferable. This often improves the wear resistance of the crosslinked film itself or increases the toughness.

As the trifunctional or higher functional radical polymerizable monomer having no charge transport structure, trimethylolpropane triacrylate, caprolactone-modified dipentaerythritol hexaacrylate, and dipentaerythritol hexaacrylate are preferable.
These include those of reagent manufacturers such as Tokyo Kasei Co., Ltd., Nippon Kayaku KAYARD DPCA series, and DPHA series.
In addition, an initiator such as Ciba Specialty Chemicals Irgacure 184 may be added in an amount of about 5% by mass to 10% by mass based on the total solid content in order to accelerate or stabilize the curing.
Examples of the crosslinkable charge transport material include a chain polymerization compound having an acryloyloxy group or a styrene group, a sequential polymerization compound having a hydroxyl group, an alkoxysilyl group, or an isocyanate group, and includes a charge transport structure ( A compound having one or more (meth) acryloyloxy groups can be used.
The crosslinked surface layer may have a composition in combination with a monomer or oligomer having one or more (meth) acryloyloxy groups that do not contain a charge transport structure.
The cross-linked surface layer includes, for example, at least such a compound in the coating liquid, and forms the layer by coating the coating liquid, and is based on radiation such as heat, light, electron beam, and γ-ray. It can be cross-linked and cured by applying energy.
Examples of the compound including the charge transport structure and having one or more (meth) acryloyloxy groups include a charge transport compound represented by the following general formula 1.

However, in the said General formula 1, d, e, and f represent either 0 or 1, respectively. R ₁₃ represents either a hydrogen atom or a methyl group. R <_14> and R < ₁₅ > represent a C1-C6 alkyl group with substituents other than a hydrogen atom, and may differ in the case of multiple. g and h each represent an integer of 0 to 3. Z represents a single bond, a methylene group, an ethylene group, or any of the following structures.

The crosslinked surface layer can be formed, for example, by applying a crosslinked surface layer paint containing the radical polymerizable material component and a solvent.
The solvent used in preparing the crosslinked surface layer coating is preferably a solvent that sufficiently dissolves the monomer. For example, in addition to the above ethers, aromatics, halogens, esters, cellosolve such as ethoxyethanol. And propylene glycols such as 1-methoxy-2-propanol. Of these, methyl ethyl ketone, tetrahydrofuran, cyclohexanone, and 1-methoxy-2-propanol are preferable because they have a lower environmental impact than chlorobenzene, dichloromethane, toluene, and xylene. These solvents can be used alone or in combination.

  Examples of the coating method for the crosslinked surface layer paint include dipping method, spray coating method, ring coating method, roll coater method, gravure coating method, nozzle coating method, and screen printing method. In many cases, since the pot life of the paint is not long, a means capable of coating the required amount with a small amount of paint is advantageous in terms of environmental consideration and cost. Of these, the spray coating method and the ring coating method are preferred.

When the crosslinked surface layer is formed, a UV irradiation light source such as a high-pressure mercury lamp or a metal halide lamp mainly having an emission wavelength in ultraviolet light can be used. In addition, a visible light source can be selected in accordance with the absorption wavelength of the radical polymerizable substance or the photopolymerization initiator. The irradiation light quantity is preferably 50 mW / cm ² or more and 1,000 mW / cm ² or less, and if it is less than 50 mW / cm ² , it takes time for the curing reaction. If it is higher than 1,000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local wrinkles are generated on the surface of the crosslinked surface layer, and many unreacted residues and reaction termination ends are generated. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling.

  If necessary, low-molecular compounds and leveling agents such as antioxidants, plasticizers, lubricants, ultraviolet absorbers and the like described in the charge generation layer, and polymer compounds described in the charge transport layer are added to the crosslinked surface layer. You can also These compounds can be used alone or as a mixture of two or more. When a low molecular weight compound and a leveling agent are used in combination, sensitivity deterioration often occurs. For this reason, the amount used thereof is generally 0.1% to 20% by weight, preferably 0.1% to 10% by weight, and the amount of leveling agent used is 0.1% to 5% in the total solid content of the paint. About mass% is appropriate.

  The thickness of the crosslinked surface layer is suitably about 3 μm to 15 μm. The lower limit is a value calculated from the degree of effect on the film forming cost, and the upper limit is set from electrostatic characteristics such as charging stability and light attenuation sensitivity, and uniformity of film quality.

For the above photoconductor material and toner material, simulation by molecular orbital calculation is reasonable as a material design that satisfies the relationship of the ionization potential of the present invention. The effects of the present invention can be obtained by narrowing down the materials from the calculation results and selecting an appropriate combination.
As a specific calculation example of the photoreceptor material, a calculation example of MOPAC by Komine et al. (See Kotsuki et al., Sharp Technical Report, 76 (2004), 36) is disclosed, and the toner material is an example by Tanaka et al. Academic Journal, 34 (1995), 118) is disclosed, and appropriate materials can be combined in the present invention as well.

<Configuration of image forming apparatus>
Next, one mode for carrying out the image forming method of the present invention by the image forming apparatus of the present invention will be described with reference to the drawings.
The tandem image forming apparatus 100 shown in FIGS. 2 and 3 can be used.
In FIG. 2, an image forming apparatus 100 includes an image writing unit (120Bk, 120C, 120M, 120Y), an image forming unit (130Bk, 130C, 130M, 130Y), and a paper feeding unit for performing color image formation by electrophotography. 140 is mainly composed. Based on the image signal, the image processing unit performs image processing, converts the image forming black (Bk), cyan (C), magenta (M), and yellow (Y) color signals into an image writing unit ( 120Bk, 120C, 120M, 120Y). The image writing unit (120Bk, 120C, 120M, 120Y) is a laser scanning optical system including, for example, a laser light source, a polarizer such as a rotating polygon mirror, a scanning imaging optical system, and a mirror group. The image forming unit (130Bk, 130C, 130M, 130Y) has image writing corresponding to each color signal.

  The image forming unit (130Bk, 130C, 130M, 130Y) includes photoconductors (210Bk, 210C, 210M, 210Y) for black, cyan, magenta, and yellow, and photoconductors (210Bk, 210C, 210M, 210Y) is usually an organic photoreceptor (OPC). Around each of the photoconductors (210Bk, 210C, 210M, 210Y), there are charging devices (215Bk, 215C, 215M, 215Y), and laser light exposure units from the image writing unit (120Bk, 120C, 120M, 120Y). A developing device (200Bk, 200C, 200M, 200Y) for each color, a primary transfer device (230Bk, 230C, 230M, 230Y), a cleaning device (300Bk, 300C, 300M, 300Y), a static eliminator, and the like are arranged. Yes. The developing device (200Bk, 200C, 200M, 200Y) uses a two-component magnetic brush developing system. Further, an intermediate transfer belt (220) is interposed between each photoreceptor (210Bk, 210C, 210M, 210Y) and a primary transfer device (230Bk, 230C, 230M, 230Y), and each intermediate transfer belt 220 is exposed to each photosensitive member. The toner images of the respective colors are sequentially superimposed and transferred from the body to carry the toner images on the respective photosensitive members.

  In some cases, it is preferable that a pre-transfer charger 502 as a pre-transfer charging unit is disposed outside the intermediate transfer belt 220 at a position after passing through the primary transfer position of the final color and before passing through the secondary transfer position. . The pre-transfer charger 502 makes the toner image the same polarity as the toner image before transferring the toner image on the intermediate transfer belt 220 transferred to the photosensitive member 210 in the primary transfer portion onto a transfer sheet as a recording medium. It is charged uniformly.

  The toner image on the intermediate transfer belt 220 transferred from each photoconductor (210Bk, 210C, 210M, 210Y) includes a halftone portion and a solid portion, or includes portions having different amounts of toner overlap. The charge amount may vary. Further, there may be a case where a variation in the charge amount occurs in the toner image on the intermediate transfer belt 220 after the primary transfer due to the peeling discharge generated in the gap adjacent to the downstream side of the primary transfer portion in the intermediate transfer belt moving direction. . Such variation in the charge amount in the same toner image lowers the transfer margin in the secondary transfer portion that transfers the toner image on the intermediate transfer belt 220 onto the transfer paper. Therefore, the toner image before being transferred to the transfer paper by the pre-transfer charger is uniformly charged to the same polarity as the toner image, thereby eliminating the variation in the charge amount in the same toner image and the transfer margin in the secondary transfer portion. Has improved.

  As described above, according to this image forming method, the toner image on the intermediate transfer belt 220 transferred from each photoconductor (210Bk, 210C, 210M, 210Y) is uniformly charged by the pre-transfer charger 502, whereby the intermediate transfer belt 220. Even if there is variation in the charge amount in the upper toner image, the transfer characteristics in the secondary transfer portion can be made substantially constant over the respective portions of the toner image on the intermediate transfer belt 220. Therefore, it is possible to suppress a decrease in transfer margin when transferring to transfer paper and to stably transfer a toner image.

  In this image forming method, the amount of charge charged by the pre-transfer charger varies depending on the moving speed of the intermediate transfer belt 220 that is the object to be charged. For example, if the moving speed of the intermediate transfer belt 220 is slow, the time for the same portion of the toner image on the intermediate transfer belt 220 to pass through the charging region by the pre-transfer charger becomes long, and the charge amount increases. Conversely, when the moving speed of the intermediate transfer belt 220 is fast, the charge amount of the toner image on the intermediate transfer belt 220 becomes small. Therefore, when the moving speed of the intermediate transfer belt 220 changes while the toner image on the intermediate transfer belt 220 passes through the charging position by the pre-transfer charger, the transfer speed depends on the moving speed of the intermediate transfer belt 220. Therefore, it is preferable to control the pre-transfer charger so that the charge amount with respect to the toner image does not change during the process.

  Conductive rollers (241), (242), and (243) are provided between the primary transfer devices (230Bk, 230C, 230M, and 230Y). The transfer sheet is fed from the sheet feeding unit 140 and is then carried on the transfer belt 180 via the registration roller pair 160. When the intermediate transfer belt 220 and the transfer belt 180 come into contact with each other, the secondary transfer roller 170 performs the intermediate transfer. The toner image on the belt 220 is transferred to transfer paper, and color image formation is performed.

  The transfer paper after the image formation is conveyed to the fixing device 150 by the secondary transfer belt 180, and the image is fixed to obtain a color image. The toner on the intermediate transfer belt 220 remaining without being transferred is removed from the belt by the intermediate transfer belt cleaning device 260.

  Since the toner polarity on the intermediate transfer belt 220 before transfer onto the transfer paper is the same negative polarity as that during development, a positive transfer bias voltage is applied to the secondary transfer roller 170, and the toner is transferred onto the transfer paper. The The nip pressure at this portion affects the transfer property and greatly affects the fixability. Further, the toner on the intermediate transfer belt 220 remaining without being transferred is discharged and charged to the positive polarity side and charged to 0 to the positive side at the moment when the transfer paper and the intermediate transfer belt 220 are separated. Note that the toner image formed when the transfer paper is jammed or in the non-image area is not affected by the secondary transfer, and of course remains in the negative polarity.

  Next, the photoconductor cleaning device will be described. In FIG. 2, each developing device (200Bk, 200C, 200M, 200Y) and each cleaning device (300Bk, 300C, 300M, 300Y) are connected to each other by a toner transfer pipe (250Bk, 250C, 250M, 250Y). (Dashed line in FIG. 2). Each toner transfer tube (250Bk, 250C, 250M, 250Y) contains a screw, and the toner collected by each cleaning device (300Bk, 300C, 300M, 300Y) is transferred to each developing device (200Bk). , 200C, 200M, 200Y).

  In the conventional direct transfer method using a combination of the four photosensitive drums and the belt conveyance, paper dust adheres when the photosensitive member comes into contact with the transfer paper, and the toner is collected when the toner is collected. The image was deteriorated such as toner missing and could not be used. Furthermore, in the conventional system combining one photoconductor drum and intermediate transfer, the use of the intermediate transfer member eliminates the adhesion of paper dust to the photoconductor during transfer paper transfer, but recycling of residual toner on the photoconductor In practice, it is practically impossible to separate the mixed color toners. There is also a proposal to use a mixed color toner as a black toner, but even if all the colors are mixed, it does not become black, and the color changes depending on the print mode. Therefore, it is impossible to recycle the toner with one photoconductor configuration.

  On the other hand, in this full-color image forming apparatus, since the intermediate transfer belt 220 is used, paper dust is less mixed and paper dust is prevented from adhering to the intermediate transfer belt 220 during paper transfer. Since each photoconductor (210Bk, 210C, 210M, 210Y) uses independent color toner, it is not necessary to contact or separate each photoconductor cleaning device (300Bk, 300C, 300M, 300Y), and only the toner is reliably collected. can do.

  The positively charged toner remaining on the intermediate transfer belt 220 is cleaned by a conductive fur brush 262 to which a negative voltage is applied. The method of applying a voltage to the conductive fur brush 262 is exactly the same as the conductive fur brush 261 except that the polarity is different. The toner remaining without being transferred is also almost cleaned by the two conductive fur brushes 261 and 262. Here, toner, paper powder, talc, and the like remaining without being cleaned by the conductive fur brush 262 are negatively charged by the negative voltage of the conductive fur brush 262. The next black primary transfer is a transfer with a positive voltage, and negatively charged toner or the like is attracted to the intermediate transfer belt 220 side, so that the transfer to the photoreceptor (black) 210Bk side can be prevented.

  FIG. 3 shows another example of the image forming apparatus used in the image forming method of the present invention, which is a copying apparatus 100 including a tandem indirect transfer type electrophotographic image forming apparatus. In FIG. 3, 110 is a copying apparatus main body, 200 is a paper feed table on which it is placed, 300 is a scanner mounted on the copying apparatus main body 110, and 400 is an automatic document feeder (ADF) further mounted thereon. The copying machine main body 110 is provided with an endless belt-shaped intermediate transfer member 50 at the center.

  As shown in FIG. 3, in this example, the three support rollers 14, 15, and 16 are wound around and can be rotated and conveyed clockwise in the drawing. In the illustrated example, an intermediate transfer body cleaning device 17 that removes residual toner remaining on the intermediate transfer body 50 after image transfer is provided to the left of the second support roller 15 among the three. Among the three images, four images of yellow, cyan, magenta, and black are arranged on the intermediate transfer member 50 stretched between the first support roller 14 and the second support roller 15 along the conveyance direction. The tandem image forming apparatus 120 is configured by arranging the forming units 18 side by side.

  An exposure apparatus 21 is further provided on the tandem image forming apparatus 120 as shown in FIG. On the other hand, a secondary transfer device 22 is provided on the side opposite to the tandem image forming device 120 with the intermediate transfer member 50 interposed therebetween. In the illustrated example, the secondary transfer device 22 is configured by spanning a secondary transfer belt 24, which is an endless belt, between two rollers 23, and presses against the third support roller 16 via an intermediate transfer member 50. The image on the intermediate transfer member 50 is transferred to a sheet. A fixing device 25 for fixing the transfer image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt. The secondary transfer device 22 described above is also provided with a sheet transport function for transporting the image-transferred sheet to the fixing device 25. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device 22, and in such a case, it is difficult to provide this sheet conveyance function together. In the illustrated example, a sheet reversing device 28 for reversing the sheet so as to record an image on both sides of the sheet is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming device 120 described above. Is provided.

  Now, when making a copy using this color electrophotographic image forming apparatus, the document is set on the document table 130 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it.

  When the start switch is pressed, when a document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then when the document is set on the other contact glass 32, Immediately, the scanner 300 is driven, and the first traveling body 33 and the second traveling body 34 travel. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When the start switch is pressed, one of the support rollers 14, 15, and 16 is driven to rotate by the drive motor, the other two support rollers are driven to rotate, and the intermediate transfer body 50 is rotated and conveyed. At the same time, the individual image forming means 18 rotates the photoconductor 10 to form monochrome images of black, yellow, magenta, and cyan on each photoconductor 10. Then, along with the conveyance of the intermediate transfer member 50, these single color images are sequentially transferred to form a composite color image on the intermediate transfer member 50.

  On the other hand, when the start switch is pressed, one of the paper feed rollers 142 of the paper feed table 200 is selectively rotated, the sheet is fed out from one of the paper cassettes 144 provided in multiple stages in the paper bank 143, and one sheet is fed by the separation roller 145. The paper is separated and put into the paper feed path 146, transported by the transport roller 147, guided to the paper feed path 148 in the copying machine main body 100, and abutted against the registration roller 49 and stopped.

  Alternatively, the sheet feed roller is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 58, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.

  Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 50, the sheet is fed between the intermediate transfer member 50 and the secondary transfer device 22, and is transferred by the secondary transfer device 22. A color image is recorded on the sheet.

  The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the switching roller 55 is used to switch the discharge image. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.

  On the other hand, the intermediate transfer member 50 after image transfer is removed by the intermediate transfer member cleaning device 17 to remove residual toner remaining on the intermediate transfer member 50 after image transfer, and is prepared for re-image formation by the tandem image forming device 120. Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

(Process cartridge)
The process cartridge of the present invention comprises at least a photosensitive member carrying an electrostatic latent image and developing means for developing the electrostatic latent image carried on the photosensitive member using toner to form a visible image. And other means such as a charging means, an exposure means, a transfer means, a cleaning means, and a static elimination means, which are appropriately selected as necessary.
The toner of the present invention is used as the toner.

The developing means includes at least a developer container that contains the toner or developer, and a developer carrier that carries and transports the toner or developer contained in the developer container. In addition, a layer thickness regulating member for regulating the thickness of the toner layer carried on the developer carrying member may be provided. Specifically, any one of the one-component developing unit and the two-component developing unit described in the image forming apparatus and the image forming method can be preferably used.
Further, as the charging unit, the exposure unit, the transfer unit, the cleaning unit, and the charge removal unit, the same ones as those of the above-described image forming apparatus can be appropriately selected and used.
The process cartridge can be detachably provided in various electrophotographic image forming apparatuses, facsimiles, and printers, and it is particularly preferable that the process cartridge is detachably provided in the image forming apparatus of the present invention.

  An example of the process cartridge of the present invention is shown in FIG. The process cartridge 800 shown in FIG. 4 includes a photoreceptor 801, a charging unit 802, a developing unit 803, and a cleaning unit 806.

  The operation of the process cartridge 800 will be described. The photosensitive member 801 is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member 801 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the charging unit 802, and then receives image exposure light from an image exposure unit such as slit exposure or laser beam scanning exposure, In this way, electrostatic latent images are sequentially formed on the peripheral surface of the photoconductor 801. The formed electrostatic latent image is then converted into a toner image by the developing means 802. The developed toner image is transferred from the paper feeding unit to the photoconductor. The image is sequentially transferred by the transfer means to the recording medium fed in synchronization with the rotation of the photosensitive member 801 between the transfer means 801 and the transfer means. The recording medium that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor 801 after the image transfer is cleaned by the removal of the transfer residual toner by the cleaning unit 806, and after being further discharged, it is repeatedly used for image formation.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”.

First, a method for producing toner used for image formation in Examples and Comparative Examples will be described below.
(Production of toner)
-Synthesis of amorphous polyester resin A1-
A mixture of 3-methyl-1,5-pentanediol and trimethylolpropane in a molar ratio of 97: 3 (alcohol component) and adipic acid (acid component) in a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction pipe ) Was added together with titanium tetraisopropoxide (300 ppm to resin component) so that OH: COOH = 1.1: 1. Thereafter, the temperature was raised to 200 ° C. in about 4 hours, and then the temperature was raised to 230 ° C. over 2 hours until the effluent water disappeared.
Then, it was made to react under reduced pressure of 10-15 mmHg for 5 hours, and intermediate polyester was obtained.
Next, the intermediate polyester and isophorone diisocyanate were charged at a molar ratio of 2.1: 1 into a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and diluted with ethyl acetate to 48 wt%. Then, it was made to react at 100 degreeC for 5 hours, and amorphous polyester resin A1 which has a reactive group was obtained.
The number average molecular weight (Mn) of this resin was 3,800, the weight average molecular weight (Mw) was 17,500, and Tg was −50 ° C.

-Synthesis of amorphous polyester resin A2-
Mixture of 85:15 molar ratio of bisphenol A ethylene oxide side 2 mol adduct and bisphenol A propylene oxide 3 mol adduct in a 5 L four neck flask equipped with nitrogen inlet tube, dehydration tube, stirrer and thermocouple (Alcohol component) and a mixture of 80:20 molar ratio of isophthalic acid and adipic acid (acid component) were charged at OH: COOH = 1.3: 1, and at 230 ° C. under normal pressure with 500 ppm of titanium tetraisopropoxide. For 10 hours, and further for 5 hours under reduced pressure of 10 to 15 mmHg. Then, 30 parts of trimellitic anhydride is added to the reaction vessel and reacted at 180 ° C. under normal pressure for 3 hours to obtain an amorphous polyester resin. A2 was obtained. The number average molecular weight (Mn) of this resin was 2,400, the weight average molecular weight (Mw) was 5,400, and Tg was 48 ° C.

-Synthesis of crystalline polyester resin B-
In a heat-dried two-necked flask, a mixture of 90:10 molar ratio of dimethyl fumarate and dimethyl sebacate (acid content), 1.15 times as much acid component as 1,6-hexanediol (alcohol component), and catalyst Then, Ti (OBu) 4 was added, and then the air in the container was made an inert atmosphere of nitrogen gas by depressurization and refluxed at 180 ° C. for 5 hours by mechanical stirring. Thereafter, excess 1,6-hexanediol was removed by distillation under reduced pressure, and the mixture was stirred for 2 hours while gradually raising the temperature to 230 ° C., and when it became viscous, it was air-cooled to stop the reaction. Before the product solidified, tetrahydrofuran (THF) was added into the reaction vessel, and the catalyst residue was removed with a pressure filter. For purification, the reprecipitate was collected using THF / MeOH and dried under reduced pressure to obtain a crystalline polyester resin B having an unsaturated double bond. The number average molecular weight (Mn) of this resin was 3,900, the weight average molecular weight (Mw) was 13,800, and the melting point was 68 ° C.

-Synthesis of ketimine compounds-
170 parts of isophorone diamine and 75 parts of methyl ethyl ketone were charged into a reaction vessel equipped with a stir bar and a thermometer, and reacted at 50 ° C. for 5 hours to obtain a ketimine compound having an amine value of 418.
-Preparation of masterbatch (MB)-
A mixture having the following composition was kneaded with two rolls at 150 ° C. for 30 minutes, then rolled and cooled, and pulverized with a pulverizer to obtain a master batch.
Carbon black: 44 parts (Printex 35, manufactured by Degussa) [DBP oil absorption = 42 mL / 100 mg, pH = 9.5]
Amorphous polyester resin A1: 100 parts Amorphous polyester resin A2: 1,100 parts Water: 200 parts

-Preparation of pigment / WAX dispersion-
A mixture having the following composition was charged into a container equipped with a stirring bar and a thermometer, heated to 80 ° C. with stirring, held at 80 ° C. for 5 hours, and then cooled to 30 ° C. in 1 hour.
-Crystalline polyester resin B having an unsaturated double bond: 220 parts-Paraffin wax: 50 parts (Nippon Seiki Co., Ltd., HNP-9, hydrocarbon wax, melting point 75 ° C., SP value 8.8)
CCA (salicylic acid metal complex E-84, manufactured by Orient Chemical Industries): 23 parts Ethyl acetate: 947 parts

Next, the container was charged with materials having the following composition and mixed for 1 hour to obtain a raw material solution.
-Master batch: 500 parts-Ethyl acetate: 500 parts 1,324 parts of the above raw material solution was transferred to a container and dispersed using a bead mill under the following conditions.
(Distribution condition)
・ Liquid feeding speed: 1kg / hr
・ Disk peripheral speed: 6 m / sec ・ Dispersion media: φ0.5 mm zirconia beads 80% by volume filling ・ Number of passes: 3 times

Next, 1042 parts of a 65% ethyl acetate solution of amorphous polyester resin A was added, and one pass was performed with a bead mill under the same conditions as described above to obtain a pigment / WAX dispersion.
The solid content concentration of this pigment / WAX dispersion was 50%.

-Preparation of oil phase-
-Pigment-WAX dispersion: 664 parts-Polyester resin A1: 80 parts-Ketimine compound: 4.6 parts The following materials are put in a container and mixed at 5,000 rpm for 1 minute with a TK homomixer (manufactured by Tokushu Kika). Thus, an oil phase was obtained.

-Synthesis of organic fine particle emulsion-
The following materials were charged in a reaction vessel equipped with a stirrer and a thermometer, and stirred at 400 rpm for 15 minutes to obtain a white emulsion.
-Water: 683 parts-Sodium salt of methacrylic acid ethylene oxide adduct sulfate: 11 parts (Eleminol RS-30, manufactured by Sanyo Chemical Industries)
-Styrene: 138 parts-Methacrylic acid: 138 parts-Ammonium persulfate: 1 part The white emulsion was heated to increase the temperature in the system to 75 ° C and reacted for 5 hours.
Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours. A fine particle dispersion] was obtained.
A part of the fine particle dispersion was dried to isolate the resin component.

-Preparation of aqueous phase-
The following materials were mixed and stirred to obtain a milky white liquid. This was the aqueous phase.
Water: 990 parts Fine particle dispersion: 83 parts

-Emulsification / solvent removal-
To the container containing the [oil phase], 1,200 parts of an aqueous phase was added and mixed with a TK homomixer at a rotational speed of 13,000 rpm for 20 minutes to obtain an emulsified slurry.
The emulsified slurry was put into a container equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 8 hours.

-Unsaturated group reaction process-
A catalyst amount of a water-soluble radical polymerization initiator (V-44 manufactured by Wako Pure Chemical Industries, Ltd.) was added to the obtained slurry after solvent removal, and then aging was carried out at 50 ° C. for 5 hours. Heavy bonds were reacted to obtain a dispersed slurry.

-Cleaning and drying-
After 100 parts of the dispersion slurry was filtered under reduced pressure, the following operations (1) to (5) were performed.
(1): 100 parts of ion-exchanged water was added to the filter cake, and the TK homomixer was mixed at a rotational speed of 12,000 rpm for 10 minutes, followed by filtration.
(2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer at 12,000 rpm for 10 minutes, and then filtered.
(4): 300 parts of ion-exchanged water is added to the filter cake of (3), and the mixture is mixed with a TK homomixer at a rotational speed of 12,000 rpm for 10 minutes, and then filtered (1) to (3). The operation of was performed twice to obtain a filter cake.
(5): The filter cake of (4) was dried at 45 ° C. for 48 hours with a circulating dryer, and sieved with a mesh of 75 μm to obtain a toner.
The toner obtained above is hereinafter referred to as “toner A”.

[Example 1]
The following intermediate layer coating solution was applied to an aluminum support (outer diameter φ60 mm) by an immersion method to form an intermediate layer. The film thickness of the intermediate layer after drying at 170 ° C. for 30 minutes was 5 μm.

(Intermediate layer coating solution)
-Zinc oxide particles (MZ-300, manufactured by Teika Co., Ltd.): 350 parts-1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H , 3H, 5H) -trione: 1.5 parts (Karenz (registered trademark) MT NR1, manufactured by Showa Denko KK)
Blocked isocyanate: 60 parts (Sumijoule (registered trademark) 3175, solid content concentration 75% by mass, manufactured by Sumika Bayer Urethane Co., Ltd.)
-20% by mass of a butyral resin dissolved in 2-butanone: 225 parts (BM-1, manufactured by Sekisui Chemical Co., Ltd.)
2-butanone: 365 parts On the obtained intermediate layer, the following charge generation layer coating solution was dip coated to form a charge generation layer. The film thickness of the charge generation layer was 0.2 μm.

(Coating solution for charge generation layer)
-Y-type titanyl phthalocyanine: 6 parts-Butyral resin (ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.): 4 parts-2-butanone (manufactured by Kanto Chemical): 200 parts A charge transport layer was formed by dip coating the coating layer coating solution. The film thickness of the charge transport layer after drying at 135 ° C. for 20 minutes was 22 μm.

(Coating liquid for charge transport layer)
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
・ Low molecular charge transport material represented by the following structural formula: 10 parts

-Tetrahydrofuran: 80 parts On the obtained charge transport layer, the following coating solution for a cross-linked surface layer was spray-coated in a nitrogen stream, and then left to stand in a nitrogen stream for 10 minutes to dry touch. Thereafter, light irradiation was performed in a UV irradiation booth in which the inside of the booth was replaced with nitrogen gas so that the oxygen concentration was 2% or less.

(Surface layer)
Furthermore, it was dried at 130 ° C. for 20 minutes to obtain a photoreceptor of Example 1. The film thickness of the surface layer of the crosslinked resin was 4.5 μm.
(Light irradiation conditions)
・ Metal halide lamp: 160 W / cm
・ Irradiation distance: 120mm
・ Irradiation intensity: 700 mW / cm ²
・ Irradiation time: 60 seconds (cross-linked resin surface layer coating solution)
Trimethylolpropane triacrylate: 5 parts (KAYARAD TMPTA, Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical polymerizable compound having no charge transporting structure)
Dipentaerythritol caprolactone-modified hexaacrylate: 5 parts (KAYARAD DPCA-120, manufactured by Nippon Kayaku, acrylic equivalent 324)
-Radical polymerizable compound having a monofunctional charge transport structure of the following structural formula (acryl equivalent 420): 10 parts

1-hydroxy-cyclohexyl-phenyl-ketone: 1 part
(Irgacure 184, manufactured by Ciba Specialty Chemicals, photopolymerization initiator)
・ Tetrahydrofuran: 100 parts

After the photoconductor of Example 1 produced as described above was used for mounting, it was mounted on a black developing station of an electrophotographic apparatus (Ricoh Pro C751EX, manufactured by Ricoh), and a print image was obtained using toner A. .
A3 size copy of image data in which half-tone images are output in order, with a solid rectangular pattern including white characters in the first and second rotation of the photosensitive drum starting development, and an independent dot pattern for every two dots. Printed out on paper (My Paper A3, NBS Ricoh). The pixel density was 1200 dpi × 1200 dpi.

[Example 2]
A photoconductor of Example 2 was obtained in the same manner as in Example 1 except that the charge transport material of the charge transport layer coating solution was changed to a compound represented by the following structural formula.
A print image was obtained using the photoreceptor of Example 2 and toner A.

[Example 3]
The photosensitivity of Example 3 is the same as that of Example 1 except that the radical polymerizable compound having a monofunctional charge transporting structure in the cross-linked resin surface layer coating solution is changed to a compound represented by the following structural formula. Got the body.
A print image was obtained using the photoreceptor of Example 3 and toner A.

[Example 4]
A photoconductor of Example 4 was obtained in the same manner as in Example 3, except that the charge transport material in the charge transport layer coating solution was changed to a compound represented by the following structural formula.
A print image was obtained using the photoreceptor of Example 4 and toner A.

[Example 5]
A printed image was obtained in the same manner as in Example 1 except that the toner used in Example 1 was replaced with a genuine Ricoh Pro C7110 cyan toner.

[Example 6]
A printed image was obtained in the same manner as in Example 1 except that the toner used in Example 1 was changed to a genuine magenta toner for Ricoh Pro C7110.

[Example 7]
A print image was obtained in the same manner as in Example 1 except that the toner used in Example 1 was changed to a genuine Ricoh Pro C751EX magenta toner.

[Example 8]
The photoconductor of Example 8 was prepared in the same manner as in Example 1 except that the radical polymerizable compound having a monofunctional charge transporting structure in the cross-linked resin surface layer coating solution was changed to a compound represented by the following structural formula. Got. A printed image was obtained in the same manner as in Example 1 except that this photoreceptor and the toner used in Example 1 were replaced with genuine Ricoh Pro C751EX magenta toner.

[Example 9]
A photoconductor of Example 9 was obtained in the same manner as in Example 1 except that the coating liquid for charge transport layer and the coating liquid for the surface-crosslinked resin surface layer in Example 1 were changed to the following.
(Coating liquid for charge transport layer)
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
・ Low molecular charge transport material represented by the following structural formula: 10 parts
・ Tetrahydrofuran: 80 parts ・ Silicone oil 0.002 parts (KF-50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

(Coating liquid for surface layer)
-Bisphenol Z-type polycarbonate: 53 parts (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
・ Low molecular charge transport material represented by the following structural formula: 37 parts
Α-alumina (Sumicorundum AA-03, manufactured by Sumitomo Chemical Co., Ltd.): 32 parts Dispersant (BYK-P105, manufactured by Big Chemie): 0.4 parts Tetrahydrofuran: 2000 parts Cyclohexanone: 600 parts

The charge transport layer was heat-dried at 135 ° C. for 20 minutes after dip coating. The average film thickness of the charge transport layer was 20 μm. The surface layer coating solution was spray-coated on the obtained charge transport layer and then dried by heating at 150 ° C. for 20 minutes. The average film thickness of the surface layer was 5 μm.
A print image was obtained in the same manner as in Example 1 except that the above-described photoreceptor and the toner used in Example 1 were replaced with genuine Ricoh Pro C751EX magenta toner.

[Example 10]
Example 1 except that the intermediate layer, charge generation layer, and charge transport layer of Example 1 were dip coated as the following coating solution to change to a 5 μm intermediate layer, 1 μm charge generation layer, and 20 μm charge transport layer. In the same manner as in Example 1, a photoreceptor of Example 10 was obtained. A printed image was obtained in the same manner as in Example 1 except that this photoreceptor and the toner used in Example 1 were replaced with genuine Ricoh Pro C751EX magenta toner.

(Interlayer coating solution)
・ Titanium oxide: 30 parts (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.)
・ Titanium oxide: 10 parts (PT-401M, manufactured by Ishihara Sangyo Co., Ltd.)
-Alkyd resin: 8 parts (Beckolite M6401-50, solid content: 50%, manufactured by DIC Corporation)
Melamine resin (G-821-60, solid content: 60%, manufactured by DIC): 5 parts 2-butanone: 54 parts

(Coating solution for charge generation layer)
-Asymmetric disazo pigment represented by the following structural formula (Y): 24 parts
-Metal-free phthalocyanine pigment: 12 parts-Polyvinyl butyral (Butver-B90): 7 parts-Cyclohexanone: 625 parts-2-Butanone: 330 parts

(Coating liquid for charge transport layer)
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals Ltd.)
・ Low molecular charge transport material represented by the following structural formula: 10 parts
・ Tetrahydrofuran: 80 parts ・ Silicone oil (KF-50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.): 0.002 parts

  On the obtained charge transport layer, the following coating solution for a cross-linked surface layer was spray-coated in a nitrogen stream, and then left in a nitrogen stream for 10 minutes to dry the touch. Thereafter, light irradiation was performed in a UV irradiation booth in which the inside of the booth was replaced with nitrogen gas so that the oxygen concentration was 2% or less.

(Surface layer)
Furthermore, it was dried at 130 ° C. for 20 minutes to obtain a photoreceptor of Example 1. The film thickness of the surface layer of the crosslinked resin was 4.5 μm.
(Light irradiation conditions)
・ Metal halide lamp: 160W / cm
・ Irradiation distance: 120mm
・ Irradiation intensity: 700 mW / cm ²
・ Irradiation time: 60 seconds

(Crosslinked resin surface layer coating solution)
Trimethylolpropane triacrylate: 5 parts (KAYARAD TMPTA, Nippon Kayaku Co., Ltd., acrylic equivalent 99, trifunctional or higher functional radical polymerizable compound having no charge transporting structure)
Dipentaerythritol caprolactone-modified hexaacrylate 5 parts (KAYARAD DPCA-120, manufactured by Nippon Kayaku, acrylic equivalent 324)
-Radical polymerizable compound having a monofunctional charge transporting structure represented by the following structural formula (acryl equivalent 420): 10 parts
1-hydroxy-cyclohexyl-phenyl-ketone: 1 part
(Irgacure 184, manufactured by Ciba Specialty Chemicals, photopolymerization initiator)
・ Tetrahydrofuran: 100 parts

[Example 11]
A photoconductor was obtained in the same manner as in Comparative Example 4 except that the intermediate layer of Comparative Example 3 was changed to the intermediate layer of Example 1. A printed image was obtained in the same manner as in Example 1 except that this photoreceptor and the toner used in Example 1 were replaced with genuine Ricoh Pro C751EX magenta toner.

[Comparative Example 1]
A photoconductor of Comparative Example 1 was obtained in the same manner as in Example 1 except that the radical polymerizable compound having a monofunctional charge transporting structure was changed to a compound represented by the following structural formula.
A print image was obtained using the photoreceptor of Comparative Example 1 and toner A.

[Comparative Example 2]
A printed image was obtained in the same manner as in Example 1 except that the toner used in Example 1 was replaced with a genuine Ricoh Pro C751EX black toner.

[Comparative Example 3]
The photoconductor of Comparative Example 4 was prepared in the same manner as in Example 1 except that the radical polymerizable compound having a monofunctional charge transporting structure in the cross-linked resin surface layer coating solution was changed to a compound represented by the following structural formula. Got. A printed image was obtained in the same manner as in Example 1 except that this photoreceptor and the toner used in Example 1 were replaced with genuine Ricoh Pro C751EX magenta toner.

(Evaluation method)
For each image forming apparatus, negative afterimages at halftone portions were evaluated after outputting 1 million images of an original with an image area ratio of 6%. The conditions of the image forming apparatus were adjusted so that the conditions were uniform.
・ Primary transfer current: 35μA
-Photoconductor charging potential: -600v
・ Development bias: -500v
-Toner density in developer: 8.4 ± 0.1%
Development γ: 1.3 ± 0.1 (mg / cm ² ) / − kV
The development γ represents the magnitude of the slope of a portion that is linearly approximated among the curves representing the relationship between the difference between the photoreceptor potential and the development bias and the toner adhesion amount.

The afterimage was evaluated in the following five stages.
5 ························································································· 4 It is generated but it is at the allowable limit 1 ... It is clearly generated and cannot be allowed

(Ionization potential measurement method)
The photoconductor was measured by measuring an ionization potential measuring device (20 mm square in the center in the drum axis direction) obtained by coating and drying an intermediate layer, a charge generation layer, a charge transport layer, and a crosslinked resin surface layer on a conductive support having a diameter of 60 mm. PYS-202, manufactured by Sumitomo Heavy Industries, Ltd.).
The toner was measured using a circular aluminum container having a diameter of 20 mm that received the toner powder.

  In order to measure the ionization potential of each layer of the photoreceptor, when measuring the ionization potential of the charge transport layer formed on the inner side of the photoreceptor surface composed of the crosslinked resin surface layer, the crosslinked resin surface layer is polished with a wrapping film. What was made into the state which the charge transport layer exposed completely was used for the measurement. For measuring the ionization potential of the charge generation layer, the charge transport layer was peeled off and the deposit of the charge generation material remaining on the intermediate layer was used as a sample for measuring the ionization potential of the charge generation layer. Further, for measuring the ionization potential of the intermediate layer, a sample obtained by washing the surface of the intermediate layer to which the charge generating material adheres with methyl ethyl ketone and drying was used as a sample. Further, after immersing the conductive support remaining in the intermediate layer in a mixed solvent of methyl ethyl ketone and tetrahydrofuran for 2 days, removing the intermediate layer with cotton and evaporating the solvent used for washing, measuring the ionization potential of the conductive support A sample was used. Separately from the above, a conductive support, and a sample on which the single layer film of the charge generation layer or charge transport layer is the outermost surface were prepared on the conductive support, and the ionization potential was measured. No results were obtained. However, since the apparent ionization potential increases when the conductive support is allowed to stand for a long time, it was measured immediately after cleaning the surface.

The photocurrent during monochromatic light exposure through a monochromator was measured using a xenon lamp for the conductive support and the intermediate layer of the photoreceptor, and a D2 lamp as the light source for the other layers. The photoelectron yield is calculated by dividing the number of photons in the irradiated light. A power source was provided between the ground and the sample, and a bias of −100 V was applied to the sample. Measurement conditions were measured under vacuum conditions of 1 × 10 ⁻² Pa. Photoelectron yield is measured using the control / analysis software attached to the ionization potential measurement device, and the relationship between the total electron yield of photoelectrons and the cube root of the total electron yield of photoelectrons is graphed with spreadsheet software (Microsoft Excel). The energy value at the intersection of two approximate lines with respect to the curve drawn in this manner was taken as the ionization potential. The approximate straight line can be drawn in accordance with the conventional practice as illustrated in FIG. Depending on how the approximate straight line is drawn, the ionization potential will slightly fluctuate. However, if the conditions of the present invention are satisfied within the range of such fluctuation, there will be no problem in the invention effect.

Tables 1 and 2 show the measurement results of the ionization potential and the image evaluation results.

It is considered that a negative afterimage is caused by a local variation in charging characteristics of the photosensitive member. In particular, as the speed of the electrophotographic process increases, the image forming process continues in a shorter time than the time when the photoreceptor uniformly relaxes, and the history of the photoreceptor is accumulated. . In the electrophotographic process, the photosensitive member is charged not only negatively but also positively in transfer. It is desirable that the charge to reach a predetermined charged potential of both polarities is stocked between the electrodes and in the bulk by the photoconductor but is not accumulated locally.
The photoconductor of Example 1 has a smaller ionization potential difference between the intermediate layer and the charge generation layer than the photoconductor of Comparative Example 1, and it is considered that charge accumulation at this interface is difficult. This is considered to have been effective in suppressing negative afterimages.

  The cause of the difference in charging characteristics locally on the photoconductor may be the influence of toner developed on the photoconductor. It is considered that charging of the photosensitive member and charge injection by the transfer means are shielded by this toner. The toner of Example 1 has a smaller ionization potential difference on the surface of the photoconductor than the toner of Comparative Example 3, and this relationship seems to weaken the previous shielding effect. For this reason, it is thought that the effect which suppresses a negative afterimage has arisen.

When Example 1 was compared with Example 2, Example 1 was one rank, and the result which was excellent in the negative afterimage was obtained. The photoconductor of Example 1 has a different slope of the baseline of the spectrum obtained by measuring the ionization potential on the surface of the photoconductor. Example 1 has a slope of zero, while Example 2 has a slight slope. The reason why the baseline is inclined is that the fluctuation of the energy level of the hopping site that gives charge transport is large. This seems to temporarily accumulate charges as a light trapping site, and this is thought to have affected negative afterimages.
The same relationship is seen in Example 3 and Example 4.

  The photoconductors of Examples 1 to 11 have a higher ionization potential on the surface of the photoconductor than Comparative Example 1. This property is considered to suppress the deterioration of the surface of the photoreceptor. For this reason, it seems that the change in chargeability is suppressed even for printing with a large volume. This is thought to contribute to the suppression of negative afterimages.

It is desirable that the uniformity of the surface potential of the photoreceptor after the transfer process is less affected by the presence of toner. For this reason, it is advantageous that the ionization potential on the surface of the photoconductor is lower as a relationship in which an electrostatic barrier is suppressed at the interface between the toner and the photoconductor. On the other hand, if the ionization potential on the surface of the photoconductor is too low, the chemical stability is impaired, and as a result, the afterimage characteristics are adversely affected. Example 1 and Comparative Example 3 and Comparative Example 1 show this relationship. Therefore, it can be said that the scope of the present invention is particularly advantageous for the afterimage characteristics.
In the present invention, as shown in the Examples or Comparative Examples, the effect of the present invention is equally recognized for the charge generating material, the charge transporting material, the photoconductor having different surface layer materials, and various toners, and the versatile practical value is excellent. It is a thing.

(About Figure 2)
100 Image forming apparatus 120Bk, 120C, 120M, 120Y Image writing unit 130Bk, 130C, 130M, 130Y Image forming unit 140 Paper feeding unit 200Bk, 200C, 200M, 200Y Developing devices 210Bk, 210C, 210M, 210Y Photoconductors 215Bk, 215C , 215M, 215Y Charging device 230Bk, 230C, 230M, 230Y Primary transfer device 300Bk, 300C, 300M, 300Y Cleaning device

(About Figure 3)
10K black photoconductor 10Y yellow photoconductor 10M magenta photoconductor 10C cyan photoconductor 14, 15, 16 support roller 17 intermediate transfer cleaning device 18 image forming means 21 exposure device 22 secondary transfer device 23 roller 25 fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 49 Registration roller 50 Intermediate transfer body 51 Manual feed tray 53 Manual feed path 55 Switching claw 56 Discharge Roller 57 Discharge tray 100 Image forming apparatus 110 Copier apparatus main body 120 Tandem image forming apparatus 130 Document table 142 Paper feed roller 143 Paper bank 144 Paper feed cassette 145 Separating roller 146 Paper feed path 147 Conveyance low Over 148 feeding path 200 feed table 220 intermediate transfer belt 300 Scanner 400 automatic document feeder

(About Figure 4)
800 Process cartridge 801 Photoconductor 802 Charging means 803 Developing means 804 Developer 806 Cleaning means

JP 2005-165229 A Japanese Patent Laid-Open No. 5-289458 Japanese Patent No. 3331219 JP-A-5-173460 JP-A-7-234618 JP 2001-350329 A

Claims (7)

An image forming method for forming an image using a photoreceptor having at least an intermediate layer and a photosensitive layer formed by laminating a charge generation layer and a charge transport layer on a conductive support,
An image forming method, wherein the relationship between the ionization potential on the surface of the photoreceptor and the ionization potential on the toner surface satisfies the following formulas (1) and (2):
| Ip (photosensitive member surface) −Ip (toner) | ≦ 0.18 [eV] (1)
5.45 [eV] ≦ Ip (photosensitive member surface) ≦ 5.53 [eV] (2)
(here,
Ip (photoconductor surface) represents the ionization potential of the photoconductor surface,
Ip (toner) represents the ionization potential on the toner surface. )   When the photoreceptor is irradiated with monochromatic light in the ultraviolet region on the surface of the photoreceptor and the cubic root of the total electron yield of the emitted photoelectrons is plotted as a function of incident light energy, the resulting spectrum has the lowest incidence. The slope of the baseline (approximate straight line on the low energy side) is 0 out of the approximate straight line of the total electron yield to the incident light energy before and after the rising point of the light energy side curve (threshold differentiated as ionization potential). The image forming method according to claim 1, wherein the photosensitive member is:   3. The image forming method according to claim 1, wherein the photosensitive layer comprises a plurality of layers of two or more layers, and an ionization potential difference between adjacent layers is 0.30 eV or less.   The photosensitive layer includes a charge generation layer and a charge transport layer, and an ionization potential difference between the charge generation layer and the charge transport layer is 0.05 eV or less. Image forming method.   The image forming method according to claim 1, wherein the intermediate layer contains zinc oxide. An image forming apparatus using the image forming method according to claim 1.
A process cartridge using the image forming method according to claim 1.