JP2014142538A - Image carrier protective agent, protective layer forming device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image carrier protective agent that has all the performance of prevention of abrasion, filming, and damage to an image carrier, prevention of contamination of charging means, and cleanability.SOLUTION: An image carrier protective agent contains a fatty acid metal salt, inorganic lubricant, and melamine-formaldehyde resin particles. An aspect in which the melamine-formaldehyde resin particles have the volume average particle diameter of 0.5 μm or less, and an aspect in which the melamine-formaldehyde resin particles have the volume average particle diameter of 0.1 μm to 0.4 μm, and the like are preferable.

Description

  The present invention relates to an image carrier protecting agent, a protective layer forming apparatus, and an image forming apparatus.

Conventionally, in image formation by an electrophotographic method, an image carrier containing a photoconductive substance or the like (hereinafter sometimes referred to as “photosensitive member”, “electrophotographic photosensitive member”, or “electrostatic latent image carrier”). An electrostatic latent image is formed thereon, and a charged toner is attached to the electrostatic latent image to form a visible image. The visible image formed with the toner is finally transferred onto a recording medium such as paper, and then fixed on the recording medium with heat, pressure, solvent, gas, etc., and becomes an output image.
Such an electrophotographic image forming method is a method of charging a toner for visualization, a two-component development method using frictional charging by stirring and mixing of a toner and a carrier, and without using a carrier. It is roughly classified into a one-component development system that applies charge to toner.
The one-component development method is classified into a magnetic one-component development method and a non-magnetic one-component development method depending on whether or not a magnetic force is used to hold toner on the developing roller.

Up to now, copiers that require high speed and image reproducibility, and multi-function machines based on these, have two-component development due to demands such as toner charging stability, start-up stability, and long-term image quality stability. Many methods are adopted. On the other hand, one-component development systems are often used in small printers, facsimiles, and the like that have great demands for space saving and cost reduction.
In particular, in recent years, colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever. In order to improve the image quality, the average particle diameter of the toner is reduced, and the particle shape has no angular portion, resulting in a rounder spherical shape.

  The electrophotographic image forming apparatus is generally charged uniformly while rotating a drum-shaped or belt-shaped image bearing member, regardless of the development method, and on the image bearing member by a laser beam or the like. Then, a latent image pattern is formed, and this is visualized by developing means, and further transferred onto a recording medium. The toner that has not been transferred remains on the image carrier after the toner image is transferred to the recording medium. If the remaining toner is conveyed to the charging process as it is, uniform charging of the image carrier may be hindered. For this reason, generally, after passing through the transfer step, the toner remaining on the image carrier is removed in a cleaning step, and the surface of the image carrier is sufficiently cleaned, and then charging is performed. .

As described above, the surface of the image bearing member is subjected to various physical stresses and electrical stresses in each process such as a charging process, a developing process, a transfer process, and a cleaning process, and the surface state changes with the use time. . Among these stresses, the stress due to friction in the cleaning process has a problem that the image carrier is worn and scratches are generated.
In order to eliminate the above-mentioned problems, an image carrier protective agent, a method for supplying a lubricating component, a molding method for the protective agent, and a protective film have been used so far to reduce the frictional force between the image carrier and the cleaning blade. Many proposals have been made on the formation method and the like (for example, see Patent Documents 1 to 5). However, none of these proposals satisfy all the performances of image carrier wear, prevention of filming and scratches, prevention of contamination of charging means, and cleaning.

An image forming unit comprising: an image forming unit having an image holding member; and a cleaning unit having a cleaning blade in contact with the image holding member, wherein a lubricant is applied to a portion where the cleaning blade comes into contact with the image holding member. In Japanese Patent Application Laid-Open No. H10-260707, it is proposed that the lubricant contains a melamine-formaldehyde condensate (see Patent Document 6).
However, in this proposal, the melamine-formaldehyde condensate is used alone as the lubricant, and the lubricant is directly applied to the portion where the cleaning blade contacts the image carrier. There are problems that the image carrier is worn, filming and scratches are prevented, the charging means is prevented from being contaminated, and the cleaning property is deteriorated when a large amount of data is output continuously.

  Therefore, it is desired to provide an image carrier protecting agent that has all the performances of preventing wear, filming and scratches of the image carrier, preventing contamination of the charging means, and cleaning properties.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an image carrier protecting agent that has all the performances of preventing wear, filming and scratches of the image carrier, preventing contamination of the charging means, and cleaning properties.

  The image carrier protecting agent of the present invention as a means for solving the above problems contains a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles.

  According to the present invention, it is possible to solve the above-described problems, and to protect the image carrier having all of the performances of wear of the image carrier, prevention of filming and scratches, prevention of contamination of the charging means, and cleaning properties. An agent can be provided.

FIG. 1 is a schematic view showing an example of a protective layer forming apparatus of the present invention. FIG. 2 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 3 is a schematic view showing an example of a process cartridge used in the present invention.

(Image carrier protective agent)
The image carrier protecting agent of the present invention contains a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles, and further contains other components as necessary.

  When general organic fine particles have a volume average particle size of 1.0 μm or less, aggregation tends to occur and it is difficult to maintain a particle state on the order of submicrons. However, the melamine-formaldehyde resin particles used in the present invention are less likely to aggregate even if the volume average particle size is 1.0 μm or less, and can take advantage of the characteristics while maintaining a submicron order particle size. . This makes it possible to exert a uniform and fine polishing effect on the inorganic lubricant laminated on the image carrier, and since the organic fine particles are softer than alumina or the like, the surface of the image carrier is It will not hurt. As a result, it is presumed that the image bearing member can have all of the performances of prevention of wear, filming and scratches, prevention of contamination of the charging means, and cleaning property.

<Melamine-formaldehyde resin particles>
The melamine-formaldehyde resin in the melamine-formaldehyde resin particles is a thermosetting resin produced by polycondensation of melamine and formaldehyde, and is also referred to as “melamine-formaldehyde condensate” or “melamine resin”.
The melamine-formaldehyde resin particles are sandwiched between objects and play a role of rollers, but the melamine-formaldehyde resin particles themselves are a stable material that does not cause internal slip and cleavage like an inorganic lubricant. is there.

There is no restriction | limiting in particular in the average molecular weight of the said melamine-formaldehyde resin particle, Although it can select suitably according to the objective, 100-5,000 are preferable at a weight average molecular weight.
There is no restriction | limiting in particular as a volume average particle diameter of the said melamine-formaldehyde resin particle, Although it can select suitably according to the objective, 0.5 micrometer or less is preferable and 0.1 micrometer-0.4 micrometer are more preferable. When the volume average particle size is less than 0.1 μm, the toner and the external additive of the toner are likely to pass through the cleaning blade, which may affect the cleaning property, the contamination of the charging unit, and the protection of the image carrier. If it exceeds 0.5 μm, cleaning failure due to coarse particles may occur.
Examples of the method for measuring the volume average particle size include a method using a laser scattering / diffraction type particle size measuring device (Microtrack MT3000II, manufactured by Nikkiso Co., Ltd.).

There is no restriction | limiting in particular as said melamine formaldehyde resin particle, What was synthesize | combined suitably may be used and a commercial item may be used. Examples of the method for synthesizing the melamine-formaldehyde resin particles include a method of producing by melamine produced from urea as a raw material and polycondensation of formaldehyde.
As said commercial item, brand name: S-6 (made by Nippon Shokubai Co., Ltd.) etc. are mentioned, for example.

There is no restriction | limiting in particular as content in the said image carrier protective agent of the said melamine-formaldehyde resin particle, Although it can select suitably according to the objective, 2 mass%-30 mass% are preferable, and 5 mass%- 20 mass% is more preferable.
When the content is less than 2% by mass, a sufficient polishing effect cannot be obtained with respect to the inorganic lubricant laminated on the photoconductor, and the protection of the photoconductor may be deteriorated. If it exceeds 50%, the melamine-formaldehyde resin itself is not sufficiently removed by the cleaning blade, and the cleaning property may be deteriorated.

<Inorganic lubricant>
The inorganic lubricant is a compound that cleaves and lubricates itself or causes internal slip.
The inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose.For example, mica, boron nitride, molybdenum disulfide, tungsten disulfide, talc, kaolin, montmorillonite, calcium fluoride, graphite, Etc. These may be used individually by 1 type and may use 2 or more types together. Of these, boron nitride and mica are preferred, and hexagonal mesh surfaces with tightly assembled atoms overlap at wide intervals, and only the weak van der Waals force connects the layers, so the layers can be easily cleaved. In view of lubrication, boron nitride is particularly preferable.

The average primary particle size of the inorganic lubricant is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.1 μm to 10 μm. In the preferable numerical range, it is possible to improve the cleaning property and prevent filming on the image carrier.
The average primary particle size of the inorganic lubricant is, for example, an image observed with a scanning electron microscope (SEM) (thermal F-SEM, manufactured by Zeiss, ULTRA55), image analysis / measurement software (Image-pro plus 4. 0j, manufactured by Media Cybernetics), and can be measured by taking the average of 10 of them.

  There is no restriction | limiting in particular as said inorganic lubricant, A commercial item can be used. Examples of the commercially available products include boron nitride (manufactured by Saint-Gobain, IDL, average primary particle size 0.6 μm), mica (manufactured by Topy Industries, Ltd., PDM-5B, average primary particle size 6 μm), and the like. .

  There is no restriction | limiting in particular as content in the said image carrier protective agent of the said inorganic lubricant, Although it can select suitably according to the objective, 2 mass%-50 mass% are preferable, and 5 mass%-20 mass. % Is more preferable. If the content is less than 2% by mass, the amount of film formation decreases, contamination of the charging means may occur, and the cleaning property may decrease. If the content exceeds 50% by mass, the protection of the photoreceptor decreases. May end up.

<Fatty acid metal salt>
The fatty acid metal salt is not particularly limited and may be appropriately selected depending on the intended purpose. For example, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, stearin Strontium acid, calcium stearate, cadmium stearate, magnesium stearate, zinc stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, zinc palmitate, Cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprylate, lead caprate, zinc linolenate, cobalt linolenate, calcium linolenate, ricino Le zinc, cadmium ricinoleate, zinc laurate, cobalt laurate, lauric lead, magnesium laurate, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, zinc stearate, calcium stearate, and zinc laurate are preferable, zinc stearate because it is a very stable substance that is excellent in cleaning properties and photoconductor protection, inexpensive, and hydrophobic. Is particularly preferred.

The mass ratio between the fatty acid metal salt and the inorganic lubricant (fatty acid metal salt / inorganic lubricant) is not particularly limited and may be appropriately selected depending on the intended purpose, but is 98/2 to 85/15. Preferably, 95/5 to 90/10 is more preferable. When the mass ratio of the fatty acid metal salt is larger than the range of the mass ratio (fatty acid metal salt / inorganic lubricant), the amount of film formation decreases, the contamination of the charging means may occur, and the cleaning property may be deteriorated. On the other hand, when the ratio of the inorganic lubricant is larger than the range of the mass ratio (fatty acid metal salt / inorganic lubricant), the protection of the photoreceptor may be lowered.
When the mass ratio (fatty acid metal salt / inorganic lubricant) is within a preferable numerical range, the film forming property is improved while the content of expensive boron nitride is reduced, the charging means is not contaminated, the cleaning property and the photoconductor. There is an advantage that the protective property of is improved.

<Other ingredients>
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, resin fine particles other than a melamine-formaldehyde resin particle, inorganic fine particles, surfactant, a dispersing agent, etc. are mentioned.

The method for molding the image carrier protecting agent of the present invention into a fixed shape, for example, a prismatic or cylindrical shape, is not particularly limited, and a known method can be used as a method for molding a solid substance, For example, a compression molding method, a melt molding method, a powder molding method, a cold isostatic pressing method (CIP), a hot isostatic pressing method (HIP), and the like can be given. Among these, the compression molding method is particularly preferable from the viewpoint of easy cutting of the molded body.
In the compression molding method, a mixture of a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles is placed in a mold of a predetermined size, and then compression molded at a predetermined pressure and time, and after cooling. The solid can be removed from the mold to obtain a molded body. Thereafter, the shape of the image carrier protecting agent may be adjusted by cutting or the like.

There is no restriction | limiting in particular as said formwork, Although it can select suitably according to the objective, Metal formwork, such as steel materials, stainless steel, and aluminum, from the good heat conductivity and the good dimensional accuracy is preferable. The inner wall surface of the mold is preferably coated with a release agent such as a fluororesin or a silicone resin in order to improve the releasability.
The produced block-shaped image carrier protecting agent is used by being bonded to a base material such as a metal, an alloy, or plastic with an adhesive or the like.

  Since the image carrier protecting agent of the present invention has all the performances of image carrier wear, filming and scratching prevention, charging means contamination prevention, and cleaning performance, the protective layer forming apparatus described below Can be suitably used.

(Protective layer forming device)
The protective layer forming apparatus of the present invention includes the image carrier protective agent of the present invention and an image carrier protective agent supply member, preferably a protective layer forming member, and further, if necessary, pressing force It has other members, such as a provision member.

The image carrier protecting agent supply member is a member that supplies the image carrier protecting agent of the present invention to the surface of the image carrier.
The protective layer forming member is a member that forms a protective layer on the surface of the image carrier by pressing the image carrier protective agent of the present invention supplied to the image carrier.
The pressing force applying member is a member that presses the image carrier protecting agent of the present invention and presses it against the image carrier protecting agent supply member.

  In the case where the protective layer forming member is provided in the protective layer forming apparatus, the protective layer forming member may also serve as a cleaning unit. However, in order to more reliably form the protective layer, an image carrier is previously formed by the cleaning unit. It is preferable to remove the residue mainly composed of the toner above so that the residue does not enter the protective layer.

Here, FIG. 1 is a schematic view showing an example of the protective layer forming apparatus of the present invention.
The protective layer forming apparatus 2 disposed opposite to the photosensitive drum as the image carrier 1 includes an image carrier protective agent 21, a protective agent supply member 22, a pressing force applying member 23, and a protective layer forming member of the present invention. 24.

The image carrier protecting agent 21 of the present invention is in contact with, for example, a brush-like protecting agent supply member 22 by the pressing force from the pressing force applying member 23. The protective agent supply member 22 rotates and rubs with the image carrier 1 with a linear velocity difference. At this time, the image carrier protective agent 21 held on the surface of the protective agent supply member 22 is supplied to the surface of the image carrier 1. To do.
Since the image carrier protecting agent 21 supplied to the surface of the image carrier 1 may not be a sufficient protective layer at the time of supply depending on the selection of the material type, in order to form a more uniform protective layer, for example, The protective layer forming member 24 having a blade-like member is thinned to form a protective layer.

  The image bearing member on which the protective layer is formed is, for example, in a minute gap by bringing the charging roller 3 to which a DC voltage or a voltage obtained by superimposing an AC voltage is applied with a high voltage power source (not shown) into contact or in proximity. The image carrier 1 is charged by discharging. At that time, a part of the protective layer is decomposed or oxidized by electrical stress. In addition, the air discharge product adheres to the surface of the protective layer.

  The deteriorated image carrier protecting agent is removed by the cleaning unit together with other components such as toner remaining on the image carrier 1 by a normal cleaning unit. Such a cleaning means may be used also as the protective layer forming member 24. However, the function of removing the residue on the surface of the image carrier and the function of forming the protective layer are based on the state of rubbing the appropriate member. Therefore, it is preferable to provide a cleaning unit 4 including a cleaning member 41 and a cleaning pressing mechanism 42 on the upstream side of the image carrier protecting agent supply unit as shown in FIG. .

  There is no restriction | limiting in particular as a material of the braid | blade used for the said protective layer formation member 24, According to the objective, it can select suitably, For example, urethane rubber, hydrin rubber, silicone rubber, fluororubber etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. In these rubber blades, the contact portion with the image carrier may be coated or impregnated with a low friction coefficient material. Moreover, in order to adjust the hardness of an elastic body, you may disperse fillers, such as an organic filler and an inorganic filler.

The blade is fixed to the blade support by any method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. There is no restriction | limiting in particular about the thickness of the said blade, Although it differs according to balance with the force added by press and cannot be defined uniquely, 0.5 mm-5 mm are preferable and 1 mm-3 mm are more preferable.
Also, the length of the cleaning blade that protrudes from the blade support and can be deflected, that is, the so-called free length, is not unambiguously defined in consideration of the force applied by pressing in the same manner. Preferably, 2 mm to 10 mm is more preferable.

  Other configurations of the blade include a method of coating, dipping, etc. a coating layer of resin, rubber, elastomer, etc. on the surface of an elastic metal blade such as a spring plate, if necessary, via a coupling agent, a primer component, etc. It may be formed by heat curing or the like if necessary, and surface polishing or the like may be applied if necessary.

The coating layer contains at least a binder resin and a filler, and further contains other components as necessary.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include fluorine resins such as PFA, PTFE, FEP and PVDF; silicone elastomers such as fluorine rubber and methylphenyl silicone elastomer. , Etc.

  There is no restriction | limiting in particular in the thickness of the said elastic metal braid | blade, Although it can select suitably according to the objective, 0.05 mm-3 mm are preferable and 0.1 mm-1 mm are more preferable. In the elastic metal blade, in order to suppress twisting of the metal blade, a process such as bending may be performed in a direction substantially parallel to the support shaft after attachment.

  The force that presses the image carrier 1 with the protective layer forming member 24 is sufficient as the force that the image carrier protective agent extends to become a protective layer or a protective film, and there is no particular limitation on the linear pressure. Although it can be appropriately selected according to the purpose, it is preferably 5 gf / cm or more and 80 gf / cm or less, more preferably 10 gf / cm or more and 60 gf / cm or less.

A brush-like member is preferably used as the protective agent supply member 22. In this case, in order to suppress mechanical stress on the surface of the image carrier, it is preferable that the brush fiber has flexibility. There is no restriction | limiting in particular as a material of the said flexible brush fiber, According to the objective, it can select suitably, For example, polyolefin resin (for example, polyethylene, polypropylene, etc.); polyvinyl resin or polyvinylidene resin (For example, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, etc.); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer Styrene-butadiene resin; fluororesin (eg, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc.); polyester; nylon; acrylic; rayon; Polyurethane; polycarbonate; phenolic resins; amino resins (eg, urea - formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, polyamide resins, etc.), and the like.
In order to adjust the degree of bending, the resin includes, for example, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, and the like. Can be used in combination.

The support for the protective agent supply member 22 includes a fixed mold and a rotatable roll. Examples of the roll-shaped supply member include a roll brush obtained by winding a tape having brush fibers piled around a metal core bar in a spiral shape. The brush fiber has a fiber diameter of about 10 μm to 500 μm, the length of the brush fiber is 1 mm to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ⁷ to 4 per square meter). .5 × 10 ⁸ ) is preferable.

  The protective agent supply member 22 is preferably made of a material having a high brush density in terms of supply uniformity and supply stability, and one fiber is made from several to several hundreds of fine fibers. It is also preferable to do. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

Moreover, you may provide a coating layer in the said brush surface for the purpose of stabilizing the surface shape of a brush, environmental stability, etc. as needed. As the component constituting the coating layer, it is preferable to use a coating layer component that can be deformed according to the bending of the brush fiber.
The coating layer component is not particularly limited as long as it is a material that can maintain flexibility, and can be appropriately selected according to the purpose. Examples thereof include polyethylene, polypropylene, chlorinated polyethylene, and chlorosulfonated polyethylene. Polyolefin resins; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polybiliketones, and other polyvinyl or polyvinylidene resins; Vinyl acetate copolymer; silicone resin composed of organosiloxane bond or modified product thereof (for example, modified product by alkyd resin, polyester resin, epoxy resin, polyurethane, etc.); Fluororesin such as cycloalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamide; polyester; polyurethane; polycarbonate; amino resin such as urea-formaldehyde resin; epoxy resin or composite resin thereof Can be mentioned.

(Image forming method and image forming apparatus)
The image forming method used in the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a protective layer forming step, and other steps appropriately selected as necessary, for example, a cleaning step. A fixing process, a charge eliminating process, a recycling process, a control process, and the like.
The image forming apparatus according to the present invention includes at least an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a protective layer forming unit, and other components appropriately selected as necessary. For example, a cleaning means, a fixing means, a charge eliminating means, a recycling means, a control means and the like.

  The image forming method used in the present invention can be preferably implemented by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming unit, and the developing step can be The transfer step can be performed by the transfer unit, the protective layer forming step can be performed by the protective layer forming unit, and the other steps can be performed by the other unit. Can do.

<Electrostatic latent image forming step and electrostatic latent image forming means>
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the image carrier, and can be performed by an electrostatic latent image forming unit.

<< Image carrier >>
The image carrier (hereinafter sometimes referred to as “electrostatic latent image carrier” or “photosensitive member”) is not particularly limited in terms of its material, shape, structure, size, etc. From the above, it is possible to appropriately select a drum shape.

The image carrier is not particularly limited and may be appropriately selected depending on the intended purpose. However, the image carrier has a support and at least a photosensitive layer on the support, and other layers as necessary. What has this is suitable.
In order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the image carrier, a surface layer may be provided on the photosensitive layer. An undercoat layer can be provided between the photosensitive layer and the support.

<<< Support >>>
The support is not particularly limited as long as it has a volume resistivity of 1.0 × 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. For example, aluminum, nickel , Metal such as chromium, nichrome, copper, gold, silver, platinum, metal oxide such as tin oxide, indium oxide, etc. by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or aluminum, Plates made of aluminum alloy, nickel, stainless steel, and the like, and pipes that have been surface-treated by cutting, superfinishing, polishing, or the like after being formed into a drum shape by extruding, drawing or the like can be used.

The drum-shaped support preferably has a diameter of 20 mm to 150 mm, more preferably 24 mm to 100 mm, and still more preferably 28 mm to 70 mm. When the diameter of the drum-shaped support is less than 20 mm, it may be physically difficult to arrange each step of charging, exposure, development, transfer, and cleaning around the drum. When the diameter exceeds 150 mm, The image forming apparatus may become large. In particular, when the image forming apparatus is a tandem type, since it is necessary to mount a plurality of photoconductors, the diameter is preferably 70 mm or less, more preferably 60 mm or less.
Further, an endless nickel belt or an endless stainless steel belt as disclosed in JP-A-52-36016 can also be used as the conductive support.

<<< Photosensitive layer >>>
The photosensitive layer may have any of a single layer structure and a laminated structure composed of a charge generation layer and a charge transport layer, but a photosensitive layer having a multilayer structure composed of a charge generation layer and a charge transport layer is particularly preferred.
First, the laminated photosensitive layer will be described.
The photosensitive layer having the laminated structure is configured by sequentially laminating a charge generation layer and a charge transport layer.

-Charge generation layer-
The charge generation layer contains at least a charge generation material, preferably contains a binder resin, and further contains other components as necessary.

-Charge generation material-
The charge generating material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, azo pigments such as monoazo pigments, disazo pigments, asymmetric disazo pigments, trisazo pigments, titanyl phthalocyanine, copper phthalocyanine, vanadyl phthalocyanine Phthalocyanine pigments such as hydroxygallium phthalocyanine and metal-free phthalocyanine, perylene pigments, perinone pigments, indigo pigments, pyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squalium pigments, etc. It is done. These may be used individually by 1 type and may use 2 or more types together.

--Binder resin--
There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, a polyamide resin, a polyurethane resin, an epoxy resin, a polyketone resin, a polycarbonate resin, a silicone resin, an acrylic resin, a polyvinyl butyral resin, polyvinyl Formal resin, polyvinyl ketone resin, polystyrene resin, polysulfone resin, poly-N-vinyl carbazole resin, polyacrylamide resin, polyvinyl benzal resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene Examples thereof include oxide resins, polyamide resins, polyvinyl pyridine resins, polyvinyl alcohol resins, polyvinyl pyrrolidone resins, cellulose resins, and caseins. These may be used individually by 1 type and may use 2 or more types together.
The content of the binder resin is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 500 parts by mass or less, and 10 parts by mass to 300 parts by mass with respect to 100 parts by mass of the charge generation material. Is more preferable.

The charge generation layer is a charge generation layer coating solution obtained by dissolving or dispersing the charge generation material in a solvent together with the binder resin, if necessary, using a dispersion method such as a ball mill, an attritor, a sand mill, or an ultrasonic wave. It can be formed by coating on the support, or undercoat layer or intermediate layer and drying. The binder resin may be added before or after the charge generating material is dispersed.
The solvent is not particularly limited and may be appropriately selected depending on the intended purpose.For example, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, mono Examples include chlorobenzene, cyclohexane, toluene, xylene, ligroin, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, ketone solvents, ester solvents, and ether solvents are particularly preferable.

The charge generation layer coating solution contains the charge generation material, and preferably contains a solvent and a binder resin, but optionally contains additives such as a sensitizer, a dispersant, a surfactant, and silicone oil. It may be.
The method for forming the charge generation layer using the charge generation layer coating liquid is not particularly limited and may be appropriately selected depending on the intended purpose. For example, dip coating, spray coating, bead coating, nozzle coating, Examples include spinner coats and ring coats.
There is no restriction | limiting in particular in the average thickness of the said charge generation layer, Although it can select suitably according to the objective, 0.01 micrometer-5 micrometers are preferable, and 0.1 micrometer-2 micrometers are more preferable. After coating, it is heated and dried in an oven or the like. There is no restriction | limiting in particular as a drying temperature of the said charge generation layer, Although it can select suitably according to the objective, 50 to 160 degreeC is preferable.

-Charge transport layer-
The charge transport layer contains a charge transport material and a binder resin, and further contains other components as necessary.

-Charge transport layer-
Examples of the charge transport material include a hole transport material and an electron transport material.
The hole transport material is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include poly-N-vinylcarbazole or a derivative thereof, poly-γ-carbazolylethyl glutamate or a derivative thereof, and pyrene. -Formaldehyde condensate or derivative thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivative, oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, Benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives , Pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.

There is no restriction | limiting in particular as said electron transport material, According to the objective, it can select suitably, For example, chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1 , 2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, benzoquinone derivatives, and the like. These may be used individually by 1 type and may use 2 or more types together.
The content of the charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 parts by mass to 300 parts by mass, and 40 parts by mass to 150 parts by mass with respect to 100 parts by mass of the binder resin. Part by mass is more preferable.

--Binder resin--
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester , Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinyl carbazole) ), Acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The charge transport layer is formed by applying a charge transport layer coating solution in which the charge transport material and the binder resin are dissolved or dispersed in a solvent on a charge generation layer, a support, or an undercoat layer, and then drying. It is formed. You may add additives, such as a plasticizer, a leveling agent, antioxidant, a lubricant, to the said charge transport layer coating liquid as needed.

  Examples of the solvent include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, non-halogen solvents are preferable from the viewpoint of reducing environmental burdens, and cyclic ethers such as tetrahydrofuran, dioxolane, and dioxane; aromatic hydrocarbons such as toluene and xylene, or derivatives thereof are particularly preferable.

The application method is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a dip coating method, a spray coating method, a bead coating method, a nozzle coating method, a spinner coating method, and a ring coating method. Can be mentioned. Among these, the dip coating method is preferable because the charge transport layer needs to be thickened to some extent.
The formed charge transport layer is heated and dried by a heating means such as an oven. There is no restriction | limiting in particular in drying temperature, Although it can select suitably according to the objective, 80 to 200 degreeC is preferable and 110 to 170 degreeC is more preferable. There is no restriction | limiting in particular in drying time, Although it can select suitably according to the objective, 10 minutes or more are preferable and 20 minutes or more are more preferable.
The average thickness of the charge transport layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 μm to 50 μm, more preferably 15 μm to 35 μm from the viewpoint of resolution and responsiveness.

<<< Single-layer photosensitive layer >>>
The photosensitive layer having a single layer structure is a photosensitive layer in which a charge generation material and a charge transport material are dispersed or dissolved in a binder resin to realize a charge generation function and a charge transport function in one layer.

For the charge generation material, charge transport material, binder resin, solvent, and various additives used for the single layer photosensitive layer, any material contained in the charge generation layer and the charge transport layer is used. It is possible.
The charge transport material preferably contains both the hole transport material and the electron transport material. A plasticizer, a leveling agent, an antioxidant and the like can be added as necessary.
As the binder resin, in addition to the binder resin mentioned in the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. The content of the charge generating material with respect to 100 parts by mass of the binder resin is not particularly limited and can be appropriately selected according to the purpose, but is preferably 5 parts by mass to 40 parts by mass, and 10 parts by mass to 30 parts by mass. More preferred. The content of the charge transport material is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0 part by mass to 190 parts by mass, and more preferably 50 parts by mass to 150 parts by mass.

The photosensitive layer having the single layer structure comprises a coating solution obtained by dissolving or dispersing the charge generation material, the charge transport material, and the binder resin in a solvent such as tetrahydrofuran, dioxane, dichloroethane, methyl ethyl ketone, cyclohexane, cyclohexanone, toluene, xylene. It can be formed by coating using a dip coating method, spray coating, bead coating, ring coating or the like.
There is no restriction | limiting in particular in the average thickness of the photosensitive layer of the said single layer structure, Although it can select suitably according to the objective, 5 micrometers-40 micrometers are preferable, and 10 micrometers-30 micrometers are more preferable.

<<< undercoat layer >>>
The undercoat layer of the photoconductor may be composed of one layer or a plurality of layers. For example, (1) the resin is the main component, and (2) the white pigment and the resin are the main components. And (3) a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate. Among these, those containing a white pigment and a resin as main components are preferable.
Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among these, it is particularly preferable to contain titanium oxide that is excellent in preventing charge injection from the conductive substrate.
Examples of the resin include thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose; thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy. These may be used individually by 1 type and may use 2 or more types together.
There is no restriction | limiting in particular in the average thickness of the said undercoat layer, Although it can select suitably according to the objective, 0.1 micrometer-10 micrometers are preferable, and 1 micrometer-5 micrometers are more preferable.

<<< Surface layer >>>
The surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning properties, etc. of the photoreceptor. As the surface layer, a polymer having a mechanical strength higher than that of the photosensitive layer, or an inorganic filler dispersed in the polymer is suitable.
The resin used for the surface layer may be either a thermoplastic resin or a thermosetting resin, but the thermosetting resin has a high mechanical strength and is extremely capable of suppressing wear due to friction with the cleaning blade. It is particularly preferable because it is high. If the surface layer is thin, there is no problem even if it does not have the charge transport capability, but if the surface layer having no charge transport capability is formed thick, the sensitivity of the photoreceptor is decreased, the potential increases after exposure, and the residual layer remains. Since it is easy to cause a potential increase, it is preferable to use the above-mentioned charge transporting substance in the surface layer, or to use a polymer having a charge transporting capability for the polymer used in the surface layer.

When the surface layer is provided, the mechanical strength of the photosensitive layer and the surface layer is generally greatly different, so the surface layer is worn away due to friction with the cleaning blade and disappears immediately. Therefore, it is important that the surface layer has a sufficient thickness.
There is no restriction | limiting in particular in the average thickness of the said surface layer, Although it can select suitably according to the objective, 0.1 micrometer-12 micrometers are preferable, 1 micrometer-10 micrometers are more preferable, and 2 micrometers-8 micrometers are still more preferable. When the average thickness is less than 0.1 μm, it is too thin and easily disappears due to friction with the cleaning blade, and wear of the photosensitive layer may proceed from the disappeared portion, and when it exceeds 12 μm. In addition, a decrease in sensitivity, an increase in potential after exposure, and an increase in residual potential are likely to occur. In particular, when a polymer having charge transport capability is used, the cost of the polymer having charge transport capability may increase.

  The resin used for the surface layer is preferably one that is transparent to the writing light at the time of image formation and excellent in insulation, mechanical strength, and adhesiveness. For example, ABS resin, ACS resin, olefin-vinyl monomer Copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin , Polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin, Etc., and the like. These polymers may be thermoplastic resins, but in order to increase the mechanical strength of the polymers, they are crosslinked with a crosslinking agent having a polyfunctional acryloyl group, carboxyl group, hydroxyl group, amino group, etc. By doing so, the mechanical strength of the surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

  The surface layer preferably has a charge transport capability. In order to give the surface layer a charge transport capability, a method of using a mixture of the polymer used for the surface layer and the above-described charge transport material, charge transport A method of using a polymer having capability for the surface layer is conceivable, and the latter method is preferable because it can obtain a photoconductor with high sensitivity and little increase in potential after exposure and little increase in residual potential.

  Examples of the polymer having the charge transport layer ability include groups represented by the following general formula (i) as the group having the charge transport ability in the polymer.

<General formula (i)>
However, in the general formula (i), Ar ¹ represents a substituted or unsubstituted arylene group. Ar ² and Ar ³ may be the same as or different from each other, and represent a substituted or unsubstituted aryl group.

The group having the charge transporting ability is preferably added to a side chain of a polymer having high mechanical strength such as polycarbonate resin and acrylic resin, and the monomer is easy to produce and is excellent in coating property and curability. Resins are particularly preferred.
The acrylic resin having such a charge transporting capability is a surface layer having high mechanical strength, excellent transparency, and high charge transporting capability by polymerizing the unsaturated carboxylic acid having the group of the general formula (i). By mixing a polyfunctional unsaturated carboxylic acid, preferably a tri- or higher functional unsaturated carboxylic acid, with a monofunctional unsaturated carboxylic acid having the group of the general formula (i). The resin forms a crosslinked structure, becomes a thermosetting polymer, and the mechanical strength of the surface layer is extremely high. Although the group of the general formula (i) may be added to the polyfunctional unsaturated carboxylic acid, since the production cost of the monomer becomes high, the polyfunctional unsaturated carboxylic acid includes the general formula ( It is preferable to use a photocurable polyfunctional monomer without adding the group i).

  Examples of the monofunctional unsaturated carboxylic acid having a group of the general formula (i) include the following general formula (ii) or general formula (iii).

<General formula (ii)>

<General Formula (iii)>

In the general formulas (ii) and (iii), R ₁ has a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (wherein R ₇ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, Or an aryl group which may have a substituent), a carbonyl halide group, CONR ₈ R ₉ (wherein R ₈ and R ₉ may be the same as or different from each other, a hydrogen atom, Represents a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent.
In the general formula (ii) and the general formula (iii), Ar ₁ and Ar ₂ may be the same as or different from each other, and represent a substituted or unsubstituted arylene group.
In the general formula (ii) and the general formula (iii), Ar ₃ and Ar ₄ may be the same as or different from each other, and represent a substituted or unsubstituted aryl group.
In the general formulas (ii) and (iii), X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, sulfur. Represents an atom or vinylene group.
In the general formulas (ii) and (iii), Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
m and n each represent an integer of 0 to 3.

In the general formula (ii) and general formula (iii), examples of the alkyl group in the substituent of R ₁ include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include halogen atoms, nitro groups, cyano groups; alkyl groups such as methyl groups and ethyl groups; alkoxy groups such as methoxy groups and ethoxy groups; aryloxy groups such as phenoxy groups; aryl groups such as phenyl groups and naphthyl groups; It may be substituted with an aralkyl group such as a benzyl group or a phenethyl group. Of these R ₁ substituents, a hydrogen atom or a methyl group is particularly preferred.

The substituted or unsubstituted Ar ₃ and Ar ₄ are an aryl group, and examples of the aryl group include a condensed polycyclic hydrocarbon group, a non-fused cyclic hydrocarbon group, and a heterocyclic group.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.
Examples of the non-condensed cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether, and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as diphenylalkyne, triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane and polyphenylalkene; rings such as 9,9-diphenylfluorene And monovalent groups of aggregated hydrocarbon compounds.
Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

There is no restriction | limiting in particular in content of the said polyfunctional unsaturated carboxylic acid, Although it can select suitably according to the objective, 5 mass%-75 mass% of the whole said surface layer are preferable, 10 mass%-70 % By mass is more preferable, and 20% by mass to 60% by mass is even more preferable. When the content is less than 5% by mass, the mechanical strength of the surface layer is insufficient, and when it exceeds 75% by mass, cracks are likely to occur when a strong force is applied to the surface layer, resulting in sensitivity deterioration. May also occur.
When an acrylic resin is used for the surface layer, after applying the unsaturated carboxylic acid to the photoreceptor, electron beam irradiation or actinic rays such as ultraviolet rays are irradiated to cause radical polymerization to form the surface layer. be able to. When performing radical polymerization with actinic rays, a solution obtained by dissolving a photopolymerization initiator in an unsaturated carboxylic acid is used. As the photopolymerization initiator, materials used for photocurable paints can be used.

Metal or metal oxide fine particles can be dispersed in the surface layer in order to increase the mechanical strength of the surface layer. There is no restriction | limiting in particular as said metal oxide, According to the objective, it can select suitably, For example, a titanium oxide, a tin oxide, potassium titanate, TiO, TiN, a zinc oxide, an indium oxide, an antimony oxide, etc. Can be mentioned.
As the other components, a fluororesin such as polytetrafluoroethylene, a silicone resin, or a resin in which an inorganic material is dispersed can be added for the purpose of improving wear resistance.

  In the image carrier, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, it is preferable to prevent oxidation on each layer such as a charge generation layer, a charge transport layer, an undercoat layer, and a surface layer. An agent, a plasticizer, a lubricant, an ultraviolet absorber, a low molecular charge transport material, a leveling agent, and the like can be added.

  Next, the formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the image carrier and then performing imagewise exposure, and by the electrostatic latent image forming unit. Can do. The electrostatic latent image forming unit includes, for example, at least a charger that uniformly charges the surface of the image carrier and an exposure unit that exposes the surface of the image carrier imagewise.

The charging can be performed, for example, by applying a voltage to the surface of the image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The charger preferably has voltage applying means for applying a voltage having an AC component.

The exposure can be performed, for example, by exposing the surface of the image carrier imagewise using the exposure device.
The exposure device is not particularly limited as long as it can perform image-like exposure on the surface of the image carrier charged by the charger, and can be appropriately selected according to the purpose. Examples include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using toner or the developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

<< Toner >>
The toner is not particularly limited and may be appropriately selected depending on the intended purpose. The average circularity, which is the average value of the circularity SR represented by the following formula 1, is preferably 0.93 to 1.00. 0.95-0.99 is more preferable. The average circularity is an index of the degree of unevenness of toner particles, and indicates 1.00 when the toner is a perfect sphere, and the average circularity becomes smaller as the surface shape becomes more complicated.
<Formula 1>
Circularity SR = (perimeter of circle having the same area as the projected area of toner particles) / (perimeter of projected image of toner particles)

  When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the toner particles and the contact area between the toner particles and the photosensitive member are small, so that the transferability is excellent. Further, since the toner particles have no corners, the developer agitation torque in the developing device is small, and the agitation drive is stabilized, so that no abnormal image is generated. In addition, since there are no angular toner particles in the toner that forms the dots, the pressure is uniformly applied to the entire toner that forms the dots when pressed against the recording medium during transfer, and the transfer is not easily lost. Further, since the toner particles are not angular, the abrasive power of the toner particles themselves is small, and the surface of the photoreceptor is not damaged or worn.

The circularity SR can be measured as follows using, for example, a flow type particle image analyzer (manufactured by Sysmex Corporation, FPIA-1000).
First, 0.1 mL to 0.5 mL of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 mL to 150 mL of water from which impure solids have been previously removed, and 0.1 g of a measurement sample is further added. Add ~ 0.5g. The suspension in which the sample is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the dispersion concentration is set to 3,000 / μL to 10,000 / μL. Measure.

  The weight average particle diameter (D4) of the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 3 μm to 10 μm, and more preferably 4 μm to 8 μm. In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent. When the weight average particle diameter (D4) is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties may occur. When the weight average particle diameter (D4) exceeds 10 μm, scattering of characters and lines can be suppressed. It can be difficult.

  In the toner, the ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) is not particularly limited and can be appropriately selected according to the purpose. -1.40 is preferable, and 1.00-1.30 is more preferable. The closer the ratio (D4 / D1) is to 1.00, the sharper the particle size distribution of the toner. In the range of the ratio (D4 / D1) of 1.00 to 1.40, the toner Since the selective development due to the average particle size of the toner does not occur, the image quality is excellent. In addition, since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp and the occurrence of fog is suppressed. In addition, when the toner particle diameters are uniform, the latent image dots are developed so as to be arranged densely and orderly, so that the dot reproducibility is excellent.

  The weight average particle diameter (D4) and particle size distribution of the toner are measured by, for example, a Coulter counter method. Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).

  First, 0.1 mL to 5 mL of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 mL to 150 mL of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing a 1% by mass NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 mg to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute to 3 minutes, and the weight and number of toner particles or toner are measured by the measurement apparatus using a 100 μm aperture as the aperture. Calculate weight distribution and number distribution. From the obtained distribution, the weight average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As a channel, it is 2.00 micrometers or more and less than 2.52 micrometers; 2.52 micrometers or more and less than 3.17 micrometers; 3.17 micrometers or more and less than 4.00 micrometers; 4.00 micrometers or more and less than 5.04 micrometers; 5.04 micrometers or more and less than 6.35 micrometers; .35 μm or more and less than 8.00 μm; 8.00 μm or more and less than 10.08 μm; 10.08 μm or more and less than 12.70 μm; 12.70 μm or more and less than 16.00 μm; 16.00 μm or more and less than 20.20 μm; Less than 40 μm; 25.40 μm or more and less than 32.00 μm; 3 channels of 32.00 μm or more and less than 40.30 μm are used, and particles having a particle size of 2.00 μm or more and less than 40.30 μm are targeted.

  The toner is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a toner material containing at least a prepolymer made of a modified polyester resin, an unmodified polyester, a colorant, and a release agent. Can be produced by crosslinking and / or elongation reaction in the presence of resin fine particles in an aqueous medium.

  Examples of the prepolymer made of the modified polyester resin include a polyester prepolymer (A) having an isocyanate group. Examples of the compound that extends or crosslinks with the prepolymer include amines (B).

  As the polyester prepolymer (A) having an isocyanate group, for example, a polyester having an active hydrogen group and a polycondensate of polyol (1) and polycarboxylic acid (2) was further reacted with polyisocyanate (3). Thing, etc. Examples of the active hydrogen group possessed by the polyester include hydroxyl groups (alcoholic hydroxyl groups and phenolic hydroxyl groups), amino groups, carboxyl groups, mercapto groups, and the like. Among these, alcoholic hydroxyl groups are particularly preferable.

  Examples of the polyol (1) include diol (1-1) and trivalent or higher polyol (1-2). (1-1) alone or (1-1) and a small amount of (1-2) ) Is preferred.

  Examples of the diol (1-1) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether Glycol (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol) A, bisphenol F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the alicyclic diol; Alkylene oxide phenols (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts, and the like. Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferable, and combined use of alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms is particularly preferable.

  Examples of the trivalent or higher polyol (1-2) include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); Phenols (trisphenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or higher polyphenols, and the like.

  Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). Among these, (2-1) alone and (2 A mixture of -1) and a small amount of (2-2) is preferred.

  Examples of the dicarboxylic acid (2-1) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid). , Terephthalic acid, naphthalenedicarboxylic acid, etc.). Among these, alkenylene dicarboxylic acid having 4 to 20 carbon atoms and aromatic dicarboxylic acid having 8 to 20 carbon atoms are particularly preferable.

  Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polycarboxylic acid (2), you may make it react with polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.

  The ratio of the polyol (1) to the polycarboxylic acid (2) is not particularly limited and may be appropriately selected depending on the intended purpose. The equivalent ratio [OH] / hydroxyl group [OH] to carboxyl group [COOH] [COOH] is preferably 2/1 to 1/1, more preferably 1.5 / 1 to 1/1, and still more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; And those blocked with caprolactam, etc. These may be used individually by 1 type and may use 2 or more types together.

  The ratio of the polyisocyanate (3) is preferably 5/1 to 1/1 as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1 is more preferable, and 2.5 / 1 to 1.5 / 1 is still more preferable. If the [NCO] / [OH] exceeds 5, the low-temperature fixability may be deteriorated. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester is lowered, and the resistance Hot offset property deteriorates.

  There is no restriction | limiting in particular in content of the polyisocyanate (3) component in the prepolymer (A) which has an isocyanate group at the said terminal, Although it can select suitably according to the objective, 0.5 mass%-40 % By mass is preferable, 1% by mass to 30% by mass is more preferable, and 2% by mass to 20% by mass is further preferable. When the content is less than 0.5% by mass, the hot offset resistance deteriorates and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. When the content exceeds 40% by mass, low-temperature fixability is obtained. May get worse.

  The isocyanate group contained per molecule in the prepolymer (A) having an isocyanate group is not particularly limited and may be appropriately selected depending on the intended purpose. The number is preferably 3 to 3, more preferably 1.8 to 2.5 on average. When the number is less than 1 per molecule, the molecular weight of the urea-modified polyester is lowered, and the hot offset resistance may be deteriorated.

Examples of the amines (B) include a diamine (B1), a trivalent or higher polyamine (B2), an amino alcohol (B3), an amino mercaptan (B4), an amino acid (B5), and an amino group of B1 to B5. (B6), etc.
Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane), Diamine cyclohexane, isophorone diamine, etc.); aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.), and the like.
Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine.
Examples of the amino alcohol (B3) include ethanolamine and hydroxyethylaniline.
Examples of the amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan.
Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid.
Examples of the blocked B1-B5 amino group (B6) include ketimine compounds and oxazoline compounds obtained from the amines of B1-B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Can be mentioned.
Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of the urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), or those obtained by blocking them (ketimine compounds).

  The ratio of the amines (B) is the equivalent ratio [NCO] / [NHx] of the isocyanate group [NCO] in the prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (B). Is preferably 1/2 to 2/1, more preferably 1.5 / 1 to 1 / 1.5, and still more preferably 1.2 / 1 to 1 / 1.2. When the [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates.

  The polyester (i) modified with the urea bond may contain a urethane bond together with the urea bond. The molar ratio between the urea bond content and the urethane bond content is not particularly limited and can be appropriately selected according to the purpose, but is preferably 100/0 to 10/90, more preferably 80/20 to 20/80. 60/40 to 30/70 is more preferable. When the molar ratio of the urea bond is less than 10%, the hot offset resistance may be deteriorated.

By these reactions, the modified polyester used in the toner, especially the urea-modified polyester (i) can be produced. These urea-modified polyesters (i) are produced by a one-shot method or a prepolymer method.
The weight average molecular weight of the urea-modified polyester (i) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10,000 or more, more preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. Is more preferable. When the weight average molecular weight is less than 10,000, the hot offset resistance may be deteriorated.

  The number average molecular weight of the urea-modified polyester (i) is not particularly limited when the unmodified polyester (ii) described below is used, and can be appropriately selected according to the purpose. However, it may be a number average molecular weight that is easy to obtain. In the case of the urea-modified polyester (i) alone, the number average molecular weight is preferably 20,000 or less, more preferably 1,000 to 10,000, and further preferably 2,000 to 8,000. When the number average molecular weight exceeds 20,000, low temperature fixability and glossiness when used in a full color image forming apparatus may be deteriorated.

  Not only the polyester (i) modified with the urea bond can be used alone, but also the polyester (ii) not modified can be contained as a binder resin component together with this (i). By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color apparatus are improved, so that it is preferable to use alone. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i), and preferred ones are also the same as (i). Further, (ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, for example, may be modified with a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance.

  The polyester component of the urea-modified polyester (i) and the unmodified polyester (ii) preferably have a similar composition. The mass ratio of (i) and (ii) in the case of containing (ii) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5/95 to 80/20. -30/70 is more preferable, 5 / 95-25 / 75 is still more preferable, and 7 / 93-20 / 80 is particularly preferable. When the mass ratio of (i) is less than 5% by mass, the hot offset resistance may be deteriorated, and it may be disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

The peak molecular weight of the unmodified polyester (ii) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1,000 to 30,000, more preferably 1,500 to 10,000. Preferably, 2,000-8,000 are more preferable. When the peak molecular weight is less than 1,000, the heat-resistant storage stability may be deteriorated, and when it exceeds 30,000, the low-temperature fixability may be deteriorated.
The hydroxyl value of the unmodified polyester (ii) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g to 120 mgKOH / g, and 20 mgKOH. / G to 80 mgKOH / g is more preferable. If the hydroxyl value is less than 5 mgKOH / g, it may be disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.
The acid value of the unmodified polyester (ii) is not particularly limited and may be appropriately selected depending on the intended purpose. It is preferably 1 mgKOH / g to 30 mgKOH / g, more preferably 5 mgKOH / g to 20 mgKOH / g. preferable. By having an acid value, it tends to be negatively charged.

  The glass transition temperature (Tg) of the unmodified polyester (ii) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50 ° C to 70 ° C, more preferably 55 ° C to 65 ° C. preferable. When the glass transition temperature is less than 50 ° C., blocking of the toner during high-temperature storage may be deteriorated, and when it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the toner used in the present invention tends to have good heat-resistant storage stability even when the glass transition temperature is low, as compared with known polyester-based toners.

The polyester modified with the urea bond can be produced by the following method.
First, the polyol (1) and the polycarboxylic acid (2) are heated to 150 ° C. to 280 ° C. in the presence of an esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and are generated while reducing the pressure as necessary. Water is distilled off to obtain a polyester having a hydroxyl group. Subsequently, this is made to react with polyisocyanate (3) at 40 to 140 degreeC, and the prepolymer (A) which has an isocyanate group is obtained. Further, (A) is reacted with amines (B) at 0 ° C. to 140 ° C. to obtain a polyester modified with a urea bond. When reacting (3) and reacting (A) and (B), a solvent may be used as necessary.

  There is no restriction | limiting in particular as said solvent, According to the objective, it can select suitably, For example, aromatic solvents (toluene, xylene, etc.); Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); Esters (acetic acid) Ethyl etc.); inactive to isocyanate (3) such as amides (dimethylformamide, dimethylacetamide, etc.), ethers (tetrahydrofuran, etc.).

  In the case where the polyester (ii) not modified with a urea bond is used in combination, a polyester (ii) not modified is produced in the same manner as the polyester having a hydroxyl group, and this is modified with the urea bond. It melt | dissolves in the solution after completion | finish of reaction of polyester (i), and mixes.

The toner can be manufactured by the following method, but is not limited thereto.
The toner may be formed by reacting a dispersion made of a prepolymer (A) having an isocyanate group in an aqueous medium with (B), or using a urea-modified polyester (i) produced in advance. Good. As a method for stably forming a dispersion comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium, a toner raw material comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force.

  The prepolymer (A) and other toner materials (hereinafter sometimes referred to as toner raw materials), colorants, colorant master batches, mold release agents, charge control agents, unmodified polyesters, Mixing may be performed when the dispersion is formed in the medium, but it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner raw materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium. It may be added later. For example, after forming particles not containing a colorant, the colorant can be added by a known dyeing method.

  As the aqueous medium, water alone may be used, but a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like.

  The amount of the aqueous medium used with respect to 100 parts by mass of the toner material containing the urea-modified polyester (i) and the prepolymer (A) is not particularly limited and may be appropriately selected depending on the intended purpose. 1,000 parts by mass is preferable, and 100 parts by mass to 1,000 parts by mass is more preferable. When the amount used is less than 50 parts by mass, the toner material is not well dispersed, and toner particles having a predetermined particle size may not be obtained. When the amount exceeds 2,000 parts by mass, it is not economical.

  Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

The dispersion method is not particularly limited and may be appropriately selected depending on the intended purpose. For example, known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. . Among these. In order to make the particle size of the dispersion 2 μm to 20 μm, a high-speed shearing method is preferable.
When a high-speed shearing disperser is used, the number of rotations is not particularly limited and can be appropriately selected according to the purpose, but is preferably 1,000 rpm to 30,000 rpm, more preferably 5,000 rpm to 20,000 rpm. preferable. The dispersion time is not particularly limited and may be appropriately selected depending on the intended purpose. However, in the case of a batch method, 0.1 to 5 minutes is preferable. There is no restriction | limiting in temperature as dispersion | distribution, Although it can select suitably according to the objective, 0 to 150 degreeC is preferable and 40 to 98 degreeC is more preferable. Higher temperatures are preferred in that the dispersion made of urea-modified polyester (i) or prepolymer (A) has a low viscosity and is easy to disperse.

  In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner material is dispersed in the aqueous medium, or may be dispersed in the aqueous medium. An amine (B) may be added later to cause a reaction from the particle interface. In this case, urea-modified polyester is preferentially produced on the surface of the manufactured toner, and a concentration gradient can be provided inside the particles.

In the reaction, it is preferable to use a dispersant as necessary.
There is no restriction | limiting in particular as said dispersing agent, According to the objective, it can select suitably, For example, surfactant, a slightly water-soluble inorganic compound dispersing agent, a polymeric protective colloid, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, surfactants are preferable.

  Examples of the surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.

  Examples of the anionic surfactant include alkyl benzene sulfonates, α-olefin sulfonates, phosphate esters, and the like. Among these, those 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- [omega-fluoroalkyl (6 carbon atoms). -11) Oxy] -1-alkyl (carbon number 3-4) sodium sulfonate, 3- [omega-fluoroalkanoyl (carbon number 6-8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (Carbon number 11-20) carboxylic acid or its metal salt, perfluoroalkyl carboxylic acid (carbon number 7-13) or its metal salt, perfluoroalkyl (carbon number 4-12) sulfonic acid or its metal salt, perfluoro Octanesulfonic acid diethanolamide, N-propyl-N- (2-hydro Ciethyl) perfluorooctanesulfonamide, perfluoroalkyl (carbon number 6-10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (carbon number 6-10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (carbon number) 6-16) ethyl phosphate, and the like. Examples of commercially available surfactants having a fluoroalkyl group include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.); Fluorard FC-93, FC-95, FC-98, FC -129 (manufactured by Sumitomo 3M Co., Ltd.); Unidyne DS-101, DS-102 (manufactured by Daikin Industries, Ltd.); Megafac F-110, F-120, F-113, F-191, F-812, F- 833 (manufactured by DIC Corporation); Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products); Etc.).

Examples of the cationic surfactant include amine salt type surfactants and quaternary ammonium salt type cationic surfactants. Examples of the amine salt type surfactant include alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazolines, and the like. Examples of the quaternary ammonium salt type cationic surfactant include alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, and the like. It is done. Among the cationic surfactants, aliphatic quaternary ammonium such as aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, and perfluoroalkyl (6 to 10 carbon atoms) sulfonamidopropyltrimethylammonium salt. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like.
Examples of commercially available cationic surfactants include Surflon S-121 (Asahi Glass Co., Ltd.); Florard FC-135 (Sumitomo 3M Co., Ltd.); Unidyne DS-202 (Daikin Industries Co., Ltd.), MegaFuck F-150, F-824 (manufactured by DIC Corporation); Xtop EF-132 (manufactured by Tochem Products);

  Examples of the nonionic surfactant include fatty acid amide derivatives and polyhydric alcohol derivatives.

  Examples of the amphoteric surfactant include alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine, N-alkyl-N, N-dimethylammonium betaine, and the like.

  Examples of the poorly water-soluble inorganic compound dispersant include tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite.

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

  The acids are not particularly limited and may be appropriately selected depending on the purpose. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, Maleic acid, maleic anhydride, etc. are mentioned. 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, glycerol monoacrylate Glycerin monomethacrylate, N-methylolacrylamide, N-methylolmethacrylamide, 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 the esters of vinyl alcohol and a compound containing a carboxyl group include vinyl acetate, vinyl propionate, vinyl butyrate, and the like. Examples of the amide compound or these methylol compounds include acrylamide, methacrylamide, diacetone acrylamide acid, or these methylol compounds. Examples of the chlorides include acrylic acid chloride and methacrylic acid chloride. Examples of the homopolymer or copolymer such as those having a nitrogen atom or a heterocyclic ring thereof include vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, and ethylene imine. Examples of the polyoxyethylene are polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene Examples thereof include oxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, and polyoxyethylene nonyl phenyl ester. Examples of the celluloses include methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and the like.

  In the preparation of the dispersion, a dispersion stabilizer can be used as necessary. Examples of the dispersion stabilizer include acids such as calcium phosphate salts and those that are soluble in alkali.

When the dispersion stabilizer is used, the calcium phosphate salt can be removed from the fine particles by a method of dissolving the calcium phosphate salt with an acid such as hydrochloric acid and then washing with water or a method of decomposing with an enzyme.
In the preparation of the dispersion, a catalyst for the extension reaction or the crosslinking reaction can be used. Examples of the catalyst include dibutyltin laurate and dioctyltin laurate.

  Furthermore, in order to reduce the viscosity of the toner material, a solvent in which the urea-modified polyester (i) or the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile from the viewpoint of easy removal.

  The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. For example, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, Examples include trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone. These may be used individually by 1 type and may use 2 or more types together. Among these, aromatic solvents such as toluene and xylene; halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferable, and aromatic solvents such as toluene and xylene are more preferable.

  There is no restriction | limiting in particular in the usage-amount of the solvent with respect to 100 mass parts of said prepolymers (A), Although it can select suitably according to the objective, 300 mass parts or less are preferable, 100 mass parts or less are more preferable, 25 masses Part to 70 parts by mass is more preferable. When the solvent is used, it is removed by heating under normal pressure or reduced pressure after the elongation and / or crosslinking reaction.

  The elongation and / or crosslinking reaction time is selected depending on the reactivity of the isocyanate group structure of the prepolymer (A) and the amines (B), but is preferably 10 minutes to 40 hours, and 2 hours to 24 hours. More preferred. There is no restriction | limiting in particular in reaction temperature, Although it can select suitably according to the objective, 0 to 150 degreeC is preferable and 40 to 98 degreeC is more preferable. Furthermore, a known catalyst can be used as necessary. Examples of the catalyst include dibutyltin laurate and dioctyltin laurate.

  In order to remove the organic solvent from the obtained emulsified dispersion, a method in which the temperature of the entire system is gradually raised to completely evaporate and remove the organic solvent in the droplets can be employed. It is also possible to spray the emulsified dispersion in a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and also remove the aqueous dispersant by evaporating it. is there. As the dry atmosphere in which the emulsified dispersion is sprayed, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, in particular, various air streams heated to a temperature higher than the boiling point of the highest boiling solvent used are generally used. The desired quality can be sufficiently obtained by short-time processing such as spray dryer, belt dryer, rotary kiln.

  When the particle size distribution at the time of emulsification dispersion is wide and washing and drying processes are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classifying into a desired particle size distribution.

  In the classification operation, the fine particle portion can be removed in the liquid by a cyclone, a decanter, centrifugation, or the like. Although classification operation may be performed after obtaining as powder after drying, it is preferable in terms of efficiency to be performed in a liquid. The unnecessary fine particles or coarse particles obtained can be returned to the kneading step and used for the formation of particles. At that time, unnecessary fine particles or coarse particles may be wet.

  The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

  By mixing the resulting dried toner powder with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or by giving mechanical impact force to the mixed powder By immobilizing and fusing on the surface, it is possible to prevent detachment of the foreign particles from the surface of the resulting composite particle.

  As specific means, (1) a method of applying an impact force to the mixture by blades rotating at high speed, (2) the mixture is injected into a high-speed air stream, accelerated, and particles or composite particles are mixed with an appropriate collision plate. There is a method of making it collide. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) was modified, and the grinding air pressure was lowered, hybridization system (manufactured by Nara Machinery Co., Ltd.), A kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), an automatic mortar, and the like.

-Colorant-
The colorant is not particularly limited and may be appropriately selected depending on the purpose. Pigments and dyes that have been conventionally used as toner colorants can be used, and examples thereof include carbon black, lamp black, and iron. Examples thereof include black, ultramarine blue, nigrosine dye, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa Yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, and rose bengal. These may be used individually by 1 type and may use 2 or more types together.
Further, if necessary, in order to give the toner itself magnetic properties, for example, iron oxides such as ferrite, magnetite and maghemite; metals such as iron, cobalt and nickel, or alloys of these with other metals, etc. The magnetic component may be contained in the toner alone or in combination. In addition, these components can also be used as a colorant component.

  The number average particle diameter of the colorant in the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.5 μm or less, more preferably 0.4 μm or less, and 0.3 μm or less. Further preferred. When the number average particle diameter exceeds 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained. On the other hand, the colorant having a fine particle diameter of less than 0.1 μm is sufficiently smaller than a half wavelength of visible light, and thus is considered not to adversely affect the light reflection and absorption characteristics. Therefore, the colorant particles having a number average particle size of less than 0.1 μm contribute to good color reproducibility and transparency of the OHP sheet having a fixed image. On the other hand, when there are many colorants having a particle size larger than 0.5 μm, the transmission of incident light is hindered or scattered, and the brightness of the projected image of the OHP sheet is reduced. There is a tendency to decrease the color. Further, when a large amount of colorant having a particle size larger than 0.5 μm is present, the colorant is detached from the surface of the toner particles, which may cause various problems such as fogging, drum contamination, and poor cleaning. The colorant having a particle size larger than 0.7 μm is preferably 10% by number or less, more preferably 5% by number or less of the total colorant.

  By mixing the colorant together with a part or all of the binder resin in advance after adding a wetting liquid, the binder resin and the colorant are initially sufficiently adhered, The colorant dispersion in the toner particles in the toner production process is more effectively performed, the dispersed particle diameter of the colorant is reduced, and better transparency can be obtained.

  There is no restriction | limiting in particular as binder resin used for kneading | mixing previously, According to the objective, it can select suitably, Resins illustrated as binder resin for toners can be used as it is.

  As a specific method for kneading the mixture of the binder resin and the colorant together with the wetting liquid, for example, the binder resin, the colorant and the wetting liquid are obtained after mixing with a blender such as a Henschel mixer. The obtained mixture can be kneaded at a temperature lower than the melting temperature of the binder resin with a kneader such as a two-roll or three-roll roll to obtain a sample.

  In addition, as the wetting liquid, a general one can be used in consideration of the solubility of the binder resin and the paintability with the colorant, but organic solvents such as acetone, toluene, butanone, and water are colored. From the viewpoint of dispersibility of the agent. Among these, the use of water is particularly preferable from the viewpoint of environmental considerations and maintaining the dispersion stability of the colorant in the subsequent toner production process.

  According to this manufacturing method, not only the particle diameter of the colorant particles contained in the obtained toner is reduced, but also the uniformity of the dispersion state of the particles is increased, so that the color reproducibility of the projected image by OHP is further improved. Get better.

-Release agent-
The toner preferably contains a release agent.
There is no restriction | limiting in particular as said mold release agent, According to the objective, it can select suitably, For example, polyolefin wax (polyethylene wax, polypropylene wax, etc.); Long chain hydrocarbon (paraffin wax, sasol wax, etc.); And carbonyl group-containing wax. Among these, a carbonyl group-containing wax is particularly preferable.

  Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate etc.); polyalkanoic acid amides (ethylenediamine dibehenyl amide etc.); polyalkylamides (tristearyl trimellitic acid) Amide etc.); dialkyl ketone (distearyl ketone etc.), etc. are mentioned. Among these, polyalkanoic acid esters are particularly preferable.

  The melting point of the release agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 40 ° C to 160 ° C, more preferably 50 ° C to 120 ° C, and still more preferably 60 ° C to 90 ° C. . When the melting point is less than 40 ° C., the heat resistant storage stability may be adversely affected. When the melting point exceeds 160 ° C., cold offset may easily occur during fixing at a low temperature.

  The melt viscosity of the release agent is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 cps to 1,000 cps, more preferably 10 cps to 100 cps at a temperature 20 ° C. higher than the melting point. When the melt viscosity exceeds 1,000 cps, the effect of improving hot offset resistance and low-temperature fixability may be poor.

  The content of the release agent in the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 40% by mass or less, and more preferably 3% by mass to 30% by mass.

-Charge control agent-
Further, in order to accelerate the toner charge amount and its rise, a charge control agent may be contained in the toner as necessary. Since a color change occurs when a colored material is used as the charge control agent, a colorless or nearly white material is preferable.

  The charge control agent is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, Examples include quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, salicylic acid derivative metal salts, and the like.

  As the charge control agent, a commercially available product can be used. Examples of the commercially available product include quaternary ammonium salt Bontron P-51, oxynaphthoic acid metal complex E-82, and salicylic acid metal complex. E-84, E-89 of phenol-based condensate (both manufactured by Orient Chemical Co., Ltd.); TP-302, TP-415 of quaternary ammonium salt molybdenum complex (both manufactured by Hodogaya Chemical 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 (both manufactured by Hoechst); LRA-901, LR-147 which is a boron complex (all manufactured by Nippon Kalit Co., Ltd.), Ki Examples thereof include a polymer compound having a functional group such as nacridon, an azo pigment, a sulfonic acid group, a carboxyl group, and a quaternary ammonium salt. These may be used individually by 1 type and may use 2 or more types together.

  The content of the charge control agent is not particularly limited and may be appropriately selected depending on the intended purpose. It is preferably 0.1 parts by weight to 10 parts by weight, and 0.2 parts by weight with respect to 100 parts by weight of the toner. Part-5 mass parts is more preferable. When the content exceeds 10 parts by mass, the chargeability of the toner is too large, the effect of the charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is decreased, The image density may be lowered. These charge control agents can be dissolved and dispersed after being melt-kneaded together with a masterbatch and a binder resin, or they may be added directly when dissolved and dispersed in an organic solvent. You may fix to.

-Resin fine particles-
The resin fine particles are added mainly for dispersion stabilization when the toner material is dispersed in the aqueous medium during the toner production process.
The resin fine particles are not particularly limited, and any resin can be used as long as it is a resin capable of forming an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. Epoxy resin, polyester resin, polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, polycarbonate resin, and the like. These may be used individually by 1 type and may use 2 or more types together. Among these, a vinyl resin, a polyurethane resin, an epoxy resin, a polyester resin, or a combination thereof is preferable because an aqueous dispersion of fine spherical resin particles can be easily obtained.

  As the vinyl resin, a polymer obtained by homopolymerization or copolymerization of a vinyl monomer is used. For example, a styrene- (meth) acrylic acid ester resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylic acid ester. Examples thereof include a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer.

-External additive-
The external additive is added to assist the fluidity, developability and chargeability of the toner particles. As the external additive, inorganic fine particles are preferable.

  The inorganic fine particles are not particularly limited and can be appropriately selected depending on the purpose. For example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, 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, silicon carbide, silicon nitride, Etc. These may be used individually by 1 type and may use 2 or more types together.

The primary particle diameter of the inorganic fine particles is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 5 nm to 2 μm, and more preferably 5 nm to 500 nm. Further, BET specific surface area of the inorganic fine particles is not particularly limited and may be appropriately selected depending on the intended ^purpose, 20m ² / ^g~500m 2 / g are preferred. The amount of the inorganic fine particles added to the toner is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.01% by mass to 5% by mass, and 0.01% by mass to 2.0% by mass. % Is more preferable.

  Other polymer fine particles, for example, polycondensation systems such as polystyrene, methacrylic acid ester copolymer, acrylic acid ester copolymer, silicone, benzoguanamine, nylon, etc. obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization And polymer particles made of a thermosetting resin.

  In addition, a fluidizing agent may be added to the toner. The fluidizing agent performs surface treatment to increase hydrophobicity, and can prevent deterioration of flow characteristics and charging characteristics even under high humidity. Examples of the fluidizing agent include a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent, silicone oil, a modified silicone oil, Etc.

  Examples of the cleaning improver for removing the developer after transfer remaining on the photoreceptor or intermediate transfer member include metal soaps such as zinc stearate, calcium stearate, stearic acid; polymethyl methacrylate fine particles, polystyrene Examples thereof include polymer fine particles produced by soap-free emulsion polymerization of fine particles and the like. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 μm to 1 μm.

  By using such a toner, a high-quality toner image having excellent development stability can be formed.

  The image forming apparatus of the present invention can be applied not only to the above-described polymerization toner having a configuration suitable for obtaining a high quality image, but also to an irregular shaped toner by a pulverization method. Even in this case, the life of the apparatus can be greatly extended. As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.

  The binder resin used in the pulverized toner is not particularly limited and may be appropriately selected depending on the intended purpose. For example, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, or a substituted product thereof. Homopolymer; Styrene / p-chlorostyrene copolymer, styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / acrylic acid Ethyl 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 / Acryloni Styrene copolymers such as ril copolymer, styrene / vinyl methyl ketone copolymer, styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polyacryl Acrylate ester-based homopolymers such as butyl acid, polymethyl methacrylate, and polybutyl methacrylate, or copolymers thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester-based polymers, polyurethane-based polymers, polyamides Examples thereof include a polymer, a polyimide polymer, a polyol polymer, an epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, and an aromatic petroleum resin. These may be used individually by 1 type and may use 2 or more types together. Among these, a styrene-acrylic copolymer resin, a polyester resin, and a polyol resin are preferable from the viewpoint of electrical characteristics and cost, and a polyester resin and a polyol resin are particularly preferable as those having good fixing characteristics.

  In the pulverized toner, the above-mentioned colorant, mold release agent, charge control agent, etc., together with the binder resin, are premixed as necessary, and then kneaded at a temperature near the melting temperature of the binder resin. After cooling, the toner may be prepared through a pulverization and classification step, and the external additive may be added and mixed as necessary.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the image carrier, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the image carrier. Move to the surface. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the image carrier.
The developer accommodated in the developing device is a developer containing the toner, but the developer may be a one-component developer or a two-component developer.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the image carrier with the visible image using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited, and can be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

  The image carrier is an intermediate transfer member used for image formation by a so-called intermediate transfer method in which a toner image formed on a photosensitive member is primarily transferred to perform color superposition and further transferred to a recording medium. It may be.

-Intermediate transfer member-
As the intermediate transfer member, one showing conductivity having a volume resistivity of 1.0 × 10 ^{5 to} 1.0 × 10 ¹¹ Ω · cm is preferable. When the volume resistivity is less than 1.0 × 10 ⁵ Ω · cm, so-called transfer dust is generated in which the toner image is disturbed due to discharge when the toner image is transferred from the photosensitive member onto the intermediate transfer member. If it exceeds 1.0 × 10 ¹¹ Ω · cm, the counter charge of the toner image remains on the intermediate transfer member after the toner image is transferred from the intermediate transfer member to a recording medium such as paper. It may appear as an afterimage on the image.

Examples of the intermediate transfer member include, for example, a metal oxide such as tin oxide and indium oxide, conductive particles such as carbon black, or a conductive polymer, either alone or in combination, and kneaded with a thermoplastic resin, followed by extrusion molding. A cylindrical shape or a cylindrical shape can be used. In addition, a conductive liquid or a conductive polymer is added to a resin liquid containing a monomer or oligomer capable of thermal crosslinking reaction as necessary, and centrifugal molding is performed while heating to form an endless belt-shaped intermediate transfer body. You can also.
When a surface layer is provided on the intermediate transfer member, the resistance is adjusted by appropriately using a conductive substance in the composition excluding the charge transport material among the surface layer materials used for the surface layer of the photoreceptor. Can be used.

The transfer unit (the primary transfer unit and the secondary transfer unit) preferably includes at least a transfer unit that peels and charges the visible image formed on the image carrier to the recording medium side. . There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

<Protective layer forming step and protective layer forming means>
The protective layer forming step is a step of forming the protective layer by applying the image carrier protective agent of the present invention to the surface of the image carrier after the transfer.
As the protective layer forming means, the protective layer forming apparatus of the present invention described above can be used.

<Other processes and other means>
-Fixing step and fixing means-
The fixing step is a step of fixing the visible image transferred to the recording medium using the fixing unit, and may be performed each time the toner of each color is transferred to the recording medium, or may be applied to the toner of each color. On the other hand, it may be carried out simultaneously at the same time in a state of being laminated.
The fixing unit is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt.
There is no restriction | limiting in particular in the heating in the said heating-pressing means, Although it can select suitably according to the objective, 80 to 200 degreeC is preferable.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

-Cleaning process and cleaning means-
The cleaning step is a step of removing the toner remaining on the image carrier and can be suitably performed by a cleaning unit.
The cleaning unit is preferably provided downstream of the transfer unit and upstream of the protective layer forming unit.
The cleaning means is not particularly limited as long as the toner remaining on the image carrier can be removed, and can be selected as appropriate. For example, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade A cleaner, a brush cleaner, a web cleaner, etc. are mentioned.

-Static elimination process and static elimination means-
The neutralization step is a step of performing neutralization by applying a neutralization bias to the image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the image carrier. For example, a neutralization lamp or the like is preferable. It is done.

-Recycling process and recycling means-
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, According to the objective, it can select suitably, For example, a well-known conveyance means etc. are mentioned.

-Control process and control means-
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

Here, FIG. 2 is a sectional view showing an example of the image forming apparatus 100 having the protective layer forming apparatus of the present invention.
Around the drum-shaped image carriers 1Y, 1M, 1C, and 1K, a protective layer forming device 2, a charging unit 3, an exposure unit 8, a developing unit 5, a transfer unit 6, and a cleaning unit 4 are arranged, respectively. Image formation is performed by operation.

Next, a series of processes for image formation will be described using a negative-positive process.
An image carrier 1 typified by an organic photoreceptor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by a charging means 3.
When the image carrier is charged by the charging unit 3, the image carrier 1Y, 1M, 1C, 1K is suitable for charging the image carrier 1Y, 1M, 1C, 1K to a desired potential from a voltage application mechanism (not shown). A voltage having an appropriate magnitude or a charging voltage obtained by superimposing an AC voltage thereon is applied.
The charged image carriers 1Y, 1M, 1C, and 1K form a latent image with laser light irradiated by the exposure means 8 such as a laser optical system (the absolute value of the exposed portion potential is greater than the absolute value of the non-exposed portion potential). Low potential).
Laser light is emitted from a semiconductor laser, and the surfaces of the image carriers 1Y, 1M, 1C, and 1K are scanned in the direction of the rotation axis of the image carrier by a polygonal polygonal mirror (polygon) that rotates at high speed.
The latent image formed in this way is developed with the toner supplied on the developing sleeve, which is a developer carrying member in the developing means 5, or with the developer composed of toner and carrier, and a toner image is formed. The
At the time of developing the electrostatic latent image, a voltage of an appropriate magnitude is present between the exposed portion and the non-exposed portion of the image carrier 1Y, 1M, 1C, 1K from the voltage application mechanism (not shown) to the developing sleeve. Alternatively, a developing bias in which an AC voltage is superimposed on this is applied.

The toner images formed on the image carriers 1Y, 1M, 1C, and 1K corresponding to the respective colors are transferred onto the intermediate transfer body 60 by the transfer unit 6 and fed from the paper supply unit 200, such as paper. A toner image is transferred onto the recording medium.
At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer unit 6 as a transfer bias. Thereafter, the intermediate transfer member 60 is separated from the image carrier 1 to obtain a transfer image.
In addition, the toner remaining on the image carrier is collected by the cleaning unit 4 in the toner collecting chamber in the cleaning unit 4.

  As the image forming apparatus, a plurality of the developing units are used, and a plurality of toner images of different colors sequentially produced by the plurality of developing units are sequentially transferred onto a recording medium, and then sent to a fixing unit, where Even after a plurality of toner images prepared in the same manner are sequentially transferred onto an intermediate transfer member, and then transferred to a recording medium such as paper, Similarly, a fixing means may be used.

The charging means 3 is preferably a charging means disposed in contact with or close to the surface of the image carrier. As the charging means, a discharge wire is used. As a result, the amount of ozone generated during charging can be greatly suppressed as compared with corona dischargers such as so-called corotrons and scorotrons.
In the charging means for charging in contact with or close to the surface of the image carrier, as described above, the discharge is performed in the region near the surface of the image carrier, so that the electrical stress on the image carrier tends to increase. It is. However, by using the protective layer forming apparatus using the image carrier protecting agent of the present invention, the image carrier can be maintained for a long time without deteriorating, so that stable image quality can be ensured.

<Process cartridge>
The process cartridge used in the present invention comprises at least an image carrier and the protective layer forming means of the present invention, and further, if necessary, charging means, exposure means, developing means, transfer means, cleaning means, It has other means such as static elimination means.
The process cartridge can be detachably mounted on various electrophotographic image forming apparatuses, and is preferably detachably mounted on the image forming apparatus of the present invention.

Here, FIG. 3 is a schematic view showing an example of a process cartridge used in the present invention.
The process cartridge is provided with a protective layer forming device 2 disposed opposite to the photosensitive drum as the image carrier 1, and includes an image carrier protective agent 21, a protective agent supply member 22, a pressing force applying member 23, a protective layer. The forming member 24 is configured.
Further, the image carrier 1 has a surface on which the image carrier protective agent or toner partially deteriorated after the transfer process remains, but the surface residue is cleaned and cleaned by the cleaning unit 4.
In FIG. 3, the cleaning unit 4 is provided upstream of the image carrier protecting agent supply unit, and includes a cleaning member 41 and a cleaning pressing mechanism 42, and is abutted at an angle similar to a so-called counter type (leading type). ing.
An image carrier protective agent 21 is supplied from a protective agent supply member 22 to the surface of the image carrier 1 from which the residual toner on the surface and the deteriorated image carrier protective agent have been removed by the cleaning means 4, thereby forming a protective layer. A film-like protective layer is formed by the member 24. At this time, the image carrier protecting agent 21 of the present invention has a better adsorptivity to the portion of the surface of the image carrier that is highly hydrophilic due to electrical stress. Even if a stress is applied and the surface of the image carrier starts to deteriorate partially, the image carrier itself can be prevented from progressing by adsorption of the protective agent.
The image carrier 1 on which the film-like protective layer is formed in this way is charged by the charging means 3, and then an electrostatic latent image is formed by exposure L such as a laser, and developed by the developing means 5 to be a visible image. And transferred to the recording medium 7 by the transfer means 6 outside the process cartridge.

  According to the image forming apparatus and the process cartridge of the present invention, it is possible to prevent wear and filming of the image carrier, contamination of the charging unit, and toner slippage in the cleaning process, so that an extremely high quality image can be obtained over a long period of time. It can be formed stably.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
The volume average particle diameter of the melamine-formaldehyde resin particles used in the following Examples and Comparative Examples and the average primary particle diameter of the inorganic lubricant were measured as follows.

<Measurement of volume average particle diameter of melamine-formaldehyde resin particles>
The volume average particle size of the melamine-formaldehyde resin particles was measured using a laser scattering / diffraction type particle size measuring device (Microtrack MT3000II, manufactured by Nikkiso Co., Ltd.).

<Measurement of average primary particle size of inorganic lubricant>
The average primary particle size of the inorganic lubricant was determined based on an image observed with a scanning electron microscope (SEM) (thermal F-SEM, manufactured by Zeiss, ULTRA55), image analysis / measurement software (Image-pro plus 4.0j, (Media Cybernetics, Inc.), and the average of 10 was measured.

Example 1
-Production of image carrier protective agent-
70 parts by mass of zinc stearate (made by Wako Pure Chemical Industries, Ltd.) as a fatty acid metal salt, 10 parts by mass of melamine-formaldehyde resin particles 1 (made by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.05 μm) , And a mixture of 20 parts by mass of boron nitride (manufactured by Saint-Gobain, IDL600, average primary particle size 0.6 μm) as an inorganic lubricant, placed in a mold of a predetermined size, pressure 130 kN, compression time 10 seconds Then, after cooling, the solid was removed from the mold, cut into a size of 10 mm × 21 mm × 300 mm, and attached to a metal support with double-sided tape to prepare an image carrier protective agent.

<Image formation>
An image carrier protecting agent was applied to a photoconductor as an image carrier using an apparatus obtained by modifying the image forming apparatus (image MP C4500, manufactured by Ricoh Co., Ltd.) shown in FIG. That is, in the image forming unit of the image forming apparatus (image MP C4500, manufactured by Ricoh Co., Ltd.), a photosensitive member (product equipped with image MP C4500) used in the image forming apparatus was used as an image carrier. The image carrier protecting agent used in the image forming apparatus was replaced with the produced image carrier protecting agent of Example 1. Further, a brush roller as a protective agent supply member used in the image forming apparatus was used as it was. In addition, a toner used in the image forming apparatus (a product equipped with imagio MP C4500) was used as the toner.

  Next, using the image forming apparatus, the cleaning property, the contamination of the charging unit, the protection property (wear and filming) of the photosensitive member, and the scratch of the photosensitive member were evaluated as follows. The results are shown in Tables 1-8.

<Cleanability>
After running 500 sheets (passing paper), replace it with a new image carrier, downstream of the cleaning blade, and at the upper end of the opening of the developing means, a 2 mm thick linear sponge tape (manufactured by Sumitomo 3M Co., Ltd., Scotch tape) 4016), a “through toner catcher” (felt of thickness 1 mm, 8 mm × 310 mm, manufactured by Ashiya Co., Ltd.) was attached. After 100 runs (passing) using a chart with an image area ratio of 5%, the toner slipped downstream of the cleaning blade during the run (passing) of 20 sheets with an image area ratio of 5% is passed through the “slip-through”. The toner was collected by a “toner catcher” and visually evaluated to evaluate the degree of toner slipping (cleaning property) based on the following criteria.
〔Evaluation criteria〕
◎: Toner does not slip through and cleaning performance is good ○: Toner slipping out slightly, but cleaning performance is not a problem △: Toner slipping out, but at a level that can be actually used × : Toner slip occurs frequently and the cleaning performance is poor.

<Contamination of charging means>
Using a test chart (A4 size) with an image area ratio of 5%, 100,000 images were output, the charging means (charging roller) was visually observed, and the contamination of the charging means was evaluated according to the following criteria.
〔Evaluation criteria〕
A: The charging unit is hardly soiled. B: The charging unit is slightly soiled, but there is no effect on the image in a normal temperature environment (23 ° C., 50% RH). Causes abnormal images (images that appear as black streaks on the image) ×: The charging means is very dirty, and abnormal images (images that appear as black streaks on the image) occur from an early stage (about 5,000 sheets) Do

<Protective properties of photoconductor (wear and filming)>
Using a test chart (A4 size) with an image area ratio of 5%, 100,000 images were output, the photoreceptor was visually observed, and the protection of the photoreceptor was evaluated according to the following criteria.
〔Evaluation criteria〕
A: The photoconductor has little wear and filming. O: The photoconductor has a slight filming, but the acceptable level. Δ: The photoconductor has a filming, and an abnormal image (approx. 20,000 sheets) An image that appears as white streaks on the image occurs x: The photoconductor has filming, and an abnormal image (an image that appears as white streaks on the image) occurs early (about 5,000 sheets).

<Scratches on photoconductor>
Using a test chart (A4 size) with an image area ratio of 5%, 100,000 images were output, and the surface of the photoreceptor was observed with a shape measurement laser microscope VK-8700 (manufactured by Keyence Corporation). Surface scratches were evaluated. Here, the scratch on the surface of the photoreceptor means a streak-like scratch generated on the periphery of the surface of the photoreceptor.
〔Evaluation criteria〕
◎: There is almost no scratch on the surface of the photoconductor. ○: The surface of the photoconductor is slightly scratched, but it is an acceptable level. Δ: There is a scratch on the surface of the photoconductor, and an abnormal image (on the image) An image that appears as a white streak) occurs: The photoconductor surface is scratched, and an abnormal image (an image that appears as a white streak on the image) occurs early (about 5,000 sheets).

(Examples 2-12, 14-16 and Comparative Examples 1-9)
-Preparation and evaluation of image carrier protective agent-
In Example 1, carried out in the same manner as in Example 1 except that the fatty acid metal salt, the inorganic lubricant, the melamine-formaldehyde resin particles, the types and amounts of the comparative components were changed as shown in Tables 1 to 8. The image carrier protecting agents of Examples 2 to 12, 14 to 16 and Comparative Examples 1 to 9 were prepared.
Using the image carrier protective agent thus produced, the cleaning property, the charging means contamination, the photoconductor protection (wear and filming), and the photoconductor scratches were evaluated in the same manner as in Example 1. The results are shown in Tables 1-8.

(Example 13)
-Production of image carrier protective agent-
70 parts by mass of zinc stearate (made by Wako Pure Chemical Industries, Ltd.) as a fatty acid metal salt, 10 parts by mass of melamine-formaldehyde resin particles 3 (manufactured by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.3 μm) , And a mixture of 20 parts by mass of boron nitride (manufactured by Saint-Gobain, IDL600, average primary particle size 0.6 μm) as an inorganic lubricant, heated and melted, injected into a mold, cooled and solidified, The solid was removed from the mold, cut to a size of 10 mm × 21 mm × 300 mm, and attached to a metal support with a double-sided tape to prepare an image carrier protective agent.
Using the image carrier protective agent thus produced, the cleaning property, the charging means contamination, the photoconductor protection (wear and filming), and the photoconductor scratches were evaluated in the same manner as in Example 1. The results are shown in Table 4.

The details of the fatty acid metal salt, inorganic lubricant, melamine-formaldehyde resin particles, and comparative components in Tables 1 to 8 are as follows.
<Fatty acid metal salt>
* Zinc stearate (Wako Pure Chemical Industries, Ltd.)
* Calcium stearate (Wako Pure Chemical Industries, Ltd.)
* Zinc laurate (Wako Pure Chemical Industries, Ltd.)

<Inorganic lubricant>
* Boron nitride (made by Saint-Gobain, IDL600, average primary particle size 0.6 μm)
* Mica (Topy Industries, PDM-5B, average primary particle size 6 μm)

<Melamine-formaldehyde resin particles>
* Melamine-formaldehyde resin particles 1 (made by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.05 μm)
* Melamine-formaldehyde resin particle 2 (made by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.1 μm)
* Melamine-formaldehyde resin particles 3 (manufactured by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.3 μm)
* Melamine-formaldehyde resin particles 4 (made by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.4 μm)
* Melamine-formaldehyde resin particles 5 (manufactured by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.5 μm)
* Melamine-formaldehyde resin particles 6 (made by Nippon Shokubai Co., Ltd., developed product, volume average particle diameter Dv: 0.7 μm)

<Comparison ingredients>
* Alumina (manufactured by Denki Kagaku Kogyo Co., Ltd., DAM-03, average particle size 3.7 μm)
* Nylon fine particles (Toray Industries, Inc., SP-500, average particle size 5 μm)

As an aspect of this invention, it is as follows, for example.
<1> An image carrier protecting agent comprising a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles.
<2> The image carrier protective agent according to <1>, wherein the melamine-formaldehyde resin particles have a volume average particle size of 0.5 μm or less.
<3> The image carrier protecting agent according to any one of <1> to <2>, wherein the volume average particle diameter of the melamine-formaldehyde resin particles is 0.1 μm to 0.4 μm.
<4> The image carrier protecting agent according to any one of <1> to <3>, wherein the fatty acid metal salt is at least one selected from zinc stearate, calcium stearate, and zinc laurate.
<5> The image carrier protecting agent according to any one of <1> to <4>, wherein the inorganic lubricant is at least one selected from mica and boron nitride.
<6> The image carrier protective agent according to any one of <1> to <5>, wherein a mixture of a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles is molded by compression molding. .
<7> The image carrier protecting agent according to any one of <1> to <6>,
And an image carrier protecting agent supply member that supplies the image carrier protecting agent to the surface of the image carrier.
<8> The protective layer forming apparatus according to <7>, further including a protective layer forming member that presses an image carrier protective agent supplied to the image carrier to form a protective layer on the surface of the image carrier.
<9> An image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the image carrier, and a developing unit that develops the electrostatic latent image with toner to form a visible image Transfer means for transferring the visible image onto a recording medium; and protective layer forming means for forming a protective layer by applying an image carrier protective agent to the surface of the image carrier after the transfer of the visible image. An image forming apparatus comprising:
An image forming apparatus, wherein the protective layer forming unit is the protective layer forming apparatus according to any one of <7> to <8>.
<10> The apparatus according to <9>, further including a cleaning unit that removes toner remaining on the surface of the image carrier on the downstream side of the transfer unit in the rotation direction of the image carrier and on the upstream side of the protective layer forming unit. An image forming apparatus.

1 Image carrier (photosensitive drum)
DESCRIPTION OF SYMBOLS 2 Protective layer formation apparatus 3 Charging roller 4 Cleaning means 5 Developing means 6 Transfer roller 8 Exposure means 21 Image carrier protective agent 22 Protective agent supply member 23 Pressing force applying member 24 Protective layer forming member 41 Cleaning member 42 Cleaning pressing mechanism 60 Intermediate Transfer body 100 Image forming apparatus 200 Paper feed mechanism L Exposure

Japanese Patent Publication No.51-22380 JP 2006-350240 A JP 2005-171107 A JP 2007-145993 A JP 2009-186610 A JP 2011-197397 A

Claims (10)

  An image carrier protective agent comprising a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles.   The image carrier protective agent according to claim 1, wherein the melamine-formaldehyde resin particles have a volume average particle size of 0.5 µm or less.   The image carrier protective agent according to any one of claims 1 to 2, wherein the melamine-formaldehyde resin particles have a volume average particle size of 0.1 µm to 0.4 µm.   The image carrier protecting agent according to any one of claims 1 to 3, wherein the fatty acid metal salt is at least one selected from zinc stearate, calcium stearate, and zinc laurate.   The image carrier protecting agent according to claim 1, wherein the inorganic lubricant is at least one selected from mica and boron nitride.   The image carrier protective agent according to any one of claims 1 to 5, wherein a mixture of a fatty acid metal salt, an inorganic lubricant, and melamine-formaldehyde resin particles is molded by compression molding. The image carrier protecting agent according to any one of claims 1 to 6,
An image carrier protecting agent supply member for supplying the image carrier protecting agent to the surface of the image carrier;   The protective layer forming apparatus according to claim 7, further comprising a protective layer forming member that presses an image carrier protective agent supplied to the image carrier to form a protective layer on the surface of the image carrier. An image bearing member; an electrostatic latent image forming unit that forms an electrostatic latent image on the image bearing member; a developing unit that develops the electrostatic latent image with toner to form a visible image; Transfer means for transferring a visible image onto a recording medium; and protective layer forming means for forming a protective layer by applying an image carrier protecting agent to the surface of the image carrier after transferring the visible image. An image forming apparatus having
An image forming apparatus, wherein the protective layer forming unit is the protective layer forming apparatus according to claim 7.   The image forming apparatus according to claim 9, further comprising a cleaning unit that removes toner remaining on the surface of the image carrier on the downstream side of the transfer unit in the rotation direction of the image carrier and on the upstream side of the protective layer forming unit.