JP2010066733A - Protective agent for electrophotographic image carrier, layer forming device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protective agent layer forming device for efficiently, continuously supplying to a photoreceptor a powdered lubricating material produced from the block of a lubricating material such as a metallic soap. <P>SOLUTION: The protective layer forming device 24 includes at least: a protective agent block 21 obtained by forming a surface protective agent for an electrophotographic image carrier like the block; a protective agent supplying member 22 supplying a powdered protective agent obtained from the protective agent block to the surface of the image carrier 1; and a pressure force applying member pressing the protective agent block against the protective agent supplying member, to bring the protective agent block into contact with the protective agent supplying member. In the protective layer forming device 24, the protective agent block is a porous body whose porosity is 2 to 15 vol.%, the surface opposite to the surface coming into contact with the pressure force applying member of the protective agent block is fixed to a base material supporting the protective agent block, and an adhesive for fixing the protective agent block to the base material exists in the pores of the surfaces of the protective agent block and the base material fixed to each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a protective agent block formed by forming a surface protective agent for protecting the surface of an electrophotographic image carrier into a block shape, and a protective agent layer comprising a protective agent supplied from the protective agent block. The present invention relates to a protective agent layer forming device formed on a body surface, an image forming method using the same, an image forming device, and a process cartridge.

  In an image forming apparatus using an electrophotographic process, an image is formed by performing a charging process, an exposure process, a development process, and a transfer process on a photoreceptor. The discharge product generated in the charging process and remaining on the surface of the photoreceptor and the residual toner or toner component remaining on the surface of the photoreceptor after the transfer process are removed through a cleaning process.

As a generally used cleaning method, a rubber blade that is inexpensive, has a simple mechanism, and has excellent cleaning properties is used. However, since the rubber blade is pressed against the photoconductor to remove the residue on the photoconductor surface, mechanical stress due to friction between the photoconductor surface and the cleaning blade is large, resulting in wear of the rubber blade and photoconductor surface layer. Reduce the life of rubber blades and organophotoreceptors. In particular, in an organic photoreceptor, the surface layer of the photoreceptor is heavily worn. In addition, the toner used for image formation in response to the demand for higher image quality has become a small particle size. In an image forming apparatus using small-diameter toner, the rate at which residual toner passes through the cleaning blade increases. In particular, the dimensional accuracy and assembly accuracy of the cleaning blade are not sufficient, and the cleaning blade partially vibrates. In this case, the toner slips through and prevents high-quality image formation. To avoid this, the wear of the cleaning blade is increased by increasing the pressing force of the cleaning blade.
Therefore, in order to extend the life of the organic photoreceptor and maintain high image quality over a long period of time, it is necessary to reduce deterioration of the member due to friction and improve cleaning properties.

In response to this requirement, for example, as shown in Patent Document 1 (Japanese Patent Publication No. 51-22380), a brush or the like is pressed against a metal soap block such as zinc stearate to be pulverized and supplied to the photoconductor, and a lubricant is applied with a cleaning blade. The method of forming the film is used.
By using a metal soap such as zinc stearate, the lubricity of the surface of the photoreceptor is improved, the friction between the photoreceptor and the cleaning blade can be reduced, and the cleaning performance of the residual toner is also improved. Therefore, it was very preferable.

  In recent years, in the charging process, so-called AC charging using a charging roller or the like for charging by superimposing an AC voltage on a DC voltage has been used. This AC charging has excellent performance such as high uniformity of the charging potential of the photoconductor, less generation of oxidizing gas such as ozone and NOx, and miniaturization of the apparatus, but the applied AC voltage. Depending on the frequency, positive and negative discharges of several hundred to several thousand times per second are repeated between the charging member and the photoconductor, and the photoconductor is subjected to this large number of discharges to accelerate the deterioration of the surface layer. For this deterioration, if a lubricant is applied to the photoconductor, the AC charging energy is first absorbed by the lubricant and the photoconductor is difficult to reach, so that the photoconductor is protected.

  The metal soap is decomposed by the AC charging energy, but the metal soap is not completely decomposed and disappears, but a fatty acid having a low molecular weight is generated, and the frictional force between the photosensitive member and the cleaning blade is increased. In addition to the fatty acid, the toner component easily adheres in a film form on the photosensitivity, and the resolution of the image tends to be lowered. . For this reason, it is necessary to supply a large amount of metal soap onto the photoconductor so that the surface of the photoconductor can be immediately covered with metal soap even if fatty acids are generated.

  Furthermore, due to the demand for higher speed image formation, the linear velocity of the photoconductor increases, and accordingly, the amount of metal soap supplied to the photoconductor needs to be increased.

  A metal soap block used in an image forming apparatus is generally produced by putting a melted metal soap into a mold and cooling (for example, Patent Document 2: Japanese Patent Laid-Open No. 10-279998). Since the metal soap block produced in this way is dense, in order to increase the supply amount of metal soap in an image forming apparatus using AC charging and having a high linear velocity of the photoreceptor, a brush pressed against the metal soap block is used. Since the pressure increased, the durability of the brush was not sufficient.

  If the supply amount of the metal soap is too large, a large number of metal soap fine particles are generated. When the metal soap passes through the blade and reaches the charging roller, the metal soap fine particles are electrostatically attached to the charging roller, and the AC The charged metal soap is oxidized and melted by the energy of charging, and is fixed to the charging roller. When the metal soap is fixed, the toner component on the photosensitive member is fixed so as to cover the toner, so that the resistance of the charging roller at that portion becomes high, charging failure occurs, and crossing occurs. was there.

  An image forming apparatus using a metal soap block mixed with lubricating fine particles such as boron nitride is disclosed in Japanese Patent Application Laid-Open No. 2006-350240. When image formation is performed while supplying metal soap and lubricating part particles to the photoreceptor, high-quality image formation can be performed while protecting the photoreceptor.

  However, as in the past, when metal soap is melted and lubricating fine particles are mixed, the molten mixture is placed in a mold, and cooled to make a metal soap block, the metal soap block becomes hard and the brush is pressed. However, there is a problem that the amount of supply to the photosensitive member is difficult to be scraped off. Therefore, if the pressure for pressing the brush is further increased, frictional heat is generated between the brush and the metal soap block, and a small amount of toner adhering to the brush melts and adheres to the metal soap block. There was a problem that metal soap could not be supplied.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2006-350240) discloses a method in which metal soap and boron nitride powder is pressed and molded into a block. Since the metal soap block thus produced is porous and brittle, it is preferable because the metal soap can be supplied to the photoreceptor even if the force of pressing the brush is weakened.

  However, the metal soap block is generally used by being fixed to the base material with an adhesive, and fixed with a pressure-sensitive adhesive with good productivity. However, if the metal soap block is porous, the metal soap block is fixed. Insufficient, and in the process of pressing the brush, the metal soap block moved from the base material or peeled off.

Japanese Patent Laid-Open No. 51-22380 Japanese Patent Laid-Open No. 10-279998 JP 2006-350240 (closest known document) JP 52-36016 A

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention relates to a protective agent layer forming apparatus capable of continuously supplying a powdery lubricating material produced from a block of a lubricating material such as a metal soap to a photoreceptor and an image forming apparatus using the same. And providing a process cartridge.

The present invention is solved by the following (1) to (8).
(1) At least a protective agent block formed by molding a surface protective agent for an electrophotographic image carrier into a block shape, and a powdery protective agent separated from the protective agent block are supplied to the surface of the image carrier. In the protective layer forming apparatus having a protective agent supply member and a pressing force applying member that presses and contacts the protective agent block against the protective agent supply member, the protective agent block has a porosity of 2 to 15% by volume. The surface of the porous body opposite to the surface in contact with the pressing force applying member is fixed to a base material that supports the protective agent block, and the surface of the surface on which the protective agent block is fixed to the base material A protective agent layer forming apparatus, wherein an adhesive for fixing the protective agent block to the substrate is present in the pores.
(2) The said adhesive agent was apply | coated to the said protective agent block and a base material in the viscosity state of 1000-50000 cP, and the said protective agent block and the said base material were adhere | attached, Said 1st term | claim characterized by the above-mentioned. Protective agent layer forming apparatus.
(3) The protective agent layer forming apparatus as described in (1) or (2) above, wherein the protective agent block is mainly composed of metal soap.
(4) The protective agent layer forming apparatus according to any one of (1) to (3), wherein the protective agent block further contains a powder of inorganic material particles. .
(5) The protective agent layer forming apparatus as described in (4) above, wherein the powder of the inorganic material particles contains talc and boron nitride.
(6) A process cartridge using the protective agent layer forming apparatus according to any one of (1) to (5).
(7) An image forming apparatus using the protective agent layer forming apparatus according to any one of (1) to (5).
(8) An image forming apparatus using the process cartridge according to item (6).

  Hereinafter, as is clear from the detailed and specific description, according to the present invention, the presence of the porosity in the protective agent block for the image carrier enables the smooth supply of the protective agent for the image carrier, and the adhesion. Since the agent penetrates and exists in the pores of the protective block for the image carrier and the protective block for the image carrier is fixed to the substrate supporting the protective agent block, the protective block for the image carrier is moved or damaged. The protective layer forming apparatus capable of forming a high-quality image can be provided, and the adhesive has an appropriate viscosity, so that it easily penetrates into the pores of the protective agent block for the image carrier. Therefore, it is possible to provide a protective layer forming apparatus capable of forming a high-quality image without moving or breaking the protective agent block for the image carrier, and even when using a metal soap having a high protective effect, Metal soap material It is possible to provide a protective layer forming apparatus capable of forming a high-quality image without moving or damaging the protective agent block for the image carrier, and further, no streak-like abnormal image is generated. This provides an extremely excellent effect that a protective layer forming apparatus can be provided. In addition, the present invention can provide a process cartridge capable of forming a high-quality image, and can provide an image forming apparatus capable of forming a high-quality image.

  FIG. 4 is a schematic view of the periphery of the image carrier protective agent block when the image carrier protective agent block of the present invention is used. The protective agent block for the image carrier shown in FIG. 4 is a porous body, but the adhesive penetrates into the pores on the surface opposite to the surface in contact with the protective agent supply member (adhesion surface with the substrate). And hardened. The depth of penetration of the adhesive is usually 10 to 300 μm. The larger the porosity, the deeper the penetration, and the fixing of the base material and the protective agent block for the image carrier becomes complete.

  The viscosity of the adhesive when applied to the protective block for image carrier and the substrate of the present invention is 1000 to 60000 cP, preferably 2000 to 50000 cP, and more preferably 300 to 40000 cP. If the viscosity of the adhesive is less than 1000 cP, it will be easy to penetrate into the pores of the protective block for the image carrier, but it will easily move from the adhesive surface until the adhesive is cured, and the adhesive strength will tend to be reduced. This is not preferable because the agent may be sunk to contaminate the surface of the protective agent block for the image carrier. If the viscosity of the adhesive is larger than 60000 cP, it is difficult for the adhesive to penetrate into the pores of the protective agent block for the image carrier, and the adhesive strength tends to decrease, which is not preferable.

  Examples of the adhesive that bonds the protective block for the image bearing member of the present invention and the base material include epoxy-based, acrylate-based, urethane-based, rubber-based adhesive, and pressure-sensitive adhesive. An adhesive is most preferred because of its high adhesive strength.

  In fixing the image bearing member protective agent block of the present invention, the adhesive is applied to the back surface of the image bearing member protective agent block (the surface to be bonded to the substrate), and if necessary, the adhesive is also applied to the base material for bonding. It is preferable to cure the image bearing member with the protective agent block on the lower side and the substrate on the upper side. By doing so, the adhesive penetrates into the pores of the image carrier protective agent block, and the fixing of the base material to the image carrier protective agent block becomes complete.

  The porosity of the entire image carrier protective agent block of the present invention is 2 to 15% by volume, preferably 3 to 12% by volume, and more preferably 4 to 10% by volume. When the porosity of the protective agent block for the image carrier of the present invention is 2% by volume or less, the protective agent block for the image carrier is pressed against the protective agent supply member in order to supply the protective agent for the image carrier to the image carrier. The pressing force to be brought into contact must be increased, the metal soap is likely to adhere to the charging roller, charging failure occurs, black streaks are likely to occur, and the toner on the image carrier protective agent block The protective agent for the image bearing member cannot be supplied to the image bearing member, and it is not preferable. When the porosity of the image carrier protective agent block of the present invention is 15% by volume or more, the elephant carrier protective agent block becomes very brittle, and the image carrier protective agent block is cracked or chipped by a slight impact. It is easy and not preferable.

As a method for providing pores in the protective agent block for the image carrier of the present invention, a method of compressing the protective agent powder and molding it into a block shape, a foaming agent in the protective agent (for example, urethane foam or foamed polystyrene molding). R-21 (Bp = + 8.9 ° C. CHCl ₂ F), R-11 (Bp = + 23.7 ° C. C1 ₃ F), R-113 (Bp = + 47.6 ° C. CCl ₂ F-CCl ₂ ), R— 12 (Bp = −30.0 ° C. CF ₂ Cl ₂ ), Bp = + 39.8 ° C. CH ₂ Cl _2, etc.), a method of forming and defoaming, electrolyte inorganic salts dissolved in solvents such as electrolyte salts, etc. A method of eluting the electrolyte salt with a solvent after melting or molding and cooling the protective agent mixed with the powder can be considered, but in consideration of environmental problems, productivity, and reproducibility, the protective agent powder is compressed and molded The method is most preferable.

  When the protective agent powder is compression molded, the porosity can be adjusted by the particle size of the protective agent powder and the pressure for compressing the protective agent powder. After the protective agent powder is put into the mold, the thickness of the protective agent block for the image bearing member is calculated based on the weight and density of the introduced protective agent, and the compression stops when the pressure is reached. If the mechanism to perform is provided in a press machine, it can adjust to the calculated | required porosity, even if what kind of protective agent powder is used, and is preferable.

  The particle size of the protective agent powder used when compressing and molding the protective agent block for the image carrier is 0.1 to 2000 μm, preferably 1 to 1000 μm, and more preferably 2 to 500 μm. When the particle size of the protective agent powder is smaller than 0.1 μm, the bulk density of the protective agent powder becomes large. Therefore, when the protective agent powder is put into the mold, workability is remarkably lowered, and when compressing, Since the protective agent powder that is washed away from the molding die is left, it is difficult to produce a protective agent having a desired porosity. When the particle size of the protective agent powder is larger than 2000 μm, only a small porosity of the protective agent block for the image carrier can be produced. It is not preferable because it is often greatly different.

  As the protective agent used in the protective agent block for the image bearing member of the present invention, saturated hydrocarbon wax and metal soap are used, but the main component of the metal soap is the film-forming property of the protective agent on the photoreceptor. It is preferable because a protective agent having a high protective effect can be supplied.

[Saturated hydrocarbon wax]
The saturated hydrocarbon wax is not particularly limited and may be appropriately selected according to the purpose. However, the saturated hydrocarbon wax has a sharp peak of heat of fusion in the range of 80 to 130 ° C. and has a low melt viscosity after melting. Is preferred.

According to the protective agent for an image carrier having the structure of the present invention, even if a hard wax component having a high melting point is used, it is possible to supply a necessary and sufficient amount of the protective agent to the surface of the image carrier. Is higher than 130 ° C., the wax component is stretched on the surface of the image bearing member to form a film, and when the protective layer is formed, the spreadability may not be sufficient. An operation such as strong rubbing may be required. In this case, since the mechanical stress on the image carrier tends to be large, it is possible to adjust a homogeneous protective layer for protecting the image carrier from electrical stress while suppressing mechanical deterioration. The adjustment range of the protective layer forming condition is narrowed.
When the melting point is lower than 80 ° C., the protective agent for the image carrier is softened and deformed in the image forming apparatus and may not be supplied onto the image carrier with sufficient supply accuracy. It may be difficult to form a layer.
Examples of general waxes include aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic saturated hydrocarbons, hydrocarbons classified as alicyclic unsaturated hydrocarbons and aromatic hydrocarbons, carnauba wax, Examples include plant natural waxes such as rice bran wax and candelilla wax, and animal natural waxes such as beeswax and snow wax.
In particular, aliphatic saturated hydrocarbons and alicyclic saturated hydrocarbons consisting only of saturated bonds with low reactivity and low reactivity are preferable, and hydrocarbon waxes such as normal paraffin, isoparaffin and cycloparaffin are particularly preferred for addition reaction. It is preferably used in terms of stability over time because it is chemically stable and hardly undergoes an oxidation reaction in actual air.

  Further, by using a hydrocarbon wax containing at least one of Fischer-Tropsch wax and polyethylene wax as a relatively hard wax, the durability of the protective layer itself can be increased, so that it is formed on the surface of the image carrier. Since the protection of the image carrier can be realized without making the thickness of the protective layer excessive, it is more preferable.

Further, since the protective agent layer formed on the surface of the image carrier as described above is exposed to electrical stress and deteriorates, if the molecular weight of the wax is too small, a sufficient protective effect may not be exhibited.
On the other hand, if the molecular weight of the wax is too large, an even protective film may not be formed because a large shear force is required when forming the protective agent component for the image carrier on the image carrier.

  By making the molecular weight of the wax in the range of 350 to 850 on the basis of the weight average molecular weight Mw, the protective effect can be surely expressed, and it is more preferably 400 to 800.

[Metal soap]
Examples of metal soaps include long-chain alkyl carboxylates such as laurate, myristic acid, palmitate, stearate, behenate, lignocerate, serotinate, montanate, melinate, etc. This has an anion (anion) at the end of the hydrophobic part, and this is combined with alkali metal ions such as sodium and potassium, alkaline earth metal ions such as magnesium and calcium, and metal ions such as aluminum and zinc. Compounds.
Specific examples include zinc stearate, calcium stearate, magnesium stearate, zinc laurate, calcium laurate, magnesium laurate, and zinc palmitate. These metal soaps may be used in combination. Among these, zinc stearate having good film forming property and high protective effect is preferable, and a mixture of zinc stearate and palmitic acid is preferable as a main component from the economical aspect.

  The protective agent for an image carrier of the present invention is preferably mixed with a lubricating inorganic powder such as talc or boron nitride as a constituent material. When metallic inorganic soap is mixed with a lubricating inorganic powder such as talc or boron nitride, uneven resistance of the charging roller over time is less likely to occur as described above, so streak-like abnormal images are less likely to occur. It is preferable.

  The content of the lubricating inorganic powder in the entire protective agent for the image carrier is 1 to 15% by weight, preferably 2 to 12% by weight, and more preferably 3 to 10% by weight. If the content of the lubricating inorganic powder in the entire image bearing member protective agent is less than 1% by weight, the effect of preventing unevenness of the resistance of the charging roller over time is low, which is not preferable. If the content of talc and / or boron nitride (lubricating inorganic powder) in the entire image carrier protective agent is greater than 15% by weight, the lubricating inorganic powder accumulates on the photoconductor, and the sensitivity of the photoconductor. Is not preferable.

  Further, the protective agent for an image carrier of the present invention includes inorganic fine particles such as silica, alumina, ceria, zirconia, clay, talc, calcium carbonate, surface hydrophobized fine particles, polymethyl methacrylate fine particles, polystyrene fine particles, Organic fine particles such as silicone resin fine particles and α-olefin-norbornene copolymer resin fine particles can also be mixed. These particles themselves do not have an effect of protecting the image carrier, but have an effect of leveling the protective agent for the image carrier that has adhered too much on the image carrier. Among these, alumina is preferable because it does not lower the sensitivity of the photoreceptor even if it adheres to the photoreceptor. When alumina is used, the particle size is 0.05 to 2 μm, preferably 0.10 to 1 μm, and more preferably 0.15 to 0.7 μm.

  In addition, an amphiphilic organic compound such as a surfactant is used in combination as an additive to increase the affinity between the protective agent for the image carrier and the surface of the image carrier and to assist in the formation of the protective agent layer. May be.

  Since the amphiphilic organic compound may greatly change the surface characteristics of the main material, the addition amount thereof is about 0.01 to 3% by weight with respect to the total weight of the protective agent for the image carrier. It is preferably about 0.05 to 2% by weight.

[Protective layer forming device]
The protective layer forming apparatus of the present invention includes an image carrier, a protective agent supply member that supplies the image carrier protective agent to the surface of the image carrier, and abuts the protective agent supply member by pressing the protective agent for the image carrier. It has at least a pressing force applying member to be made, and further has other means as required.

  The protective layer forming means includes: a pressing force applying member that presses the image carrier protective agent to contact the protective agent supply member; and a protective agent supply member that supplies the image carrier protective agent to the surface of the image carrier. And a protective layer forming member that forms a protective layer by thinning the supplied protective agent for the image carrier, and further has other configurations as necessary.

  In addition, when the protective layer forming apparatus includes the protective layer forming member, the protective layer forming member may also serve as a cleaning member. It is preferable to remove the residue mainly composed of toner on the carrier 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 in a state of being mounted on the image forming apparatus of the present invention. The image forming apparatus includes a photosensitive drum (1) as an image carrier, a charging roller (3) as an example of a charging unit, a cleaning unit (mechanism) (4), an exposure unit (not shown), and a developing unit. And a transfer means.

  The protective layer forming device (2) disposed facing the photosensitive drum (1) as an image carrier is an image carrier protective agent (21), a protective agent supply member (22), a pressing member according to the present invention. It is mainly comprised from a pressure provision member (23), a protective layer formation member (24), etc.

  The protective agent (21) for an image carrier of the present invention is in contact with, for example, a brush-like protective agent supply member (22) by a pressing force from a 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 protective agent for the image carrier held on the surface of the protective agent supply member is transferred to the surface of the image carrier. To supply.

  The protective agent for the image carrier supplied to the surface of the image carrier may not be a sufficient protective layer at the time of supply depending on the selection of the substance type. Therefore, in order to form a more uniform protective layer, for example, The protective layer forming member (24) having a member is thinned to form a protective layer.

  The image bearing member on which the protective layer is formed has, for example, a small gap by contacting or approaching a charging roller (3) to which a DC voltage or a voltage obtained by superimposing an AC voltage is applied by a high voltage power source (not shown). The image carrier is charged by the discharge at. At this time, a part of the protective layer is decomposed or oxidized due to electrical stress, and air discharge products adhere to the surface of the protective layer, resulting in a deteriorated product.

  The deteriorated protective agent for the image carrier is removed by the cleaning mechanism together with the components such as the toner remaining on the image carrier by an ordinary cleaning mechanism. Such a cleaning mechanism may be used also as the above-described protective layer forming member. 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 an appropriate member rubbing state. Since the functions may be different, the functions are separated, and as shown in FIG. 1, a cleaning mechanism (4) including a cleaning member (41), a cleaning pressing mechanism (42), and the like upstream of the image carrier protective agent supply unit. Is preferably provided.

  The blade material used for the protective layer forming member (24) is not particularly limited and may be appropriately selected from known materials for cleaning blades according to the purpose. For example, urethane rubber, hydrin rubber, silicone Examples thereof include rubber and fluororubber. These may be used individually by 1 type and may use 2 or more types together. In these blades, the contact portion with the image carrier may be coated or impregnated with a low coefficient of friction 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 cleaning blade (41) 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. The thickness of the blade is not uniquely defined in consideration of the force applied by pressing, but is preferably 0.5 to 5 mm, and more preferably 1 to 3 mm.
Also, the length of the cleaning blade that protrudes from the support and can bend, that is, the so-called free length, is not unambiguously defined by the balance with the force applied by pressing, but preferably 1 to 15 mm. 2-10 mm is more preferable.

  Other configurations of the protective layer forming blade member (24) include a coating layer of resin, rubber, elastomer, etc. on the surface of an elastic metal blade such as a spring plate via a coupling agent, a primer component or the like as necessary. May be formed by a method such as coating or dipping, and if necessary, thermosetting may be performed, and if necessary, surface polishing or the like may be performed.

  The coating layer contains at least a binder resin and a filler, and further contains other components as necessary.

  There is no restriction | limiting in particular as said binder resin, Although it can select suitably according to the objective, For example, Fluororesin, such as PFA, PTFE, FEP, PVdF; Silicone-type elastomers, such as fluorine-type rubber and methylphenyl silicone elastomer, etc. Can be mentioned.

  The thickness of the elastic metal blade is preferably 0.05 to 3 mm, more preferably 0.1 to 1 mm. In the elastic metal blade, in order to suppress twisting of the blade, a process such as bending may be performed in a direction substantially parallel to the support shaft after the attachment.

  The force that presses the image carrier with the protective layer forming member (24) is sufficient with the force that the powdery protective agent for the image carrier supplied from the protective agent block (21) extends to form a protective agent layer. Yes, the linear pressure is preferably 5 to 80 gf / cm, more preferably 10 to 60 gf / cm.

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. The material of the flexible brush fiber is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyolefin resin (for example, polyethylene, polypropylene); 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); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene- Butadiene resin; fluororesin (eg, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); polyester; nylon; acrylic; rayon; Emissions; polycarbonate; phenolic resins; amino resins (e.g. urea - formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin).
In order to adjust the degree of bending, for example, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. may be combined. .

As a support for the protective agent supply member (22), there are a fixed type and a rotatable roll type. 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 to 500 μm, the length of the brush fiber is 1 to 15 mm, and the brush density is 10,000 to 300,000 per square inch (1.5 × 10 ^{7 to} 4.5 per square meter). × 10 ⁸ pieces) is preferred.

  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 several fibers to hundreds of fine fibers are used as one fiber. It is preferable to prepare from. 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 preferred.

  Moreover, you may provide a coating layer in the brush surface for the purpose of stabilizing the surface shape, environmental stability, etc. of a brush as needed. As a 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. For example, polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc. 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 chloride-acetic acid Vinyl copolymer; silicone resin composed of organosiloxane bond or modified product thereof (eg, modified product by alkyd resin, polyester resin, epoxy resin, polyurethane resin, etc.); Fluorine resins such as fluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene and polychlorotrifluoroethylene; polyamides; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins; epoxy resins or composite resins thereof It is done.

[Image Forming Method and Image Forming Apparatus]
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, a protective layer forming step, and a fixing step, preferably including a cleaning step, and further appropriately as necessary. It includes other selected processes such as a static elimination process, a recycling process, and a control process.

  The image forming apparatus of the present invention comprises at least an image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, a protective layer forming unit, and a fixing unit, preferably a cleaning unit, Other means appropriately selected as necessary, for example, static elimination means, recycling means, control means, and the like are provided.

  The image forming method of the present invention can be suitably carried out by the image forming apparatus of the present invention, the electrostatic latent image forming step can be performed by the electrostatic latent image forming means, and the developing step is the developing 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 fixing step can be performed by the fixing unit. The other steps can be performed by the other means.

<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.

[Image carrier]
The image carrier (sometimes referred to as “electrostatic latent image carrier” or “photoreceptor”) is not particularly limited in material, shape, structure, size, etc., and is appropriately selected from known ones. However, the shape is preferably a drum shape, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine.

  The image carrier (photoreceptor) used in the image forming apparatus of the present invention has a conductive support and at least a photosensitive layer on the conductive support, and further has other layers as necessary. It becomes.

  As the photosensitive layer, a single layer type in which a charge generation material and a charge transport material are mixed, a forward layer type in which a charge transport layer is provided on the charge generation layer, or a charge generation layer is provided on the charge transport layer. There is a reverse layer type. In order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor, an outermost surface layer can be provided on the photosensitive layer. An undercoat layer may be provided between the photosensitive layer and the conductive support. Moreover, an appropriate amount of a plasticizer, an antioxidant, a leveling agent or the like can be added to each layer as necessary.

The conductive support is not particularly limited as long as it has a volume resistance of 1.0 × 10 ¹⁰ Ω · cm or less, and can be appropriately selected according to the purpose. For example, aluminum, Nickel, chromium, nichrome, copper, gold, silver, platinum, etc., metal oxides such as tin oxide, indium oxide, etc., film or cylindrical plastic, paper coated or aluminum by vapor deposition or sputtering It is possible to use a plate made of aluminum alloy, nickel, stainless steel or the like, and a tube subjected to surface treatment such as cutting, superfinishing, polishing, etc. after forming them into a drum shape by extruding and drawing them.

The drum-shaped support preferably has a diameter of 20 to 150 mm, more preferably 24 to 100 mm, and even more preferably 28 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, and more preferably 60 mm or less.
An endless nickel belt or an endless stainless belt as disclosed in Patent Document 4 (Japanese Patent Laid-Open No. 52-36016) can also be used as the conductive support.

  The undercoat layer of the photoreceptor may be composed of a single layer or a plurality of layers. For example, (1) a resin-based component, (2) a white pigment and a resin-based component, 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, titanium oxide is particularly preferable because it is excellent in preventing injection of charges from the conductive support.

  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 thickness of the said undercoat layer, According to the objective, it can select suitably, 0.1-10 micrometers is preferable and 1-5 micrometers is more preferable.

  Examples of the charge generation material in the photosensitive layer include monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments and other azo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, Cyanine dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, etc. Organic pigments or dyes; inorganic materials such as selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, amorphous silicon and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the charge transport material in the photosensitive layer include anthracene derivatives, pyrene derivatives, carbazole derivatives, tetrazole derivatives, metallocene derivatives, phenothiazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styryl hydrazone compounds, enamine compounds, butadiene compounds, distyryl. Examples thereof include compounds, oxazole compounds, oxadiazole compounds, thiazole compounds, imidazole compounds, triphenylamine derivatives, phenylenediamine derivatives, aminostilbene derivatives, and triphenylmethane derivatives. These may be used individually by 1 type and may use 2 or more types together.

  As the binder resin used to form the photosensitive layer, it is electrically insulating, and it is possible to use a known thermoplastic resin, thermosetting resin, photocurable resin, photoconductive resin, or the like. it can. Examples of the binder resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, ethylene-vinyl acetate copolymer, polyvinyl butyral, Polyvinyl acetal, polyester, phenoxy resin, (meth) acrylic resin, polystyrene, polycarbonate, polyarylate, polysulfone, polyethersulfone, ABS resin and other thermoplastic resins, phenol resin, epoxy resin, urethane resin, melamine resin, isocyanate Examples thereof include thermosetting resins such as resins, alkyd resins, silicone resins, thermosetting acrylic resins, polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the antioxidant include phenolic compounds, paraphenylenediamines, organic sulfur compounds, and organic phosphorus compounds.

  Examples of the phenol compound include 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3, 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4-ethyl- 6-t-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3 Tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxy Benzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3 ′) -T-butylphenyl) butyric acid] cricol ester, tocopherols and the like.

  Examples of the paraphenylenediamines include N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl- Examples thereof include p-phenylenediamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

  Examples of the hydroquinones include 2,5-di-t-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl. Examples include hydroquinone and 2- (2-octadecenyl) -5-methylhydroquinone.

  Examples of the organic sulfur compounds include dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like. .

  Examples of the organic phosphorus compounds include triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

  These compounds are known as antioxidants for rubbers, plastics, oils and the like, and commercially available products can be easily obtained.

  The addition amount of the antioxidant is preferably 0.01 to 10% by mass with respect to the total mass of the layer to be added.

  As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is about 0 to 30 parts by mass with respect to 100 parts by mass of the binder resin. Is appropriate.

  Further, a leveling agent may be added to the photosensitive layer. Examples of the leveling agent include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil; polymers having a perfluoroalkyl group in the chain measurement, or oligomers. As for the usage-amount of the said leveling agent, 0-1 mass part is preferable with respect to 100 mass parts of said binder resins.

  The outermost surface layer of the photoreceptor is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning properties, and the like of the photoreceptor. As the outermost surface layer, a polymer having a mechanical strength higher than that of the photosensitive layer and a material in which an inorganic filler is dispersed in the polymer are suitable. The resin used for the outermost surface layer may be either a thermoplastic resin or a thermosetting resin, but the thermosetting resin has high mechanical strength and suppresses abrasion due to friction with the cleaning blade. This is particularly preferable because of its extremely high capacity. 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 without the charge transport capability is formed thick, the sensitivity of the photoreceptor decreases, the potential increases after exposure, and the residual layer Since the potential rise is likely to occur, it is preferable to include the above-described charge transport material in the surface layer or to use a polymer having charge transport ability as the polymer used in the surface layer.

  Since the mechanical strength of the photosensitive layer and the outermost surface layer is generally greatly different, the outermost surface layer is worn by friction with the cleaning blade, and the photosensitive layer is worn away as soon as it disappears. When providing, it is important that the outermost surface layer has a sufficient thickness, preferably 0.1 to 12 μm, more preferably 1 to 10 μm, and further preferably 2 to 8 μm. When the 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. In the case of using a polymer having a charge transport ability, the cost of the polymer having a charge transport ability may be increased.

  The resin used for the outermost surface layer is preferably one that is transparent to writing light at the time of image formation and excellent in insulation, mechanical strength, and adhesion. 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 , Polymethylbenten, 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 using a functional resin, the mechanical strength of the outermost surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

  The outermost surface layer preferably has a charge transporting capability. In order to provide the outermost surface layer with a charge transporting capability, the polymer used for the outermost surface layer and the above-described charge transporting material are mixed and used. A method using a polymer having a charge transporting capability for the outermost surface layer is conceivable, and the latter method is preferable because a high-sensitivity photoconductor and a small increase in residual potential can be obtained.

  Preferred examples of the polymer having the charge transport layer ability include those having a group represented by the following structural formula (1) as a group having a charge transport ability in the polymer.

However, in the structural formula (1), Ar ₁ represents an arylene group which may have a substituent. Ar ₂ and Ar ₃ may be the same as or different from each other, and each represents an aryl group which may have a substituent.

  Such a group having a charge transporting ability is preferably added to a side chain of a polymer having high mechanical strength such as a polycarbonate resin and an acrylic resin, and the monomer can be easily produced, and the coating property and curability are also improved. It is particularly preferable to use an excellent acrylic resin.

  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 structural formula (1). Can be formed. The acrylic resin has a crosslinked structure by mixing a polyfunctional unsaturated carboxylic acid, preferably a tri- or higher functional unsaturated carboxylic acid, with the monofunctional unsaturated carboxylic acid having the group of the structural formula (1). When formed, it becomes a thermosetting polymer, and the mechanical strength of the surface layer becomes extremely high. The polyfunctional unsaturated carboxylic acid may be added with the group of the structural formula (1). However, since the production cost of the monomer is increased, the polyfunctional unsaturated carboxylic acid has the above structure. It is preferable to use a photocurable polyfunctional monomer without adding the group of the formula (1).

  Examples of the monofunctional unsaturated carboxylic acid having a group represented by the structural formula (1) include the following structural formula (2) or structural formula (3).

In the structural formulas (2) and (3), R ₁ is 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. An aryl group which may have a cyano group, a nitro group, an alkoxy group which may have a substituent, -COOR ₇ (wherein R ₇ is a hydrogen atom, an alkyl which may have a substituent) group, an optionally substituted aralkyl group, or substituted represent also aryl group), a halogenated carbonyl group, CONR 8 _R 9 _(provided that,, R ₈ and R ₉ are each They may be the same or different and have 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. Optionally substituted aryl group Represents).

In the structural formula (2) and the structural formula (3), Ar ₁ and Ar ₂ may be the same with each other or different, represent an arylene group optionally having a substituent.

In Structural Formula (2) and Structural Formula (3), Ar ₃ and Ar ₄ may be the same as or different from each other, and each represents an aryl group that may have a substituent.

  In the structural formulas (2) and (3), X has a single bond, an alkylene group which may have a substituent, a cycloalkylene group which may have a substituent, or a substituent. And an alkylene ether group, an oxygen atom, a sulfur atom, and a vinylene group which may be substituted.

  In the structural formulas (2) and (3), Z has an alkylene group which may have a substituent, an alkylene ether divalent group which may have a substituent, or a substituent. Represents an alkyleneoxycarbonyl divalent group which may be present.

  m and n each represents an integer of 0 to 3.

In the structural formulas (2) and (3), 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. Among the substituents of R _1, a hydrogen atom or a methyl group, it is particularly preferred.

Examples of the aryl group of Ar ₃ and Ar ₄ include a condensed polycyclic hydrocarbon group, a non-condensed cyclic hydrocarbon group, and a heterocyclic group.

  As the condensed polycyclic hydrocarbon group, those having 18 or less carbon atoms forming a ring are preferable. 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, pleyadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group, Examples include a chrycenyl group and a naphthacenyl group.

  Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether, diphenyl sulfone; biphenyl, polyphenyl, diphenyl alkane, diphenyl alkene, diphenyl alkyne. , Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene; ring assembly carbonization such as 9,9-diphenylfluorene And monovalent groups of hydrogen compounds.

  Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

  The content of the polyfunctional unsaturated carboxylic acid is preferably 5 to 75% by mass, more preferably 10 to 70% by mass, and still more preferably 20 to 60% by mass with respect to the entire outermost surface layer. When the content is less than 5% by mass, the mechanical strength of the outermost surface layer is insufficient, and when it exceeds 75% by mass, cracks are likely to occur when a strong force is applied to the outermost surface layer. Degradation may also occur easily.

  When an acrylic resin is used for the outermost 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 a surface layer. can do. 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.

  The outermost surface layer preferably contains metal fine particles, metal oxide fine particles, and other fine particles in order to increase the mechanical strength of the outermost surface layer. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, TiO, TiN, zinc oxide, indium oxide, and antimony oxide. Examples of the other fine particles include fluororesins such as polytetrafluoroethylene, silicone resins, or those obtained by dispersing an inorganic material in these resins for the purpose of improving wear resistance.

  Next, the electrostatic latent image can be formed, for example, by uniformly charging the surface of the image carrier and then exposing it imagewise, and can be performed by the electrostatic latent image forming means. . The electrostatic latent image forming unit includes 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 charger including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotron and scorotron.

  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 thereof 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.

  In the present invention, an optical back side system in which imagewise exposure is performed from the back side of the image carrier may be adopted.

<< Development process and development means >>
The developing step is a step of developing the electrostatic latent image using a toner or a 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 means 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, Preferable examples include those having at least a developing device capable of applying the toner or the developer to the electrostatic latent image in a contact or non-contact manner.

[toner]
The toner preferably has an average circularity of 0.93 to 1.00, and more preferably 0.95 to 0.99, which is an average value of the circularity SR represented by the following formula (1). This 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.

  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 image carrier is not damaged or worn.

  The circularity SR can be measured using, for example, a flow type particle image analyzer (FP1A-1000, manufactured by Toa Medical Electronics Co., Ltd.).

  First, 0.1 to 0.5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. Add ~ 0.5g. The suspension in which the sample is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the shape and particle size of the toner are measured by the above apparatus with the dispersion concentration being 3000 to 10000 / μl.

  The toner has a mass average particle diameter (D4) of preferably 3 to 10 μm, and more preferably 4 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 mass 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, and when it exceeds 10 μm, it is difficult to suppress scattering of characters and lines. is there.

  The toner has a mass average particle diameter (D4) to number average particle diameter (D1) ratio (D4 / D1) of preferably 1.00 to 1.40, and more preferably 1.00 to 1.30. The closer the ratio (D4 / D1) is to 1, the sharper the particle size distribution of the toner. In the range of (D4 / D1) from 1.00 to 1.40, selective development depending on the toner particle size. Since image quality 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. Further, when the toner particle diameter is uniform, the latent image dots are developed so as to be arranged densely and orderly, so that the dot reproducibility is excellent.

  Here, the mass 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-2 and Coulter Multisizer 2 (both manufactured by Coulter).

  First, 0.1 to 5 ml of a surfactant (preferably alkyl benzene sulfonate) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution. Here, the electrolytic solution is prepared by preparing an about 1% NaCl aqueous solution using primary sodium chloride, and for example, 1SOTON-2 (manufactured by Coulter) can be used. Here, 2 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 to 3 minutes, and the measurement device is used to measure the volume and number of toner particles or toner using a 100 μm aperture as an aperture. Volume distribution and number distribution are calculated. From the obtained distribution, the mass average particle diameter (D4) and the number average particle diameter (D1) of the toner can be obtained.

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm.

  As the toner having such a substantially spherical shape, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent is crosslinked in the presence of resin fine particles in an aqueous medium. It can be prepared by an extension reaction. The toner produced by this reaction can reduce the hot offset by curing the toner surface, and can prevent the fixing device from becoming dirty and appearing on the image.

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

  Examples of the polyester prepolymer (A) having an isocyanate group include a polycondensate of a polyol (1) and a polycarboxylic acid (2) and a polyester having an active hydrogen group, which is further reacted with a polyisocyanate (3). Is mentioned. 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), trivalent or higher polyol (1-2), (1-1) alone or (1-1) and a small amount of (1-2). Mixtures are 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 diols (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; bis Alkylene oxide phenol compound (ethylene oxide, propylene oxide, butylene oxide, etc.) adducts. 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.); (Trisphenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or higher polyphenols.

  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.

  As for the ratio of the polyol (1) and the polycarboxylic acid (2), the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH] is preferably 2/1 to 1/1. 5/1 to 1/1 is more preferable, and 1.3 / 1 to 1.02 / 1 is more preferable.

  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; phenols, oximes, polyisocyanates; What was blocked with caprolactam or the like; These may be used individually by 1 type and may use 2 or more types together.

  As for the ratio of the polyisocyanate (3), the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group is preferably 5/1 to 1/1. 1 to 1.2 / 1 is more preferable, and 2.5 / 1 to 1.5 / 1 is 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 becomes low, and hot offset resistance Sex worsens.

  The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is preferably 0.5 to 40% by mass, more preferably 1 to 30% by mass, and 2 to 20% by mass. Is more 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 number of isocyanate groups contained per molecule in the prepolymer (A) having the isocyanate group is preferably 1 or more on average, more preferably 1.5 to 3 on average, and 1.8 to 2.5 on average. Further preferred. 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 diamine (B1), trivalent or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and amino acids (B1) to (B5). What blocked the group (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′dimethyldicyclohexylmethane, diaminecyclohexane, Isophorone diamine etc.); and 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 amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. As (B6) which blocked the amino group of (B1) to (B5), a ketimine compound obtained from the amines of the above (B1) to (B5) and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), An oxazoline compound etc. are 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 (1) becomes low, and the hot offset resistance deteriorates.

  In the present invention, the polyester (1) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio between the urea bond content and the urethane bond content is preferably 100/0 to 10/90, more preferably 80/20 to 20/80, and even more preferably 60/40 to 30/70. 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, particularly the urea-modified polyester (1) can be produced. These urea-modified polyesters (1) are produced by a one-shot method or a prepolymer method. The mass average molecular weight of the urea-modified polyester (1) is preferably 10,000 or more, more preferably 20,000 to 10,000,000 and even more preferably 30,000 to 1,000,000. When the mass 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 is not particularly limited when the unmodified polyester (2) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the mass average molecular weight. (1) When used 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.

  In the present invention, not only the polyester (1) modified with a urea bond but also the polyester (2) not modified can be contained as a binder resin component together with the (1). The combined use of (2) improves the low-temperature fixability and gloss when used in a full-color device, and is therefore preferable to single use. Examples of (2) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (1) above, and preferred ones are also the same as (1). Further, (2) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, and may be modified with a urethane bond, for example. (1) and (2) are preferably at least partially compatible in terms of low-temperature fixability and hot offset resistance.

  Accordingly, the polyester component (1) and (2) preferably have similar compositions. In the case of containing (2), the mass ratio of (1) and (2) is preferably 5/95 to 80/20, more preferably 5/95 to 30/70, and further 5/95 to 25/75. 7/93 to 20/80 is particularly preferable. When the mass ratio of (1) is less than 5% by mass, the hot offset resistance is deteriorated, and it may be disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (2) is preferably 1,000 to 30,000, more preferably 1,500 to 10,000, and still more preferably 2,000 to 8,000. When the peak molecular weight is less than 1,000, the heat-resistant storage stability may be deteriorated, and when it exceeds 10,000, the low-temperature fixability may be deteriorated. The hydroxyl value of (2) is preferably 5 or more, more preferably 10 to 120, and still more preferably 20 to 80. If the hydroxyl value is less than 5, it may be disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. 1-30 are preferable and, as for the acid value of said (2), 5-20 are more preferable. By having an acid value, it tends to be negatively charged.

  The glass transition temperature (Tg) of the binder resin is preferably 50 to 70 ° C, and more preferably 55 to 65 ° C. When the glass transition temperature is less than 50 ° C., blocking of the toner during high temperature storage may deteriorate, 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 storage stability even when the glass transition point is low, as compared with known polyester-based toners.

As the storage elastic modulus of the binder resin, the temperature (TG ′) at which the measurement frequency is 20 Hz is 10,000 dyne / cm ² is preferably 100 ° C. or more, and more preferably 110 to 200 ° C. When the temperature (TG ′) is less than 100 ° C., the hot offset resistance may be deteriorated.

  As the viscosity of the binder resin, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is preferably 180 ° C. or less, and more preferably 90 to 160 ° C. When the temperature (Tη) exceeds 180 ° C., the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low-temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, and further preferably 20 ° C. or higher. The upper limit of the difference is not particularly limited. Moreover, 0-100 degreeC is preferable from the viewpoint of coexistence of heat-resistant storage stability and low-temperature fixability, 0-100 degreeC is more preferable, 10-90 degreeC is more preferable, and 20-80 degreeC is more preferable.

  The binder resin can be produced by the following method.

  First, the polyol (1) and the polycarboxylic acid (2) are produced at 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and reduced 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 40-140 degreeC, and the prepolymer (A) which has an isocyanate group is obtained. Further, (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester modified with a urea bond. When (3) is reacted and (A) and (B) are reacted, a solvent can be used as necessary.

  Usable solvents include, for example, aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.), Inactive to isocyanate (3) such as ethers (tetrahydrofuran, etc.).

  When the polyester (2) not modified with urea bond is used in combination, (2) is produced in the same manner as the polyester having a hydroxyl group, and this is dissolved in the solution after the completion of the reaction (1). , Mix.

  Further, the toner used in the present invention can be produced by the following method, but is not limited thereto.

  The toner may be formed by reacting a dispersion composed of a prepolymer (A) having an isocyanate group in an aqueous medium with (B), or using a urea-modified polyester (1) produced in advance. Good. As a method for stably forming a dispersion composed of urea-modified polyester (1) and prepolymer (A) in an aqueous medium, a toner raw material composed of urea-modified polyester (1) and prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force.

  The prepolymer (A) and other toner compositions (hereinafter also referred to as toner raw materials), colorants, colorant master batches, release agents, charge control agents, unmodified polyester resins, etc. 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 the miscible solvent 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 relative to 100 parts by mass of the toner composition containing the urea-modified polyester (1) and the prepolymer (A) is preferably 50 to 2000 parts by mass, and more preferably 100 to 1000 parts by mass. When the amount used is less than 50 parts by mass, the toner composition is not well dispersed, and toner particles having a predetermined particle size may not be obtained. When the amount used exceeds 2000 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. . In order to make the particle diameter of the dispersion 2 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, but is preferably 1000 to 30000 rpm, more preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. As temperature at the time of dispersion | distribution, 0-150 degreeC is preferable normally and 40-98 degreeC is more preferable. Higher temperatures are preferred in that the dispersion of the urea-modified polyester (1) or prepolymer (A) has a low viscosity and is easily dispersed.

  In the step of synthesizing the urea-modified polyester (1) from the prepolymer (A), the amine (B) may be added and reacted before the toner composition 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 alkylbenzene 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 perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (carbon number 6 -11) Oxy] -1-alkyl (carbon number 3-4) sodium sulfonate, 3- [omega-fluoroalkanoyl (carbon number 6-8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-20) carboxylic acid or metal salt thereof, perfluoroalkylcarboxylic acid (C7-13) or metal salt thereof, perfluoroalkyl (C4-12) sulfonic acid or metal salt thereof, perfluoro Octanesulfonic acid diethanolamide, N-propyl-N- (2- Droxyethyl) 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); Unidyne DS-101, DS-102 (manufactured by Daikin Industries); Megafac F-110, F-120, F-113, F-191, F-812, F-833 (large) Nippon Ink Chemical Co., Ltd.); Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products); 150 (manufactured by Neos).

  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, imidazoline, 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. . Among the cationic surfactants, aliphatic quaternary ammonium such as aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, perfluoroalkyl (6 to 10 carbon atoms) sulfonamidopropyltrimethylammonium salt, etc. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Commercially available products of the cationic surfactant include, for example, Surflon S-121 (manufactured by Asahi Glass Co., Ltd.); Florard FC-135 (manufactured by Sumitomo 3M Co.); Unidyne DS-202 (manufactured by Daikin Industries Ltd.), MegaFuck F-150, F-824 (manufactured by Dainippon Ink & Chemicals, Inc.); 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 hardly 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 hydroxyl groups, vinyl alcohol or ethers of vinyl alcohol, esters of vinyl alcohol and a compound containing a carboxyl group, amide compounds Alternatively, homopolymers or copolymers of these methylol compounds, chlorides, those having a nitrogen atom or a heterocyclic ring thereof, polyoxyethylenes, celluloses and the like can be mentioned.

  Examples of the acids include acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and the like. Examples of the (meth) acrylic monomer containing a hydroxyl group include β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, and γ-acrylate. Hydroxypropyl, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, Examples include glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide and the like. Examples of vinyl alcohol or ethers with vinyl alcohol include vinyl methyl ether, vinyl ethyl ether, and vinyl propyl ether. Examples of the esters of the compound containing vinyl alcohol and 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 the nitrogen atom or its heterocyclic ring 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, and hydroxypropyl cellulose.

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

  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 lower the viscosity of the toner composition, a solvent in which the urea-modified polyester (1) 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.

  Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, and 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.

  0-300 mass parts is preferable, as for the usage-amount of the solvent with respect to 100 mass parts of said prepolymers (A), 0-100 mass parts is more preferable, and 25-70 mass parts is more preferable. When a solvent is used, it is removed by heating under normal pressure or reduced pressure after elongation and / or crosslinking reaction.

  The elongation and / or cross-linking reaction time is selected depending on the reactivity depending on the combination of the isocyanate group structure of the prepolymer (A) and the amines (B). More preferred. The reaction temperature is preferably 0 to 150 ° C, more preferably 40 to 98 ° C. Furthermore, a known catalyst can be used as necessary. Specific examples 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 a 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 currents heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is 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. The classification operation may be performed after obtaining the powder after drying, but it is preferably performed in a liquid from the viewpoint of efficiency. 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 obtained toner powder after drying with different kinds of 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) a 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 to make it collide. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), Type 1 mill (manufactured by Nippon Pneumatic Co., Ltd.), with reduced pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron system ( Kawasaki Heavy Industries, Ltd.), automatic mortar and the like.

  As the colorant used in the toner, pigments and dyes conventionally used as toner colorants can be used. Specifically, carbon black, lamp black, iron black, ultramarine, nigrosine dye, Aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow G, rhodamine 6C lake, calco oil blue, chrome yellow, quinacridone red, benzidine yellow, rose bengal and the like can be used alone or in combination.

  Further, if necessary, in order to give the toner particles 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 alone or in combination in the toner particles. These components can also be used as a colorant component.

  The number average particle diameter of the colorant in the toner used in the present invention is preferably 0.5 μm or less, more preferably 0.4 μm or less, and further preferably 0.3 μm or less. 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, if there are many colorants having a particle size greater than 0.5 μm, the transmission of incident light is hindered or scattered, resulting in the brightness of the projected image of the OHP sheet and 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.

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

  As the binder resin used for kneading in advance, the resins exemplified as the binder resin for toner can be used as they are, but are not limited thereto.

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

  Further, 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 an organic solvent such as acetone, toluene, butanone, and water are used as the colorant. It is preferable from the viewpoint of dispersibility. 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.

  The toner preferably contains a release agent together with the binder resin and the colorant.

  The release agent is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbon (paraffin wax) And waxes containing carbonyl groups. 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); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylenediamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearylamide) Etc.); dialkyl ketones (distearyl ketone, etc.) and the like. Among these, polyalkanoic acid esters are particularly preferable.

  40-160 degreeC is preferable, as for melting | fusing point of the said mold release agent, 50-120 degreeC is more preferable, and 60-90 degreeC is further more preferable. If the melting point is less than 40 ° C., the heat resistant storage stability may be adversely affected, and if it exceeds 160 ° C., cold offset may easily occur during fixing at a low temperature.

  The melt viscosity of the release agent is preferably 5 to 1000 cps, more preferably 10 to 100 cps at a temperature 20 ° C. higher than the melting point. When the melt viscosity exceeds 1000 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 preferably 0 to 40% by mass, and more preferably 3 to 30% by mass.

  Further, a charge control agent may be contained in the toner as necessary in order to speed up the toner charge amount and its rise. 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, and metal salts of salicylic acid derivatives.

  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 a phenol-based condensate (both manufactured by Orient Chemical Industries); TP-302, TP-415 of a 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, boron complex LR-147 (all manufactured by Nippon Carlit Co., Ltd.), quinacridone, azo series Examples thereof include pigments and other polymer compounds having a functional group such as a sulfonic acid group, a carboxyl group, and a quaternary ammonium salt.

  The amount of the charge control agent added varies depending on the type of the binder resin, the presence or absence of the additive, the toner production method including the dispersion method, and the like, and cannot be uniquely defined, but with respect to 100 parts by mass of the binder resin. 0.1-10 mass parts is preferable and 0.2-5 mass parts is more preferable. When the addition amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction force with the developing roller is increased, the flowability of the developer is reduced, and the image The concentration may decrease. These charge control agents can be melted and kneaded together with a masterbatch and resin and then dissolved and dispersed, or they can be added directly when dissolved and dispersed in an organic solvent, or fixed after the toner particles are prepared on the toner surface. You may let them.

  Further, when the toner composition is dispersed in the aqueous medium during the toner production process, resin fine particles mainly for stabilizing the dispersion may be added.

  The resin fine particles may be any resin as long as it can form an aqueous dispersion, and may be a thermoplastic resin or a thermosetting resin. For example, vinyl resins, polyurethane resins, epoxy resins, polyester resins , 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 homopolymerizing or copolymerizing 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 heavy polymer is used. Examples thereof include styrene-acrylonitrile copolymer, styrene-maleic anhydride copolymer, and styrene- (meth) acrylic acid copolymer.

  As an external additive for assisting the fluidity, developability and chargeability of the toner particles, inorganic fine particles are suitable.

  Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, Examples thereof include chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and more preferably 5 nm to 500 nm. The specific surface area of the inorganic fine particles by BET method is preferably 20 to 500 m ² / g. The addition amount of the inorganic fine particles in the toner is preferably 0.01 to 5% by mass, and more preferably 0.01 to 2.0% by mass.

  Other polymer fine particles such as polystyrene, methacrylic acid ester and acrylic acid ester copolymer obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, polycondensation system such as silicone, benzoguanamine and nylon, thermosetting resin And polymer particles.

  A fluidizing agent can also 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, and modified silicone oil. Can be mentioned.

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

  By using such a toner, as described above, it is possible to form a high-quality toner image having excellent development stability.

  Further, the image forming apparatus of the present invention can be applied not only to the combined use with the above-described polymerization method toner 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.

  Examples of the binder resin used in the pulverized toner include styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, or a homopolymer of a substituted product thereof; styrene / p-chlorostyrene copolymer, styrene / propylene. Copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / acrylic Octyl acid copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / acrylonitrile copolymer Polymer, styrene / vinyl methyl ketone copolymer Styrene copolymers such as styrene / butadiene copolymer, styrene / isoprene copolymer, styrene / maleic acid copolymer; polymethyl acrylate, polybutyl acrylate, polymethyl methacrylate, polybutyl methacrylate, etc. Acrylic ester-based homopolymer or copolymer thereof; polyvinyl derivatives such as polyvinyl chloride and polyvinyl acetate; polyester-based polymers, polyurethane-based polymers, polyamide-based polymers, polyimide-based polymers, polyol-based polymers, Examples thereof include epoxy polymers, terpene polymers, aliphatic or alicyclic hydrocarbon resins, and aromatic petroleum resins. 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, cost, and the like, and further, polyester resins and polyol resins are preferable as those having good fixing characteristics. Particularly preferred.

  In the pulverized toner, together with these resin components, the colorant component, wax component, charge control component and the like as described above are premixed as necessary, and then kneaded at a temperature close to the melting temperature of the resin component, and then cooled. Thereafter, a toner may be prepared through a pulverizing and classifying step, and the external additive component may be appropriately 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 (photosensitive member), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is caused by the electric attractive force. It moves to the surface of the image carrier (photoreceptor). As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the image carrier (photoconductor).

  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 (photoreceptor) with the transfer charger using the visible image, 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 when performing 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, it is preferable to indicate the conductivity of a volume resistivity ^{1.0 × 10 5 ~1.0 × 10 11} Ω · cm. When the volume resistance 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 to the intermediate transfer member. If the toner image 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. May appear as an afterimage on other images.

As the intermediate transfer member, for example, a metal oxide such as tin oxide or indium oxide, a conductive particle such as carbon black, or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then extrusion-molded belt A cylindrical or cylindrical plastic can be used. In addition, the above-mentioned conductive particles and conductive polymer are added to a resin solution containing a thermal crosslinking reactive monomer or oligomer, if necessary, and subjected to centrifugal molding while heating to obtain an intermediate transfer member on an endless belt. You can also
When providing a surface layer on the intermediate transfer body, among the surface layer materials used for the above-described photoreceptor surface layer, the composition excluding the charge transport material is appropriately adjusted for resistance by using a conductive substance in combination, Can be used.

The transfer means (the primary transfer means and the secondary transfer means) includes at least a transfer device that peels and charges the visible image formed on the image carrier (photoconductor) to the recording medium side. It is preferable to have. 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 protective agent for an image carrier of the present invention to the surface of the image carrier after transfer.
As the protective layer forming means, the protective layer forming apparatus of the present invention described above can be used.

<< Fixing process 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.
The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, according to the purpose, for example, a known optical fixing device may be used together with or instead of the fixing step and the fixing unit.
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.

  The cleaning step is a step of removing the electrophotographic 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, and may be selected from known cleaners as long as it can remove the electrophotographic toner remaining on the image carrier. For example, a magnetic brush cleaner, Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

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, A well-known conveyance means etc. are mentioned.

  The control means is a process for controlling the steps, and can be suitably performed by the control means.

  Here, FIG. 3 is a cross-sectional view showing an example of the image forming apparatus 100 including the protective layer forming apparatus of the present invention.

  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 a sequencer and a computer.

  Around the drum-shaped image carrier (1Y), (1M), (1C), (1K), a protective layer forming device (2), a charging device (3), a latent image forming device (8), and a developing device, respectively. (5) The transfer device (6) and the cleaning device (4) are arranged, and image formation is performed by the following operation.

  Next, a series of processes for image formation will be described using a negative-positive process.

  An image carrier represented by a photoconductor (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 device 3 having a charging member.

  When the image carrier is charged by the charging device, the image carrier (1Y), (1M), (1C), (1K) is applied to a charging member from a voltage application mechanism (not shown) to a desired potential. A voltage of an appropriate magnitude suitable for charging the battery or a charging voltage obtained by superimposing an AC voltage thereon is applied.

  The charged image carriers (1Y), (1M), (1C), and (1K) form latent images (exposure portion potentials) with laser light emitted by a latent image forming device (8) such as a laser optical system. The absolute value is lower than the absolute value of the non-exposed portion potential).

  Laser light is emitted from a semiconductor laser and rotated on the surface of the image carrier (1Y) (1M), (1C), (1K) by a polygonal polygon mirror (polygon) that rotates at high speed. Scan in the axial direction.

  The latent image formed in this manner is developed with a developer composed of toner particles or a mixture of toner particles and carrier particles supplied onto a developing sleeve which is a developer carrying member in the developing device 5, and toner A visual image is formed.

  At the time of developing the latent image, a voltage application mechanism (not shown) is applied to the developing sleeve between the exposed portion and the non-exposed portion of the image carrier (1Y), (1M), (1C), (1K). A voltage having a large magnitude or a developing bias in which an AC voltage is superimposed on the voltage 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 member (60) by the transfer device (6) and supplied. The toner image is transferred onto a recording medium such as paper fed from the paper mechanism (200).
At this time, it is preferable that a potential having a polarity opposite to the polarity of toner charging is applied to the transfer device (6) as a transfer bias. Thereafter, the intermediate transfer member (60) is separated from the image carrier to obtain a transfer image.

  The toner particles remaining on the image carrier are collected by the cleaning member into the toner collection chamber in the cleaning device (4).

  As the image forming apparatus, an apparatus in which a plurality of the developing devices described above are arranged is used, and a plurality of toner images, which are sequentially produced by the plurality of developing devices, are sequentially transferred onto a transfer material, and then sent to a fixing mechanism to be heated. Even after a plurality of toner images prepared in the same manner are sequentially sequentially transferred onto an intermediate transfer member and then transferred to a recording medium such as paper, Similarly, a fixing device may be used.

  The charging device (3) is preferably a charging device disposed in contact with or close to the surface of the image carrier, and a discharge wire is used. This makes it possible to significantly suppress the amount of ozone generated during charging as compared with a corona discharger called a so-called corotron or scorotron.

  In a charging device that charges such a charging member in contact with or close to the surface of the image carrier, discharge is performed in the region near the surface of the image carrier as described above, so that electrical stress is applied to the image carrier. Tends to grow. However, by using the protective layer forming apparatus using the protective agent for an image carrier of the present invention, the image carrier can be maintained for a long time without deterioration. Fluctuations can be greatly suppressed, and stable image quality can be ensured.

  As described above, the image forming apparatus of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, and has a configuration in which fluctuations in charging performance to the image carrier are highly suppressed. By using in combination with the toner of the constitution, an extremely high quality image can be stably formed over a long period of time.

<Process cartridge>
The process cartridge of the present invention comprises at least the image carrier and the protective layer forming means of the present invention, and further, charging means, exposure means, developing means, transfer means, cleaning means, charge eliminating means as necessary. And other means.

  The process cartridge of the present invention can be detachably provided in various electrophotographic apparatuses, and is preferably provided detachably in the above-described image forming apparatus of the present invention.

  The process cartridge includes a protective layer forming device (2) disposed opposite to the photosensitive drum (1), which is an image carrier (1), an image carrier protective agent (21), and a protective agent supply member. (22), a pressing force applying member (23), a protective layer forming member (24), and the like.

  Further, the image carrier (1) has a surface on which the protective agent for the image carrier and the toner component partially deteriorated after the transfer process remain, but the surface residue is cleaned by the cleaning member (41). To be cleaned.

  2 and 3, the cleaning member (4) is in contact at an angle similar to a so-called counter type (leading type).

  The protective agent for image carrier (21) is supplied from the protective agent supply member (22) to the image carrier surface from which the residual toner on the surface and the deteriorated protective agent for image carrier have been removed by the cleaning mechanism, A film-like protective layer is formed by the protective layer forming member (24). At this time, since the necessary and sufficient amount of the protective agent for the image carrier used in the present invention can be stably supplied to the surface of the image carrier with good controllability, the surface of the image carrier can be efficiently protected and used for a long period of time. Can prevent the deterioration of the image carrier itself.

  The image carrier having the protective layer formed in this way is charged, and then an electrostatic ray image is formed by exposure L such as a laser, and developed by the developing device (5) to be visualized, and the image bearing member outside the process cartridge is formed. The image is transferred to the recording medium (7) by the transfer roller 6 or the like.

  As described above, the process cartridge of the present invention has an excellent tolerance for fluctuations in the surface state of the image carrier, and has a configuration in which fluctuations in charging performance to the image carrier are highly suppressed. By using in combination with toner, it is possible to stably form an extremely high quality image over a long period of time.

Examples of the present invention will be described below, but the present invention is not limited to these examples.
<Method for Producing Protective Agent 1 for Image Carrier>
45 g of zinc stearate (average particle size 30 μm) is weighed, and the measured protective agent formulation 1 composition is put into an aluminum mold having an inner dimension of depth 40 mm × width 8 mm × length 350 mm. The lid was closed so as not to leak, and vibration was applied to make the filled powder uniform. Next, the lid of the mold was removed, and the powder compact was molded by pressing with a pressing mold so that the height of the filling was 16 mm. Similarly, ten image carrier protective agents 1 (protective agent blocks, hereinafter the same) were produced.

Since the true specific gravity of zinc stearate is 1.10, if the charged zinc stearate is used 100%, the porosity of the produced image carrier protective agent 1 is:
{1-45 / (4.0 × 0.8 × 35.0 × 1.10)} × 100 = 8.7%
It is.
When the porosity was measured according to the following procedure, it was 8.8%.
Next, the porosity of the image carrier protective agent was measured by the following procedure.
1. The powder compacted body of the image-bearing member protective agent, accurately dimensioned using calipers and straightedge to calculate the apparent volume V (cm ^3).
2. The weight W (g) of the image bearing member protective agent is measured.
3. The protective agent for the image bearing member is coarsely pulverized, and a part thereof is precisely weighed.
4). The true specific gravity ρ (g / cm ³ ) of the accurately weighed image carrier protective agent sample is measured using an air comparison specific gravity meter.
5). From each measured value, the porosity is calculated according to the following equation.
{Porosity (%) = 100 × (V−W / ρ) / V}
The series of characteristic measurements was performed in a laboratory environment of about 20 ° C. and 50% RH.

Example 1
An epoxy adhesive having a viscosity of 3300 cP (epoxy resin AW-106 (with HV-953U), manufactured by Nagase ChemteX Corp.) was applied to the protective agent 1 for the image carrier and attached to a 2 mm thick iron base material. The adhesive was cured with the image carrier protective agent down and the iron substrate up.
When a cross section near the adhesion surface of the image bearing member protective agent 1 to the base material was confirmed with a microscope, the adhesive penetrated into the pores of the image bearing member protective agent at a maximum of 100 μm and an average of 40 μm.
Four process cartridges in which image carrier protective agent 1 is similarly bonded to a base material are prepared, and a process cartridge modified to have the configuration shown in FIG. 1 is formed as an image forming apparatus (color MFP 1mag1o Neo C600, manufactured by Ricoh Co., Ltd.). And a continuous image drawing test of an A4 size plate and an image area ratio of 6% original with 50,000 sheets was conducted. When the presence or absence of image abnormality before and after the test was confirmed in a room temperature and humidity environment of 20 ° C. and 50% RH, a high-quality image was obtained.
(Comparative Example 1)
An image forming apparatus was prepared and image formation was performed in the same manner as in Example 1 except that the image bearing member protective agent 1 was fixed to a substrate using a pressure-sensitive double-sided adhesive tape (Nitto Denko No. 5000NS). When 4500 sheets of images were formed, abnormal noise began to occur. Therefore, when image formation was stopped and the process cartridge was disassembled, the protective agent for the image carrier of the yellow station process cartridge was removed from the substrate. It was peeled off.

<Protective agents 2-8 for image carrier>
Zinc stearate (average particle size 30 μm) 60 wt%, zinc stearate (average particle size 15 μm) 32 wt%, boron nitride (average particle size 30 μm) 7.5 wt%, alumina (average particle size 0.2 μm) 0 .5% by weight was mixed. Mixing was performed twice for 3 seconds using a wonder blender (WB-1, distributor: Osaka Chemical Co., Ltd.) at a rotational speed of 25000 rpm.
The mixed protective agent was put into the mold used in Example 1 to prepare an image carrier protective agent having a thickness of 8 mm. The porosity of the image carrier protective agent (protective agent block) produced by changing the input amount was measured in the same manner as in Example 1.

  Further, the above mixture was heated and melted, put into an aluminum mold, and cooled to produce a protective agent 8 for an image carrier having a size of 40 mm × 16 mm × 350 mm.

(Example 2, Comparative Examples 2 and 3)
In Example 1, the molecular weight of the epoxy resin resin is adjusted so that the viscosity is 1600 cP, and the protective agents 2 and 4 for the image carrier are bonded and cured, and each is mounted on four sets of process cartridges. Produced.
Further, an image carrier was prepared by fixing the image bearing member protective agent 8 to a base material using a pressure-sensitive double-sided adhesive tape (Nitto Denko No. 5000NS).
As in Example 1, when 50,000 sheets of images were formed in a room temperature and normal humidity environment of 20 ° C. and 50% RH, the image after the image formation was confirmed. The image carrier protective agent 2 and the image carrier protective agent 8 were used. In the image of the image forming apparatus, a streak-like abnormal image was generated on the entire surface of the image. When the process cartridge of each image forming apparatus is disassembled, the protective agent for the image carrier of many process cartridges is colored in a streak shape, and it is 1R measurement that the coloring is a result of the toner being fixed. I understood.
On the other hand, in the image forming apparatus using the image carrier protecting agent 4, a high-quality image was obtained.

(Example 3, Comparative Example 4)
In Example 1, the molecular weight of the epoxy resin resin was adjusted to a viscosity of 5000 cP, and the image carrier protective agent was fixed to the substrate in the same manner except that the image carrier protective agents 6 and 7 were used.
An attempt was made to mount the image carrier protective agent fixed to the base material on the process cartridge. When the image carrier protective agent 6 was used, four process cartridges could be produced without problems. In the case of using the carrier protective agent 7, part of the image carrier protective agent is missing in two process cartridges during the production of the process cartridge, and one of them breaks the image carrier protective agent. It was.
When an image was formed on an image forming apparatus equipped with a process cartridge using the image carrier protecting agent 6 and 100,000 sheets were formed in the same manner as in Example 1, a high-quality image was obtained.

<Protective agent 3 for image carrier>
Zinc stearate (average particle size 30 μm) 60% by weight, zinc stearate (average particle size 15 μm) 32% by weight, talc (average particle size 32 μm) 7.5% by weight, alumina (average particle size 0.2 μm) 5% by weight was mixed. Mixing was performed twice for 3 seconds at a rotational speed of 25000 rpm using a wonder blender (WB-1, distributor: Osaka Chemical Co., Ltd.).
The mixed protective agent was put into the mold used in Example 1 to prepare an image carrier protective agent having a thickness of 8 mm. When the porosity of the protective agent for an image carrier produced by changing the input amount was measured in the same manner as in Example 1, an image carrier 3 having a porosity of 8.8% was obtained.

<Protective agent 9 for image carrier>
Zinc stearate was heated and melted, put into an aluminum mold, and cooled to produce 40 mm × 16 mm × 350 mm protective agent 9 for image carrier.

(Examples 4, 5 and Comparative Example 5)
In Example 1, an image carrier protective agent was prepared in the same manner as in Example 1 except that the image carrier protective agents 3 and 5 were used, and mounted on a process cartridge to prepare an image forming apparatus.
The image carrier protective agent 9 was fixed to a pressure-sensitive double-sided adhesive tape (Nitto Denko No. 5000NS) to produce an image carrier protective agent, which was mounted on a process cartridge to produce an image forming apparatus.
Each image forming apparatus was subjected to a continuous image drawing test of 100,000 sheets of an A4 size plate and an image area ratio of 7%. The presence or absence of image abnormality before and after the test was confirmed by checking the image in a normal temperature and humidity environment of 20 ° C. and 50% RH in a low temperature and low humidity environment of 10 ° C. and 25% RH. All the images of the image forming apparatus used had high image quality, but the image forming apparatus using the image carrier protective agent 9 was an image of 20 ° C. and 50% RH, and a thin streak-like abnormal image was obtained. As can be seen, a clear streak-like abnormal image was obtained at 10 ° C. and 25% RH.

It is the schematic which shows an example of the protective layer forming apparatus of this invention of the state with which the image forming apparatus of this invention was mounted | worn. It is sectional drawing which shows an example of the image forming apparatus which comprises the protective layer forming apparatus of this invention. It is the schematic for demonstrating the outline of the example of a process cartridge structure using the protective layer forming apparatus of this invention. FIG. 2 is a schematic view of the periphery of an image carrier protective agent block when the image carrier protective agent block of the present invention is used.

Explanation of symbols

[Figure 1]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum which is an image carrier 2 Protective layer forming apparatus 21 Protective agent 22 for image carriers Protective agent supply member 23 Pressing force applying member 24 Protective layer forming member 3 Charging roller 4 Cleaning mechanism 41 Cleaning member 42 Cleaning pressing mechanism [ Figure 2]
DESCRIPTION OF SYMBOLS 1 Image carrier 2 Protection layer formation apparatus 3 Charging means 4 Cleaning means 5 Development means 6 Transfer roller 7 Image receiving medium 21 Image carrier protection agent 22 Protection agent supply member 23 Base material 24 Protection layer formation member 41 Cleaning blade 42 Blade pressing Mechanism 51 Developer carrying roller 52 Developer supply roller 53 Developer stirring roller L Exposure means [FIG. 3]
1Y, 1M, 1C, 1K Drum-shaped image carrier 2 Protective layer forming device 3 Charging device 4 Cleaning device 5 Developing device 6 Transfer device 8 Latent image forming device 10 Color toner image forming unit 60 Intermediate transfer member 100 Image forming device 200 Paper feed mechanism

Claims (8)

  At least a protective agent block formed by molding a surface protective agent for an electrophotographic image carrier into a block shape, and a protective agent supply for supplying a powdery protective agent separated from the protective agent block to the surface of the image carrier In the protective layer forming apparatus having a member and a pressing force applying member that presses and contacts the protective agent block against the protective agent supply member, the protective agent block is a porous body having a porosity of 2 to 15% by volume And the surface opposite to the surface in contact with the pressing force applying member is fixed to the base material supporting the protective agent block, and the pores on the surface where the protective agent block is fixed to the base material, The protective agent layer forming apparatus, wherein an adhesive for fixing the protective agent block is present on the substrate.   The protective agent layer forming apparatus according to claim 1, wherein the adhesive is applied to the protective agent block and the base material in a viscosity state of 1000 to 50000 cP, and adheres the protective agent block and the base material. .   The protective agent layer forming apparatus according to claim 1, wherein the protective agent block is mainly composed of metal soap. 4. The protective agent layer forming apparatus according to claim 1, wherein the protective agent block further contains a powder of inorganic material particles.   The protective agent layer forming apparatus according to claim 4, wherein the powder of the inorganic material particles contains talc and boron nitride.   A process cartridge using the protective agent layer forming apparatus according to claim 1.   An image forming apparatus using the protective agent layer forming apparatus according to claim 1.   An image forming apparatus using the process cartridge according to claim 6.

Images