JP5186803B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus, and as a reference technique of the present invention, a protective agent bar for protecting the surface of an image carrier, in particular, an image carrier protective agent bar used for image formation using an electrophotographic system, and an image carrier. protective layer forming device for forming a protective layer with a protective agent to the body surface, the process cartridge is relates to an image forming method using the image-bearing member protecting agent bar.

Up to now, in copiers that require high speed and image reproducibility, and multi-function machines based on this, two components are required due to the requirements of toner particle charging stability, rise-up performance, long-term image quality stability, etc. Many developing systems have been adopted, and one-component developing systems have been often used for small printers, facsimiles, and the like, which have great demands for space saving and cost reduction.
In particular, in recent years, colorization of output images has progressed, and the demand for higher image quality and stabilization of image quality has become stronger than ever.
In order to improve the image quality, the average particle diameter of the toner is reduced, and the shape of the particles is not rounded and becomes more round.
These electrophotographic image forming apparatuses are uniformly charged while rotating an image carrier having a drum shape or a belt shape, generally a photosensitive member, regardless of the development method, and laser light or the like. To form a latent image pattern on the image bearing member, which is visualized by a developing device, and further transferred onto a transfer medium.

Further, the toner component that has not been transferred remains on the image carrier after the toner image is transferred to the transfer medium. When these residues are conveyed to the charging process as they are, it is often the case that the uniform charging of the image carrier is hindered. The components and the like are removed in a cleaning process to make the surface of the image carrier sufficiently clean, and then charging is performed.
As described above, the surface of the image carrier is subjected to various physical stresses and electrical stresses in various processes such as charging, development, transfer, and cleaning, and the surface state changes as the usage time elapses.
Of these stresses, it is known that the stress due to friction in the cleaning process causes the image carrier to wear and causes scratches. In order to solve this problem, many proposals have been made so far regarding various lubricants and methods for supplying lubricant components and forming films in order to reduce the frictional force between the image carrier and the cleaning member.

In order to extend the life of the photoreceptor and the cleaning blade, it has been proposed to supply a solid lubricant mainly composed of zinc stearate to the surface of the photoreceptor to form a lubricant film on the surface of the photoreceptor (for example, Patent Document 1). 2).
When using metal soap such as zinc stearate as a lubricant, stick a metal soap bar to a metal plate base with double-sided adhesive tape and fix it, and rub a brush against the metal soap bar. The powder was made to adhere to a photoconductor and stretched on the photoconductor with a blade or the like.
When the AC charging method is used for charging, various substances adhere to the charging roller, and the substances adhere to the charging roller, thereby partially increasing the resistance of the charging roller and causing the charging failure of that part. It was easy to occur. This partial change in the resistance of the charging roller is closely related to the supply amount of zinc stearate, and the change in the resistance of the charging roller becomes large when the supply amount of zinc stearate is large. This is because when the particles on the photoreceptor reach just below the charging roller, the particles adhere to the charging roller by electrostatic force. The adhesion of the particles does not partially increase the resistance of the charging roller, but the metal soap adheres to the charging roller and melts when it receives AC charging energy, and is fixed while entraining the toner component. This occurs when the resistance of the roller changes.
Therefore, in the electrophotographic process using metal soap, uneven charging due to a change in the resistance of the charging roller has been the biggest cause of failure.

On the other hand, the use of lubricating substances other than metal soaps is also being studied.
For example, an image forming apparatus that forms an image while applying higher alcohol on a photoconductor is disclosed (for example, see Patent Document 3). When these higher alcohols are used, the cleaning performance of the residual toner on the photoconductor is remarkably improved, but the friction between the photoconductor and the cleaning blade is relatively high, and the effect of improving photoconductor wear is not so high.
In contrast, when an image is formed while a protective agent mainly composed of paraffin is applied on the photoreceptor, not only the cleaning performance of the photoreceptor is improved, but also the photoreceptor is worn due to friction with the cleaning blade. It has been found that the protective agent significantly reduces the oxidation of the photoreceptor due to AC charging.
However, even if paraffin is supplied onto the photoreceptor and pressure is applied by a blade or a brush, the ability to extend thinly on the photoreceptor is poor, so it is difficult to uniformly coat the photoreceptor. On the other hand, the portion coated with paraffin is suppressed from oxidation due to AC charging, whereas the portion not coated with the protective agent proceeds with oxidation due to AC charging, so that unevenness in image density tends to occur.

  In order to supply a protective agent mainly composed of paraffin to a photoconductor, generally, the protective agent processed into a rod shape (this is called a protective agent bar) is rubbed with a brush and the protective agent is scraped off and supplied to the photoconductor. Was. In order to reduce the unevenness of the protective agent on the photoconductor, the amount of scraping may be increased by rubbing the brush, and the pressure for rubbing the brush against the protective agent bar mainly composed of paraffin may be increased. However, if the pressure of the brush is too high, when the toner is held on the brush, the toner melts by the pressure of the brush and the protective agent, and a toner fixing film is formed on the surface of the protective agent. In other words, the photosensitive member cannot be protected.

On the other hand, an image forming apparatus using a fluororesin such as polytetrafluoroethylene as a protective agent is disclosed as another protective agent (see, for example, Patent Document 4). A fluororesin is a material that is chemically and thermally stable among organic substances and has a low coefficient of friction, and can be an excellent protective agent if it is uniformly coated on a photoreceptor.
However, in Patent Document 4, since a brush is rubbed against a dense polytetrafluoroethylene film, the rate at which the polytetrafluoroethylene is scraped is slow, so that a sufficient amount of polytetrafluoroethylene is supplied onto the photoreceptor. As a result, the photoconductor could not be protected.

Japanese Patent Publication No.51-22380 JP 2004-333961 A JP 2005-274737 A JP 2000-162938 A

In view of the above-described problems, the present invention increases the supply amount of the protective agent containing paraffin, so that the toner does not adhere to the protective agent bar, and a sufficient amount of protective agent is provided on the photoreceptor. The present invention provides an image forming apparatus having a protective agent bar having a high ability to protect a photosensitive member by supplying a high-quality image without image abnormality, and a protective layer forming apparatus using the same. Objective.

In the first aspect of the present invention, the protective agent supply member having a protective agent supply member that can come into contact with the image carrier and a protective agent bar formed by the protective agent for protecting the surface of the image carrier is formed by the protective agent supply member . by pressing a certain application brush, the protective agent is shifted to the protective agent supplying member, a protective layer supplies the coating brush migrated the protective agent rubs the surface of the image bearing member to said image bearing member in the image forming apparatus, the protective agent is at least a paraffin melting temperature 92 ° C. to 124 ° C., number average particle diameter 0 having a charging roller charging voltage shape forming device and an AC voltage are superimposed is applied. 3 μm to 55 μm of polytetrafluoroethylene particles , and the content of the polytetrafluoroethylene particles is 23.1 wt% to 35.5 wt% .

According to the present invention, a protective agent bar capable of forming a high-quality image without an abnormal image and having a high ability to protect a photoreceptor without toner sticking to the protective agent bar, and a protective layer using the same it is possible to provide an image forming apparatus having a shape forming device.

The inventors of the present invention have examined whether or not the protective agent can be removed without increasing the pressure of the brush when the brush is rubbed against the protective agent bar containing paraffin. It was found that a protective agent can be supplied if However, when the unevenness of the surface of the protective agent bar disappeared, the supply rate of the protective agent decreased, and it was found that it was important how to continue to provide unevenness on the surface of the protective agent bar. As a result of the accumulation, particles that are almost incompatible with paraffin are easily detached from the protective agent when the brush is rubbed against the protective agent bar, and the surface of the protective agent bar is uneven. I realized that it continues making, was examined particles hardly compatible with paraffin, fluorocarbon resin particles, hardly compatible with paraffin, readily found to detach from the protective agent bar, according to the present invention The protective agent bar was used in the image forming apparatus .
That is, the present invention is an image forming apparatus using a protective agent bar containing at least paraffin and fluorine resin particles for supplying a protective agent for protecting an image carrier of the image forming apparatus .

As the fluororesin particles used for the protective material bar, polytetrafluoroethylene (PTFE), polyperfluoroalkyl ether (PFA), perfluoroethylene-perfluoropropylene copolymer (FEP), polyvinylidene fluoride (PVdF), An ethylene-tetrafluoroethylene copolymer (ETFE) can be exemplified, and polytetrafluoroethylene (PTFE) is most preferable.
The number average particle diameter of the fluororesin particles used for the protective material bar is 0.1 to 50 μm, preferably 0.2 to 40 μm, and more preferably 0.3 to 30 μm. When the number average particle diameter of the fluororesin particles is less than 0.1 μm, the unevenness formed when the fluororesin is detached from the protective agent bar is small, and it is difficult to increase the rate of supplying the protective agent to the photoreceptor. If the number average particle size of the fluororesin particles is 50 μm or more, the detached protective agent is liable to cause image defects when it enters development or transfer, which is not preferable.

The content of the fluororesin particles used in the protective material bar is 10 to 60% by weight, preferably 15 to 50% by weight, and more preferably 20 to 40% by weight. When the content of the fluororesin particles is 10% by weight or less, the ability to supply the protective agent is low, which is not preferable. When the content of the fluororesin particles is larger than 60% by weight, a protective agent bar having a uniform composition is manufactured. Is difficult and undesirable.
As the paraffin used for the protective material bar, the main component is paraffin having a melting point of 60 ° C to 130 ° C, preferably 65 ° C to 125 ° C, and more preferably 70 ° C to 120 ° C. If the melting point of paraffin is 60 ° C. or lower, deformation due to storage at high temperature is likely to occur, and toner fixation on the protective agent bar is easily accelerated, which is not preferable. If the melting temperature of paraffin is 130 ° C. or higher, the coating performance on the photoreceptor is remarkably lowered, which is not preferable. The paraffin may be used by mixing not only one kind but also different kinds of paraffin.
The proportion of paraffin in the protective agent used in the protective agent bar is 40 to 90% by weight, preferably 50 to 85% by weight, and more preferably 60 to 80% by weight. When the ratio of paraffin is 40% by weight or less, the function as a protective agent is low, and the photoconductor is easily worn by image formation, which is not preferable. If the ratio of paraffin is 90% by weight or more, it is difficult and difficult for paraffin to cover the surface of the photoreceptor.

Substances other than paraffin and fluororesin used in the protective agent bar include amphiphilic organic compounds, aliphatic unsaturated hydrocarbons, alicyclic saturated hydrocarbons, alicyclic unsaturated hydrocarbons and aromatic hydrocarbons. In addition to the classified hydrocarbons, examples include, but are not limited to, silicone resins such as fluorine waxes, polymethyl silicone, polymethyl phenyl silicone, and silicone waxes. By incorporating a protective compound into the protective compound, the coating property of the protective agent is improved, and in particular, the alicyclic saturated hydrocarbon such as cyclic polyolefin forms a protective agent on the photoreceptor. It can be coated and is particularly preferred. These compounds other than paraffin may be used not only in one kind but also in a mixture of many kinds.
Examples of alicyclic saturated hydrocarbons include cycloparaffins and cyclic polyolefins, and cyclic polyolefins are particularly preferred because they have the effect of stretching paraffin on the photoreceptor.

Amphiphilic organic compounds are classified into anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, and composites thereof. Since the image carrier protective agent forms a protective agent layer on the image carrier as described above and undergoes an image forming process, it is necessary not to adversely affect the electrical characteristics of the image carrier. is there.
By using a nonionic surfactant as an amphiphilic organic compound, the surfactant itself does not dissociate, so even if the usage environment, especially humidity, changes significantly, air discharge etc. Therefore, the image quality can be maintained at a high level.
The nonionic surfactant is preferably an esterified product of an alkyl carboxylic acid of the chemical formula (1) and a polyhydric alcohol.

However, n in a formula shows the integer of 15-35.
By using a linear alkyl carboxylic acid as the alkyl carboxylic acid of the chemical formula (1), the hydrophobic portion of the amphiphilic organic compound can be easily arranged on the surface of the image carrier on which the amphiphilic organic compound is adsorbed, This is a preferred embodiment because the adsorption density on the surface of the carrier is particularly high.
The alkyl carboxylic acid ester in one molecule is hydrophobic, and the larger the number, the more the dissociable substances generated by air discharge are prevented from adsorbing on the surface of the image carrier, and the surface of the image carrier in the charged region. It is effective to reduce the electrical stress on. However, if the proportion of the alkyl carboxylic acid ester is too large, the portion of the polyhydric alcohol that exhibits hydrophilicity is obscured and sufficient adsorption performance may not be exhibited depending on the surface state of the image carrier. .
Therefore, the average number of ester bonds per molecule of the amphiphilic organic compound is preferably 1 to 3.
The average number of ester bonds per molecule of these amphiphilic organic compounds can be adjusted by selecting one or more from a plurality of amphiphilic organic compounds having different numbers of ester bonds.

Examples of the amphiphilic organic compound include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant as described above.
Examples of anionic surfactants include alkylbenzene sulfonate, α-olefin sulfonate, alkane sulfonate, alkyl sulfate, alkyl polyoxyethylene sulfate, alkyl phosphate, long chain fatty acid salt, α -Anion (anion) at the end of the hydrophobic site, such as sulfo fatty acid ester salt and alkyl ether sulfate, and alkali metal ions such as sodium and potassium, and alkaline earth metal ions such as magnesium and calcium , Compounds in which metal ions such as aluminum and zinc, ammonium ions, and the like are bonded.
Examples of cationic surfactants include a cation (cation) at the end of a hydrophobic site, such as alkyltrimethylammonium salt, dialkylmethylammonium salt, alkyldimethylbenzylammonium salt, etc., and chlorine, fluorine , Bromine and the like, and compounds in which phosphate ions, nitrate ions, sulfate ions, thiosulfate ions, carbonate ions, hydroxide ions, and the like are bonded.

Examples of amphoteric surfactants include dimethylalkylamine oxide, N-alkylbetaines, imidazoline derivatives, alkyl amino acids and the like.
Examples of nonionic surfactants include alcohol compounds such as long-chain alkyl alcohols, alkyl polyoxyethylene ethers, polyoxyethylene alkyl phenyl ethers, fatty acid diethanolamides, alkyl polyglucooxides, polyoxyethylene sorbitan alkyl esters, ethers Examples thereof include compounds and amide compounds. In addition, long-chain alkyl carboxylic acids such as lauric acid, palmitic acid, stearic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, and melicic acid, and polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, erythritol, and hexitol And ester compounds with these partial anhydrides are also preferred.

  More specific examples of ester compounds include glyceryl monostearate, glyceryl distearate, glyceryl monopartic acid, glyceryl dilaurate, glyceryl trilaurate, glyceryl dipartimate, glyceryl tripartinate, glyceryl dimyristate, trimyristate Glyceryl palmitate, glyceryl stearate, glyceryl monoarachidate, glyceryl diarachidate, glyceryl monobehenate, glyceryl stearate, glyceryl stearate, glyceryl monomontanate, and glyceryl monomelinate Sorbitan monostearate, sorbitan tristearate, sorbitan monopartitic acid, sorbitan dipartitic acid, Sorbitan lipartinate, sorbitan dimyristate, sorbitan trimyristate, sorbitan palmitate stearate, sorbitan monoarachidate, sorbitan diarachidate, sorbitan monobehenate, sorbitan behenate stearate, sorbitan stearate sorbitan monomontanate, monomelicine Examples of the alkyl carboxylic acid sorbitan such as sorbitan acid and the substitution thereof are not limited thereto.

Moreover, these amphiphilic organic compounds may use a single kind, and may use multiple types together.
Furthermore, you may make it contain in filler protective agents, such as a metal oxide, a silicic acid compound, and a mica, depending on the case.
Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a schematic view of a protective layer forming device configured according to the present invention.
In the figure, reference numeral 1 denotes a photosensitive drum, 2 denotes a protective layer forming device, 3 denotes a charging roller, 4 denotes a cleaning mechanism, 21 denotes an image carrier protective agent, 22 denotes a protective agent supply member, 23 denotes a pressing force applying mechanism, 24 Denotes a protective layer forming mechanism, 41 denotes a cleaning member, and 42 denotes a cleaning pressing mechanism.
The protective layer forming apparatus 2 disposed facing the photosensitive drum 1 serving as an image carrier includes an image carrier protective agent 21, a protective agent supply member 22, a pressing force applying mechanism 23, a protective layer forming mechanism 24, and the like. Mainly composed.
Image-bearing member protecting agent 21 according to the present invention, by a pressing force from the pressing force imparting mechanism 23, for example, contact the brush-like protective agent supplying member 22. The protective agent supply member 22 rotates and rubs with the image carrier 1 with a linear velocity difference. At this time, the image carrier protective agent held on the surface of the protective agent supply member is supplied to the surface of the image carrier.
Since the image carrier protective agent supplied to the surface of the image carrier may not be a sufficient protective layer upon supply depending on the selection of the material type, for example, a blade-like member is used to form a more uniform protective layer. The protective layer is formed into a thin layer by a protective layer forming mechanism having a protective layer.

The image carrier on which the protective layer is formed is formed by, for example, bringing a charging roller 3 to which a DC voltage or a voltage obtained by superimposing an AC voltage is applied with a high voltage power source (not shown) into contact or in proximity, and discharging by a minute gap. The image carrier is charged. 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. The above-mentioned decomposition products, oxides, and air discharge products are generally hydrophilic or contain a hydrophilic group.
The image carrier protective agent contains an amphiphilic organic compound (B) having a hydrophilic part and a hydrophobic part in one molecule as a composition. Moreover, the hydrophobic organic compound (A) is also included as one composition. Therefore, the surface of the image bearing member becomes hydrophilic due to electrical stress, whereby the amphiphilic organic compound (B) is adsorbed to make the surface hydrophobic and the surrounding hydrophobic organic compound (A ) Prevents an electrical stress from being directly applied to the surface of the image carrier.
Instead, a part of the image carrier protecting agent is deteriorated by exposure to electrical stress and becomes partially hydrophilic, but is present in excess, an amphiphilic organic compound (B) having an appropriate HLB value. ) Together with the reverse micelle and dispersed in the hydrophobic organic compound (A), so that both the image carrier protective effect by the image carrier protective layer and the removability of the deteriorated image carrier protective agent are compatible Is possible.

  The deteriorated image carrier protective agent is removed by the cleaning mechanism together with other components such as toner remaining on the image carrier by a normal cleaning mechanism. The cleaning mechanism may be combined with the protective layer forming mechanism described above, but the function of removing the image carrier surface residue and the function of forming the protective layer may differ in the rubbing state of an appropriate member. For this reason, it is preferable to provide a cleaning mechanism 4 including a cleaning member 41, a cleaning pressing mechanism 42, and the like on the upstream side of the image carrier protecting agent supply unit as shown in FIG.

  The material of the blade used for the protective layer forming mechanism is not particularly limited. For example, elastic materials such as urethane rubber, hydrin rubber, silicone rubber, and fluorine rubber, which are generally known as cleaning blade materials, may be used alone or in combination. Can be used. Further, these rubber blades may be coated or impregnated with a low friction coefficient material at the contact point with the image carrier. Further, in order to adjust the hardness of the elastic body, fillers represented by other organic fillers and inorganic fillers may be dispersed.

These blades are fixed to the blade support by an arbitrary method such as adhesion or fusion so that the tip can be pressed against the surface of the image carrier. The blade thickness cannot be uniquely defined in consideration of the force applied by pressing, but can be preferably used if it is about 0.5 to 5 mm, and more preferably about 1 to 3 mm.
Similarly, the length of the cleaning blade that protrudes from the support and can bend, that is, the so-called free length, is not uniquely defined in consideration of the force applied by pressing, but is generally 1 to 15 mm. If it is a grade, it can use preferably, and if it is about 2-10 mm, it can use still more preferably.

As another configuration of the protective layer forming blade member, a layer of resin, rubber, elastomer or the like is coated on the surface of an elastic metal blade such as a spring plate, if necessary, via a coupling agent, a primer component, etc. It may be formed by a method, heat-cured or the like if necessary, and further subjected to surface polishing if necessary.
The thickness of the elastic metal blade is preferably about 0.05 to 3 mm, and more preferably about 0.1 to 1 mm.
Moreover, in an elastic metal blade, in order to suppress the twist of a blade, you may perform processes, such as a bending process, in the direction substantially parallel to a spindle after attachment.
As a material for forming the surface layer, fluorine resin such as PFA, PTFE, FEP, PVdF, silicone elastomer such as fluorine rubber, methylphenyl silicone elastomer, and the like can be used together with a filler, if necessary. It is not limited to this.

Further, the force for pressing the image carrier by the protective layer forming mechanism is sufficient to spread the image carrier protective agent to become a protective layer or a protective film, and the linear pressure is 5 gf / cm or more and 80 gf / cm or less. It is preferable that it is 10 gf / cm or more and 60 gf / cm or less.
A brush-like member is preferably used as the protective agent supply member. In this case, the brush fiber is preferably flexible in order to suppress mechanical stress on the surface of the image carrier.

As a specific material of the flexible brush fiber, one or more kinds can be selected and used from generally known materials. Specifically, polyolefin resins (for example, polyethylene, polypropylene); polyvinyl and polyvinylidene resins (for example, polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and Polyvinyl chloride); vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; styrene-butadiene resin; fluorine resin (for example, polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene); Polyester; Nylon; Acrylic; Rayon; Polyurethane; Polycarbonate; Phenol resin; Amino resin (eg urea-formaldehyde resin, mela Down resins, benzoguanamine resins, urea resins, polyamide resins); Among such, it may be a resin having flexibility.
Also, in order to adjust the degree of bending, diene rubber, styrene-butadiene rubber (SBR), ethylene propylene rubber, isoprene rubber, nitrile rubber, urethane rubber, silicone rubber, hydrin rubber, norbornene rubber, etc. are used in combination. Also good.

The support for the protective agent supply member includes a fixed mold and a rotatable roll. As the roll-shaped supply member, for example, there is a roll brush in which a tape having brush fibers piled is wound around a metal core 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 × 10 per square meter). ⁸ ) are preferably used.
As the protective agent supply member, it is preferable to use a material having a high brush density as much as possible from the viewpoint of uniformity of supply and its stability, and it is also possible to make one fiber from several to several hundred fine fibers. preferable. For example, bundling 50 fine fibers of 6.7 decitex (6 denier), such as 333 decitex = 6.7 decitex × 50 filament (300 denier = 6 denier × 50 filament), and implanting as one fiber Is also possible.

  Moreover, you may provide a coating layer in the brush surface for the purpose of stabilizing the surface shape of a brush, environmental stability, etc. 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, and these are not limited as long as the material can maintain flexibility. Polyolefin resins such as polyethylene, polypropylene, chlorinated polyethylene, chlorosulfonated polyethylene, etc .; polystyrene, acrylic (for example, polymethyl methacrylate), polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, Polyvinyl and polyvinylidene resins such as polyvinyl carbazole, polyvinyl ether, and polybiliketones; vinyl chloride-vinyl acetate copolymers; silicone resins composed of organosiloxane bonds or modified products thereof (eg, alkyd resins) Modified products by polyester resin, epoxy resin, polyurethane, etc.); Fluororesin such as perfluoroalkyl ether, polyfluorovinyl, polyfluorovinylidene, polychlorotrifluoroethylene; polyamide; polyester; polyurethane; polycarbonate; urea-formaldehyde resin, etc. Amino resins; epoxy resins, composite resins of these, and the like.

Figure 2 is a cross-sectional view for explaining the outline of the process cartridge configuration example using the protective layer forming device according to the present invention.
In the figure, reference numeral 5 denotes a developing device, 6 denotes a transfer roller, 7 denotes a transfer medium, 51 denotes a developing roller, 52 and 53 denote a toner transport mechanism, and 500 denotes a process cartridge. Other symbols are the same as those in FIG.
In a process cartridge unit (referred to as a PCU), a protective layer forming device 2 disposed opposite to the photosensitive drum 1 as an image carrier includes an image carrier protective agent 21, a protective agent supply member 22, and a pressing force application. It is mainly composed of a mechanism 23, a protective layer forming mechanism 24, and the like.
Further, the image carrier 1 has a surface on which the image carrier protective agent and the toner component partially deteriorated after the transfer process remain, but the surface residue is cleaned and cleaned by the cleaning member 41.
In FIG. 2, the cleaning member is abutted at an angle similar to a so-called counter type (leading type).

The image carrier protective agent 21 is supplied from the protective agent supply member 22 to the surface of the image carrier from which the residual toner on the surface and the deteriorated image carrier protective agent have been removed by the cleaning mechanism. A film-like protective layer is formed. At this time, the image carrier protective agent used in the present invention has a better adsorptivity to the portion of the surface of the image carrier that is highly hydrophilic due to electrical stress. Even if electrical stress is applied and the surface of the image carrier starts to deteriorate partially, the image carrier itself can be prevented from progressing by adsorption of the protective agent.
The image bearing member on which the protective layer is formed is charged, and then an electrostatic latent image is formed by exposure with a laser or the like, developed by the developing device 5 to be visualized, and transferred by the transfer roller 6 outside the process cartridge. Transferred to the transfer medium 7.

Figure 3 is a sectional view showing an example of an image forming apparatus including the protective layer forming device according to the present invention.
In the figure, reference numeral 8 denotes a latent image forming apparatus, 60 denotes an intermediate transfer medium, 100 denotes an image forming apparatus, and 200 denotes a paper feeding mechanism.
Around the drum-shaped image carrier 1, a protective layer forming device 2, a charging device 3, a latent image forming device 8, a developing device 5, a transfer device 6, and a cleaning device 4 are arranged. Done.
A series of processes for image formation will be described using a negative-positive process.
An image carrier 1 typified by a photoreceptor (OPC) having an organic photoconductive layer is neutralized by a neutralizing lamp (not shown) or the like, and is uniformly negatively charged by a charging device 3 having a charging member.

When the image carrier is charged by the charging device, an appropriate voltage or voltage suitable for charging the image carrier 1 to a desired potential from a voltage application mechanism (not shown) to the charging member. A charging voltage in which an AC voltage is superimposed on this is applied.
The charged image carrier 1 forms a latent image with laser light irradiated by a latent image forming device 8 such as a laser optical system (the absolute value of the exposed portion potential is lower than the absolute value of the non-exposed portion potential). ) Is performed.
Laser light is emitted from a semiconductor laser, and the surface of the image carrier 1 is scanned in the direction of the rotation axis of the image carrier 1 by a polygonal polygonal mirror (polygon) that rotates at high speed.
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 of an appropriate magnitude between the exposed portion and the non-exposed portion of the image carrier 1 or an AC voltage superimposed on the developing sleeve from a voltage application mechanism (not shown) is developed. A bias is applied.

The toner image formed on the image carrier 1 corresponding to each color is transferred onto the intermediate transfer medium 60 by the transfer device 6 and is transferred onto the transfer medium such as paper fed from the paper feeding mechanism 200. The image is transferred.
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 medium 60 is separated from the image carrier 1 to obtain a transfer image.
Further, the toner particles remaining on the image carrier are collected by the cleaning member 41 into the toner collection chamber in the cleaning device 4.
As the image forming apparatus 100, a plurality of the above-described developing devices are used, and a plurality of toner images having different colors sequentially generated by the plurality of developing devices are sequentially transferred onto a transfer material, and then sent to a fixing mechanism. Even in a device that fixes toner by heat or the like, or after sequentially transferring a plurality of similarly created toner images to an intermediate transfer medium in order, and then transferring them all at once to a transfer medium such as paper Similarly, a fixing device may be used.

The charging device 3 described above is preferably a charging device disposed in contact with or close to the surface of the image carrier, whereby a corona discharge device called a corotron or a scorotron using a discharge wire. In comparison with the above, the amount of ozone generated during charging can be greatly suppressed.
However, in the charging device that charges the charging member in contact with or close to the surface of the image carrier, as described above, since the discharge is performed in the region near the surface of the image carrier, the electrical stress on the image carrier is large. It tends to be. By using the protective layer forming apparatus using the image carrier protecting agent of the present invention, the image carrier can be maintained for a long time without deteriorating. It can be greatly suppressed and stable image quality can be ensured.
As the image forming apparatus 100, an apparatus in which the photosensitive member 1 and its peripheral mechanism are replaced with the PCU shown in FIG. 2 can be used.

Next, a photoconductor preferably used in the present invention will be described.
In the photoreceptor used in the image forming apparatus of the present invention, a photosensitive layer is provided on a conductive support. The photosensitive layer is composed of 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 provided on the charge transport layer. There is a reverse layer type. In addition, a protective layer can be provided on the photosensitive layer in order to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, and the like of the photoreceptor. An undercoat layer may be provided between the photosensitive layer and the conductive support. In addition, an appropriate amount of a plasticizer, an antioxidant, a leveling agent and the like can be added to each layer as necessary.

As the conductive support of the photoreceptor, a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation A metal oxide such as indium is deposited or sputtered to form a film or cylindrical plastic, paper coated, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc. After forming the tube into a drum shape, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. A drum-shaped support having a diameter of 20 to 150 mm, preferably 24 to 100 mm, and more preferably 28 to 70 mm can be used. If the diameter of the drum-shaped support is 20 mm or less, it is physically difficult to arrange the charging, exposure, development, transfer, and cleaning steps around the drum. If the diameter of the drum-shaped support is 150 mm or more, image formation is performed. The apparatus becomes undesirably large. In particular, when the image forming apparatus is a tandem type, it is necessary to mount a plurality of photoconductors, and thus the diameter is preferably 70 mm or less, and preferably 60 mm or less. Also, known endless nickel belts and endless stainless steel belts can be used as the conductive support.

  Examples of the undercoat layer of the photoreceptor include a resin or a white pigment and a resin as a main component, and a metal oxide film obtained by chemically or electrochemically oxidizing the surface of a conductive substrate. What has resin as a main component is preferable. Examples of the white pigment include metal oxides such as titanium oxide, aluminum oxide, zirconium oxide, and zinc oxide. Among them, it is most preferable to contain titanium oxide that is excellent in preventing charge injection from the conductive substrate. As the resin used for the undercoat layer, thermoplastic resins such as polyamide, polyvinyl alcohol, casein, and methyl cellulose, thermosetting resins such as acrylic, phenol, melamine, alkyd, unsaturated polyester, and epoxy, one or various kinds of these Mixtures can be exemplified.

  Examples of the charge generating substance of the photoreceptor include azo pigments such as monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine Organic dyes, styryl dyes, pyrylium dyes, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indanthrone pigments, squarylium pigments, phthalocyanine pigments, etc. Inorganic materials such as pigments and dyes, selenium, selenium-arsenic, selenium-tellurium, cadmium sulfide, zinc oxide, titanium oxide, and amorphous silicon can be used, and charge generating substances can be used alone or in combination. be able to. The undercoat layer may be a single layer or a plurality of layers.

  Examples of the charge transport material of the photoreceptor 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 compounds. , An oxazole compound, an oxadiazole compound, a thiazole compound, an imidazole compound, a triphenylamine derivative, a phenylenediamine derivative, an aminostilbene derivative, a triphenylmethane derivative, and the like, or a mixture thereof can be used.

  The binder resin used to form the photosensitive layer of the charge generation layer and the charge transport layer is electrically insulating and is a known thermoplastic resin, thermosetting resin, photocurable resin, and photoconductive material. Suitable binder resins include, for example, 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, thermoplastic resin such as polysulfone, polyethersulfone, ABS resin, phenol resin , Epoxy resin, urethane resin, melamine resin, isocyanate resin, alkyd resin A silicone resin, a thermosetting resin such as a thermosetting acrylic resin, a photoconductive resin such as polyvinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, and the like, may include one kind of binder resin or a mixture of various kinds of binder resins. In particular, it is not limited to these.

As antioxidant, the following are used, for example.
<Monophenol compound>
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, 3-t-butyl-4-hydroxynisol and the like.
<Bisphenol compounds>
2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′-thiobis- ( 3-methyl-6-t-butylphenol), 4,4′-butylidenebis- (3-methyl-6-t-butylphenol) and the like.

<High molecular phenolic compound>
1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4 ′) -Hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocophenols and the like.
<Paraphenylenediamines>
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

<Hydroquinones>
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
<Organic sulfur compounds>
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.
<Organic phosphorus compounds>
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

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 weight with respect to 100 parts by weight of the binder resin. Is appropriate.
A leveling agent may be added to the charge transport layer. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 100 parts by weight of the binder resin. 0 to 1 part by weight is suitable.

  As described above, the surface layer is provided to improve the mechanical strength, abrasion resistance, gas resistance, cleaning property, etc. of the photoreceptor. Examples of the surface layer include a polymer having a mechanical strength higher than that of the photosensitive layer and a polymer in which an inorganic filler is dispersed. The polymer used for the surface layer may be either a thermoplastic polymer or a thermosetting polymer, but the thermosetting polymer has a high mechanical strength and does not wear due to friction with the cleaning blade. It is very preferable because of its extremely high ability to suppress. If the surface layer has a thin film thickness, there is no problem even if it does not have the charge transport capability. However, 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 remains. Since the potential rise is likely to occur, it is preferable to use the above-mentioned charge transporting substance in the surface layer or to use a polymer having a charge transporting capability for the protective layer. When the surface layer is provided, the mechanical strength of the photosensitive layer and the surface layer is generally greatly different, and therefore the protective layer is worn away due to friction with the cleaning blade. It is important that the surface layer has a sufficient film thickness, and is 0.1 to 12 μm, preferably 1 to 10 μm, more preferably 2 to 8 μm. If the film thickness of the surface layer is 0.1 μm or less, it is not preferable because it is too thin and easily disappears due to friction with the cleaning blade, and wear of the photosensitive layer proceeds from the disappeared portion. When the film thickness of the surface layer is 12 μm or more, the sensitivity is lowered, the potential after exposure is increased, and the residual potential is easily increased. In particular, when a polymer having charge transport capability is used, the cost of the polymer having charge transport capability is high. This is not preferable.

  The polymer used for the surface layer is preferably a material that is transparent to the writing light during image formation and has excellent insulation, mechanical strength, and adhesiveness. 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, polymethyl Examples include resins such as bentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride, and epoxy resin. . These polymers may be thermoplastic polymers, 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 curable polymer, the mechanical strength of the surface layer is increased, and wear due to friction with the cleaning blade can be greatly reduced.

As described above, it is preferable that the surface layer has a charge transport capability. In order to provide the surface layer with a charge transport capability, a polymer used for the surface layer and the above-described charge transport material are mixed. A method of using a polymer having a charge transporting capability for the surface layer is conceivable, and the latter method is preferable because it can obtain a photoconductor with high sensitivity and little increase in potential after exposure and little increase in residual potential.
Examples of the polymer having a charge transport layer ability include a group having a charge transport ability in the polymer; Chemical Formula (2).

In the above formula, Ar ₁ represents a substituted or unsubstituted arylene group. Ar ₂ and Ar ₃ represent a substituted or unsubstituted aryl group, and may be the same or different.
The group having the charge transporting ability is preferably added to a side chain of a polymer having high mechanical strength such as a polycarbonate resin or an acrylic resin, and the monomer can be easily produced, and the acrylic having excellent coatability and curability. It is preferable to use a resin.

An acrylic resin having a charge transporting ability can form a surface layer having high mechanical strength, excellent transparency, and high charge transporting ability by polymerizing an unsaturated carboxylic acid having a group of the chemical formula (2). The acrylic resin forms a crosslinked structure by mixing a polyfunctional unsaturated carboxylic acid, preferably a tri- or higher functional unsaturated carboxylic acid, with the unsaturated carboxylic acid having a monofunctional chemical formula (2) group. It becomes a thermosetting polymer, and the mechanical strength of the surface layer becomes extremely high. Although the group of the chemical formula (2) may be added to the polyfunctional unsaturated carboxylic acid, since the production cost of the monomer becomes high, the polyfunctional unsaturated carboxylic acid has a group of the chemical formula (2). Usually, it is preferable to use a photocurable polyfunctional monomer.
Examples of the monofunctional unsaturated carboxylic acid having a group of chemical formula (2) include chemical formula (3) and chemical formula (4).

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

  The proportion of the polyfunctional unsaturated carboxylic acid is 5 to 75% by weight, preferably 10 to 70% by weight, more preferably 20 to 60% by weight, based on the entire surface layer. When the ratio of the polyfunctional unsaturated carboxylic acid is 5% by weight or less, the mechanical strength of the surface layer is insufficient, and when it is 75% or more, cracks are likely to occur when a strong force is applied to the surface layer, resulting in sensitivity deterioration. Is also not preferable because it is likely to occur.

When an acrylic resin is used for the surface layer, the surface layer is formed by applying the unsaturated carboxylic acid to the photoreceptor and then irradiating with an electron beam or actinic rays such as ultraviolet rays to cause radical polymerization. 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.
In the surface layer, fine particles of metal or metal oxide can be dispersed in order to increase the mechanical strength of the surface layer. Examples of the metal oxide include titanium oxide, tin oxide, potassium titanate, TiO, TiN, zinc oxide, indium oxide, and antimony oxide. In addition, fluorine resins such as polytetrafluoroethylene, silicone resins, and those obtained by dispersing inorganic materials in these resins can be added for the purpose of improving wear resistance.

The image carrier according to the present invention is used when performing image formation by a so-called intermediate transfer method in which a toner image formed on a photoreceptor is primarily transferred to perform color superposition and further transferred to a transfer medium. An intermediate transfer medium may be used.
As the intermediate transfer medium, a medium having a volume resistance of 10 ⁵ to 10 ¹¹ Ω · cm 2 is preferable. If the volume resistivity is below 10 ⁵ Omega · cm, when the transfer of the toner image is performed onto the intermediate transfer medium from the photosensitive member, there is so-called transfer dust which the toner image with the discharge is disturbed occurs, 10 ¹¹ If it exceeds Ω · cm 2, after the toner image is transferred from the intermediate transfer medium to a transfer medium such as paper, the counter charge of the toner image remains on the intermediate transfer medium and appears as an afterimage on the next image. is there.
As an intermediate transfer medium, for example, a metal oxide such as tin oxide or indium oxide, or conductive particles such as carbon black or a conductive polymer, alone or in combination, kneaded with a thermoplastic resin, and then extruded into a belt shape Alternatively, a cylindrical plastic can be used. In addition to this, 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 medium on an endless belt. You can also.
When providing a surface layer on the intermediate transfer medium, among the surface layer materials used for the above-mentioned photoreceptor surface layer, the composition excluding the charge transport material is appropriately adjusted in combination with a conductive substance, Can be used.

Next, the toner suitably used in the present invention will be described.
First, the toner used in the present invention preferably has an average circularity of 0.93 to 1.00. In the present invention, the value obtained from Equation 1 below is defined as the circularity. This circularity is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is a perfect sphere, and the circularity becomes smaller as the surface shape becomes more complicated.
Circularity SR = perimeter of a circle having the same area as the particle projection area / perimeter of the particle projection image
When the average circularity is in the range of 0.93 to 1.00, the surface of the toner particles is smooth, and the contact area between the toner particles and between the toner particles and the photosensitive member is small, so that the transferability is excellent.
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.
Since there are no angular toner particles in the toner that forms the dots, when the pressure is brought into contact with the transfer medium during the transfer, the pressure is uniformly applied to the entire toner that forms the dots, and the transfer is not easily lost.
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.

Next, a method for measuring the circularity will be described.
The circularity can be measured using a flow type particle image analyzer FPIA-1000 manufactured by Toa Medical Electronics.
As a specific measurement method, 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance. About 0.1 to 0.5 g. 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.

In the present invention, the weight average diameter D4 of the toner is preferably 3 to 10 μm.
In this range, since the toner particles have a sufficiently small particle size with respect to the minute latent image dots, the dot reproducibility is excellent.
When the weight average diameter D4 is less than 3 μm, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning properties tend to occur.
When the weight average diameter D4 exceeds 10 μm, it is difficult to suppress scattering of characters and lines.

In the toner according to the present invention , the ratio of the weight average diameter D4 to the number average diameter D1 (D4 / D1) is preferably 1.00 to 1.40. The closer the value of (D4 / D1) is to 1, the sharper the particle size distribution of the toner.
Therefore, when (D4 / D1) is in the range of 1.00 to 1.40, the selective development due to the toner particle size does not occur, and the stability of the image quality is excellent.
Since the toner particle size distribution is sharp, the triboelectric charge amount distribution is also sharp, and fogging is suppressed.
When the toner particle diameter is uniform, the latent image dots are developed so as to be arranged in a precise and orderly manner, so that the dot reproducibility is excellent.

Next, a method for measuring the particle size distribution of toner particles will be described.
Examples of the measuring device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). The measurement method is described below.
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 a solution prepared by preparing a 1% NaCl aqueous solution using primary sodium chloride. For example, ISOTON-II (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 weight average diameter D4 and the number average 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.

  In addition, as such a substantially spherical toner, a toner composition containing a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent in an aqueous medium in the presence of fine resin particles. A toner that undergoes crosslinking and / or elongation reaction is preferred. The toner manufactured by this reaction can reduce the hot offset by curing the surface of the toner, and it can be suppressed that the fixing device becomes dirty and appears on the image.

Examples of the prepolymer comprising a modified polyester resin that can be used for toner production include a polyester prepolymer (A) having an isocyanate group, and examples of the compound that extends or crosslinks with the prepolymer include amines (B). Can be mentioned.
Examples of the polyester prepolymer (A) having an isocyanate group include a product obtained by further reacting a polyester having an active hydrogen group with a polyisocyanate (3), which is a polycondensate of polyol (1) and polycarboxylic acid (2). Can be 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 preferred.

  Examples of the polyol (1) include a diol (1-1) and a tri- or higher valent polyol (1-2). (1-1) alone or (1-1) and a small amount of (1-2) Mixtures are preferred. Diol (1-1) includes 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 above alicyclic diol; Alkylene oxide phenol compound (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyol (1-2) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

Examples of the polycarboxylic acid (2) include dicarboxylic acid (2-1) and trivalent or higher polycarboxylic acid (2-2). (2-1) alone and (2-1) with a small amount of ( The mixture of 2-2) is preferred. Dicarboxylic acid (2-1) includes alkylene dicarboxylic acid (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acid (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid) , Naphthalenedicarboxylic acid, etc.). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polycarboxylic acid (2-2) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, and the like). In addition, as polycarboxylic acid (2), you may make it react with polyol (1) using the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned thing.
The ratio of the polyol (1) to the polycarboxylic acid (2) is usually 2/1 to 1/1, preferably 1. as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 5/1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (3) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates such as phenol derivatives, oximes, caprolactam And a combination of two or more of these.

The ratio of the polyisocyanate (3) is usually 5/1 to 1/1, preferably 4 /, as the equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content in the modified polyester will be low, and the hot offset resistance will deteriorate. The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by weight, preferably 1 to 30% by weight, more preferably 2 to 20% by weight. It is. If it is less than 0.5% by weight, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by weight, the low-temperature fixability deteriorates.
The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1-B5 blocked (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. Examples of the B1 to B5 amino group blocked (B6) include ketimine compounds and oxazoline compounds obtained from the B1 to B5 amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). 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.), and those obtained by blocking them (ketimine compounds).
The ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 1/2 to 2/1, preferably 1 / 1.5 to 1.5 / 1, more preferably 1.1 / 1.2 to 2/1. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester (i) becomes low, and the hot offset resistance deteriorates. In the present invention, the polyester (i) modified with a urea bond may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

These reactions, the modified polyester for use in the toner of the present invention, among others the urea-modified polyester (i) can be produced. These urea-modified polyesters (i) are produced by a one-shot method or a prepolymer method. The weight average molecular weight of the urea-modified polyester (i) is usually 10,000 or more, preferably 20,000 to 10,000,000, more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester is not particularly limited when the unmodified polyester (ii) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. (I) When used alone, the number average molecular weight is usually 20000 or less, preferably 1000 to 10000, and more preferably 2000 to 8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  Moreover, in this invention, not only polyester (i) modified | denatured with the said urea bond but polyester (ii) which is not modified | denatured with this (i) can also be contained as a binder resin component. By using (ii) in combination, the low-temperature fixability and the gloss when used in a full-color device are improved, which is preferable to the single use. Examples of (ii) include the same polycondensates of polyol (1) and polycarboxylic acid (2) as in the polyester component (i) above, and preferred ones are also the same as (i). Further, (ii) is not limited to unmodified polyester, but may be modified with a chemical bond other than a urea bond, for example, may be modified with a urethane bond. It is preferable that (i) and (ii) are at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component (i) and (ii) preferably have similar compositions. In the case of containing (ii), the weight ratio of (i) to (ii) is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, Particularly preferred is 7/93 to 20/80. If the weight ratio of (i) is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight of (ii) is usually 1000-30000, preferably 1500-10000, more preferably 2000-8000. If it is less than 1000, heat-resistant storage stability will deteriorate, and if it exceeds 30000, low-temperature fixability will deteriorate. The hydroxyl value of (ii) is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If it is less than 5, it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. The acid value of (ii) is usually 1-30, preferably 5-20. By having an acid value, it tends to be negatively charged.

In the present invention, the glass transition point (Tg) of the binder resin is usually 50 to 70 ° C., preferably 55 to 65 ° C. If it is less than 50 ° C., the blocking of the toner during high temperature storage deteriorates, and if it exceeds 70 ° C., the low temperature fixability becomes insufficient. Due to the coexistence of the urea-modified polyester resin, the dry toner of the present invention tends to have good heat-resistant 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 10000 dyne / cm ² is obtained at a measurement frequency of 20 Hz is usually 100 ° C. or higher, preferably 110 to 200 ° C. If it is less than 100 ° C., the resistance to hot offset deteriorates. As the viscosity of the binder resin, the temperature (Tη) at 1000 poise at a measurement frequency of 20 Hz is usually 180 ° C. or less, preferably 90 to 160 ° C. If it 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, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

  The binder resin can be produced by the following method. The polyol (1) and the polycarboxylic acid (2) are heated to 150 to 280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and the generated water is distilled off as necessary. Thus, a polyester having a hydroxyl group is obtained. Next, this is reacted with polyisocyanate (3) at 40 to 140 ° C. to obtain a prepolymer (A) having an isocyanate group. 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 aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to the isocyanate (3), such as tetrahydrofuran (such as tetrahydrofuran). When polyester (ii) not modified with urea bond is used in combination, (ii) is produced in the same manner as polyester having a hydroxyl group, and this is dissolved in the solution after completion of the reaction of (i) and mixed. To do.

The toner used in the present invention can be generally produced by the following method, but is not limited thereto.
The aqueous medium used in the present invention may be water alone, or 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 (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  The toner particles 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 (i) produced in advance. good. As a method for stably forming a dispersion comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium, a toner raw material comprising urea-modified polyester (i) or prepolymer (A) in an aqueous medium is used. And a method of dispersing by shearing force. The prepolymer (A) and other toner compositions (hereinafter referred to as toner raw materials), a colorant masterbatch, a release agent, a charge control agent, an unmodified polyester resin, etc. are dispersed in an aqueous medium. It may be mixed at the time of formation, 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 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, but after the particles are formed. It may be added. For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and 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 size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, 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. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion made of urea-modified polyester (i) or prepolymer (A) has a low viscosity and is easy to disperse.

The amount of the aqueous medium used relative to 100 parts of the toner composition containing the urea-modified polyester (i) and the prepolymer (A) is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, 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.
In the step of synthesizing the urea-modified polyester (i) from the prepolymer (A), the amine (B) may be added and reacted before the toner 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.

  Anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates and phosphates, alkylamines as dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed in a liquid containing water Amine salts such as salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, imidazoline, alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, etc. Nonionic surfactants such as quaternary ammonium salt type cationic surfactants, fatty acid amide derivatives, polyhydric alcohol derivatives, such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl N, amphoteric surfactants such as N- dimethyl ammonium betaine and the like.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred examples of the anionic surfactant having a fluoroalkyl group include fluoroalkylcarboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6 -C11) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) ) Carboxylic acids and metal salts, perfluoroalkyl carboxylic acids (C7 to C13) and their metal salts, perfluoroalkyl (C4 to C12) sulfonic acids and their metal salts, perfluorooctane sulfonic acid diethanolamide, N -Propyl-N- (2hydroxy Til) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphoric acid Examples include esters.

  Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (Daikin Kogyo Co., Ltd.), Mega-Fac F-l0, F-l20, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.), Xtop EF-102 , 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fagento F-100, F150 (manufactured by Neos).

Cationic surfactants include aliphatic primary, secondary or secondary amine acids having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts, benzalkonium Salt, benzethonium chloride, pyridinium salt, imidazolinium salt, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Kogyo Co., Ltd.), Mega Fax F-150, F-824 (manufactured by Dainippon Ink, Inc.), Xtop EF-132 (manufactured by Tochem Products), and Fategent F-300 (manufactured by Neos).
Tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite, and the like can also be used as a water-insoluble inorganic compound dispersant.

  The dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloroacrylate 2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N -Methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc., or esters of compounds containing vinyl alcohol and carboxyl groups, such as Vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethylene imine, etc. Homopolymers or copolymers such as those having a nitrogen atom or a heterocyclic ring thereof, polyoxyethylene, polyoxypropylene, Oxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonylphenyl Polyoxyethylenes such as esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

If an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by dissolving the calcium phosphate salt with an acid such as hydrochloric acid and then washing with water. To do. It can also be removed by operations such as enzymatic degradation.
When a dispersant is used, the dispersant may remain on the surface of the toner particles, but it is preferable from the charged surface of the toner that the dispersant is washed and removed after the elongation and / or crosslinking reaction.

  Furthermore, in order to lower the viscosity of the toner composition, a solvent in which the urea-modified polyester (i) or the prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile from the viewpoint of easy removal. 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, Methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride are preferred, and aromatic solvents such as toluene and xylene are more preferred. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. 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 of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. is there. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. 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. Alternatively, the emulsified dispersion can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner fine particles, and the aqueous dispersant can be removed by evaporation together. . 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. Sufficient quality can be obtained with a short treatment such as spray dryer, belt dryer or 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 classification 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. Of course, the classification operation may be performed after obtaining the powder as a powder after drying. 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, fine particles or coarse particles may be wet.
The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above.

By mixing the resulting dried toner powder with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or by giving mechanical impact force to the mixed powder By immobilizing and fusing on the surface, it is possible to prevent the detachment of the foreign particles from the surface of the resulting composite particle.
Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) is modified to reduce the grinding air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron system (Made by Kawasaki Heavy Industries, Ltd.), automatic mortar and the like.

As the colorant used in the toner, pigments and dyes that have been 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, magnetic components such as iron oxides such as ferrite, magnetite and maghemite, metals such as iron, cobalt and nickel, or alloys of these with other metals. May be contained alone or in combination in the toner particles. Moreover, these components can also be used / used together as a colorant component.

The number average diameter of the colorant in the toner used in the present invention is desirably 0.5 μm or less, preferably 0.4 μm or less, more preferably 0.3 μm or less.
When the number average diameter of the colorant in the toner is larger than 0.5 μm, the dispersibility of the pigment does not reach a sufficient level, and preferable transparency may not be obtained.
A 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 light reflection and absorption characteristics. Therefore, the colorant particles 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 larger than 0.5 μm, the transmission of incident light is hindered or scattered, and the brightness and vividness of the projected image of the OHP sheet tend to decrease. There is.
Further, if there are many colorants having a particle size larger than 0.5 μm, the colorant is detached from the surface of the toner particles, and various problems such as fogging, drum contamination, and poor cleaning are liable to occur. In particular, the colorant having a particle size larger than 0.7 μm is preferably 10% by number or less, more preferably 5% by number or less of the total colorant.
By adding a wetting liquid in advance with a part or all of the binder resin and kneading the colorant in advance, the binder resin and the colorant are initially sufficiently adhered, and the subsequent toner Colorant dispersion in the toner particles in the production process is more effectively performed, and the dispersed particle diameter of the colorant is reduced, so that 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.
As the wetting liquid, a general one can be used in consideration of the solubility of the binder resin and the wettability with the colorant. In particular, organic solvents 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 more 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.

In addition, as long as the configuration of the present invention is adopted, a release agent represented by wax can be contained in the toner together with the binder resin and the colorant.
Known release agents can be used, such as polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sasol wax, etc.); carbonyl group-containing wax, etc. .
Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyalkanoic acid esters (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18. -Octadecanediol distearate, etc.); polyalkanol esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyalkanoic acid amides (ethylene diamine dibehenyl amide, etc.); polyalkylamides (trimellitic acid tristearyl amide, etc.) And dialkyl ketones (such as distearyl ketone).

  Among these carbonyl group-containing waxes, polyalkanoic acid esters are preferred. The melting point of these release agents is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point of less than 40 ° C. has an adverse effect on heat resistant storage stability, and a wax having a melting point of more than 160 ° C. tends to cause a cold offset when fixing at a low temperature. Further, the melt viscosity of the wax is preferably 5 to 1000 cps, more preferably 10 to 100 cps as a measured value at a temperature 20 ° C. higher than the melting point. Waxes exceeding 1000 cps have poor effects for improving hot offset resistance and low-temperature fixability. The content of the wax in the toner is usually 0 to 40% by weight, preferably 3 to 30% by weight.

In order to accelerate the toner charge amount and its rise, a charge control agent may be contained in the toner as necessary. Here, since a color change occurs when a colored material is used as the charge control agent, a material that is colorless and close to white is preferable.
Any known charge control agent can be used. Examples include triphenylmethane dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkyls. Amide, phosphorus simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like. Specifically, Bontron P-51 of a quaternary ammonium salt, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex, E-89 of a phenol condensate (above, Orient Chemical Co., Ltd.) Manufactured), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), copy charge PSY VP2038 of quaternary ammonium salt, copy blue PR of triphenylmethane derivative, Quaternary ammonium salt copy charge NEG VP2036, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, boron complex LR-147 (manufactured by Nippon Carlit), quinacridone, azo pigment, other sulfonic acid groups Of polymers with functional groups such as carboxylic groups and quaternary ammonium salts Thing, and the like.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch and resin, or may be added when directly dissolving and dispersing in an organic solvent, or may be fixed on the toner surface after preparation of toner particles. Also good.

When the toner composition is dispersed in the aqueous medium during the toner production process, resin fine particles for mainly stabilizing the dispersion may be added.
The resin fine particles used may be any resin that 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, Examples thereof include polyamide resin, polyimide resin, silicon resin, phenol resin, melamine resin, urea resin, aniline resin, ionomer resin, and polycarbonate resin. As the resin fine particles, two or more of the above resins may be used in combination. Of these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, and combinations thereof are preferred because an aqueous dispersion of fine spherical resin particles is easily obtained.
The vinyl resin is a polymer obtained by homopolymerization or copolymerization of a vinyl monomer, such as a styrene- (meth) acrylate resin, a styrene-butadiene copolymer, a (meth) acrylic acid-acrylate polymer, Examples include, but are not limited to, styrene-acrylonitrile copolymers, styrene-maleic anhydride copolymers, styrene- (meth) acrylic acid copolymers, and the like.

Further, inorganic fine particles can be preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles.
The primary particle diameter of the inorganic fine particles is preferably 0.005 μm to 2 μm, and particularly preferably 0.005 μm to 0.5 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight of the toner, and particularly preferably 0.01 to 2.0% by weight. Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

Other polymer fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization and dispersion polymerization, methacrylic acid ester and acrylic acid ester copolymer, polycondensation system such as silicone, benzoguanamine and nylon, and thermosetting resin Examples include polymer particles.
Such a fluidizing agent can be surface-treated to increase hydrophobicity and prevent deterioration of flow characteristics and charging characteristics even under high humidity. For example, silane coupling agents, silylating agents, silane coupling agents having an alkyl fluoride group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils and the like are preferable surface treatment agents. .
Examples of the cleaning property improver for removing the developer after transfer remaining on the photoreceptor or the primary transfer medium include, for example, zinc stearate, calcium stearate, fatty acid metal salts such as stearic acid, such as polymethyl methacrylate fine particles, polystyrene fine particles, etc. And polymer fine particles produced by soap-free emulsion polymerization. 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 these toners, a high-quality toner image having excellent development stability can be formed as described above. However, the toner that is not transferred to the transfer medium or intermediate transfer medium by the transfer device and remains on the image carrier is difficult to remove by the cleaning device due to its fineness and good rolling properties. May end up. In order to completely remove the toner from the image carrier, it is necessary to strongly press a toner removing member such as a cleaning blade against the image carrier. Such a load not only shortens the life of the image carrier and the cleaning device, but also uses extra energy.
When the load on the image carrier is reduced, the toner and the small-diameter carrier on the image carrier are not sufficiently removed, and these damage the surface of the image carrier when passing through the cleaning device. It becomes a factor which fluctuates performance.
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, particularly the presence of a low-resistance portion, and highly suppresses fluctuations in charging performance to the image carrier. Due to the configuration, when used in combination with the toner having the above configuration, an extremely high quality image can be stably obtained over a long period of time.
The image forming apparatus of the present invention can be applied not only to the use of the toner having a configuration suitable for obtaining a high quality image as described above, but also to an irregularly shaped toner by a pulverization method, thereby greatly extending the life of the apparatus. Needless to say, it will be extended.

As a material constituting such a pulverized toner, those usually used as an electrophotographic toner can be applied without particular limitation.
Examples of general binder resins used in the toner include homopolymers of styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene and the like; and styrene / p-chlorostyrene copolymers. Styrene / propylene copolymer, styrene / vinyl toluene copolymer, styrene / vinyl naphthalene copolymer, styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, Styrene / octyl acrylate copolymer, styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene / α-chloromethyl methacrylate copolymer, styrene / Acrylonitrile copolymer, styrene / vinyl methyl ketone copolymer Styrene 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 homopolymers and copolymers 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 an epoxy polymer, a terpene polymer, an aliphatic or alicyclic hydrocarbon resin, an aromatic petroleum resin, and the like. These can be used alone or in combination, but are not particularly limited thereto. Among these, at least one selected from styrene-acrylic copolymer resins, polyester resins, and polyol resins is more preferable from the viewpoint of electrical characteristics, cost, and the like. Furthermore, it is more preferable to use a polyester-based resin and / or a polyol-based resin as having good fixing characteristics.

For the above reasons, the same resin component as the binder resin of the toner contained in the coating layer of the charging member is the linear polyester resin composition, linear polyol resin composition, linear styrene acrylic resin composition. Or at least one of these cross-linked products can be preferably used.
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 above-mentioned external additive components may be appropriately added and mixed as necessary.
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example.

75 parts by weight of synthetic paraffin FT-115 (melting temperature 105 ° C., manufactured by Nippon Seiki) and 25 parts by weight of glyceryl monostearate (melting temperature 80 ° C.) are placed in a glass container with a lid, and the temperature is controlled at 140 ° C. It melted with stirring with a hot stirrer. In this melt, 30 parts by weight of polytetrafluoroethylene particles having a number average particle size of 0.3 μm were mixed and stirred while maintaining a temperature of 140 ° C.
The molten protective agent composition is poured into a mold, allowed to cool to 50 ° C. in a room temperature atmosphere, then reheated to 60 ° C. in a temperature-controlled thermostat, held at that temperature for 20 minutes, and then to room temperature. Allowed to cool.
The melting temperature of paraffin is defined as the endothermic peak temperature in the DSC spectrum measured to about 150 mg with a differential scanning calorimeter DSC-60 (manufactured by Shimadzu Corporation) at a heating rate of 6 ° C./min in a nitrogen gas atmosphere. did.
The produced protective agent bar was mounted on each of four color process cartridges (PCU) of imagio Neo C385 (tandem type color image forming apparatus, manufactured by Ricoh), and 10,000 sheets of images were formed. As the application brush of the process cartridge, a polyester electrostatic flocking brush having a bristle thickness of 9d was used, and the protective agent bar was pressed with a spring pressure of 4.9 N.
Even after 10,000 sheets of images were formed, no toner adhered to the protective agent bar, and high-quality images were seen for all colors.

<Comparative Example 1>
In Example 1, a protective agent bar was produced in the same manner as in Example 1 except that the protective agent bar was produced without using polytetrafluoroethylene, and was mounted on the image forming apparatus.
After image formation of 10,000 sheets, toner fixation was observed on the protective agent bars of all colors, and streaky abnormal images were generated in all the color images.

88 parts by weight of synthetic paraffin FT-115 (melting temperature 105 ° C., manufactured by Nippon Seiki) and 12 parts by weight of cyclic polyolefin TOPAS-TM (melting temperature 60 ° C., manufactured by Ticona) were put in a glass container with a lid, The mixture was melted with stirring by a hot stirrer whose temperature was controlled at 140 ° C. In this melt, 40 parts by weight of polytetrafluoroethylene particles having a number average particle size of 15 μm were mixed and stirred while maintaining a temperature of 140 ° C.
A protective agent bar mixed with polytetrafluoroethylene particles having a number average particle diameter of 15 μm was used for black of imagio Neo C385 and PCU of a magenta station. At this time, an electrostatic flocking brush made of polyester having a hair thickness of 10d was used as an application brush of the process cartridge, and a protective agent bar was pressed against the brush with a spring pressure of 3.0N.

In the same procedure as in Example 2, a protective agent bar was prepared using only polytetrafluoroethylene particles having a number average particle size of 55 μm. This protective agent bar was used for imagio Neo C385 yellow and cyan stations incorporating the protective agent bar prepared in Example 2. The conditions for the application brush are the same as in Example 2.
When 50,000 sheets of images were formed with imagio Neo C385 in which both protective agent bars prepared in Examples 2 and 3 were incorporated, all the protective agent bars had no toner fixation.
Further, in the black and magenta images, high-quality images were formed. However, when the yellow and cyan images were enlarged, a portion where the image was applied was observed.

In Example 2, instead of 40 parts by weight of polytetrafluoroethylene particles having a number average particle size of 15 μm, 5 parts by weight of polytetrafluoroethylene having a number average particle size of 40 μm and polytetrafluoroethylene having a number average particle size of 10 μm A protective agent bar was prepared in the same manner as in Example 2 except that 35 parts by weight of ethylene was mixed, and mounted on all color stations of imagio Neo C385. For the application brush of the process cartridge, a polyester electrostatic flocking brush having a bristle thickness of 10d was used by pressing the protective agent bar with a spring pressure of 3.0N.
When 50000 sheets of images were formed with imagio Neo C385, all the protective agent bars had no toner sticking. In addition, all color images were high-quality images.

In Example 2, instead of 40 parts by weight of polytetrafluoroethylene particles having a number average particle diameter of 15 μm, 20 parts by weight of polytetrafluoroethylene having a number average particle diameter of 10 μm and a polytetrafluoroethylene having a number average particle diameter of 0.5 μm are used. A protective agent bar was prepared in the same manner as in Example 2 except that 35 parts by weight of tetrafluoroethylene was mixed, and the bar was installed in all color stations of imagio Neo C385. For the application brush of the process cartridge, a polyester electrostatic flocking brush having a bristle thickness of 10d was used by pressing the protective agent bar with a spring pressure of 3.0N.
When 150,000 sheets of images were formed with imagio Neo C385, all the protective agent bars had no toner sticking. In addition, all color images were high-quality images.

In the column “Example 6”, “Example 6” is replaced with “Comparative Example 2”.
40 parts by weight of normal paraffin having a melting temperature of 64 ° C. and 20 parts by weight of microcrystalline wax having a melting temperature of 88 ° C. were placed in a glass container with a lid, and melted with stirring by a hot stirrer whose temperature was controlled at 120 ° C. In this melt, 20 parts by weight of polytetrafluoroethylene having a number average particle size of 2 μm was mixed and stirred while maintaining a temperature of 140 ° C.
The molten protective agent composition is poured into a mold, allowed to cool to 50 ° C. in a room temperature atmosphere, then reheated to 60 ° C. in a temperature-controlled thermostat, held at that temperature for 20 minutes, and then to room temperature. Allowed to cool.
According to this method, the protective agent bar could be produced without problems.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta process cartridges, and the protective agent bar is applied with a 2.5N spring pressure using an 8.5d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 7”, “Example 7” is replaced with “Comparative Example 3”. In the procedure of the production method of Comparative Example 2, a protective agent bar was produced in exactly the same procedure except that the amount of polytetrafluoroethylene having a number average particle diameter of 2 μm mixed in the melt was changed to 60 parts by weight. did. Even with this method, the protective agent bar could be produced without any problem.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta process cartridges, and the protective agent bar is applied with a 2.5N spring pressure using an 8.5d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 8”, “Example 8” is replaced with “Comparative Example 4”. In Comparative Example 2, a protective agent bar was produced in the same procedure except that the amount of polytetrafluoroethylene having a number average particle diameter of 2 μm was changed to 90 parts by weight.
During preparation with this procedure, when the protective agent composition is poured from the glass container into the mold, many protective agent compositions adhere to the glass container, so it is necessary to pour while heating the glass container to 120 ° C. was there. However, there was no problem with the manufactured protective agent bar.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta process cartridges, and the protective agent bar is applied with a 2.5N spring pressure using an 8.5d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 9”, “Example 9” is replaced with “Comparative Example 5”. In Comparative Example 2, a protective agent bar was produced in the same procedure except that the amount of polytetrafluoroethylene having a number average particle diameter of 2 μm was changed to 105 parts by weight.
During the preparation in this procedure, when pouring the protective agent composition from the glass container into the mold, even if it is heated to 120 ° C, the protective agent composition has a high viscosity and can be poured into the mold while being heated to 120 ° C. The surface of the protective agent bar had irregularities of 1 mm or more.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta process cartridges, and the protective agent bar is applied with a 2.5N spring pressure using an 8.5d polyester electrostatic flocking brush. Used by pressing.
In each of Comparative Examples 2 to 5, 500 color charts having an image density of 5% were copied and halftone images of each color were output. Other than those using a protective agent bar mixed with 105 parts by weight of polytetrafluoroethylene. Obtained a high-quality image. When staring at an image using a protective agent bar in which 105 parts by weight of polytetrafluoroethylene was mixed, there was a slight density unevenness, and the portion where the density irregularity occurred was roughly coincident with the concave portion of the protective agent bar.

In the column of “Example 10”, “Example 10” is replaced with “Comparative Example 6”. 11 parts by weight of cyclic polyolefin TOPAS-TM (melting temperature 60 ° C., manufactured by Ticona) and 89 parts by weight of paraffin having a melting temperature of 56 ° C. were mixed and melted with stirring by a hot stirrer whose temperature was controlled at 130 ° C. . In the melt, 46 parts by weight of polytetrafluoroethylene having a number average particle diameter of 2 μm was mixed and stirred while maintaining a temperature of 1400C.
The molten protective agent composition is poured into a mold, allowed to cool to 50 ° C. in a room temperature atmosphere, then reheated to 60 ° C. in a temperature-controlled thermostat, held at that temperature for 20 minutes, and then to room temperature. Allowed to cool.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta color process cartridges, and the protective agent bar is applied with a spring pressure of 2.8 N using an 8.2 d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 11”, “Example 11” is replaced with “Example 6”. A protective agent bar was produced in the same procedure as in Comparative Example 6 except that the paraffin had a melting temperature of 92 ° C.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta color process cartridges, and the protective agent bar is applied with a spring pressure of 2.8 N using an 8.2 d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 12”, “Example 12” is replaced with “Example 7”. A protective agent bar was produced in the same procedure as in Comparative Example 6 except that the paraffin had a melting temperature of 113 ° C.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta color process cartridges, and the protective agent bar is applied with a spring pressure of 2.8 N using an 8.2 d polyester electrostatic flocking brush. Used by pressing.

In the column “Example 13”, “Example 13” is replaced with “Example 8”. Of procedure of Comparative Example 6, except for changing the paraffin to that of melting temperature 124 ° C. was prepared protective agent bar with the same procedure.
The manufactured protective material bar is mounted on each of the imagio Neo C385 black, cyan, yellow, and magenta color process cartridges, and the protective agent bar is applied with a spring pressure of 2.8 N using an 8.2 d polyester electrostatic flocking brush. Used by pressing.
In each of Comparative Examples and Examples of Comparative Example 6 and Examples 6-8, after 300 sheet copying a color chart image concentration of 5% was output halftone image of each color, a melting temperature of 56 ° C. paraffin A high-quality image was obtained except for those using the protective agent bar. When using a paraffin protective bar having a melting temperature of 56 ° C., when spotted, spotted uneven density was slightly observed.
Remove the process cartridge of the color of the protective agent bar using paraffin having a melting temperature of 56 ° C., and replace the paraffin having a melting temperature of 113 ° C. with a process cartridge using the protective agent bar prepared by the above method. After 10000 color images with an image density of 3% were formed, and halftone images of each color were output, high-quality images were obtained.

According to the first aspect of the present invention, it is possible to provide an image forming apparatus in which the life of the photoconductor is long, the toner does not adhere to the protective agent bar, and there is no abnormal image and high quality image formation is possible .

It is the schematic of the protective layer formation apparatus structure which concerns on this invention. It is sectional drawing for demonstrating the outline of the process cartridge structural example using the protective layer forming apparatus which concerns on this invention. It is sectional drawing which shows an example of the image forming apparatus which comprises the protective layer forming apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Protective layer forming apparatus 3 Charging roller 4 Cleaning mechanism 21 Image carrier protective agent 22 Protective agent supply member 24 Protective layer forming mechanism 100 Image forming apparatus

Claims (1)

A protective agent supply member that can contact the image carrier, and a protective agent bar formed by a protective agent for protecting the surface of the image carrier is pressed against an application brush that is the protective agent supply member; the protective agent is shifted to the protective agent supplying member, it is migrated the protective layer form formed device and the AC voltage supplied to the protective agent the coating brush rubs the surface of the image bearing member to the image bearing member superimposed In an image forming apparatus having a charging roller to which a charged voltage is applied ,
The protective agent contains at least a paraffin having a melting temperature of 92 ° C. to 124 ° C. and polytetrafluoroethylene particles having a number average particle size of 0.3 μm to 55 μm , and the content of the polytetrafluoroethylene particles is 23. An image forming apparatus having a content of 1% by weight to 35.5% by weight.

Images