JP2002311639A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus which does not cause toner fusion on an a-Si (amorphous silicon) photoreceptor when a toner having positive chargeability with respect to the photoreceptor is used and which has a cleaning system free of defective cleaning and toner escape and having good cleaning performance. SOLUTION: In the electrophotographic system image forming apparatus in which an image is formed using an a-Si photoreceptor and single-component magnetic toner and the residual toner after transfer is removed with a cleaning unit, a positive charge type magnetic toner containing resin particles containing a bonding resin and a magnetic material and a negative charge type inorganic fine powder containing a rare earth fluoride compound and a rare earth oxide compound is used as the magnetic toner, the cleaning unit has a cleaning blade pressed on a rotating electrostatic latent image support and the cleaning blade is formed with an elastic member as a blade having 1±10 deg.C peak temperature of tan δ as its viscoelastic characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying machine, an information recording apparatus, etc., in which a latent image formed on an electrostatic latent image carrier is visualized with a developer. The present invention relates to an image forming apparatus having a cleaning device for collecting a developer remaining on a surface of an electrostatic latent image carrier after transferring a developer image onto transfer paper.

[0002]

2. Description of the Related Art A sheet-like transfer material such as paper is brought into contact with an electrostatic latent image carrier having a toner image electrostatically formed on a surface thereof.
In an image forming apparatus that repeats the process of transferring the toner image to a transfer material, not all of the toner on the electrostatic latent image carrier side is transferred to the transfer material at the time of transfer. It is necessary to remove residual toner on the surface of the carrier.

As a cleaning means for this purpose, a cleaning blade which is conventionally made of an elastic member such as rubber is pressed against an electrostatic latent image carrier at a position after transfer to scrape off residual toner, and more particularly, a magnetic toner is used. As means suitable for use, a device that shares a magnet roller has been proposed.

Conventionally, as an electrophotographic copying machine, a document image is exposed, the reflected light thereof is exposed to a photosensitive member (electrostatic latent image carrier) to obtain a latent image, and the latent image is then transferred to a toner. The analog method of developing using is generally used,
Further, as the toner, a negatively chargeable toner has been often used.

[0005] In an analog type electrophotographic copying machine using such a negatively charged toner, the material of the cleaning blade is tanδ of its viscoelastic characteristics.
Polyurethane rubber having a peak temperature of 1 ± 10 ° C. has been used. A cleaning blade having such characteristics has high rebound resilience, and has high rubber elasticity near the surface temperature of the photoreceptor. Therefore, when the blade is pressed against the photoconductor, the width of the blade in contact with the photoconductor (hereinafter, referred to as “nip width”) can be stably obtained, and the cleaning property is improved.

In recent years, however, a digital method has been used in which a document reflected light is converted into an electric signal, the signal is processed, and then a laser light, an LED light or the like is directly irradiated onto a photoreceptor based on the signal to form a latent image. An electrophotographic and electrostatic recording system using the same has been commercialized.

In many electrophotographic systems using digital image signals, a light-emitting body (such as a semiconductor laser) is turned on and off (ON-OFF) in accordance with the image signal, and the light is projected on a photoconductor. . At this time, the printing rate (the ratio of the printing area per page) is usually 30% or less, and the method of exposing the character portion, that is, the so-called reversal development, is superior in terms of the life of the luminous body. When forming a digital reversal latent image, when using a semiconductor laser or the like, 800 nm
A photoreceptor having a spectral sensitivity in a near infrared region is used.

As a photosensitive member having a spectral sensitivity in this region, there is an amorphous silicon (hereinafter referred to as "a-Si") photosensitive member. The a-Si photoreceptor has excellent durability such as heat resistance and friction resistance, and has a wide sensitivity range and high sensitivity, so that various laser beams can be used. It can be functionalized.

In order to perform digital reversal development using such an a-Si photosensitive member, it is necessary to use a positively charged toner as the toner. However, the positively chargeable toner has a good affinity for the surface of the a-Si photoreceptor, and the phenomenon called fixation of the toner on the surface (hereinafter, referred to as “fusion”) is particularly advanced under high temperature and high humidity. This occurs with When such toner fusion occurs, the conventionally used blade having a high rebound resilience has a poor ability to remove the toner fusion, so that the toner fusion may be further advanced.

In response to this phenomenon of toner fusion, a material having a tan δ peak temperature close to the surface temperature of a photoreceptor has been developed by recent material development. Such a blade has low rebound resilience and high hardness at the surface temperature of the photoreceptor. With such a blade having high hardness and low rebound resilience, the ability to scrape off the photoreceptor surface is improved as compared with a conventional blade having high resilience characteristics, and it is possible to scrape off toner fusion.

[0011]

However, such a blade having a high tan δ of viscoelasticity has a low rubber elasticity in a low temperature environment, the blade nip width with respect to the photoreceptor becomes unstable, poor cleaning, slip-through and the like. Problems easily occur.

Accordingly, the present invention provides a cleaning property that, when a positively charged toner is used for an a-Si photoreceptor, does not cause toner fusion on the photoreceptor and does not cause poor cleaning or slip-through. To provide an image forming apparatus having a good cleaning system.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned objects, the present invention provides a rotatable electrostatic latent image carrier having an amorphous silicon-based photosensitive layer, and a method for visualizing an electrostatic latent image with a magnetic toner. An image forming apparatus including a developing device that converts a toner image to a transfer material, a transfer device that transfers the toner image to a transfer material, and a cleaning device that removes magnetic toner remaining on the electrostatic latent image carrier after transfer. The toner is a positively chargeable magnetic toner containing resin particles containing a binder resin and a magnetic material, and a negatively chargeable inorganic fine powder containing a rare earth fluoride compound and a rare earth oxide compound. And a cleaning blade that is in pressure contact with the rotating electrostatic latent image carrier. The cleaning blade is formed of an elastic member, and has a viscoelastic property t of the blade.
Provided is an image forming apparatus, wherein an an δ peak temperature is 1 ± 10 ° C.

Normally, the magnetic toner remaining on the electrostatic latent image carrier accumulates in the nip portion of the cleaning blade. In the present invention, the magnetic toner contains inorganic fine powder. The inorganic fine powder acts as an abrasive and acts as abrasive particles on the electrostatic latent image carrier. Therefore, due to the polishing action of the inorganic fine powder, the magnetic toner does not adhere to the electrostatic latent image carrier, and the fusion of the toner can be prevented.

Further, since the occurrence of toner fusion can be prevented by the inorganic fine powder, it is not necessary to use a blade of high hardness and low resilience as a cleaning blade, and the peak temperature of tan δ of the viscoelastic characteristic is reduced. A low, high resilience blade can be used. Thereby, the rubber elasticity is maintained in a low temperature environment, and the cleaning property can be stably secured.

In the present invention, a cleaning blade having a tan δ peak temperature of 1 ± 10 ° C. is used. However, if the peak temperature is higher than this, cleaning performance in a low-temperature environment cannot be ensured, resulting in poor cleaning. Easier to do. Conversely, if the peak temperature is lower than this, the ability to scrape off the surface of the electrostatic latent image carrier is reduced, and toner adhesion is likely to occur.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the image forming apparatus of the present invention will be described. The image forming apparatus of the present invention includes a rotatable electrostatic latent image carrier having an amorphous silicon-based photosensitive layer, a developing device that visualizes the electrostatic latent image with a magnetic toner to form a toner image, and transfers the toner image. The transfer device includes a transfer device that transfers the toner onto the material, and a cleaning device that removes the magnetic toner remaining on the electrostatic latent image carrier after the transfer.

The electrostatic latent image carrier is not particularly limited as long as it has an amorphous silicon photosensitive layer.
A conventionally known a-Si based image carrier can be used as the electrostatic latent image carrier. Note that the amorphous silicon-based photosensitive layer is a photosensitive layer having a non-single-crystal structure containing silicon atoms as a base material. In addition to silicon atoms, hydrogen, halogen, oxygen, carbon, nitrogen, and dopants (III Group element, group V element, etc.).

The electrostatic latent image carrier decomposes the above-mentioned atom-containing source gas on a conductive substrate (preferably non-magnetic) such as aluminum or stainless steel by generating discharge.
It can be manufactured by a conventionally known method such as a plasma CVD method for forming the above-described layer containing atoms on a conductive substrate. The manufacturing conditions of the photosensitive layer may be appropriately determined depending on the performance required for the image forming apparatus.

The developing device is not particularly limited as long as it is a developing device used to visualize the electrostatic latent image on the electrostatic latent image carrier with a magnetic toner to form a toner image. It can be used in the present invention. Such a developing device includes, for example, a developing container containing a magnetic toner, a developing sleeve formed in a cylindrical shape, rotatably disposed at an opening of the developing container, carrying the magnetic toner on the surface thereof, and transporting the same. And a layer thickness regulating member for regulating the layer thickness of the magnetic toner carried on the developing sleeve.

The magnetic toner is a positively chargeable magnetic toner containing resin particles containing a binder resin and a magnetic material, and negatively chargeable inorganic fine powder. This magnetic toner will be described later in detail.

The transfer device is not particularly limited as long as it transfers the toner image formed on the electrostatic latent image carrier onto a transfer material such as plain paper or an OHP sheet. A known transfer device such as a roller transfer device can be used.

The cleaning device has a cleaning blade that presses against the rotating electrostatic latent image carrier. This cleaning blade is formed of an elastic member, and the peak temperature of tan δ of the viscoelastic characteristic of the blade is 1 ± 10 ° C.

Here, the tan δ peak temperature of the viscoelastic property is a change in tan δ with respect to the temperature and means the temperature at which tan δ takes the maximum value.
Can be measured using a viscoelasticity measuring device (for example, RSA2 (Rheometrics)).

Further, the cleaning blade preferably has a rubber hardness of 60 to 90 degrees. The rubber hardness of the cleaning blade can be measured using a Wallace rubber hardness meter or an Asker rubber hardness meter.

As the elastic member suitably used in the present invention, various known elastic members can be used, for example, urethane rubber. Among them, urethane rubber is most preferably used as the elastic member.
In the case where an elastic member as described above is used, the peak temperature of tan δ is determined, for example, by selecting the type of the elastic member to be used, using a reinforcing material such as a whisker, or using an elastic member mixed with another compound. Can be adjusted by selecting the mixing conditions.

It is preferable that the cleaning device has, in addition to the cleaning blade, a cleaning roller that comes into contact with the surface of the electrostatic latent image carrier before contacting the cleaning blade. More preferably, the cleaning roller includes a magnetic generating means.

The cleaning roller smoothes the residual magnetic toner on the electrostatic latent image carrier and stably supplies the magnetic toner to the cleaning blade. The cleaning roller is not particularly limited as long as it can be used. For example, a roller member having appropriate elasticity on the surface can be used as the cleaning roller.

The magnetism generating means attracts the residual magnetic toner on the electrostatic latent image carrier to the cleaning roller by magnetism, aggregates the magnetic toner, and more reliably removes the magnetic toner by the cleaning blade. There is no particular limitation as long as such an object can be achieved, and it may be one that generates a constant magnetism such as a magnet, or any magnet and magnetic pole such as an electromagnet. May be generated.

The image forming apparatus of the present invention is not particularly limited as long as it satisfies the above-mentioned components and the components of the magnetic toner described later. A charging device for charging an electrostatic latent image, an electrostatic latent image carrier Image forming apparatus (exposure apparatus) for forming a latent image on the charged surface of the sheet, a fixing apparatus for fixing an unfixed image on the transfer material, and an image history of the previous process by exposing the surface of the electrostatic latent image carrier after transfer And various devices, means, members, and the like, such as a pre-exposure device for erasing the image.

Further, according to the present invention, it is possible to form a process cartridge which is formed by integrally forming at least the developing device and the cleaning device, and which is detachably mounted on the image forming apparatus. The process cartridge can be configured by fixing a cleaning device, a developing device, and the like to a frame made of metal, resin, or the like, and making this frame removably attachable to the image forming apparatus main body. It should be noted that the device and the like configured as the process cartridge are not particularly limited, and the combination can be arbitrarily selected from the components of the image forming apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to the present embodiment (in the present embodiment, an image forming apparatus capable of forming a double-sided image by a through-pass double-sided method).

The image forming apparatus shown in FIG. 1 includes a photosensitive drum 1 which is driven to rotate in the direction of an arrow (clockwise) as an electrostatic latent image carrier, a charger 6 for charging the photosensitive drum 1, and a charged photosensitive drum 1. Exposure device 7, which is a latent image forming means for forming an electrostatic latent image, developing device 8, which visualizes the electrostatic latent image formed on photosensitive drum 1 with a magnetic toner to form a toner image, and transfers the toner image to a transfer material The image forming apparatus includes a transfer device 9 as a transfer device for transferring, a cleaning device for removing magnetic toner remaining on the photosensitive drum 1 after the transfer, and the like.

In the image forming apparatus, the transfer material containing the transfer material P is arranged in order from the upstream side in the transport direction of the transfer material P such as paper with the transfer portion between the transfer device 9 and the photosensitive drum 1 interposed therebetween. A cassette 10, a transport device 11 for transporting a transfer material carrying an unfixed toner image to the next stage, a fixing device 12 for fixing the toner image to the transported transfer material, and a reverse transport of the fixed transfer material as necessary. And a re-feeding belt 20 and the like.

The photosensitive drum 1 has an a-Si photosensitive layer on a cylindrical substrate made of metal (for example, aluminum), and is driven in a direction indicated by an arrow (clockwise) by driving means (not shown).
At a predetermined speed. Inside the photosensitive drum 1, a planar heating heater 2 is arranged for one round.
The temperature control of the photosensitive drum 1 by the heating heater 2 is performed by a thermistor 3 for detecting the temperature of the photosensitive drum 1 heated by the heating heater 2 and a power supply 4 based on the temperature information detected by the thermistor 3. Control device 5
The control is performed by the following. Further, the control device 5 controls the power supply from the power supply 4 to the heating heater 2 based on the environmental temperature / humidity information around the photosensitive drum 1 detected by the temperature / humidity detecting sensor 21 to keep the photosensitive drum 1 at a predetermined temperature. Set.

The surface of the photosensitive drum 1 is uniformly charged by the discharge of the charger 6. The charger 6 is a generally used corona discharge charger. However, in the present invention, the charger is not limited to the corona discharge charger, and may be a charge injection device such as a roller charger or a magnetic brush charger. A type charger may be used.

The exposure device 7 forms an electrostatic latent image by performing image exposure according to input image information on the photosensitive drum 1 charged by the charger 6. The charged photosensitive drum 1 receives an image exposure from the exposure device 7 to form an electrostatic latent image on its surface.

The developing device 8 is a developing device having the developing sleeve arranged to face the photosensitive drum 1. The magnetic toner carried and conveyed on the surface by the rotation of the developing sleeve moves toward the photosensitive drum 1 according to the electrostatic latent image at a portion facing the photosensitive drum 1 and adheres to the electrostatic latent image, The electrostatic latent image is visualized as a toner image. In addition,
The magnetic toner will be described later in detail.

The transfer unit 9 is a corona charger in the present embodiment. When the toner image on the photosensitive drum 1 arrives between the photosensitive drum 1 and the transfer device 9, the transfer material P fed from the transfer material cassette 10 is fed by a registration roller (not shown) at this timing. Then, the toner image formed on the photosensitive drum 1 is transferred to the transfer material P between the transfer device 9 and the photosensitive drum 1.

The transfer material P on which the toner image has been transferred is transported to the fixing device 12 by the transport device 11. Fixing device 1
Reference numeral 2 has a rotatable fixing roller 12a and a pressure roller 12b which are in contact with each other, and a heater (not shown) is provided in the fixing roller 12a. The transfer material P transported by the transport device 11 is fixed to the fixing roller 12a and the pressing roller 1a.
Introduced during 2b and subjected to heat and pressure. The toner image is transferred to the transfer material P by the heating and the pressing.

On the other hand, the untransferred magnetic toner remains on the photosensitive drum 1 after the transfer. The cleaning device is provided with a cleaning blade 13 that presses against the photosensitive drum 1. This cleaning blade 13
Is made of urethane rubber and has a tan δ peak temperature of viscoelasticity of 1 ± 10 ° C. The cleaning blade 13 contacts the photosensitive drum 1 and transfers the photosensitive drum 1 after the transfer.
The transfer residual toner remaining on the surface is removed. The removed magnetic toner is stored in a waste toner container (not shown).

At the time of one-sided image formation, the transfer material P is discharged to the outside as it is. At the time of double-sided image formation, the transfer material P having the toner image fixed on one side is transported onto the re-feed belt 20 by the reversing roller 14. Then, the transfer material P conveyed on the re-feed belt 20 is conveyed again to a transfer portion between the photosensitive drum 1 and the transfer device 9, and the above-described image is transferred to the other side on which the toner image is not transferred. After the image is formed in the same manner as in the forming process, the image is discharged to the outside.

FIG. 2 shows another embodiment of the image forming apparatus of the present invention. This image forming apparatus has the same configuration as the image forming apparatus shown in FIG. 1 except that the cleaning device is different. The cleaning device of the image forming apparatus includes:
In addition to the cleaning blade 13, a cleaning roller 15 that contacts the surface of the photosensitive drum 1 before contacting the cleaning blade is provided.

The cleaning roller 15 is a photosensitive drum 1
The transfer residual toner on the photosensitive drum 1 is scraped off by the rubbing, and the transfer residual toner is uniformly applied onto the photosensitive drum 1. Further, the toner adheres to the surface of the cleaning roller 15, and the inorganic fine powder in the toner also adheres to the surface of the cleaning roller 15, and the cleaning roller 15 polishes the photosensitive drum 1 moderately with the inorganic fine powder adhered. Accordingly, toner fusion can be further prevented.

When a magnet (not shown) is included in the cleaning roller 15, the cleaning roller 15 is attracted by the magnetic force of the magnet and polishes the photosensitive drum 1 by the cleaning roller 15 described above.
Further fusion of the toner can be prevented. If the toner is carried (attractive) on the cleaning roller 15 for a long time, agglomerates are likely to be generated.
And the toner may pass through. However, since the inorganic fine powder is present at the edge of the cleaning blade 13 to prevent intrusion of aggregates, the toner can be prevented from passing through.

FIGS. 1 and 2 show an embodiment of the image forming apparatus of the present invention. In the present invention, the object of the present invention is solved by using the above-mentioned image forming apparatus and the following magnetic toner. Can be. Next, the magnetic toner used in the present invention will be described.

The magnetic toner used in the present invention is a positively chargeable magnetic toner containing resin particles containing a binder resin and a magnetic material, and a negatively chargeable inorganic fine powder. First, the resin particles will be described.

As the binder resin used for the resin particles, conventionally known binder resins can be used, and the following polymers can be used. Examples of the binder resin include, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene, and polyvinyl toluene and a substituted product thereof; a styrene-p-chlorostyrene copolymer, a styrene-vinyltoluene copolymer, and styrene. -Vinyl naphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin and the like can be used. Preferred binder resins include styrene copolymers and polyester resins.

Examples of comonomers for the styrene monomer of the styrenic copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, and acrylic acid.
Monocarboxylic acid having a double bond such as 2-ethylhexyl, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide or the like; For example, dicarboxylic acids having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate and the like, and substituted products thereof; vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate and the like; Ethylene olefins such as ethylene, propylene and butylene; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl Vinyl ethers such as ether, such as vinyl monomers are used alone or two or more kinds.

The styrene-based polymer or styrene-based copolymer may be cross-linked by a cross-linking agent, or may be a mixed resin.

As a crosslinking agent for the binder resin, a compound having two or more polymerizable double bonds can be mainly used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; Divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups are used alone or as a mixture.

As a method for synthesizing the styrenic copolymer, known synthetic methods can be used. For example, any of bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and the like can be used. good.

In the bulk polymerization method, a polymer having a low molecular weight can be obtained by increasing the termination reaction rate by polymerizing at a high temperature, but there is a problem that the reaction is difficult to control.
In the solution polymerization method, a low molecular weight polymer can be easily obtained under mild conditions by utilizing the difference in radical chain transfer depending on the solvent and by adjusting the amount of the initiator and the reaction temperature.
It is preferable to obtain a low molecular weight polymer having a maximum molecular weight in a molecular weight range of 5,000 to 100,000 in the chromatogram of C.

As the solvent used in the solution polymerization method, xylene, toluene, cumene, cellosolve acetate, isopropyl alcohol, benzene and the like are used. In the case of a styrene monomer mixture, xylene, toluene or cumene is preferred. Such a solvent is appropriately selected depending on the polymer to be polymerized.

The reaction temperature in the solution polymerization method varies depending on the solvent used, the initiator and the polymer to be polymerized, but is preferably from 70 ° C. to 230 ° C. In solution polymerization, 30 parts by weight of monomer to 4 parts by weight of 100 parts by weight of solvent
It is preferably carried out at 00 parts by weight.

Further, it is preferable to mix another polymer in the solution at the end of the polymerization, and several kinds of polymers can be mixed well.

Further, as a polymerization method for obtaining a high molecular weight polymer or a crosslinked polymer having a maximum value of the molecular weight in the region of 300,000 to 5,000,000 in the GPC chromatogram, an emulsion polymerization method or a suspension polymerization method is preferable. .

Among them, the emulsion polymerization method is a method in which a monomer (monomer) almost insoluble in water is dispersed as small particles in an aqueous phase with an emulsifier, and polymerization is carried out using a water-soluble polymerization initiator. . In this method, the reaction heat can be easily adjusted, and the phase in which the polymerization is performed (oil phase composed of a polymer and a monomer)
And the aqueous phase are separate, so that the termination reaction rate is low, resulting in a high polymerization rate and a high degree of polymerization. Furthermore, due to the relatively simple polymerization process and the fact that the polymerization product is fine particles, in the production of toner,
This method is advantageous as a method for producing a binder resin for a toner as compared with other methods because it is easy to mix with a colorant, a charge control agent and other additives.

However, in the emulsion polymerization method, the resulting polymer tends to be impure due to the added emulsifier, and an operation such as salting out is required to take out the polymer. On the other hand, the suspension polymerization method is a simple method suitable for the above operation and the like. The suspension polymerization method is to disperse a polymerizable monomer in an aqueous solvent containing a dispersant as needed to form droplet particles, and to add a polymerization initiator at an optional stage before polymerization and polymerize. Is the way.

In the suspension polymerization method, the polymerization is preferably carried out with 100 parts by weight or less (preferably 10 to 90 parts by weight) of the monomer based on 100 parts by weight of the aqueous solvent. Examples of usable dispersants include polyvinyl alcohol, partially saponified polyvinyl alcohol, calcium phosphate, and the like. There is an appropriate amount in terms of the amount of a monomer relative to an aqueous solvent, and generally 0.05 to 1 based on 100 parts by weight of an aqueous solvent. Used in parts by weight. The polymerization temperature is suitably from 50 to 95 ° C, but should be appropriately selected depending on the initiator used and the intended polymer. As the initiator type, any initiator that is insoluble or hardly soluble in water can be used.

The initiator used in these polymerization methods described above includes t-butylperoxy-2-ethylhexanoate, cumin perpivalate, t-butylperoxylaurate, benzoyl peroxide, lauroyl peroxide. Octanoyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyro Nitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-
Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxycarbonyl) cyclohexane, 2,2 -Screw (t-
Butylperoxy) octane, n-butyl4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 1,3-bis (t-
Butylperoxy-isopropyl) benzene, 2,5-
Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylper Oxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-
Butylperoxycyclohexyl) propane, di-t-
Butyl peroxy α-methyl succinate, di-tert-butyl peroxydimethyl glutarate, di-tert-butyl peroxyhexahydroterephthalate, di-tert-butyl peroxyazelate, 2,5-dimethyl-2,5 −
Di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate),
Examples thereof include di-t-butylperoxytrimethyl adipate, tris (t-butylperoxy) triazine, and vinyltris (t-butylperoxy) silane, which can be used alone or in combination. The amount used is 0.05 parts by weight or more (preferably 0.1 to 15 parts by weight) with respect to 100 parts by weight of the monomer.

As the polyester resin used as the binder resin, those having the following composition can be used. Examples of the dihydric alcohol component include ethylene glycol, propylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5
-Pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, bisphenol represented by the formula (A) and derivatives thereof; and formula (B) And diols represented by the formula:

[0063]

Embedded image (Wherein R is an ethylene or propylene group, x,
y is an integer of 0 or more, and the average value of x + y is 0 to 10. )

Embedded image

As the divalent acid component, for example, phthalic acid,
Benzenedicarboxylic acids such as terephthalic acid, isophthalic acid and phthalic anhydride or their anhydrides and lower alkyl esters; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid and azelaic acid or their anhydrides and lower alkyl esters; n- Alkenyl succinic acids or alkyl succinic acids such as dodecenyl succinic acid and n-dodecyl succinic acid, or anhydrides and lower alkyl esters thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and itaconic acid or anhydrides and lower anhydrides And dicarboxylic acids and derivatives thereof such as alkyl esters.

It is preferable to use a trihydric or higher alcohol component and a trihydric or higher acid component which also serve as a crosslinking component. Examples of the trihydric or higher polyhydric alcohol component include sorbitol, 1,2,3,6-hexanetetrol,
1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,2
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2
-Methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxybenzene and the like.

Examples of the trivalent or higher polycarboxylic acid component include trimellitic acid, pyromellitic acid,
2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid,
2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8- Octanetetracarboxylic acid, empol trimer acid, and anhydrides and lower alkyl esters thereof;

Embedded image (Wherein X is an alkylene group or alkenylene group having 1 to 30 carbon atoms having at least one side chain having 1 or more carbon atoms), such as tetracarboxylic acids, and anhydrides and lower alkyl esters thereof. Examples include polyvalent carboxylic acids and derivatives thereof.

The alcohol component in the above-mentioned polyester resin is 40 to 60 with respect to the total amount of the polyester resin.
mol%, preferably 45 to 55 mol%, and the acid component is 60 to 40 mol based on the total amount of the polyester resin.
%, Preferably 55 to 45 mol%. It is also preferable that the trivalent or higher polyvalent component accounts for 1 to 60 mol% of all components.

In the magnetic toner used in the present invention, in addition to the above-mentioned binder resin component, the following compounds may be contained at a ratio smaller than the content of the binder resin component. For example, silicone resin, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, and a copolymer of two or more α-olefins are included.

The glass transition point (Tg) of the binder resin in the magnetic toner used in the present invention is preferably 45-8.
The temperature is 0 ° C, more preferably 50 to 70 ° C. It is preferable that the glass transition point of the binder resin be in the above range, in order to achieve both stability and fixability of the magnetic toner. The glass transition point was determined using ASTM (D3) using DSC-7 (manufactured by PerkinElmer) at a heating rate of 10 ° C./min.
418-82) can be measured according to the temperature setting pattern. In this case, the glass transition point is the intersection of the baseline before the endothermic peak, the middle line after the endothermic peak, and the rising curve from the DSC curve at the second temperature rise.

The magnetic toner used in the present invention preferably contains a wax in order to improve low-temperature fixability and high-temperature offset resistance.

Examples of the wax contained in the toner of the present invention include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin, polyolefin copolymer, microcrystalline wax, paraffin wax and sasol wax; Oxides of aliphatic hydrocarbon waxes such as polyethylene wax; or block copolymers thereof; waxes mainly containing fatty acid esters such as carnauba wax and montanic acid ester wax; fatty acid esters such as deoxidized carnauba wax And those in which some or all of the compounds are deoxidized. Further, saturated straight-chain fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a longer-chain alkyl group; unsaturated fatty acids such as brassic acid, eleostearic acid, and barinaric acid Saturated alcohols such as stearin alcohol, aralkyl alcohol, behenyl alcohol, carnaubyl alcohol, seryl alcohol, melisyl alcohol, or long-chain alkyl alcohols having a longer-chain alkyl group; polyhydric alcohols such as sorbitol; Fatty acid amides such as acid amide, oleic acid amide, lauric acid amide; saturated fatty acid bis such as methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebisstearic acid amide Bromide compounds,
Unsaturated fatty acid amides such as ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N, N'-dioleyladipamide, N, N'-dioleylsebacic acid amide; m-xylenebisstearic acid amide , N, N'-distearyl isophthalic acid amide and other aromatic bisamides; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metallic soaps); Waxes obtained by grafting hydrocarbon waxes with vinyl monomers such as styrene and acrylic acid; partially esterified products of fatty acids such as behenic acid monoglyceride and polyhydric alcohols; hydroxyls obtained by hydrogenation of vegetable oils and fats Methyl ester with a group Such compounds.

The wax preferably used is an alkylene polymer obtained by thermally decomposing a low molecular weight alkylene polymer or a high molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or polymerization under low pressure using a Ziegler catalyst or another catalyst. Polymers, those obtained by separating and purifying low molecular weight alkylene polymer by-produced when polymerizing the alkylene polymer, carbon monoxide, from the distillation residue of hydrocarbons obtained by the Atage method from synthesis gas consisting of hydrogen,
Alternatively, it is a wax obtained by extracting and separating a specific component from a synthetic hydrocarbon or the like obtained by hydrogenating them, and an antioxidant may be added to the wax. Alternatively, a linear alcohol, fatty acid, acid amide, ester or montan derivative is also preferably used as the wax. It is also preferable that impurities such as fatty acids have been removed in advance.

Among them, preferred are those obtained by polymerizing olefins such as ethylene, by-products at this time, and hydrocarbons having up to several thousands of carbon atoms, such as Fischer-Tropsch wax. Further, a long-chain alkyl alcohol having a hydroxyl group at a terminal having up to several hundred carbon atoms is also preferable. Further, those obtained by adding an alkylene oxide to an alcohol are also preferably used.

Then, from these waxes, the waxes are subjected to a press sweating method, a solvent method, a vacuum distillation, a supercritical gas extraction method, a fractional crystallization (for example, melt liquid crystal precipitation and crystal filtration), and the like, and the wax is converted to a molecular weight. A wax that has been fractionated and has a sharp molecular weight distribution is more preferable because the proportion of components in the necessary melting behavior range increases. Among them, the use of two or more kinds of waxes separated in this way, for low-temperature fixability, blocking resistance and high-temperature offset resistance,
It is particularly preferable in that a wax component having a melting behavior range necessary for improving these properties in a well-balanced manner can be contained in the toner without waste.

The magnetic toner used in the present invention preferably contains a positive charge control agent. Examples of the substance that controls the magnetic toner to be positively charged include denatured products such as nigrosine and fatty acid metal salts; and quaternary compounds such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. Ammonium salts, and onium salts such as phosphonium salts which are analogs thereof and their lake pigments, triphenylmethane dyes and these lake pigments,
(As a lake-forming agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.) Metal salts of higher fatty acids; dibutyltin oxide, dioctyltin oxide And diorganotin oxides such as dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guanidine compounds and imidazole compounds. These can be used alone or in combination of two or more. Among these, a triphenylmethane compound and a quaternary ammonium salt whose counter ion is not halogen are preferably used.

The general formula (1)

Embedded image [In the formula, R ₁ represents H or CH ₃ , and R ₂ and R ₃ represent a substituted or unsubstituted alkyl group (preferably, C ₁ -C ₄ ). Monomer of monomer represented by the following formula: A copolymer with a polymerizable monomer such as styrene, acrylate or methacrylate described above can be used as the positive charge control agent. In this case, these charge control agents also act as (all or part of) the binder resin.

Particularly, a compound represented by the following general formula (2) is preferable in the constitution of the present invention.

Embedded image [Wherein, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ each represent a hydrogen atom, which may be the same or different, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl. Represents a group. R ⁷ , R ⁸ and R ⁹ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group which may be the same or different from each other. A ^- is a sulfate ion, a nitrate ion,
Anions such as borate ion, phosphate ion, hydroxyl ion, organic sulfate ion, organic sulfonate ion, organic phosphate ion, carboxylate ion, organic borate ion, and tetrafluoroborate are shown. ]

In the magnetic toner used in the present invention, for the purpose of adjusting the chargeability of the magnetic toner and the like, a negative charge control agent may be used so as not to exceed the positive chargeability of the magnetic toner. To control the magnetic toner to be negatively charged,
For example, organometallic complexes, chelate compounds, monoazo metal complexes, acetylacetone metal complexes, metal complexes of aromatic hydroxycarboxylic acids, metal complexes of aromatic dicarboxylic acids, metal salts of aromatic hydroxycarboxylic acids, and aromatic polycarboxylic acids Examples thereof include metal salts, anhydrides thereof, esters thereof, and phenol derivatives.

Further, an azo metal complex represented by the following general formula (3) is also preferable as the negative charge control agent.

Embedded image [Wherein, M represents a coordination center metal, and Sc, Ti, V, C
Indicates r, Co, Ni, Mn or Fe. Ar is an aryl group, and represents a phenyl group or a naphthyl group. Ar may have a substituent. In this case, the substituent is a nitro group,
A halogen group, a carboxyl group, an anilide group and an alkyl or alkoxy group having 1 to 18 carbon atoms. X,
X ', Y and Y' are -O-, -CO-, -NH- or-
NR- (R is an alkyl group having 1 to 4 carbon atoms). K represents a cation ion, and hydrogen, sodium, potassium,
Ammonium or aliphatic ammonium. There may be no cation ion. ]

In particular, the central metal is preferably Fe or Cr, the substituent is preferably a halogen, an alkyl group or an anilide group, and the counter ion is preferably hydrogen, alkali metal ammonium or aliphatic ammonium. Also, a mixture of complex salts having different counter ions is preferably used.

The basic organic acid metal complex represented by the following formula (4) is also preferable as the negative charge control agent.

Embedded image

In particular, Fe, Cr, Si,
Zn or Al is preferable, and the substituent is an alkyl group,
Anilide groups, aryl groups or halogens are preferred, and the counter ion is preferably hydrogen, ammonium or aliphatic ammonium.

As a method for incorporating the charge control agent into the magnetic toner, there are a method of adding the charge control agent inside the magnetic toner and a method of externally adding the charge control agent. The amount of use of these charge control agents is determined by the type of the binder resin, the presence or absence of other additives, the toner manufacturing method including the dispersion method, and is not limited uniquely. Preferably, it is used in the range of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the binder resin.

A colorant can be further used in the magnetic toner used in the present invention. Colorants that can be used in the magnetic toner include any suitable pigment or dye. For example, examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, hansa yellow, rhodamine lake, alizarin lake, bengalah, phthalocyanine blue, indanthrene blue, and the like. These are used in amounts necessary and sufficient to maintain the optical density of the fixed image, and are preferably added in an amount of 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the resin. A dye is further used for the same purpose. Examples include azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes.
0.1 to 20 parts by weight, preferably 0.1 to 20 parts by weight, based on 0 parts by weight.
Addition of 3 to 10 parts by weight is good.

A magnetic material is used for the magnetic toner used in the present invention. The magnetic material can also serve as a colorant. In the present invention, as a magnetic material used when constituting a magnetic toner, iron oxides of magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; or these metals and aluminum, cobalt, copper, lead, and magnesium , Tin, zinc, antimony,
Examples include alloys with metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures thereof.

These magnetic materials preferably have an average particle diameter of 2 μm or less, preferably about 0.1 to 0.5 μm. As the amount contained in the magnetic toner, the resin component 1
Preferably about 20 to 200 parts by weight,
Particularly preferred is 40 to 150 parts by weight. It is preferable that the average particle size and the content of the magnetic material be in the above ranges in order to improve the uniform dispersibility of the magnetic material and the fluidity and the fixing property of the magnetic toner.

Further, the saturation magnetization of these magnetic materials is from 5 Am ² / kg (5 emu / g) to 200 Am ² / k in a magnetic field of 7.96 × 10 ² kA / m (10 kOe).
g (200 emu / g), and further 10 Am ² / kg
(10 emu / g) to 150 Am ² / kg (150 em
u / g) is preferable in improving the fluidity and fixability of the magnetic toner.

The residual magnetization of the magnetic material is 7.96 ×
In a magnetic field of 10 ² kA / m (10 kOe), 1 Am ² / kg
(1 emu / g) to 100 Am ² / kg (100 emu / g)
/ G), more ^{1Am 2 / kg (1emu / g} ) ~7
It is preferably 0 Am ² / kg (70 emu / g) for improving the fluidity and fixability of the magnetic toner.

The magnetic properties of the magnetic material, such as saturation magnetization and residual magnetization, were measured using an external magnetic field of 7.96 × 10 ² using a “vibrating sample magnetometer VSM-3S-15” (manufactured by Toei Industry Co., Ltd.). k
It is a value measured under A / m (10 kOe).

The resin particles containing the above components can be produced by a known method. For example, a binder resin, a magnetic substance, a wax, a charge control agent, and other additives are mixed with a Henschel mixer, a ball mill or the like. After thoroughly mixing with a heating machine, a heating roll, a kneader, melt-kneading using a hot kneading machine such as an extruder to disperse or dissolve the constituents while the resins are mutually compatible, and cooled and solidified,
It can be manufactured by a pulverization method in which pulverization and classification by air classification or the like are performed.

Further, the resin particles may be produced by a polymerization method such as the suspension polymerization method described above. In the case of producing resin particles by a suspension polymerization method, it is preferable to perform a hydrophobic treatment with a silane coupling agent or silicone oil that can coat the magnetic material by bonding to the surface of the magnetic material. Further, in the case of producing resin particles by a suspension polymerization method, it is preferable to use a binder resin having a relatively low polarity such as a styrene-based resin and the above-mentioned polyester resin in combination.

Further, the magnetic toner used in the present invention can be obtained by sufficiently mixing inorganic fine powder and other additives with the resin particles obtained as described above using a mixer such as a Henschel mixer. .

In the present invention, the weight average particle diameter of the magnetic toner is preferably 4 to 13 μm, more preferably 5 to 13 μm.
The thickness is preferably 12 μm. When the weight average particle diameter of the magnetic toner is less than 4 μm, it is difficult to obtain a sufficient image density. When it exceeds 13 μm, it is difficult to form a higher definition image.

The weight average particle diameter of the magnetic toner can be measured using a Coulter Counter TA-II (manufactured by Coulter), but it is also possible to use a Coulter Multisizer (manufactured by Coulter). As the electrolytic solution, a 1% NaCl aqueous solution is prepared using primary sodium chloride. For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used.

As a specific example of the measurement method, 0.1 to 5 mL of a surfactant, preferably an alkylbenzene sulfonate, is used as a dispersant in 100 to 150 mL of the electrolytic aqueous solution.
In addition, 2 to 20 mg of the measurement sample is further added. The electrolytic solution in which the sample was suspended was subjected to dispersion treatment for about 1 to 3 minutes using an ultrasonic disperser, and the measurement apparatus used an aperture of 100 μm as an aperture.
The volume distribution and the number distribution are calculated by measuring the volume and the number of the toner having a size of 2.00 μm or more using an aperture, and the weight-average weight-average particle diameter (D4) (each of which is obtained from the volume distribution according to the present invention) is calculated. The median value of the channel is set as a representative value for each channel).

The above channels are 2.00 to
2.52 μm or less; 2.52 to 3.17 μm or less;
17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6.35 to 8.00.
less than μm; 8.00 to less than 10.08 μm; 10.08
-12.70 μm; 12.70-16.00 μm; 16.00-20.20 μm; 20.20-2
Less than 5.40 μm; 25.40 to less than 32.00 μm;
It is preferable to use 13 channels of 32.00 to less than 40.30 μm.

Next, the inorganic fine powder contained in the magnetic toner used in the present invention will be described. The inorganic fine powder used in the present invention is a negatively chargeable inorganic fine powder containing a rare earth fluoride compound and a rare earth oxide compound.

The rare earth fluoride compound mainly affects the chargeability of the magnetic toner, and the rare earth oxide compound is
It mainly affects cleaning performance of the electrostatic latent image carrier. As the rare earth elements contained in these compounds, various rare earth elements having negative chargeability can be used, and examples of such rare earth elements include rare earth elements such as Ce, La, Nd, and Pr. it can.

The inorganic fine powder contains a rare earth oxide compound in a total amount of 88.0 to 97.0 with respect to the total amount of the inorganic fine powder.
% By mass (preferably 89.0 to 96.0% by mass, more preferably 90.0 to 95.0% by mass). When the content of the rare earth oxide compound is within the above range, fusion and image deletion can be effectively prevented. When the content of the rare earth element compound is less than 88.0% by mass, the polishing effect tends to exhibit unevenness. When the content of the rare earth element compound exceeds 97.0% by mass, lubricity is affected. In some cases, cleaning stability and polishing effect stability may be lost.

The rare earth oxide compound is 4% in terms of oxide with respect to the total amount of the rare earth oxide compound.
0.0 to 65.0% by mass of CeO ₂ , 25.0 to 45.
0 wt% La ₂ O _3, 1.0 to 10.0 wt% Nd ₂
It is preferable to contain O ₃ and 1.0 to 10.0% by mass of Pr ₆ O ₁₁ .

The CeO ₂ content is from 40.0 to 6
When the content is 5.0% by mass (preferably 45.0 to 65.0% by mass, and more preferably 50.0 to 63.0% by mass), the polishing effect and the lubrication effect can be balanced and stable. Developability is obtained. If the content of CeO ₂ is larger than the above range, the shaving amount of the electrostatic latent image carrier becomes too large, and the life of the image carrier is shortened, the shaving method becomes uneven, and the uniformity of the surface potential is lost. This may cause unevenness in image density. Further, the magnetic toner may be excessively charged to cause a decrease in image density. On the other hand, when the content of CeO ₂ is smaller than the above range, the lubricating property becomes poor, and the cleaning blade may be chattered or turned up. Further, the chargeability of the toner may be uneven and the image density may be unstable.

The content of La ₂ O ₃ is 25.0-4.
When the content is 5.0% by mass (preferably, 27.0 to 43.0% by mass, and more preferably, 30.0 to 40.0% by mass), the fluidity of the magnetic toner can be stabilized. The waste toner has a large fluidity stabilizing effect. La ₂
When the content of O ₃ is smaller than the above range, the toner fluidity in the cleaner tends to be unstable, whereby
Toner may leak from both ends of the cleaner blade onto the electrostatic latent image carrier, causing the toner to fuse to the end of the image carrier. If the content of La ₂ O ₃ exceeds the above range, the fluidity becomes unstable, the movement of the waste toner in the cleaner becomes poor, the discharge cannot be performed well, and the toner may be clogged. . Further, toner may be clogged at the blade edge portion, causing the blade to float and induce cleaning failure.

The content of Nd ₂ O ₃ is 1.0 to 1.0.
When the content is 0% by mass (preferably 1.0 to 8.0% by mass, more preferably 2.0 to 5.0% by mass), the retention of the inorganic fine powder at the blade edge portion is stabilized, and the cleaning property is improved. It can stabilize and prevent poor cleaning. Further, since the retention is stabilized, the fusion and the prevention of the image deletion are more effectively performed. When the content of Nd ₂ O ₃ is out of the above range, the inorganic fine powder is not stably present at the edge portion of the cleaner blade, so that aggregates generated in the cleaner are generated between the blade and the electrostatic latent image carrier. Pinched,
Magnetic toner slips easily. In addition, the blade edge surface is exposed, causing a sudden change in the friction coefficient, causing the blade to vibrate, etc., and may cause cleaning failure due to toner slippage. If the content of Nd ₂ O ₃ is larger than the above range, the amount of inorganic fine powder transferred together with the toner particles increases, and the supply to the blade edge may decrease. On the other hand, if the content of Nd ₂ O ₃ is smaller than the above range, it tends to move together with the waste toner, and the stagnation at the blade edge may become unstable.

The content of Pr ₆ O ₁₁ is 1.0 to 1
When the content is 0.0% by mass (preferably 2.0 to 9.0% by mass, more preferably 3.0 to 8.0% by mass), the charging stability of the magnetic toner is provided. If the content of Pr ₆ O ₁₁ is larger than the above range, the inorganic fine powder is liable to be overcharged, the electrostatic adhesion is increased, and the toner may be fused to the electrostatic latent image carrier. is there. Pr ₆ O ₁₁
If the content is smaller than the above range, the inorganic fine powder may adsorb the fine toner particles and become fog particles, thereby causing spot-like fog.

The inorganic fine powder contains 2.0 to 11.0 of rare earth fluoride compound in total with respect to the total amount of the inorganic fine powder.
When the amount is at most 3.0% by mass, and more preferably at most 4.0% by mass, the charge amount of the magnetic toner can be stabilized, and the durability of development can be improved. Is obtained. Particularly, in the case of a positively chargeable magnetic toner, the charge amount can be increased. When the content of the rare earth fluoride rare earth element compound is larger than the above range, when a negatively chargeable toner is used as the magnetic toner, the charge balance tends to be lost,
This tends to cause image density reduction and fogging.
Further, the polishing property may be insufficient. If the content of the rare earth fluoride compound is smaller than the above range, when a positively chargeable toner is used as the magnetic toner, the charge balance is easily lost, and the image density is easily reduced and fog is easily caused. Further, the ratio of the rare earth oxide compound in the inorganic fine powder increases, the polishing property increases, and the life of the electrostatic latent image carrier may be shortened.

The rare earth fluoride compound is not particularly limited as long as it is a compound in which at least the rare earth element and the fluorine element are bonded, and may contain other elements in addition to the rare earth element and the fluorine element. . Such a rare earth element compound is obtained by fluorinating the rare earth element compound, for example, by mixing the rare earth element compound and hydrofluoric acid and firing.

Further, in the present invention, the magnetic toner preferably contains the inorganic fine powder in an amount of 0.1 to 10.0% by mass. When the content of the inorganic fine powder is less than 0.1% by mass, its appearance effect is small, which is not preferable. When the content of the inorganic fine powder exceeds 10.0% by mass,
Uneven distribution and release of the inorganic fine powder in the magnetic toner are apt to occur, and when used for a long time, the electrostatic latent image carrier is scraped non-uniformly, which causes variation in the friction coefficient of the surface of the image carrier. It is easy to cause poor cleaning.

Further, the inorganic fine powder used in the present invention has a volume average particle size of 0.1 to 4.0 μm (preferably 0.2 to 4.0 μm).
2.0 μm) and a BET specific surface area by a nitrogen gas adsorption method of 0.5 to 15.0 m ² / g (preferably 1.0 to
10.0 m ² / g). When the volume average particle size is less than 0.1 μm, the cohesiveness of the inorganic fine powder is increased, and the fluidity of the toner tends to be adversely affected. Further, when the volume average particle size exceeds 4.0 μm, it is difficult to obtain the polishing effect. Further, the BET specific surface area is 15.0 m ² /
When the amount exceeds g, the moisture resistance of the inorganic fine powder tends to decrease, and particularly, the developability in a high humidity environment tends to decrease. Further BE
When the T specific surface area is less than 0.5 m ² / g, it is difficult to obtain a polishing effect.

When the inorganic fine powder is used for a positively chargeable toner, its effect is well exhibited. Further, as the inorganic fine powder, other powders or particles suitable as an external additive of the magnetic toner may be used as long as the positive charging of the magnetic toner is not hindered.

Conventionally, strontium titanate or general cerium oxide has been used as an abrasive frequently used as an external additive of a magnetic toner. However, when these abrasives are used for a positively chargeable toner, an insufficient amount of charge is required. , And easy to cause uneven charging. It is usually because the binder resin used for the magnetic toner is negatively charged, and in the case of the positively chargeable toner, a positively chargeable charge control agent is dispersed in the binder resin to obtain a positively triboelectrically charged toner. Compared with negatively chargeable toner,
This is because it is difficult to balance the charge.
However, the inorganic fine powder used in the present invention does not cause charging inhibition and can maintain uniform charging.

As described above, the inorganic fine powder has a better balance of abrasiveness and lubricity than conventional general cerium oxide and strontium titanate, and can stably clean the electrostatic latent image carrier with the cleaning member. And the occurrence of defective cleaning can be reduced. Hereinafter, a measurement method for the inorganic fine powder used in the present invention will be described.

(1) Measurement of Content of Rare Earth Element Compound In the present invention, the content of the rare earth element compound in the inorganic fine powder can be measured by an oxalate weight method. For example, about 0.5 g of a sample, 15 mL of HClO ₄ , H ₂ O ₂
, Add 1 mL, stir gently, warm on a hot plate,
Decompose and concentrate to about 5 mL. In addition, add about 50 pure water.
Add mL and boil, then filter and wash with warm water several times so that the filtrate becomes about 250 mL. Obtained filtrate 250
Add oxalic acid 5.0 g while heating to mL, stir,
After completely dissolving, allow to cool and adjust the pH with NH ₄ OH and HCl.
Adjust to 1.3-1.5. Thereafter, filtration and washing were performed, and the obtained precipitate was transferred to a porcelain crucible, dried at 140 ° C. for about 1 hour, and then incinerated at 1000 ° C. for about 1 hour in an electric furnace to remove the rare earth compound. obtain. This is weighed, and the content is calculated from the initial weight of the inorganic fine powder.

(2) Measurement of Content of Each Rare Earth Oxide in Rare Earth Compound In the present invention, CeO ₂ ,
The content of _{La 2 O 3, Nd 2 O} 3, Pr 6 O 11 uses a rare earth element compound obtained in (1), JlS K0116
Hijacking emission spectroscopy, plasma emission analysis (IC
P analysis) and calculated in terms of oxide.
The contents of U and Th were obtained as element contents.

(3) Measurement of Fluorine Content of Inorganic Fine Powder In the present invention, the fluorine content of the inorganic fine powder can be measured as follows. For example, 0.5 g of inorganic fine powder is precisely weighed, and 5 mL of special grade NaOH and 5 m of pure water are used.
Add L and heat to dissolve. After cooling, add pure water and add 100m
L. Buffer solution (1.5L distilled water)
100 mL of acetic acid, 116 g of sodium chloride and 2 g of sodium citrate) were added to 50 mL of
Put into a 00 mL volumetric flask to make up the volume. The fluorine content of this aqueous solution was measured by an ion meter.

(4) Measurement of Volume Average Particle Size of Inorganic Fine Powder In the present invention, the volume average particle size of the inorganic fine powder is determined by a laser diffraction particle size measurement (microtrack method).
Represents the 0% value.

(5) Measurement of BET Specific Surface Area of Inorganic Fine Powder The BET specific surface area was measured using Yuasa Ionics Co., Ltd., fully automatic gas adsorption measuring device: Autosoap 1, using nitrogen as the adsorbed gas, and Determined by the multipoint method. In addition, as pretreatment of a sample, deaeration is performed at 50 ° C. for 6 hours.

[0117]

EXAMPLES Hereinafter, production examples of the inorganic fine powder and the magnetic toner used in the present example will be described specifically, but this does not limit the present invention in any way.

<Production Example 1 of Inorganic Fine Powder> Bastnaesite concentrate is pulverized, dissolved with sulfuric acid, and then converted into a carbonate of a rare earth element, followed by firing to obtain a rare earth oxide compound. After cooling, add hydrofluoric acid while performing wet grinding, and after drying,
In an electric furnace, bake at 600 to 1000 ° C. for 5 to 10 hours,
Through the pulverization and classification steps, inorganic fine powder A-1 of Production Example 1 as shown in Table 1 was obtained.

[0119]

[Table 1]

<Production Example 1 of Magnetic Toner> 100 parts by weight of styrene butyl acrylate copolymer (binder resin) 90 parts by weight of magnetic iron oxide (magnetic substance) 90 parts by weight of triphenylmethane lake pigment (positive charge control agent) 2 parts by weight-Low molecular weight polyethylene (release agent) 4 parts by weight After the above materials were premixed with a Henschel mixer, 130 parts by weight
The mixture was melt-kneaded by a twin-screw kneading extruder set at a temperature of ° C. The obtained kneaded material was cooled, coarsely pulverized by a canter mill, then pulverized by a fine pulverizer using a jet stream, and the obtained finely pulverized powder was classified using a multi-segment classifier utilizing the Coanda effect. A resin particle having a volume average particle diameter of 7.2 μm was obtained. 3.0 parts by weight of the inorganic fine powder A-1 was externally added and mixed with 100 parts by weight of the resin particle to obtain a positively chargeable toner α.

<Comparative Production Example of Magnetic Toner> Inorganic Fine Powder A
Positively chargeable toner β was produced in the same manner as in Magnetic toner production example 1 except that -1 was not externally added.

<Example 1 and Comparative Example 1> The positively chargeable toners α and β produced in the magnetic toner production example 1 and the magnetic toner comparative production example 1 were applied to the image forming apparatus shown in FIG.
In an environment with a temperature of 23 ° C. and a humidity of 60% RH (normal temperature and normal humidity), 5
A copy test was performed on 5,000 sheets, and the cleaning property and toner fusion were evaluated.

As the test conditions, the temperature control of the photosensitive drum 1 was set to 50 ° C., which was higher than the normal control of 42 ° C., and the conditions were such that toner fusion was accelerated. In the present embodiment and the comparative example, as the photosensitive drum 1, an a-
A Si drum was used. Cleaning blade 1
3, the peak temperature of the viscoelastic property tan δ is 1 ° C.,
Urethane rubber having a rubber hardness of 76 ° and a thickness of 3 mm was used. Table 2 shows the results.

[0124]

[Table 2]

As can be seen from the evaluation results, the temperature control of the photosensitive drum 1 is set to be higher than usual, and the condition of the positive charging of the present embodiment is set despite the condition that the toner fusion is more likely to occur. In the case of the non-volatile toner α, toner fusion did not occur, and there was no occurrence of poor cleaning or slip-through. On the other hand, in the case of the positively chargeable toner β shown in the comparative example, toner fusion occurred from 15,000 sheets, and
After the endurance of the sheet, the number of toner fusion increases to 13 pieces.

As can be seen from the above description, in the present invention, the magnetic toner contains inorganic fine powder, which acts as abrasive particles on the photoreceptor. Can be prevented. Further, the action of the inorganic fine powder eliminates the occurrence of toner fusion, so that it is not necessary to use a material having a peak temperature of tan δ of viscoelastic characteristic close to the surface phoneme of the photoreceptor as a material of the cleaning blade. Good ta
Those having a low peak temperature of nδ can be selected.
Therefore, it is possible to establish a cleaning system in which toner fusion does not occur and cleaning failure and slip-through do not occur.

<Embodiment 2> In this embodiment, as shown in FIG. 2, a cleaning device having a cleaning roller in addition to a cleaning blade was used. Except for the provision of the cleaning roller, the operation was the same as in the first embodiment. Conventionally, the cleaning roller is installed upstream of the cleaning blade in the rotation direction of the photoconductor to stably supply toner to the cleaning blade, and scrapes off the residue on the photoconductor by rubbing and applies the toner to the photoconductor. I do. On the cleaning roller surface, residual toner on the photoconductor is carried,
By using the above-described positively chargeable toner α, the inorganic fine powder A-1 polishes the photoreceptor moderately on the surface of the cleaning roller, thereby further preventing the toner from being fused to the photoreceptor.

<Embodiment 3> This embodiment is the same as Embodiment 2 described above except that the cleaning roller of Embodiment 2 includes a magnetism generating means. When the cleaning roller includes the magnetic generating means, its performance is further enhanced. In this case, since the positively chargeable toner α strongly adheres to the cleaning roller by the magnetic force, the positively chargeable toner α is stirred on the roller for a long time, and aggregates are easily generated. Normally, the aggregates are caught between the cleaning blade and the photoreceptor, causing toner to pass through. However, since the inorganic fine powder A-1 is present at the edge of the cleaning blade and prevents intrusion of the aggregates, the inorganic fine powder A-1 prevents toner from passing through. Can be prevented.

[0129]

As described above, according to the present invention,
A rotatable electrostatic latent image carrier having an amorphous silicon-based photosensitive layer, a developing device that visualizes the electrostatic latent image with a magnetic toner to form a toner image, a transfer device that transfers the toner image to a transfer material, In an image forming apparatus having a cleaning device that removes a magnetic toner remaining on the electrostatic latent image carrier after transfer, the magnetic toner includes resin particles containing a binder resin and a magnetic material, a rare earth fluoride compound, A positively-chargeable magnetic toner containing a negatively-chargeable inorganic fine powder containing a rare-earth oxide compound and a cleaning device,
A cleaning blade that is in pressure contact with the rotating electrostatic latent image carrier; the cleaning blade is formed of an elastic member; and the tan δ peak temperature of the viscoelastic characteristic of the blade is 1 ± 10 ° C. Therefore, even when an amorphous silicon photoconductor is used and a latent electrostatic image on the a-Si photoconductor is visualized with a positively charged magnetic toner, the toner is fused to the a-Si photoconductor. It is possible to provide an image forming apparatus having a cleaning system in which no cleaning occurs and no cleaning failure or slip-through occurs.

According to the present invention, in the cleaning device, the elastic member is made of urethane rubber, and in addition to the cleaning blade, a cleaning roller that comes into contact with the surface of the electrostatic latent image carrier before the cleaning blade comes into contact with the cleaning roller. And the cleaning roller satisfies at least one of the conditions that the cleaning roller includes the magnetic generation means, thereby providing an image forming apparatus with further improved cleaning performance for the electrostatic latent image carrier. .

Further, according to the present invention, in the magnetic toner, the inorganic fine powder in the magnetic toner is 2.0 to 11.0% by mass in total with respect to the total amount of the inorganic fine powder, and 88.0 to 97.0% by mass of the rare earth oxide compound, wherein the rare earth oxide compound is 4% in terms of oxide with respect to the total amount of the rare earth oxide compound.
0.0 to 65.0% by mass of CeO ₂ , 25.0 to 45.
0 wt% La ₂ O _3, 1.0 to 10.0 wt% Nd ₂
O ₃ and 1.0 to 10.0 mass% of Pr ₆ O ₁₁ , and the magnetic toner contains 0.1 to 10.0 mass% of inorganic fine powder with respect to the total amount of the magnetic toner. By satisfying at least one of the above, it is possible to provide an image forming apparatus that is more effective in improving the cleaning property for the electrostatic latent image carrier.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an image forming apparatus of the present invention.

FIG. 2 is a schematic configuration diagram illustrating another embodiment of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Heating heater (heating means) 3 Thermistor 4 Power supply 5 Control device 6 Charger 7 Exposure device 8 Developing device 9 Transfer device 10 Transfer material cassette 11 Transport device 12 Fixing device 12a Fixing roller 12b Pressure roller 13 Cleaning blade 14 Reversing roller 15 Cleaning roller 20 Refeed belt 21 Temperature / humidity detection sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 9/08 101 F term (Reference) 2H005 AA08 CB07 CB10 DA03 EA07 FA02 FA06 2H068 DA03 DA13 FC02 FC20 2H134 GA01 HD05 HD19 KD08 KG07 KG08 MA04 MA07 MA09

Claims (6)

[Claims] 1. A rotatable electrostatic latent image carrier having an amorphous silicon-based photosensitive layer, a developing device for visualizing the electrostatic latent image with a magnetic toner to form a toner image, and the toner image on a transfer material An image forming apparatus comprising: a transfer device for transferring, and a cleaning device for removing a magnetic toner remaining on the electrostatic latent image carrier after the transfer, wherein the magnetic toner includes a binder resin and a magnetic material A positively-chargeable magnetic toner containing resin particles and an inorganic fine powder containing a rare earth fluoride compound and a rare earth oxide compound, wherein the cleaning device is a cleaning blade that presses against a rotating electrostatic latent image carrier. The cleaning blade is formed of an elastic member, and the peak temperature of tan δ of the viscoelastic characteristic of the blade is 1 ± 10 ° C. . 2. The image forming apparatus according to claim 1, wherein said elastic member is urethane rubber. 3. The cleaning device according to claim 1, wherein the cleaning device further includes, in addition to the cleaning blade, a cleaning roller that contacts a surface of the electrostatic latent image carrier before contacting the cleaning blade. The image forming apparatus as described in the above. 4. The image forming apparatus according to claim 3, wherein the cleaning roller includes a magnetic generation unit. 5. The inorganic fine powder in the magnetic toner has a total amount of 2.0 to 11.0 mass% of the rare earth fluoride compound and 88.0 to 97.0 mass% of the inorganic fine powder with respect to the total amount of the inorganic fine powder. The rare earth oxide compound contains 40.0 to 65.0% by mass of CeO ₂ , in terms of oxide, based on the total amount of the rare earth oxide compound.
0 to 45.0% by weight of La ₂ O _3, 1.0 to 10.0 wt% of Nd ₂ O _3, and 1.0 to 10.0% by weight of Pr ₆ O
The image forming apparatus according to claim 1, further comprising: ₁₁ . 6. The image forming apparatus according to claim 1, wherein the magnetic toner contains 0.1 to 10.0% by mass of inorganic fine powder based on the total amount of the magnetic toner.