JP2015040878A - Charging apparatus and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging apparatus configured to maintain cleaning property of a charging member with a simple configuration without complicating or enlarging a structure, to prevent reduction in charging characteristics, while preventing an abnormal image.SOLUTION: A charging apparatus includes: a charging member to be used for uniformly charging a latent image carrier surface; and a cleaning member for removing a foreign substance deposited on a surface of the charging member, in contact with the surface of the charging member. The cleaning member is configured to select a first mode or a second mode as a driven rotation state with respect to the charging member, by changing contact pressure with respect to the charging member. In the second mode, a relation is set so that a linear velocity ratio of the cleaning member with respect to the charging member is larger than in the first mode.

Description

  The present invention relates to a charging device and an image forming apparatus, and more particularly to a cleaning mechanism for a charging roller used in the charging device.

In addition to a configuration using an image forming unit for a single color image, an image forming apparatus using an electrophotographic system can receive a multicolor image such as a full color image by using an image forming unit capable of forming a multi-color image. There are configurations to form.
The image forming unit is provided with a charging device for uniformly charging the latent image carrier. However, the charging member used in the charging device is configured so as to be in contact with the surface of the latent image carrier or in close proximity. A configuration that maintains a contact state is known.

In the contact charging method in which charging is performed while bringing a charging member into contact with the surface of the latent image carrier, a configuration is known in which a charging roller in which an elastic layer made of conductive rubber is provided on a core metal is used as the charging member.
At the time of charging by the charging member having the above configuration, the surface of the latent image carrier can be charged to a predetermined potential by applying a bias to the core of the charging roller as the charging member.

However, in the contact charging method, there are many opportunities for transfer of untransferred toner remaining on the latent image carrier, abrasion powder that peels off from the roller surface as a charging member and the photosensitive layer surface of the latent image carrier, and these foreign matters are transferred. It may adhere to the surface of the charging roller.
If the foreign matter remains attached to the surface of the charging roller, the resistance distribution on the surface of the charging roller changes, leading to a phenomenon in which the charged potential on the surface of the latent image carrier becomes uneven. As a result, there is a possibility that an abnormal image such as image density unevenness may occur because uniform charging on the surface of the latent image carrier cannot be obtained.

Conventionally, as a configuration for preventing foreign matter from adhering to the surface of the charging roller, which is a charging member, a large number of irregularities are formed on the surface of the charging roller used for the electric member to contact the photoreceptor, which is a latent image carrier. The structure which makes small is proposed (for example, patent document 1). In this configuration, the contact area can be reduced to reduce the chance of foreign matter transfer due to contact with the photosensitive member, so that contamination on the surface of the charging roller can be reduced. In addition, there is an advantage that stable charging can be performed by appropriately distributing the gap roller at the contact portion in the axial direction due to the uneven shape of the charging roller.
However, this configuration has a problem in that it is difficult to remove the foreign matter transferred to the charging roller because the foreign matter that has once entered the concavo-convex portion is difficult to be removed, and it is difficult to remove dirt.

Therefore, it is conceivable to provide a cleaning member that can come into contact with the charging roller and scrape off foreign matter.
For example, a configuration may be used in which a roller-shaped cleaning member is brought into contact with the charging roller so that the charging roller rotates.
However, in this configuration, since it follows the charging roller at a constant speed, it does not have a sufficient effect of scraping off foreign matter, and dirt accumulates over time on the charging roller, resulting in a charging characteristic on the surface of the charging roller. It is not constant. As a result, there remains a problem that an abnormal image in which uneven charging occurs and uneven density is obtained.

As the cleaning member, a fixed blade-like structure may be used instead of a roller.
In this configuration, a speed difference is generated between the charging roller and the cleaning member, so that an effect of scraping off the foreign matter on the charging roller can be obtained efficiently.
However, although the cleaning capability is high between the initial stages, the damage to the charging roller surface increases as the blade tip rubs against the charging roller surface over time. Further, the scraping ability is reduced due to wear of the cleaning member. Thereby, maintenance of the cleaning capability over a long period cannot be expected.

As a configuration for preventing the scraping ability of the cleaning member from decreasing with time, a configuration in which the cleaning member is brought into contact with the charging roller only at a predetermined time has been proposed (for example, Patent Document 2).
In this configuration, the cleaning member is brought into contact with the charging roller during non-image formation, and the cleaning member is separated from the charging roller during image formation.

  In order to effectively remove foreign matter from the charging roller, the bias electric field direction between the charging roller and the cleaning member is switched between image formation and non-image formation, and the rotation speed of the cleaning member is changed. It has been proposed (for example, Patent Document 3).

  Furthermore, as a configuration for enhancing the foreign matter removal action from the charging roller, a configuration is proposed in which the cleaning member on the roller is brought into contact with the charging roller, and the scraping action is enhanced by variably controlling the rotation speed of the cleaning member. (For example, Patent Document 4).

However, the configurations disclosed in the above patent documents have the following problems.
With the configuration disclosed in Patent Document 2, it is difficult to obtain a uniform contact because there is a possibility that the contact / separation mechanism of the cleaning member to the charging roller becomes complicated.
In addition, since the location where the cleaning member contacts the charging roller is always the same, dirt is accumulated at the contact location, resulting in a decrease in cleaning capability over time and the removal of suddenly generated foreign matter. There is a bug.

  In the configuration disclosed in Patent Document 3, bias control and rotation speed control and a plurality of control items are required, and thus control may be complicated.

In the configuration disclosed in Patent Document 4, the control mechanism is complicated because control for changing the amount of cleaning member biting into the charging roller and control for changing the rotation speed of the cleaning member are performed in the monochrome mode and the full color mode. It becomes. In addition, since no consideration is given to the change in the amount of wear due to the difference in the amount of bite, the scraping ability of foreign matter tends to decrease with time, and damage to the charging roller tends to increase at the initial stage.
In addition, since the charging roller and the cleaning member are independently controlled for rotation, the configuration of the drive system may be complicated and large.
In addition, since the charging roller and the cleaning member that are independently controlled to rotate are supported by the same bearing member, in order to maintain the contact between the two in consideration of the tolerance at each support position, the charging roller and the cleaning member are predetermined to each other. The relationship is closer than the condition. This tends to increase the contact pressure of the cleaning member. As a result, the cleaning member may come into strong contact with the charging roller, which may increase the damage to the charging roller surface.

  In view of problems in cleaning for charging members, the present invention prevents the deterioration of charging characteristics by maintaining the cleaning of the charging members with a simple configuration without causing the structure to be complicated or large. An object of the present invention is to provide a charging device having a configuration for preventing image generation.

  In order to achieve this object, the present invention provides a charging member used for uniformly charging the surface of a latent image carrier and a cleaning member capable of removing foreign substances attached to the surface of the charging member in contact with the surface of the charging member. The cleaning member can select a driven rotation state with respect to the charging member in each of a first mode and a second mode by changing a contact pressure with respect to the charging member. The second mode is a charging device in which a relationship is set such that a linear speed ratio of the cleaning member to the charging member is larger than that of the first mode.

  According to the present invention, it is possible to reduce the damage to the charging member and maintain the cleaning without using a complicated structure only by selecting two modes, and to prevent the charging characteristics from deteriorating. In particular, since each mode only uses a change in the contact pressure of the cleaning member with respect to the charging member, it is possible to perform cleaning in conjunction with the operating state of the charging member.

1 is a schematic diagram for explaining a configuration of an image forming apparatus using a charging device according to an embodiment of the present invention. FIG. 2 is a schematic diagram for explaining a configuration of a process cartridge used in an image forming unit of the image forming apparatus shown in FIG. 1. FIG. 3 is a diagram for explaining a layer structure of a photoconductor equipped in the process cartridge shown in FIG. 2. FIG. 3 is a diagram showing a comparison with a conventional example regarding a cleaning blade used in a cleaning device provided in the process cartridge shown in FIG. 2. FIG. 3 is a diagram illustrating an example of a configuration of a charging roller used in the process cartridge illustrated in FIG. 2. FIG. 6 is a view showing a modification of the main part of the charging roller shown in FIG. 5. FIG. 3 is a view for explaining a characteristic part of a charging device used in the process cartridge shown in FIG. 2. It is a perspective view of the characteristic part shown in FIG. It is a diagram for demonstrating the relationship between the linear speed ratio of the charging roller and the cleaning member obtained by the characteristic part shown in FIG. 7, and the applied pressure of the cleaning member. It is a block diagram for demonstrating the structure of the control part used in order to set the relationship shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to illustrated embodiments.
FIG. 1 is a diagram illustrating a configuration of a printer 100 that is one of image forming apparatuses using a charging device according to an embodiment of the present invention.
The printer 100 shown in the figure includes a configuration capable of forming a full-color image by including a plurality of color image forming units. That is, the printer 100 includes an image forming unit 120 including a plurality of image forming units, an intermediate transfer device 160, and a paper feeding unit 130 as main parts.
In the image forming unit 120, process cartridges 121 constituting a plurality of image forming units are arranged along the extending direction of an intermediate transfer belt 162 used in an intermediate transfer device 160 described later. Note that the subscripts Y, C, M, and K attached to the numerals shown in the figure mean yellow, cyan, magenta, and black, and the process cartridge 121 of each image forming unit has a different color image. It shows that it can be formed.
Details of the process cartridge 121 will be described later with reference to FIG.

The intermediate transfer device 160 is provided with an intermediate transfer belt 162 that is wound around a plurality of support rollers and is movable in the direction of the arrow shown in the drawing.
A primary transfer roller 161 that sequentially transfers an image formed on the photoreceptor 10 provided in each image forming unit to the intermediate transfer belt 162 at a position facing each image forming unit in the extended portion of the intermediate transfer belt 162. Has been placed.
A secondary transfer roller 165 for transferring the superimposed image transferred to the intermediate transfer belt 162 onto a transfer sheet used as a recording medium is disposed on one side of the intermediate transfer belt in the extending direction.
The intermediate transfer belt 162 can move in the direction indicated by the arrow using one of the support rollers as a drive roller, and moves in synchronization with the movement of the photoconductor 10 provided in each image forming unit.
The primary transfer roller 161 is disposed to face the photoreceptor 10 provided in each image forming unit with the intermediate transfer belt 162 interposed therebetween, and a toner image formed on the photoreceptor 10 is placed on the intermediate transfer belt 162. Transcript. The primary transfer roller 161 is configured to contact the intermediate transfer belt 162 with a weak pressure against the photoreceptor 10.

The intermediate transfer belt 162 is in contact with or separated from the photoreceptors 10 (Y, C, M) other than the image forming unit that forms a black (K) color image among the image forming units by an unshown contact / separation mechanism. can do. Accordingly, when forming a single color image of only black (K), it is possible to move away from the photoconductor 10 of the image forming unit that forms an image of another color.
Regarding the contact / separation of the intermediate transfer belt 162, a mechanism for contacting / separating the primary transfer roller 161 or a mechanism for swinging the other support roller side with a support roller positioned on the black (K) image forming unit side as a swing fulcrum. Etc. are used.

  The intermediate transfer device 160 has a unit structure or the like, and is configured to be detachable from the main body of the printer 100. Specifically, the front cover (not shown) on the front side of the paper in FIG. 1 covering the image forming unit 120 of the printer 100 is opened to take out to the outside. Is executed.

In FIG. 1, reference numeral 167 denotes a belt cleaning device that removes untransferred toner remaining on the intermediate transfer belt 162 after the batch transfer by the secondary transfer roller 165 is completed. The belt cleaning device 167 is configured to be attachable to and detachable from the apparatus main body together with the intermediate transfer belt 162. Further, the untransferred toner collected by the belt cleaning device 167 can be returned to a developing device 50 in a process cartridge, which will be described later, or transported toward a waste toner tank (not shown).
In FIG. 1, reference numerals 159 (Y, C, M, and K) indicate toner cartridges that store replenishment toner for the developing device 60. Toner is supplied from the toner cartridge 159 when the toner density in the developing device 60 decreases.

  In FIG. 1, reference numeral 140 denotes a writing apparatus that irradiates the photosensitive member 10 with writing light for each image forming unit. The writing device 140 forms an electrostatic latent image on the photosensitive member 10 by irradiating the photosensitive member 10 with writing light corresponding to image information transmitted from a control unit (not shown).

In FIG. 1, a paper feeding unit 130 is disposed below the writing device 140.
The paper feed unit 130 includes a plurality of paper feed cassettes 131, and transfer paper is fed from each paper feed cassette 131 toward the conveyance path by a feed roller 132. The transfer sheet fed to the transport path is transported toward the position of the secondary transfer roller 165 after the registration timing is set by the registration rollers 133 arranged in the transport path, and is carried on the intermediate transfer belt 162. The superimposed images are transferred at once.
The transfer paper after the batch transfer is discharged toward the paper discharge tray via the paper discharge roller 90.

FIG. 2 is a diagram showing a configuration of the process cartridge 121 used for each image forming unit.
Since the configuration of the process cartridge 121 is the same in each image forming unit, in the following description, the symbols Y, C, M, and K that indicate the type of color are omitted.
In the figure, a photosensitive member 10 as a latent image carrier is disposed in a process cartridge 121, and a charging device 40 that executes image forming processing along the moving direction of the photosensitive member 10 around the photosensitive member 10. A developing device 50 and a cleaning device 30 are arranged.
The charging device 40 is a device used to uniformly charge the surface of the latent image carrier, that is, the surface of the photosensitive member, and a charging roller 41 is used as a main part.

In the case of this embodiment, the photosensitive drum 10 uses a rotatable drum, has at least a photosensitive layer on a conductive support, and inorganic fine particles are dispersed on the surface thereof.
Hereinafter, each layer structure of the photoconductor 10 (hereinafter, the photoconductor may be expressed as an image carrier for convenience) will be described.
FIG. 3A shows an example in which a photosensitive layer 92 containing inorganic fine particles is provided in the vicinity of the surface on a conductive support 91. FIG. 3B shows an example in which a surface layer 93 containing a photosensitive layer 92 and inorganic fine particles is provided on a conductive support 91. FIG. 3C shows an example in which a charge generation layer 921, a photosensitive layer 92 in which a charge transport layer 922 is stacked, and a surface layer 93 containing inorganic fine particles are provided on a conductive support 91. FIG. 3D shows an example in which an undercoat layer 94 is provided on a conductive support 91, a photosensitive layer 92 in which a charge generation layer 921, a charge transport layer 922 are stacked, and a surface layer 93 containing inorganic fine particles are provided. Show.

The photoreceptor 10 shown in FIG. 3 only needs to have a structure having at least the photosensitive layer 92 and the surface layer 93 on the conductive support 91, and other layers and the like may be arbitrarily combined.
As the conductive support 91, a material having a volume resistance of 1010 Ω · cm or less, for example, the following material is used.
A metal or metal oxide such as aluminum, nickel, chromium, nichrome, copper, gold, silver or platinum, or metal oxide such as tin oxide or indium oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, Alternatively, a plate made of aluminum, an aluminum alloy, nickel, stainless steel, or the like, and a tube subjected to surface treatment such as cutting, superfinishing, polishing, or the like after being formed into a raw pipe by a method such as extrusion or drawing can be used.
Further, an endless nickel belt and an endless stainless steel belt disclosed in Patent Document 4 can also be used as the conductive support 91.

In addition to this, as the configuration of the conductive support 91, it is also possible to use a conductive powder dispersed on an appropriate binder resin and coated on the surface. The conductive powder used in this case is carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, silver, or metal oxide powder such as conductive tin oxide, ITO, etc. Examples include the body.
The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin.

Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support 91 of the present invention.

Next, the photosensitive layer 92 will be described.
The photosensitive layer 92 may be a single layer or a stacked layer. For convenience of explanation, the photosensitive layer 92 is first described from the case where it is composed of the charge generation layer 921 and the charge transport layer 922 (configuration shown in FIG. 3C).
The charge generation layer 921 is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer 921, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycycles. Examples thereof include compounds, squalic acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, and azulenium salt dyes. These charge generation materials may be used alone or in combination of two or more.

In this embodiment, in particular, azo pigments and / or phthalocyanine pigments are effectively used.
In particular, an azo pigment represented by the following chemical structural formula (1) and titanyl phthalocyanine (particularly, a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.514Å) of CuKα is at least 27) And titanyl phthalocyanine having a maximum diffraction peak at 2 ° can be used effectively.
The charge generation layer 921 is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto the conductive support 91 and dried. It is formed by.
As the binder resin used for the charge generation layer 921 as necessary, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N -Vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, etc. Can be mentioned. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.

Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. In particular, ketone solvents, ester solvents, and ether solvents are preferably used.
As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used.
The thickness of the charge generation layer 921 is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.
The charge transport layer 922 can be formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer 921.
Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
Charge transport materials include hole transport materials and electron transport materials.

Examples of the charge transport material include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol Examples thereof include thermoplastic or thermosetting resins such as resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin.
The thickness of the charge transport layer 922 is preferably 25 μm or less from the viewpoint of resolution and responsiveness.
Regarding the lower limit, although it differs depending on the system to be used (particularly the charging potential), it is preferably 5 μm or more.
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone or the like is used.

In the case of the image carrier in this embodiment, a plasticizer or a leveling agent may be added to the charge transport layer 922.
As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin.
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 0 to 0 with respect to the binder resin. 1% by weight is suitable.
In the case where the charge transport layer 922 is an outermost layer, the charge transport layer 922 contains inorganic fine particles. Inorganic fine particles include metal powders such as copper, tin, aluminum, indium, silicon oxide, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin Metal oxides such as indium oxide, and inorganic materials such as potassium titanate. In particular, metal oxides are good, and silicon oxide, aluminum oxide, titanium oxide and the like can be used effectively.
The average primary particle size of the inorganic fine particles is preferably 0.01 to 0.5 μm from the viewpoint of the light transmittance and wear resistance of the surface layer 93.
When the average primary particle size of the inorganic fine particles is 0.01 μm or less, it causes a decrease in wear resistance and a dispersibility. Or toner filming may occur.
The higher the amount of inorganic fine particles added, the better the wear resistance and the better. However, when the amount is too high, the residual potential increases and the write light transmittance of the protective layer decreases, which may cause side effects. Therefore, it is generally 30% by weight or less, preferably 20% by weight or less, based on the total solid content.
The lower limit is usually 3% by weight.

Further, these inorganic fine particles can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the inorganic fine particles.
A decrease in the dispersibility of inorganic fine particles not only increases the residual potential, but also decreases the transparency of the coating film, the occurrence of coating film defects, and a decrease in wear resistance. It can develop into a big problem to hinder.

Next, the case where the photosensitive layer 92 has a single layer structure will be described.
An image carrier in which the above-described charge generating material is dispersed in a binder resin can be used.
The single-layer photosensitive layer 92 can be formed by dissolving or dispersing a charge generation material, a charge transport material, and a binder resin in an appropriate solvent, and applying and drying the solution.
Further, when the single photosensitive layer 92 becomes the surface layer 93, the inorganic fine particles are contained. Further, the photosensitive layer 92 may be a function separation type to which the above-described charge transport material is added, and can be used satisfactorily.
Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, the binder resin previously mentioned in the charge transport layer 922 may be used as it is, or the binder resin mentioned in the charge generation layer may be mixed and used.
The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight.
The single-layer photosensitive layer 92 is formed by immersing a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transporting material, if necessary, using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane with a disperser or the like. It can be formed by spray coating or bead coating. The film thickness of the single photosensitive layer 92 is suitably about 5 to 25 μm.

In the image carrier in this embodiment, an undercoat layer 94 can be provided between the conductive support 91 and the photosensitive layer 92.
The undercoat layer 94 generally contains a resin as a main component. However, considering that the photosensitive layer 92 is applied with a solvent thereon, these resins are resins having high solvent resistance with respect to general organic solvents. It is desirable.
Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin.
Further, in order to prevent moire and reduce residual potential, the undercoat layer 94 may be added with fine powder pigments of metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like. Good.
The undercoat layer 94 can be formed using an appropriate solvent and coating method like the photosensitive layer 92 described above.
Further, in this embodiment, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer 94.
In addition, the undercoat layer 94, and those in which a Al2O3 with anodic oxidation, polyparaxylylene (parylene) or the like of the organic substances and _{SiO 2, SnO 2, TiO 2} , ITO, an inorganic material such as CeO ₂ vacuum Those provided by the thin film preparation method can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer 94 is suitably 0 to 5 μm.

In the image carrier in this embodiment, a surface layer 93 containing inorganic fine particles can be provided on the outermost surface of the photosensitive layer 92.
The surface layer 93 is composed of at least inorganic fine particles and a binder resin. As the binder resin, a thermoplastic resin such as polyarylate resin or polycarbonate resin, or a crosslinked resin such as urethane resin or phenol resin is used.
As the fine particles, organic fine particles and inorganic fine particles are used. Examples of the organic fine particles include fluorine-containing resin fine particles and carbon-based fine particles. Metal powder such as copper, tin, aluminum, indium, silicon oxide, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, antimony-doped tin oxide, tin-doped indium oxide, etc. Inorganic materials such as metal oxide and potassium titanate can be mentioned. In particular, metal oxides are good, and silicon oxide, aluminum oxide, titanium oxide and the like can be used effectively.
The average primary particle size of the inorganic fine particles is preferably 0.01 to 0.5 μm from the viewpoint of the light transmittance and wear resistance of the surface layer 93.
When the average primary particle size of the inorganic fine particles is 0.01 μm or less, it causes a decrease in wear resistance and a dispersibility. Or toner filming may occur.
The higher the concentration of the inorganic fine particles in the surface layer 93, the higher the wear resistance and the better. .
Therefore, it is approximately 50% by weight or less, preferably 30% by weight or less, based on the total solid content.
The lower limit is usually 5% by weight.
Further, these inorganic fine particles can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the inorganic fine particles.
A decrease in the dispersibility of inorganic fine particles not only increases the residual potential, but also decreases the transparency of the coating film, the occurrence of coating film defects, and a decrease in wear resistance. It can develop into a big problem to hinder.

As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the inorganic fine particles is preferable.
For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixing treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of dispersibility of inorganic fine particles and image blur.
The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent.
The surface treatment amount varies depending on the average primary particle size of the inorganic fine particles used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%.

If the surface treatment amount is less than this, the dispersion effect of the inorganic fine particles cannot be obtained, and if it is too much, the residual potential is significantly increased.
These inorganic fine particles-materials are used alone or in combination of two or more. The thickness of the surface layer 93 is preferably in the range of 1.0 to 8.0 μm.
An image carrier that is used repeatedly over a long period of time is mechanically durable and hardly wears.
However, ozone, NOx gas, and the like are generated from the charging member or the like in the actual machine and adhere to the surface of the image carrier. If these deposits are present, image flow occurs.
In order to prevent this image flow, it is necessary to wear the photosensitive layer 92 at a certain speed or higher.
For that purpose, it is preferable that the surface layer 93 has a film thickness of at least 1.0 μm or more in consideration of long-term repeated use.

Further, when the thickness of the surface layer 93 is larger than 8.0 μm, it is considered that the residual potential is increased and the fine dot reproducibility is decreased.
These inorganic fine particles-materials can be dispersed by using an appropriate disperser.
The average particle size of the inorganic fine particles in the dispersion is 1 μm or less, preferably 0.5 μm or less from the viewpoint of the transmittance of the surface layer 93.
As a method of providing the surface layer 93 on the photosensitive layer 92, a dip coating method, a ring coating method, a spray coating method, or the like is used.
Among these, a general method for forming the surface layer 93 is to form a coating film by ejecting paint from a nozzle having a minute opening and depositing fine droplets generated by atomization on the photosensitive layer 92. A spray coating method is used.
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone or the like is used.
The surface layer 93 may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport layer can be used.
When a low molecular charge transport material is used as the charge transport material, it may have a concentration gradient in the surface layer 93.
For the surface layer 93, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used.

The surface layer 93 composed of these polymer charge transport materials is excellent in wear resistance.
A known material can be used as the polymer charge transport material, but at least one polymer selected from polycarbonate, polyurethane, polyester, and polyether is preferable. In particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferable.
It is preferable that the image carrier surface layer 93 has a Martens hardness of 190 N / mm 2 or more and an elastic work rate (We / Wt value) of 37.0% or more. The Martens hardness and the elastic power increased here are measured under the following conditions.
Evaluation device: Fisherscope H-100
Test method: Load unloading repetition (one time) test Indenter: Micro Vickers indenter Maximum load: 9.8 mN
Load (unloading) time: 30 seconds Holding time: 5 seconds
When the Martens hardness is less than 190 N / mm 2, there is a problem that the toner adheres to the surface of the photoreceptor. Also, when the elastic power (We / Wt value) is less than 37.0%, there is a problem that the wear speed of the photoconductor changes and wear unevenness occurs, for example, when the image area ratio changes in the photoconductor axis direction. Arise.
For this reason, hardness and elastic work rate are controlled by the addition amount of inorganic fine particles and the resin type. Resins such as polycarbonate and polyarylate are improved in hardness and elastic power by incorporating a rigid structure into the resin skeleton. Further, by adopting the polymer charge transport material, the hardness and elastic power are improved.
Fine irregularities are formed on the surface of the photoreceptor by the addition of inorganic fine particles. For this reason, the adhesion force to the photosensitive member is reduced, and filming of the toner base material and the external additive to the photosensitive member is less likely to occur. The surface roughness of the photoreceptor is preferably about Rz = 0.3 to 1.0 μm. The surface roughness is measured with Surfcom 1400D (manufactured by Tokyo Seimitsu).

Returning to FIG. 2, the developing device 50 can perform visible image processing on the electrostatic latent image on the photoconductor 10 by supplying toner to the surface of the photoconductor 10.
The developing device 50 is provided with a developing tank capable of containing a developer, and a developing roller 51 capable of carrying the developer is disposed inside the developing tank so as to face the photoreceptor.
In the developing tank, the supply screw 52 supplied while stirring and conveying the developer toward the developing roller 51 and the developer in the developing tank are stirred and conveyed, and the replenished toner is mixed and stirred in the developer. A screw 53 is arranged.
In the developing device 50, the developer supplied from the supply roller 52 to the developing roller 51 is supplied toward the photoconductor 10 after the layer thickness is regulated by a doctor blade (not shown). The developer causes toner to be attracted to the electrostatic latent image by the electrostatic attraction force from the electrostatic latent image and the developing bias applied to the developing roller 50 to make the electrostatic latent image visible.

The developing device 50 uses a toner having a low glass transition point that can lower the fixing temperature.
Hereinafter, the toner characteristics will be described.
First, the reason why a toner having a low glass transition point (low Tg) compatible with low-temperature fixing is used as the toner used in the developing device 50 shown in this embodiment will be described.
The reason for this is to reduce the energy required for fixing, that is, to shorten the warm-up time in the fixing device and to reduce the power consumption associated therewith for the purpose of saving energy. Hereinafter, it is prefaced that the glass transition point may be expressed as Tg, and that the low-temperature fixing toner may be referred to as low Tg toner.

Specifically, in the 1999 International Energy Agency (IEA) Demand-side-Management (DSM) program, there is a technology procurement project for next-generation copiers. Has been. That is, for a copying machine of 30 cpm or more, the standby time is within 10 seconds, and power consumption during standby is 10 to 30 watts or less (depending on the copying speed). Thus, it is required to achieve dramatic energy savings as compared to conventional copying machines.
One way to achieve this requirement is to reduce the heat capacity of a fixing member such as a heating roller to improve the temperature responsiveness of the toner, but it is not fully satisfactory.
In order to achieve the above requirement and minimize the waiting time, it is considered to be an essential technical achievement matter to lower the fixing temperature of the toner itself and lower the toner fixing temperature when it can be used.

However, when the toner is fixed at a low temperature in this way, there is a problem that it becomes difficult to secure a fixing temperature range (hot offset resistance) and maintain heat-resistant storage stability.
As a study for achieving both low-temperature fixability and hot offset resistance of the toner, it is conceivable to use a polyester resin as the binder resin for the toner.
In order to maintain better low-temperature fixability, it is necessary to design a resin that further lowers the molecular weight of the binder resin and emphasizes sharp melt properties. Will occur.

In addition, as a toner excellent in all of low-temperature fixability, hot offset resistance, and heat-resistant storage stability, a production process including a high molecular weight process in which an isocyanate group-containing polyester prepolymer is subjected to a polyaddition reaction with an amine in an organic solvent and an aqueous medium. What is obtained by the method has been proposed (for example, Japanese Patent Laid-Open No. 2002-287400, Japanese Patent Laid-Open No. 2002-351143, etc. are provided as references).
However, it has been found that, even in the above production method, the sharp melt property of the polyester resin as the base resin is insufficient to satisfy the low-temperature fixability of the toner.

  In view of the background as described above, the toner used in this embodiment is an electrostatic image developing toner composed of at least a binder resin and a colorant. The binder resin is a toner including a modified polyester resin and a polyester resin that satisfies the following conditions (1) to (4).

(1) The glass transition point (Tg) is 39 to 65 ° C. In this embodiment, a toner whose glass point transfer is in the range of 40 to 60 ° C. is targeted.
(2) The value (Mw / Tg) obtained by dividing the weight-average molecular weight (Mw) of the THF-soluble matter by the glass transition point (Tg / ° C.) is 40 to 120.
(3) An alkylene having a benzene ring skeleton and a 1,4-cyclohexylene skeleton in a molar ratio (benzene ring skeleton / 1,4-cyclohexylene skeleton) of 2.0 to 15.0 and having ester bonds at both ends with the benzene skeleton The molar ratio of the skeleton (benzene skeleton / both terminal ester bond alkylene skeleton) is 3.0 or more.
(4) The THF-soluble component has a weight average molecular weight of 2,000 to 7,800.
The polyester resin used for the binder resin has a tendency that the Mw rapidly decreases as Tg is decreased from 65 ° C., and it is difficult to satisfy all of the low-temperature fixability, hot offset resistance, and heat storage stability. there were.
When the Tg of the polyester resin is less than 39 ° C., the heat resistant storage stability cannot be improved no matter how much Mw is adjusted.
Therefore, Tg is set to 39 to 65 ° C. and the Mw / Tg value is set to 40 to 120 as a range in which the physical properties of the toner can be balanced. When the value of Mw / Tg is within the above range, the polyester resin has a Tg capable of maintaining heat-resistant storage stability, and also has a low molecular weight, further improving the low-temperature fixability of the toner, and heat-resistant storage stability. Maintenance is possible. Mw and Tg are obtained by the following measuring method, and the unit of Tg in the value of Mw / Tg is ° C.

The glass transition point (Tg) is measured with a Rigaku THRMOFLEX TG8110 manufactured by Rigaku Corporation under a temperature increase rate of 10 ° C./min.
The molecular weight is measured by GPC (gel permeation chromatography) as follows. Specifically, the column was stabilized in a heat chamber at 40 ° C., and THF as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min to prepare a sample concentration of 0.05 to 0.6% by weight. Measurement is performed by injecting 50 to 200 μl of a THF sample solution of the resin.
In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value of the prepared calibration curve and the count using several types of monodisperse polystyrene standard samples.
As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Or the molecular weight of Toyo Soda Kogyo Co., Ltd. 6x102, 2.1x103, 4x103, 1.75x104, 5.1x104, 1.1x105, 3.9x105,8. 6 × 105, 2 × 106, 4.48 × 106 are used. It is appropriate to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

As the polyester resin satisfying the above conditions, those having a chemical structure having the following characteristics are preferable.
The molar ratio of the benzene ring skeleton and 1,4-cyclohexylene skeleton of the polyester resin (benzene ring skeleton / 1,4-cyclohexylene skeleton) is 2.0 to 15.0. The molar ratio (benzene skeleton / both terminal ester bond alkylene skeleton) of the alkylene skeleton is 3.0 or more.
The glass transition point (Tg) of the polyester resin is mainly governed by its chemical structure, and the Tg tends to increase as the benzene ring skeleton continues and as the content increases.
Further, the longer the alkylene skeleton and the higher the content, the lower the Tg.
Therefore, when the content of the benzene ring skeleton is large, the hot offset resistance and the heat-resistant storage stability are improved, but it is disadvantageous for low-temperature fixability. It adversely affects hot offset resistance and heat resistant storage stability.
On the other hand, by appropriately containing the 1,4-cyclohexylene skeleton, the weight average molecular weight of the resin can be adjusted while maintaining the Tg, and the low-temperature fixability can be further improved.
Therefore, the ranges of the molar ratio (benzene ring skeleton / 1,4-cyclohexylene skeleton) and molar ratio (benzene skeleton / both terminal ester bond alkylene skeleton) are defined as described above.
When the molar ratio (benzene ring skeleton / 1,4-cyclohexylene skeleton) is less than 2.0, the polyester resin becomes brittle and the durability of the toner itself is lost.
If the molar ratio (benzene ring skeleton / 1,4-cyclohexylene skeleton) is greater than 15.0, it will be difficult to achieve a low molecular weight while maintaining the glass transition point, and low-temperature fixability will not be exhibited.
On the other hand, if the molar ratio (benzene skeleton / both terminal ester bond alkylene skeleton) is less than 3.0, it is difficult to maintain heat-resistant storage stability.

  The molar ratio (benzene ring skeleton / 1,4-cyclohexylene skeleton) and molar ratio (benzene skeleton / both terminal ester-bonded alkylene skeleton) are the composition ratios of the polyvalent carboxylic acid and polyhydric alcohol used as the raw material of the resin. Can be calculated. It can also be calculated by 1H-NMR (nuclear magnetic resonance) measurement of the produced resin.

In order to have low-temperature fixability and hot offset resistance and maintain heat-resistant storage stability, it is important to adjust the weight average molecular weight (Mw) of the polyester resin. It is preferable to design Mw of 2,000 to 7,800.
When the Mw is less than 2,000, the oligomer component increases, so that the heat-resistant storage stability is deteriorated even when the chemical structure is controlled as shown above. When the Mw exceeds 7,800, the melting temperature is increased and the low-temperature fixability is deteriorated. It is to do.

  In addition, by setting the acid value of the polyester resin to 1.0 to 50.0 KOHmg / g, toner properties such as low-temperature fixability, hot offset resistance, heat-resistant storage stability, and charging stability can be improved. Is possible.

On the other hand, the low Tg toner capable of low-temperature fixing used in this embodiment uses the above polyester resin as a binder resin and also has a heavy component having a site capable of reacting with a compound having an active hydrogen group, which will be described in detail later. A coalescence (hereinafter referred to as “prepolymer”) can be mixed and produced.
By mixing this prepolymer with a compound having an active hydrogen group, an elongation or a crosslinking reaction can be performed in the toner production process, and the above-described toner characteristics can be improved.
Here, when the acid value of the polyester resin exceeds 50.0 KOHmg / g, the prepolymer elongation or crosslinking reaction becomes insufficient, and the hot offset resistance is affected. If it is less than 1.0 KOHmg / g, the prepolymer is likely to elongate or crosslink, which causes a problem in production stability.

In addition, the measuring method of the acid value of a polyester resin is based on the method based on JISK0070.
However, when the sample does not dissolve, a solvent such as dioxane or THF is used as the solvent.

In this example, it was found from further investigation that the acid value of the toner as well as the acid value of the polyester resin is important for low-temperature fixability and hot offset resistance.
The acid value of the toner is preferably 0.5 to 40.0 KOH mg / g.
This is because when the acid value of the toner exceeds 40.0 KOHmg / g, the prepolymer elongation or crosslinking reaction becomes insufficient, and the hot offset resistance is affected. Moreover, if it is less than 0.5 KOHmg / g, the elongation or crosslinking reaction of the prepolymer is likely to proceed, causing a problem in production stability. The acid value of the toner can be measured in the same manner as the acid value of the polyester resin.

The glass transition point of the toner is preferably 40 to 60 ° C. in order to obtain low temperature fixability, heat resistant storage stability and high durability.
If the glass transition point is less than 40 ° C., toner blocking and filming on the photoreceptor are likely to occur in the developing machine, and if it exceeds 60 ° C., the low-temperature fixability tends to deteriorate.
The measurement of the glass transition point of the toner can be performed in the same manner as the glass transition point of the polyester resin.

The volume average particle diameter (Dv) of the low Tg toner used in this embodiment is preferably 3 to 8 μm, and the ratio (Dv / Dn) to the number average particle diameter (Dn) is 1.00. More preferably, it is in the range of ˜1.25.
By defining Dv / Dn in this way, it is possible to obtain a toner with high resolution and high image quality.
In order to obtain a higher quality image, it is necessary to set Dv to 3 to 7 μm, Dv / Dn to 1.00 to 1.20, and particles 3 μm or less to 1% to 10% by number. Good. More preferably, Dv is 3 to 6 μm and Dv / Dn is 1.00 to 1.15.
Such a toner is excellent in all of heat-resistant storage stability, low-temperature fixability, and hot offset resistance, and particularly excellent in image gloss when used in a full-color copying machine.
Furthermore, in the two-component developer, even if the toner balance for a long period of time is performed, the toner particle size fluctuation in the developer is reduced, and good and stable developability can be achieved even with long-term stirring in the developing device. can get.

  For the average particle size and particle size distribution of the toner, a Coulter Counter TA-II type was used, and an interface (manufactured by Nikka Giken) that outputs the number distribution and volume distribution was connected to a PC 9801 personal computer (manufactured by NEC). It was measured.

The low Tg toner for low-temperature fixing in the present invention preferably has an average circularity of 0.92 to 1.00.
Thereby, a high-definition image with an appropriate image density can be formed with good reproducibility.
If the average circularity is less than 0.92, it is difficult to obtain a satisfactory transferability and a high-quality image free from dust. The average circularity of the toner can be measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.).
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 obtained by performing dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

The low Tg toner used in this embodiment preferably has a BET specific surface area of 1.0 to 6.0 (m ² / g).
If the BET specific surface area is less than 1.0 (m ² / g), the image quality deteriorates due to the presence of coarse particles and inclusion of additives.
On the other hand, if it exceeds 6.0 (m ² / g), the image quality deteriorates due to the presence of fine particles, the emergence of additives, and surface irregularities.
The measurement of the BET specific surface area of the toner is performed using a device that can comply with JIS standards (Z8830 and R1626) such as NOVA series manufactured by Yuasa Ionics.

In addition, the material constituting the low Tg toner used in this embodiment will be described.
The polyester resin is obtained by polycondensation of a polyhydric alcohol (PO) and a polyvalent carboxylic acid (PC).
Examples of the polyhydric alcohol compound (PO) include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). (DIO) alone or a mixture of (DIO) and a small amount of (TO) preferable.
Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol, etc.) 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 these, it is particularly preferable to use together an alkylene oxide having 2 to 12 carbon atoms, an alicyclic diol, or an alkylene oxide adduct of bisphenols.
The trihydric or higher polyhydric alcohol (TO) 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 polyvalent carboxylic acid (PC) include divalent carboxylic acid (DIC) and trivalent or higher polyvalent carboxylic acid (TC). (DIC) alone and (DIC) with a small amount of (TC) Mixtures are preferred.
Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid).
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 polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).
In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

The prepolymer contained in the Tg toner used in this embodiment is preferably a polyester prepolymer (A) containing an isocyanate group, and is a polycondensate of a polyhydric alcohol (PO) and a polycarboxylic acid (PC) and It can be obtained by reacting with a polyester having an active hydrogen group and further with a polyvalent isocyanate (PIC).
In this case, examples of the active hydrogen group of the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

  Examples of the polyhydric alcohol (PO) include the same compounds as those used in the production of the polyester resin. Of these, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols. Particularly preferred are alkylene oxide adducts of bisphenols and combinations thereof with alkylene glycols having 2 to 12 carbon atoms.

  Examples of the polyvalent carboxylic acid (PC) include the same compounds as those used in the production of the polyester resin. Among these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatics having 8 to 20 carbon atoms. Group dicarboxylic acid.

  The ratio of the polyhydric alcohol (PO) to the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Is 1.5 / 1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  Examples of polyisocyanates (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; And those blocked with caprolactam; and combinations of two or more of these.

When the polyester-based prepolymer (A) having an isocyanate group is obtained, the ratio of the polyvalent isocyanate (PIC) to the polyester-based resin (PE) having active hydrogen is determined by the ratio of the isocyanate group [NCO] and the hydroxyl group of the polyester having a hydroxyl group. The equivalent ratio [NCO] / [OH] to [OH] is usually 5/1 to 1/1, preferably 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 /. 1.
The content of the polyvalent isocyanate (PIC) 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.

Next, polyamines and / or amines having active hydrogen groups are used as the amines (B), which are compounds having active hydrogen groups, which are reacted with the prepolymer (A).
The active hydrogen group in this case includes a hydroxyl group and a mercapto group.
Such amines (B) include diamine (B1), trivalent or higher polyvalent amine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1 to B5. What blocked the group (B6) etc. are mentioned.
Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diamine) Cyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.) and the like.
Examples of the trivalent or higher polyvalent amine (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, when making a prepolymer (A) and amines (B) react, the molecular weight of the isocyanate modified polyester produced | generated using an elongation terminator can be adjusted if necessary.
Examples of the elongation terminator include monoamines having no active hydrogen groups (diethylamine, dibutylamine, butylamine, laurylamine, and the like), and those blocked (ketimine compounds). The addition amount is appropriately selected in relation to the molecular weight desired for the urea-modified polyester to be produced.

  The ratio of the amines (B) and the prepolymer (A) having an isocyanate group is such that the isocyanate group [NCO] in the prepolymer (A) having an isocyanate group and the amino group [NHx] in the amine (B). As an equivalent ratio [NCO] / [NHx] of x (x represents a number of 1 to 2), usually 1/2 to 2/1. Preferably it is 1.5 / 1-1 / 1.5, More preferably, it is 1.2 / 1-1 / 1.2.

  In the present invention, the value (Mw / Tg) obtained by dividing the glass transition point (Tg) and the weight average molecular weight (Mw) of the THF-soluble matter by the glass transition point (Tg / ° C.) is within the specified range. As long as it contains a polyester resin as a binder resin, a resin other than the polyester resin can be used as the binder resin in blend use.

Examples of usable resins other than polyester resins include the following.
Polystyrene, chloropolystyrene, poly α-methylstyrene, styrene / chlorostyrene copolymer, styrene / propylene copolymer, styrene / butadiene copolymer, styrene / vinyl chloride copolymer, styrene / vinyl acetate copolymer, styrene / Maleic acid copolymer, styrene / acrylic acid ester copolymer (styrene / methyl acrylate copolymer, styrene / ethyl acrylate copolymer, styrene / butyl acrylate copolymer, styrene / octyl acrylate copolymer) Styrene / phenyl acrylate copolymer), styrene / methacrylic acid ester copolymer (styrene / methyl methacrylate copolymer, styrene / ethyl methacrylate copolymer, styrene / butyl methacrylate copolymer, styrene) / Phenyl methacrylate copolymer, etc.) Styrene resins (homopolymers or copolymers containing styrene or styrene-substituted products), vinyl chloride resins, styrene / polyethylene styrene / acrylonitrile / acrylic acid ester copolymers, etc. Vinyl acetate copolymer, rosin-modified maleic acid resin, phenol resin, epoxy resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene / ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin Etc., petroleum resins, hydrogenated petroleum resins and the like. The method for producing these resins is not particularly limited, and any of bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used.

As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher, Yellow lead, Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR), Permanent yellow (NCG), Vulcan fast yellow (5G, R) ), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Se Red, parachlor ortho nitro Nirin Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, Riazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Phthalo Cyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used.
The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant used in this embodiment can also be used as a master batch combined with a resin. As the binder resin to be kneaded with the masterbatch or the masterbatch, in addition to the above-mentioned polyester resin, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and its substituted polymers; styrene-p-chloro Styrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid Butyl copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer Polymer, styrene-acrylonitrile copolymer Styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, etc. Styrene copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified Examples thereof include rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, and paraffin wax, which can be used alone or in combination.

The master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch.
In this case, an organic solvent can be used in order to enhance the interaction between the colorant and the resin.
Also known as the flushing method is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used.
For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

Further, a wax can be contained together with the binder resin and the colorant.
Known waxes can be used as the wax used in this example, for example, polyolefin wax (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbon (paraffin wax, sazol wax, etc.); carbonyl group-containing wax, etc. Can be mentioned. 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 -Octadecandiol diol 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 the wax used in this example 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.

The low Tg toner for low temperature fixing used in this embodiment may contain a charge control agent as required.
All known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified). Quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives.
Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Industries, Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo pigments, etc. Sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts.

In the present invention, the amount of charge control agent used is determined uniquely 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 uniquely limited. Although it is not a thing, Preferably it is used in 0.1-10 weight part with respect to 100 weight part of 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.

In this embodiment, inorganic fine particles can be preferably used as an external additive for assisting the fluidity, developability and chargeability of the colored particles.
The primary particle diameter of the inorganic fine particles is preferably 5 × ¹⁰ -3 ~2μm, it is particularly preferably 5 × ¹⁰ -3 ~0.5μm.
Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g.
The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.
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, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride.

In addition, the following materials can be used for the inorganic fine particles.
Polymeric fine particles such as polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization, polycondensation system such as methacrylic acid ester and acrylic acid ester copolymer, silicone, benzoguanamine, nylon, etc. It is a coalesced particle.

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. .
In particular, it is preferable to use hydrophobic silica and hydrophobic titanium oxide obtained by subjecting silica and titanium oxide to the above surface treatment.

Examples of the method for producing a toner for developing an electrostatic charge image according to the present invention are illustrated below, but the present invention is not limited to these methods.
(Preparation of polyester resin) Polyhydric alcohol (PO) and polycarboxylic acid (PC) are heated to 150 to 280 ° C in the presence of a known esterification catalyst such as tetrabutoxy titanate and dibutyltin oxide, and reduced in pressure as necessary. The water produced is distilled off to obtain a polyester resin.

(Prepolymer production)
Polyester having a hydroxyl group obtained by the same method as the above polyester resin is reacted with polyvalent isocyanate (PIC) at 40 to 140 ° C. to obtain a polyester prepolymer (A) having an isocyanate group.
When reacting polyvalent isocyanate (PIC), a solvent can be used as necessary.
Usable solvents are aromatic solvents (toluene, xylene, etc.) that are inert to isocyanate compounds; ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (Dimethylformamide, dimethylacetamide and the like) and ethers (tetrahydrofuran and the like).

(Production of modified polyester resin)
The reaction between the polyester prepolymer (A) and the amines (B) may be carried out by mixing with other toner constituent materials, or may be prepared in advance.
In the case of producing in advance, the polyester prepolymer (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester resin.
Also in the case of reacting the polyester prepolymer (A) and the amines (B), a solvent can be used as necessary, as in the case of the prepolymer (A). Solvents that can be used are as described above.

(Toner production: melt-kneading pulverization method)
The polyester resin, the prepolymer (A), the amines (B), and a toner constituent material such as a colorant, a wax, and a charge control agent are mechanically mixed.
In place of the prepolymer (A) and the amines (B), a modified polyester resin may be mixed.
This mixing step may be performed under normal conditions using a normal mixer with rotating wings, and is not particularly limited.
When the above mixing process is completed, the mixture is then charged into a kneader and melt-kneaded.
As the melt kneader, a uniaxial or biaxial continuous kneader or a batch kneader using a roll mill can be used.
It is important that this melt-kneading is performed under appropriate conditions so as not to cause the molecular chains of the toner binder resin to be broken.
Specifically, the melt-kneading temperature should be performed with reference to the softening point of the toner binder resin. If the temperature is lower than the softening point, cutting is severe, and if the temperature is too high, dispersion does not proceed.

When the above melt-kneading process is completed, the kneaded product is then pulverized.
In this pulverization step, it is preferable to first coarsely pulverize and then finely pulverize.
At this time, a method of pulverizing by colliding with a collision plate in a jet stream or pulverizing with a narrow gap between a rotor and a stator that rotate mechanically is preferably used.
After the pulverization process is completed, the pulverized product is classified in an air current by centrifugal force or the like to produce a toner having a predetermined particle diameter.

Further, in order to improve the fluidity, storage stability, developability, and transferability of the toner, inorganic fine particles such as the above-described hydrophobic silica fine powder are further added to and mixed with the toner manufactured as described above. For mixing external additives, a general powder mixer is used, but it is preferable to use a jacket equipped with a jacket or the like to adjust the internal temperature.
In order to change the load history applied to the external additive, the external additive may be added midway or gradually. Of course, you may change the rotation speed of a mixer, rolling speed, time, temperature, etc.
A strong load may be given first, then a relatively weak load, and vice versa.
Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, a Henschel mixer, and the like.

In order to spheroidize the obtained toner, a toner binder resin, a toner constituent material composed of a colorant is melt-kneaded, and a finely pulverized product is mechanically spheroidized using a hybridizer, mechanofusion, etc. There is a so-called spray drying method in which a toner constituent material is dissolved and dispersed in a solvent in which the toner binder resin is soluble, and then the solvent is removed using a spray drying device to obtain a spherical toner.
Moreover, although the method of making it spherical by heating in an aqueous medium is mentioned, it is not limited to this.

(Toner production method in aqueous medium)
As an aqueous medium used in this embodiment, water alone may be used, but a solvent miscible with water may be used in combination.
Examples of miscible solvents include alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (eg, methyl cellosolve), and lower ketones (acetone, methyl ethyl ketone, etc.).
The toner particles may be formed by reacting a dispersion composed of a polyester prepolymer (A) having an isocyanate group in an aqueous medium with amines (B), or using a modified polyester resin prepared in advance. good.
As a method for stably forming a dispersion composed of a polyester resin or a polyester prepolymer (A) in an aqueous medium, a toner constituent material composed of a polyester resin or a polyester prepolymer (A) is added to the aqueous medium, and shearing is performed. For example, a method of dispersing by force.
Other toner constituent materials such as a colorant, a wax, and a charge control agent may be mixed when forming the dispersion in the aqueous medium. However, after these toner constituent materials are mixed in advance, More preferably, the mixture is added and dispersed.
In the present invention, toner constituent materials such as a colorant, a wax, and a charge control agent are not necessarily mixed when forming particles in an aqueous medium, and are added after the particles are formed. May be.
For example, after forming particles containing no colorant, the colorant can be added by a known dyeing method.

(Solid fine particle dispersant)
Further, by adding a solid fine particle dispersant in advance to the aqueous medium, the dispersion of oil droplets in the aqueous phase is made uniform.
This is because the solid fine particle dispersant is arranged on the surface of the oil droplets at the time of dispersion, and the dispersion of the oil droplets is made uniform, and at the same time, coalescence of the oil droplets is prevented and the particle size distribution is sharp. Toner can be obtained.
The solid fine particle dispersant is present in a solid state hardly soluble in water in an aqueous medium, and is preferably inorganic fine particles having an average particle diameter of 0.01 to 1 μm.
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, silica 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.
More preferably, tricalcium phosphate, calcium carbonate, colloidal titanium oxide, colloidal silica, hydroxyapatite and the like can also be used.
In particular, hydroxyapatite synthesized by reacting sodium phosphate and calcium chloride in water under basic conditions is preferable.

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 of the polyester resin or prepolymer (A) has a low viscosity and is easily dispersed.

  The amount of the aqueous medium used is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight, based on 100 parts by weight of the toner composition containing the polyester resin and the prepolymer (A). 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. The use of a dispersant is preferable in that the particle size distribution becomes sharp and the dispersion is stable.

  As a dispersant for emulsifying and dispersing the oil phase in which the toner composition is dispersed in an aqueous medium, anionic surfactants such as alkylbenzene sulfonate, α-olefin sulfonate, and phosphate ester, alkylamine salts, Amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, and quaternary alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, etc. Nonionic surfactants such as 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, N-jime Amphoteric surfactants such as Le ammonium betaine.

Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount.
Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic 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) carvone Acids and metal salts thereof, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-Hydroxyethyl) perfluoro Kutansulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, and the like It is done.

  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 (manufactured by Taikin Kogyo Co., Ltd.), Mega-Fac F-ll0, F-120, 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 Fgentent F-100, F150 (manufactured by Neos).

  Examples of the cationic surfactant include aliphatic primary, secondary or tertiary amine acids having a fluoroalkyl group, and 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), Florard FC-135 (Sumitomo 3M), Unidyne DS-202 (Daikin Industries) ), Megafuck F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products Co., Ltd.), Footgent F-300 (Neos Co., Ltd.) and the like.

Further, 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 acrylic Amides, N-methylolmethacrylamide, etc. Vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, 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, nitrogen such as vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethylene imine Homopolymers or copolymers such as those having atoms or heterocycles thereof, polyoxyethylene, polyoxypropylene, polyoxyethylene alcohol Lumine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester, etc. Celluloses such as polyoxyethylene, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and the like can be used.

  In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

  When a dispersant is used, the dispersant can remain on the surface of the toner particles. However, 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 polyester resin or the polyester 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 with a boiling point of less than 100 ° C. 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.
The usage-amount of the solvent with respect to 100 weight part of polyester prepolymers (A) is 0-300 weight part normally, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part. 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 crosslinking reaction time is selected depending on the reactivity of the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. It is.
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 obtain the desired shape of the toner, before removing the solvent from the obtained dispersion liquid after the elongation and / or crosslinking reaction, the dispersion liquid is sheared into a stirring tank equipped with a homomixer, an Ebara milder, and a stirrer. Use a device that provides power. In other words, the toner having a desired spherical shape can be produced by immobilizing the particles by deforming the particles having a substantially spherical shape into a spindle shape and then removing the solvent from the dispersion liquid at a Tg or less of the binder resin. It becomes possible.
Examples of the method for adjusting the shearing force include the treatment time and number of treatments of the apparatus, the temperature and viscosity of the dispersion, and the concentration of the organic solvent in the particles.
Also, the particles themselves have different shapes depending on the coverage of the resin fine particles on the surface of the particles, the degree of reactivity with the compound having an active hydrogen group, etc., and the degree of deformation due to the shearing force varies.

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.
A spray dryer, belt dryer, rotary kiln, etc. can achieve the desired quality in a short time.

The resulting dried toner powder is mixed with different particles such as charge control agent, fluidizing agent, and colorant, or fixed and fused on the surface by applying mechanical impact force to the mixed powder. In addition, it is possible to prevent the detachment of the foreign particles from the surface of the obtained 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.) has been modified to reduce the pulverization air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar, etc.

Furthermore, the toner of the present invention can be used as a magnetic toner containing a magnetic substance. Examples of magnetic materials contained in the toner include iron oxides such as magnetite, hematite, and ferrite, metals such as iron, cobalt, and nickel, These metals include alloys of metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium, and mixtures thereof. Magnetite is particularly preferable from the viewpoint of magnetic properties.
These ferromagnetic materials preferably have an average particle size of about 0.1 to 2 μm. The amount of the ferromagnetic material to be contained in the toner is about 15 to 200 parts by weight, particularly preferably 100 parts by weight of the resin component, with respect to 100 parts by weight of the resin component. 20 to 100 parts by weight per part.

  Hereinafter, specific examples relating to the low Tg toner used in this embodiment will be described. In addition, Table 3 shows toners (I) to (IV) obtained in the following production examples as toners obtained in Experimental Examples 1 to 4.

<Production Example 1>
(Example of production of polyester resin) In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introducing tube, 517 parts of bisphenol A ethylene oxide 2-mol adduct, 317 parts of terephthalic acid, 101 parts of ethylene glycol, 65 parts of hydrogenated bisphenol A The mixture was charged and subjected to a condensation reaction at 170 ° C. for 10 hours under an atmospheric pressure of nitrogen, and then the condensation reaction was continued at a reaction temperature of 210 ° C. for 5 hours.
Further, the reaction was continued for 5 hours while dehydrating under a reduced pressure of 0 to 15 mmHg, followed by cooling to obtain a polyester resin (PE1).
The obtained polyester resin (PE1) has a weight-average molecular weight (Mw) of 2,900, an acid value of 5 KOHmg / g, and a glass transition point (Tg) of 43 ° C. The ratio (Mw / Tg) was 67.
Further, the molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 9.5, and the molar ratio of the benzene ring skeleton to the both end ester bond alkylene skeleton was 3.2.

(Prepolymer production example)
Into a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 795 parts of bisphenol A ethylene oxide 2-mole adduct, 200 parts of isophthalic acid, 65 parts of terephthalic acid, and 2 parts of dibutyltin oxide were added, and atmospheric pressure nitrogen was added. Under an air stream, the condensation reaction was performed at 210 ° C. for 8 hours.
Next, the reaction was continued for 5 hours while dehydrating under reduced pressure of 10 to 15 mmHg, then cooled to 80 ° C., and reacted with 170 parts of isophorone diisocyanate in ethyl acetate for 2 hours to obtain a prepolymer (a1).
The obtained prepolymer (a1) had a weight-average molecular weight (Mw) of 5,000 and an average functional group number of 2.25.

(Production example of ketimine compound)
In a reaction vessel equipped with a stir bar and a thermometer, 30 parts of isophorodiamine and 70 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to obtain a ketimine compound (b1).

(Example of toner production)
85 parts of polyester (PE1), 15 parts of prepolymer (a1), 2 parts of ketimine compound (b1), 5 parts of desorbed fatty acid type carnauba wax, 10 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation), metal-containing azo compound 1 part and 5 parts of water are stirred and mixed with a Henschel mixer, heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and the resulting kneaded product is then used with a jet mill and an air classifier. Then, pulverization and classification were performed to obtain a toner base.
To the obtained toner base, 0.5 part of hydrophobic silica was added and mixed to obtain a final toner (I).

<Production Example 2>
(Production example of polyester resin)
613 parts of bisphenol A ethylene oxide 2-mole adduct, 322 parts of terephthalic acid, 13 parts of ethylene glycol, and 52 parts of hydrogenated bisphenol A were charged into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. In the same manner, a polyester resin (PE2) was obtained.
The obtained polyester resin (PE2) has a THF-soluble component weight average molecular weight (Mw) of 5,800, an acid value of 38 KOH mg / g, and a glass transition point (Tg) of 59 ° C. The ratio (Mw / Tg) was 98.
Further, the molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 13.5, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 27.0.

(Example of toner production)
85 parts of polyester resin (PE2), 15 parts of prepolymer (a1), 2 parts of ketimine compound (b1), 5 parts of desorbed fatty acid type carnauba wax, 10 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation), metal-containing azo 1 part of the compound and 5 parts of water were stirred and mixed with a Henschel mixer, then heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and then the resulting kneaded product was jet milled and an air classifier. The toner base was obtained by pulverization and classification.
The final toner (II) was prepared by adding and mixing 0.5 parts of hydrophobic silica to the obtained toner base.

<Production Example 3>
(Production example of polyester resin)
548 parts of bisphenol A ethylene oxide 2-mole adduct, 296 parts of terephthalic acid, 44 parts of ethylene glycol, and 113 parts of hydrogenated bisphenol A were charged into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. In the same manner, a polyester resin (PE3) was obtained.
The obtained polyester resin (PE3) has a THF-soluble component weight average molecular weight (Mw) of 3,300, an acid value of 7 KOH mg / g, and a glass transition point (Tg) of 43 ° C. The ratio (Mw / Tg) was 77.
Further, the molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 5.6, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 7.5.

(Example of toner production)
83 parts of polyester resin (PE3), 17 parts of prepolymer (a1), 2 parts of ketimine compound (b1), 5 parts of desorbed fatty acid type carnauba wax, 10 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation), metal-containing azo 1 part of the compound and 5 parts of water were stirred and mixed with a Henschel mixer, then heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and then the resulting kneaded product was mixed with a jet mill and an air classifier. The toner base was obtained by pulverization and classification.
To the obtained toner base, 0.5 part of hydrophobic silica was added and mixed to obtain a final toner (III).

<Production Example 4>
(Production example of polyester resin)
426 parts of bisphenol A ethylene oxide 2-mole adduct, 350 parts of terephthalic acid, 8 parts of ethylene glycol, and 216 parts of hydrogenated bisphenol A are charged into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. In the same manner, a polyester resin (PE4) was obtained.
The obtained polyester resin (PE4) has a weight-average molecular weight (Mw) of 6,500 in THF, an acid value of 28 KOH mg / g, and a glass transition point (Tg) of 62 ° C. The ratio (Mw / Tg) was 105.
Further, the molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 2.7, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 35.7.

(Prepolymer production example)
Into a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 795 parts of bisphenol A ethylene oxide 2-mole adduct, 200 parts of isophthalic acid, 65 parts of terephthalic acid, and 2 parts of dibutyltin oxide were added, and atmospheric pressure nitrogen was added. Under an air stream, the condensation reaction was performed at 210 ° C. for 8 hours.
Next, the reaction was continued for 5 hours while dehydrating under reduced pressure of 10 to 15 mmHg, then cooled to 80 ° C., and reacted with 150 parts of isophorone diisocyanate in ethyl acetate for 2 hours to obtain a prepolymer (a2).
The obtained prepolymer (a2) had a weight average molecular weight (Mw) of 5,000 and an average functional group number of 2.00.

(Example of toner production)
In a beaker, 14.3 parts of prepolymer (a2), 55 parts of polyester resin (PE4), and 78.6 parts of ethyl acetate were stirred and dissolved.
Separately, 10 parts of rice wax as a release agent, 4 parts of copper phthalocyanine blue pigment and 100 parts of ethyl acetate were placed in a bead mill and dispersed for 30 minutes.
The two liquids were mixed and stirred for 5 minutes at a rotational speed of 12,000 rpm using a TK homomixer, and then dispersed in a bead mill for 10 minutes. This is designated as toner material oil dispersion (1).
In a beaker, 306 parts of ion-exchanged water, 265 parts of tricalcium phosphate 10% suspension, and 0.2 part of sodium dodecylbenzenesulfonate were added, and this aqueous dispersion was stirred with a TK homomixer at 12,000 rpm. The toner material oil dispersion (1) and 2.7 parts of the ketimine compound (b1) were added to the mixture, and the mixture was reacted for 30 minutes while stirring.
The dispersion after the reaction (viscosity: 5,500 mPa · s) is subjected to removal of the organic solvent at a temperature of 50 ° C. or less within 1.0 hour under reduced pressure, followed by filtration, washing and drying, and then air classification. A toner base having a shape was obtained.
100 parts of the obtained base particles and 0.25 parts of a charge control agent (Bontron E-84 manufactured by Orient Chemical Co., Ltd.) were charged into a Q-type mixer (Mitsui Mining Co., Ltd.), and the peripheral speed of the turbine blades was set to 50 m / sec. And mixed.
In this case, the mixing operation was performed for 2 minutes, 5 cycles of 1 minute pause, and the total treatment time was 10 minutes.
Further, 0.5 part of hydrophobic silica (H2000, manufactured by Clariant Japan) was added and mixed.
In this case, the mixing operation was performed at a peripheral speed of 15 m / sec for 5 cycles of 30 seconds mixing and 1 minute to obtain the final toner (IV).

  Table 1 shows the physical properties of the polyester resins (PE1) to (PE4) used in the toners (I) to (IV).

<Production Example 5>
(Production example of polyester resin)
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 585 parts of a bisphenol A ethylene oxide 2-mole adduct, 307 parts of terephthalic acid, 71 parts of ethylene glycol, and 36 parts of hydrogenated bisphenol A were introduced. In the same manner, a polyester resin (PE5) was obtained.
The obtained polyester resin (PE5) has a weight-average molecular weight (Mw) of 2500, an acid value of 9 KOHmg / g, a glass transition point (Tg) of 35 ° C., and a weight-average molecular weight and a glass transition point. The ratio (Mw / Tg) was 71.
Further, the molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 18.5, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 4.8.

(Example of toner production)
85 parts of polyester resin (PE5), 15 parts of prepolymer (a1), 2 parts of ketimine compound (b1), 5 parts of desorbed fatty acid type carnauba wax, 10 parts of carbon black (# 44: manufactured by Mitsubishi Chemical Corporation), metal-containing azo 1 part of the compound and 5 parts of water were stirred and mixed with a Henschel mixer, then heated and melted at a temperature of 130 to 140 ° C. for about 30 minutes with a roll mill, cooled to room temperature, and then the resulting kneaded product was mixed with a jet mill and an air classifier. The toner base was obtained by pulverization and classification.
To the obtained toner base, 0.5 part of hydrophobic silica was added and mixed to obtain a final toner (V).

<Production Example 6>
(Production example of polyester resin)
244 parts of bisphenol A ethylene oxide 2-mole adduct, 443 parts of terephthalic acid, 99 parts of ethylene glycol, and 214 parts of hydrogenated bisphenol A were charged into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. In the same manner, a polyester resin (PE6) was obtained.
The obtained polyester resin (PE6) has a weight-average molecular weight (Mw) of 5,700, an acid value of 18 KOHmg / g, and a glass transition point (Tg) of 45 ° C. The ratio (Mw / Tg) was 127.
The molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 2.4, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 2.6.

(Example of toner production)
In a beaker, 14.3 parts of prepolymer (a1), 55 parts of polyester resin (PE6), and 78.6 parts of ethyl acetate were stirred and dissolved.
Separately, 10 parts of rice wax as a release agent, 4 parts of copper phthalocyanine blue pigment and 100 parts of ethyl acetate were placed in a bead mill and dispersed for 30 minutes.
The two liquids were mixed and stirred for 5 minutes at a rotational speed of 12,000 rpm using a TK homomixer, and then dispersed in a bead mill for 10 minutes. This is designated as toner material oil dispersion (2).
In a beaker, 306 parts of ion-exchanged water, 265 parts of tricalcium phosphate 10% suspension, and 0.2 part of sodium dodecylbenzenesulfonate were added, and this aqueous dispersion was stirred with a TK homomixer at 12,000 rpm. To the toner material oil dispersion (2) and 2.7 parts of the ketimine compound (b1) were added, and reacted while stirring for 30 minutes.
The dispersion after the reaction (viscosity: 3,800 mPa · s) is subjected to removal of the organic solvent at a temperature of 50 ° C. or less within 1.0 hour under reduced pressure, followed by filtration, washing and drying, and then air classification, A toner base having a shape was obtained.
100 parts of the obtained base particles and 0.25 parts of a charge control agent (Bontron E-84 manufactured by Orient Chemical Co., Ltd.) were charged into a Q-type mixer (Mitsui Mining Co., Ltd.), and the peripheral speed of the turbine blades was set to 50 m / sec. And mixed.
In this case, the mixing operation was performed for 2 minutes, 5 cycles of 1 minute pause, and the total treatment time was 10 minutes.
Further, 0.5 part of hydrophobic silica (H2000, manufactured by Clariant Japan) was added and mixed.
In this case, the mixing operation was performed at a peripheral speed of 15 m / sec for 5 cycles of 30 seconds of mixing and 1 minute to obtain the final toner (VI).

<Production Example 7>
(Production example of polyester resin)
393 parts of bisphenol A ethylene oxide 2-mole adduct, 430 parts of terephthalic acid, 121 parts of ethylene glycol, and 57 parts of hydrogenated bisphenol A were charged into a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe. In the same manner, a polyester resin (PE7) was obtained.
The obtained polyester resin (PE7) has a weight-average molecular weight (Mw) of 5,000, an acid value of 11 KOHmg / g, and a glass transition point (Tg) of 41 ° C. The ratio (Mw / Tg) was 122.
The molar ratio of the benzene ring skeleton to the 1,4-cyclohexylene skeleton was 10.8, and the molar ratio of the benzene ring skeleton to the both-end ester bond alkylene skeleton was 2.6.

(Example of toner production)
In a beaker, 14.3 parts of prepolymer (a2), 55 parts of polyester resin (PE7), and 78.6 parts of ethyl acetate were stirred and dissolved.
Separately, 10 parts of rice wax as a release agent, 4 parts of copper phthalocyanine blue pigment and 100 parts of ethyl acetate were placed in a bead mill and dispersed for 30 minutes.
The two liquids were mixed and stirred for 5 minutes at a rotational speed of 12,000 rpm using a TK homomixer, and then dispersed in a bead mill for 10 minutes. This is designated as toner material oil dispersion (3).
In a beaker, 306 parts of ion-exchanged water, 265 parts of tricalcium phosphate 10% suspension, and 0.2 part of sodium dodecylbenzenesulfonate were added, and this aqueous dispersion was stirred with a TK homomixer at 12,000 rpm. To the toner material oil dispersion (3) and 2.7 parts of the ketimine compound (b1) were added, and reacted while stirring for 30 minutes.
The dispersion after the reaction (viscosity: 7,800 mPa · s) is subjected to removal of the organic solvent at a temperature of 50 ° C. or less within 1.0 hour under reduced pressure, followed by filtration, washing, drying, and then air classification, A toner base having a shape was obtained.
100 parts of the obtained base particles and 0.25 parts of a charge control agent (Bontron E-84 manufactured by Orient Chemical Co., Ltd.) were charged into a Q-type mixer (Mitsui Mining Co., Ltd.), and the peripheral speed of the turbine blades was set to 50 m / sec. And mixed.
In this case, the mixing operation was performed for 2 minutes, 5 cycles of 1 minute pause, and the total treatment time was 10 minutes.
Further, 0.5 part of hydrophobic silica (H2000, manufactured by Clariant Japan) was added and mixed.
In this case, the mixing operation was performed at a peripheral speed of 15 m / sec for 5 cycles of 30-second mixing for 1 minute to obtain the final toner (VII).

  Table 2 shows the physical properties of the polyester resins (PE5) to (PE7) used in the toners (V) to (VII).

Using the toners (I) to (IV), the low temperature fixability, the high temperature offset resistance and the heat storage stability were evaluated.
For comparison, the same evaluation was performed using the toners (V) to (VII).
The evaluation items and evaluation methods for the toner are as follows.

<Fixability evaluation>
Ricoh Co., Ltd. Co., Ltd. using a Teflon (registered trademark) roller as a fixing roller. A MF2200 fixing unit was used.
The cold offset temperature (fixing lower limit temperature) and the hot offset temperature (hot offset resistant temperature) were determined by changing the fixing temperature.

The minimum fixing temperature of the conventional low-temperature fixing toner is about 140 to 150 ° C.
The evaluation conditions for the low-temperature fixability are a paper feed linear velocity of 120 to 150 mm / sec, a surface pressure of 1.2 kgf / cm ² , a nip width of 3 mm, and a hot offset evaluation condition of a paper feed linear velocity of 50 mm / sec. sec, surface pressure 2.0 kgf / cm 2, and nip width 4.5 mm.

The criteria for each characteristic evaluation are as follows.
1) Low-temperature fixability (five-step evaluation) A: Less than 130 ° C, B: 130-140 ° C, D: 140-150 ° C, Δ: 150-160 ° C, x: 160 ° C or higher 2) Hot offset resistance (5 Stage evaluation) ◎: 201 ° C or higher, ○: 200-191 ° C, □: 190-181 ° C, Δ: 180-171 ° C, x: 170 ° C or lower

<Evaluation of heat-resistant storage stability>
20g of toner sample is put in a 20ml glass bottle, and the glass bottle is tapped about 50 times to harden the sample tightly, and then left in a high temperature bath at 50 ° C for 24 hours. I asked for it.
3) Heat resistant storage stability (five-step evaluation) A: Penetration, B: ~ 25 mm, D: 25-20 mm, Δ: 20-15 mm, x: 15 mm or less

Table 3 shows the evaluation results of the toner.
As can be seen from Table 3, in Experimental Examples 1 to 4 using the toners (I) to (IV) used in this example, the results were excellent in all of low-temperature fixability, hot offset resistance, and heat storage stability. was gotten.
On the other hand, in Comparative Examples 1 to 3 using the toners (V) to (VII), although low temperature fixability and hot offset resistance were excellent, results inferior in heat resistant storage stability were obtained.

On the other hand, the cleaning device 30 that removes untransferred toner from the photoconductor 10 is provided with a cleaning blade 5 that comes into contact with the surface of the photoconductor 10 and scrapes off foreign matters such as untransferred toner by the cleaning blade 5. It is used.
FIG. 4 is a view for explaining the configuration of the cleaning blade. In the figure, (A) and (B) show the cleaning blade 5 used in this embodiment, and (C) and (D) show conventional examples corresponding to comparative examples with the cleaning blade in this embodiment. ing.
In FIG. 4A, the cleaning blade 5 is composed of a strip-shaped holder 5A made of a rigid material such as metal or hard plastic, and a strip-shaped elastic blade 5B. The elastic blade 5B is fixed to one end side of the holder 5A by an adhesive or the like, and the other end side of the holder 5A is cantilevered by the case of the cleaning device 30.
As shown in FIG. 4A, the elastic blade 5B is a laminated blade composed of two layers of an edge layer 5B1 and a backup layer 5B2.
The edge layer 5 </ b> B <b> 1 is composed of a blade member made of a layer having a tip ridge line portion 5 </ b> B <b> 3 that is in direct contact with the photoreceptor 10.

In this embodiment, the edge layer 5B1 uses a urethane rubber material having a higher strength than the backup layer 5B2. The edge layer 5B1 has a 100% modulus value that is larger than that of the backup layer 5B2.
As an example of the combination of the edge layer 5B1 and the backup layer 5B2, a urethane rubber material having a 100% modulus value (23 [° C.]) of 6 to 7 [Mpa] is used as the edge layer 5B1, and the backup layer 5B2 is 4 to 4 A urethane rubber material of 5 [Mpa] was used.
However, the edge layer 5B1 can be suitably used as long as the 100% modulus value (23 [° C.]) is in the range of 6 [Mpa] to 12 [Mpa]. In addition, in terms of rubber hardness, urethane rubber of 80 degrees (JISA) was used for the edge layer 5B1 and urethane rubber of rubber hardness 75 degrees (JISA) was used for the backup layer 5B2. The thickness of the edge layer 5B1 is 0.5 [mm], and the thickness of the backup layer 5B2 is 1.3 [mm].

On the other hand, the cleaning blade 5 ′ using a single-layer elastic blade conventionally used in FIG. 4C is a urethane rubber having a 100% modulus (23 ° C.) of 4.6 [MPa] and a hardness of about 72 degrees. Material is used. In such a conventional single-layer cleaning blade 5 ', even if it is kept in contact with the photoconductor 10 for a long period of time, it is difficult to cause settling and the initial contact state can be maintained.
However, since the hardness is low, deformation at the edge portion that comes into contact with the photoconductor 10 is large, and the contact area is widened, so the contact pressure is low. For this reason, the ability to remove toner and deposits on the surface of the photoreceptor is low, and a part of the dammed toner abuts on the photoreceptor 10 and slips through the deformed edge portion little by little due to the wedge effect.

Therefore, in the present embodiment, as shown in FIG. 4B, in the cleaning blade 5, the strength of the tip ridge line portion 5B3 is increased due to the effect of the edge layer 5B1 made of a high-strength material. For this reason, compared with the cleaning blade 5 ′ made of low-hardness elastic rubber shown in FIG. 4C, it is possible to suppress the deformation at the edge portion 5B1 and to prevent the contact area from expanding.
This makes it possible to increase the contact pressure. As a result, the ability to remove toner and adhered matter on the surface of the photoreceptor is high, and it is possible to sufficiently suppress a part of the dammed toner from slipping through the edge portion.

Further, as described above, in the elastic blade 5B, the edge layer 5B1 in contact with the photoconductor 10 has a high hardness to improve the cleaning performance, while the backup layer 5B2 is made of a material having a smaller 100% modulus value than the edge layer 5B1. It has a laminated structure.
This is because when a high-strength material with high hardness is used as a single layer as in the conventional cleaning blade 5 ′, the spread of the nip can be suppressed, but the following problem occurs. In other words, there is a risk that the long-term use will cause settling, causing a decrease in the contact pressure and the like, resulting in a decrease in cleaning performance.
As in this embodiment, the elastic blade 5B has a two-layer structure, and the backup layer 5B2 is made of a material having a low strength and a small 100% modulus value compared to the edge layer 5B1, so that Prevents contact pressure drop. Thereby, it is possible to maintain a good cleaning performance for a longer period. As a result, high reliability and long life are achieved.

In order to improve the toner removal performance, it is effective to suppress stick slip of the blade tip ridge line portion 5B3, and it is effective to reduce the rebound resilience of the edge layer 622b in contact with the photoconductor 10.
However, by reducing the resilience, the cleaning performance in a low temperature environment is lowered. For this reason, in the elastic blade 5B of this embodiment, it is desirable that the magnitude relationship between the resilience of the edge layer 5B1 and the resilience of the backup layer 5B2 satisfies the following relationship at least at 10 ° C.
Rebound resilience of the edge layer <Rebound resilience of the backup layer The rebound resilience of the backup layer 5B2 is made larger than that of the edge layer 5B1, thereby optimizing the rebound resilience of the entire elastic blade 5B having a laminated structure. Thereby, the cleaning performance in a low temperature environment can also be ensured.

Furthermore, in order to improve the cleaning performance, it is effective to increase the tan δ peak temperature of the edge layer 5B1 in contact with the photoconductor 10. Thereby, the rubber property in a low temperature environment can be reduced and the step slip motion of a blade can be reduced.
However, when the tan δ peak temperature is increased, the cleaning performance in a low temperature environment is lowered. For this reason, in the elastic blade 5B in the present embodiment, the relationship between the tan δ peak temperature of the edge layer 5B1 and the tan δ peak temperature of the backup layer 5B2 is as follows.
Tan δ peak temperature of the edge layer> tan δ peak temperature of the backup layer Thereby, by reducing the tan δ peak temperature of the backup layer 5B2, the rubber property of the backup layer 5B2 is increased, and the tan δ peak of the entire elastic blade 5B having the laminated structure is obtained. Adjust the temperature. Thereby, the cleaning performance under a low temperature environment can be ensured.

  Specific examples 1 to 3 relating to the cleaning blade 5 employed in the printer 100 shown in FIG.

In specific examples 1 to 3, a rubber material having a 100% modulus (23 [° C.]) of the edge layer 5B1 of 6 [Mpa] is used, and deformation at the edge portion is reduced to prevent filming. Further, by using a rubber material whose hardness is lower than that of the edge layer 5B1 as the backup layer 5B2, it is possible to prevent settling due to long-term use and a decrease in contact pressure. As a result, good cleaning performance is maintained for a longer period.
In the second specific example, the rebound resilience of the edge layer 5B1 is reduced as compared with the first specific example, and the stick-slip phenomenon at the edge portion is suppressed to stabilize the behavior of the edge, thereby further improving the cleaning performance.

In specific example 3, the 100% modulus of the backup layer 5B1 is further lowered than in specific example 1, the contact pressure of the elastic blade 5B to the photoconductor 10 is reduced, and the blade wear is suppressed, and the cleaning performance is maintained over a long period of time. Has been able to maintain.
Furthermore, in the specific examples 1 and 2, the rebound resilience of the backup layer 5B2 at 10 ° C. is made larger than the rebound resilience of the edge layer 5B1, thereby optimizing the rebound resilience of the laminated elastic blade 622 as a whole. Further, the tan δ peak temperature of the entire elastic blade 5B having the laminated structure is optimized by making the tan δ peak temperature of the backup layer 5B2 smaller than the tan δ peak temperature of the edge layer 5B1. This ensures the cleaning performance in a low temperature environment.

The characteristics of this embodiment will be described below for the image forming apparatus having the above configuration.
In this embodiment, there is a feature in the cleaning member that is a cleaning member for the charging device 40. Specifically, the linear velocity of the cleaning member is changed by changing the contact pressure of the charging member with the cleaning member that can be driven by the charging member. The mode is that the ratio can be changed.
Hereinafter, configurations of the charging device 40 and the cleaning unit will be described.

As shown in FIG. 2, the charging device 40 is a cleaning member that can remove a foreign matter adhering to the surface of the charging roller 41 by contacting the surface of the charging roller 41 and the surface of the charging roller 41 and rotating the charging roller 41. The roller 42 is provided as a main part.
The charging roller 41 is a member to which a constant DC voltage is applied as a charging bias, and is configured by providing a conductive rubber layer on a cored bar as shown in FIG. The uneven | corrugated-shaped grinding | polishing part 41A formed along the circumferential direction is provided at random.
The surface roughness Rz using unevenness is set to 10 μm or more, preferably about 15 μm.
When the surface roughness is 10 μm or less and the unevenness becomes small, it becomes easy to obtain an abnormal image in which horizontal streaks or the like occur, and since the unevenness becomes small, current flows easily along the surface of the charging roller, and current leakage occurs. There is a possibility that a horizontal streak is likely to occur due to the phenomenon. On the contrary, if the surface roughness Rz is too large, unevenness unevenness may be reflected in the halftone image as it is and appear as density unevenness. For this reason, as an upper limit of surface roughness, it is desirable to suppress to about 20 micrometers.

Regarding the surface roughness Rz of the charging roller 41, the configuration shown in FIG. 6 can also be used.
That is, the surface of the charging roller 41 has a two-layer structure of a conductive layer and a base layer, and a large number of particles 41A ′ having a particle size of about 15 μ are dispersed in the surface layer. An uneven portion is formed on the surface by the particles 41A ′. The surface roughness Rz was measured with Surfcom 1400D (manufactured by Tokyo Seimitsu).

On the other hand, a cleaning roller 42 that can contact the surface of the charging member, that is, the surface of the charging roller 41 is used for the cleaning unit.
As the cleaning roller 42, a roller provided with a polyurethane sponge layer on a metal core or a brush roller provided with fibers of conductive or insulating polyamide, acrylic resin, polyester resin or the like is used.

FIG. 7 shows a mechanism for bringing the cleaning roller 42 into contact with the charging roller 41, and this mechanism is used as a mechanism for pressing the cleaning roller 42 against the charging roller 41.
In the figure, a cleaning roller 42 is a member that can be driven to rotate by the charging roller 41 by supporting a support shaft 42A by a bearing 203.
One end of the pressure spring 202 in the expansion / contraction direction is locked to the bearing 203, and the other end of the pressure spring 202 in the expansion / contraction direction is locked to a sliding spacer 201 that is in contact with the eccentric cam 200.

FIG. 8 is a perspective view of the pressure mechanism of the cleaning roller 42.
As shown in the figure, a pressure spring 202 is disposed in a bearing 203 that supports the support shaft 42A of the cleaning roller 42 and a sliding spacer (not shown) that contacts the peripheral surface of the eccentric cam 200. Has been.
The eccentric cam 200 is rotatably supported by a support shaft 200A disposed at a position different from the support shaft 42A of the cleaning roller 42, and the support shaft 200A is rotationally driven by a drive motor (not shown). It has become.
Although not shown in detail, the bearing 203 is enclosed by a bearing that supports the support shaft 41 </ b> A of the charging roller 41 and is provided integrally with the charging roller 41.

The pressure spring 202 can be expanded and contracted according to the cam profile of the eccentric cam 200, and the bearing 203 is displaced by a change in elastic force according to a change in the amount of expansion and contraction, thereby applying the cleaning roller 42 to the charging roller 41. The pressure can be changed.
That is, the state shown in FIG. 7A is a state in which the pressure spring 202 is contracted. In this state, the elastic force of the pressure spring 202 increases, so that the pressing force of the cleaning roller 42 against the charging roller 41 is increased. Strengthened.
The state shown in FIG. 7B is a state in which the pressure spring 202 is extended. In this state, the charging roller 41 is weakened because the elastic force of the pressure spring 202 is weaker than that in the state shown in FIG. The pressure of the cleaning roller 42 against the pressure is weakened.

In this embodiment, the linear speed ratio between the charging roller 41 and the cleaning roller 42 is changed by the change in the pressing force of the cleaning roller 42 with respect to the charging roller 41.
The linear velocity ratio in this case is a value obtained by “linear velocity ratio = cleaning roller rotational linear velocity / charging roller rotational linear velocity”.
That is, in the state shown in FIG. 7A, since the pressing force of the cleaning roller 42 against the charging roller 41 is strong, the rollers follow at a substantially constant speed. As a result, the cleaning roller 42 is in a state where the scraping action of the foreign matter from the surface of the charging roller 41 is weak.
In this embodiment, this state is referred to as a first mode in a driven rotation state.
On the other hand, in the state shown in FIG. 7B, since the pressure of the cleaning roller 42 against the charging roller 41 is weak, the linear velocity ratio between both rollers is increased. As a result, the cleaning roller 42 rotates at a slower linear speed than the charging roller 41, thereby enhancing the scraping action of foreign matters adhering to the surface of the charging roller 41.
In this embodiment, this state is referred to as a second mode of the driven rotation state.

FIG. 9 is a diagram showing the results of experiments on the linear speed ratio when the pressure applied by the cleaning roller 42 to the charging roller 41 is changed.
In the figure, the linear velocity ratio is confirmed by measuring the rotational speeds of the cleaning roller and the charging roller and obtaining the linear velocity from the outer diameter of each roller. The cleaning roller 42 was confirmed using a urethane roller made of polyurethane foam EP70 manufactured by Inoac Corporation and a nylon fiber brush roller having a fineness of 0.9 dtex.

As shown in FIG. 9, when a urethane roller is used as the cleaning roller 42, the linear speed ratio changes approximately in proportion to the applied pressure. On the other hand, when the brush roller is used as the cleaning roller 42, the change in the linear speed ratio is large when the pressurizing force is low. In either case, the linear speed ratio decreases when the pressurizing force is lowered.
In the case of a urethane roller, the linear speed ratio, which is a constant speed state with respect to the charging roller, is 100% or more at a certain pressure or more. Here, the state of exceeding 100% does not mean that the cleaning roller 42 is rotating at a higher rotational linear speed than the charging roller 41 which is a drive source, despite the accompanying rotation.
The urethane roller is deformed as the applied pressure is increased, and the substantial outer diameter of the rotation is reduced. In addition, the brush roller has a smaller linear velocity ratio at the same pressure than the urethane roller, and it is estimated that the friction coefficient against the charging roller is small. It was. However, when the applied pressure is lowered as described above, the state where the charging roller is rotated at a slow linear speed is the same.

In the present embodiment, the first mode and the second mode described above can be selected, and this selection is performed by the control unit shown in FIG.
FIG. 10 is a block diagram illustrating a configuration of the control unit 1000 used for the image forming process. In the drawing, the following configuration is used as a configuration related to the present embodiment.
Connected to the input side of the control unit 1000 are an operation panel 1001 for discriminating between image formation and non-image formation, a printed sheet counter 1002, and a timer 1003 for measuring elapsed printing time, and an eccentric cam 200 on the output side. Drive motor M is connected.

In the control unit 1000, the first mode is selected when the image is formed, and the second mode is selected when the non-image is formed, when the apparatus is started up, when a predetermined number of times are printed, or when the printing progresses. It corresponds to the time elapsed.
When each of these modes is selected, the control unit 1000 adjusts the pressing force of the pressure spring 202 by changing the rotational phase of the eccentric cam 200.

In the present embodiment, the foreign matter cleaning efficiency from the charging roller 41 by the cleaning roller 42 can be maintained only by adjusting the contact pressure of the cleaning roller 42 with respect to the charging roller 41.
That is, in the driven rotation state of the cleaning roller 42 with respect to the charging roller 41 according to the input information, the first mode in which the cleaning roller 42 is driven at substantially the same speed as the charging roller 41 and a line slower than in the first mode. By simply selecting one of the second modes in which the cleaning roller 42 is driven by the charging roller 41 at high speed, scraping (sliding) foreign matters such as untransferred toner and wear powder adhering to the surface of the charging roller 41 is achieved. ) Can control efficiency. As a result, it is possible to maintain stable surface cleaning regardless of the state of the charging roller 41 over time.

By the way, considering that the contamination of the charging roller 41 gradually accumulates with time, the conditions for selecting the second mode described above are images that affect changes in the usage environment such as temperature and humidity and the degree of occurrence of untransferred toner. It is also possible to use area, image density, and the like.
Furthermore, the mode to be selected is not limited to the first and second modes, and it is possible to select a mode of two or more stages by controlling the rotation angle of the eccentric cam 200.
In any case, it is preferable to perform mode selection based on the result of determining the degree of contamination of the charging roller 41.

  In the embodiment described above, the linear velocity obtained by maintaining both of the driven relationships only by changing the contact pressure of the cleaning roller 42 with respect to the charging roller 41 by judging the degree of contamination of the charging roller based on various input conditions. The charging roller 41 can be cleaned using the ratio. As a result, the contamination of the charging roller 41 can be cleaned according to the situation in any situation, so that it is possible to prevent the charging characteristics from being changed due to the dirt on the charging roller 41 over a long period of time. As a result, it is possible to maintain a state in which no abnormal images are generated due to inheritance defects over a long period of time.

DESCRIPTION OF SYMBOLS 10 Photoconductor 30 Charging device 41 Charging roller 42 Cleaning roller 200 Eccentric cam 200A Spindle 202 Pressing spring 1000 Control unit 1001 Operation panel 1002 Printed sheet counter 1003 Timer M Drive motor

JP 2001-95752 A JP-A-10-90982 JP 2010-2648 A JP 2010-32574 A

Claims (11)

A charging device comprising a charging member used for uniformly charging the surface of a latent image carrier and a cleaning member capable of removing foreign matter attached to the surface of the charging member in contact with the surface of the charging member,
The cleaning member can select a driven rotation state with respect to the charging member in a first mode and a second mode by changing a contact pressure with respect to the charging member,
The charging device is characterized in that the second mode is set so that a linear speed ratio of the cleaning member to the charging member is larger than that of the first mode.   The charging device according to claim 1, wherein the first mode is a mode in which the cleaning member is driven at a substantially constant speed with respect to the charging member.   2. The charging device according to claim 1, wherein the second mode is a mode in which the cleaning member is driven by the charging member at a linear velocity slower than that in the first mode.   As a configuration for changing the contact pressure of the cleaning member with respect to the charging member, a spring capable of changing an elastic force in accordance with a change in expansion / contraction amount is used, and the spring has one end in the expansion / contraction direction on a rotatable eccentric cam. The charging device according to claim 1, wherein the contact pressure is changed by changing an amount of expansion and contraction by facing each other.   The charging device according to claim 1, wherein the cleaning member is movable in the same direction at a position facing the charging member. A charging device comprising a charging member used for uniformly charging the surface of a latent image carrier and a cleaning member capable of removing foreign matter attached to the surface of the charging member in contact with the surface of the charging member,
The cleaning member can select a driven rotation state with respect to the charging member in a first mode and a second mode by changing a contact pressure with respect to the charging member,
The second mode is set such that a linear speed ratio of the cleaning member to the charging member is larger than the first mode.
The charging device according to claim 1, wherein a plurality of irregularities extending along a circumferential direction are formed on a surface of the charging member. A charging device comprising a charging member used for uniformly charging the surface of a latent image carrier and a cleaning member capable of removing foreign matter attached to the surface of the charging member in contact with the surface of the charging member,
The cleaning member can select a driven rotation state with respect to the charging member in a first mode and a second mode by changing a contact pressure with respect to the charging member,
The second mode is set such that a linear speed ratio of the cleaning member to the charging member is larger than the first mode.
The charging device is characterized in that a large number of particles are dispersed on a surface thereof.   The charging device according to claim 1, wherein a direct current constant voltage is applied to the charging member. An image forming apparatus using the charging device according to any one of claims 1 to 8,
The latent image carrier is provided with a cleaning device for removing foreign matters such as untransferred toner and abrasion powder,
The cleaning device includes a blade member having a tip ridge line portion in contact with the surface of the latent image carrier, and the blade member has an elastic rubber whose tip ridge line portion has a 100% modulus value at 23 ° C. of 6 [MPa] or more. An image forming apparatus characterized in that is used.   The image forming apparatus according to claim 9, wherein a toner having a glass transition point of 40 to 60 ° C. is used as the toner that is not transferred.   11. The image forming section includes a process cartridge that houses at least one of a charging device, a developing device, and a cleaning device for performing image forming processing on the latent image carrier. The image forming apparatus described.

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