JP2003107791A - Toner, image forming method and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toners which are hardly environmentally affected, have stable electrostatic charging performance and have high transferability and to provide an image forming method and image forming device decreased the toners remaining after transfer, suppressed in toner fusion to a photoreceptor and the contamination of a electrostatic charging member. SOLUTION: The toners containing at least a binder resin and coloring agents have toner particles and particulates and have average circularity of 0.950 to 0.955, in which the particulates are tin oxide particulates containing a tungsten element and the molar ratio (Sn/W) of the tungsten element (W) to the tin element (Sn) is 0.001 to 0.3. The above toners are used in the image forming method and the image forming device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a toner used in a recording method using an electrophotographic method, an electrostatic recording method, a magnetic recording method, a toner jet recording method, an image forming method and the image forming method. The present invention relates to the image forming apparatus. More specifically, the present invention relates to a toner used in a copying machine, a printer, a fax, an image forming method, and the image forming method, which forms a toner image on an image carrier in advance and then transfers the image onto a transfer material to form an image. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, a large number of electrophotographic methods are known, but in general, a photoconductive material is used, and an electrostatic charge image carrier (hereinafter referred to as "photoreceptor") is formed by various means.
An electrostatic latent image is formed on the latent image, and then the latent image is formed into a visible image by using toner. After the toner image is transferred to a transfer material such as paper as necessary, the latent image is transferred onto the transfer material by heat or pressure. The toner image is fixed on the sheet to obtain a copy.

The developing method includes a one-component developing method and a two-component developing method. The one-component developing method does not require carrier particles such as glass beads and iron powder unlike the two-component developing method. Can be made smaller and lighter. Further, since the two-component developing method needs to keep the toner concentration in the developer constant, an apparatus for detecting the toner concentration and supplying a required amount of toner is required. Therefore, also in this case, the developing device becomes large and heavy. Such a device is not required in the one-component developing method, and it is preferable because it can be made small and light.

However, the one-component developing method using the insulating magnetic toner has an unstable factor related to the insulating magnetic toner used. This is because the magnetic powder in the form of fine powder is mixed and dispersed in the insulating magnetic toner in a considerable amount, and a part of the magnetic powder is exposed on the surface of the toner particle. The frictional electrification property is affected, and as a result, various characteristics required for the magnetic toner such as developing characteristics and durability of the magnetic toner are changed or deteriorated.

When the conventional magnetic toner containing the magnetic powder is used, the above-mentioned problems may be caused largely by the fact that the magnetic powder is exposed on the surface of the magnetic toner. . That is, by exposing the magnetic powder fine particles having a relatively low resistance as compared with the resin constituting the toner to the surface of the magnetic toner, the toner charging performance is deteriorated, the toner fluidity is deteriorated, and moreover, it is used for a long time. In the case of using, the image density is reduced due to the peeling of the magnetic powder due to the friction between the toners or the regulating member, and the deterioration of the developer such as the occurrence of uneven density called a sleeve ghost is caused.

JP-A-62-279352, JP-B-3-9045, JP-A-61-34070, etc. have proposed a magnetic iron oxide contained in a magnetic toner, but the toner is It still has some points to be improved such as poor fluidity and weakness against mechanical shock.

On the other hand, the toner is manufactured by manufacturing a toner having a desired particle diameter by melting and mixing a binder resin, a colorant and the like, uniformly dispersing them, pulverizing them with a fine pulverizer and classifying them with a classifier. However, it is difficult for the pulverization method to completely and uniformly disperse solid fine particles such as magnetic powder or a coloring agent in the resin. Depending on the degree of dispersion, increase in fog, image It causes a decrease in concentration.
Further, the pulverization method essentially exposes the magnetic iron oxide particles to the surface of the toner, so that problems still remain in the fluidity of the toner and the charging stability in a harsh environment.

In order to overcome the problems of the toner by the pulverization method as described above, and further, in order to meet the above requirements, a method for producing a toner by the suspension polymerization method has been proposed.

The toner obtained by suspension polymerization (hereinafter, referred to as a polymerized toner) can be easily made into fine particles, and since the obtained toner has a spherical shape, it has excellent fluidity and high image quality. It is advantageous for

However, when the magnetic powder is contained in the polymerized toner, its fluidity and charging characteristics are significantly lowered. This is because the magnetic powder is generally hydrophilic and therefore tends to exist on the toner surface. In order to solve this problem, it is important to modify the surface characteristics of the magnetic powder.

Many proposals have been made regarding surface modification for improving the dispersibility of magnetic powder in polymerized toner. For example, JP-A-59-200254 and JP-A-59-2
Various silane coupling agent treatment techniques for magnetic powders have been proposed in JP-A-00256, JP-A-59-200257 and JP-A-59-224102, and in JP-A-63-250660, A technique of treating silicon-containing magnetic particles with a silane coupling agent is disclosed, and JP-A-7-72654 discloses a technique of treating magnetic iron oxide with an alkyltrialkoxysilane.

However, although these treatments improve the dispersibility in the toner to some extent, there is a problem in that it is difficult to uniformly make the surface of the magnetic powder uniform. The generation of non-hydrophobicized magnetic powder particles cannot be avoided, and it is insufficient to improve the dispersibility in the toner to a good level.

Regarding a special toner in which magnetic powder particles are contained only in a specific part inside the particles, Japanese Patent Laid-Open No. 7-2
It has already been disclosed in Japanese Patent Publication No. 09904. However, JP-A-7-209904 does not mention the circularity of the toner.

LED and LBP printers have become the mainstream of the market in recent years, and the direction of technology is higher resolution, that is, 240, 300 dpi is now 400, 600, 800 dpi. . Accordingly, the developing system is also required to have higher definition. Further, the copiers are also becoming more sophisticated, and as a result, they are moving toward digitalization. In this direction, the method of forming an electrostatic latent image with a laser is the main method, so it is also advancing toward the direction of high resolution, and here again, as with printers, high resolution and high definition developing methods are required. There is. For this reason, the particle size of the toner is being reduced.

With respect to the charging method, in recent years, from the viewpoint of environmental protection, instead of the primary charging and transfer process using corona discharge that generates a large amount of ozone, the primary charging and transfer process using a photoconductor contact member. (Contact charging method and contact transfer method) are becoming mainstream. However, it has been found that the contact charging method or the contact transfer method has a worrisome problem, unlike the case of using the corona discharge.

Specifically, in the case of the contact transfer method, when the transfer member is brought into contact with the photoconductor through the transfer member during transfer, the toner image formed on the photoconductor is transferred to the transfer material. The toner image is pressed against the sheet, causing a problem of partial transfer failure, which is called a so-called void in transfer. Further, as the direction of recent technology, there is a demand for a higher resolution and higher definition developing method, and in order to meet such a demand, the toner particle size is being reduced. Thus, as the toner particle size becomes smaller, the adhesion force (image force, van der Waals force, etc.) of the toner particles to the photoconductor becomes larger than the Coulomb force applied to the toner particles in the transfer process.
As a result, the transfer residual toner increases, and the transfer failure tends to be further aggravated.

On the other hand, in the contact charging method, the charging member is pressed against the surface of the photoconductor with a pressing pressure. Therefore, when untransferred residual toner, that is, transfer residual toner, is pressed against the surface of the photoconductor, toner fusing is likely to occur due to abrasion or scraped parts due to scraping of the photoconductor surface. The larger the amount of residual toner, the more remarkable it appears.

The scraping of the photosensitive member and the toner fusion are
It causes a serious defect in the formation of an electrostatic latent image on the image carrier. Specifically, abrasion of the photoconductor makes primary charging impossible,
The scraped parts appear black on the halftone image.
Further, since toner fusion makes it impossible to form a latent image by exposure, the fused portion appears white on the halftone image. Further, the transferability of the toner will be deteriorated. Therefore, in combination with the above-mentioned transfer failure, a remarkable image defect appears, and in some cases, the image quality deteriorates synergistically.

The problems such as abrasion of the photosensitive member and defective transfer are likely to occur when a developer containing irregular toner particles is used. It is considered that this is because the transferability of the irregular toner is low, and the edge portion of the toner particle easily scratches the surface of the photoconductor. Further, the problem of shaving becomes particularly noticeable when a magnetic developer in which magnetic powder is exposed on the surface of toner particles is used. This is easily understandable considering that the exposed magnetic powder is directly pressed against the photoconductor.

Further, if the transfer residual toner increases, it becomes difficult to maintain sufficient contact between the contact charging member and the photosensitive member, and the charging property deteriorates. Therefore, in reversal development, the toner is transferred to the non-image area. That is, fog is likely to occur. This phenomenon is often seen under low humidity where the resistance of the member tends to increase.

As described above, in the image forming method using the contact charging method and the contact transfer method, which are very preferable in consideration of the environment, the magnetic developer has a high transfer property and is less likely to cause abrasion of the photosensitive member or toner fusion. Development is desired.

On the other hand, when the toner image formed on the photoconductor in the developing step is transferred to the transfer material in the transfer step and the transfer residual toner remains on the photoconductor as described above, it is cleaned in the cleaning step. , Need to be stored in the waste toner container. For this cleaning step, conventionally, blade cleaning, fur brush cleaning, roller cleaning, etc. are used. In either method, the transfer residual toner is mechanically scraped off or dammed and collected in a waste toner container. However, when such a member is pressed against the surface of the photoconductor, the photoconductor is worn away, and the life of the photoconductor is shortened. Further, the transfer residual toner is collected while being pressed between the cleaning member and the surface of the photoconductor in the cleaning step, and therefore, when the process speed is increased or the photoconductor is used in a high temperature environment, the photoconductor in the cleaning unit is exposed. Toner fusion to the body is likely to occur. Moreover, from the viewpoint of the apparatus, the apparatus is inevitably large in size due to the provision of such a cleaning apparatus, which becomes a bottleneck when the apparatus is made compact. Further, from the viewpoint of ecology, a system that does not generate waste toner is desired in the sense of effectively utilizing the toner.

Incidentally, in the developing / cleaning constitution essentially having no cleaning device, the surface of the photoconductor is rubbed with the toner and the toner carrier, the toner of the non-image portion is recovered by the toner carrier, and the toner of the image portion is collected. It is necessary to have a structure for developing with. At the time of this rubbing, if the reversely charged toner such as the transfer residual toner or the fog toner can be easily reversed to the positive charge, the potential recovery becomes easy.

Conventionally, when the toner containing the magnetic powder is used in the developing / cleaning constitution, the magnetic powder is exposed on the surface of the toner. Therefore, it is difficult to obtain a high-definition image because the electrostatic charge increase on the photoconductor is disturbed. Further, in the magnetic toner in which the magnetic powder is exposed on the toner surface, the transfer residual toner is insufficiently charged, which hinders the smooth recovery of the toner on the photoconductor in the developing step. Further, when the photoconductor is rubbed against the toner and the toner carrier, the photoconductor is heavily worn by the magnetic powder exposed on the toner surface, which shortens the life of the photoconductor. As a result, the originally imageless area becomes a so-called ghost image, which is a printed image in which the toner image-likely becomes dirty.

As described above, it is desired that the magnetic powder-containing toner used in the developing / cleaning structure does not have the magnetic powder exposed on the toner surface.

On the other hand, many methods have been proposed in which conductive fine particles are added as an external additive to the toner for the purpose of obtaining high transfer performance by improving the charging property of the toner and making the tribo distribution of the toner uniform. There is.

For example, carbon black as conductive fine particles adheres to or adheres to the toner surface for the purpose of imparting conductivity to the toner or suppressing excessive charging of the toner and uniforming tribo distribution. It is widely known to be used as an external additive for JP-A-57-151952, JP-A-59-168458
Japanese Patent Laid-Open No. 60-69660 and Japanese Patent Laid-Open No. 60-69660 disclose external addition of conductive fine particles of tin oxide, zinc oxide, and titanium oxide to a high-resistance magnetic toner. Further, in Japanese Patent Laid-Open No. 56-142540, by adding conductive magnetic particles such as iron oxide, iron powder, and ferrite to a high-resistance magnetic toner, the conductive magnetic particles promote charge induction to the magnetic toner. Toners having both developability and transferability have been proposed. Furthermore, JP-A-61-275864, JP-A-62-258472 and JP-A-61-1
JP-A-41452 and JP-A-02-120865 disclose that graphite, magnetite, conductive particles of polypyrrole, and conductive particles of polyaniline are added to the toner, and various conductive particles are added to the toner. It is known.

However, by using these conductive fine particles, the uniformity of tribo distribution of the toner is improved to some extent, but the fluctuation of the charging characteristics due to the environment, the deterioration of the fluidity of the toner during the printing of a large number of sheets, and the contamination of the members. As for the problems such as abrasion of the photoconductor, fusion to the photoconductor, and image defects due to contamination of the charging member by the transfer residual toner in the cleanerless system, sufficient performance has not yet been obtained.

Further, in JP-A-6-175392, a known metal oxide (alumina, zinc oxide, tin oxide, etc.) having a volume resistance value of 1 × 10 ⁵ to 1 × 10 ⁸ Ωcm is used.
It is added to the binder resin that constitutes the toner. further,
Reduced metal oxide (Japanese Patent Publication No. 07-113781), antimony-containing tin oxide (Japanese Patent Laid-Open No. 06-1186)
No. 93), carbon black powder, metal particles, and other low resistance particles are externally added to the toner. However, although known metal oxides such as alumina, zinc oxide, and tin oxide show a resistance value of about 1 × 10 ⁶ to 1 × 10 ⁷ Ωcm under the influence of hydroxyl groups on the surface under the environment of normal temperature and normal humidity, Since the resistance of the resistance is highly dependent on humidity and constantly fluctuates, the physical properties may not be stable even if it is contained in the toner.

Further, tin oxide containing antimony is
Since conductivity can be easily expressed by baking in the air atmosphere, resistance fluctuation due to humidity is prevented, but the baked product exhibits a blue to black blue color, and when externally added to the toner, When tin oxide released from the toner in the forming process is transferred to the transfer paper, the image quality is deteriorated due to color. Further, addition to the color toner also causes a decrease in color reproducibility.

Oxides which exhibit conductivity by firing a metal oxide such as tin oxide or titanium oxide in a reducing atmosphere such as hydrogen gas to reduce a part of the tin component, or carbon black are Due to the reduction treatment, the fired product becomes blackish and causes the color reproducibility of the toner and the deterioration of the image quality as in the case of tin oxide containing antimony.

A low resistance material such as metal particles lacks long-term stability because it may cause a leak phenomenon in a developing process requiring a high electric field.

Japanese Unexamined Patent Publication No. 5-173372 describes that the inorganic fine particles surface-treated with a conductive treatment agent or the like are contained in the toner surface, the carrier surface, or the carrier coating resin. However, specific embodiments are described. And is completely different from the technical idea and configuration of the present invention.

Further, in JP-A-5-61244 and JP-A-5-188633, in a toner containing organic resin fine particles, the organic resin fine particles are vapor-deposited / plated with a metal or conductive oxide is added as necessary. Although there is a description about surface treatment of a metal oxide such as zinc by a method such as ion adsorption / external addition, there is no description of a specific embodiment here either, and the structure of the present invention is completely different. Is.

[0035]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a toner, an image forming method and an image forming apparatus which solve the above problems of the prior art.

The object of the present invention is to be less sensitive to the environment,
It is an object of the present invention to provide a toner having stable charging performance, suppressing fog generation even after long-term use, and having high transferability. Further, the present invention provides an image forming method and an image forming apparatus in which the transfer residual toner is small, the toner fusion on the surface of the photoconductor and the contamination of the charging member are suppressed, and the image defects are less likely to occur even after long-term use. It is in.

[0037]

The present invention provides a toner containing at least a binder resin and a colorant, the toner having toner particles and fine particles and having an average circularity of 0.9.
50 to 0.995, the fine particles are tin oxide fine particles containing a tungsten element, and the tin element (S
Molar ratio (Sn /) of tungsten element (W) to n)
W) is 0.001 or more and 0.3 or less.

The present invention comprises a charging step of applying a voltage to a charging member to charge an image carrier, an exposure step of forming an electrostatic latent image on the image carrier charged by exposure, and a toner carrier. A developing step of transferring the toner carried on the electrostatic latent image held on the surface of the image carrier to form a toner image, and a toner image formed on the image carrier as a transfer material. In the image forming method including at least a transfer step of electrostatically transferring, the toner has toner particles and fine particles containing at least a binder resin and a colorant, and has an average circularity of 0.950 to 0.995. The fine particles are tin oxide fine particles containing tungsten element, and have a molar ratio (Sn / W) of tungsten element (W) to tin element (Sn) of 0.001 or more and 0.3 or less. An image forming apparatus using the image forming method and the image forming method comprising and.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of intensive studies made by the present inventors on the homogenization and stabilization of charging of a toner up to now, toner particles containing at least a binder resin and a colorant, and a toner having fine particles are used. The fine particles are tin oxide fine particles containing a tungsten element, and have a molar ratio (W / Sn) of the tungsten element (W) to the tin element (Sn) of 0.001 or more and 0.3 or less. And the average circularity of the toner is 0.950 to
When the toner characterized by being 0.995 is used in the image forming method and the image forming apparatus, it is extremely effective in uniformizing and stabilizing the charging property of the toner, and is excellent in transferability, and further, The present invention has been found to suppress the toner fusion to the surface of the photoconductor and the abrasion of the photoconductor surface, and to stably obtain a high-definition image free from fog and other image defects even after long-term use. Is.

This has been difficult to achieve in the case of using a toner having conductive fine particles which is generally used conventionally.

The reason for this is that the conventional conductive fine particles have insufficient environmental stability of resistance, so that the triboelectrification property of the toner in various environments is insufficiently uniform. <1> Toner of the Present Invention The toner of the present invention contains toner particles and fine particles containing at least a binder resin and a colorant, and has an average circularity of 0.
It is 950 to 0.995. The fine particles contained in the toner are tin oxide fine particles having a molar ratio (W / Sn) of tungsten element (W) to tin element (Sn) of 0.001 or more and 0.3 or less.

If W / Sn is less than 0.001, the effect of containing W element may be drastically reduced, and the humidity dependence of the resistance value may be particularly exhibited. On the contrary, if it exceeds 0.3, the tin oxide crystal strength is increased. May occur and the mechanical strength may decrease.

In the present invention, the method for producing fine particles includes, for example, a method in which a tin salt compound solution and a tungsten salt compound solution are mixed, hydrolyzed, and then fired, and a tungsten salt compound solution is an aqueous tin oxide slurry. And the like, followed by aging while being hydrolyzed and then firing. After firing, fine particles are obtained by crushing, classification and the like.

Examples of tin salt compounds used in the production of tin oxide fine particles include tin chloride (first and second), tin oxychloride, tin stannate, potassium stannate, sodium stannate, and organic tin compounds (for example, tin alkoxide). Compounds) and the like.

Examples of the tungsten salt compound used for producing the tin oxide fine particles include tungsten chloride, tungsten oxychloride, tungstic acid, sodium tungstate, potassium tungstate, calcium tungstate, and an organic tungsten compound.

For the firing, a tunnel kiln, a rotary kiln, an electric furnace, a muffle furnace, a reduced pressure dryer or the like can be used. As the firing atmosphere, in addition to the air atmosphere, an oxidizing atmosphere in which the oxygen partial pressure is adjusted if necessary, a reducing atmosphere in which hydrogen gas or the like is introduced, an inert atmosphere in which an inert gas is introduced, and the like can be adopted.

In the present invention, the resistance of fine particles is 1 × 10 5.
⁹It is preferably Ωcm or less, more preferably 1
× 10²Ωcm or more 1 × 10⁹Ωcm or less, and
Preferably 1 × 10²Ωcm or more 1 × 10⁷Below Ωcm
is there. 1 x 10⁹Resistance fluctuations due to humidity above Ωcm
Is likely to occur, which is not preferable. Also, 1 × 10 ²
If it is less than Ωcm, whitening may be impaired in manufacturing.
It

The fine particles in the present invention preferably have a volume average particle diameter of 0.1 μm or more and less than 5 μm. It is more preferably 0.1 μm or more and less than 3 μm. 0.1μ
If it is less than m, electrostatic cohesion increases, and dispersibility may decrease in the step of incorporating the toner into the toner, making it difficult to control the abundance ratio of fine particles on the toner surface. When the particle size is 5 μm or more, the mixing / dispersing property in the toner may be deteriorated, the triboelectric charging property may become nonuniform, and the inside of the machine may be contaminated due to scattering from the toner.

In the present invention, the fine particles are preferably present on the toner surface. At that time, it is 0.
It is preferable that the toner is present on the toner surface in a ratio of 3 or more, and more preferably 1.0 or more and 5 per toner.
0.0 or less. If it is less than 0.3, the effect of improving the fluidity of the toner may be deteriorated, and the triboelectrification distribution may become broad. If the number exceeds 50.0, the triboelectric chargeability may decrease.

In the present invention, the average particle diameter (T) of the toner
The ratio (S / T) of the average particle size (S) of the fine particles to
It is preferably 0.5 or less. More preferably 0.
It is 3 or less and 0.01 or more. Here, the average particle size (S,
T) is a number average particle diameter of circle equivalent diameters obtained by directly measuring the particle diameters of the fine particles and the toner with a scanning microscope or the like in the same manner as the method of measuring the abundance ratio of the fine particles described below. is there. The toner of the present invention has an average circularity of 0.9.
The range of 50 to 0.995 is also one of the embodiments required for the present invention.

The circularity in the present invention is an index showing the degree of unevenness of particles, and when the particles are perfectly spherical, 1.
The circularity has a smaller value as the surface shape becomes more complicated.

In order to reduce the amount of toner adhered to the non-image area on the image bearing member and the amount of transfer residual toner, it is necessary that the chargeability of the toner particles is sufficient and uniform. Furthermore, when a toner having a small particle size is used from the viewpoint of high image quality, the adhesive force of the toner particles increases, so the shape of the toner particles also greatly affects the toner adhesion to the non-image area on the electrostatic image carrier. Exert. That is, as the toner particles are closer to a sphere and the shapes are more uniform, the adhesion area of the particles is reduced, the toner adhesion to the non-image portion on the electrostatic image carrier and the transfer residual toner amount are reduced, and the effect of the present invention. Is further improved, and high image quality and durability stability are achieved.

In the present invention, the average circularity of the toner is 0.950 or more, preferably 0.970 or more. At this time, the effects of the present invention are further improved, and high image quality and high stability are achieved. A toner having an average circularity of 0.970 or more has almost no edge portion on the surface of the toner particles, and therefore the photosensitive member surface is not scratched at the pressure contact portion between the charging member and the photosensitive member. It may also be suppressed.

In the present invention, the standard deviation of the toner circularity distribution is preferably less than 0.040. The standard deviation of the circularity distribution of the toner represents the variation in the circularity among the toner particles, and when the value is 0.040 or more,
Due to the presence of toner particles having a non-uniform shape, problems such as toner fusion to the photoconductor and abrasion of the photoconductor surface are likely to occur during long-term use, which is not preferable. In particular, in a contact charging type image forming method, it tends to become a more prominent problem. Further, these effects also become prominent even in an image forming method including a contact transfer step in which voids during transfer tend to occur.

As the colorant contained in the toner of the present invention, a magnetic or non-magnetic inorganic compound, known pigments and dyes can be used.

As the colorant used when the toner is a black toner, for example, ferromagnetic metal particles such as cobalt and nickel, or chromium, manganese,
Examples include copper, zinc, aluminum, alloys containing rare earth elements, magnetite, hematite, titanium black, nigrosine dye / pigment, carbon black, and phthalocyanine.

As the colorant used when the toner is a yellow toner, for example, yellow lead, cadmium yellow, mineral fast yellow, navel yellow, naphthol yellow S, Hansa yellow G, permanent yellow NCG, benzidine yellow condensed azo compound,
Examples include isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, allylamide compounds and the like. Specifically, C.I. I. Pigment Yellow 1
2, 13, 14, 15, 17, 62, 74, 83, 9
3, 94, 95, 109, 110, 111, 128, 1
29, 147, 168 and the like.

As the colorant used when the toner is a magenta toner, for example, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, Examples thereof include perylene compounds. Specifically, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 1
0, 11, 12, 13, 14, 15, 16, 17, 1
8, 19, 21, 22, 23, 30, 31, 32, 3
7, 38, 39, 40, 41, 48, 49, 50, 5
1, 52, 53, 54, 55, 57, 58, 60, 6
2, 63, 64, 68, 74, 81, 83, 87, 8
8, 89, 90, 93, 94, 95, 109, 110,
111, 112, 114, 122, 123, 128, 1
29, 146, 147, 150, 163, 168, 18
4, 202, 206, 207, 209, 238; C.I.
I. Pigment Violet 19; C.I. I. Butt red 1, 2, 10, 13, 15, 23, 29, 35 and the like.

Examples of the colorant used when the toner is a cyan toner include a copper phthalocyanine compound and its derivative, a basic dye lake compound, and the like.
Specifically, C.I. I. Pigment Blue 1, 7, 15,
15: 1, 15: 2, 15: 3, 15: 4, 60, 6
It is 2, 66 mag.

In the present invention, it is preferable that the colorant is a magnetic powder mainly composed of magnetite, and that the magnetic powder is not substantially exposed on the toner surface. When using a toner whose magnetic powder is exposed on the surface of the toner,
It is not preferable because it easily causes a problem such as abrasion of the surface of the photoreceptor. Further, in the case of a toner in which the magnetic powder is not substantially exposed on the toner surface, the effect of improving the charging characteristics by adding the fine particles in the present invention synergistically increases, and the environmental stability of the charging characteristics of the toner is improved. Improve dramatically.

When a magnetic toner containing a magnetic powder whose colorant is mainly magnetite is produced, it is preferable to use the magnetic powder whose surface is hydrophobized. In this case, the dispersibility of the magnetic powder in the toner binder resin can be improved, and even when a large amount of the magnetic powder is exposed on the toner particle surface, the surface of the magnetic powder is sufficiently If it is uniformly hydrophobized, it becomes difficult to impair the charging performance of the toner under any environment.

Therefore, various methods have been proposed for making the surface of the magnetic powder hydrophobic. However, it has been difficult to obtain a magnetic powder sufficiently and uniformly hydrophobized by the conventional methods. In addition, when a large amount of the treating agent or the like or a highly viscous treating agent is used, the degree of hydrophobicity certainly increases, but coalescence of particles occurs, and compatibility of hydrophobicity and dispersibility is not always achieved. Was not achieved.

In general, the surface of iron oxide used as magnetic powder has hydrophilicity, and therefore hydrophilic iron oxide must be hydrophobized in order to obtain hydrophobic iron oxide. However, in the conventional surface treatment method, the uniformity of hydrophobicity is insufficient, and when such iron oxide is used, the toner tends to change its chargeability depending on humidity and the like, and lacks stability.
Even when the fine particles of the present invention are used, a part of the effect of improving the charging characteristics is likely to be impaired.

In the present invention, it is preferable that the magnetic iron oxide such as magnetite used as the magnetic powder has a high level of hydrophobic homogeneity. As a method of uniformly and sufficiently hydrophobizing iron oxide, for example, when hydrophobizing, a method of hydrolyzing a coupling agent while dispersing iron oxide in a water-based medium to have a primary particle size and surface-treating There is. Compared with the treatment in the gas phase, the hydrophobic treatment method in an aqueous medium is less likely to cause coalescence of iron oxide particles with each other, and the electrostatic repulsion action between iron oxide particles due to the hydrophobic treatment works, and iron oxide is Since the surface is treated in the state of almost primary particles, a highly uniform hydrophobization is achieved.

The method of treating the surface of iron oxide while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent such as chlorosilanes and silazanes that generate gas, and further, Up to now, iron oxide particles have easily coalesced with each other in the gas phase, and a highly viscous coupling agent, which has been difficult to treat satisfactorily, can now be used, and the effect of hydrophobization is great.

Examples of coupling agents that can be used include silane coupling agents and titanium coupling agents. A silane coupling agent is more preferably used and is represented by the following general formula (I).

[0067]

R _m SiY _n (I) (In the formula, R represents an alkoxy group, m represents an integer of 1 to 3, and Y represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group, or a methacryl group. And n is an integer of 1 to 3, provided that m + n = 4.) As a specific compound represented by the general formula (I),
For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, Trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, n
Mention may be made of octadecyltrimethoxysilane.

In particular, it is preferable to hydrophobize iron oxide in an aqueous medium using an alkyltrialkoxysilane coupling agent represented by the following general formula (II).

[0069]

## STR2 ## _{C p H2 p + 1 -Si- (} OC q H 2q + 1) 3 (II) ( wherein, p represents an integer of 2 to 20, q is an integer of 1-3.) When p in the general formula (II) is smaller than 2, the hydrophobic treatment is easy, but it is difficult to impart sufficient hydrophobicity, and when p is larger than 20, the hydrophobicity is sufficient. However, coalescence of the iron oxide particles increases, and it becomes difficult to sufficiently disperse the iron oxide particles in the toner. On the other hand, when q is larger than 3, the reactivity of the silane coupling agent is lowered and it becomes difficult to sufficiently perform the hydrophobization.

In particular, alkyl in which p is an integer of 2 to 20 (more preferably an integer of 3 to 15) and q is an integer of 1 to 3 (more preferably an integer of 1 or 2). It is preferable to use a trialkoxysilane coupling agent.

The treatment amount is 0.05 to 20 parts by mass, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of iron oxide.

In the present invention, the aqueous medium is a medium containing water as a main component. Specifically, water itself as an aqueous medium, water with a small amount of a surfactant added,
Examples include water to which a pH adjuster is added and water to which an organic solvent is added. The surfactant is preferably a nonionic surfactant such as polyvinyl alcohol. The surfactant is preferably added in an amount of 0.1 to 5 mass% with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid.

Stirring when hydrophobizing iron oxide is carried out, for example, by a mixer having stirring blades (specifically, a high shear mixing device such as an attritor or TK homomixer), and the iron oxide fine particles are mixed with an aqueous medium. Among them, it is preferable to sufficiently perform the process so that primary particles are formed.

Since the surface of the iron oxide obtained as described above is uniformly subjected to the hydrophobic treatment, when it is used as a toner material, the dispersibility in the toner is very good, and the iron oxide from the toner surface is also excellent. There is no exposure.

Therefore, by using such iron oxide, the ratio of the iron element content (B) to the carbon element content (A) present on the surface of the toner (A) measured by X-ray photoelectron spectroscopy ( It is possible to obtain a toner having B / A) of less than 0.001. By using such toner, the effect of the present invention is further enhanced. Furthermore, (B
By setting / A) to less than 0.0005, the effect of the present invention is further improved.

The following method can be given as a specific method for producing iron oxide whose surface is uniformly and sufficiently hydrophobized as described above.

An aqueous solution containing ferrous hydroxide is prepared by adding an equivalent amount or an equivalent amount or more of alkali such as sodium hydroxide to the aqueous ferrous sulfate solution. Air is blown while maintaining the pH of the prepared aqueous solution at pH 7 or higher (preferably pH 8 to 10), and the oxidation reaction of ferrous hydroxide is carried out while heating the aqueous solution to 70 ° C. or higher to obtain the core of magnetic iron oxide particles. First, a seed crystal that becomes

Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals, based on the amount of alkali added previously. While maintaining the pH of the solution at 6 to 10, the reaction of ferrous hydroxide is promoted while air is blown in, and magnetic iron oxide particles are grown around the seed crystal. Although the pH of the liquid shifts to the acidic side as the oxidation reaction progresses, it is preferable that the pH of the liquid is not less than 6. At the end of the oxidation reaction, adjust the pH of the solution, stir it sufficiently so that the magnetic iron oxide becomes primary particles, add a coupling agent, stir and mix thoroughly, and after stirring, filter, dry and lightly disintegrate. By doing so, hydrophobically treated magnetic iron oxide particles are obtained. Alternatively,
After the completion of the oxidation reaction, the iron oxide particles obtained by washing and filtering are redispersed in another aqueous medium without being dried, and then the pH of the redispersion liquid is adjusted and the silane cup is sufficiently stirred. Coupling treatment may be performed by adding a rigging agent.

In any case, it is important to make the untreated iron oxide particles produced in the aqueous solution hydrophobic in the state of the water-containing slurry before the drying step. This is because if untreated iron oxide particles are dried as they are, coalescence due to agglomeration of the particles is unavoidable, and even if wet-hydrophobizing treatment is performed on such agglomerated powder, a uniform hydrophobizing treatment is performed. This is because it is difficult to achieve B / A <0.001 with a toner using such surface-treated iron oxide.

As the above-mentioned ferrous sulfate, iron sulfate generally produced as a by-product in the production of titanium by the sulfuric acid method and iron sulfate produced as a result of cleaning the surface of a steel sheet can be used. Further, a ferrous salt such as iron chloride can be used instead of ferrous sulfate.

In the method for producing magnetic iron oxide by the aqueous solution method, generally, an iron concentration of 0.5 to 2 mol / liter is used in view of preventing the viscosity from increasing during the reaction and the solubility of iron sulfate. Generally, the thinner the concentration of iron sulfate, the finer the particle size of the product tends to be. In addition, during the reaction, the larger the amount of air and the lower the reaction temperature, the easier the particles become.

Japanese Patent Publication No. 60-3181 also discloses a method for producing a magnetic polymerized toner containing magnetic powder whose surface is wet-treated with a silane coupling agent. However, it describes the wet surface treatment of dry powdery untreated magnetic powder with a silane coupling agent. Since such untreated dry magnetic powder cannot avoid coalescence of particles due to primary agglomeration during drying, it is difficult to evenly hydrophobize individual magnetic powder even after wet surface treatment. . Therefore, even if a polymerized toner is manufactured using such surface-treated magnetic powder, B / A <
Achieving 0.001 is difficult.

Iron oxides used as magnetic powder in the toner of the present invention include phosphorus, cobalt, nickel,
It may contain elements such as copper, magnesium, manganese, aluminum and silicon, and contains triiron tetraoxide and γ-iron oxide as main components, and these may be used alone or in combination of two or more. These iron oxides have a BET specific surface area by the nitrogen adsorption method of preferably ² to 30 m ² / g, especially 3
It is preferably about 28 m ² / g and has a Mohs hardness of 5 to 7.

The shape of iron oxide is octahedron, 6
Although it has a surface, a sphere, a needle, a scale, and the like, a material having a small anisotropy such as an octahedron, a hexahedron, a sphere, or an amorphous shape is preferable for increasing the image density. Such a shape can be confirmed by SEM or the like. As the particle size of iron oxide, the volume average particle size is 0.1 to 0.3 in the measurement of the particle size of particles having a particle size of 0.03 μm or more.
40% by number of particles having a size of μm and 0.03 to 0.1 μm
Below, 10% by number or less of particles of 0.3 μm or more is preferable.

When an image is obtained from a toner using iron oxide having a volume average particle size of less than 0.1 μm, the tint of the image shifts to reddish, the blackness of the image is insufficient, and the halftone image is redder. Generally, it is not preferable because the taste tends to be felt strongly. Further, since the surface area of iron oxide increases, the dispersibility decreases, and the energy required for production increases, which is not efficient. Further, the effect of iron oxide as a coloring agent becomes weak, and the density of an image may be insufficient, which is not preferable.

On the other hand, the volume average particle size of iron oxide is 0.3 μm.
If it exceeds, since the mass per particle becomes large, the probability of being exposed to the toner surface due to the effect of the difference in specific gravity with the binder resin at the time of manufacturing increases, or the possibility of wear of the manufacturing apparatus becoming significant, etc., It is not preferable because the sedimentation stability of the dispersion is lowered.

If the number of particles of iron oxide having a particle diameter of 0.1 μm or less exceeds 40% by number in the toner, the surface area of the iron oxide increases and the dispersibility decreases, and agglomerates are apt to occur in the toner, and the toner is charged. It is preferably 40% by number or less, because the possibility of impairing the properties and the decrease in coloring power increases. Furthermore, when the content is 30% by number or less, the tendency becomes smaller, which is more preferable. 0.03μ
Iron oxide having a particle size of less than m has a small stress due to its small particle size during toner production, and therefore has a low probability of appearing on the surface of the toner particles. Further, even if it is exposed on the surface of the particles, it hardly acts as a leak site, and there is practically no problem. Therefore, in the present invention, 0.03 to
Focusing on particles of 0.1 μm, the number% thereof is defined.

Further, when the number of particles of 0.3 μm or more in iron oxide exceeds 10% by number, the coloring power tends to decrease, and the image density tends to decrease. Since it is too small, it is probabilistically difficult to allow the toner particles to exist near the surface of the toner particles and to contain a uniform number in each toner particle, which is not preferable. More preferably 5
It is preferable that the number is less than or equal to%.

In the present invention, with respect to iron oxide, the iron oxide production conditions are set so that the above-mentioned particle size distribution conditions are satisfied,
It is preferable to use the one whose particle size distribution has been adjusted in advance by pulverization and classification. As a classification method, for example,
A means using sedimentation separation such as centrifugation or thickener, or a means such as a wet classification device using a cyclone is suitable.

The volume average particle size and particle size distribution of iron oxide are determined by the following measuring methods. 100 particles of iron oxide particles in the field of view were measured by a transmission electron microscope (TEM) with a photograph at a magnification of 30,000, and the projected areas of the particles were measured. The equivalent diameter of a circle equal to the area is obtained as each particle size. Further, based on the result, the volume average particle diameter is calculated and 0.03 to
The number% of particles of 0.1 μm and particles of 0.3 μm or more is calculated. The particle size is measured for particles having a particle size of 0.03 μm or more. It is also possible to measure the particle size with an image analysis device.

The volume average particle size and particle size distribution of iron oxide in the toner particles are determined by the following measuring method.

After sufficiently dispersing the toner particles to be observed in the epoxy resin, and curing the cured product in an atmosphere at a temperature of 40 ° C. for 2 days, a cured product obtained by using a microtome was used as a flaky sample to obtain a transmission electron microscope. In (TEM), the projected areas of the particle sizes of 100 iron oxide particles in the field of view were measured with a photograph at a magnification of 10,000 to 40,000 times, and the equivalent diameter of a circle equivalent to the projected area of each measured particle was determined. Calculated as the particle size of iron oxide. Furthermore, based on the result, 0.03 to 0.1
The number% of particles of μm and particles of 0.3 μm or more is calculated.

Furthermore, in addition to iron oxide, other coloring agents may be used in combination. Examples of the coloring material that can be used in combination include magnetic or non-magnetic inorganic compounds, known dyes and pigments. Specifically, for example, ferromagnetic metal particles such as cobalt and nickel, or chromium, manganese, copper,
Examples include zinc, aluminum, alloys containing rare earth elements, hematite, titanium black, nigrosine dye / pigment, carbon black, and phthalocyanine. These may also be used by treating the surface.

In the toner of the present invention, the minimum value of the distance between the iron oxide and the toner surface in the cross-sectional observation of the toner using a transmission electron microscope (TEM), where C is the particle diameter of the toner (projected area equivalent diameter). If the number of toners satisfying the relationship of D / C ≦ 0.02 is 50% or more, the effect of the present invention is more significant. Further, it is more preferable that the number of toners satisfying the relationship of D / C ≦ 0.02 is 65% or more, and 7
5% or more is more preferable.

When the number of toners satisfying the relationship of D / C ≦ 0.02 is less than 50%, magnetic powder is completely present at least outside the boundary line of D / C = 0.02 in the majority of the toners. Will not do. If such particles are assumed to be spherical, at least 11.5% of the space where the magnetic powder does not exist is present on the surface of the toner when one toner is the entire space. In reality, the magnetic powder is not evenly arranged at the closest position to form an inner wall inside the toner, so it is clear that the amount is 12% or more. In the toner composed of such particles, the various problems described above are likely to occur.

B / A <0.001 is satisfied, and D / C ≦
The toner whose number of toners satisfying the relationship of 0.02 is 50% or more means that the magnetic powder is localized on the toner surface or, conversely, is extremely encapsulated and unevenly distributed inside the toner. It is a toner in which the magnetic powder is substantially evenly dispersed in the toner, but the exposure of the magnetic powder to the toner surface is suppressed, rather than the toner that is present.

When the dispersed state of the magnetic powder is not uniform, it is difficult to satisfy the requirements of the present invention.

In the present invention, when the toner is a magnetic toner, the effect of the present invention is further improved when a magnetic toner in which magnetic powder is hardly exposed on the surface of the toner particles is used. Thus, even in the image forming method in which the toner is pressed against the surface of the image carrier, the surface of the image carrier is hardly scraped, and it is possible to significantly reduce the scraping of the image carrier and the fusion of the toner for a long period of time. .

The magnetic powder used in the toner of the present invention is
It is preferable to use 10 to 200 parts by mass, and more preferably 20 to 180 parts by mass, relative to 100 parts by mass of the binder resin. If the content of the magnetic powder is less than 10 parts by mass, the coloring power of the toner is poor and it is difficult to suppress fog.
On the other hand, when the amount exceeds 200 parts by mass, the coercive force due to the magnetic force on the toner carrier is increased, the developability is lowered, and it is difficult to uniformly disperse the magnetic powder to each toner particle, and the fixability is improved. Tends to decline.

In the toner of the present invention, the weight average particle diameter is preferably 2 to 10 μm. When the weight average particle diameter of the toner exceeds 10 μm, the reproducibility of the fine dot image is deteriorated, and thus the charging stability of the toner in a harsh environment cannot be sufficiently exhibited. On the other hand, when the weight average particle diameter of the toner is smaller than 2 μm, the fluidity of the toner becomes remarkably low even when the special iron oxide of the present invention is used, and problems such as fogging and lightening of density due to poor charging tend to occur. Become.

That is, in the toner of the present invention, the remarkable effects such as the improvement of the charging stability and the fluidity as compared with the conventional example appear on the image when the weight average particle diameter is 2 to 10 μm. . The weight average particle diameter is more preferably 3 to 10 μm.
And further, in terms of further improving the image quality, 3.
It is preferably 5 to 8.0 μm.

Next, a method for producing the toner of the present invention will be described.

The toner particles in the toner are partially or wholly obtained by a polymerization method. The toner of the present invention can be manufactured by a pulverization method. However, in the pulverization method, when controlling the average circularity of the toner or the standard deviation of the circularity distribution, mechanical, thermal or some special treatment is performed. It is necessary to do it. Therefore, it is preferably produced by the suspension polymerization method.

In the production of toner by the suspension polymerization method, iron oxide is generally added to the toner composition, that is, the polymerizable monomer.
Coloring agents, waxes, plasticizers, binders, charge control agents, cross-linking agents, and other components necessary for toner, and other additives, such as organic solvents that are added to reduce the viscosity of the polymer produced by the polymerization reaction, dispersion Add a suitable agent, and suspend the monomer system uniformly dissolved or dispersed by a homogenizer, a ball mill, a colloid mill, an ultrasonic disperser, or another disperser in an aqueous medium containing a dispersion stabilizer. . At this time, it is better to use a high-speed stirrer or a high-speed disperser such as an ultrasonic disperser to immediately obtain the desired toner particle size.
The resulting toner particles have a sharp particle size. Regarding the timing of addition of the polymerization initiator, it may be added at the same time when other additives are added to the polymerizable monomer, or may be mixed immediately before being suspended in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or a solvent may be added immediately after granulation and before starting the polymerization reaction.

After granulation, stirring may be carried out using an ordinary stirrer to such an extent that the particle state is maintained and the particles are prevented from floating and settling. When the toner of the present invention is produced by the suspension polymerization method, the following are examples of the polymerizable monomer that can serve as the binder resin. Styrene-based monomers such as styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-ethylstyrene; methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid Isobutyl, acrylic acid n-
Acrylic esters such as propyl, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-methacrylate. Methacrylic acid such as propyl, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate. Esters; acrylonitrile, methacrylonitrile, acrylamide and the like.

These monomers may be used alone or in combination. Among the above-mentioned monomers, it is preferable to use styrene or a styrene derivative alone or in combination with other monomers, from the viewpoint of developing characteristics and durability of the toner.

Further, it is also one of the preferable usage forms that the toner of the present invention contains 0.5 to 50% by mass of wax with respect to the binder resin. Usually, the toner image is transferred onto a transfer material in a transfer process, and then the toner image is fixed onto the transfer material by energy such as heat and pressure, and a semi-permanent image is obtained. As a fixing method at this time, a heat roll type fixing is generally often used, but as described above, if a toner having a weight average particle diameter of 2 to 10 μm is used, a very high-definition image can be obtained. When the transfer material such as paper is used, the toner particles having a small particle diameter enter the gaps between the fibers of the paper, the heat is not sufficiently received from the heat fixing roller, and the low temperature offset is likely to occur.
However, in the toner of the present invention, by containing an appropriate amount of wax as a release agent, it is possible to prevent abrasion of the photoconductor while achieving both high resolution and offset resistance.

As waxes usable in the toner of the present invention, petroleum waxes such as paraffin wax, microcrystalline wax, petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof by Fischer-Tropsch method, Polyolefin wax represented by polyethylene and its derivatives, natural wax such as carnauba wax and candelilla wax and its derivatives are included. The derivatives here include oxides, block copolymers with vinyl monomers, and graft modified products. Further, higher aliphatic alcohols, fatty acids such as stearic acid and palmitic acid or compounds thereof, acid amide wax, ester wax, ketone, hydrogenated castor oil and its derivatives, plant wax, animal wax can also be used.

Among these wax components, those having an endothermic peak by differential thermal analysis of 40 to 110 ° C., that is, in the DSC curve measured by a differential scanning calorimeter, the maximum in the region of 40 to 110 ° C. at the time of temperature rise. Those having an endothermic peak are preferable. Further, those having a maximum endothermic peak in the region of 45 to 90 ° C. are preferable.

By having the maximum endothermic peak in the above temperature range, releasability can be effectively exhibited while greatly contributing to low temperature fixing. If this maximum endothermic peak is less than 40 ° C., the self-cohesive force of the wax component will be weakened, and as a result, the high temperature offset resistance will deteriorate. on the other hand,
If this maximum endothermic peak exceeds 110 ° C., the fixing temperature becomes high and low-temperature offset easily occurs, which is not preferable. Further, when granulating / polymerizing in an aqueous medium to directly obtain a toner by a polymerization method, if the maximum endothermic peak temperature is high, problems such as precipitation of a wax component mainly during granulation occur, which is not preferable.

The maximum endothermic peak temperature of the wax component is measured according to "ASTM D 3418-8". For the measurement, for example, Perkin Elmer DSC-7 is used. The melting point of indium and zinc is used to correct the temperature of the device detection unit, and the heat of fusion of indium is used to correct the amount of heat. An aluminum pan is used as a measurement sample, an empty pan is set as a control, and measurement is performed at a temperature rising rate of 10 ° C./min.

The content of the above wax component in the toner of the present invention is preferably in the range of 0.5 to 50 mass% with respect to the binder resin. When the content of the wax component is less than 0.5% by mass, the low-temperature offset suppressing effect is poor, and when it exceeds 50% by mass, the long-term storability is deteriorated, and
The dispersibility of other toner materials deteriorates, which leads to deterioration of toner fluidity and deterioration of image characteristics.

In the present invention, a resin may be added to the monomer system for polymerization. For example, hydrophilic functional groups such as amino groups, carboxylic acid groups, hydroxyl groups, sulfonic acid groups, glycidyl groups, and nitrile groups that cannot be used because monomers are water-soluble and dissolve in aqueous suspension to cause emulsion polymerization. When it is desired to introduce the contained monomer components into the toner, a random copolymer of these and a vinyl compound such as styrene or ethylene,
It can be used in the form of a copolymer such as a block copolymer or a graft copolymer, or in the form of a polycondensate such as polyester or polyamide, or a polyaddition polymer such as polyether or polyimine. When such a high molecular weight polymer containing a polar functional group is coexisted in the toner, the wax component is phase-separated, the inclusion becomes stronger, and the toner having good offset resistance, blocking resistance, and low temperature fixing property is obtained. Obtainable. The amount used is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer.
If the amount used is less than 1 part by mass, the effect of addition is small, while 20
When it is used in excess of parts by mass, it becomes difficult to design various physical properties of the polymerized toner. The average molecular weight of the high molecular weight polymer containing these polar functional groups is preferably 3000 or more. Molecular weight less than 3000, especially 2000
In the following, since the present polymer tends to concentrate near the surface,
It is not preferable because the developability and blocking resistance are likely to be adversely affected. Further, when a polymer having a molecular weight different from the molecular weight range of the toner obtained by polymerizing the monomer is dissolved in the monomer and polymerized, a toner having a wide molecular weight distribution and high offset resistance can be obtained. it can.

In the present invention, the toner may be blended with a charge control agent in order to stabilize the charging characteristics. As the charge control agent, known charge control agents can be used, but a charge control agent having a high charging speed and capable of stably maintaining a constant charge amount is particularly preferable.

Further, when the toner is produced by the direct polymerization method, a charge control agent having a low polymerization inhibitory property and substantially no solubilized product in the aqueous dispersion medium is particularly preferable. Specific compounds include metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, and dicarboxylic acids as negative charge control agents, metal salts or metal complexes of azo dyes or azo pigments, and sulfones. Polymeric compounds having an acid or carboxylic acid group in the side chain, boron compounds, urea compounds, silicon compounds,
Examples include calix arenes. Examples of the positive charge control agent include a quaternary ammonium salt, a polymer type compound having the quaternary ammonium salt in its side chain, a guanidine compound, a nigrosine compound, and an imidazole compound. It is preferable to use these charge control agents in an amount of 0.5 to 10 parts by mass based on 100 parts by mass of the polymerizable monomer. However, in the toner of the present invention, the addition of the charge control agent is not essential, and it is not always necessary to include the charge control agent in the toner by positively utilizing the triboelectric charging between the toner layer thickness regulating member and the toner carrier. There is no.

The polymerization initiator used in the toner of the present invention has a half-life of 0.5 to 30 hours at the time of the polymerization reaction, and is added in an amount of 0.5 to 20% by mass of the polymerizable monomer. By doing so, a polymer having a maximum in the molecular weight of 10,000 to 100,000 can be obtained, and the toner can be provided with desired strength and appropriate melting characteristics. Examples of the polymerization initiator include
2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1 '
-Azobis (cyclohexane-1-carbonitrile),
Azo or diazo polymerization initiators such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene Examples thereof include peroxide-based polymerization initiators such as hydroperoxide, 2,4-dichlorobenzoyl peroxide and lauroyl peroxide.

In the present invention, a crosslinking agent may be added when the toner is produced by a polymerization method, and the preferable addition amount is 0.001 to 15% by mass. A compound having two or more polymerizable double bonds is mainly used as the cross-linking agent, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diethylene. Carboxylic acid esters having two double bonds such as methacrylate and 1,3-butanediol dimethacrylate; divinyl compounds such as divinylaniline, divinyl ether, divinyl sulfide and divinyl sulfone;
And a compound having three or more vinyl groups; used alone or as a mixture.

In the suspension polymerization method for producing the toner of the present invention, known surfactants and organic / inorganic dispersants can be used as the dispersion stabilizer, and among them, the inorganic dispersant is unlikely to produce harmful ultrafine powder. Since the dispersion stability is obtained due to the steric hindrance, the stability is not easily deteriorated even when the reaction temperature is changed, the cleaning is easy, and the toner is not adversely affected. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; calcium meta silicate and calcium sulfate.
Inorganic salts such as barium sulfate; inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite and alumina.

These inorganic dispersants are used as the polymerizable monomer 10
It is preferable to use 0.2 to 20 parts by mass with respect to 0 parts by mass, alone or in combination of two or more kinds. For the purpose of producing a finer toner having a weight average particle diameter of 2 to 10 μm, 0.001 to 0.1 part by mass of a surfactant may be used in combination.

Examples of the surfactant include sodium dodecylbenzenesulfate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate,
Examples thereof include sodium oleate, sodium laurate, sodium stearate, and potassium stearate.

When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a water-insoluble calcium phosphate can be produced by mixing an aqueous solution of sodium phosphate and an aqueous solution of calcium chloride under high-speed stirring, and more uniform and fine dispersion is possible. At this time, a water-soluble sodium chloride salt is by-produced at the same time, but when the water-soluble salt is present in the aqueous medium, the dissolution of the polymerizable monomer in water is suppressed, and the ultrafine toner particles due to emulsion polymerization are generated. It is more convenient because it is less likely to occur. Since it becomes an obstacle when removing the remaining polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalt with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolving it with an acid or an alkali after completion of the polymerization.

In the polymerization step, the polymerization temperature is 40
Polymerization is carried out at a temperature of not less than 0 ° C, generally 50 to 90 ° C. When the polymerization is carried out within this temperature range, the wax to be sealed inside is precipitated by phase separation and the encapsulation becomes more complete. At the end of the polymerization reaction, it is possible to raise the reaction temperature to 90 to 150 ° C. in order to consume the remaining polymerizable monomer.

The toner of the present invention contains, as a fluidity improver,
Inorganic fine powder or hydrophobic inorganic fine powder may be mixed.

As the inorganic fine powder, silica, titania,
Known materials such as alumina can be used. For example,
Rica, so-called silicic acid fine powder, silicon halogen
A so-called dry process produced by vapor-phase oxidation of a compound or
Dry silica called fumed silica and water glass
Both so-called wet silica produced from etc. can be used
Is. Silanol on the surface and inside the fine silica powder
There are few groups, and Na ₂O, SO₃ ^-Low manufacturing residue such as
Dry silica is preferred. In dry silica
In the manufacturing process, for example, aluminum chloride, chloride
Compounding other metal halogen compounds such as titanium with silicon halogen compounds
Silica and other metal oxides
It is also possible to obtain composite fine powders of
It

In the present invention, the average primary particle size is 4 to 80.
It is preferable to add an inorganic fine powder of nm. The inorganic fine powder is added to improve the fluidity of the toner and make the toner particles evenly charged. However, the inorganic fine powder is subjected to a treatment such as a hydrophobic treatment to adjust the toner charge amount and improve the environmental stability. It is also preferable to impart the function of.

When the average primary particle size of the inorganic fine powder is larger than 80 nm, or when the inorganic fine powder having a particle size of 80 nm or less is not added, the transfer residual toner adheres to the charging member when it adheres to the charging member. It becomes easy and it becomes difficult to obtain stable and good charging characteristics. Further, good fluidity of the toner is not obtained, charge impartment to the toner particles is likely to be non-uniform, and problems such as increased fog, reduced image density, and toner scattering cannot be avoided. The average primary particle size of the inorganic fine powder is 4
When the particle size is smaller than nm, the cohesiveness of the inorganic fine powder is strengthened, and it tends to behave as a coagulant having a wide particle size distribution having a strong cohesiveness that is hard to be broken by crushing treatment instead of primary particles, and thus the development of the coagulant, Image defects are likely to occur due to damage to the image bearing member or the toner bearing member. In order to make the charge distribution of the toner particles more uniform, the average primary particle size of the inorganic fine powder is more preferably 6 to 35 nm.

In the present invention, the average primary particle diameter of the inorganic fine powder is measured by a photograph of the toner magnified by a scanning electron microscope, and further by an XM attached to the scanning electron microscope.
Measure 100 or more of the average primary particles of inorganic fine powder existing on the toner surface adhering or free while comparing the photograph of the toner mapped by the element contained in the inorganic fine powder by elemental analysis means such as A. Then, the number average particle diameter can be obtained.

The addition amount of the inorganic fine powder having an average primary particle diameter of 4 to 80 nm is 0.1 to 3.0% by mass based on the toner particles.
If the addition amount is less than 0.1% by mass, the effect is not sufficient, and if it is 3.0% by mass or more, the fixing property becomes poor.

The inorganic fine powder in the present invention is preferably one which has been subjected to a hydrophobizing treatment in view of the characteristics under a high temperature and high humidity environment. When the inorganic fine powder added to the toner absorbs moisture, the charge amount of the toner particles is remarkably reduced, and the toner tends to scatter.

As the hydrophobizing treatment agent, a silicone varnish, various modified silicone varnishes, silicone oils, various modified silicone oils, silane compounds, silane coupling agents, other organic silicon compounds, organic titanium compounds, etc. may be used alone. Alternatively, it may be used in combination.

Among them, those treated with silicone oil are preferable, and more preferably those treated with silicone oil at the same time as or after the inorganic fine powder is subjected to hydrophobic treatment with a silane compound (hexamethyldisilazane etc.). Even in a high-humidity environment, the triboelectric charge amount of the developer can be maintained high, and toner scattering can be prevented.

The treatment conditions for the inorganic fine powder include, for example, a silylation reaction with a silane compound as a first step reaction to eliminate silanol groups by chemical bonds, and a second step reaction with a silicone oil to make the surface hydrophobic. A thin film can be formed.

The above silicone oil preferably has a viscosity at 25 ° C. of 10 to 200,000 mm ² / s, more preferably 3,000 to 80,000 mm ² / s. If it is less than 10 mm ² / s, the inorganic fine powder is not stable, and the image quality tends to deteriorate due to heat and mechanical stress. If it exceeds 200,000 mm ² / s,
Uniform treatment tends to be difficult.

As the silicone oil to be used, for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene modified silicone oil, chlorophenyl silicone oil, fluorine modified silicone oil and the like are particularly preferable.

As a method of treating silicone oil,
As described above, for example, the inorganic fine powder treated with the silane compound and the silicone oil may be directly mixed by using a mixer such as a Henschel mixer, or the inorganic fine powder may be sprayed with the silicone oil. Good. Alternatively, a method may be used in which after dissolving or dispersing silicone oil in a suitable solvent, inorganic fine powder is added and mixed to remove the solvent. The method using a sprayer is more preferable in that the formation of aggregates of the inorganic fine powder is relatively small.

The amount of silicone oil to be treated was 1 for inorganic fine powder.
1 to 23 parts by weight, preferably 5 to 20 parts by weight with respect to 00 parts by weight
Good mass parts. If the amount of silicone oil is too small, good hydrophobicity cannot be obtained, and if it is too large, problems such as fogging occur.

The average primary particle size used in the present invention is 4-8.
The 0 nm inorganic fine powder preferably has a specific surface area within the range of ²⁰ to 250 m ² / g due to nitrogen adsorption measured by the BET method.

The specific surface area is determined according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics Co., Ltd.) to adsorb nitrogen gas on the sample surface and calculating the specific surface area using the BET multipoint method.

If necessary, external additives other than the fluidity improver may be added to the toner of the present invention. For example, inorganic fine particles or organic fine particles having a nearly spherical shape can be further added for the purpose of improving the cleaning property. These cleaning property improvers have a primary particle size of 30
The particles are preferably fine particles having a particle size of more than nm (preferably having a specific surface area of less than 50 m ² / g) and a primary particle size of 5
0 nm or more (preferably specific surface area less than 30 m ² / g)
Is more preferable. Examples of the cleaning property improver include spherical silica particles, spherical polymethylsilsesquioxane particles, and spherical resin particles.

In the toner of the present invention, other additives may be added within a range that does not have a substantial adverse effect, for example, lubricant powder such as Teflon (registered trademark) powder, zinc stearate powder, polyvinylidene fluoride powder and the like; or oxidation. Abrasives such as cerium powder, silicon carbide powder, and strontium titanate powder;
Anti-caking agent; organic fine particles of opposite polarity and inorganic fine particles may be added in a small amount as a developing property improver. It is also possible to use the surface of these additives with a hydrophobic treatment.

The above-mentioned external additives are 0.01 to 5 parts by mass (preferably 0.02 to 3) with respect to 100 parts by mass of the toner.
Mass part) It is better to use.

When the toner of the present invention is manufactured by a pulverization method, a known method can be used. As a known method, for example, binder resin, magnetic powder, wax, charge control agent, and in some cases components such as colorants necessary for toner and other additives are added in a mixer such as a Henschel mixer or a ball mill. After sufficiently mixing with, the mixture is melt-kneaded using a heat kneader such as a heating roll, a kneader, or an extruder, and other toner materials such as magnetic powder are dispersed or dispersed in the resins which are mutually melted. A toner can be obtained by dissolving, cooling and solidifying, pulverizing, classifying, and if necessary, surface-treating to obtain toner particles, and adding fine particles and, if necessary, inorganic fine powder and the like and mixing. Either the classification or the surface treatment may be performed first. In terms of production efficiency, it is preferable to use a multi-division classifier in the classification step.

The crushing process can be carried out by using a known crushing device such as a mechanical impact type or a jet type. In order to obtain a toner having a specific circularity according to the present invention, it is preferable that the toner is further crushed by applying heat, or a process of supplementarily applying a mechanical impact. Further, there may be used a hot water bath method in which finely pulverized toner particles (classified according to need) are dispersed in hot water, a method of passing through a hot air stream, or the like.

As a method of applying a mechanical impact force, for example, there is a method of using a mechanical impact type crusher such as a Kryptron system manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill manufactured by Turbo Kogyo Co., Ltd. Also, like devices such as Hosokawa Micron's Mechano-Fusion System and Nara Machinery's Hybridization System, etc., the toner is pressed against the inside of the casing by centrifugal force with the blades that rotate at high speed, and by the force such as compression force and friction force. A method of applying a mechanical impact force to the toner may be used.

In the case of performing a process of applying a mechanical shock,
From the viewpoint of preventing aggregation and productivity, it is preferable to set the atmospheric temperature during the treatment to a temperature near the glass transition point Tg of the toner (that is, a temperature within the range of ± 30 ° C. of the glass transition point Tg). More preferably, it is particularly effective to improve the transfer efficiency by performing the treatment at a temperature within the range of ± 20 ° C. of the glass transition point Tg of the toner.

Furthermore, the toner of the present invention is disclosed in
A method of atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in JP-A-6-13945 to obtain a spherical toner, or an aqueous organic solvent in which a monomer is soluble and the obtained polymer is insoluble To produce a toner by using a dispersion polymerization method in which a toner is directly produced by using, or an emulsion polymerization method represented by a soap-free polymerization method in which a toner is produced by directly polymerizing in the presence of a water-soluble polar polymerization initiator. It is also possible to manufacture by the method.

The binder resin used when the toner of the present invention is manufactured by a pulverization method is a homopolymer of styrene such as polystyrene or polyvinyltoluene or a substitution product thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer. Coalesce, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer,
Styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, Styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinyl ethyl ether copolymer, styrene-
Styrene-based copolymers such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer; polymethyl methacrylate, poly Butyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resin, polyester resin, polyamide resin, epoxy resin, polyacrylic acid resin, rosin, modified rosin,
Tempel resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin wax,
Carnauba wax can be used alone or in combination. In particular, styrene-based copolymers and polyester resins are preferable in terms of development characteristics, fixability and the like.

The glass transition temperature (Tg) of the binder resin is
It is preferably 50 to 70 ° C. If it is lower than 50 ° C, the storage stability of the toner tends to be low, and if it is higher than 70 ° C, the fixing property tends to be poor.

<2> Image forming method of the present invention Each step of the image forming method of the present invention will be described.

(A) Developing Step In the developing step of the image forming method of the present invention, the toner on the toner carrier and the electrostatic latent image on the image carrier (hereinafter, also referred to as "photoreceptor") are brought into contact with each other. It is preferable to use a so-called contact development method in which development is performed. Reversal development is preferably used in the contact development method.

Furthermore, it is also preferable to use a cleanerless process in which the transfer residual toner remaining on the image bearing member after the transfer step is collected by the toner bearing member.
The size of the device can be greatly reduced. At this time, at the time of development or at the time of blank before and after development, a bias of DC or AC component is applied, and the potential is controlled so that development and residual toner on the photoconductor can be collected.
It is located between the light potential and the dark potential.

An elastic roller is preferably used as the toner carrier. The surface of the elastic roller is coated with toner and brought into contact with the surface of the photoreceptor. In this case, since development is performed by an electric field acting between the photoconductor and the elastic roller facing the photoconductor surface via the toner, the surface of the elastic roller or the vicinity of the surface has a potential, and the surface of the photoconductor and the surface of the toner carrier are narrow. It is necessary to have an electric field in the gap. For this reason, the elastic rubber or the like forming the elastic roller is resistance-controlled in the medium resistance region to prevent conduction with the surface of the photoconductor to maintain the electric field, or a thin insulating layer is formed on the surface layer of the conductive elastic roller. The method of providing can also be used. Further, there is also a configuration in which a conductive resin sleeve having a surface facing the photoconductor surface coated with an insulating material is provided on a conductive elastic roller, or a conductive layer is provided on a side of the insulating elastic roller not facing the photoconductor. It is possible.

It is also possible to use a rigid roller as the toner carrier and use a flexible member such as a belt for the photosensitive member.

The resistance of the elastic roller as the toner carrier is preferably in the range of 10 ² to 10 ⁹ Ωcm. 10 ² Ω
If it is lower than cm, for example, if there is a pinhole or the like on the surface of the photoconductor 1, an overcurrent may flow. On the contrary 1
If it is higher than ⁰⁹ Ωcm, charge-up of the toner due to triboelectric charging is likely to occur and the image density is likely to be lowered.

The hardness of the elastic roller used is preferably 20 to 65 degrees (JIS A).

As the surface shape of the toner carrier, the surface roughness Ra (μm) is preferably 0.2 to 3.0. When set to fall within the above range, both high image quality and high durability can be achieved. The surface roughness Ra correlates with the toner conveying ability and the toner charging ability. When the surface roughness Ra of the toner carrier exceeds 3.0, not only is it difficult to thin the toner layer on the toner carrier, but also the chargeability of the toner is not improved, so that improvement in image quality cannot be expected. . By setting the surface roughness Ra to 3.0 or less, the toner carrying ability on the surface of the toner carrier is suppressed, the toner layer on the toner carrier is thinned, and the number of times of contact between the toner carrier and the toner is reduced. Therefore, the chargeability of the toner is also improved and the image quality is synergistically improved. On the other hand, when the surface roughness Ra is less than 0.2, it becomes difficult to control the toner coating amount.

In the contact developing method, the toner carrier may rotate in the same direction as the peripheral speed of the photosensitive member, or may rotate in the opposite direction. When the rotations are in the same direction, the peripheral speed of the toner carrier is 1.05 to 3.
It is preferable to set it to be 0 times.

If the peripheral speed of the toner carrying member is less than 1.05 times the peripheral speed of the photosensitive member, the stirring effect of the toner on the photosensitive member is insufficient, and good image quality cannot be expected. is there. Further, when developing an image that requires a large amount of toner over a large area, such as a solid black image, the amount of toner supplied to the electrostatic latent image becomes insufficient and the image density becomes low. As the peripheral speed ratio increases, the amount of toner supplied to the developing portion increases, the frequency of toner desorption with respect to the electrostatic latent image increases, and unnecessary portions are collected and applied to necessary portions. By repeating, an image faithful to the electrostatic latent image is obtained. However, if the peripheral speed ratio exceeds 3.0, conversely, in addition to the above-mentioned various problems caused by excessive charging of the toner (image density reduction due to excessive toner charge-up), mechanical stress Deterioration of the toner and adhesion of the toner to the toner carrier may occur and be promoted by the above, which is not preferable.

(B) Charging Step The charging step of the image forming method of the present invention may be a non-contact charging step using a charging means using corona discharge,
It is preferable to use a contact charging method in which the charging member is brought into contact with the photoconductor to carry out charging. In this case, it is preferable to use a charging roller as the contact charging member.

The preferable process conditions when the charging roller is used are as follows. The contact pressure of the roller is 4.9 to 490 N / m (5 to 500 g / cm), and as the charging bias, a DC voltage or a DC voltage superposed with an AC voltage is used. When a DC voltage superimposed with an AC voltage is used, AC voltage = 0.5 to 5 kVp
p, AC frequency = 50 to 5 kHz, DC voltage = ± 0.2
~ ± 5 kV is preferred.

Other charging methods include a method using a charging blade and a method using a conductive brush. Even when these contact charging methods are used, a high voltage is not required, and there is an effect that ozone generation is reduced.

As the material of the charging roller and the charging blade as the contact charging member, conductive rubber is preferable, and a releasing film may be provided on the surface thereof. Nylon-based resin, PVdF (polyvinylidene fluoride), PVdC (polyvinylidene chloride), and fluoroacrylic resin can be applied as the release coating.

(C) Transfer Step The transfer step of the image forming method of the present invention may be a non-contact transfer step using a transfer means using corona discharge,
Preferably, a contact transfer method is used in which a transfer member is brought into contact with a photoconductor through a transfer material to perform transfer.

The contact pressure of the transfer member is a linear pressure of 2.9 N.
/ M (3 g / cm) or more, more preferably 19.6 N / m (20 g / cm) or more.
If the linear pressure as the contact pressure is less than 2.9 N / m (3 g / cm), the transfer deviation of the transfer material and the transfer failure are likely to occur, which is not preferable.

An apparatus having a transfer roller or a transfer belt is used as the transfer means in the contact transfer step. FIG. 3 shows an example of the structure of the transfer roller. The transfer roller 34 includes at least the core metal 34a and the conductive elastic layer 34.
b, the conductive elastic layer is made of urethane or EPDM in which a conductive material such as carbon is dispersed, and has a volume resistance of 10 ⁶ to 10 ^6.
It is made of an elastic body of about ¹⁰ Ωcm, and a transfer bias is applied by a transfer bias power source 35.

(D) Image Carrier A photoreceptor as an image carrier used in the image forming method of the present invention will be described below.

As the photoconductor, a-Se, CdS, Zn
A photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as O ₂ , OPC (organic photoconductor), and a-Si is preferably used.

Particularly, in the present invention, it is preferable to use a photoconductor whose surface is mainly composed of a polymer binder. For example, when a protective film (protective layer) mainly composed of a resin is provided on an inorganic photoconductor such as selenium or amorphous silicon, or as a charge transport layer of a function-separated type organic photoconductor, a charge transport material and a resin are used. There are cases where a surface layer is provided, and a case where a protective layer mainly containing a resin is provided on the surface layer. It is preferable that these surface layers (or protective layers) have releasability. A surface layer (or protective layer) is a means for actually imparting releasability.
In addition, a resin having a low surface energy is used for the resin itself that constitutes the film, an additive that imparts water repellency and lipophilicity is added, and a material having high releasability is dispersed in the form of powder,
Means etc. are mentioned. For example, the introduction of a functional group such as a fluorine-containing group or a silicon-containing group into the structure of the structural unit of the resin can be mentioned. Examples of the additive that imparts water repellency and lipophilicity include a surfactant. As a powdered material having high releasability (hereinafter, also referred to as “releasing powder”), a compound containing a fluorine atom, that is, polytetrafluoroethylene, polyvinylidene fluoride, carbon fluoride, etc. Fluorine-containing resin powder of

By these means, the contact angle of water on the surface of the photoconductor can be 85 degrees or more, and the transferability of toner and the durability of the photoconductor can be further improved. The contact angle of water on the surface of the photoreceptor is preferably 90 degrees or more. In the present invention, among the above-mentioned means (1) to (4), it is preferable to disperse the powder of the fluororesin in the surface layer (or the protective layer) as described below. It is particularly preferred to use tetrafluoroethylene.

In order to contain these powders on the surface, a layer in which a releasing powder is dispersed in a binder resin is provided on the outermost surface of the photoreceptor, or the photoreceptor itself is mainly composed of resin. In the case of the organic photoreceptor described above, the releasable powder may be dispersed in the uppermost layer without providing a new surface layer. The amount of releasable powder added is based on the total amount of the surface layer.
1 to 60 mass% is preferable, and 2 to 50 mass% is more preferable. If the amount of the release powder added is less than 1% by mass, the effect of improving the transferability of the toner and the durability of the photoconductor is insufficient, and if it exceeds 60% by mass, the strength of the protective film is lowered,
It is not preferable because the amount of light incident on the photoconductor is significantly reduced.

In the image forming method of the present invention, the contact charging method in which the charging member is brought into contact with the photoconductor is the preferred charging method, but the method by corona discharge or the like in which the charging member does not contact the photoconductor is used. Since the load on the surface of the photoconductor is larger than that of the photoconductor, providing a protective layer on the surface of the photoconductor has a remarkable effect of improving durability, and is one of preferable application modes. Further, in the present invention, since it is preferable to apply the contact charging method and the contact transfer method, it is particularly effectively used for an image forming apparatus having a photoconductor having a small diameter of 50 mm or less. That is, when the diameter of the photoconductor used in image formation is small, the curvature with respect to the same linear pressure is large, and the pressure is likely to concentrate at the contact portion. Although it is considered that the same phenomenon occurs with the belt photosensitive member, the present invention is also effective for an image forming apparatus having a radius of curvature at the transfer portion of 25 mm or less.

One of the preferable modes of the photoconductor used in the present invention will be described below. The charge generation layer and the charge transport layer are applied in this order on a conductive substrate.

Examples of the conductive substrate include metals such as aluminum and stainless steel, aluminum alloys, and indium oxide.
Cylindrical cylinders and films of plastic with a coating layer of tin oxide alloy, paper impregnated with conductive particles, plastic, plastic with conductive polymers are used.

On these conductive substrates, the adhesion of the photosensitive layer is improved, the coatability is improved, the substrate is protected, the defects on the substrate are covered, the charge injection from the substrate is improved, and the electrical properties of the photosensitive layer are improved. An undercoat layer may be provided for the purpose of protection against breakage.
The subbing layer is polyvinyl alcohol, poly-N-vinylimidazole, polyethylene oxide, ethyl cellulose, methyl cellulose, nitrocellulose, ethylene-
It is formed of a material such as acrylic acid copolymer, polyvinyl butyral, phenol resin, casein, polyamide, copolymerized nylon, glue, gelatin, polyurethane and aluminum oxide. The thickness of the undercoat layer is usually 0.
It is 1 to 10 μm, preferably about 0.1 to 3 μm.

The charge generation layer comprises azo pigments, phthalocyanine pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes, selenium,
A charge generating substance such as an inorganic substance such as amorphous silicon is dispersed in a suitable binder resin and applied or vapor-deposited. Examples of the binder resin include polycarbonate resin, polyester resin, polyvinyl butyral resin, polystyrene resin, acrylic resin, methacrylic resin, phenol resin, silicone resin,
Epoxy resins and vinyl acetate resins are mentioned, and the binder resin can be arbitrarily selected from such a wide range of resins.
The amount of the binder resin contained in the charge generation layer is preferably 80% by mass or less with respect to the entire charge generation layer, and is 0 to 6
0 mass% is more preferable. Further, the film thickness of the charge generation layer is 5
It is preferably not more than μm, particularly preferably 0.05 to 2 μm.

The charge transport layer has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting them. The charge transport layer is formed by dissolving a charge transport material in a solvent together with a binder resin as necessary and applying the solution. The thickness of the charge generation layer is generally 5 to
It is 40 μm. As the charge transport material, a polycyclic aromatic compound having a structure such as biphenylene, anthracene, pyrene, or phenanthrene in the main chain or side chain, indole,
Carbazole, oxadiazole, nitrogen-containing cyclic compounds such as pyrazoline, hydrazone compounds, styryl compounds,
Examples thereof include selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide.

Further, as the binder resin for dispersing these charge transporting substances, organic light such as polycarbonate resin, polyester resin, polymethacrylic acid ester, polystyrene resin, acrylic resin, polyamide resin, poly-N-vinylcarbazole, polyvinylanthracene and the like can be used. Conductive polymers are mentioned.

Further, as the surface layer, a separate protective layer may be provided. As the resin for the protective layer, polyester, polycarbonate, acrylic resin, epoxy resin, phenol resin, or a curing agent of these resins may be used alone or in combination.
A combination of two or more species can be used. The conductive fine particles may be dispersed in the resin of the protective layer. Examples of the conductive fine particles include metals and metal oxides, preferably zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin oxide coated titanium oxide, tin coated indium oxide, antimony coated oxide. Ultrafine particles of tin, zirconium oxide, etc. may be mentioned. These conductive fine particles may be used alone or in combination of two or more. Generally, when dispersing particles in the protective layer, it is necessary that the particle size of the particles is smaller than the wavelength of the incident light in order to prevent scattering of the incident light by the dispersed particles,
The particle size of the conductive fine particles dispersed in the protective layer in the present invention is preferably 0.3 μm or less. The content of the conductive fine particles in the protective layer is preferably 2 to 90% by mass, more preferably 5 to 80% by mass, based on the total weight of the protective layer. The thickness of the protective layer is preferably 0.1 to 10 μm,
1 to 7 μm is more preferable.

The surface layer can be applied by spray coating, beam coating or dipping coating of the resin dispersion.

Next, an outline of an image forming apparatus to which the image forming method of the present invention can be applied will be specifically described with reference to FIGS. 1 and 2.

FIG. 1 shows an outline of an image forming apparatus using a cleanerless process. Reference numeral 40 is a developing device, 1 is a photoconductor, 27 is a transferred material (transfer material) such as paper, and 14 is a transfer member. Reference numeral 26 denotes a fixing pressure roller, 28 denotes a fixing heating roller, and 17 denotes a charging member which comes into contact with the photosensitive member 1 to directly charge the photosensitive member 1. A bias power supply 31 is connected to the charging member 17 so as to uniformly charge the surface of the photoconductor 1.

As shown in detail in FIG. 2, the developing device 40 contains a toner 42, and is provided with a toner carrier 4 which comes into contact with the photoconductor 1 and rotates in the direction of the arrow. A developing blade 43 as a layer thickness regulating member for imparting charge and a toner 42 are attached to the toner carrier 4, and a coating roller 41 rotating in the direction of the arrow for imparting charge to the toner by friction with the toner carrier 4. Is also equipped. A development bias power source 33 is connected to the toner carrier 4. The bias power source 32 is also connected to the coating roller 41, and the voltage is set to the negative side of the developing bias when using the negatively charging toner and to the positive side of the developing bias when using the positively charging toner. To be done.

A transfer bias power source 34 having a polarity opposite to that of the photosensitive member 1 is connected to the transfer member 14.

Here, the length in the rotational direction at the contact portion between the photosensitive member 1 and the toner carrying member 4, that is, the so-called developing nip width, is preferably 0.2 to 8.0 mm. If it is less than 0.2 mm, the amount of development is insufficient, a satisfactory image density cannot be obtained, and the transfer residual toner may be insufficiently collected. If it exceeds 8.0 mm, the toner supply amount becomes excessive, the fog suppression is likely to be deteriorated, and the abrasion of the photoconductor 1 may be adversely affected.

A so-called elastic roller having an elastic layer on its surface is preferably used as the toner carrier 4. The toner coat amount on the toner carrier 4 is 0.1 to 2.0 m.
g / cm ² is preferred. If it is less than 0.1 mg / cm ^2, it is difficult to obtain a sufficient image density, and if it is more than 2.0 mg / cm ^2, it becomes difficult to uniformly triboelectrically charge all individual toner particles, which is a cause of deterioration of fog suppression. Becomes
Furthermore, 0.2-1.4 mg / cm < ² > is more preferable.

The toner coating amount is controlled by the developing blade 43, which is in contact with the toner carrier 4 via the toner layer. The contact pressure at this time is
A preferable range is 5 to 50 g / cm. If it is less than 5 g / cm, uniform triboelectric charging becomes difficult in addition to the control of the toner coat amount, which causes deterioration of fog suppression. On the other hand, if it is more than 50 g / cm, the toner particles are excessively loaded, and the deformation of the particles and the fusion of the toner to the developing blade 43 or the toner carrier 4 are likely to occur, which is not preferable.

As the developing blade which is the layer thickness regulating member for the toner coating amount, an elastic blade for press-contacting and applying the toner can be mentioned, but a metal blade or a roller may be used instead of the elastic blade.

For the elastic blade, it is preferable to select a friction charging series material suitable for charging the toner to a desired polarity, such as silicone rubber, urethane rubber, NBR.
A rubber elastic body such as, a synthetic resin elastic body such as polyethylene terephthalate, and a metal elastic body such as stainless steel, copper, and phosphor bronze can be used. Further, it may be a complex thereof.
Further, when durability is required for the elastic blade and the toner carrier, it is preferable to use a metal elastic body to which resin or rubber is attached so as to abut on the sleeve contact portion, or a coating is applied.

Further, an organic material or an inorganic material may be added to the elastic blade, and may be melt-mixed or dispersed. For example, the chargeability of the toner can be controlled by adding metal oxides, metal powders, ceramics, carbon allotropes, whiskers, inorganic fibers, dyes, pigments and surfactants. In particular, when the elastic body of the elastic blade is a molded body such as rubber or resin, silica, alumina, titania,
Fine powder of metal oxide such as tin oxide, zirconia, zinc oxide,
It is also preferable to include carbon black, a charge control agent generally used in toners.

Furthermore, by applying a DC electric field and / or an AC electric field to the developing blade, the uniform thin layer coating property and the uniform charging property are further improved due to the loosening effect on the toner, and sufficient image density is achieved. And a high quality image can be obtained.

In FIG. 1, the charging member 17 uniformly charges the photoconductor 1 rotating in the arrow direction.

The charging member used here is a charging roller which is basically composed of a cored bar 17b at the center and a conductive elastic layer 17a forming the outer periphery thereof. The charging roller 17 is brought into contact with the entire surface of the image carrier with a pressing force, and is rotated by rotation of the photoconductor 1.

After the charging process, an electrostatic latent image corresponding to the information signal is formed on the photoconductor 1 by the exposure 23 from the light emitting element 21, and the electrostatic latent image is formed by the toner at the position where the electrostatic latent image comes into contact with the toner carrier 4. Develop and visualize. Furthermore, in the image forming method of the present invention, particularly by combining with a developing system in which a digital latent image is formed on a photoconductor, it is possible to faithfully develop a dot latent image without disturbing the latent image. . Next, the visible image is transferred onto the transferred material 27 by the transfer member 14 having the basic structure of the cored bar 14a and the conductive elastic layer 14b forming the outer periphery thereof, and the transfer toner 29 is transferred to the transferred material 27. At the same time, the transport roller 25 transports the toner to a fixing device having a fixing pressure roller 26 and a fixing pressure roller 28 to fix the toner, thereby obtaining a permanent image. The heating / pressurizing fixing means is not limited to the heat roller method, which basically has a heating roller having a heating element such as a halogen heater and an elastic pressing roller pressed against the heating roller with a pressing force. A method of heating and fixing with a heater through a film is also used.

On the other hand, the untransferred toner remaining on the photoconductor 1 without being transferred passes between the photoconductor 1 and the charging member 17, reaches the developing nip portion again, and is developed by the toner carrier 4 into the developing device. Recovered in 40.

Further, the image forming method of the present invention may be a non-contact developing method using a magnetic toner as a toner and having a cleaning means as shown in FIG.

In the developing device 140, as shown in FIG. 6, the toner carrier 102 is disposed in the vicinity of the photoconductor 100, and the gap between the photoconductor 100 and the toner carrier 102 is not shown. 5 by the photoconductor gap holding member
It is maintained at 0 to 1000 μm. In the toner carrier 102, a magnet roller 104 is fixed and arranged concentrically with the toner carrier 102. However, the toner carrier 102
Is rotatable. The magnet roller 104 is provided with a plurality of magnetic poles as shown in the figure. S1 is development and N1 is
Is a toner coat amount regulation, S2 is a toner intake / conveyance, and N2 is a toner blowout prevention. The toner is applied to the toner carrier 102 by the toner applying roller 141, adheres to the toner, and is conveyed. Elastic blade 10 as a layer thickness regulating member for regulating the amount of toner to be conveyed
3 is provided, and the toner carrier 10 of the elastic blade 103 is provided.
The amount of toner conveyed to the developing area is controlled by the contact pressure with respect to 2. In the developing area, a DC and AC developing bias is applied between the photoconductor 100 and the toner carrier 102, and the toner on the toner carrier flies onto the photoconductor 100 in accordance with the electrostatic latent image to form a visible image. Becomes

The transfer residual toner after the transfer step is cleaned by the cleaning means 116.

<3> Image Forming Apparatus of the Present Invention The image forming apparatus of the present invention uses the image forming method of the present invention, and includes the image carrier, the charging means using the charging step, and the electrostatic charge. The toner is provided using at least an electrostatic latent image forming means using the latent image forming step, a developing means using the developing step, and a transferring means using the transfer step.

<4> Method for Measuring Various Physical Property Data in the Present Invention A method for measuring various physical property data in the present invention will be described in detail below. (1) Ratio of iron element content (B) to carbon element content (A) present on toner surface (B / A) Carbon element content (A) present on toner surface of the present invention
The ratio (B / A) of the iron element content (B) to the
The surface composition is analyzed by CA (X-ray photoelectron spectroscopy analysis) and calculated.

In the present invention, the ESCA device and measurement conditions are as follows. Equipment used: PHI (Physical Electronics Industrie)
s, Inc.) 1600S type X-ray photoelectron spectrometer In the present invention, from the measured peak intensity of each element, PH
The surface atomic concentration (atomic%) is calculated using the relative sensitivity factor provided by Company I.

A toner is used as a measurement sample. When an external additive is added to the toner, the toner is washed with a solvent that does not dissolve the toner, such as isopropanol, to remove the external additive. The measurement will be performed later.

(2) Average Circularity of Toner The circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles, and in the present invention, flow type particle image analysis manufactured by Toa Medical Electronics Co., Ltd. Device FPIA-100
The particle shape is measured using 0, and the circularity is calculated by the following formula (1). Furthermore, as shown in the following formula (2),
The value obtained by dividing the total sum of the measured circularity of all particles by the total number of particles is defined as the average circularity.

[0203]

[Equation 1]

[0204]

[Equation 2]

[0205] The measuring apparatus "FPIA-1000" used in the present invention, after calculating the circularity of each particle,
In calculating the average circularity, depending on the circularity obtained, the circularity is 0.400 to 1.000 at intervals of 0.010, 0.400 or more and less than 0.410, 0.410 or more and less than 0.420. ···························· Uses a calculation method of calculating the average circularity by dividing into 61 divided areas such as 0.990 or more and less than 1.000 and 1.000, and using the center value and frequency of the dividing points.

The error between each value of the average circularity calculated by this calculation method and each value of the average circularity calculated by the above-mentioned calculation formula which directly uses the circularity of each particle is very small and substantially Therefore, in the present invention, a calculation formula that directly uses the circularity of each particle described above is used in the present invention for the reason of handling data such as shortening of calculation time and simplification of calculation calculation formula. The concept is used and a partially modified calculation method like this is used.

As a concrete measuring method of circularity, 10 m of water in which about 0.1 mg of a nonionic surfactant is dissolved.
Approximately 5 mg of the toner is dispersed in 1 to prepare a dispersion liquid, and the dispersion liquid is irradiated with ultrasonic waves (20 kHz, 50 W) for 5 minutes, and the dispersion liquid concentration is set to 5000 to 20000 particles / μl. The circularity distribution of particles having a circle equivalent diameter of 3 μm or more is measured.

The outline of the measurement is described in the catalog of FPIA-1000 issued by Toa Medical Electronics Co., Ltd. (June 1995 version), the operation manual of the measuring device and JP-A-8-136.
It is described in Japanese Patent No. 439, but is as follows.

[0209] The sample dispersion liquid is passed through the flow passage (which spreads along the flow direction) of a flat and flat transparent flow cell (thickness: about 200 µm). A strobe and a CCD camera are mounted on opposite sides of the flow cell so as to form an optical path that intersects and passes through the thickness of the flow cell. While the sample dispersion is flowing, strobe light is illuminated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. It is taken as a three-dimensional image. From the two-dimensional image area of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The circularity of each particle is calculated from the two-dimensional image projected area of each particle and the perimeter of the projected image using the above circularity calculation formula.

(3) A Coulter Counter TA-II type (manufactured by Coulter) is used as a toner particle size measuring device, and an interface (manufactured by Nikkaki) and a CX-1 personal computer (Canon) for outputting number distribution and volume distribution. (Manufactured by Mitsui Chemical Co., Ltd.) is connected, and a 1% NaCl aqueous solution is prepared using primary sodium chloride as an electrolytic solution.
For example, ISOTON R-II (manufactured by Coulter Scientific Japan Co.) can be used. As a measuring method, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) as a dispersant is added to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 measuring samples are further added.
Add mg. The electrolytic solution in which the sample was suspended was subjected to a dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the Coulter Counter TA-II type was used to measure the toner volume and number using a 100 μm aperture as an aperture. ~ 40
The volume distribution and number distribution of the μm particles are calculated. Then, a weight-based weight average particle diameter D4 (the median value of each channel is set as a representative value for each channel) calculated from the number average particle diameter (D1) volume distribution is calculated.

(4) Particle size of fine particles The particle size of fine particles is measured by measuring the particle size of 0.04 to 2000 μm by attaching a liquid module to a LS-230 type laser diffraction type particle size distribution measuring device manufactured by Coulter. Based on the obtained volume-based particle size distribution, the number% of the particles having a volume average particle size of 5 μm or more is calculated. Measurement is water 10
Add a trace amount of surfactant to ml and add 10m
After adding g and dispersing with an ultrasonic disperser for 10 minutes, the measurement is performed under the conditions that the measurement time is 90 seconds and the number of measurements is once.

(5) Resistance of fine particles The resistance of fine particles is measured as follows. A cylindrical metal cell was filled with about 0.5 g of the sample, and the electrodes were placed above and below to contact the sample, and the upper electrode had a load of 15 kgf /
Add cm ² . In this state, voltage V (100V) is applied between the electrodes.
Is applied, and the resistance (volume resistivity RV) of the present invention is measured from the current I (A) flowing at that time. When the contact area between the electrode and the sample is Scm ² and the sample thickness is Mcm, RV (unit: Ω
cm) = 100V × Scm ² / I (A) / M (cm).

(6) Number of Fine Particles Present on Toner Surface The fine particles present on the toner surface can be confirmed by, for example, direct photographing of the toner surface. That is, the toner containing the fine particles is used as a toner particle 1 by using a scanning electron microscope (SEM).
Zero particles are regarded as one aggregate, and the fine particles existing on the surface of each toner particle are measured. The fine particles are specified by using, for example, a qualitative analyzer attached to the SEM, and Sn element or W
This can be done from elemental mapping. This way 1
Measurement is performed on 0 aggregates (total of 100 toner particles), and the existence ratio of fine particles per toner particle is calculated. The structure of the tin oxide fine particles containing W element can be known by means of instrumental analysis means such as ICP, ESCA and X-ray structural diffraction.

(7) Molar Ratio of Tin Element (W) to Tin Element (Sn) in Fine Particles (Sn / W Ratio) The Sn / W ratio can be quantified by ICP, ESCA or the like. I
In the case of CP, the fine particles contained in the toner are dissolved with an acid or an alkali, and after filtering, the content of each element in the filtrate is measured, and the content of each element is converted to mol to give a molar ratio. To calculate.

(8) D / C of toner As a specific D / C measuring method by TEM, an atmosphere at a temperature of 40 ° C. after sufficiently dispersing toner particles to be observed in a room temperature curable epoxy resin A method is preferable in which the cured product obtained by curing for 2 days is observed as a flaky sample as it is or after freezing with a microtome equipped with diamond teeth.

The specific method for determining the ratio of the number of toner particles concerned is as follows. For the toner particles for determining D / C using TEM, the equivalent circle diameter was determined from the cross-sectional area in the micrograph, and the value was ± of the number average particle diameter determined by the method described below using a Coulter counter.
The particles included in the width of 10% are regarded as corresponding particles, and the minimum value (D) of the distance from the magnetic powder surface is measured for 100 corresponding particles, and D / C is obtained. Calculate the percentage of particles below 02. The micrograph at this time is preferably 10,000 to 20,000 times in magnification in order to perform highly accurate measurement. In the present invention, a transmission electron microscope (H-6 manufactured by Hitachi
00 type) as an apparatus and observed at an accelerating voltage of 100 kV, and observed and measured using a micrograph with a magnification of 10,000 times.

[0217]

[Examples] The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited thereto. The parts or% given in the examples refer to parts by weight or% by weight.

<Production of Fine Particles> Tin oxide fine particles 1 to 9 as fine particles were produced as follows. (Production Example 1 of tin oxide fine particles) Molar ratio of W and Sn (W /
Tin chloride (SnCl ₄ ·
5H ₂ O) aqueous solution and tungstic acid (H ₂ WO ₄ ) aqueous solution are mixed, while maintaining pH at 6.5 to 7.5
After heating and mixing at 0 ° C., hydrochloric acid was added, and the coprecipitate formed was filtered / dried.

The dried product was an electric furnace (600
Calcination), crushing / classification, volume average particle size = 1.
Tin oxide fine particles 1 having a size of 0 μm and a volume resistance of 1 × 10 ⁴ Ωcm were obtained.

(Production Example 2 of tin oxide fine particles) In Production Example 1 of tin oxide fine particles, W / Sn was set to 0.08, and
Further, the firing conditions and the crushing / classifying conditions were adjusted to obtain tin oxide fine particles 2 having a volume average particle size of 1.5 μm and a volume resistance of 1 × 10 ⁶ Ωcm.

(Production Example 3 of fine particles of tin oxide) In Production Example 1 of fine particles of tin oxide, W / Sn was set to 0.002, the firing conditions and the crushing / classification conditions were adjusted, and the volume average particle diameter = 0. Tin oxide fine particles 3 having a thickness of 0.2 μm and a volume resistance of 8 × 10 ⁸ Ωcm were obtained.

(Production Example 4 of tin oxide fine particles) In Production Example 1 of tin oxide fine particles, W / Sn was set to 0.27, and
Further, the firing conditions and the crushing / classifying conditions were adjusted to obtain tin oxide fine particles 4 having a volume average particle size of 0.3 μm and a volume resistance of 7 × 10 ⁶ Ωcm.

(Production Example 5 of tin oxide fine particles) In Production Example 1 of tin oxide fine particles, W / Sn was set to 0.005, and the firing conditions and the crushing / classification conditions were further adjusted to obtain a volume average particle diameter = 2. Tin oxide fine particles 5 having a volume resistance of 8 × 10 ⁵ Ωcm were obtained.

(Production Example 6 of tin oxide fine particles) Sb and Sn
The tin chloride and antimony chloride having a molar ratio (Sb / Sn) of 0.02 were hydrolyzed in hot water, and the coprecipitate was baked in an electric furnace to obtain tin oxide fine particles 6 containing antimony. The tin oxide fine particles 6 have a volume average particle diameter of 2.5 μm.
m, volume resistance = 3 × 10 ³ Ωcm, and exhibited a blackish blue color.

(Production Example 7 of tin oxide fine particles) Tin oxide fine particles not intentionally containing a different element were adjusted in particle size by crushing / classification, and volume average particle diameter = 0.6 μm, volume resistance = 5. Tin oxide fine particles 7 of × 10 ⁷ Ωcm were obtained.

(Production Example 8 of tin oxide fine particles) The tin oxide fine particles 7 were fired in a hydrogen gas atmosphere to obtain tin oxide fine particles 8 in which a part of SnO ₂ was reduced. The tin oxide fine particles 8 have a volume average particle diameter of 1.9 μm and a volume resistance of 2 × 10.
^{It was 5} Ωcm and had a black color.

(Production Example 9 of tin oxide fine particles) In Production Example 1 of tin oxide fine particles, W / Sn was set to 0.10.
Further, firing conditions and crushing / classification conditions were adjusted to obtain tin oxide fine particles 9 having a volume average particle diameter of 4.8 μm and a volume resistance of 1 × 10 ⁵ Ωcm.

The physical properties of tin oxide fine particles 1 to 9 are summarized in Table 1.

[0229]

[Table 1]

<Production of Magnetic Powder> Hydrophobized iron oxides (hydrophobic iron oxides) 1 to 6 as magnetic powders were produced as follows.

Production Example 1 of Hydrophobic Iron Oxide A ferrous sulfate aqueous solution is mixed with 1.0 to 1.1 equivalents of caustic soda solution with respect to iron ions to prepare an aqueous solution containing ferrous hydroxide. Prepared. While maintaining the pH of the aqueous solution at 9, the air was blown in to carry out an oxidation reaction at 80 to 90 ° C. to prepare a slurry liquid for generating seed crystals.

[0232] Then, the slurry liquid contained 0.9-1..1 with respect to the initial amount of alkali (sodium component of caustic soda).
After adding ferrous sulfate aqueous solution to 2 equivalents, the pH of the slurry liquid was maintained at 8 and the oxidation reaction was promoted while blowing air, and the pH was adjusted to about 6 at the end of the oxidation reaction, and silane coupling was performed. agent _{[n-C 4 H 9 Si} (OCH 3) 3] was added 0.5 parts per 100 parts of iron oxide, were thoroughly stirred. The produced hydrophobic iron oxide particles were washed, filtered, and dried by a conventional method, and then the aggregated particles were crushed to obtain hydrophobic iron oxide 1. Table 2 shows the physical properties of the hydrophobic iron oxide 1.

Production Example 2 of Hydrophobic Iron Oxide The oxidation reaction was carried out in the same manner as in Production Example 1, and the iron oxide particles produced after the oxidation reaction were washed, filtered, taken out once, and dried again in another water without drying. after dispersing, and adjusting the pH of the redispersion liquid, with good stirring a silane coupling agent _{[n-C 6 H 13 Si} (OC
H ₃ ) ₃ ] was added in an amount of 0.5 part to perform a coupling treatment. The produced hydrophobic iron oxide particles were washed, filtered, and dried by a conventional method, and then the aggregated particles were lightly crushed to obtain hydrophobic iron oxide 2.

Production Example 3 of Hydrophobic Iron Oxide Hydrophobic iron oxide ₃ was produced in the same manner as in Production Example 2 except that nC ₁₀ H ₂₁ Si (OCH ₃ ) ₃ was used as the silane coupling agent.
Got

Production Example 4 of Hydrophobic Iron Oxide Hydrophobic iron oxide 4 was obtained in the same manner as in Production Example 2 except that γ-glycidyltrimethoxysilane was used as the silane coupling agent.

Production Example 5 of Hydrophobic Iron Oxide A ferrous sulfate aqueous solution is mixed with 1.0 to 1.1 equivalents of caustic soda solution with respect to iron ions to prepare an aqueous solution containing ferrous hydroxide. Prepared. While maintaining the pH of the aqueous solution at 9, the air was blown in to carry out an oxidation reaction at 80 to 90 ° C. to prepare a slurry liquid for generating seed crystals.

[0237] Next, the slurry liquid contained 0.9-1..1 to the initial amount of alkali (sodium component of caustic soda).
After adding a ferrous sulfate aqueous solution to 2 equivalents, the slurry liquid was maintained at pH 8 and the oxidation reaction was promoted while blowing air, and the pH was adjusted at the final stage of the oxidation reaction to complete the oxidation reaction. The produced particles are washed, filtered and dried by a conventional method, and then the aggregated particles are crushed to obtain iron oxide particles a.
Got The resulting iron oxide particles a 10-fold dilution with methanol at gas phase silane coupling agent [n-C ₆ H ₁₃
Hydrophobic iron oxide 5 was obtained by hydrophobizing with Si (OCH ₃ ) ₃ ] (adjusting the coupling agent to be 0.5 part with respect to 100 parts of iron oxide).

Production Example 6 of Hydrophobic Iron Oxide The iron oxide particles a obtained in Production Example 5 of hydrophobic iron oxide are dispersed in water,
By adjusting the pH of the iron oxide aqueous dispersion, a silane coupling agent _{[n-C 6 H 13 Si} (OCH 3) 3] 0.5 parts were added and was thoroughly mixed and stirred. The produced hydrophobic iron oxide particles were washed, filtered, and dried by a conventional method, and then the aggregated particles were crushed to obtain hydrophobic iron oxide 6.

Table 2 shows the physical properties of the above hydrophobic iron oxides 2 to 6.

[0240]

[Table 2]

<Manufacture of Toner Particles> (Manufacture Example 1 of Toner Particles) 709 parts of ion-exchanged water was mixed with 0.
After adding 451 parts of a 1 mol / liter-Na ₃ PO ₄ aqueous solution and heating to 60 ° C., 1.0 mol / liter-Ca
67.7 parts of Cl ₂ aqueous solution was gradually added to Ca ₃ (P
An aqueous medium containing O ₄ ) ₂ was obtained. On the other hand, the following formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Kakoki Co., Ltd.). -Styrene 80 parts-n-butyl acrylate 20 parts-Unsaturated polyester resin 2 parts (obtained by condensation reaction of propylene oxide adduct of bisphenol A and ethylene oxide adduct with fumaric acid) -Negatively charge control agent 4 parts (Monoazo dye-based Fe compound represented by the following general formula (III))-Hydrophobic iron oxide 1 100 parts

[0242]

[Chemical 3]

This monomer composition was heated to 60 ° C., 20 parts of ester wax having an endothermic peak temperature in DSC of 70 ° C. was mixed and dissolved therein, and the polymerization initiator 2, 2 ′ was added thereto.
-Azobis (2,4-dimethylvaleronitrile [t1 / 2
= 140 minutes, at 60 ° C.] 8 parts and dimethyl-2,
2'-azobisisobutyrate [t1 / 2 = 270 minutes, 60
C conditions; t1 / 2 = 80 minutes, 80C conditions] 2 parts were dissolved.

The above polymerizable monomer system was introduced into the above aqueous medium, and the mixture was subjected to 10,000 rpm at 60 ° C. in a N ₂ atmosphere using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).
Stir for 15 minutes and granulate. Then, the mixture was reacted with the paddle stirring blade at 60 ° C. for 1 hour while stirring. Then increase the liquid temperature to 8
The temperature was raised to 0 ° C. and stirring was continued for 10 hours. After the reaction was completed, the suspension was cooled and hydrochloric acid was added to dissolve Ca ₃ (PO ₄ ) ₂ .
Toner particles 1 were obtained by filtering, washing with water and drying.

(Production Example 2 of Toner Particles) In the same manner as Production Example 1 of toner particles, except that the hydrophobic iron oxide 1 was changed to 100 parts of the hydrophobic iron oxide 2 and the stirring speed during granulation was changed. Toner particles 2 are obtained.

(Production Example 3 of Toner Particles) Toner particles 3 were obtained in the same manner as in Production Example 1 of toner particles except that the hydrophobic iron oxide 1 was changed to 150 parts of the hydrophobic iron oxide 3.

(Production Example 4 of Toner Particles) Toner particles 4 were obtained in the same manner as in Production Example 1 of toner particles, except that the hydrophobic iron oxide 1 was changed to 190 parts of hydrophobic iron oxide 4.

(Production Examples 5 and 6 of Toner Particles) In Production Example 3 of toner particles, the amount of hydrophobic iron oxide 3 used was 4
Change to 0 part or 200 parts, Na ₃ PO ₄ aqueous solution and CaC
Toner particles 5 and 6 were obtained in the same manner as in Example 3 except that the amount of the l ₂ aqueous solution added was changed.

(Production Example 7 of toner particles) Ion-exchanged water 7
09 parts of 0.1 mol / liter -Na ₃ PO ₄ aqueous 4
After adding 51 parts and heating to 60 ° C., 67.7 parts of a 1.0 mol / liter-CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . On the other hand, the following formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Kakoki Co., Ltd.). -Styrene 82 parts-n-butyl acrylate 18 parts-Polyester resin 5 parts-Hydrophobic iron oxide 1 100 parts

This monomer composition was heated to 60 ° C., and 8 parts of a polymerization initiator 2,2′-azobis (2,4-dimethylvaleronitrile [t 1/2 = 140 minutes, 60 ° C.]] was added thereto. And dimethyl-2,2'-azobisisobutyrate [t1 / 2 =
270 minutes at 60 ° C .; t 1/2 = 80 minutes at 80 ° C.] 2 parts were dissolved.

The above polymerizable monomer system was introduced into the above aqueous medium, and the mixture was 10,000 rpm at 60 ° C. under N ₂ atmosphere using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.).
Stir for 15 minutes and granulate. Then, the mixture was reacted with the paddle stirring blade at 60 ° C. for 1 hour while stirring. Then increase the liquid temperature to 8
The temperature was raised to 0 ° C. and stirring was continued for 10 hours. After the reaction was completed, the suspension was cooled and hydrochloric acid was added to dissolve Ca ₃ (PO ₄ ) ₂ .
It was filtered, washed with water, and dried to obtain iron oxide-containing resin powder having a weight average particle diameter of 10.0 μm.

Then, 205 parts of the iron oxide-containing resin powder described above, 0.8 part of a negative charge control agent (monoazo dye-based Fe compound), and 3 parts of ethylene-propylene copolymer (Mw = 6000) were mixed. , Melt-kneading with a twin-screw extruder heated to 140 ° C., cooling the kneaded product, coarsely pulverizing with a hammer mill, finely pulverizing the coarsely pulverized product with a jet mill, and classifying the obtained finely pulverized product with wind. Toner particles 7 are obtained.

(Manufacturing Example 8 of Toner Particles) Toner particles 8 were obtained by subjecting toner particles 7 to a surface treatment by a mechanical impact force. (Production Example of Toner Particles 9) Toner particles 9 were obtained in the same manner as in Production Example 1 of toner particles except that the hydrophobic iron oxide 1 was replaced with 100 parts of the hydrophobic iron oxide 5.

(Production Example of Toner Particles 10) Toner particles 10 were obtained in the same manner as in Production Example 1 of toner particles except that the hydrophobic iron oxide 1 was changed to 150 parts of the hydrophobic iron oxide 6.

(Production Example of Toner Particles 11) By the same method as in Production Example 1 of toner particles except that the wax used is 10 parts of ester wax having an endothermic peak temperature in DSC of 75 ° C., a weight average particle diameter is obtained. 7.0 μm
Toner particles 11 of are obtained.

(Production Example of Toner Particles 12) In Production Example 11 of toner particles, the amount of ester wax used is 51
The weight average particle diameter of 8.2
Toner particles 12 having a size of μm were obtained.

(Production Example of Toner Particles 13) In Production Example 11 of toner particles, the amount of the ester wax used is 0.
A weight average particle size of 6.
8 μm toner particles 13 were obtained.

(Production Example of Toner Particles 14) In Production Example 11 of toner particles, DSC is used instead of the ester wax.
By the same method except that 10 parts of low molecular weight polyethylene wax having an endothermic peak temperature of 115 ° C. in
Toner particles 14 having a weight average particle diameter of 8.4 μm were obtained.

<Production of Toner> (Toner Production Examples 1 to 15) Using Toner Particles 1, 100 parts of toner particles, fine particles and silica fine particles are as shown in Table 3, and a Henschel mixer (Mitsui Miike Kako Co., Ltd.) is used. Inkki Co., Ltd., to prepare toners 1 to 15 by appropriately adjusting the mixing conditions. Table 4 shows the physical properties of Toners 1 to 15.

[0260]

[Table 3]

[0261]

[Table 4]

The state of dispersion of the hydrophobic iron oxide inside the toner particles of Toner 1 was evaluated by observing the tomographic plane of the toner particles using a transmission electron microscope (TEM). As a specific evaluation method by TEM, the same method as in the case of determining the volume average particle size and particle size distribution of iron oxide in the toner particles described above was used.

The specific evaluation of the dispersed state of the hydrophobic iron oxide inside the toner particles was carried out as follows. A particle fault plane having a diameter of ± 10% of the number average particle diameter of the toner is extracted, and a similar figure with a diameter of half is drawn with the same center as the fault plane (the area of the similar figure is 1 of the particle fault plane area). / 4).

Next, within the particle fault plane (including within a similar figure)
The number of the hydrophobic iron oxide powder having a particle size of 0.03 μm or more existing in is counted, and the number is defined as a. Similarly, the number of 0.03 μm or more hydrophobic iron oxide powders present in the similar figure is counted, and the number is designated as b. The ratio b / a of a and b thus obtained is calculated. As the value of the ratio b / a is closer to 1/4 which is the area ratio of each surface, the hydrophobic iron oxide powder has the same abundance from the center of the toner particle to the vicinity of the surface layer, that is, in the toner particle. Means that the dispersed state of the hydrophobic iron oxide is uniform, and the value of b / a is 3/8 to 1
In the range of / 5, it can be said that almost good dispersion is achieved.

When b / a of Toner 1 was determined,
It was about 1/4, and it was found that the dispersed state of the hydrophobic iron oxide in the toner particles was very uniform.

(Toner Production Examples 16 to 28) Toner particles 2 to 14 were used, and 100 parts of the toner particles, fine particles and silica fine particles were each provided in a Henschel mixer (Mitsui Miike Kakoki ( Co., Ltd.) to prepare toners 16 to 28 by appropriately adjusting the mixing conditions. Table 6 shows the physical properties of Toners 16 to 28.

[0267]

[Table 5]

[0268]

[Table 6]

With respect to Toner 23, the dispersion state of iron oxide inside the particles was evaluated by TEM observation in the same manner as in Toner 1. As a result, b / a was about ⅛, and iron oxide inside the toner particles was found to be about 1/8. It was found that the dispersed state was non-uniform, and a large amount was present especially on the surface of the toner particles. This is considered to be because the hydrophobicity of iron oxide was non-uniform, and thus a large amount of iron oxide powder having low hydrophobicity was collected on the surface of toner particles during suspension polymerization.

Further, with respect to the toner 24, when the dispersion state of the iron oxide inside the particles was evaluated by TEM observation as in the case of the toner 1, b / a was about 1/6, and the oxidation inside the toner particles was found. It was found that the dispersed state of iron was non-uniform, and the amount of iron was particularly large on the surface of the toner particles.

[0271]

Examples 1 to 12 and Comparative Examples 1 to 3 Toners 1 to 15 were used to form an image pattern consisting of only vertical lines with a printing area ratio of 2% under a normal temperature and normal humidity environment (23 ° C., 60% RH). Then, an image output test of 8,000 sheets was performed.

The image forming apparatus used in Examples 1 to 12 and Comparative Examples 1 to 3 will be described. A 600 dpi laser beam printer (LBP-860 manufactured by Canon Inc.) was prepared as an image forming apparatus having the configuration shown in FIG. The process speed was modified to 60 mm / s.

The cleaning blade in the process cartridge was removed, and the charging system of the apparatus was direct charging by contacting with a rubber roller, and the applied voltage was only the DC component (-1200V).

Next, the developing portion of the process cartridge was modified. Instead of the stainless steel sleeve which is the toner carrier, a medium resistance rubber roller (diameter 16 mm, hardness A made of silicone rubber in which carbon black is dispersed)
SKER C 45 degrees, resistance 10 ⁵ Ω · cm)
It was brought into contact with the photoconductor. The developing contact width at this time was set to about 3 mm. The rotational peripheral speed of the toner carrier is in the same direction at the contact portion with the photoconductor, and the toner is driven to be 140% of the rotational peripheral speed of the photoconductor.

The photoreceptor used here is an Al cylinder having a diameter of 30 mm and a length of 254 mm shown in FIG. 4 as a substrate, on which layers having the following constitution are sequentially laminated by dip coating. , A photoconductor was prepared. (1) Conductive coating layer: Mainly composed of a powder of tin oxide and titanium oxide dispersed in a phenol resin. Film thickness 15μ
m. (2) Undercoat layer: Mainly composed of modified nylon and copolymer nylon. The film thickness is 0.6 μm. (3) Charge generation layer: Mainly composed of a butyral resin in which a titanyl phthalocyanine pigment having absorption in a long wavelength region is dispersed. The film thickness is 0.6 μm. (4) Charge transport layer: Mainly composed of a hole-transporting triphenylamine compound dissolved in a polycarbonate resin (molecular weight of 20,000 by Ostwald viscosity method) at a mass ratio of 8:10. Film thickness 20 μm.

As a means for applying toner to the toner carrier, a developing roller made of urethane foam rubber was provided inside the developing device and brought into contact with the toner carrier. A voltage of about -550V is applied to the coating roller. Further, in order to control the coating layer of the toner on the toner carrier, a resin-coated stainless steel blade was attached as a layer thickness regulating member so that the contact pressure with the toner carrier was about 20 g / cm. The applied voltage during development is the DC component (-450
V) only.

The image forming apparatus was modified and the process conditions were set as follows so as to be compatible with the modification of these process cartridges.

The modified device uses a roller charging device (applying only direct current) to uniformly charge the photoconductor. After charging, an electrostatic latent image is formed by exposing the image portion with a laser beam, and a visible image is formed by developing with a toner, and then the toner image is transferred onto a transfer material by a roller to which a voltage of +700 V is applied. To have.

The photoconductor charging potential is -6 in the dark area potential.
It was set to 30V, and the light portion potential was set to -150V. 75 g / m ² of paper was used as the transfer material.

Table 7 shows the evaluation results of the fog amount, the image density, the transfer efficiency, and the contamination property of the charging member. The evaluation method is as follows. a) The image density was measured with a Macbeth densitometer RD918 (manufactured by Macbeth). b) Fog is measured by REFLECT METER MOD manufactured by Tokyo Denshoku Co., Ltd.
Measured using ELTC-6DS. A green filter was used as the filter, and it was calculated from the following formula.

[0281]

## EQU00003 ## Fog (reflectance) (%) = reflectance (%) on standard paper-reflectance (%) of non-image portion of sample If the fog is 2.0% or less, a good image is obtained. c) The transfer efficiency is such that the transfer residual toner on the photoconductor after the transfer of the solid black image is taped off with Mylar tape, and is peeled off, and the value of the Macbeth density of the product is C on the paper, and after the transfer, on the paper on which the toner is not fixed. When the Macbeth density of the product with Mylar tape attached was E and the Macbeth density of the Mylar tape with unused paper was D, it was approximately calculated by the following formula. If the transfer efficiency is 90% or more, the image has no problem.

[0282]

[Equation 4]

D) The contamination of the charging member by the toner is 6
Evaluation was made on the uneven charging due to contamination of the charging member on the solid white image at the time of printing 000 sheets. A: No charging unevenness was generated B: Minor charging unevenness was generated at the end C: Minor charging unevenness was generated on the whole D: Charging unevenness was generated on the whole In the same manner, in a high temperature and high humidity environment (32.5 ° C., 90%) R
H) and a low temperature and low humidity environment (10 ° C., 10% RH). The results are shown in Table 7.

[0284]

[Table 7]

After the end of the durability test at room temperature and normal humidity, a solid black image was printed, and the number of white spots due to the toner fusion on the drum was counted to evaluate the drum fusion. Examples 1 to 12
In all cases, a good solid black image was obtained and the evaluation was A, but in Comparative Examples 1 to 3, white spots occurred, and the evaluation was C in all cases.

Here, the evaluation criteria for drum fusion are as follows. A: 2 or less white spots on solid black paper B: 3 to 5 white spots on solid black paper C: 6 to 8 white spots on solid black paper D: White spot on solid black paper , 9 or more Comparative Examples 1 and 3, the tin oxide fine particles 6 and 8 used,
Since they were black blue and black, respectively, dot-like image stains due to scattering of tin oxide fine particles on the white background were conspicuous, and the images were not practical.

[0287]

[Examples 13 to 24 and Comparative Examples 4 to 6] Toners 1 to 15
And a commercially available laser beam printer LBP-SX (manufactured by Canon Inc.) for developing by a non-contact developing method was modified as shown below using an image forming apparatus as shown in FIG. The image forming test was performed on 8,000 sheets at an image pattern consisting of only vertical lines having a printing area ratio of 2% at 60 ° C and 60% RH.

The toner layer thickness regulating member in the process cartridge portion is changed to an elastic blade made of urethane rubber, a toner applying roller and a cleaning magnet roller are installed, and the magnet contained in the toner carrier (developing sleeve) 15 is removed. I remodeled it.

Image forming conditions are shown below.

FIG. 7 illustrates the alternating voltage used. Vdc represents a DC power supply voltage, Vd represents a dark portion potential on the image carrier, and VL represents a light portion potential. f is the frequency of the alternating voltage, and Vpp is the peak-to-peak voltage of the alternating voltage. An electrostatic latent image was formed with Vd of −670 V, and a gap (300 μm) was set so that the photoconductor 100 and the toner layer on the toner carrier 102 were not in contact with each other. Toner carrier 102
AC bias (f = 32
00Hz Vpp = 1800V and DC bias (V
dc = -400V) was applied, VL was set to -150V, and image formation was performed.

The peripheral speed ratio of the toner carrier to the photoconductor is set to 2
It was set to 00%.

Table 8 shows the evaluation results of the amount of fog, the image density, the transfer efficiency, and the stain resistance of the charging member. The evaluation method is as follows.

A) image density, b) fog, and c) transfer efficiency were the same as in Example 1. d) The dot reproducibility was evaluated by performing an image drawing test using a checker pattern of 80 μm × 50 μm shown in FIG. 8 and observing the presence or absence of a black portion defect with a microscope. A: 2 or less defects in 100 B: 3-5 defects in 100 C: 6-10 defects in 100 D: 11 or more defects in 100 Similarly, high temperature and high humidity environment Lower (32.5 ° C, 90% R
H) and a low temperature and low humidity environment (10 ° C., 10% RH). The results are shown in Table 8.

[0294]

[Table 8]

After the end of the durability test at room temperature and normal humidity, a solid black image was printed, and the number of white spots due to the toner fusion on the drum was counted to evaluate the drum fusion. Examples 13 to 2
In No. 4, a good solid black image was obtained and the evaluation was A, but in Comparative Examples 4 to 6, white spots occurred, and the evaluation was C in all cases. Here, the evaluation criteria for drum fusion were as follows. A: 2 or less white spots on solid black paper B: 3 to 5 white spots on solid black paper C: 6 to 8 white spots on solid black paper D: White spot on solid black paper , 9 or more Comparative Examples 4 and 6, the tin oxide fine particles 6 and 8 used,
Since they were black blue and black, respectively, dot-like image stains due to scattering of tin oxide fine particles on the white background were conspicuous, and the images were not practical.

[0296]

Examples 25 to 36 and Comparative Example 7 Using toners 9 to 28, the same image forming test as in Example 1 was conducted. Table 8 shows the evaluation results of the fog amount, the image density, the transfer efficiency, and the contamination property of the charging member. Similarly, in a high temperature and high humidity environment (32.5 ° C., 90% RH) and a low temperature and low humidity environment (10
The imaging test was performed at 10 ° C and 10% RH. The results are shown in Table 9.

[0297]

[Table 9]

[0298]

Examples 37 to 48 and Comparative Example 8 Using toners 16 to 28, the same image forming test as in Example 13 was conducted. Table 10 shows the evaluation results of the fog amount, image density, dot reproducibility, and transfer efficiency. Similarly, in a high temperature and high humidity environment (32.5 ° C., 90% RH) and a low temperature and low humidity environment (10
The imaging test was performed at 10 ° C and 10% RH. The results are shown in Table 10.

[0299]

[Table 10]

[0300]

EFFECTS OF THE INVENTION According to the present invention, it is not easily influenced by the environment, has stable charging performance, suppresses the generation of fog even after long-term use, does not lower the image density, and has high transferability. It is possible to provide a toner having In addition, there is little transfer residual toner, toner fusion on the surface of the photoreceptor and contamination of the charging member due to transfer residual toner are suppressed, and images with high quality and excellent resolution with no image defects even during long-term use. It is possible to provide an image forming method and an image forming apparatus capable of stably obtaining the image for a long time.

[Brief description of drawings]

FIG. 1 illustrates an example of an image forming apparatus of the present invention.

FIG. 2 is an enlarged view of a developing device portion of the image forming apparatus shown in FIG.

FIG. 3 is a diagram showing an example of a contact transfer member used in the image forming apparatus of the present invention.

FIG. 4 is a diagram showing an example of a configuration of a photoconductor used in the image forming apparatus of the present invention.

FIG. 5 is a diagram showing an example of an image forming apparatus of the present invention.

6 is an enlarged view of a developing device portion of the image forming apparatus shown in FIG.

FIG. 7 is a diagram showing a pattern of a developing bias used in the image forming method of the present invention.

FIG. 8 is an explanatory diagram of a checkered pattern for testing a developing property of toner in an example.

[Explanation of symbols]

1 photoconductor 4 Toner carrier 14 Transfer member 17 Charging member 34 transfer roller 40 Developing device 100 photoconductor 102 toner carrier 114 transfer member 116 Cleaning means 117 charging member 140 developing device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/08 501 501 G03G 9/08 301 507 384 15/16 103 15/08 507B 507L (72) Inventor Mizoe Nozomi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Fumihiro Arahira 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H005 AA02 AA03 AA06 AA08 AB02 AB06 CA14 CB03 CB07 DA07 EA01 EA03 EA05 EA07 FA06 FB02 FC03 2H077 AA37 AC11 AC16 AD02 AD06 BA03 EA15 FA01 FA21 GA02 2H200 FA01 GA23 GA31 GA44 GA52 GB11 GB21 GB37 HA02 HA28 HB12 HB48 NA06

Claims (74)

[Claims] 1. A toner containing at least a binder resin and a colorant, the toner having toner particles and fine particles, and having an average circularity of 0.950 to 0.995, wherein the fine particles are tungsten. It is a tin oxide fine particle containing an element and has a molar ratio (Sn / W) of tungsten element (W) to tin element (Sn) of 0.001 or more and 0.3.
A toner having the following characteristics. 2. The fine particles are present at least on the surface of the toner particles, and the fine particles present on the surface of the toner particles are present in a ratio of 0.3 or more per toner. The toner according to claim 1. 3. The fine particles have a volume average particle size of 0.1 μm.
The toner according to claim 1 or 2, wherein the toner has a size of m or more and less than 5 μm. 4. The ratio (S / T) of the average particle size S of the fine particles to the average particle size T of the toner is 0.5 or less, according to claim 1. toner. 5. The particles have a resistance of 1 × 10 ⁹ Ωcm.
The toner according to any one of claims 1 to 4, wherein: 6. The toner according to claim 1, wherein a standard deviation of circularity distribution of the toner is 0.040 or less. 7. The toner comprises magnetic powder mainly composed of magnetite as the coloring agent, and the magnetic powder is not substantially exposed on the surface of the toner. 7. The toner according to any one of 1 to 6. 8. The toner has a ratio (B / A) of the iron element content (B) to the carbon element content (A) present on the toner surface measured by X-ray photoelectron spectroscopy (B / A) of not more than 0. The toner according to claim 7, which is less than 001. 9. When the particle diameter of the toner is C and the minimum value of the distance between the magnetic powder and the surface of the toner particle is D in observation of the tomographic plane of the toner using a transmission electron microscope (TEM). , D / C ≦ 0.02 toner is 5
9. The toner according to claim 7, wherein the toner content is 0% by number or more. 10. The toner according to claim 9, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 65% by number or more. 11. The toner according to claim 9, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 75% by number or more. 12. The toner according to claim 7, wherein the magnetic powder is contained in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. 13. The toner according to claim 7, wherein the magnetic powder is contained in an amount of 20 to 180 parts by mass with respect to 100 parts by mass of the binder resin. 14. The toner according to claim 1, wherein a part or the whole of the toner particles in the toner is obtained by a polymerization method. 15. The toner according to claim 7, wherein the magnetic powder is surface-treated while hydrolyzing a coupling agent in an aqueous medium. 16. The toner according to claim 1, wherein the toner contains wax in an amount of 0.5 to 50 mass% with respect to the entire toner. 17. The toner according to claim 1, wherein the wax has an endothermic peak by differential thermal analysis of 40 to 110 ° C. 18. The toner according to claim 1, wherein the wax has an endothermic peak by differential thermal analysis of 45 to 90 ° C. 19. A charging step of applying a voltage to a charging member to charge an image carrier, an exposing step of forming an electrostatic latent image on the image carrier charged by exposure, and a toner step on a toner carrier. A developing step of transferring the carried toner to the electrostatic latent image held on the surface of the image carrier to form a toner image, and electrostatically transferring the toner image formed on the image carrier to a transfer material. In the image forming method including at least a transfer step of transferring, the toner has toner particles and fine particles containing at least a binder resin and a colorant, and has an average circularity of 0.95.
0 to 0.995, the fine particles are tin oxide fine particles containing a tungsten element, and the molar ratio (Sn / W) of the tungsten element (W) to the tin element (Sn) is 0.001 or more and 0.3 or more.
An image forming method comprising the following fine particles. 20. The contact developing step, wherein the developing step is a contact developing step in which the electrostatic latent image on the image carrier and the toner carried on the toner carrier are brought into contact with each other. The image forming method described. 21. The image forming method according to claim 19, wherein the toner carrier is an elastic roller. 22. In the developing step, the moving speed of the surface of the toner carrier in the developing area is 1.05 to 3.0 times the moving speed of the surface of the image carrier. The image forming method according to any one of 19 to 21. 23. The toner carrier has a surface roughness Ra of 0.2 to 3.0 μm.
23. The image forming method according to any one of 22 to 22. 24. The image forming method according to claim 19, wherein in the developing step, the transfer residual toner remaining on the image carrier after the transfer step is collected by the toner carrier. Method. 25. The image forming method according to claim 19, wherein the charging step is a contact charging step in which a charging member is brought into contact with an image carrier to perform charging. 26. The transfer step is a contact transfer step in which a toner image is transferred to a transfer material by a transfer member that contacts the image carrier via the transfer material.
The image forming method according to any one of 9 to 25. 27. The image forming method according to claim 19, further comprising a fixing step of fixing the toner image transferred on the transfer material to the transfer material. 28. The image forming method according to claim 19, wherein the fine particles are present at least on the surface of the toner. 29. The image forming method according to claim 19, wherein the fine particles existing on the surface of the toner are present in a ratio of 0.3 or more per one toner. . 30. The fine particles have a volume average particle diameter of 0.1.
20. It is more than [mu] m and less than 5 [mu] m.
30. The image forming method according to any one of 29 to 29. 31. The ratio (S / T) of the average particle diameter S of the fine particles to the average particle diameter T of the toner is 0.5 or less, according to claim 19. Image forming method. 32. The fine particles have a resistance of 1 × 10 ⁹ Ωc.
32. The image forming method according to claim 19, wherein the image forming method is m or less. 33. The toner according to claim 19, wherein a standard deviation of circularity distribution is 0.040 or less.
32. The image forming method according to any one of 32. 34. The toner comprises magnetic powder mainly composed of magnetite as the coloring agent, and the magnetic powder is not substantially exposed on the surface of the toner. The image forming method according to any one of 19 to 33. 35. The toner has a ratio (B / A) of the iron element content (B) to the carbon element content (A) present on the toner surface measured by X-ray photoelectron spectroscopy of 0. The image forming method according to claim 34, which is less than 001. 36. When the particle diameter of the toner is C, and the minimum value of the distance between the magnetic powder and the surface of the toner particle is D in observation of the tomographic plane of the toner using a transmission electron microscope (TEM).
36. The image forming method according to claim 34 or 35, wherein 50% by number or more of the toners satisfy the relationship of D / C ≦ 0.02. 37. The image forming method according to claim 36, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 65% by number or more. 38. The image forming method according to claim 36, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 75% by number or more. 39. The image forming method according to claim 34, wherein the magnetic powder is contained in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. 40. The image forming method according to claim 34, wherein the magnetic powder is contained in an amount of 20 to 180 parts by mass with respect to 100 parts by mass of the binder resin. 41. The image forming method according to claim 19, wherein a part or the whole of the toner particles in the toner is obtained by a polymerization method. 42. The image forming method according to claim 34, wherein the magnetic powder is surface-treated while hydrolyzing the coupling agent in an aqueous medium. 43. The image forming method according to claim 19, wherein the toner contains wax in an amount of 0.5 to 50 mass% with respect to the entire toner. 44. The image forming method according to claim 19, wherein the wax has an endothermic peak by differential thermal analysis of 40 to 110 ° C. 45. The image forming method according to claim 19, wherein the wax has an endothermic peak by differential thermal analysis of 45 to 90 ° C. 46. The toner has an average circularity of 0.97.
It is 0-0.995, It is characterized by the above-mentioned 19-4.
6. The image forming method according to any one of 5 above. 47. An image carrier, a charging unit for applying a voltage to a charging member to charge the image carrier, and an exposing unit for forming an electrostatic latent image on the image carrier charged by exposure. Developing means for transferring the toner carried on the toner carrier to the electrostatic latent image carried on the surface of the image carrier to form a toner image; and a toner image formed on the image carrier. In the image forming apparatus, the toner has at least a binder resin and a colorant containing at least a binder, and an average circularity of 0.95.
0 to 0.995, the fine particles are tin oxide fine particles containing a tungsten element, and the molar ratio (Sn / W) of the tungsten element (W) to the tin element (Sn) is 0.001 or more and 0.3 or more.
An image forming apparatus comprising the following fine particles. 48. The developing device is a contact developing device for performing development while bringing the electrostatic latent image on the image carrier into contact with the toner carried on the toner carrier. The image forming apparatus described. 49. The image forming apparatus according to claim 47, wherein the toner carrier is an elastic roller. 50. In the developing means, the moving speed of the surface of the toner carrier in the developing area is 1.05 to 3.0 times the moving speed of the surface of the image carrier. The image forming apparatus according to any one of 47 to 49. 51. The toner carrier has a surface roughness Ra of 0.2 to 3.0 μm.
The image forming apparatus according to any one of 1 to 50. 52. The developing device is a device for collecting the transfer residual toner remaining on the image bearing member after the transfer by the toner bearing member. Image forming apparatus. 53. The image forming apparatus according to claim 47, wherein the charging unit is a contact charging unit that charges the image bearing member by bringing the charging member into contact with the image bearing member. 54. The transfer means is a contact transfer means for transferring a toner image onto a transfer material by means of a transfer member which is in contact with the image carrier via the transfer material.
The image forming apparatus according to any one of 7 to 53. 55. The image forming apparatus according to claim 47, further comprising fixing means for fixing the toner image transferred on the transfer material to the transfer material. 56. The image forming apparatus according to claim 47, wherein the fine particles are present at least on the surface of the toner. 57. The image forming apparatus according to claim 47, wherein the fine particles existing on the surface of the toner are present in a ratio of 0.3 or more per one toner. . 58. The fine particles have a volume average particle diameter of 0.1.
48. The thickness is not less than μm and less than 5 μm.
The image forming apparatus according to any one of to 57. 59. The ratio (S / T) of the average particle size S of the fine particles to the average particle size T of the toner is 0.5 or less. Image forming apparatus. 60. The fine particles have a resistance of 1 × 10 ⁹ Ωc.
The image forming apparatus according to any one of claims 47 to 59, wherein the image forming apparatus has a thickness of m or less. 61. The toner according to claim 47, wherein the standard deviation of the circularity distribution is 0.040 or less.
60. The image forming apparatus according to any one of 60. 62. The toner comprises magnetic powder mainly composed of magnetite as the coloring agent, and the magnetic powder is not substantially exposed on the surface of the toner. The image forming apparatus according to any one of 47 to 61. 63. The toner has a ratio (B / A) of the iron element content (B) to the carbon element content (A) present on the toner surface measured by X-ray photoelectron spectroscopy of 0.1. 63. The image forming apparatus according to claim 62, which is less than 001. 64. When the particle diameter of the toner is C, and the minimum value of the distance between the magnetic powder and the toner particle surface is D in observation of the tomographic plane of the toner using a transmission electron microscope (TEM).
64. The image forming apparatus according to claim 62 or 63, wherein 50% by number or more of the toners satisfy the relationship of D / C ≦ 0.02. 65. The image forming apparatus according to claim 64, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 65% by number or more. 66. The image forming apparatus according to claim 64, wherein the toner satisfying the relationship of D / C ≦ 0.02 is 75% by number or more. 67. The image forming apparatus according to claim 62, wherein the magnetic powder is contained in an amount of 10 to 200 parts by mass with respect to 100 parts by mass of the binder resin. 68. The image forming apparatus according to claim 62, wherein the magnetic powder is contained in an amount of 20 to 180 parts by mass with respect to 100 parts by mass of the binder resin. 69. The image forming apparatus according to claim 47, wherein the toner particles in the toner are partially or wholly obtained by a polymerization method. 70. The image forming apparatus according to claim 62, wherein the magnetic powder is surface-treated while hydrolyzing the coupling agent in an aqueous medium. 71. The image forming apparatus according to claim 47, wherein the toner contains wax in an amount of 0.5 to 50 mass% with respect to the entire toner. 72. The image forming apparatus according to claim 47, wherein the wax has an endothermic peak by differential thermal analysis of 40 to 110 ° C. 73. The image forming apparatus according to claim 47, wherein the wax has an endothermic peak by differential thermal analysis of 45 to 90 ° C. 74. The toner has an average circularity of 0.97.
It is 0-0.995, 47 to 7 characterized by the above-mentioned.
The image forming apparatus according to any one of 3 above.