JP2003149871A - Toner for image formation and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide non-magnetic one-component toner by which a good gradation curve can be continuously obtained and good image gradation and image density can be obtained even under the condition of high humidity and an image forming method by a one-component system contact developing method using the toner. SOLUTION: In the method, image formation is carried out by using non- magnetic one-component toner containing pigment provided with a special construction and a toner image is developed by using a developing device in which NE length is >=0.1 mm and <5.0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic latent image used in an electrostatic copying machine, a laser printer or the like, and to an image forming method using the toner. .

[0002]

2. Description of the Related Art In recent years, with the spread of copying machines and printers using electrophotography, further speeding up, downsizing, full color, and high image quality of these machines are required.

Further, as the number of users increases, cost reduction and free maintenance of copying machines and printers are required, and as a result, it is also necessary to reduce the number of parts and simplify the machine structure of the machine body.

As a result, the technical requirements for consumer members such as toner and drums are increasing year by year.

As a developing method that achieves these requirements,
A contact developing method using a non-magnetic one-component developer (non-magnetic one-component contact developing method) is known.

The non-magnetic one-component developer has a toner main body which is excellent in low-temperature fixability as compared with a magnetic toner. Further, since it does not contain an opaque magnetic material, it is also a preferable developer for obtaining a full-color or multi-color image. Furthermore, since the consumed developer and the developing device have a simple structure, it is easy to reduce the size of the machine and achieve free maintenance.

In the contact developing method, the toner layer carried on the surface of the toner carrying member is brought into contact with the surface of the electrostatic latent image carrying member to develop the electrostatic latent image, thereby developing the toner image into the electrostatic latent image. This is a developing method in which it is formed on a carrier. Compared to the non-contact development method in which the toner layer carried on the surface of the toner carrier does not contact the surface of the electrostatic latent image carrier, fine line (or dot) reproducibility is excellent, and toner scattering is strong. There are merits. As described above, the non-magnetic one-component contact developing method is a very preferable developing method in order to achieve various requirements such as downsizing of machines, free maintenance, high definition of images, and full color.

However, as a result of various investigations by the present inventors, it became clear that the contact developing method has a problem in image quality as compared with the non-contact developing method. Further, as a result of further detailed examination, it has been clarified that the difference in image quality is caused by the gradation curve.

Here, the gradation curve is a graph in which the horizontal axis represents the number of gradations and the vertical axis represents the image density, and the relationship between the two is shown on one plane. FIG. 1 shows an example of the gradation curve. This figure is 64
The relationship between the gradation and the image density is shown, and the image sample that is output at 1200 dpi by the dither method (fattening) is used.

In general, it is necessary to clearly reproduce a high density portion in order to preferably reproduce a document mainly composed of character images, whereas a document mainly composed of photographic images or a mixture of photographic images and character images is used. In order to preferably reproduce an existing document, it is essential to reproduce stable densities in the intermediate density area and the low density area. In particular, the sensitivity of the human eye is more sensitive to the middle density part and below (density, about 1.2 or less) than high density, and the lower the density is, the more noticeable it is, so stable reproduction of the density below the middle density part is possible. As for the property, it is required that the density is higher than that of the conventional high-density area, and in particular, the extremely highlighted area (image area ratio of about 15% or less), which has hardly been a problem in the past.
The stable reproducibility of C has become a particularly important item for recent image forming apparatuses.

In order to correct the gradation of the image, software processing is usually performed. For example, JP-A-63-
In JP-A-208368, a large number of gradation pattern densities from a white level to a black level copied on a sheet are detected by a light receiving element, signal levels at which the densities are equidistant are obtained to obtain a gamma correction characteristic curve. A technique for gamma correction of the entire image forming apparatus using a memory that stores characteristic correction values is disclosed. As a method of setting the white level portion on the highlight side, the pulse widths of the white level and the black level are set (JP-A-62-181575), the bias of the reference pattern and the black level. ,
And the amount of light of the white level (Japanese Patent Laid-Open No. 63-17
No. 7153) is disclosed.

However, as is generally known, the photosensitivity of the photoconductor varies depending on the time of use and the environment of use, so the potential on the photoconductor changes, and even if the above setting is made, The concentration reproducibility of is not stable.

Further, even if the adjustment is made so that a stable image can be obtained regardless of the fluctuation of the photoconductor potential (JP-A-62-2).
No. 84578), in electrophotographic development, reproducibility of extremely extreme highlights varies due to mechanical dimensional error of the developing device, etc., and thus stable extremely high reproducibility cannot be obtained. .

These phenomena are more remarkable under high humidity conditions.

In the case of using the toner and the developing device configuration in which the gradient of the gradation curve is steep or the behavior of the gradation curve greatly varies depending on the use environment even if the software processing is performed as described above. However, it has been clarified by the inventors of the present invention that a preferable image gradation cannot be continuously obtained.

The present inventors have paid attention to this point and arrived at the present invention.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to obtain a preferable gradation curve, and to obtain a good image gradation and image density even under high humidity conditions. To provide a toner that is an agent.

Another object of the present invention is to provide an image forming method by a one-component system contact developing method which continuously gives good image gradation and image density even under high humidity conditions.

[0019]

The first aspect of the present invention is to apply a voltage to a charging member from the outside to charge the electrostatic latent image carrier, and to charge the electrostatic latent image carrier charged. A latent image forming step of forming an electrostatic latent image; a toner regulating member fixed so as to abut on a surface of a toner bearing body carrying toner, from the free end portion of the toner regulating member to the surface of the toner bearing body. The maximum length (NE length) to the contact part with is 0.1 mm
A toner layer forming step of regulating the toner layer on the toner carrier by bringing the toner regulating member into contact with the surface of the toner carrier so as to be less than 5.0 mm; carried on the surface of the toner carrier A developing step of developing the electrostatic latent image to form a toner image on the electrostatic latent image bearing member by bringing the toner layer into contact with the surface of the electrostatic latent image bearing member; A toner used in an image forming method having at least a transfer step of transferring to a transfer material without intervention; a fixing step of fixing a toner image on the transfer material;
The toner is a non-magnetic one-component toner having toner particles containing at least a binder resin and a colorant, and the colorant contains at least a pigment having a basic structural formula (1) shown below. And an image forming toner.

[0020]

[Chemical 3]

A second aspect of the present invention is a charging step of externally applying a voltage to a charging member to charge the electrostatic latent image carrier; an electrostatic latent image is charged on the charged electrostatic latent image carrier. Latent image forming step of forming; toner layer forming step in which the toner layer on the toner carrier is regulated by the toner regulating member; toner layer carried on the surface of the toner carrier is brought into contact with the surface of the electrostatic latent image carrier By doing so, a developing step of developing the electrostatic latent image to form a toner image on the electrostatic latent image carrier; a transfer step of transferring the toner image onto a transfer material with or without an intermediate transfer body; An image forming method including at least a fixing step of fixing a toner image on a transfer material, wherein a maximum length (NE length) from a free end portion of a toner regulating member to a contact portion with a surface of a toner carrier is 0. 1 mm or more and less than 5.0 mm, and the toner is A non-magnetic one-component toner having toner particles containing at least a binder resin and a colorant, wherein the colorant contains at least a pigment classified in the above basic structural formula (1). The present invention relates to an image forming method.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a result of intensive studies, the present inventors have used a non-magnetic one-component toner containing a specific pigment as a contact one-component developer, and have a NE length in the toner layer forming step. By defining the range, it was found that a preferable gradation curve can be continuously obtained under a high humidity condition, and an image having good image gradation can be continuously obtained, and the present invention has been completed.

The present invention is characterized in that the NE length range is 0.1 mm or more and less than 5.0 mm.

The present invention is also characterized by containing a pigment having the following basic structural formula (1).

[0025]

[Chemical 4]

In the present invention, the NE length refers to the length of the site shown in FIG.

That is, in FIG. 2, 5 is a toner container for containing the non-magnetic toner 4 as a one-component developer,
A developing sleeve 2 as a toner carrier, which is arranged to face the photosensitive drum 1 as an electrostatic latent image carrier, is rotatably arranged in an opening extending in the longitudinal direction in the toner container 5. . Further, the developing sleeve 2 is provided with the toner container 5
The right half peripheral surface shown in the figure protrudes into the toner container 5 and the left half peripheral surface is exposed outside the toner container 5 and is horizontally provided. The surface of the developing sleeve 2 exposed to the outside of the toner container 5 is in contact with the photosensitive drum 1 located to the left of the developing device 7 with a certain contact width.

An elastic regulating blade 3 is provided above the developing sleeve 2 as a toner regulating member so as to be supported by a pressing metal plate 6. The vicinity of the free end side of the elastic regulating blade 3 is the developing sleeve. The outer peripheral surface of 2 is abutted in a surface contact state. The contact direction of the elastic restriction blade 3 with respect to the developing sleeve 2 is a so-called counter (reverse) direction in which the tip end side is located on the upstream side in the rotation direction of the developing sleeve 2 with respect to the contact portion.

In FIG. 2, the point where the developing sleeve 2 and the elasticity regulating blade 3 contact outside the toner container 5 is designated as a. At this time, the length 8 from a to the tip of the free end of the elastic restriction blade 3 is the NE length.

As a result of earnest studies by the present inventors, NE
When the range of the length 8 is 0.1 mm or more and less than 5.0 mm, and the toner contains the pigment having the basic structural formula (1), a high gradation image continues even under high humidity conditions. Clarified that it can be obtained. The detailed reason for this is unknown, but it is presumed as follows.

That is, in the vicinity of the nip portion between the developing sleeve 2 and the elasticity regulating blade 3, the toner is rubbed with each other more actively than other portions, so that the toner 4 in this vicinity is uniformly pre-prepared. It is charged. Due to this pre-charging, the toner particles can have a more uniform charge after rubbing against the elasticity regulating blade 3.

When the NE length 8 is less than 0.1 mm, the amount of pre-charged toner is very small, so that the charge amount of the toner particles after passing through the nip portion varies. Toner particles having a non-uniform charge amount are extremely disadvantageous to the gradation of the image in the highlight portion, and in the contact development method, the low-charge toner easily adheres to the non-image latent image portion on the photosensitive drum 1. Will end up. This also has a disadvantageous effect on the gradation of the image in the highlight portion.

When the NE length 8 is 5.0 mm or more, the toner in the vicinity of the nip portion is likely to stay without being consumed. The stagnant toner continues to receive the share for a longer time than other toners, so that the charge-up of the toner easily occurs. This causes the toner charge amount to vary as in the case where the NE length 8 is less than 0.1 mm, and in this case also, the image gradation property is deteriorated.

Further, the pigment represented by the basic structural formula (1) imparts to each toner particle a property of quickly giving an electric charge to each toner particle even under a high humidity condition and a stable charging ability for a long time. It is presumed that they also have the property of It is considered that this is because the structure and charging characteristics of the pigment represented by the structural formula (1) influence the charging ability of the toner particles and the electrostatic cohesive force between the toner particles.

From the above, it is considered that by combining these two conditions, it is possible to continuously obtain a high-quality and high-gradation image even during long-term use under high humidity conditions.

In the present invention, in addition to the toner containing the pigment represented by the basic structural formula (1), C.I.
I. It preferably contains a dye classified as Solvent Yellow 162. Although the detailed reason is unknown, it is considered that the dye acts as a charging / dispersion aid to stabilize the chargeability of the toner.

In the present invention, when only the pigment represented by the basic structural formula (1) is used as a colorant, the total content thereof is 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. Good to have. Further, in the present invention, when the pigment and the dye are used together as a colorant, the total content (A) of the pigment is 0.5 with respect to 100 parts by mass of the binder resin.
To 15 parts by mass, and the dye content (B) is 0.5 to 1
It is preferable that the amount is 5 parts by mass and that A / B is 0.5 to 3.

When the total content of the pigments is less than 0.5 parts by mass, it becomes difficult to obtain a high image density, and in addition, the charging ability of the toner particles changes with the long-term use. Not preferable. In addition, when the total content of the pigment is 20 parts by mass or more, when a transfer material such as overhead transparency is used, an image with inferior transparency is obtained, which is not preferable. It is not preferable because it changes.

When the content of the dye is less than 0.5 parts by mass, the effect of adding the dye becomes insufficient, which is not preferable. On the other hand, if the content of the dye exceeds 15 parts by mass, the weather resistance of the toner is lowered and the image gradation at a low applied voltage (highlight part) is deteriorated, which is not preferable.

When the pigment / dye content ratio (A / B) is less than 0.5, the image gradation at a low applied voltage (highlight portion) is deteriorated, which is not preferable. Also, A / B is 3
If it exceeds, the effect of adding the dye becomes insufficient, which is not preferable.

The total amount of the colorant is preferably 0.5 to 20 parts by mass, more preferably 3 to 10 parts by mass, relative to 100 parts by mass of the binder resin, from the viewpoint of obtaining proper image density and dispersibility. Good part.

The toner of the present invention is 0.9 in the circularity distribution of particles measured by a flow type particle image analyzer.
The average circularity of 50 to 0.998 is preferable, and the average circularity of 0.960 to 0.995 is more preferable.

In the contact developing method, the toner layer carried on the surface of the toner carrier comes into contact with the surface of the electrostatic latent image carrier. Therefore, as compared with the non-contact developing method, flattening and damage of the toner particles are likely to occur. The flat and damaged toner particles have different charging characteristics and behave differently from normal toner particles during development, so that it is difficult to obtain a high gradation image.

As a result of detailed examination, the present inventors have found that the average circularity of the toner and the gradation of the image have a correlation. The average circularity is measured by a flow type particle image measuring device, and is calculated by an arithmetic mean of circularity calculated by the following equation.

[0045]

[Equation 1]

In the above equation, the perimeter of the particle image is the length of the contour line obtained by connecting the edge points of the binarized particle image, and the perimeter of the equivalent circle is binarized. The length of the outer circumference of a circle having the same area as the particle image.

When the average circularity is less than 0.950, the toner layer comes into contact with the surface of the electrostatic latent image carrier to cause flattening and damage of the toner particles. Therefore, it is difficult to obtain a high gradation image. When the average circularity exceeds 0.998, triboelectric charging between toner particles becomes insufficient, resulting in an image with poor gradation.

In the present invention, as a method for producing the toner having the above-mentioned specific average circularity, for example, the toner is produced by controlling the spheroidizing condition when spheronizing the toner particles produced by the pulverizing method. And a method of producing a toner by controlling production conditions when producing toner particles by a polymerization method.

As a method of spheroidizing the toner particles produced by the pulverization method, a binder resin and a colorant, and if necessary, a toner constituent material such as a release agent and a charge control agent are added to a Henschel mixer and a media disperser. Such as a dry mixer to uniformly disperse and mix, the resulting mixture is melt-kneaded using a kneader such as a pressure kneader and extruder, after cooling the resulting kneaded product, a crusher such as a hammer mill Coarsely pulverize using a crusher, and the resulting coarsely crushed product is crushed by colliding with a target under a jet stream to pulverize it.Finely pulverize using a pulverizer, and then remove coarse powder and fine powder by classification using a classifier. Then adjust the particle size distribution. Particles having a controlled particle size distribution are, for example, a hot water bath method in which toner particles are dispersed and heated in water; a heat treatment method in which toner particles are passed through a hot air flow; or an impact force by mechanical energy is applied to toner particles. Spheronization is performed by the mechanical impact method. The circularity of the toner can be adjusted by appropriately controlling the processing conditions such as the processing temperature, the processing time, and the processing energy when the spheroidizing process is performed.

As a method for producing toner particles by a polymerization method, a colorant, and optionally a toner constituent material such as a releasing agent and a charge control agent, are added together with a polymerization initiator in a polymerizable monomer, and a homogenizer and The monomer composition uniformly dissolved or dispersed by a mixer such as a sonic disperser is dispersed by a homomixer in an aqueous phase containing a dispersion stabilizer. The granulation is stopped when the droplets of the monomer composition have the desired toner particle size. After that, stirring may be performed to the extent that the particle state is maintained and the particles are prevented from settling due to the action of the dispersion stabilizer. Polymerization temperature is 40 ° C or higher, generally 50 to 90 ° C
Polymerization is performed by setting the temperature to. For the purpose of adjusting the molecular weight distribution, the temperature may be raised in the latter half of the polymerization reaction, and further in the latter half of the reaction to remove unreacted polymerizable monomers and byproducts.
Alternatively, the aqueous medium may be partially distilled off after the reaction is completed.
After the reaction is completed, the produced toner particles are collected by washing and filtration and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by mass of water as a dispersion medium with respect to 100 parts by mass of the monomer composition.

By controlling the polymerization conditions such as the kind and amount of the dispersion stabilizer, the stirring conditions, the pH of the aqueous phase and the polymerization temperature when the toner particles are produced by the above-mentioned polymerization method,
The circularity of the toner can be adjusted.

In the present invention, the toner circularity distribution is
It is measured as follows using a flow type particle image analyzer "FPIA-1000" (manufactured by Toa Medical Electronics Co., Ltd.).

For the measurement, fine dust was removed through a filter, and as a result, the measurement range (for example, equivalent circle diameter of 0.60 μm or more and 159.21 μm) was measured in water of 10 ⁻³ cm ^3.
The surface-active agent (preferably Contaminone manufactured by Wako Pure Chemical Industries, Ltd.) is added to ion-exchanged water having a particle number of less than 20 (m.
About 10 ml of solution prepared by adding 0.5% by mass (20 ° C)
Then, about 0.02 g of the measurement sample is added and uniformly dispersed to prepare a sample dispersion liquid. As a means for dispersing, an ultrasonic disperser “UH-50” manufactured by Estemte (a vibrator is
mm titanium alloy chip) is used. The dispersion time is 5 minutes or more, and at this time, the dispersion medium is appropriately cooled so that the temperature of the dispersion medium does not exceed 40 ° C. The circularity distribution of particles having a circle equivalent diameter of 0.60 μm or more and less than 159.21 μm is measured using the above flow type particle image analyzer.

The outline of the measurement is "F" issued by Toa Medical Electronics Co., Ltd.
PIA-1000 ”catalog (June 1995 version),
Operation manual for measuring device and JP-A-8-136439
Although it is described in Japanese Patent Publication No. JP-A-2003-242, it is as follows.

The sample dispersion is passed through a flat and flat transparent flow cell (thickness of about 200 μm) (spreading along the flow direction). 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. Two
It is taken as a three-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. Further, the circularity of each particle is calculated by dividing the perimeter of a circle (equivalent circle) having the same area as the two-dimensional image of each particle by the perimeter of the two-dimensional image of each particle.

As shown in Table 1, the results (frequency% and cumulative%) can be obtained by dividing the range of 0.06 to 400 μm into 226 channels (divided into 30 channels for one octave). In the actual measurement, the equivalent circle diameter is 0.
Particles are measured in the range of 60 μm or more and less than 159.21 μm.

[0057]

[Table 1]

As the binder resin of the toner according to the present invention,
Homopolymers of styrene and its substitution products such as polystyrene and polyvinyltoluene; styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, 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-vinyl methyl ketone copolymer , Styrene Styrene-based copolymers such as diene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, Examples thereof include polypropylene, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, paraffin wax and carnauba wax.
These can be used alone or as a mixture.

Known monomers are preferably used in the method of directly obtaining the toner by the polymerization method. Specifically, styrene-based monomers such as styrene, o- (m-, p-) methylstyrene, m- (p-) ethylstyrene; methyl (meth) acrylate, ethyl (meth) acrylate, ( Propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (Meth) acrylic acid ester-based monomers such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ene-based monomers such as butadiene, isoprene, cyclohexene, (meth) acrylonitrile, and acrylic acid amide Is preferably used. These may be used alone or in combination of two or more, but generally, they are generally published in "Polymer Handbook", 2nd Edition, III-P139-192 (John.
A monomer is appropriately mixed and used so that the theoretical glass transition temperature (Tg) described in Wiley & Sons) is 40 to 85 ° C.

Further, in the method of obtaining the toner particles by using the polymerization method, it is particularly preferable to add the polar resin at the same time from the viewpoint that the polymerization reaction of the polymerizable monomer can be carried out without hindrance. As the polar resin used in the present invention, a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a polyester resin and an epoxy resin are preferably used. It is particularly preferable that the polar resin does not contain an unsaturated group capable of reacting with the monomer in the molecule.

The polymerization initiator used in the present invention includes
For example, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2 ′ -Azobis-4-methoxy-2,
Azo-based polymerization initiators such as 4-dimethylvaleronitrile and azobisisobutyronitrile, benzoyl peroxide,
Methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, 2,
Peroxide-based polymerization initiators such as 4-dichlorobenzoyl peroxide and lauryl peroxide are used.

The amount of the polymerization initiator added varies depending on the desired degree of polymerization, but is generally 0.5 to 10 parts by mass with respect to 100 parts by mass of the monomer. The type of the initiator is slightly different depending on the polymerization method, but it may be used alone or in combination with reference to the 10-hour half-life temperature.

In order to control the degree of polymerization, known cross-linking agents, chain transfer agents, polymerization inhibitors and the like can be further added and used.

When the direct polymerization method is used as the toner manufacturing method of the present invention, the dispersant used is, for example, an inorganic oxide such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate or carbonate. Examples thereof include magnesium, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, magnetic materials, and ferrite.
As the organic compound, for example, polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, starch and the like are used by dispersing in an aqueous phase. These dispersants include the polymerizable monomer 10
It is preferable to use 0.2 to 2.0 parts by weight with respect to 0 parts by weight.

As these dispersants, commercially available products may be used as they are, but in order to obtain dispersed particles having a fine and uniform particle size, finely divided compounds are produced by stirring at high speed in a dispersion medium. Can also be used. For example,
In the case of tricalcium phosphate, a dispersant suitable for the suspension polymerization method can be obtained by mixing an aqueous sodium phosphate solution and an aqueous calcium chloride solution under high speed stirring. In addition, 0.001 to 0.
You may use together 1 mass part surfactant. Specifically, commercially available nonionic, anionic and cationic surfactants can be used, and examples thereof include sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and olein. Calcium acid or the like is preferably used.

A low softening point substance, so-called wax, can be used in the toner of the present invention, if necessary. Specifically, paraffin wax, polyolefin wax, microcrystalline wax, polymethylene wax such as Fischer-Tropsch wax, amide wax, ketone wax, higher fatty acid, long chain alcohol, ester wax and graft compounds and block compounds thereof Examples of such derivatives include those having a sharp maximum endothermic peak of the DSC endothermic curve from which low molecular weight components have been removed.

In the present invention, the DSC endothermic curve is measured using, for example, "DSC-7" manufactured by Perkin Elmer. 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 was used as a sample and an empty pan was set as a control, and the temperature rising rate was 10 ° C./min. Measure with.

Examples of waxes preferably used in the present invention include linear alkyl alcohols having 15 to 100 carbon atoms, linear fatty acids, linear acid amides, linear esters, and montan derivatives. . Also,
Those in which impurities such as liquid fatty acids have been previously removed from these waxes are also preferable.

Further, the wax preferably used is
Low molecular weight alkylene polymer obtained by radical polymerization of alkylene under high pressure or Ziegler catalyst or other catalyst under low pressure; alkylene polymer obtained by thermal decomposition of high molecular weight alkylene polymer; A low molecular weight alkylene polymer that has been separated and purified; Synthetic hydrocarbon obtained from the distillation residue of a hydrocarbon polymer obtained by the Arge process from a synthesis gas consisting of carbon monoxide and hydrogen, or by hydrogenating the distillation residue. From polymethylene wax obtained by extracting and fractionating specific components. An antioxidant may be added to these waxes.

The low softening point substance used in the present invention is DS
In the C endothermic curve, it is preferable to have an endothermic main peak in the region of 40 to 90 ° C (more preferably 45 to 85 ° C). Furthermore, the endothermic main peak has a half width of 1
A sharp-melting low softening point substance having a temperature within 0 ° C. (more preferably within 5 ° C.) is preferable. In particular, an ester wax whose low softening point substance is mainly an ester compound of a long chain alkyl alcohol having 15 to 45 carbon atoms and a long chain alkyl carboxylic acid having 15 to 45 carbon atoms is preferable.

As the ester wax, the following formula (I) is used.
Examples include those formed from the compounds represented by (V) to (V).

[0072]

[Chemical 5]

(In the formula, a and b are integers of 0 to 4,
a + b is 4. R ¹ and R ² are organic groups having 1 to 40 carbon atoms, and the difference in carbon number between R ¹ and R ² is 3 or more. m
And n are integers of 0 to 25, and m and n cannot be 0 at the same time. )

[0074]

[Chemical 6]

(In the formula, a and b are integers of 0 to 3,
a + b is 1 to 3. R¹And R²Has 1 to 4 carbon atoms
R is an organic group of 0¹And R²The difference in carbon number between
It R ³Is a hydrogen atom or an organic group having 1 or more carbon atoms.
However, when a + b = 2, R³Either one is carbon
An organic group whose number is 1 or more. k is an integer of 1 to 3.
m and n are integers from 0 to 25, and m and n are 0 at the same time.
It never happens. )

[0076]

[Chemical 7]

(In the formula, R ¹ and R ³ are organic groups having 6 to 32 carbon atoms, and R ¹ and R ³ may or may not be the same. R ² is 1 to 20 carbon atoms. Represents an organic group having.)

[0078]

[Chemical 8]

(In the formula, R ¹ and R ³ are organic groups having 6 to 32 carbon atoms, and R ¹ and R ³ may or may not be the same. R ² is —CH ₂ CH _{2 OC 6 H 4 OCH 2 CH 2} -,

[0080]

[Chemical 9]

Or — (CH ₂ ) _n —. m is 1 to 1
The integer of 0 and n show the integer of 1-20. )

[0082]

[Chemical 10]

(In the formula, a is an integer of 0 to 3, and b is 1
Is an integer of 4 and a + b is 4. R ¹ is an organic group having 1 to 40 carbon atoms. m and n are integers of 0 to 25, and m and n cannot be 0 at the same time. )

Specifically, the following ester waxes are preferably used.

[0085]

[Chemical 11]

[0086]

[Chemical 12]

Ester Wax 5 CH _3- (CH ₂ ) ₂₀ --COO-(CH ₂ ) ₂₁ --CH ₃ Ester Wax 6 CH _3- (CH ₂ ) ₁₆ --COO-(CH ₂ ) ₂₁ --CH ₃ Ester Wax 7 _{CH 3 - (CH 2) 39} -COO- (CH 2) 17 -CH 3 ester wax _{8 CH 3 - (CH 2)} 20 -COO- (CH 2) 17 -CH 3

[0088]

[Chemical 13]

When the ester wax having the above structural formula is used, good transparency is exhibited and good fixing property is exhibited.

The low softening point substance is preferably contained in the toner particles in an amount of preferably 3 to 40 parts by mass, more preferably 5 to 35 parts by mass with respect to 100 parts by mass of the binder resin.
When the content of the low softening point substance is less than 5 parts by mass, it is difficult to obtain sufficient high temperature offset resistance, and when the image is fixed on both surfaces of the transfer material, the first ( Surface (image) surface offset may occur.

When the content of the low softening point substance exceeds 40 parts by mass, when toner particles are manufactured by a pulverization method at the time of manufacturing the toner, fusion of the toner component in the toner manufacturing apparatus is likely to occur. When the toner particles are produced by the polymerization method, the granulation property is deteriorated during granulation, and the toner particles are likely to coalesce with each other.

To the toner of the present invention, other colorants such as yellow, magenta, cyan and black colorants can be used in combination within the range that does not impair the effects of the present invention.

As the yellow colorant, specifically, compounds represented by condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds and allylamide compounds can be used. More specifically, C.I. I. Pigment Yellow 12, 13, 14, 1
5, 17, 62, 74, 83, 109, 110, 11
1,129,147,168 etc. are used suitably.

Specific examples of the magenta colorant include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. . More specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7,
23, 48: 2, 48: 3, 48: 4, 57: 1, 8
1: 1, 122, 144, 146, 166, 169, 1
77, 184, 185, 202, 206, 220, 22
1, 254 and the like are preferable.

Specific examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. More specifically, C.I. I. Pigment Blue 1, 7, 15, 15:
1, 15: 2, 15: 3, 15: 4, 60, 62, 66
Etc. are preferred.

These colorants may be used alone or in combination, and may be used in the state of solid solution.

Carbon black can be used as the black colorant.

In the case of color toner, the colorant of the present invention is
It is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The amount of the colorant added is
It is used by adding 0.5 to 20 parts by mass to 100 parts by mass of the binder resin.

A charge control agent can be used in the toner of the present invention, if necessary.

The charge control agent used in the present invention includes
Although known compounds can be used, in the case of color toner, a charge control agent which is colorless and has a high charging speed of the toner and which can stably maintain a constant charge amount is particularly preferable.

Specific compounds include, as negative compounds, salicylic acid, naphthoic acid, dicarboxylic acids, metal compounds of their derivatives, polymeric compounds having sulfonic acid and carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds. , Calixarene and the like can be used, and as a positive system, a quaternary ammonium salt, a polymer type compound having a side chain of the quaternary ammonium salt, a guanidine compound, an imidazole compound and the like are preferably used.

The charge control agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin. However, in 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 with the blade member or the sleeve member.

In the toner of the present invention, it is possible to add organic or inorganic fine particles which are generally widely known as external additives. Specifically, examples of the inorganic fine particles include metal oxides (aluminum oxide, titanium oxide,
Strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), Fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica and the like can be used. Examples of the organic fine particles include styrene, acrylic acid, methyl methacrylate, butyl acrylate, obtained by emulsion polymerization or spray drying.
A homopolymer or copolymer of a monomer component used in a binder resin for toner such as 2-ethylhexyl acrylate can be used. Moreover, it is also possible to use a plurality of types of these fine particles in combination, if necessary.

Next, an image forming method of the present invention and an image forming apparatus for carrying out the method will be described with reference to the drawings.

As a condition of the developing step in the image forming method of the present invention, it is essential that the toner carrier and the surface of the photoconductor which is the electrostatic latent image carrier are in contact with each other.

An elastic roller is used as the toner carrier,
A method may be used in which the surface of the elastic roller or the like is coated with toner and the surface of the photosensitive member is brought into contact with the toner. In this case, development is performed by an electric field acting between the photoconductor and the elastic roller facing the photoconductor surface via the toner. Therefore, it is necessary that the surface of the elastic roller or the vicinity of the surface has an electric potential, and the electric field is present in a narrow gap between the surface of the photoconductor and the surface of the toner carrier. Therefore, it is possible to use a method in which the elastic rubber of the elastic roller is resistance-controlled in a medium resistance region to prevent electric conduction with the surface of the photoconductor and maintain an electric field, or a thin insulating layer is provided on the surface layer of the conductive roller. . Further, it is possible to adopt a configuration in which a conductive resin sleeve in which the side facing the surface of the photoconductor is coated with an insulating material is provided on the conductive roller, or a conductive layer is provided on the side not facing the photoconductor with the insulating sleeve. . Also,
It is also possible to use a rigid roller as the toner carrier and make the photoconductor flexible such as a belt. The roller as a toner carrier has a resistance value of 10 ² to 10 ⁹
The range of Ω · cm is preferable.

When the surface shape of the toner carrier is set to have a surface roughness Ra (μm) of 0.2 to 3.0, 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. . When it is 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 increases, Since the chargeability of the toner is also improved, the image quality is synergistically improved. On the other hand, the surface roughness Ra is 0.2
If it is smaller than this, it becomes difficult to control the toner coat amount.

In the present invention, the surface roughness Ra of the toner carrier is based on JIS surface roughness "JISB 0601", and a surface roughness measuring device ("Surfcoder S" manufactured by Kosaka Laboratory Ltd.) is used.
E-30H "). Specifically, a 2.5 mm portion having a measurement length a in the direction of the center line is extracted from the roughness curve, the center line of this extracted portion is the X axis, the direction of longitudinal magnification is the Y axis, and the roughness curve is When represented by y = f (x), the value obtained by the following equation is expressed in micrometers (μm).

[0109]

[Equation 2]

In the image forming method of the present invention, the toner carrier may rotate in the same direction as the peripheral speed of the photosensitive member,
It may rotate in the opposite direction. When the rotation is in the same direction, the peripheral speed of the toner carrier is 1.0 with respect to the peripheral speed of the photoconductor.
It is preferable to set it to be 5 to 3.0 times.

When 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.
If the peripheral speed ratio exceeds 3.0, deterioration of the toner due to mechanical stress and toner sticking to the toner carrier occur and are promoted, which is not preferable.

As the above-mentioned photoconductor, a-Se, CdS,
A photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as ZnO ₂ , OPC, or a-Si is preferably used. Further, the binder resin of the organic photosensitive layer in the OPC photosensitive member is not particularly limited. Of these, polycarbonate resins, polyester resins, and acrylic resins are particularly preferable because they are excellent in transferability and are less likely to cause fusion of the toner to the photosensitive member and filming of the external additive.

Next, the image forming method of the present invention will be described below with reference to the accompanying drawings.

FIG. 3 is a schematic configuration diagram of an example of an apparatus for carrying out the image forming method of the present invention. In FIG. 3, reference numeral 10 is a primary charging member that contacts the photosensitive drum 1 to perform direct charging. Rollers 11 to 13 are bias power sources, 15 is a transfer material such as paper, 16 is a transfer member, 17 is a fixing pressure roller, 18 is a fixing heating roller, and 19 is a cleaner. The same reference numerals are attached.

A bias power source 11 is connected to the charging roller 10 so as to uniformly charge the surface of the photosensitive drum 1. The developing device 7 accommodates the toner 4 in a toner container 5, and includes a developing sleeve 2 which is a toner carrier which comes into contact with the photosensitive drum 1 which is an electrostatic latent image carrier and rotates in the arrow direction. Further, an elastic regulating blade 3 and a toner 4 which are toner regulating members for regulating toner and imparting electric charge.
Is also attached to the developing sleeve 2, and a coating roller 9 that rotates in the direction of the arrow is provided to charge the toner by friction with the developing sleeve 2. A developing bias power source 13 is connected to the developing sleeve 2. A bias power source (not shown) is also connected to the coating roller 9, and a voltage is applied to the negative side of the developing bias when the negative charging toner is used, and to the positive side of the developing bias when the positive charging toner is used. Is set.

A transfer bias power source 12 having a polarity opposite to that of the photosensitive drum 1 is connected to the transfer member 16.

Here, the photosensitive drum 1 and the developing sleeve 2
The length of the contact portion in the rotating direction, that is, the so-called developing nip width is preferably 0.2 mm or more and 8.0 mm or less. 0.
If it is less than 2 mm, the amount of development is insufficient and a satisfactory image density cannot be obtained, and the transfer residual toner is not sufficiently collected. 8.0 mm
If it exceeds the range, the toner supply amount becomes excessive and the fog is apt to be deteriorated, and the abrasion of the photosensitive drum 1 is also adversely affected. A so-called elastic roller having an elastic layer on its surface is preferably used as the developing sleeve 2 which is a toner carrier. The hardness of the material of the elastic layer used for the elastic roller is 30 to 60 degrees (asker-C /
A load of 1 kg) is preferably used.

The resistance of the developing sleeve 2 is preferably in the range of about 10 ² to 10 ⁹ Ωcm in terms of volume resistance value.
When it is lower than 0 ² Ωcm, for example, when there is a pinhole or the like on the surface of the photosensitive drum 1, an overcurrent may flow. On the other hand, when it is higher than 10 ⁹ Ωcm, toner charge-up due to triboelectric charging is apt to occur and the image density is apt to be lowered.

The toner coat amount on the developing sleeve 2 is
It is preferably 0.1 mg / cm ² or more and 1.5 mg / cm ² or less. 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 1.5 mg / cm ^2, it becomes difficult to uniformly triboelectrically charge all the individual toner particles, which is a cause of deterioration of fog. Become. Furthermore, 0.2 mg /
cm ² or less is more preferable.

The toner coating amount is controlled by the elasticity regulating blade 3, which is in contact with the developing sleeve 2 via the toner layer. The contact pressure between the regulating blade 3 and the developing sleeve 2 at this time is 0.05 N / cm or more and 0.5 N / c or more as a linear pressure in the developing sleeve 2 generatrix direction.
m or less is a preferable range.

The linear pressure is a load applied per length of the blade 3, and for example, a load of 1.2 N is applied to the blade 3 having a contact length of 1 m to bring it into contact with the developing sleeve 2. In that case, the linear pressure is 1.2 N / m. 0.
If it is less than 05 N / cm, uniform triboelectric charging becomes difficult in addition to the control of the toner coat amount, which causes deterioration of fog. On the other hand, when it is more than 0.5 N / cm, the toner particles are excessively loaded, and thus the deformation of the particles and the fusion of the toner to the regulating blade 3 or the developing sleeve 2 are likely to occur, which is not preferable.

The free end portion of the elastic regulating blade 3 may have any shape as long as it gives a preferable NE length. For example, the free end portion may have an L-shape bent near the tip, other than a straight cross section. Those having a shape in which the vicinity of the tip swells in a spherical shape are preferably used.

As the toner regulating member, a rigid metal blade or the like may be used in addition to the elastic regulating blade 3 for applying the toner under pressure. When the elasticity regulating blade 3 is used as the toner regulating member, it is preferable to select a friction charging series material suitable for charging the toner to a desired polarity, such as rubber such as silicone rubber, urethane rubber and NBR. Elastic bodies, synthetic resin elastic bodies such as polyethylene terephthalate, and metallic elastic bodies such as stainless steel, steel and phosphor bronze can be used. Further, it may be a complex thereof.

When durability is required for the elastic regulating blade 3 and the developing sleeve 2, resin or rubber may be attached to the metallic elastic body so that the sleeve abutting portion may be abutted.
Those coated with a coating are preferred.

Further, an organic substance or an inorganic substance may be added to the elasticity regulating blade 3 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, surfactants and the like. In particular, when the elastic body is a molded body such as rubber or resin, silica, alumina, titania,
It is also preferable to contain fine powder of metal oxide such as tin oxide, zirconia, and zinc oxide, carbon black, and a charge control agent generally used for toner.

Further, by applying a DC electric field and / or an AC electric field to the toner regulating member, the uniform thin layer coating property and the uniform charging property are further improved due to the loosening effect on the toner, and the sufficient image density is obtained. Can be achieved and good quality images can be obtained.

In FIG. 3, the photosensitive drum 1 rotating in the direction of the arrow is uniformly charged by the primary charging member. In the present example, the primary charging member is a charging roller 10 having a central core metal 10b and a conductive elastic layer 10a forming the outer periphery thereof as a basic configuration. The charging roller 10 is brought into contact with one surface of the photosensitive drum 1, which is an electrostatic latent image carrier, with a suppression force, and is driven to rotate as the photosensitive drum 1 rotates.

A preferable process condition when the charging roller 10 is used is that the contact pressure of the roller is 0.05 to 5 N /
The applied voltage may be a DC voltage or a DC voltage superimposed with an AC voltage, and is not particularly limited. However, when a DC voltage superimposed with an AC voltage is used, the AC voltage is 0.5. ~ 5dVpp, AC frequency = 5
0 Hz to 5 kHz, DC voltage = ± 0.2 to ± 1.5 kV
Therefore, when a DC voltage is used, the DC voltage = ± 0.2
Is ± 5 kV. In the present invention, the applied voltage of only the DC voltage is preferably used.

As charging means other than the charging roller 10,
There are a method using a charging blade and a method using a conductive brush. These contact charging means have an effect that a high voltage becomes unnecessary and ozone generation is reduced as compared with non-contact corona charging. As a material of the charging roller and the charging blade as the contact charging means, conductive rubber is preferable, and a releasing film may be provided on the surface thereof.
As the releasable coating, nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride)
Are applicable.

After the step of charging the electrostatic latent image carrier, an electrostatic latent image corresponding to an information signal is formed on the photosensitive drum 1 by, for example, exposure 14 from the light emitting element, and the developing sleeve 2
The toner develops the electrostatic latent image into a visible image at a position where the electrostatic latent image comes into contact with. Further, 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 the photosensitive drum 1, it is possible to faithfully develop a dot latent image without disturbing the latent image. Becomes The visible image is transferred to the transfer material 15 by the transfer member 16 and passes between the heating roller 18 and the pressure roller 17 to be fixed to obtain a permanent image. The heating / pressurizing fixing means is basically a heating roller 18 having a built-in heating element such as a halogen heater and an elastic pressing roller 17 pressed against the heating roller 18 as a basic structure. In addition, 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 photosensitive drum 1 without being transferred is collected by the cleaner 19 having a cleaning blade which is in contact with the surface of the photosensitive drum 1, and the photosensitive drum 1 is cleaned. It

FIG. 4 is a schematic block diagram of an example of an image forming apparatus for collectively transferring multiple toner images onto a recording material by using an intermediate transfer member in the image forming method of the present invention.

In FIG. 4, 7a to 7d are developing devices for respective colors of black, yellow, magenta, and cyan, 21 is a light source device, 22 is a laser beam, 23 is a fixing device, 24 is a developing unit, and 25 is an intermediate transfer. An intermediate transfer drum, which is a body, 25a is a conductive support, 25b is an elastic layer,
Reference numeral 26 is a bias power source, 27 is a transfer material tray, and 28 is a secondary transfer device. The same members as those in FIGS. 2 and 3 are denoted by the same reference numerals.

The surface of the photosensitive drum 1 serving as an electrostatic latent image carrier is brought into contact with the surface of the photosensitive drum 1 while rotating the rotatable charging roller 10 to which a charging bias voltage is applied as a charging member. A first electrostatic latent image is formed on the photoconductor drum 1 by the laser light 22 emitted from the light source device 21 as the exposure means, which is uniformly primary charged.
The formed first electrostatic latent image is developed with the black toner in the black developing device 7a as the first developing device provided in the rotatable developing unit 24 to form a black toner image. The black toner image formed on the photoconductor drum 1 is electrostatically primarily transferred onto the intermediate transfer drum 25 by the action of the transfer bias voltage applied to the conductive support 25 a of the intermediate transfer drum 25.
Next, in the same manner as described above, a second electrostatic latent image is formed on the surface of the photosensitive drum 1, the developing unit 24 is rotated, and the second electrostatic latent image is formed.
Of the yellow developing device 7b as a developing device for developing the yellow toner image to form a yellow toner image, and the black toner image is primarily transferred to the intermediate transfer drum 25.
The yellow toner image is electrostatically primary-transferred thereon. Similarly, the developing unit 24 is rotated to generate the third electrostatic latent image and the fourth electrostatic latent image, and the magenta toner in the magenta developing device 7c as the third developing device and the fourth developing device are used as the fourth developing device. The cyan toner in the cyan developing device 7d performs sequential development and primary transfer, and the toner images of the respective colors are primarily transferred onto the intermediate transfer drum 25. Intermediate transfer drum 2
The multiple toner image primarily transferred onto the transfer material 5 is electrostatically and collectively transferred onto the transfer material 15 by the effect of the transfer bias voltage from the secondary transfer device 28 located on the opposite side via the transfer material 15. Next is transcribed. The multiple toner image secondarily transferred onto the transfer material 15 is heat-fixed on the transfer material 15 by a fixing device 23 having a heating roller 17 and a pressure roller 18. The transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer is collected by the cleaner 19 having a cleaning blade that contacts the surface of the photosensitive drum 1, and the photosensitive drum 1 is cleaned.

The primary transfer from the photosensitive drum 1 to the intermediate transfer drum 25 is performed by the intermediate transfer drum 2 as a primary transfer device.
A transfer current is obtained by applying a bias from the bias power supply 26 to the conductive support 25a of No. 5 to transfer the toner image.

The intermediate transfer drum 25 comprises a conductive support 25a which is a rigid body, and an elastic layer 25b which covers the surface. As the conductive support 25a, a metal or alloy such as aluminum, iron, copper and stainless, and a conductive resin in which carbon or metal particles are dispersed can be used, and the shape thereof is cylindrical or cylindrical. Examples thereof include those having a shaft penetrating through the center and those having reinforcement inside the cylinder.

The elastic layer 25b is not particularly limited, but styrene-butadiene rubber, high styrene rubber, butadiene rubber, isoprene rubber, ethylene-
Propylene copolymer, nitrile butadiene rubber (NB
R), chloroprene rubber, butyl rubber, silicone rubber, fluorine rubber, nitrile rubber, urethane rubber, acrylic rubber, epichlorohydrin rubber, norbornene rubber, and other elastomer rubbers are preferably used. A resin such as a polyolefin resin, a silicone resin, a fluorine resin, a polycarbonate, or a copolymer or mixture thereof may be used.

Further, a surface layer in which lubricant powder having high lubricity and water repellency is dispersed in an arbitrary binder may be provided on the surface of the elastic layer 25b.

The lubricant is not particularly limited, but various fluororubbers, fluoroelastomers, graphite and fluorocarbons having fluorine bonded to graphite, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene. Copolymer (ETFE)
And fluorine compounds such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), silicone-based particles such as silicone resin particles, silicone rubber and silicone elastomer, polyethylene (P
E), polypropylene (PP), polystyrene (P
S), acrylic resin, polyamide resin, phenol resin, epoxy resin and the like are preferably used.

In addition, a conductive agent may be added to the binder of the surface layer in order to control the resistance. Examples of the conductive agent include various conductive inorganic particles and carbon black, ionic conductive agents, conductive resins and conductive particle dispersed resins.

The multiple toner image on the intermediate transfer drum 25 is
Secondary transfer is collectively secondary-transferred onto the transfer material 15 by the secondary transfer device 28. As the transfer device 28, a non-contact electrostatic transfer means using a corona charger or a contact electrostatic transfer means using a transfer roller and a transfer belt is used. It can be used.

The fixing device 23 is replaced by a heat roller fixing device having a heating roller 18 and a pressure roller 17, and a film in contact with the toner image on the transfer material 15 is heated to remove the toner image on the transfer material 15. And transfer material 15
It is also possible to use a film heat fixing device that heat-fixes the multiple toner images.

Instead of the intermediate transfer drum 25 as an intermediate transfer member used in the image forming apparatus shown in FIG. 4, it is also possible to use an intermediate transfer belt to collectively transfer multiple toner particles onto a recording material. A schematic configuration diagram of an apparatus using the intermediate transfer belt is shown in FIG.

In FIG. 5, 30 is an intermediate transfer belt, and 3 is
1, 1 is a roller for passing the intermediate transfer belt 30, 32 is a primary transfer roller, 33a is a secondary transfer counter roller, 33b is a secondary transfer roller, 34 to 36 are bias power sources, 39 is a cleaning charging member, and FIG. The same members as those in FIG. 4 are designated by the same reference numerals.

In the structure of FIG. 5, the toner image formed and carried on the photosensitive drum 1 passes from the primary transfer roller 32 to the intermediate transfer belt while passing through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 30. By the electric field formed by the primary transfer bias applied to 30, the primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 30.

The primary transfer bias for sequentially superposing and transferring the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 30 has a polarity opposite to that of the toner and is applied from the bias power source 34.

In the primary transfer process of the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 30,
Secondary transfer roller 33b and cleaning charging member 39
Can be separated from the intermediate transfer belt 30.

Reference numeral 33b is a secondary transfer roller, which is arranged in a separable state on the lower surface of the intermediate transfer belt 30 by bearing in parallel with the secondary transfer counter roller 33a.

The transfer of the composite color toner image transferred onto the intermediate transfer belt 30 to the transfer material 15 is performed by the secondary transfer roller 33b contacting the intermediate transfer belt 30 and the intermediate transfer belt 30 and the secondary transfer. The transfer material 15 is fed to the contact nip with the roller 33b at a predetermined timing, and the secondary transfer bias is applied from the bias power source 36 to the secondary transfer roller 33.
applied to b. By this secondary transfer bias, the composite color toner image is secondarily transferred from the intermediate transfer belt 30 to the transfer material 15.

After the image transfer onto the transfer material 15, the cleaning charging member 39 is brought into contact with the intermediate transfer belt 30, and a bias having a polarity opposite to that of the photosensitive drum 1 is applied from the bias power source 35 to transfer the image. Toner remaining on the intermediate transfer belt 30 without being transferred to the material 15 (transfer residual toner) is charged with an electric charge having a polarity opposite to that of the photosensitive drum 1. Next, the transfer residual toner is transferred to the photosensitive drum 1 in the nip portion with the photosensitive drum 1 and in the vicinity thereof, whereby the intermediate transfer belt 30 is cleaned.

The intermediate transfer belt 30 is composed of a belt-shaped base layer and a surface treatment layer provided on the base layer. The surface treatment layer may be composed of a plurality of layers.

Rubber, elastomer, and resin can be used for the base layer and the surface treatment layer. For example, as rubber and elastomer, natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, butyl rubber, ethylene-propylene rubber, ethylene-propylene terpolymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, acrylonitrile butadiene rubber, Urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, acrylic rubber, silicone rubber, fluororubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber and thermoplastic elastomer (for example, polystyrene type, polyolefin type,
One kind or two or more kinds selected from the group consisting of polyvinyl chloride type, polyurethane type, polyamide type, polyester type, fluororesin type and the like) can be used. However, the material is not limited to the above materials. Also,
As the resin, a resin such as a polyolefin resin, a silicone resin, a fluorine resin, or a polycarbonate can be used. You may use the copolymer or mixture of these resins.

As the base layer, the above-mentioned rubber, elastomer,
The resin can be used in the form of a film. Also,
A woven fabric-shaped, non-woven fabric-shaped, thread-shaped, or film-shaped core body layer may be coated with, dipped, or sprayed with the above-mentioned rubber, elastomer, or resin.

The material constituting the core layer is, for example, cotton, silk,
Natural fibers such as hemp and wool; regenerated fibers such as chitin fibers, alginic acid fibers and regenerated cellulose fibers; semi-synthetic fibers such as acetate fibers; polyester fibers, nylon fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride Synthetic fibers such as fibers, polyvinylidene chloride fibers, polyurethane fibers, polyalkylparaoxybenzoate fibers, polyacetal fibers, aramid fibers, polyfluoroethylene fibers and phenol fibers;
One or more selected from the group consisting of inorganic fibers such as carbon fibers, glass fibers and boron fibers; metal fibers such as iron fibers and copper fibers can be used. Of course, the material is not limited to the above.

Further, a conductive agent may be added to the base layer and the surface treatment layer in order to adjust the low resistance value of the intermediate transfer belt 30. Although the conductive agent is not particularly limited, for example, carbon, metal powders such as aluminum and nickel, metal oxides such as titanium oxide, and quaternary ammonium salt-containing polymethylmethacrylate, polyvinylaniline, polyvinylpyrrole, One or more selected from the group consisting of conductive polymer compounds such as polydiacetylene, polyethyleneimine, boron-containing polymer compounds and polypyrrole can be used. However, the conductive agent is not limited to the above.

Further, a lubricant may be added if necessary in order to improve the slipperiness of the surface of the intermediate transfer belt 30 and improve the transferability. The lubricant is not particularly limited, but various fluororubbers, fluoroelastomers, graphite and fluorocarbons obtained by binding fluorine to graphite, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVD).
F), ethylene-tetrafluoroethylene copolymer (E
Fluorine compounds such as TFE) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), silicone compounds such as silicone resin, silicone rubber and silicone elastomer, polyethylene (P
E), polypropylene (PP), polystyrene (P
S), acrylic resin, polyamide resin, phenol resin, epoxy resin and the like are preferably used.

Next, a schematic configuration diagram of an apparatus in which toner images of respective colors are respectively formed in a plurality of image forming sections and which are sequentially transferred onto the same transfer material will be described with reference to FIG.

In FIG. 6, 1a to 1d are photosensitive drums, 19a to 19d are cleaners, 41a to 41d are image forming sections, 42a to 42d are latent image forming means, and 43a to 4 are.
3d is a transfer discharge part, 44a to 44d are primary charging parts, 4
Reference numeral 5 is a static eliminator, 46 is a conveyor belt, 7a to 7d are developing devices, 48 is an adsorption charger, 49a to 49d are separate static eliminators and discharge parts, and 50 is a discharge port. Numbers are attached.

In the configuration of FIG. 6, first to fourth image forming portions 41a to 41d are arranged in parallel, and each image forming portion is a photosensitive drum 1a to 1a which is a dedicated electrostatic latent image carrier.
It has d. The photosensitive drums 1a to 1d are provided with latent image forming means 42a to 42d and developing devices 7a to 7 on the outer peripheral side thereof.
d, transfer discharge parts 43a to 43d, cleaner 19a to
19d and primary charging units 44a to 44d are arranged.

With this structure, first, a latent image forming means 42a forms a latent image of, for example, a yellow component color in the original image on the photosensitive drum 1a of the first image forming portion 41a. The latent image is formed into a visible image with the yellow toner of the developing device 7a, and the transfer material 1 is transferred to the transfer discharge unit 43a.
5 is transferred.

While the yellow image is being transferred to the transfer material 15 as described above, a latent image of a magenta component color is formed on the photosensitive drum 1b in the second image forming section 41b, and then the developing device 7b is operated. It is a visible image with magenta toner.
This visible image (magenta toner image) is transferred onto a predetermined position of the transfer material 15 when the transfer material 15 which has been transferred by the first image forming section 41a is carried into the transfer discharge section 42b. To be done.

Thereafter, the third and fourth steps are performed by the same method as described above.
In the image forming portions 41c and 41d of the above, cyan and black images are formed, and the same transfer material 15 is formed.
Then, the cyan color and the black color are superimposed and transferred.
When such an image forming process is completed, the transfer material 15 is conveyed to the fixing device 23 and the image on the transfer material 15 is fixed. As a result, a multicolor image can be obtained on the transfer material 15. Each photoconductor drum 1a after the transfer is completed
The residual toner 1d is removed by the cleaners 19a to 19d and is used for the subsequent latent image formation.

In the image forming apparatus, the conveyor belt 46 is used to convey the transfer material 15, as shown in FIG.
In, the transfer material 5 is conveyed from the right side to the left side, and in the conveying process, the transfer material 5 passes through each of the transfer discharge sections 43a to 43d in each of the image forming sections 41a to 41d to be transferred.

In this image forming method, from the viewpoint of easiness of processing and durability as a conveying means for conveying the transfer material 15, a conveyor belt using a mesh of tetron fiber and a polyethylene terephthalate resin, a polyimide resin,
A conveyor belt using a thin dielectric sheet such as urethane resin is used.

When the transfer material 15 passes through the fourth image forming section 41d, a DC voltage is applied to the static eliminator 45, and the transfer material 15 is transferred.
Is discharged from the conveyor belt 46, then enters the fixing device 23, the image is fixed, and the sheet is discharged from the discharge port 50.

In this apparatus, each of the plurality of image forming sections is provided with an independent electrostatic latent image carrier, and the transfer material is a belt type conveying means, and the electrostatic latent image carriers are sequentially transferred. The electrostatic latent image carrier, which is configured to be sent to the transfer unit, is provided in common with the image forming unit, and the transfer material is a drum type conveying unit, and the transfer unit of the electrostatic latent image carrier is used. May be repeatedly sent to each color to receive the transfer of each color.

In the conveyor belt system of FIG. 6, since the volume resistance is high, the conveyor belt increases the charge amount in the process of repeating transfer several times as in the color image forming apparatus. For this reason, uniform transfer cannot be maintained unless the transfer current is sequentially increased for each transfer, but the toner of the present invention has excellent transferability, and therefore even if the charge on the conveyor belt increases each time transfer is repeated. With the same transfer current, the transferability of toner in each transfer can be made uniform, and a high-quality image of high quality can be obtained.

Further, FIG. 7 shows a schematic constitutional view of another apparatus example for carrying out the image forming method of the present invention, which will be described below.

In FIG. 7, 44 is a primary charging section, 60 is a transfer drum, 61 is a gripper, 62 is a transfer charger, and 6
3a and 63b are separation chargers, 64 is a separation guide,
The same members as those in FIGS. 2 to 6 are denoted by the same reference numerals.

In the structure shown in FIG. 7, the electrostatic latent image formed on the photosensitive drum 1 by an appropriate means has developing devices 7a to 7a attached to the developing unit 24 which rotates in the direction of the arrow.
In the first developing device 7a in 7d, it is visualized by the toner. The color toner image on the photosensitive drum 1 is
It is transferred by the transfer charger 62 onto the transfer material 15 held on the transfer drum 60 by the gripper 61.
The transfer residual toner remaining on the surface of the photosensitive drum 1 after the transfer is collected by the cleaner 19 having a cleaning blade that contacts the surface of the photosensitive drum 1, and the photosensitive drum 1 is cleaned.

A corona charger or a contact charger is used as the transfer charger 62. When a corona charger is used as the transfer charger 62, a voltage of −10 kV to +10 kV is applied and the transfer current is − It is 500 μA to +500 μA. A holding member is stretched on the outer peripheral surface of the transfer drum 60,
This holding member is composed of a film-like dielectric sheet such as a polyvinylidene fluoride resin film or polyethylene terephthalate. For example, a thickness of 100 μm to 20
A sheet having 0 μm and a volume resistance of 10 ¹² to 10 ¹⁴ Ω · cm is used.

Next, as the second color, the developing unit 24 rotates and the developing device 7b faces the photosensitive drum 1. Then, it is developed with the second toner in the developing device 7b, and this toner image is also transferred onto the same transfer material 15 as described above.

Further, the third color and the fourth color are similarly performed. In this way, the transfer drum 60 is rotated a predetermined number of times while carrying the transfer material 15, and the toner images of a predetermined number of colors are transferred in multiple. The transfer current for electrostatic transfer is 1st color <2
It is preferable to increase the order of the color <third color <4th color in order to reduce the transfer residual toner remaining on the photosensitive drum 1.

When the transfer current is increased, the transferred image is disturbed, which is not preferable, but the toner of the present invention is excellent in transferability. Therefore, the second color, the third color, and the fourth color should be firmly transferred in multiple transfer. You can Therefore, an image of any color is properly formed, and a multicolored image with a sharp touch can be obtained. Further, in a full-color image, a beautiful image excellent in color reproduction can be obtained. Moreover, since it is not necessary to increase the transfer current so much, the disturbance of the image in the transfer process can be reduced. Further, when the transfer material 15 is separated from the transfer drum 60, the charge is removed by the separation chargers 63a and 63b. However, when the transfer current is large, the electrostatic attraction of the transfer material 15 to the transfer drum 60 becomes large and the transfer material 15 is separated. The current cannot be separated unless the current is increased. Then,
Since the polarity is opposite to that of the transfer current, the toner image is disturbed and the toner is scattered from the transfer material, which contaminates the inside of the image forming apparatus. Since the toner of the present invention is easy to transfer,
It is not necessary to increase the separation current, the separation can be facilitated, and as a result, the disturbance of the image at the time of separation and the toner scattering can be prevented. Therefore, the toner of the present invention is particularly preferably used in an image forming method for forming a multicolor image or a full color image having a multiple transfer step.

The multi-transferred transfer material 15 is separated from the transfer drum 60 by the separation chargers 63a and 63b, fixed by the heating / pressurizing roller fixing device 23, and color-mixed at the time of fixing to obtain a full-color copy image. Becomes

FIG. 8 shows another example of the apparatus for carrying out the image forming method of the present invention, in which the four color toner images primarily transferred onto the intermediate transfer drum are secondarily transferred onto the transfer material all together. A schematic configuration diagram of an image forming apparatus using a transfer belt as a secondary transfer means is shown.

In the apparatus shown in FIG. 8, the developing devices 7a ...
Toners of respective colors of black, yellow, cyan, and magenta are introduced into 7d to develop the electrostatic latent image formed on the photosensitive drum 1, and the toner images of respective colors are transferred to the photosensitive drum 1.
Formed on. The photosensitive drum 1 is made of a-Se, Cds,
Photoconductive insulating material layer 7 such as ZnO ₂ , OPC, a-Si
It has 1b and is rotated in the direction of the arrow by a driving device (not shown). A photosensitive body having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used for the photosensitive layer 71a.

As the organic photosensitive layer, the photosensitive layer contains a charge generating substance and a substance having a charge transporting property in the same layer.
It may be a single layer type or a function-separated type photosensitive layer in which the charge transport layer contains a charge generation layer as a component. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated in this order on a conductive substrate is one of preferred examples.

Polycarbonate resin, polyester resin, and acrylic resin are particularly preferable as the binder resin of the organic photosensitive layer because of good transferability and cleaning property, poor cleaning, fusing of toner to the photosensitive member, and filming of external additives. Hard to happen.

In the charging step, there are a method of non-contact with the photosensitive drum 1 using a corona charger and a contact type method using a roller or the like. In order to reduce the amount of ozone and generate ozone, a contact type as shown in FIG. 8 is preferably used.

The charging roller 10 has a basic core metal 10b and a conductive elastic layer 10a formed on the outer periphery thereof. The charging roller 10 is pressed against the surface of the photosensitive drum 1 with a pressing force and is driven to rotate as the photosensitive drum 1 rotates.

Preferred process conditions when the charging roller 10 is used are the same as those of the apparatus shown in FIG.

The toner image on the photosensitive drum 1 is transferred to the intermediate transfer drum 25 to which a voltage (for example, ± 0.1 ± 5 kV) is applied. The surface of the photosensitive drum 1 after the transfer is cleaned by a cleaner 19 having a cleaning blade.

The intermediate transfer drum 25 is arranged in parallel with the photosensitive drum 1 so as to be in contact with the lower surface of the photosensitive drum 1, and is arranged at the same peripheral speed as the photosensitive drum 1 in the counterclockwise direction indicated by the arrow. Rotate in the direction.

The first formed and carried on the surface of the photosensitive drum 1.
Color toner images are transferred to the photosensitive drum 1 and the intermediate transfer drum 25.
The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer drum 25 by the electric field formed in the transfer nip area by the applied transfer bias to the intermediate transfer drum 25 while passing through the transfer nip portion where the and are in contact with each other.

If necessary, the removable cleaning means 72 cleans the surface of the intermediate transfer drum 25 after the toner image is transferred onto the transfer material 15. When there is a toner image on the intermediate transfer drum 25, the cleaning unit 72 uses the intermediate transfer drum 25 so as not to disturb the toner image.
Separated from the surface.

A transfer means is arranged in parallel with the intermediate transfer drum 25 so as to be in contact with the lower surface of the intermediate transfer drum 25. The transfer unit is, for example, a transfer roller or a transfer belt, and rotates in the clockwise direction indicated by an arrow at the same peripheral speed as the intermediate transfer drum 25. The transfer means 73 may be arranged so as to be in direct contact with the intermediate transfer drum 25, or a belt or the like may be arranged so as to be in contact between the intermediate transfer drum 25 and the transfer means.

When the transfer means is a transfer roller, it has a basic structure of a central cored bar and a conductive elastic layer forming the outer periphery thereof.

As the intermediate transfer drum and transfer roller,
Common materials can be used. By setting the volume specific resistance value of the elastic layer of the transfer roller to be smaller than the volume specific resistance value of the elastic layer 25b of the intermediate transfer drum 25, the voltage applied to the transfer roller can be reduced, and the transfer material 15 can be satisfactorily formed. It is possible to form a toner image and prevent the transfer material 15 from being wound around the intermediate transfer drum 25. In particular, it is particularly preferable that the volume specific resistance value of the elastic layer 25b of the intermediate transfer drum 25 is 10 times or more the volume specific resistance value of the elastic layer of the transfer roller.

The hardness of the intermediate transfer drum and transfer roller is
It is measured according to JIS K-6301. The intermediate transfer drum 25 used in the present invention is preferably composed of an elastic layer 25b belonging to the range of 10 to 40 degrees, while the hardness of the elastic layer of the transfer roller is the intermediate transfer drum 25.
It is preferable that the elastic layer 25b is harder than the elastic layer 25b and has a value of 41 to 80 degrees in order to prevent the transfer material 15 from being wound around the intermediate transfer drum 25. When the hardness of the intermediate transfer drum 25 and the transfer roller are opposite, a recess is formed on the transfer roller side, and the transfer material 15 is likely to be wound around the intermediate transfer drum 25.

In FIG. 8, below the intermediate transfer drum 25,
A transfer belt 73 is arranged. The transfer belt 73 is
It is wound around two rollers, that is, a bias roller 74 and a tension roller 75, arranged in parallel to the axis of the intermediate transfer drum 25, and is driven by a driving means (not shown). The transfer belt 73 is a tension roller 75.
Since the bias roller 74 side is configured to be movable in the arrow direction with the side being the center, the intermediate transfer drum 25
Can be contacted and separated from below in the direction of the arrow. The bias roller 74 includes a bias power supply 76 for secondary transfer.
Is applied with a desired secondary transfer bias, while the tension roller 75 is grounded.

Next, as the transfer belt 73, for example,
Carbon is dispersed in a thermosetting urethane elastomer to a thickness of about 300 μm and a volume resistivity of 10 ⁸ to 10 ¹² Ω · cm.
Fluorine rubber 20μ after controlling to (1kV applied)
A rubber belt whose m and volume resistivity are controlled to 10 ¹⁵ Ω · cm (when 1 kV is applied) is used. The outer diameter is 80
× A tube shape with a width of 300 mm.

A tension of about 5% is applied to the transfer belt 73 by the bias roller 74 and the tension roller 75 described above.

The transfer belt 73 is rotated at a constant speed or a peripheral speed different from that of the intermediate transfer drum 25. The transfer material 15 is conveyed between the intermediate transfer drum 25 and the transfer belt 73, and at the same time, the bias power source 76 applies a bias having a polarity opposite to that of the frictional charge of the toner to the transfer belt 73. The upper toner image is transferred to the surface side of the transfer material 15.

As the material of the transfer rotary member, the same material as that of the charging roller can be used, and the preferable transfer process condition is that the contact pressure of the roller is 5 to 500 g / c.
m, the DC voltage is ± 0.2 to ± 10 kV.

For example, the conductive elastic layer 74b of the bias roller 74 is made of polyurethane or ethylene-propylene-diene terpolymer (E) in which a conductive material such as carbon is dispersed.
It is made of an elastic body having a volume resistance of about 10 ⁶ to 10 ¹⁰ Ωcm such as PDM). A bias is applied to the cored bar 74a by a constant voltage bias power source. The bias condition is preferably ± 0.2 to ± 10 kV.

Next, the transfer material 15 is conveyed to a fixing device 23 having a heating roller 18 containing a heating element such as a halogen heater and an elastic pressure roller 17 pressed against the heating roller 18 with a pressing force. The toner image is transferred to the transfer material 1 by passing between the heating roller 18 and the pressure roller 17.
5 is fixed under heat and pressure. A method of fixing with a heater through a film may be used.

[0198]

EXAMPLES The present invention will be specifically described below, but the present invention is not limited thereto.

Example 1 To 400 parts by mass of ion-exchanged water, 450 parts by mass of a 0.1 M Na ₃ PO ₄ aqueous solution was added, and after heating to 50 ° C., a TK homomixer (made by Tokushu Kika Kogyo Co., Ltd.) was used. ) Was used for stirring at 10,000 rpm. To this was added 68 parts by mass of 1.0 M-CaCl ₂ aqueous solution to obtain an aqueous medium containing a calcium phosphate salt.

On the other hand, monomer:   Styrene 78 parts by mass   22 parts by mass of n-butyl acrylate Colorant:   C. I. Pigment Yellow 180 3 parts by mass   C. I. Solvent Yellow 162 4 parts by mass Charge control agent:   Metallic salicylate compound 1 part by mass Polar resin:   Saturated polyester 10 parts by mass     (Acid value 10, peak molecular weight; 15,000) Release agent:   Behenyl stearate 15 parts by mass Crosslinking agent:   Divinylbenzene 1.2 parts by mass

The above formulation was heated to 50 ° C. and uniformly dissolved and dispersed at 9000 rpm using a TK homomixer (made by Tokushu Kika Kogyo). 3 parts by mass of lauryl peroxide (polymerization initiator) was dissolved in this to prepare a polymerizable monomer composition.

The above polymerizable monomer composition was added to the aqueous medium and stirred at 8000 rpm with a TK type homomixer at 50 ° C. under N ₂ atmosphere to prepare a polymerizable monomer composition. Grained.

Then, while stirring with a paddle stirring blade, the temperature was raised to 60 ° C. in 2 hours and the reaction was carried out for 4 hours. Then, the temperature was raised to 80 ° C. at a temperature rising rate of 40 ° C./hr, and the reaction was performed for 4 hours. After completion of the polymerization reaction, the residual monomer was distilled off under reduced pressure,
After cooling, hydrochloric acid was added and the mixture was stirred for 6 hours. After that, the toner particles (1) are filtered, washed with ion-exchanged water, and dried.
Got

With respect to 100 parts by mass of the toner particles (1), a hydrophobic silica fine powder (BET specific surface area: 300 m ² ) treated with hexamethyldisilazane as a flow improver.
/ G) of 1.2 parts by mass was dry-mixed with a Henschel mixer manufactured by Mitsui Mining Co., Ltd. to obtain toner (1) of the present invention which is a non-magnetic one-component developer.

The weight average particle diameter and the average circularity of the toner (1) were calculated by using a flow type particle image measuring apparatus manufactured by Toago Medical Electronics Co., Ltd., and they were 7.0 μm and 0.9, respectively.
It was 79.

Using toner (1) and the image forming apparatus as shown in FIG. 9, under high humidity conditions (temperature 22 ° C., humidity 85% R
H), continuous 3000 sheets are printed, and the first sheet, 5
Image evaluation was performed using the 0th and 3000th images. The image forming apparatus will be described below.

FIG. 9 is a schematic view of a modified 1200 dpi laser beam printer (“LBP-840” manufactured by Canon Inc.) which utilizes an electrophotographic process of a non-magnetic one-component contact developing system. In this example, an apparatus obtained by modifying the following parts (a) to (h) was used. In addition, the reference numerals in FIG.
~ The same as Fig. 8. (A) Change the process speed to 65 mm / s. (B) The charging method of the apparatus was direct charging by contacting a rubber roller, and the applied voltage was a DC component (-1200V). (C) Medium resistance rubber roller (diameter 16 mm, hardness ASKER-C 45 degrees, resistance 1) made of silicone rubber in which carbon black is dispersed in the toner carrier (developing sleeve) 2.
0 ⁵ Ω · cm) and abutted on the photoconductor drum 1. (D) The rotational peripheral speed of the toner bearing member was in the same direction at the contact portion with the photosensitive drum 1, and was driven so as to be 150% of the rotational peripheral speed of the photosensitive drum 1. (E) The photoconductor was changed to the following.

As the photosensitive drum 1 used here, Al
A cylinder was used as a base body, and layers having the following constitution were sequentially laminated by dip coating to prepare a photosensitive drum. (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 20000 by Ostwald viscosity method) at a weight ratio of 8:10. Film thickness 20 μm. (F) As a means for applying toner to the toner carrier, an application roller 9 made of urethane foam rubber is provided in the developing device 7 and brought into contact with the toner carrier. A voltage of about −550V is applied to the coating roller 9. (G) A resin-coated stainless steel blade (elasticity regulating blade 3) was used to control the coating layer of the toner on the toner carrier. (H) The applied voltage at the time of development was only the DC component (-450V).

A commercially available paint was applied very thinly on the surface of a rubber roller having the same diameter, the same hardness and the same resistance as the toner carrier used in the image forming apparatus, and after temporarily assembling the image forming apparatus, the rubber roller was removed, The NE length was measured by observing the surface of the stainless steel blade with an optical microscope. The NE length was 1.31 mm.

The electrophotographic 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 charger (only DC is applied) and uses the photosensitive drum 1 which is an electrostatic latent image carrier.
To be uniformly charged. After charging, an electrostatic latent image is formed by exposing the image portion with a laser beam 22 to form a visible image with toner, and then the toner image is transferred to the transfer material 15 by the roller 16 to which a voltage of +700 V is applied. To have.

Regarding the charging potential of the photosensitive drum 1, the dark portion potential was -580V and the light portion potential was -150V.

The gradation curve was obtained by the following method.

The gradation teaching is 64 gradations, and the dither method (fat
The number of gradations is appropriately changed by
Use the image output in dpi, measure the image density,
The tone curve was determined. The image density was measured using a Macbeth densitometer (manufactured by Macbeth Co.).

As the evaluation image, a photographic image having a well-balanced blend of images from the low-density portion to the high-density portion was used.

Regarding the evaluation of the gradation of the highlight part,
It is defined as follows. ⊚: Very excellent in gradation. ◯: The gradation is excellent. Δ: Gradation is slightly inferior. X: Poor gradation.

The reproducibility of the intermediate density portion was determined as follows. A: Reproduced very preferably. ◯: Reproduced preferably. Δ: There is a problem in reproducibility. X: There is a problem in reproducibility.

Regarding the image density, a Macbeth densitometer (manufactured by Macbeth Co.) was used, and the measured value at the place where the image density was the largest was taken as the total solid image density.

Table 2 shows various physical properties of the toner and the image forming apparatus.
And the evaluation results are shown in Table 3. In addition, "P.
Y. "Is pigment yellow, and" SY "is solvent yellow.

(Example 2) Styrene, acrylic acid-n-
Styrene-acrylic resin obtained by polymerizing butyl and divinylbenzene (Mn: 21000, Mw: 9600
0, Tg: 66 ° C.) to 100 parts by mass of C.I. I. Pigment Yellow 180 3 parts by mass C.I. I. Solvent Yellow 162 3 parts by mass Metallic salicylate compound 2.8 parts by mass Ester wax (endothermic peak = 66 ° C.) 10.8 parts by mass were added, melt-kneaded with a twin-screw extruder, and pulverized to obtain a yellow pulverized product. .

This pulverized product was subjected to a spherical treatment by modifying the toner composition by thermal and mechanical shearing forces in a surface modifying machine.

100 parts by mass of the pulverized product of the spheronized toner composition was added to an aqueous medium consisting of 950 parts by mass of ion-exchanged water (heat-retained at 60 ° C.) dispersant: calcium phosphate (32 parts by mass) to prevent precipitation. Stirring was performed with a paddle stirring blade so that a moderate flow rate was applied. afterwards,
3.0 parts by mass of potassium persulfate was dissolved in 3 parts by mass of styrene monomer kept at 60 ° C. and added to the above suspension system.

While maintaining the water temperature at 60 ° C., the mixture was stirred for 7 hours with a paddle stirring blade, and then hydrochloric acid was added to dissolve the dispersant.
After that, filtration, washing with ion-exchanged water, and drying,
The obtained particles were classified by a multistage classifier to obtain toner particles (2).

100 parts by mass of the toner particles (2) were treated with hexamethyldisilazane in the same manner as in Example 1 to prepare a hydrophobic silica fine powder (BET: 300 m ² / g) of 1.
Two parts by mass were dry-mixed with a Henschel mixer to obtain a toner (2) of the present invention which is a non-magnetic one-component developer. The weight average particle diameter and the average circularity of the toner (2) were 7.1 μm and 0.966, respectively.

Using toner (2) and the same image forming apparatus as in Example 1, evaluation was performed in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

Example 3 Styrene used in Example 2
C. to 100 parts by weight of acrylic resin. I. Pigment Yellow 151 3 parts by mass C.I. I. Solvent Yellow 162 2.5 parts by mass Metal salicylate compound 2.8 parts by mass Ester wax (endothermic peak: 66 ° C.) 10.8 parts by mass are added, melt-kneaded with a twin-screw extruder, and crushed to obtain a yellow crushed product. Obtained.

The pulverized product was subjected to thermal and mechanical shearing forces in a surface modifying machine to modify the toner composition and subjected to spheroidizing treatment. The spheroidized toner composition was classified by a multistage classifier to obtain toner particles (3).

100 parts by mass of the toner particles (3) were treated with hexamethyldisilazane in the same manner as in Example 1 to prepare a hydrophobic silica fine powder (BET: 300 m ² / g) of 1.
Two parts by mass were dry-mixed with a Henschel mixer to obtain a toner (3) of the present invention which is a non-magnetic one-component developer. The weight average particle diameter and the average circularity of Toner (3) were 6.8 μm and 0.929, respectively.

Using toner (3) and the same image forming apparatus as in Example 1, evaluation was performed in the same manner as in Example 1. Table 3 shows various physical properties of the toner and the image forming apparatus, and Table 4 shows evaluation results.

(Example 4) The C.I. I. Pigment Yellow 180 3 parts by mass C.I. I. Instead of Solvent Yellow 162 4 parts by mass, C.I. I. Pigment Yellow 120 0.4 parts by mass C.I. I. Toner particles (4) and toner (4), which is a non-magnetic one-component developer, are the same as in Example 1 except that 1.0 part by mass of Solvent Yellow 162 is used.
Got The weight average particle diameter and the average circularity of the toner (4) were 7.0 μm and 0.955, respectively.

The image forming apparatus had the same configuration as that of Example 1 except that a resin-coated phosphor bronze plate blade was used in place of the stainless blade. The NE length of the device
When measured in the same manner as in Example 1, the NE length was 4.00 mm.

Using the toner (4) and the above image forming apparatus,
Evaluation was carried out in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

(Example 5) The C.I. I. Pigment Yellow 180 3 parts by mass C.I. I. Instead of Solvent Yellow 162 4 parts by mass, C.I. I. Pigment Yellow 175 6 parts by mass C.I. I. Toner particles (5) and toner (5) which is a non-magnetic one-component type developer are the same as in Example 1 except that 0.4 part by mass of Solvent Yellow 162 is used.
Got The weight average particle diameter and the average circularity of the toner (5) were calculated to be 7.2 μm and 0.957, respectively.
Met.

In the image forming apparatus, the diameter of the rubber roller, which is the toner carrier, is changed from the diameter of 16 mm to 14 m.
m, and instead of the stainless steel blade, a resin-coated phosphor bronze plate blade was used. Other than the above changes,
The configuration is the same as that of the first embodiment. When the NE length of the apparatus was measured by the same method as in Example 1, the NE length was 0.9.
It was 1 mm.

Using the toner (5) and the above image forming apparatus,
Evaluation was carried out in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

(Example 6) In Example 1, C.I. I.
Toner particles (6) and toner (6) were obtained in the same manner as in Example 1 except that Solvent Yellow 162 was not added. The weight average particle diameter and the average circularity of the toner (6) were 7.0 μm and 0.971, respectively.

In the image forming apparatus, the diameter of the rubber roller, which is the toner carrier, is changed from the diameter of 16 mm to 13 m.
The configuration was the same as in Example 1 except that m was changed. When the NE length was measured by the same method as in Example 1, N
The E length was 0.44 mm.

Using the toner (6) and the above image forming apparatus,
Evaluation was carried out in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

(Comparative Example 1) In Example 1, C.I. I.
Toner particles (7) and toner (7) were obtained in the same manner as in Example 1 except that Pigment Yellow 180 was not added. The weight average particle diameter and the average circularity of the toner (7) were 7.1 μm and 0.969, respectively.
The image forming apparatus had the same configuration as that of Example 1, and the toner (7) was used and evaluated in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

Comparative Example 2 3 parts by mass of C.I. used in Example 1 were used. I. Pigment Yellow 180, instead of C.I. I.
Pigment Yellow 13 was used in the same manner as in Example 1 except that 3 parts by mass of Pigment Yellow 13 was used to obtain Toner Particles (8) and Toner (8). The weight average particle diameter and the average circularity of the toner (8) were 7.0 μm and 0.971, respectively.

In the image forming apparatus, the diameter of the rubber roller, which is the toner carrying member, is changed from 16 mm to 20 mm.
Changed to mm. Further, instead of the stainless steel blade, a copper plate blade having a longer length in the vertical direction was used. Other configurations are the same as those in the first embodiment. When the NE length was measured by the same method as in Example 1, the NE length was 6.30 mm.

Using the toner (8) and the above image forming apparatus,
Evaluation was carried out in the same manner as in Example 1. Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

(Comparative Example 3) The toner (1) used in Example 1 was used.

With respect to the image forming method, the diameter of the rubber roller, which is the toner carrier, is 16 mm and the hardness is 45 degrees, and the diameter is 13 mm and the hardness is 65 degrees.
Further, instead of the stainless steel blade, a phosphor bronze plate blade having a shorter length in the longitudinal direction was used. Other configurations were the same as those in the first embodiment. When the NE length was measured by the same method as in Example 1, the NE length was 0.0
It was 5 mm.

Using the toner (1) and the above image forming apparatus,
The evaluation was performed in the same manner as in Example 1, but the unevenness in density was observed on the entire surface of the obtained image, so the evaluation was stopped.
Table 2 shows various physical properties of the toner and the image forming apparatus, and Table 3 shows evaluation results.

(Embodiment 8) An image forming apparatus using the non-magnetic one-component contact developing system developing apparatus 7 shown in FIG. 3 is used as the developing apparatus 7b of the image forming apparatus shown in FIG. An image was formed using the manufactured toner (1).

The developing device 7 was filled with the toner (1), and the photosensitive drum 1 and the toner carrying member of the developing device 7 were placed in contact with each other to form an image. The NE of the developing device 7
The length was 1.21 mm.

As a result, it was possible to obtain an image in which the gradation property of the highlight part and the density reproducibility of the intermediate density part were excellent and the image density of all the solid parts was also good.

(Embodiment 9) An image forming apparatus using the non-magnetic one-component contact developing type developing apparatus 7 shown in FIG. 3 is used as the developing apparatus 7a of the image forming apparatus shown in FIG. An image was formed using the manufactured toner (1).

The developing device 7 was filled with the toner (1), and the photosensitive drum 1a and the toner carrier of the developing device 7 were placed in contact with each other to form an image. The N of the developing device 7
E length is. It was 20 mm.

As a result, it was possible to obtain an image in which the gradation property of the highlight part and the density reproducibility of the intermediate density part were excellent and the image density of all the solid parts was also good.

[0252]

[Table 2]

[0253]

[Table 3]

[0254]

As described above, according to the present invention,
In the non-magnetic one-component system contact development method, a good gradation curve can be obtained continuously, and good image gradation and image density can be obtained even in a high humidity environment. Electrostatic copying machines, laser printers, etc. In, high quality image formation is realized.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a gradation curve in an image forming method according to the present invention.

FIG. 2 is an explanatory diagram of NE length in the image forming method of the present invention.

FIG. 3 is a schematic configuration diagram of an example of an apparatus for performing the image forming method of the present invention.

FIG. 4 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.

FIG. 5 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.

FIG. 6 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.

FIG. 7 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.

FIG. 8 is a schematic configuration diagram of another example of an apparatus for carrying out the image forming method of the present invention.

FIG. 9 is a schematic configuration diagram of an image forming apparatus used in an embodiment of the present invention.

[Explanation of symbols]

1, 1a to 1d Photosensitive drum 2 Development sleeve 3 Elasticity regulation blade 4 toner 5 Toner container 6 Presser plate 7, 7a to 7d Developing device 8 NE length 9 Application roller 10 charging roller 10a conductive elastic layer 10b core metal 11-13 Bias power supply 14 exposure 15 Transfer material 16 Transfer member 17 Pressure roller 18 Heating roller 19, 19a-19d cleaner 21 Light source device 22 Laser light 23 Fixing device 24, 51 Development unit 25 Intermediate transfer drum 25a conductive support 25b elastic layer 26 Bias power supply 27 Transfer material tray 28 Secondary transfer device 30 Intermediate transfer belt 31 Laura 32 Primary transfer roller 33a Secondary transfer opposing roller 33b Secondary transfer roller 34-36 Bias power supply 39 Charging member for cleaning 41a to 41d Image forming unit 42a-42d latent image forming means 43a to 43d Transfer discharging unit 44, 44a to 44d Primary charging unit 45 Static eliminator 46 conveyor belt 48 Adsorption charger 49a to 49d Separating and discharging unit 50 outlet 60 transfer drum 61 gripper 62 Transfer charger 63a, 63b Separation charger 64 Separation guide 71a Photosensitive layer 71b Photoconductive insulating material layer 72 Cleaning means 73 Transfer belt 74 Bias roller 74a core 74b Conductive elastic layer 75 Tension roller 76 bias power supply

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Handa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tatsuya Nakamura             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Koji Inaba             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Katsuyuki Nonaka             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H005 AA06 AA15 AA21 AB06 CA21                       EA07 EA10 FA07                 2H077 AC04 AD02 AD06 AD13 AD16                       AD35 AE04 EA14 EA15

Claims (12)

[Claims] 1. A charging step of externally applying a voltage to a charging member to charge the electrostatic latent image carrier; a latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier; The maximum length from the free end of the toner regulating member to the contacting portion with the surface of the toner bearing member is determined by fixing the toner regulating member fixed so as to abut on the surface of the toner bearing member carrying toner. Toner layer forming step of regulating the toner layer on the toner carrier by bringing the toner regulating member into contact with the surface of the toner carrier so that the NE length) is 0.1 mm or more and less than 5.0 mm; Development step of developing the electrostatic latent image to form a toner image on the electrostatic latent image carrier by bringing the toner layer carried on the surface of the toner into contact with the surface of the electrostatic latent image carrier; toner image Transfer to or from a transfer material with or without an intermediate transfer member A toner used in an image forming method, which comprises at least a fixing step of fixing a toner image on a transfer material, wherein the toner has a toner particle containing at least a binder resin and a colorant. A toner for image formation, wherein the colorant contains at least a pigment having a basic structural formula (1) shown below. [Chemical 1] 2. The toner comprises C.I. I. The image forming toner according to claim 1, which contains at least a dye classified as Solvent Yellow 162. 3. The image forming toner according to claim 1, wherein the total content (A) of the pigment is 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. . 4. The total pigment content (A) is 0.5 to 15 parts by mass and the dye content (B) is 0.5 to 15 parts by mass with respect to 100 parts by mass of the binder resin. Yes and A / B
Is 0.5 to 3, and the image forming toner according to claim 2. 5. The pigment is C.I. I. Pigment Yellow 120, 151, 154, 175, 180, 181 is a benzimidazolone-based colorant, and the image forming toner according to claim 1. 6. The toner has a particle circularity distribution of 0.95 as measured by a flow-type particle image analyzer.
The toner according to any one of claims 1 to 5, which has an average circularity of 0 to 0.998. 7. A charging step of externally applying a voltage to a charging member to charge the electrostatic latent image carrier; a latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier; Toner layer forming step in which the toner layer on the toner carrier is regulated by the toner regulating member; the toner layer carried on the surface of the toner carrier is brought into contact with the surface of the electrostatic latent image carrier to form an electrostatic latent image. A developing step of developing the image to form a toner image on the electrostatic latent image carrier; a transfer step of transferring the toner image to a transfer material with or without an intermediate transfer body; a toner image on the transfer material An image forming method including at least a fixing step of fixing, wherein a maximum length (NE length) from a free end portion of the toner regulating member to a contact portion with the surface of the toner carrier is 0.1 mm or more and 5.0 or more.
The toner is a non-magnetic one-component toner having toner particles containing at least a binder resin and a colorant, and the colorant is a pigment classified into the basic structural formula (1) shown below. An image forming method comprising at least: [Chemical 2] 8. The toner is C.I. I. The image forming method according to claim 7, further comprising at least a dye classified as Solvent Yellow 162. 9. The image forming method according to claim 7, wherein the total content (A) of the pigment is 0.5 to 20 parts by mass with respect to 100 parts by mass of the binder resin. 10. The total content (A) of the pigment is 0.5 to 15 parts by mass and the content (B) of the dye is 0.5 to 15 parts by mass with respect to 100 parts by mass of the binder resin. Yes and A /
The image forming method according to claim 8, wherein B is 0.5 to 3. 11. The pigment is C.I. I. Pigment Yellow 120, 151, 154, 175, 180, 181 is a benzimidazolone-based colorant, and the image forming method according to claim 7. 12. The toner has a circularity distribution of particles measured by a flow particle image analyzer of 0.9.
The image forming method according to any one of claims 7 to 11, which has an average circularity of 50 to 0.998.