JP2002221829A - Image forming method and developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming method which stabilizes image density in spite of continuous printing of multiple sheets at and under a high temperature and high humidity, is excellent in durability and stability without fogging and lessens contamination to an electrostatic charging roller. SOLUTION: The developer is a two-component developer having toners and carriers. The average circularity of the toners in a circle equivalent diameter-circularity scattergram of a number standard measured by a flow type particle image measuring instrument is 0.950 to 0.995. The carriers are magnetic material dispersion type coated carriers. The 50% diameter by the volumetric average of the carriers is 15 to 60 μm and the content of the particles of grain size (2D/3>=) below 2/3 of the 50% particle size is <=5 vol.%. SF-1 thereof is 100 to 130. Electrostatic charging means are the electrostatic charging roller having a conductive elastic layer and the ten point mean surface roughness (Rz) of the electrostatic charging roller is smaller than a circle equivalent number average diameter D1 (μm).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming method and an image forming method for forming and developing an electric latent image in an electrophotographic method or an electrostatic printing method. The present invention relates to an image forming method in which collection of toner is performed by the same means.

[0002]

2. Description of the Related Art Conventionally, many electrophotographic methods are known. Generally, a photoconductive substance is used to form an electrostatic latent image on a photoreceptor by various means, and then the latent image is developed with toner to form a toner image. After transferring the toner image to the transfer material, the toner image is fixed on the transfer material by heat, pressure, heat and pressure, etc. to obtain a copy or print. The toner particles remaining on the photoconductor without being transferred onto the transfer material are removed from the photoconductor by a cleaning process.

[0003] The photoreceptor cleaning process has been conventionally performed by blade cleaning, fur brush cleaning,
Means such as roller cleaning have been used. This means mechanically scrapes off or removes the transfer residual toner on the photoreceptor and collects the transfer residual toner in a waste toner container. Therefore, a problem is likely to occur due to the member constituting such means being pressed against the surface of the photoreceptor. For example, the photosensitive member surface is worn by strongly pressing the cleaning member.

Further, the provision of the cleaning means inevitably increases the size of the entire apparatus, which has been a bottleneck when aiming for a more compact apparatus.

Further, from the viewpoint of ecology, a system free of waste toner is desired.

For example, in Japanese Patent Publication No. 5-69427,
There has been proposed an image forming apparatus that employs a technique called a development / collection method or a cleanerless method. In this image forming apparatus, one image is formed per one rotation of the photoconductor, so that the influence of the transfer residual toner does not appear in the same image. JP-A-64-20587, JP-A-2-259784, JP-A-4-50886, JP-A-5-165
Japanese Patent Publication No. 378 proposes a method in which residual toner is dispersed on a photoreceptor by a dispersing member and non-patterned, so that even if the same surface of the photoreceptor is used a plurality of times for one image, it is difficult for the image to appear on the image. are doing.

[0007] Today, there is a need to transfer toner images to various transfer materials. When a voltage is applied to a member for non-patterning the residual toner, a cleaner-less system is used, but it is difficult to make the entire apparatus compact.

Japanese Patent Application Laid-Open No. 2-51168 proposes to obtain a stable charging characteristic by using a spherical toner and a spherical carrier in a cleanerless electrophotographic printing method. Even if it is satisfactory to some extent, the quality of the image decreases as it is repeatedly used, and it is necessary to improve the durability.

In recent years, there has been a strong demand for high image quality by users, and from this viewpoint, toner having high sphericity is advantageous.
Japanese Patent Application Laid-Open No. 61-279864 discloses a shape factor SF-1.
And SF-2. Further, Japanese Patent Application Laid-Open No. 63-235953 proposes a magnetic toner which is made spherical by a mechanical impact force.
However, the transferability is not sufficient although the improvement in transferability is recognized to some extent, and the developability has not been able to achieve high definition.

Japanese Patent Application Laid-Open No. 9-160283 discloses that the average particle size is 6 to 10 μm and the average circularity is 0.85 μm.
A toner having a content of particles having a circularity of 0.85 or less and having a circularity of 0.85 or less has been proposed. The toner has fluidity, charge rising property, and cleaning property with a cleaning blade. However, high-definition development has not been achieved, and there is no description on cleaner-less development.

In the developing and collecting system, filming is liable to occur on the photoreceptor when used repeatedly. Therefore, in Japanese Patent Application Laid-Open No. 5-61383, the filming is performed by making the surface of the photoreceptor uniform with a homogenizing member. Has been proposed, but further improvements are expected.

In recent years, various organic photoconductive materials have been developed as a photoconductive material for an electrophotographic photoreceptor. In particular, a function-separated type having a charge generation layer and a charge transport layer laminated thereon has been put to practical use. And printers and facsimile machines. As a charging unit in such an electrophotographic apparatus, a unit utilizing corona discharge has been used, but a large amount of ozone is generated.

As a technique for solving such a problem, a charging member such as a roller or a blade is brought into contact with the surface of a photoreceptor to form a narrow space in the vicinity of the contact portion and interpreted according to the so-called Paschen's law. A charging method has been developed in which the generation of ozone is suppressed as much as possible by forming a discharge that can be performed. Among them, a roller charging method using a charging roller as a charging member is particularly preferably used from the viewpoint of charging stability.

Since this charging is performed by discharging from the charging member to the member to be charged, the charging is started by applying a voltage higher than a certain threshold voltage. For example, when a charging roller is brought into contact with a photosensitive member containing an organic photoconductive substance having a photosensitive layer thickness of about 25 μm, the surface potential of the photosensitive member increases when a voltage of about 640 V or more is applied. After that, the photoconductor surface potential linearly increases with a slope of 1 with respect to the applied voltage. Thereafter, this threshold voltage is set to the charging start voltage Vth
Is defined. That is, in order to obtain the photoconductor surface potential Vd, the charging roller needs a DC voltage higher than Vd + Vth. Furthermore, since the resistance value of the charging roller fluctuates due to environmental fluctuations or the like, it has been difficult to set the potential of the photoconductor to a desired value.

For this reason, as disclosed in Japanese Patent Application Laid-Open No. 63-149669, a DC voltage corresponding to a desired Vd has a peak-to-peak voltage of 2 × Vth or more, as disclosed in JP-A-63-149669. A DC + AC charging system in which a voltage on which a voltage is superimposed is applied to a contact charging roller is used. This is for the purpose of the potential leveling effect of the AC, and the potential of the member to be charged converges to Vd, which is the center of the peak of the AC voltage, and is hardly affected by disturbance such as environmental fluctuation.

However, even in such a charging method, the essential charging mechanism uses a discharging phenomenon from the charging member to the photoreceptor, so that the voltage required for charging is as described above. A value higher than the photoconductor surface potential is required. Further, generation of vibration and noise (hereinafter referred to as AC charging noise) of the charging member and the photoconductor due to the electric field of the AC voltage,
And the deterioration of the photoreceptor surface due to discharge becomes remarkable,
It was a new problem.

Japanese Patent Application Laid-Open No. Hei 5-196662 proposes that secondary particles obtained by fusing primary polymerized particles are used for toner. It has been proposed to use a transparent polymerized toner, and Japanese Patent Application Laid-Open No. 5-188637 specifies a volume average diameter, a number average diameter, a charge amount of toner, an area ratio of a toner projected image, a BET specific surface area of toner, and the like. Although the use of toner has been proposed, an excellent image forming method using a developing and collecting system has been desired.

When a technique called a development / collection method or a cleaner-less technique is used, the exposure of the memory on the image is interrupted by the influence of the transfer residual toner, the formation of the electrostatic latent image is disturbed, and a desired potential is obtained. And a negative memory is easily generated on the image. Furthermore, if the transfer residual toner is large, a positive memory is likely to be generated on the image because it cannot be completely collected in the developing process. Using non-patterned members tends to reduce image quality.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method which solves the above-mentioned problems.

That is, an object of the present invention is to provide a cleanerless image forming method.

An object of the present invention is to provide an image forming method of a cleanerless type which is excellent in fog suppression and excellent in durable stability which is the same as the initial state even when a large number of continuous prints are performed in a high temperature and high humidity environment. It is in.

An object of the present invention is to provide a cleaner-less image forming method which does not change the initial state even when a large number of sheets are continuously printed in a high temperature and high humidity environment. is there.

An object of the present invention is to provide a cleaner-less image forming method having good transferability which is the same as the initial one even when a large number of continuous prints are performed in a high temperature and high humidity environment.

It is a further object of the present invention to provide a developer applicable to the above image forming method.

[0025]

According to the present invention, there is provided an image carrier,
Charging means for charging the image carrier surface; information writing means for forming an electrostatic latent image on the charged image carrier; developing means for supplying a developer to the electrostatic latent image to visualize the electrostatic latent image; ,
Using an image forming apparatus having a transfer unit that transfers the visualized developer image to a transfer material, and a developer charge amount control unit that is located upstream of the charging unit and charges the developer on the surface of the image carrier. In the image forming method of forming an image by a developing and collecting method, the developer remaining on the image carrier after the transfer process is charged to a normal polarity by the developer charge amount control unit, and the charging unit is charged. When the surface of the image bearing member is charged with a proper charge amount, the developer is a two-component developer having a toner and a carrier containing at least a binder resin and a colorant, and a flow type particle image of the toner. An average circularity in a number-based circle equivalent diameter-circularity scattergram measured by a measuring device of 0.950 to 0.995, and the carrier is a magnetic material-dispersed coated carrier; 50% diameter 15 to 60μm due to volume-average, less than 2/3 of the particle diameter of the 50% particle size (2D / 3
≧) 5% by volume or less, SF-1 is 100%
To 130, the charging means for charging the surface of the image carrier is a charging roller having a conductive elastic layer, and the number-based circle equivalent diameter measured by a flow-type particle image measuring device−
Circle equivalent number average diameter D ₁ in circularity scattergram
(Μm) than the 10-point average surface roughness (R
and z) is small.

The present invention also provides an image carrier, charging means for charging the surface of the image carrier, information writing means for forming an electrostatic latent image on the charged image carrier, and developing the electrostatic latent image. Developing means for supplying an agent to visualize the electrostatic latent image, transfer means for transferring the visualized developer image to a transfer material, and charging the developer on the surface of the image carrier which is located upstream of the charging means. An image forming method for forming an image using a developing and collecting method using an image forming apparatus having a developer charge amount controlling means, wherein the developer remaining on the image carrier after the transfer step is formed by the above-described method. When a developer is charged to a normal polarity by a developer charge amount control unit and the image bearing member surface is charged by the charging unit, at least the developer is used in an image forming method for setting an appropriate charge amount. Toner and carrier containing coloring resin and colorant A two-component developer having an average circularity of 0.950 to 0.995 in a number-based circle equivalent diameter-circularity scattergram of the toner measured by a flow type particle image measuring apparatus of 0.950 to 0.995; Is a magnetic material-dispersed coated carrier having a 50% diameter by volume average of 15 to 60 μm, 50%
The content of particles having a particle size of 2/3 or less (2D / 3 ≧) is 5% by volume or less, SF-1 is 100 to 130,
The charging means for charging the surface of the image carrier is a charging roller having a conductive elastic layer, and the circle-equivalent diameter based on the number-based circle equivalent diameter-circularity scattergram measured by a flow-type particle image measuring device. The present invention relates to a developer characterized in that the charging roller has a 10-point average surface roughness (Rz) smaller than D ₁ (μm).

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of a cleanerless image forming method using a developing and collecting method will be described. The principle is to control the charge polarity and charge amount of the toner on the photoreceptor in each step of electrophotography and to use a reversal development method.

When a negatively charged photosensitive member and a negatively charged toner are used, in the transfer step, an image visualized by a positive polarity transfer member is transferred to a transfer material. Depending on the relationship between the type of transfer material (difference in thickness, resistance, dielectric constant, etc.) and the image area, the charge polarity of the transfer residual toner varies from plus to minus. However, due to the negative polarity charging member when charging the negatively charged photoreceptor, even if the surface of the photoreceptor and the untransferred toner become positive in the transfer process, the charging polarity is uniformly negative. Can be aligned. therefore,
When reversal development is used as the developing method, the negatively charged transfer residual toner remains on the light potential portion to be developed, and the dark portion potential not to be developed has toner carrying due to the development electric field. The transfer residual toner is attracted to the body, and no toner remains on the dark potential portion.

This will be described more specifically with reference to FIG.

The electrostatic latent image on the negatively charged photosensitive member 102 is reversibly developed by a negatively charged toner with a developer having a toner and a carrier carried on a toner carrier (developing roller) 101. As a result, a toner image is obtained. The toner image on the photoconductor is transferred to a transfer material 104 by a corona transfer charger 103 to which a positive bias is applied. The toner that cannot be completely transferred to the transfer material remains on the photosensitive member 102 as transfer residual toner.

The transfer residual toner includes toner particles that have been positively polarized by receiving a positively biased transfer bias. When the transfer residual toner charges the surface of the photoconductor 102 to the negative polarity by the corona charger 105, the toner particles having the positive polarity are converted to the negative polarity.

Accordingly, the toner on the photoconductor 2 that has passed through the corona charger 105 has a uniform negative polarity, and the photoconductor surface potential also has a negative polarity.

Next, an electrostatic latent image is formed by image exposure 106, and the electrostatic latent image on the photosensitive member 102 is developed by the developing roller 101 carrying toner. In the reversal development, an image exposure portion (bright portion potential portion) is developed.
Is applied between the non-exposed portion of the photoreceptor and the potential of the exposed portion, so that the electrostatic force attracting the toner to the toner side is applied to the negative polarity toner existing on the non-exposed portion (dark portion potential portion). It can be operated to collect the toner remaining after the transfer.

Although a force remaining on the surface of the photoreceptor acts on the negative polarity toner existing on the exposed portion, it is a portion where a toner image is originally formed, and no problem occurs.

In FIG. 2, the charging roller 31 is used as a means for charging the surface of the photosensitive member 36 to a negative polarity, and the transfer roller 37 to which a positive bias is applied is used as the transfer charging means.

As described above, by controlling the charge polarity of the transfer residual toner, the cleaner-less image forming method using the developing / collecting method can be carried out. It cannot be completely recovered, and further improvement is desired.

On the other hand, the present inventors have made intensive studies and as a result, in a cleaner-less system using the developing and collecting method, the image forming method is located upstream of the charging means for charging the surface of the photosensitive member, and is located on the surface of the photosensitive member. And a toner charge amount control means for charging the toner of the image forming apparatus, wherein the toner remaining on the photoreceptor after the transfer process is charged to the normal polarity by the toner charge amount control means using an image forming apparatus. The average circularity of the toner is 0.950 to 0.995, and the 50% diameter by volume average of the magnetic substance-dispersed carrier is 15 to 6%.
0 μm, particle size of 2/3 or less of 50% particle size (2D / 3 ≧)
Wherein the content of the particles is 5% by volume or less, SF-1 is 100 to 130, and the charging means for charging the photoreceptor surface is a charging roller having a conductive elastic layer. Number-based circle equivalent diameter to be measured-circle equivalent number average diameter D ₁ (μm) in the circularity scattergram
It has been found that the above problem in the developing and collecting system is solved when the 10-point average surface roughness (Rz) of the charging roller is smaller than that of the charging roller.

The details will be described below.

In the toner having an average circularity of the present invention,
Since the external additive uniformly adheres to the toner surface, high transfer efficiency is produced, and transfer residual toner is hardly generated. However, as the durability increases, the embedding of the external additive into the toner surface is faster than that of the irregular-shaped toner, so that it is difficult to maintain high transfer and fog on the transfer material increases.

On the other hand, problems such as image defects due to charge leakage due to low carrier specific resistance of iron powder carriers and ferrite carriers, and image defects due to toner packing in a developing machine due to large saturation magnetization are encountered. The magnetic material-dispersed resin carrier proposed to solve this problem can be designed with higher specific resistance, lower saturation magnetization and smaller true specific gravity than iron powder carrier and ferrite carrier, so that light load development can be easily performed. Thus, damage to the toner in the developing machine can be suppressed, and embedding of the external additive into the toner surface due to durability can be greatly reduced.

Further, since the particles can be easily designed into a spherical shape having a small shape distortion and a high particle strength, the particles have excellent fluidity, and can provide a more uniform charge. A stable image density can be maintained by combination with the toner.

However, in a cleanerless image forming method using a charging roller for charging the toner to a normal polarity by the toner charge amount controlling means, an image having poor transferability due to deformation of the toner under a high temperature and high humidity environment. It was not enough yet. In other words, this is because the toner adheres slightly to the charging roller due to continuous continuous paper running with durability, the toner is damaged, and the deformed shape is collected in the developing machine by developing and collecting, and further formed by the stirring blade etc. After the deformation, the toner aggregates are formed and are developed at the time of reversal development, and are transferred with the regular toner in the transfer section, so that a poor transfer image is formed.

On the other hand, the present inventors have made intensive studies and found that in the above-described image forming method, the average surface roughness (R) of the charging roller is larger than the average circle equivalent number diameter D ₁ (μm) of the toner.
By reducing z), it is possible to prevent the transfer residual toner, whose transferability has been reduced due to durability, from adhering (fixing) to the surface of the charging roller and the surface of the drum, and furthermore, to the nip portion between the charging roller and the photosensitive drum. In this case, the image damage caused by the contamination of the charging roller and the transfer failure image caused by the contamination were successfully reduced by reducing the toner damage caused by the toner.

Hereinafter, an image forming apparatus (image recording apparatus) according to the present invention will be described.

FIG. 3 is a schematic structural diagram of an example of an image forming apparatus according to the present invention. The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process, a contact charging type, a reversal developing type, a cleaner-less type, and an A3 size maximum sheet passing size.

(1) Overall Schematic Configuration of Printer a) Photosensitive Drum 1 is a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum). The photosensitive drum 1 has a subbing layer 1b on the surface of an aluminum cylinder (conductive drum base) 1a, which suppresses light interference and improves the adhesiveness of the upper layer, as shown in the schematic diagram of the layer structure in FIG. The photo charge generation layer 1c and the charge transport layer 1d are formed by applying three layers sequentially from the bottom.

The photosensitive drum of the present invention is not limited to the above. Hereinafter, a typical configuration of the electrophotographic photosensitive member will be described with reference to FIGS. 5, 6, and 7. FIG.

The photosensitive layer comprises an organic photoconductor as a main component. As the organic photoconductor, an organic photoconductive polymer such as polyvinyl carbazole or a low molecular weight organic photoconductive substance is used. And those contained in the resin.

The electrophotographic photosensitive member shown in FIG.
6, a photosensitive layer 17 is provided.
Is a laminated structure of the charge generation layer 19 and the charge transport layer 20 in which the charge generation material 18 is dispersed and contained in the binder resin. In this case, the charge transport layer 20 is laminated on the charge generation layer 19.

In the electrophotographic photosensitive member of FIG. 6, the charge transport layer 20 is laminated below the charge generation layer 19, unlike the case of FIG. In this case, the charge generation layer 19 may contain a charge transport material.

The electrophotographic photosensitive member shown in FIG.
6, a photosensitive layer 17 is provided. The photosensitive layer 17 contains a charge generation material 18 and a charge transport material (not shown) in a binder resin.

Of these, as shown in FIG. 5, a photoreceptor having a structure in which the charge generation layer 19 and then the charge transport layer 20 are laminated in this order from the conductive support 16 side is preferred in the present invention.

As the conductive support 16, a metal such as aluminum or stainless steel, a cylindrical cylinder such as paper or plastic, a sheet or a film, or the like is used. Further, these cylindrical cylinders, sheets or films may have a conductive polymer layer or a resin layer containing conductive particles such as tin oxide, titanium oxide and silver particles as necessary.

An undercoat layer (adhesive layer) having a barrier function and an undercoat function can be provided between the conductive support 16 and the photosensitive layer 17.

The undercoat layer is used for improving the adhesion of the photosensitive layer, improving the coating property, protecting the support, covering defects of the support, improving the charge injection property from the support, protecting the photosensitive layer against electrical breakdown, and the like. Formed for Its film thickness is about 0.2 to 2 μm.

Examples of the charge-generating substance include a beryllium, a thiopiolylium dye, a phthalocyanine pigment, an anthrone pigment, a dibenzavirene quinone pigment, a pyratron pigment, an azo pigment, an indigo pigment, a quinacridone pigment,
Asymmetric quinocyanines, quinocyanines and the like can be used.

As the charge transport material, hydrazone compounds, pyrazoline compounds, styryl compounds, oxazole compounds, thiazole compounds, triarylmethane compounds, polyarylalkane compounds and the like can be used.

The charge-generating layer 19 is prepared by adding the above-described charge-generating substance together with a binder resin and a solvent in an amount of 0.5 to 4 times by a homogenizer, ultrasonic wave, ball mill, vibrating ball mill, sand mill, attritor, roll mill or the like. It is well dispersed, coated and dried. Its thickness is 5μm
Hereinafter, the range of 0.01 to 1 μm is particularly preferable.

The charge transporting layer 20 is generally formed by dissolving the above-described charge transporting substance and a binder resin in a solvent and applying the solution.
The mixing ratio of the charge transport material and the binder resin is 2: 1 to 1: 2.
It is about. Examples of the solvent include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, and chlorinated hydrocarbons such as chlorobenzene, chloroform and carbon tetrachloride. Is used. When this solution is applied, for example, a coating method such as a dip coating method, a spray coating method, or a spinner coating method can be used, and drying is performed at a temperature in the range of 10 to 200 ° C, preferably 20 to 150 ° C. Minutes to 5 hours,
Preferably, it can be carried out under blast drying or still drying for 10 minutes to 2 hours. The thickness of the generated charge transport layer is 5 to 5.
A range of 30 μm, especially 10 to 25 μm is preferable.

The binder resin used for forming the charge generation layer 19 and the charge transport layer 20 includes acrylic resin, styrene resin, polyester, polycarbonate resin, polyarylate, polysulfone, polyphenylene oxide, epoxy resin, polyurethane resin Alkyd resins, unsaturated resins and the like. Particularly preferred resins include polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, polycarbonate resin and diallyl phthalate resin.

The charge generation layer or the charge transport layer may contain various additives such as an antioxidant, an ultraviolet absorber, and a lubricant.

B) The charging means 2 is a contact charging device (contact charging device) as a charging device for uniformly charging the peripheral surface of the photosensitive drum 1, and in this example, a charging roller (roller charging device).

The charging roller 2 holds both ends of the cored bar 2a rotatably by bearing members (not shown), and urges the pressing roller 2e in the direction of the photosensitive drum 1 with respect to the surface of the photosensitive drum 1. The photosensitive drum 1 is brought into pressure contact with a predetermined pressing force, and rotates following the rotation of the photosensitive drum 1. The pressure contact portion between the photosensitive drum 1 and the charging roller 2 is a charging portion (charging nip portion) a.

The peripheral surface of the rotary photosensitive drum 1 is contact-charged to a predetermined polarity and potential by applying a charging bias voltage under predetermined conditions from the power supply S1 to the core 2a of the charging roller 2. In this example, the charging bias voltage for the charging roller 2 is a DC voltage (Vdc) and an AC voltage (Va).
c) is an oscillating voltage superimposed on

DC voltage; -500 V AC voltage; frequency f1000 Hz, peak-to-peak voltage Vpp
1400 V, a vibration voltage in which a sine wave is superimposed, and the peripheral surface of the photosensitive drum 1 is uniformly contact-charged to -500 V (dark potential Vd).

The longitudinal length of the charging roller 2 is 320 mm, and as shown in the schematic diagram of the layer structure in FIG.
It has a three-layer structure in which an elastic layer 2b, a resistance control layer 2c, and a surface layer 2d are sequentially laminated from the bottom around the outer periphery of a. The elastic layer 2b is a foamed sponge layer for reducing charging noise,
The resistance control layer 2c is a conductive layer for obtaining uniform resistance as a whole of the charging roller, and the surface layer 2d is provided to prevent a leak from occurring even if there is a defect such as a pinhole on the photosensitive drum 1. Protective layer.

The 10-point average surface roughness (Rz, JIS-B0601) of the charging member surface of the present invention is preferably 7 μm or less. Preferably it is 5 μm or less. More preferably, it is 3 μm or less. If the above range is exceeded, the discharge amount increases, and erodes the photoreceptor that is the charged body,
So-called scraping of the photoconductor is promoted, and the life of the photoconductor may be shortened.

This will be described in more detail.

In FIG. 4, 2 is a charging member, 2a is a conductive support, 2b is an elastic layer, 2c is a resistance control layer, and 2d is a surface layer. The charging roller may have a configuration of the elastic layer 2b without the resistance control layer 2c and the surface layer 2d.

The conductive support 2a used in the present invention comprises:
Metals such as iron, copper, stainless steel, aluminum and nickel can be used. Further, these metal surfaces may be subjected to plating treatment for the purpose of rust prevention and imparting scratch resistance, but it is necessary that the conductivity is not impaired.

In the charging roller 2, the elastic layer 2b has
Appropriate elasticity is provided to ensure good uniform adhesion of the charging roller 2 to the photoconductor 1.

The conductivity of the elastic layer 2b is adjusted by adding conductive particles such as carbon black or conductive agents such as alkali metal salts and ammonium salts to an elastic material such as rubber. The elasticity is adjusted by adding a process oil and a plasticizer. Specific elastic materials of the elastic layer 2b include, for example, natural rubber, ethylene propylene diene methylene rubber (EPDM), styrene-butadiene rubber (S
BR), synthetic rubbers such as silicone rubber, urethane rubber, epichlorohydrin rubber, isoprene rubber (IR), butadiene rubber (BR), nitrile-butadiene rubber (NBR) and chloroprene rubber (CR), furthermore, polyamide resin, polyurethane resin, Resins such as silicone resins and fluororesins are also included. Further, a foam of the above-described elastic material may be used for the elastic layer 2b.

The electric resistance of the elastic layer is 1 × 10 ³ to 1
It is preferable to have conductivity in the range of × 10 ¹⁰ [Ωcm]. Further, the thickness is not particularly limited because it depends on the diameter of the conductive support.

The surface layer 2d is often provided to prevent bleed-out of the plasticizer and the like in the elastic layer 2b to the surface of the charging roller and to maintain the smoothness and smoothness of the surface of the charging roller. The surface layer 2d is provided by coating or coating a tube.

When the surface layer 2d is provided by coating, specific materials include resins such as polyamide resin, polyurethane resin, acrylic resin, fluorine resin and silicone resin, and further include epichlorohydrin rubber, urethane rubber, and the like.
Examples include chloroprene rubber and acrylonitrile rubber. As a coating method, a dip coating method, a roll coating method, a spray coating method, or the like is preferable.

When the surface layer 2d is provided by covering a tube, specific materials include nylon 12, PFA (ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer resin), and PVDF (polyvinylidene fluoride). , FEP (tetrafluoroethylene-6-fluoropropylene copolymer resin), and thermoplastic elastomers such as polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyester, and polyamide.

The tube may be a heat-shrinkable tube or a non-heat-shrinkable tube. Surface layer 2d
Conductive particles such as carbon black and carbon graphite, and conductive agents such as conductive metal oxides such as conductive titanium oxide, conductive zinc oxide and conductive tin oxide. Used.

The electric resistance of the surface layer is 1 × 10 ⁶ to 1
It is preferably in the range of × 10 ¹⁴ [Ωcm]. Further, the thickness is preferably 2 to 500 μm.
More preferably, it is 2 to 250 μm.

The resistance control layer 2c is often provided to control the resistance of the charging member. Specific examples of the material for the resistance control layer 2c include resins such as polyamide resin, polyurethane resin, fluorine resin, and silicone resin, and further include epichlorohydrin rubber, urethane rubber, chloroprene rubber, and acrylonitrile rubber. Resistance control layer 2c
Also for the purpose of resistance adjustment, conductive particles such as carbon black and carbon graphite, conductive metal oxides such as conductive titanium oxide, conductive zinc oxide and conductive tin oxide, or alkali metal salts and ammonium salts. Can be dispersed.

The resistance control layer 2c is also provided by coating or coating a tube.

The electric resistance of the resistance control layer is 1 × 10 ⁶
It is preferably in the range of ~1 × ¹⁰ 10 [Ωcm].
Further, the thickness is preferably 10 to 1000 μm. More preferably, it is 10 to 750 μm.

The measurement of the volume resistivity in the present invention is performed according to JI
This was performed according to S K 6911.

In FIG. 4, reference numeral 2f denotes a charging roller cleaning member, which in this embodiment is a flexible cleaning film. The cleaning film 2f is disposed in parallel with the longitudinal direction of the charging roller 2 and has one end fixed to a supporting member 2g that reciprocates by a fixed amount in the longitudinal direction. It is arranged to form a contact nip. The support member 2g is driven in a reciprocating motion by a predetermined amount in the longitudinal direction via a gear train by a drive motor of the printer, so that the charging roller surface layer 2
d is rubbed with the cleaning film 2f. As a result, contaminants adhering to the charging roller surface layer 2d (fine powder toner, external additives, etc.) are removed.

C) Information Writing Unit As the information writing unit 3 for forming an electrostatic latent image on the surface of the charged photosensitive drum 1, a method using an LED array, a method using a semiconductor laser, and a liquid crystal shutter array are used. There are methods. This example is a laser beam scanner using a semiconductor laser.

A laser beam modulated in accordance with an image signal sent from a host device such as an image reading device to the printer side is output to scan the uniformly charged surface of the rotary photosensitive drum 1 at the exposure position b. Exposure L (image exposure) is performed. By this laser scanning exposure L, the potential of the surface of the photosensitive drum 1 irradiated with the laser beam decreases, so that an electrostatic latent image corresponding to the scanned and exposed image information is sequentially formed on the rotating photosensitive drum 1 surface. Will be done.

D) Developing means 4 is a developing device (developing device) as developing means for supplying a developer (toner) to the electrostatic latent image on the photosensitive drum 1 to visualize the electrostatic latent image. This is a two-component magnetic brush developing type reversal developing device.

Reference numeral 4a denotes a developing container, and 4b denotes a non-magnetic developing sleeve. The developing sleeve 4b is rotatably disposed in the developing container 4a by exposing a part of its outer peripheral surface to the outside. Reference numeral 4c denotes a non-rotating fixed magnet roller inserted in the developing sleeve 4b, 4d denotes a developer coating blade, 4e denotes a two-component developer contained in the developing container 4a, and 4f denotes a bottom side in the developing container 4a. The provided developer agitating member, 4g, is a toner hopper, which stores toner for replenishment.

Thus, the surface of the rotating developing sleeve 4b is coated as a thin layer, and the toner in the developer conveyed to the developing section c is converted into an electrostatic latent image on the surface of the photosensitive drum 1 by the electric field generated by the developing bias. The electrostatic latent image is developed as a toner image by correspondingly selectively attaching. In the case of this example, the toner adheres to the light-exposed portion on the surface of the photosensitive drum 1 and the electrostatic latent image is reversely developed.

The developer thin layer on the developing sleeve 4b that has passed the developing section c is returned to the developer reservoir in the developing container 4a with the subsequent rotation of the developing sleeve.

In order to maintain the toner concentration of the two-component developer 4e in the developing container 4a within a predetermined substantially constant range, the toner concentration of the two-component developer 4e in the developing container 4a is, for example, an optical toner (not shown). The toner is detected by the density sensor, and the toner hopper 4g is driven and controlled in accordance with the detection information, and the toner in the toner hopper is supplied to the two-component developer 4e in the developing container 4a. The toner supplied to the two-component developer 4e is stirred by the stirring member 4f.

E) Transfer means / fixing means 5 is a transfer device, and in this example, a transfer roller. The transfer roller 5 is pressed against the photosensitive drum 1 with a predetermined pressing force, and the pressing nip portion is a transfer portion d. A transfer material (transfer member, recording material) P is fed to the transfer portion d from a paper feed mechanism (not shown) at a predetermined control timing.

The transfer material P fed to the transfer section d is conveyed while being sandwiched between the rotating photosensitive drum 1 and the transfer roller 5, during which the transfer roller 5 has the normal charging polarity of the toner from the power source S 3. When a positive transfer bias (+2 kV in this example) having a polarity opposite to the negative polarity is applied, the photosensitive drum 1 is placed on the surface of the transfer material P nipping and transferring the transfer portion d.
The toner image on the surface side is sequentially electrostatically transferred.

The transfer material P to which the toner image has been transferred through the transfer section d is sequentially separated from the surface of the rotating photosensitive drum 1 and is conveyed to a fixing device 6 (for example, a heat roller fixing device) to fix the toner image. Image processing (print,
Output).

(2) Cleanerless System and Control of Toner Charge Amount The printer of this embodiment is cleanerless, and is dedicated to removing transfer residual toner slightly remaining on the surface of the photosensitive drum 1 after the transfer of the toner image onto the transfer material P. No cleaning device is provided. The untransferred toner on the surface of the photosensitive drum 1 after the transfer is carried to the developing unit c through the charging unit a and the exposing unit b with the subsequent rotation of the photosensitive drum 1, and is collected by the developing device 4 for both development and use. (Cleanerless system).

In the present embodiment, the developing sleeve 4b of the developing device 4 is rotated in the developing section c in the opposite direction to the traveling direction of the surface of the photosensitive drum 1 as described above. This is advantageous for collecting residual toner.

Since the transfer residual toner on the surface of the photosensitive drum 1 passes through the exposure section b, the exposure process is performed on the transfer residual toner. However, since the amount of the transfer residual toner is small, no significant effect appears.

However, as described above, the transfer residual toner has a charge polarity of a normal polarity, a toner of a reverse polarity (reverse toner),
There is a mixture of toners having a small charge amount, and the reversal toner or the toner having a small charge amount adheres to the charging roller 2 when passing through the charging section a. Failure will occur.

In order for the developing device 3 to effectively carry out development and collection of the transfer residual toner on the surface of the photosensitive drum 1, the charge polarity of the transfer residual toner on the photosensitive drum carried to the developing section c is changed. It is necessary that the toner has a normal polarity and the charge amount is a charge amount of the toner that can develop the electrostatic latent image on the photosensitive drum by the developing device. Inverted toner and toner with an inappropriate charge amount cannot be removed and collected from the photosensitive drum to the developing device, which causes a defective image.

Therefore, in this embodiment, at the position downstream of the transfer section d in the photosensitive drum rotation direction and upstream of the charging section a in the photosensitive drum rotation direction, the charge polarity of the transfer residual toner is set to the negative polarity. There is provided a toner (developer) charge amount control means 7 for uniformity of the toner.

By setting the charging polarity of the transfer residual toner to the negative polarity, which is the normal polarity, when the charging section a located further downstream charges the surface of the photosensitive drum 1 from above the transfer residual toner, The reflection power on the photosensitive drum 1 is increased,
This prevents the transfer residual toner from adhering to the charging roller 2.

Next, the recovery of the transfer residual toner in the developing step will be described.

As described above, the developing device 4 is of a cleaner-less type which is used for both development and cleaning to remove transfer residual toner.

The toner charge amount for the transfer residual toner on the photosensitive drum 1 to be collected by the developing device 4 is an absolute value smaller than the absolute value of the charge amount when the developer is charged by the developer charge amount control means. Is required. This is a so-called charge elimination. If the charge amount of the transfer residual toner is high, the affinity with the drum is superior, the toner is not collected by the developing device 4, and an image defect occurs.

However, as described above, in order to prevent the toner from adhering to the charging roller 2, it is necessary to collect the transfer residual toner charged to a large negative polarity by the toner charge amount control means 7 in the developing device 4. , It is necessary to remove static electricity. The static elimination is performed in the charging section a. That is,
The charging roller 2 has a frequency of 1000 Hz and 140
By applying the AC voltage of 0 V, the transfer residual toner is subjected to AC static elimination. Further, by adjusting the AC voltage applied to the charging roller 2, the toner charge amount after passing through the charging section a can be adjusted by AC static elimination. In the developing step, the transfer residual toner on the photosensitive drum 1 on which the toner should not be developed is collected by the developing device 4 for the above-described reason.

Thus, the tribo of the untransferred toner on the photosensitive drum 1 carried from the transfer section d to the charging section a is charged by the toner charge amount control means 7 so as to have a normal polarity of negative polarity, and is subjected to a charging process. While the toner is prevented from adhering to the charging roller 2, the photosensitive drum 1 is charged to a predetermined potential by the charging roller 2, and at the same time, the transfer performed by the toner charge amount control means 7 to the negative polarity which is the normal polarity. By controlling the charge amount of the residual toner to an appropriate charge amount at which the developing device 4 can develop the electrostatic latent image on the photosensitive drum, the transfer residual toner can be efficiently collected in the developing device. In addition, it is possible to provide an image forming apparatus which is free from a charging failure and a defective image, and which makes use of the advantages of a cleanerless system.

Next, the toner of the present invention will be described.

The method for producing the toner of the present invention is not particularly limited as long as it has the above-mentioned circularity range.

The binder resin for the toner used in producing the toner of the present invention by the pulverization method includes polystyrene;
Styrene-substituted homopolymers such as poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate Copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, Styrene-based copolymers such as styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer; acrylic resin, methacrylic resin, polyvinyl acetate, silicone Resin, polyes Le resins, polyamide resins, furan resins, epoxy resins, xylene resins.

These resins are used alone or as a mixture.

As a main component of the binder resin, a styrene copolymer, which is a copolymer of styrene and another vinyl monomer, is preferable from the viewpoint of developability and fixability.

The comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic Acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, monocarboxylic acid having a double bond such as acrylamide or a substituted product thereof; maleic acid,
Dicarboxylic acids having a double bond such as butyl maleate, methyl maleate and dimethyl maleate and their substituted products; vinyl esters such as vinyl chloride, vinyl acetate and vinyl benzoate; ethylene such as ethylene, propylene and butylene System olefins; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. These vinyl monomers are used alone or in combination of two or more.

The styrene copolymer is preferably cross-linked with a cross-linking agent such as divinylbenzene in order to widen the fixing temperature range of the toner and improve the offset resistance.

As the polymerizable monomer used for producing the toner of the present invention by the polymerization method, a vinyl polymerizable monomer capable of radical polymerization is used. As the vinyl polymerizable monomer, a monofunctional polymerizable monomer or a polyfunctional polymerizable monomer can be used.

Examples of the monofunctional polymerizable monomer include styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, and p-methylstyrene. n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, p-methoxy Styrene derivatives such as styrene and p-phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso
-Butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl Acrylic polymerizable monomers such as acrylate, dibutyl phosphate ethyl acrylate and 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate; tert
-Butyl methacrylate, n-amyl methacrylate,
Methacrylic polymerizable monomers such as n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate, dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; acetic acid Vinyl esters such as vinyl, vinyl propionate, vinyl butyrate, vinyl benzoate and vinyl formate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone. No.

Examples of the polyfunctional polymerizable monomer include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, and 1,6.
-Hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, 2,2'-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane Tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate,
1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy diethoxy) phenyl) propane, 2,
2'-bis (4- (methacryloxypolyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethanetetramethacrylate, divinylbenzene, divinylnaphthalene, divinylether, and the like.

In the present invention, the above-mentioned monofunctional polymerizable monomers may be used alone, in combination of two or more, or
The monofunctional polymerizable monomer and the polyfunctional polymerizable monomer described above are used in combination. Polyfunctional polymerizable monomers can also be used as crosslinking agents.

As the polymerization initiator used in the polymerization of the above-mentioned polymerizable monomer, an oil-soluble initiator and / or a water-soluble initiator is used. For example, as the oil-soluble initiator, 2,2′-azobisisobutyronitrile, 2,2 ′
-Azobis-2,4-dimethylvaleronitrile, 1,
Azo compounds such as 1'-azobis (cyclohexacy-1-carbonitrile) and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile; acetylcyclohexylsulfonyl peroxide, diisopropyl peroxycarbonate, decanolyl Peroxide,
Lauroyl peroxide, stearoyl peroxide, propionyl peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butylperoxyisobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, Peroxide initiators such as dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide and cumene hydroperoxide are exemplified.

Examples of the water-soluble initiator include ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-
Dimethyleneisobutyroamidine) hydrochloride, 2,2′-azobis (2-aminodinopropane) hydrochloride, azobis (isobutylamidine) hydrochloride, sodium 2,2′-azobisisobutyronitrile sulfonate, sulfuric acid Ferrous or hydrogen peroxide.

In the present invention, in order to control the degree of polymerization of the polymerizable monomer, a chain transfer agent, a polymerization inhibitor and the like may be further added and used.

As the crosslinking agent used in the toner of the present invention, a compound having two or more polymerizable double bonds is used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butanediol dimethacrylate; divinylaniline; Divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups. These are used alone or as a mixture.

The release agent used in the toner of the present invention includes polymethylene wax such as paraffin wax, polyolefin wax, microcrystalline wax and Fischer-Tropsch wax, amide wax, higher fatty acid, long-chain alcohol, ketone wax, and the like. Ester waxes and their derivatives such as graft compounds and block compounds are exemplified.

In the case where toner particles are formed by a melt-kneading pulverization method, the releasing agent is used in an amount of 1 part by weight per 100 parts by weight of the binder resin.
It is preferable to use 10 to 10 parts by mass.

When toner particles are directly formed in an aqueous medium, the binder resin 10 formed from a polymerizable monomer may be used.
The releasing agent is preferably contained in the toner particles in an amount of 5 to 40 parts by mass (more preferably 5 to 35 parts by mass) per 0 parts by mass.

In the toner production method based on polymerization, compared to the dry toner production method based on melt-kneading and pulverization, a large amount of release agent is easily encapsulated by a polar resin inside the toner particles. It is possible to use a template, which is particularly effective for the effect of preventing offset during fixing.

As the colorant used in the toner of the present invention, carbon black, a magnetic substance, and those toned to black using the following yellow / magenta / cyan colorants are used.

As the yellow colorant, as a pigment, a compound represented by a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex methine compound, or an allylamide compound is used. Specifically, C.I. I. Pigment Yellow 3, 7, 1
0, 12, 13, 14, 15, 17, 23, 24, 6
0, 62, 74, 75, 83, 93, 94, 95, 9
9, 100, 101, 104, 108, 109, 11
0, 111, 117, 123, 128, 129, 13
8, 139, 147, 148, 150, 166, 16
8, 169, 177, 179, 180, 181, 18
3, 185, 191: 1, 191, 192, 193, 1
99 and the like are preferably used. As a dye system, for example,
C. I. solventYellow 33, 56, 7
9, 82, 93, 112, 162, 163, C.I. . I.
Disperse Yellow 42, 64, 201,
211 and the like.

As the magenta coloring agent, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8: 2, 48: 3, 48: 4, 57: 1, 81: 1, 1
22, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254, C.I.
I. Pigment Violet 19 is particularly preferred.

As the cyan coloring agent, phthalocyanine compounds such as copper, aluminum and zinc and derivatives thereof, anthraquinone compounds, basic dye lake compounds and the like can be used. Specifically, C.I. I. Pigment Blue 1, 7, 1
5, 15: 1, 15: 2, 15: 3, 15: 4, 60,
62, 66 and the like are particularly preferably used.

These colorants can be used alone or as a mixture or in the form of a solid solution. The colorant of the present invention is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The colorant is used in an amount of 1 to 20 parts by mass per 100 parts by mass of the resin.

In the toner of the present invention, a charge control agent may be used in combination.

The following substances control the toner to be negatively charged.

For example, organic metal compounds and chelate compounds are effective, and examples thereof include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol. Further, urea derivatives, metal-containing salicylic acid-based compounds, metal-containing naphthoic acid-based compounds, boron compounds, quaternary ammonium salts, calixarenes, resin-based charge control agents and the like can be mentioned.

The following substances control the toner to be positively charged.

Nigrosine modified with nigrosine and fatty acid metal salts, etc., guanidine compounds, imidazole compounds, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate;
And onium salts such as phosphonium salts which are analogs thereof, lake pigments thereof, triphenylmethane dyes and these lake pigments. , Lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids; cyorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin borate And diorganotin borates, and a resin-based charge control agent. These can be used alone or in combination of two or more.

The charge control agent is preferably used in an amount of 0.01 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the binder resin.

When the toner of the present invention is a polymerization toner, a condensation resin may be added.

The condensation resin of the present invention includes, for example, polyester, polycarbonate, phenol resin, epoxy resin, polyamide, cellulose and the like. More preferably, polyester is desired in view of the variety of materials.

From the viewpoint of durability, the additive for improving various properties of the toner preferably has a particle diameter of 1/2 or less of the volume average diameter of the toner particles. The particle size of the additive means the average particle size of the toner particles obtained by observing the surface of the toner particles with an electron microscope. As additives for imparting these properties, for example, the following are used.

Examples of the fluidity-imparting agent include metal oxides (such as silicon oxide, aluminum oxide, and titanium oxide), carbon black, and carbon fluoride. Each of which has been subjected to a hydrophobic treatment is more preferable. As an abrasive, metal oxides (strontium titanate, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, etc.) , Calcium carbonate, etc.).

Examples of the lubricant include fluororesin powder (vinylidene fluoride, polytetrafluoroethylene, etc.) and fatty acid metal salts (zinc stearate, calcium stearate, etc.).

Examples of the charge control particles include metal oxides (tin oxide / titanium oxide, zinc oxide, silicon oxide, aluminum oxide, etc.) and carbon black.

These additives are used in an amount of 0.1 to 10 parts by mass, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the toner particles. These additives may be used alone or in combination of two or more.

The method for producing the toner of the present invention will be described below.

When the toner of the present invention is a pulverized toner, at least the binder resin and the colorant are kneaded and uniformly dispersed using a pressure kneader, an extruder, a media disperser, or the like. A method for producing toner particles having a desired degree of circularity by using mechanical means after finely pulverizing to a desired toner particle size by colliding with a target under a mechanical or jet stream, and further passing through a classification step; After the pulverization, there is a method of performing a wet or dry thermal sphering treatment.

When the toner of the present invention is a polymerization method,
Although there is no particular restriction, Japanese Patent Publication No. 36-102
No. 31, JP-A-59-53856 and JP-A-5-53856
A method of directly producing a toner using a suspension polymerization method described in JP-A No. 9-61842; producing a toner particle by directly polymerizing in the presence of a water-soluble polymerization initiator which is soluble in a monomer. Production of toner particles by an emulsion polymerization method typified by a soap-free polymerization method. In addition, production by an interfacial polymerization method such as a microcapsule production method, an in-situ polymerization method, a coacervation method, and the like can also be mentioned. further,
JP-A-62-106473 and JP-A-63-186.
No. 253, an interface association method of aggregating at least one or more types of fine particles to obtain a particle having a desired particle size, and the like.

A suspension polymerization method in which small toner particles can be easily obtained is particularly preferred. Further, a seed polymerization method in which a monomer is further adsorbed on the polymer particles once obtained and then polymerized using a polymerization initiator can also be suitably used in the present invention. At this time, it is also possible to use a compound having polarity dispersed or dissolved in the monomer to be adsorbed.

In the case of suspension polymerization, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer composition. As a dispersing agent to be used, for example, as an inorganic oxide, tricalcium phosphate,
Magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica, alumina, sodium dodecyl sulfate, etc. Is mentioned. As the organic compound, for example, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, starch and the like are used. It is preferable to use 0.1 to 5.0 parts by mass of these dispersants or dispersing aids with respect to 100 parts by mass of the polymerizable monomer. A surfactant of 0.001 to 0.1% by mass may be used in combination for making these dispersants finer. Specifically, commercially available nonionic and anionic-cationic surfactants can be used. For example, sodium dodecyl sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, calcium oleate and the like are preferably used.

Next, the carrier of the present invention will be described.

50% by volume of the carrier particles of the present invention
The measuring method of the particle size and the particle size distribution is as follows:
PATEC) dry disperser (Rodos <RODOS)
>) Using a laser diffraction particle size distribution analyzer (Heros <HELOS>) equipped with a feed air pressure of 3 ba.
The measurement was performed under the conditions of r and suction pressure of 0.1 bar.

The carrier particle size is preferably 50% particle size (D) on a volume basis, preferably 15 to 60 μm, and more preferably 25 to 50 μm. Further careers
The content of particles having a particle size of 2/3 or less (2D / 3 ≧) of the 50% particle size is preferably 5% by volume or less, more preferably 0.1 to 5% by volume.

If the 50% particle size of the carrier is less than 15 μm, it is not possible to prevent the carrier from adhering to the non-image area due to the particles on the fine particle side of the particle size distribution of the carrier. The layer may be damaged, resulting in charging roller contamination. 50 of career
When the% particle size is larger than 60 μm, the ability to impart charge to the toner is reduced, and the developing characteristics may be poor.

As the particle size distribution of the carrier of the present invention, 50
When the content of particles having a particle size of not more than 2/3 of the% particle size is more than 5% by volume, there is a tendency that the carrier adheres due to the fine powder of the carrier, thereby causing damage to the surface layer of the charging roller. As a result, the charging roller may be contaminated.

In the present invention, the specific resistance of the carrier is 1
It is preferably from × 10 ⁸ to 1 × 10 ¹⁶ Ω · cm,
More preferably, it is 1 × 10 ⁹ to 1 × 10 ¹⁵ Ω · cm.

When the specific resistance of the carrier is less than 1 × 10 ⁸ , the carrier is apt to adhere to the surface of the photoreceptor, to cause damage to the photoreceptor, or to cause image defects by being directly transferred to paper. Become. Further, the developing bias may leak through the carrier and disturb the electrostatic latent image drawn on the photosensitive drum.

If the specific resistance of the carrier exceeds 1 × 10 ¹⁶ Ω · cm, a sharp edge-enhanced image is easily formed, and the charge on the surface of the carrier hardly leaks.
In some cases, the image density may decrease due to the charge-up phenomenon, and fogging and scattering may occur due to the inability to apply the charge to the newly replenished toner.
Further, the toner may be charged with a substance such as the inner wall of the developing device, and the charge amount of the toner which should be applied may become non-uniform. In addition, image defects such as electrostatic adhesion of external additives are likely to occur.

The specific resistance of the carrier was measured using a powder insulation resistance meter manufactured by Vacuum Riko Co., Ltd.
Measurement conditions, 23 ° C., put left carrier for 24 hours or more 60% under the conditions in the measuring cell diameter ^{20mm (0.283cm 2), 11.8kPa (} 120g / cm 2)
, A thickness of 2 mm, and an applied voltage of 50 mm.
It was measured at 0V.

The magnetic properties of the carrier are 1000 / 4π
(KA / m) is preferably 20 to 10
0 (Am ² / kg), more preferably 30 to 65 (Am ² / kg)
/ Kg).

The carrier has a magnetization intensity of 100 (Am ² /
kg), the density of the magnetic brush formed on the developing sleeve at the developing pole decreases, the spike length becomes longer, and it becomes rigid. Eye irregularities are likely to occur, and particularly, the durability of the toner is likely to deteriorate due to copying or printing a large number of sheets.

The carrier has a magnetization intensity of 20 (Am ² / k
If the value is less than g), the magnetic force of the carrier is reduced even if the carrier fine powder is removed, the carrier is likely to adhere, and the toner transportability is likely to be reduced.

The measurement of the magnetic properties of the carrier was performed using an oscillating magnetic field type automatic magnetic property recording apparatus BHV-3 manufactured by Riken Denshi Co., Ltd.
5 was performed. As the measurement conditions, an external magnetic field of 1000 / 4π (kA / m) was created for the magnetic characteristics of the carrier powder, and the magnetization intensity at that time was determined. The carrier is packed in a cylindrical plastic container so that the carrier particles are sufficiently dense so that the carrier particles do not move, the magnetization moment is measured in this state, and the actual weight when the sample is placed is measured. And the intensity of magnetization (Am ² / kg).

In the present invention, examples of the metal compound particles used for the carrier core include magnetite or ferrite having magnetism represented by the following formula (1) or (2).

MO.Fe ₂ O ₃ ... (1) M.Fe ₂ O ₄ ... (2) (In the formula, M represents a trivalent, divalent or monovalent metal ion.)

M represents Mg, Al, Si, Ca, S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, B
a, Pb, and Li, which can be used alone or in combination.

Specific examples of the above-mentioned magnetic compound particles having magnetism include magnetite and Zn-Fe.
Ferrite, Mn-Zn-Fe ferrite, Ni-
Zn-Fe ferrite, Mn-Mg-Fe ferrite, Ca-Mn-Fe ferrite, Ca-Mg-Fe
Ferrite, Li-Fe ferrite and Cu-Zn
And iron-based oxides such as Fe-based ferrite.

Further, in the present invention, as the metal compound particles used for the carrier core, a mixture of the above-described magnetic metal compound and the following non-magnetic metal compound may be used.

As the non-magnetic metal compound, for example, A
l ₂ O ₃ , SiO ₂ , CaO, TiO ₂ , V ₂ O ₅ , CrO,
MnO ₂ , α-Fe ₂ O ₃ , CoO, NiO, CuO, Z
nO, SrO, include Y ₂ O ₃ and ZrO _2. In this case, one kind of metal compound can be used, but it is particularly preferable to use a mixture of at least two or more kinds of metal compounds. In this case, it is more preferable to use particles having similar specific gravities and shapes in order to increase the adhesion to the binder resin and the strength of the carrier core particles.

Specific examples of the combination include magnetite and hematite, and magnetite and γ-Fe
₂ O ₃ , magnetite and SiO ₂ , magnetite and Al ₂ O
_3, magnetite and TiO _2, magnetite and Ca-Mn
-Fe-based ferrite, magnetite and Ca-MgFe-based ferrite can be preferably used. Among them, a combination of magnetite and hematite can be particularly preferably used.

When the above-mentioned magnetic metal compound is used alone or in combination with a non-magnetic metal compound, the number average particle diameter of the magnetic metal compound is determined by the number average particle diameter of the carrier core. It is preferably 0.02 to 2 μm, and more preferably 0.05 to 1 μm.

When the number average particle size of the magnetic metal compound is less than 0.02 μm, it becomes difficult to obtain favorable magnetic properties. The number average particle size of the magnetic metal compound is 2
When it exceeds μm, it is difficult to obtain a carrier having a high strength and a preferable particle diameter due to uneven granulation.

When a mixture of a magnetic metal compound and a nonmagnetic compound is used, the number average particle diameter of the nonmagnetic metal compound is preferably 0.05 to 5 μm, more preferably 0.1 to 3 μm. Good to be. In this case, the number average particle diameter (average particle diameter ra) of the metal compound having magnetism,
The particle size ratio (rb / ra) to the number average particle size (average particle size rb) of the nonmagnetic metal compound is preferably 1.0 to 5.0.
0, more preferably 1.2 to 5.0.

The non-magnetic metal compound has a number average particle diameter of 0.1.
When the thickness is less than 05 μm, favorable resistance cannot be obtained, and the carrier tends to adhere. When the number average particle size of the nonmagnetic metal compound exceeds 5 μm, it is difficult to obtain a carrier having a preferable particle size with high strength due to non-uniform granulation.

Further, when rb / ra is less than 1.0, ferromagnetic metal compound particles having a low specific resistance tend to emerge on the surface, it is difficult to increase the specific resistance of the carrier core, and the effect of preventing carrier adhesion is obtained. It is difficult to obtain. When rb / ra exceeds 5.0, the strength of the carrier tends to decrease, and the carrier is likely to be destroyed.

The number average particle diameter of the metal oxide was measured by a transmission electron microscope H-800 manufactured by Hitachi, Ltd.
Using a photographic image magnified 00 to 20000 times, 300 or more particles having a particle size of 0.01 μm or more were randomly extracted, and an image processing analysis device Luzex3 manufactured by Nireco Co., Ltd. was used.
Was measured as the metal oxide particle size with the Feret diameter in the horizontal direction, and averaged to calculate the number average particle size.

The specific resistance of the metal compound dispersed in the binder resin is such that the specific resistance of the magnetic metal compound particles is 1 × 1.
It is preferably in the range of 0 ³ Ω · cm or more. In particular, when a magnetic metal compound and a nonmagnetic compound are used in combination, the specific resistance of the magnetic metal compound particles is 1
× 10 ³ Ω · cm or more is preferable, and the other nonmagnetic metal compound particles preferably have higher specific resistance than the magnetic metal compound particles, and are preferably used.
The specific resistance of the nonmagnetic metal compound used in the present invention is 1 × 10
^It is preferably ⁸ Ω · cm or more, more preferably 1 × 10 ¹⁰ Ω · cm or more.

The specific resistance of the magnetic metal compound particles is 1
When the content is less than × 10 ³ Ω · cm, it is difficult to obtain a desired high specific resistance even if the content is reduced, which leads to charge injection, image quality deterioration and carrier adhesion. When a mixture of a magnetic metal compound and a nonmagnetic compound is used, the specific resistance of the nonmagnetic metal compound is 1 × 10 ⁸ Ω · cm.
If it is less than the specific resistance of the magnetic carrier core becomes low,
It becomes difficult to obtain the effects of the present invention.

In the present invention, the specific resistance of a magnetic metal compound and a non-magnetic metal compound is measured according to the method of measuring the specific resistance of carrier particles.

In the carrier core of the present invention, the content of the metal compound is preferably 80% with respect to the carrier core.
The content is preferably up to 99% by mass.

When the content of the metal compound is less than 80% by mass, the chargeability tends to be unstable, and the carrier is charged particularly in a low-temperature and low-humidity environment, and the residual charge tends to remain. And an external additive easily adhere to the surface of the carrier particles, and a proper specific gravity cannot be obtained. When the content of the metal compound exceeds 99% by mass, the strength of the carrier decreases, and problems such as cracking of the carrier due to durability tend to occur.

Further, in a preferred embodiment of the present invention, in the carrier core containing a mixture of a magnetic metal compound and a nonmagnetic compound, the content of the magnetic metal compound in the entire metal compound is preferably The content is preferably 50 to 95% by mass, more preferably 55 to 95% by mass.

When the content of the metal compound having magnetism in the whole metal compound is less than 50% by mass, the resistance of the core is improved, but the magnetic force as a carrier is reduced and the carrier adhesion is reduced. May be invited. If the content of the magnetic metal compound in the whole metal compound exceeds 95% by mass, depending on the specific resistance of the magnetic metal compound, it may not be possible to achieve a more desirable high core resistance.

The binder resin of the carrier core particles used in the present invention is a thermosetting resin, and a part or all of the binder resin is 3%.
It is preferable that the resin is a cross-linked resin. Thereby, the dispersed metal compound particles can be firmly bound, so that the strength of the carrier core can be increased, and the detachment of the metal compound hardly occurs even in a large number of copies,
Furthermore, the coating resin can be coated better,
As a result, it is easy to control within the scope of the present invention.

The method for obtaining the magnetic material-dispersed carrier core is not particularly limited to the method described below. However, in the present invention, a solution in which the monomer and the solvent are uniformly dispersed or dissolved is used. From the inside, the production method of the polymerization method of generating particles by polymerizing the monomer, particularly, by subjecting the metal oxide dispersed in the carrier core particles to lipophilic treatment, a sharp particle size distribution, fine powder A method for obtaining a small magnetic substance dispersed resin carrier core is as follows.
It is preferably used.

In the present invention, in the case of a carrier used in combination with a small particle size toner having a weight average particle size of 1 to 10 μm in order to achieve high image quality, the carrier particle size is also reduced according to the particle size of the toner. It is preferable to reduce the particle size, and the above-described production method is particularly preferable because even if the carrier particle size is reduced, a carrier having a small amount of fine powder can be produced regardless of the average particle size.

As the monomer used for the binder resin of the carrier core particles, a radical polymerizable monomer can be used. For example, styrene; o-methylstyrene,
Styrene derivatives such as m-methylstyrene, p-methoxystyrene, p-ethylstyrene, p-tert-butylstyrene; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, n-propyl acrylate, acrylic Isobutyl acid, octyl acrylate,
Dodecyl acrylate, 2-ethylhexyl acrylate,
Stearyl acrylate, 2-chloroethyl acrylate,
Acrylic esters such as phenyl acrylate; methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-methacrylic acid Ethylhexyl, stearyl methacrylate, phenyl methacrylate,
Methacrylic esters such as dimethylaminomethyl methacrylate, diethylaminoethyl methacrylate, and benzyl methacrylate; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate; acrylonitrile, methacrylonitrile, acrylamide; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, vinyl ethers such as n-butyl ether, isobutyl ether, β-chloroethyl vinyl ether, phenyl vinyl ether, p-methylphenyl ether, p-chlorophenyl ether, p-bromophenyl ether, p-nitrophenyl vinyl ether, p-methoxyphenyl vinyl ether; butadiene And diene compounds such as

These monomers can be used alone or as a mixture, and a suitable polymer composition capable of obtaining preferable characteristics can be selected.

As described above, the binder resin of the carrier core particles is preferably three-dimensionally cross-linked. However, as a cross-linking agent for three-dimensionally cross-linking the binder resin,
It is preferable to use a crosslinking agent having two or more polymerizable double bonds per molecule.

Examples of such a crosslinking agent include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and 1,3. -Butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetra Acrylate, pentaerythritol dimethacrylate, pentaerythritol tetramethacrylate, Roll Acro carboxymethyl dimethacrylate, N, N-divinyl aniline, divinyl ether, and a divinyl sulfide and divinyl sulfone. These may be used by mixing two or more kinds as appropriate. The cross-linking agent can be previously mixed with the polymerizable mixture, or can be added as needed during the polymerization.

Other monomers for the binder resin of the carrier core particles include bisphenols and epichlorohydrin as starting materials for the epoxy resin; phenols and aldehydes of the phenol resin; ureas and aldehydes of the urea resin; melamine and aldehydes. No.

The most preferred binder resin is a phenolic resin. The starting materials are phenol, m
-Phenol compounds such as cresol, 3,5-xylenol, p-alkylphenol, resorcil, p-tert-butylphenol, and aldehyde compounds such as formalin, paraformaldehyde and furfural. Particularly, a combination of phenol and formalin is preferred.

When these phenol resins or melamine resins are used, a basic catalyst can be used as a curing catalyst. As the basic catalyst, various catalysts used in the production of ordinary resol resins can be used. Specific examples include amines such as aqueous ammonia, hexamethylenetetramine, diethyltriamine and polyethyleneimine.

In the present invention, the metal compound contained in the carrier core is subjected to lipophilic treatment to sharpen the particle size distribution of the magnetic carrier particles and prevent the metal compound particles from being detached from the carrier. Preferred above.
In the case of forming carrier core particles in which a lipophilic metal compound is dispersed, particles insoluble in a solution are generated at the same time as the polymerization reaction proceeds from a liquid in which a monomer and a solvent are uniformly dispersed or dissolved. At that time, it is considered that the metal oxide has an effect of uniformly and densely taking in the inside of the particles and an effect of preventing aggregation of the particles and sharpening the particle size distribution.

Further, when a metal compound subjected to lipophilic treatment is used, it is not necessary to use a suspension stabilizer such as calcium fluoride, and the suspension stabilizer remains on the carrier surface, thereby inhibiting the chargeability. It is possible to prevent the nonuniformity of the coating resin at the time of coating and the inhibition of the reaction when coating with a reactive resin such as a silicone resin. In addition, the absence of the suspension stabilizer on the surface and the associated adverse effects are eliminated, thereby facilitating control within the scope of the present invention.

In the lipophilic treatment, an organic compound having one or more functional groups selected from an epoxy group, an amino group and a mercapto group, or a lipophilic treatment agent which is a mixture thereof is used. Is preferred. In particular, an epoxy group is preferably used in order to easily achieve the range of the present invention and to obtain a carrier having a stable charge providing ability.

The magnetic metal oxide particles are preferably treated with 0.1 to 10 parts by mass, more preferably 0.2 to 6 parts by mass, of the lipophilic treatment agent per 100 parts by mass of the magnetic metal oxide particles. Is preferred in order to increase the lipophilicity and hydrophobicity of the magnetic metal oxide particles.

Examples of the lipophilic treating agent having an epoxy group include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β
-(3,4-epoxycyclohexyl) trimethoxysilane, epichlorohydrin, glycidol and styrene-glycidyl (meth) acrylate copolymer.

Examples of the lipophilic treatment agent having an amino group include γ-aminopropyltrimethoxysilane, γ-aminopropylmethoxydiethoxysilane, γ-aminopropyltriethoxysilane, and N-β (aminoethyl)-
γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, ethylenediamine, ethylenetriamine, styrene-dimethylamino (meth) acrylate Ethyl copolymer and isopropyl tri (N-aminoethyl) titanate are used.

As the lipophilic treatment agent having a mercapto group, for example, mercaptoethanol, mercaptopropionic acid and γ-mercaptopropyltrimethoxysilane are used.

The resin coating the carrier core surface is not particularly limited. Specifically, for example, polystyrene, acrylic resin such as styrene-acrylic copolymer, vinyl chloride, vinyl acetate, polyvinylidene fluoride resin, fluorocarbon resin, perfluorocarbon resin, solvent-soluble perfluorocarbon resin, polyvinyl alcohol, polyvinyl acetal, Polyvinyl pyrrolidone, petroleum resin, cellulose, cellulose derivative, novolak resin, low molecular weight polyethylene, saturated alkyl polyester resin, aromatic polyester resin, polyamide resin, polyacetal resin, polycarbonate resin, polyether sulfone resin, polysulfone resin, polyphenylene sulfide resin, poly Ether ketone resin, phenol resin, modified phenol resin, maleic resin, alkyd resin, epoxy resin, acrylic resin, anhydrous male Unsaturated polyester obtained by polycondensation of emissions and terephthalic acid and polyhydric alcohol, urea resins, melamine resins,
Urea-melamine resin, xylene resin, toluene resin, guanamine resin, melamine-guanamine resin, acetoguanamine resin, gliptal resin, furan resin, silicone resin, polyimide resin, polyamideimide resin, polyetherimide resin and polyurethane resin. it can.

Among them, silicone resins are preferably used from the viewpoint of adhesion to the core and prevention of spent. The silicone resin can be used alone, but is preferably used in combination with a coupling agent in order to increase the strength of the coating layer and control the charging to a preferable level. Further, the above-mentioned coupling agent is preferably used as a so-called primer agent, a part of which is treated on the carrier core surface before coating the resin, and the subsequent coating layer has a covalent bond. , Can be formed with higher adhesion.

As the coupling agent, aminosilane is preferably used. As a result, a positively chargeable amino group can be introduced into the carrier surface, and the toner can be favorably imparted with negative charge characteristics. Furthermore, the presence of the amino group activates both the lipophilic treatment agent preferably treated with the metal compound and the silicone resin, so that the adhesion between the silicone resin and the carrier core is further enhanced, and at the same time, the curing of the resin is performed. , A stronger coating layer can be formed.

During the coating treatment of the coating layer, the coating is preferably performed under reduced pressure at a temperature of 30 ° C. to 80 ° C.

Although the reason is not clear, it is expected to be described in the following (1) to (3). (1) The water content of the carrier core is used to activate the resin, and the water content of the entire carrier can be appropriately controlled. (2) An appropriate reaction proceeds in the coating step, and the coating material is uniformly and smoothly coated on the carrier core surface. (3) In the baking step, low-temperature treatment at a temperature of at least 160 ° C. or less can be performed, and excessive crosslinking of the resin can be prevented, and the durability of the coating layer can be increased.

In the final step, 23 ° C., 60% R
It is preferable to perform a humidity control step by leaving the apparatus in a normal environment such as H for at least 24 hours or more. As a result, it is possible to quickly control the moisture that has disappeared by applying heat during the process to the configuration of the present invention. In addition, the so-called “self-charging of carrier”, which reduces the performance of applying toner to the toner due to the carrier itself retaining charge due to contact between carriers or contact with the walls of the device during the process, is reduced. This makes it possible to give a stable charge to the toner.

The measuring method will be described below.

The circle equivalent diameter, circularity and frequency distribution of the toner in the present invention are used as a simple method for quantitatively expressing the shape of the toner particles. In the present invention, the flow type particle image measurement is used. The measurement was performed using an apparatus FPIA-1000 (manufactured by Toa Medical Electronics Co., Ltd.), and calculated using the following equation.

[0206]

(Equation 1)

Here, the “particle projection area” is the area of the binarized toner particle image, and is the “perimeter of the particle projection image”.
Is defined as the length of the contour obtained by connecting the edge points of the toner particle image.

The circularity in the present invention is an index indicating the degree of unevenness of the toner particles. The circularity is 1.00 when the toner particles are perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated. Become.

In the present invention, the circle-equivalent number average diameter D ₁ and the particle size standard deviation SDd which mean the average value of the number-based toner particle size frequency distribution are the particle size (central value) at the dividing point i of the particle size distribution. Where di is the frequency and fi is the frequency.

[0210]

(Equation 2)

Further, the average circularity and the circularity standard deviation SDc, which mean the circularity frequency distribution, are as follows, where the circularity (center value) at the dividing point i of the particle size distribution is ci and the frequency is fci. It is calculated from the formula.

[0212]

(Equation 3)

As a specific measuring method, 10 ml of ion-exchanged water from which impurity solids and the like have been removed in advance is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added thereto as a dispersant. Then, about 0.02 g of a measurement sample is further added, and the mixture is uniformly dispersed. As a means for dispersing, an ultrasonic dispersing machine UH-50 type (manufactured by SMT Corporation) equipped with a titanium alloy chip of 5φ as a vibrator is used, and a dispersion treatment for 5 minutes is used to prepare a dispersion for measurement. At this time, the dispersion is appropriately cooled so that the temperature of the dispersion does not become 40 ° C. or higher.

For the measurement of the shape of the toner particles, the above-mentioned flow type particle image measuring device was used.
The concentration of the dispersion liquid is readjusted so as to be 00 to 15000 particles / μl, and 1,000 or more toner particles are measured. After the measurement, using this data, the equivalent circle diameter and circularity frequency distribution of the toner are obtained.

[0215]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. “Parts” means “parts by mass”.

The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process, a contact charging type, a reversal developing type, a cleaner-less type, and an A3 size maximum sheet passing size.

The photosensitive drum of this embodiment is a negatively chargeable organic photoconductor (OPC) having an outer diameter of 50 mm and a process speed (peripheral speed) of 100 mm / sec around the center support shaft as indicated by an arrow. It is driven to rotate counterclockwise.

The developing constitution in the present invention is as follows.

As shown in FIG. 3, the developing sleeve 4b
The closest distance to the photosensitive drum 1 (referred to as S-Dgap)
Is maintained at 350 μm, and is opposed to and close to the photosensitive drum 1. The facing portion between the photosensitive drum 1 and the developing sleeve 4b is a developing portion c. The developing sleeve 4b is driven to rotate in a direction opposite to the direction in which the photosensitive drum 1 moves in the developing section c. The developing container 4 is placed on the outer peripheral surface of the developing sleeve 4b by the magnetic force of the magnet roller 4c in the sleeve.
A part of the two-component developer 4e in a is adsorbed and held as a magnetic brush layer, is conveyed in rotation with the rotation of the sleeve, is layered into a predetermined thin layer by the developer coating blade 4d, and is exposed in the developing section c. The surface of the photosensitive drum is brought into contact with the surface of the drum 1 and is rubbed appropriately.

A predetermined developing bias is applied to the developing sleeve 4b from the power source S2. In this example, the developing bias voltage for the developing sleeve 4b is a DC voltage (Vdc).
And an alternating voltage (Vac). More specifically, it is an oscillating voltage in which a DC voltage; -350 V AC voltage; 1500 V is superimposed.

In this embodiment, the toner charge amount control means 7
Is a brush-shaped member having an appropriate conductivity. The brush portion is disposed in contact with the surface of the photosensitive drum 1, and a negative voltage is applied from the power supply S4. e is a contact portion between the brush portion and the surface of the photosensitive drum 1. The transfer residual toner on the photosensitive drum 1 that passes through the toner charge amount control means 7 has its charge polarity adjusted to the negative polarity, which is the normal polarity.

Hereinafter, a method of manufacturing the charging roller having the specifications shown in FIG. 4 will be described.

(Production of Charging Roller No. 1) ・ Styrene-butadiene rubber (SBR) 100 parts ・ Carbon black 30 parts ・ Zinc oxide 5 parts ・ Fatty acid 2 parts A sealed mixer in which the above materials were adjusted to 60 ° C. 10
After kneading for 20 minutes, 20 parts of naphthenic oil is added to 100 parts of SBR and kneaded for 20 minutes with a closed mixer cooled to 20 ° C. to prepare a raw material compound. Further, styrene-butadiene rubber (SBR) 100 as a raw material rubber is used.
To one part, 0.5 part of sulfur as a vulcanizing agent and 1 part of a thiazole type and 1 part of a thiuram type as a vulcanization accelerator are added to the raw material compound and kneaded for 10 minutes by a two-roll machine cooled to 20 ° C. Using this compound, an elastic layer 2b was vulcanized by transfer molding around a stainless steel conductive support 2a having a diameter of 6 mm and a length of 320 mm.

The surface roughness of the charging roller was determined by polishing the roller surface at this time.

The 10-point average surface roughness of the polished elastic layer roller was Rz = 11.5 μm.

Also, 100 parts of epichlorohydrin rubber and 30 parts of titanium oxide are dispersed and dissolved in a solvent of toluene to prepare a coating for the resistance control layer 2c. This paint was applied on the elastic layer 2b by dipping to form a resistance control layer 2c having a thickness of 700 μm.

Further, a surface layer 2d was formed on the formed resistance control layer 2c as follows.

As a material for the surface layer 2d, 100 parts of a polyurethane resin and 90 parts of titanium oxide are dispersed and dissolved in a solvent of methyl ethyl ketone to prepare a coating for a surface layer. This paint is applied on the resistance control layer 2c by dipping to form a surface layer 2d having a thickness of 10 μm. 1 was obtained. The ten-point average surface roughness (Rz) was 1.6 μm.

(Production of Charging Roller No. 2) 1, the Rz of the elastic layer roller 2b after polishing was set to 14.5 μm, and the other rollers were charged roller Nos. In the same manner as in the production method of No. 1, charging roller No. 4 having a surface roughness (Rz) of 4.4 μm was finally obtained. 2 was obtained.

(Production of Charging Roller No. 3) Rz of the elastic layer roller 2b after polishing was set to 20.5 μm by using a process coarser than the polishing of No. 2, and the other charging roller Nos. In the same manner as in the production method of No. 1, the charging roller No. having a surface roughness (Rz) of 8.0 μm was finally obtained. 3 was obtained.

Hereinafter, a method for producing a carrier will be described.

(Preparation of Carrier I) After mixing and dispersing a phenol / formaldehyde monomer (50:50) in an aqueous medium, 0.25 μm magnetite particles 61 surface-treated with a titanium coupling agent were added to the monomer mass.
0 parts and 390 parts of 0.6 μm hematite particles are uniformly dispersed, and the monomer is polymerized while appropriately adding ammonia. The magnetic particle-encapsulated spherical magnetic resin carrier core material 1 (average particle diameter 35 μm, saturation magnetization 40 Am ² / kg) ) Got.

On the other hand, toluene 20 parts, butanol 20
Parts, 20 parts of water and 40 parts of ice in a four-necked flask, and with stirring, 15 mol of CH ₃ SiCl ₃ and (CH ₃ ) ₂ SiC
40 parts of a mixture with 10 mol of l ₂ was added, and the mixture was further stirred for 30 minutes and then subjected to a condensation reaction at 60 ° C. for 1 hour. Thereafter, the siloxane was sufficiently washed with water and dissolved in a mixed solvent of toluene, methyl ethyl ketone and butanol to prepare a silicone varnish having a solid content of 10%.

To the silicone varnish, 2.0 parts of ion-exchanged water and 2.0 parts of
Parts of the following curing agent (1), 1.0 part of the following aminosilane coupling agent (2), and 5.0 parts of the following silane coupling agent (3) were simultaneously added to prepare a carrier coating solution I. This solution I was applied to 100 parts of the above-mentioned carrier core material using a coating machine (a Spira coater manufactured by Okada Seiko Co., Ltd.) so that the resin coating amount was 1 part.
I got

This carrier has a 50% particle size of 35 μm, a content of particles having a particle size of 2/3 or less (2D / 3 ≧) of the 50% particle size is 4.1% by volume, and SF-1 Is 11
It was 2. Further, the specific resistance is 6 × 10 ¹³ Ωcm,
The saturation magnetization was 42 Am ² / kg.

[0236]

Embedded image

[0237]

Embedded image

[0238]

Embedded image

(Production of Carrier II) After mixing and dispersing a phenol / formaldehyde monomer (50:50) in an aqueous medium, 0.25 μm magnetite particles 6 surface-treated with a titanium coupling agent were added to the monomer mass.
Forty parts and 250 parts of 0.6 μm hematite particles are uniformly dispersed, and the monomer is polymerized while appropriately adding ammonia. The magnetic particle-containing spherical magnetic resin carrier core material 2 (average particle diameter 34 μm, saturation magnetization 48 Am ² / kg) ) Got. Except for this, carrier II is manufactured in the same manner as carrier I.
Was manufactured.

The carrier obtained had a 50% particle size of 34 μm.
And a particle size of 2/3 or less of the 50% particle size (2D / 3 ≧)
Was 4.3 volume%, and the value of SF-1 was 112. Further, the specific resistance was 9 × 10 ¹¹ Ωcm, and the saturation magnetization was 50 Am ² / kg.

(Production of Carrier III) After mixing and dispersing a phenol / formaldehyde monomer (50:50) in an aqueous medium, 400 parts of 0.25 μm magnetite particles surface-treated with a titanium coupling agent were added to the monomer mass. And 450 parts of 0.6 μm hematite particles are uniformly dispersed, and the monomer is polymerized while appropriately adding ammonia to form a spherical magnetic resin carrier core material 3 containing magnetic particles (average particle diameter 33 μm, saturation magnetization 20 Am ² / kg). Obtained.
Except for this, the carrier I is manufactured in the same manufacturing method as the carrier I.
II was prepared.

The carrier obtained had a 50% particle size of 33 μm.
And a particle size of 2/3 or less of the 50% particle size (2D / 3 ≧)
Was 4.5% by volume, and the value of SF-1 was 112. Further, the specific resistance was 7 × 10 ¹⁴ Ωcm, and the saturation magnetization was 22 Am ² / kg.

(Production of Carrier IV) 15 parts of MgO, M
After pulverization using 10 parts of nO and 75 parts of Fe ₂ O ₃ ,
After adding water and granulating, the mixture is fired at 1250 ° C., and the content of particles having a 50% diameter by volume average of 34 μm and a particle diameter of 2/3 or less (2D / 3 ≧) of the 50% particle diameter is reduced. 9.2% by volume
Ferrite carrier core material 4 was obtained.

The above core material was coated with a resin in the same manner as in the case of the carrier I to obtain a coated carrier IV. The SF-1 value of this carrier was 125. Furthermore, the specific resistance is 2.5
× 10 ¹² Ωcm, and the saturation magnetization was 55 Am ² / kg.

(Manufacture of Carrier V) By classifying the carrier I, a carrier V having a 50% diameter by volume average of 66 μm was obtained.

(Production of Carrier VI) By classifying the carrier I, the 50% diameter by volume average was 12 μm.
Was obtained.

(Production of Carrier VII) The ferrite carrier core material 4 was pulverized and classified, and the 50% diameter by volume average was 36 μm, and the particle diameter (2D / 3) was 2/3 or less of the 50% particle diameter.
A ferrite carrier core material having a content of particles (≧) of 4.1% by volume was obtained.

The above core material was coated with a resin in the same manner as in Carrier I to obtain Carrier VII. SF of this carrier
The value of -1 was 137.

Hereinafter, a method for producing a toner will be described.

(Production of Black Toner No. 1) The black toner used in the present invention was prepared as follows. In a two-liter four-necked flask equipped with a high-speed stirrer TK-homomixer, 910 parts of ion-exchanged water, 2 parts of polyvinyl alcohol, and 1 part of sodium dodecyl sulfate were added, and the number of rotations was adjusted to 12,000, To obtain a dispersant system.

On the other hand, the dispersoid system includes:-80 parts of styrene monomer-20 parts of 2-ethylhexyl acrylate monomer-10 parts of grafted carbon black (50% of carbon content)-5 parts of saturated polyester resin (propylene oxide) (Polycondensate of modified bisphenol A and terephthalic acid)-1 part of oxycarboxylic acid compound-20 parts of low softening point substance (paraffin wax) After dispersing the above mixture for 3 hours using a media disperser, it is a polymerization initiator. A dispersion to which 3 parts of 2,2′-azobis (2,4-dimethylvaleronitrile) was added was charged into the dispersion medium and granulated for 8 minutes while maintaining the rotation speed.
Then, the stirrer was replaced with a propeller stirring blade from the high-speed stirrer, the internal temperature was raised to 60 ° C, polymerization was continued at 150 rpm for 4 hours, and then the temperature was raised to 80 ° C over 1 hour, and then polymerization was performed for 5 hours. Continued.

After completion of the polymerization, the slurry was cooled, washed with water and dried to obtain black particles. Obtained black particles 10
0 parts of the titania fine powder which has been subjected to the hydrophobic treatment
2 parts and uniformly fixed using a Henschel mixer (manufactured by Mitsui Miike Koki Co., Ltd.). 1 was obtained. The obtained black toner No. The number average diameter D 1 of the circle-equivalent number of ₁ was 6.2 μm, and the average circularity was 0.972.

(Production of Black Toner No. 2) Except that the granulation time of the dispersoid in the dispersion medium was set to 15 minutes,
Black toner No. The black toner No. 2 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.1 μm and an average circularity of 0.970.

(Production of Black Toner No. 3) Saturated polyester resin 100 parts (polycondensate of propylene oxide-modified bisphenol A and phthalic acid) Grafted carbon black pigment (carbon content 50%) 10 parts Oxy Carboxylic acid compound 4 parts ・ Low softening point substance 4 parts (paraffin wax)

These are sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized by an air jet method. It was pulverized and further classified to a desired particle size. Thereafter, 910 parts of ion-exchanged water, 2 parts of polyvinyl alcohol, and 1 part of sodium dodecyl sulfate were added to a two-liter four-necked flask equipped with a propeller stirrer, and the number of revolutions was adjusted to 300.
Heated to 0 ° C., heat-spheroidized the pulverized toner,
Classify the black toner No. 3 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.2 μm and an average circularity of 0.960.

(Production of Black Toner No. 4) Saturated polyester resin 100 parts (polycondensate of propylene oxide-modified bisphenol A and phthalic acid) Grafted carbon black pigment (carbon content 50%) 10 parts Oxy Carboxylic acid compound 4 parts ・ Low softening point substance 4 parts (paraffin wax) These are sufficiently premixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, and cooled using a hammer mill to about 1-2 mm. And coarsely pulverized and further classified. Other than this, the black toner No. No. 1 in the same manner as in the production method of No. 1. 4 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.3 μm and an average circularity of 0.938.

(Production of Yellow Toner No. 1) In the same manner as in the production method of the yellow toner No. 1 except that the colorant in the production method 1 was changed to a benzimidazolone pigment. 1 was obtained. Number average diameter D of the obtained toner
₁ was 6.1 μm, and the average circularity was 0.973.

(Production of Yellow Toner No. 2) 100 parts of saturated polyester resin (polycondensate of propylene oxide-modified bisphenol A and phthalic acid) 7 parts of benzimidazolone pigment 4 parts of oxycarboxylic acid compound Low 4 parts of softening point substance (paraffin wax) These are sufficiently premixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, cooled, coarsely crushed using a hammer mill to about 1-2 mm, and then air jetted. It was pulverized with a pulverizer according to the method and further classified. Other than this, the black toner No. No. 1 in the same manner as in the production method of No. 1. 2 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.3 μm and an average circularity of 0.937.

(Production of Magenta Toner No. 1) Magenta toner No. 1 was prepared in the same manner as in the production method of Example 1 except that the colorant was changed to a quinacridone pigment.
1 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.3 μm and an average circularity of 0.970.

(Production of Magenta Toner No. 2) 100 parts of saturated polyester resin (polycondensate of propylene oxide-modified bisphenol A and phthalic acid) 7 parts of quinacridone pigment 4 parts of oxycarboxylic acid compound 4 parts of low softening point 4 parts of substance (paraffin wax) These are sufficiently premixed by a Henschel mixer, melt-kneaded by a twin-screw extruder, cooled, roughly ground to about 1 to 2 mm using a hammer mill, and then air-jetted. It was pulverized with a pulverizer and further classified. Other than this, the black toner No. Magenta Toner No. 2 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.3 μm and an average circularity of 0.936.

(Production of Cyan Toner No. 1) Cyan toner No. 1 was prepared in the same manner except that the colorant in the production method was changed to a copper phthalocyanine pigment.
1 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.0 μm and an average circularity of 0.971.

(Production of Cyan Toner No. 2) Saturated polyester resin 100 parts (polycondensate of propylene oxide-modified bisphenol A and phthalic acid) Copper phthalocyanine pigment 7 parts Oxycarboxylic acid compound 4 parts Low softening 4 parts of point substance (paraffin wax) These were sufficiently premixed with a Henschel mixer, melt-kneaded with a twin-screw extruder, cooled, coarsely crushed using a hammer mill to about 1-2 mm, and then air jetted And further classified. Other than this, the black toner No. Cyan toner No. 1 in the same manner as in the production method 2 was obtained. The obtained toner had a circle-equivalent number average diameter D ₁ of 6.3 μm and an average circularity of 0.938.

An embodiment will be described below.

<Examples and Comparative Examples> Black Toner N
o. 1 and carrier No. 1 was mixed at a toner concentration of 8% to prepare a black two-component developer.

Next, under a high temperature and high humidity environment (27 ° C./70%)
Then, using a laser beam printer of A3 size having the configuration shown in FIG. 3, one solid image having an image area ratio of 100% is output, and then an image having an image area ratio of 5% is continuously output on 5000 sheets. One solid image having an image area ratio of 100% was output. Thereafter, items relating to the following effects were measured or observed for the initial image and the image after passing 5,000 sheets. Table 3 shows the results.

Hereinafter, Examples 2 to 9 and Comparative Examples 1 to 10
Table 1 shows combinations of the toner, carrier and charging roller. Table 2 summarizes characteristic values and image forming conditions. The evaluation results are shown in Table 3 as in Example 1.

[0267]

[Table 1]

[0268]

[Table 2]

[0269]

[Table 3]

[Image Evaluation Method] (Measurement of fog) The measurement of fog was carried out using REFLECTOM.
ETER MODEL TC-6DS (Tokyo Denshoku)
And was calculated by the following equation. The smaller the fog value, the better. Fog (reflectance;%) = (reflectivity of standard paper;%)-(reflectance of white solid portion of sample;%) A: 1.2% or less B: Over 1.2% and 1.6% or less C: more than 1.2% and 2.0% or less D: more than 2.0%

(Transferability) The transferability was evaluated by observing a solid image having an area ratio of 100% on the obtained transfer paper. The evaluation was A, B, C, D. A: Not recognized at all. B: 1 to 3 transfer defects with toner particles as nuclei. C: 4 to 6 transfer defects with toner particles as nuclei. D: 7 or more transfer defects with toner particles as nuclei.

(Charging Roller Contamination) The charging roller contamination was evaluated by observing the roller surface visually, further observing image defects, and based on the following evaluation criteria. A: No defect is recognized on both the roller surface and the image. B: In the latter half of the durability, some dirt is observed on the roller surface,
Does not appear in the image. C: In the latter half of the durability, the roller surface is slightly stained, and the image is slightly uneven. D: In the latter half of the endurance, the roller surface is heavily stained, and the image becomes uneven.

(Scattering of Toner) Toner scattering was evaluated by observing the contamination of the outer surface of the upstream toner scattering suppressing portion and the downstream toner scattering suppressing portion of the developing container with toner and the contamination of the toner other than the developing container with toner. It was evaluated based on: A: Not recognized at all. B: Some dirt is observed on the outer surface of the toner scattering suppressing portion on the upstream side of the developing container, but no dirt is recognized on the outer surface of the toner scattering suppressing portion on the downstream side. C: Stain is observed on the outer surface of the toner scattering suppressing portion on the upstream side of the developing container and on the outer surface of the toner scattering preventing portion on the downstream side, but no stain is observed on the portions other than the developing container. D: Stain is observed in areas other than the developing container.

[0274]

According to the present invention having the above structure, a cleaner-less image forming method can be provided, and even when a large number of continuous prints are performed in a high-temperature and high-humidity environment, good fog suppression and good durability can be obtained. Excellent stability, good prevention of contamination on the charging roller, and good transferability.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of an image forming apparatus applicable to the present invention.

FIG. 2 is a schematic explanatory view showing another example of the image forming apparatus applicable to the present invention.

FIG. 3 is a schematic explanatory view showing another example of the image forming apparatus applicable to the present invention.

FIG. 4 is a schematic explanatory view showing an example of a charging roller applicable to the present invention.

FIG. 5 is a schematic explanatory view showing an example of an electrophotographic photosensitive member applicable to the present invention.

FIG. 6 is a schematic explanatory view showing another example of the electrophotographic photosensitive member applicable to the present invention.

FIG. 7 is a schematic explanatory view showing another example of the electrophotographic photosensitive member applicable to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor (image carrier) 2 Charging means 3 Information writing means 4 Developing device 5 Transfer device 6 Fixing device 7 Toner charge amount control means

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/02 102 G03G 9/10 351 15/08 507 15/08 507B (72) Inventor Shinya Taniuchi Tokyo 3-30-2 Shimomaruko, Ota-ku Canon Inc. (72) Katsuyuki Nonaka Inventor 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F-term (reference) 2H005 AA06 AA15 BA03 BA06 BA15 CA14 CA15 CA17 CB03 CB04 DA03 DA07 EA01 EA02 EA05 EA07 FA01 2H077 AA37 AC16 AD02 AD06 EA01 2H200 FA01 FA08 GA23 GA31 GA45 GA61 GB37 HA02 HA28 HB12 HB22 HB45 HB46 HB47 HB48 LA17 LB02 LB09 LB13 MA03 MA06 MB08

Claims (36)

[Claims] An image carrier, a charging unit for charging a surface of the image carrier, an information writing unit for forming an electrostatic latent image on the charged image carrier, and a developer for supplying a developer to the electrostatic latent image. Developing means for visualizing the electrostatic latent image, transfer means for transferring the visualized developer image to a transfer material, and developer charging which is located upstream of the charging means and charges the developer on the image carrier surface In an image forming method for forming an image by a developing and collecting method using an image forming apparatus having an amount control means, the developer remaining on the image carrier after the transfer step is charged by the developer charge amount control means. When the surface of the image bearing member is charged by the charging unit, the developer is adjusted to a proper charge amount, and the developer is a toner and carrier containing at least a binder resin, a colorant, and a release agent. A two-component developer having The average circularity in a number-based circle equivalent diameter-circularity scattergram measured by a particle image measuring device is 0.950 to 0.995, and the carrier is a magnetic material-dispersed coated carrier; 50% diameter by volume average of 15 to 6
0 μm, particle size of 2/3 or less of 50% particle size (2D / 3 ≧)
Wherein the content of the particles is 5% by volume or less, SF-1 is 100 to 130, the charging means for charging the surface of the image carrier is a charging roller having a conductive elastic layer, and a flow type particle image measuring apparatus. Image formation characterized in that the 10-point average surface roughness (Rz) of the charging roller is smaller than the circle-equivalent number average diameter D ₁ (μm) in the number-based circle-equivalent diameter-circularity scattergram measured in ( ₁ ). Method. 2. The developer remaining on the image carrier after the transfer step is charged to a normal polarity by the developer charge amount control means, and the image carrier is charged by the charging means.
2. The image forming method according to claim 1, wherein the charge amount having an absolute value smaller than the absolute value of the charge amount when the charging process is performed by the developer charge amount control unit. 3. A 10-point average surface roughness (R) of the charging roller.
The image forming method according to claim 1, wherein z) is 7 μm or less. 4. A ten-point average surface roughness (R) of the charging roller.
The image forming method according to claim 1, wherein z) is 5 μm or less. 5. The carrier according to claim 1, wherein the carrier has a core in which a metal compound is dispersed in a binder resin, and is a magnetic material-dispersed coated carrier in which the core surface is coated with a resin. The image forming method according to any one of the above. 6. The carrier contains at least two kinds of metal compound particles, the ratio of the metal compound to the binder resin is 80 to 99% by mass, and one of the metal compound particles is ferromagnetic. The non-magnetic metal compound having a higher resistance than the ferromagnetic material, and the ratio of the ferromagnetic material to the total amount of the metal compound particles is 50 to 95% by mass. The image forming method as described in the above. 7. The carrier has a specific resistance of 1 × 10 ^{8 to} 1 × 10 ¹⁶ Ω · cm, and 1000 / 4π (kA /
m) is 20 to 100 (Am ² / k)
7. The image forming method according to claim 1, wherein g) is satisfied. 8. The image forming method according to claim 6, wherein the ferromagnetic material in the carrier is magnetite, and at least one of the high-resistance metal compounds is hematite. 9. The image forming method according to claim 5, wherein the binder resin in the carrier is made of a thermosetting resin and has a crosslinked structure. 10. The image forming method according to claim 5, wherein the binder resin in the carrier is a phenol resin. 11. An image forming method according to claim 1, wherein said charging means is of a contact charging type. 12. The image forming method according to claim 1, wherein the charging unit applies an oscillating electric field. 13. An image forming method according to claim 1, wherein said information writing means is an exposure means. 14. An average circle-equivalent diameter D ₁ (μm) in a number-based circle equivalent diameter-circularity scattergram measured by a flow type particle image measuring apparatus of the toner of 2 to 10
μm and an average circularity of 0.950 to 0.99
14. The image forming method according to claim 1, wherein the circularity standard deviation is less than 0.040. 15. The image forming apparatus according to claim 1, wherein the average circularity of the toner is 0.950 to 0.995, and the standard deviation of the circularity is less than 0.035. Method. 16. The toner has an average circularity of 0.970 to 0.995 and a circularity standard deviation of 0.015 to 0.5.
The image forming method according to claim 1, wherein the number is less than 035. 17. The image forming method according to claim 1, wherein the binder resin contains 1 to 40 parts by mass per 100 parts by mass of the binder resin. 18. The image forming method according to claim 1, wherein said release agent is contained in said binder resin in an amount of 5 to 35 parts by mass per 100 parts by mass. 19. An image bearing member, charging means for charging the surface of the image bearing member, information writing means for forming an electrostatic latent image on the charged image bearing member, and supplying a developer to the electrostatic latent image. Developing means for visualizing the electrostatic latent image, transfer means for transferring the visualized developer image to a transfer material, and developer charging which is located upstream of the charging means and charges the developer on the image carrier surface An image forming method for forming an image using an image forming apparatus having an amount control means and a developing and collecting method, wherein the developer remaining on the image carrier after the transfer step is charged by the developer charge amount. The developer used in the image forming method for charging the image bearing member surface with the normal polarity by the control means and setting the proper charge amount when charging the surface of the image carrier by the charging means, wherein the developer is at least a binder resin and a coloring agent. Having toner containing toner and carrier A toner having an average circularity of 0.950 to 0.995 in a number-based circle equivalent diameter-circularity scattergram measured by a flow-type particle image measuring device of the toner, wherein the carrier is a magnetic substance A dispersion type coated carrier having a 50% diameter of 15 to 6 based on a volume average of the carrier.
0 μm, particle size of 2/3 or less of 50% particle size (2D / 3 ≧)
Wherein the content of the particles is 5% by volume or less, SF-1 is 100 to 130, the charging means for charging the surface of the image carrier is a charging roller having a conductive elastic layer, and a flow type particle image measuring apparatus. Wherein the 10-point average surface roughness (Rz) of the charging roller is smaller than the circle-equivalent number average diameter D ₁ (μm) in the number-based circle equivalent diameter-circularity scattergram measured by . 20. The developer remaining on the image carrier after the transfer step is charged to a normal polarity by the developer charge amount control means, and the image carrier is charged by the charging means. 20. The developer according to claim 19, wherein the developer is used in an image forming method in which the charge amount has an absolute value smaller than the absolute value of the charge amount when the charging process is performed by the agent charge amount control unit. 21. The charging roller according to claim 1, wherein the 10-point average surface roughness (Rz) is 7 μm or less.
21. The developer according to 9 or 20. 22. The charging roller according to claim 1, wherein the 10-point average surface roughness (Rz) is 5 μm or less.
21. The developer according to 9 or 20. 23. The carrier according to claim 19, wherein the carrier has a core in which a metal compound is dispersed in a binder resin, and is a magnetic material-dispersed coated carrier in which the core surface is coated with a resin. The developer according to any one of the above. 24. The carrier contains at least two or more kinds of metal compound particles, wherein the ratio of the metal compound to the binder resin is 80 to 99% by mass, and one of the metal compound particles is ferromagnetic. 24. The ferromagnetic material according to claim 23, wherein the other is a nonmagnetic metal compound having a higher resistance than the ferromagnetic material, and the proportion of the ferromagnetic material is 50 to 95% by mass relative to the total amount of the metal compound particles. The developer according to claim 1. 25. The carrier has a specific resistance of 1 × 10 ^{8 to} 1 × 10 ¹⁶ Ω · cm, and 1000 / 4π (kA /
m) is 20 to 100 (Am ² / k)
25. The developer according to claim 19, wherein the developer is g). 26. The ferromagnetic material of the carrier is magnetite, and at least one of the high-resistance metal compounds is hematite.
The developer according to item 1. 27. The developer according to claim 23, wherein the binder resin in the carrier is made of a thermosetting resin and has a crosslinked structure. 28. The binder according to claim 23, wherein the binder resin in the carrier is a phenol resin.
The developer according to any one of the above. 29. The developer according to claim 19, wherein said charging means is of a contact charging type. 30. The developer according to claim 19, wherein said charging means applies an oscillating electric field. 31. The developer according to claim 19, wherein said information writing means is an exposure means. 32. A circle-equivalent number average diameter D ₁ (μm) in a number-based circle equivalent diameter-circularity scattergram measured by a flow type particle image measuring device of the toner of 2 to 10
μm and an average circularity of 0.950 to 0.99
The developer according to any one of claims 19 to 31, wherein the circularity standard deviation is less than 0.040 in (5). 33. The developer according to claim 19, wherein the toner has an average circularity of 0.950 to 0.995 and a circularity standard deviation of less than 0.035. . 34. The toner has an average circularity of 0.970 to 0.995 and a standard deviation of circularity of 0.015 to 0.0.
The developer according to any one of claims 19 to 32, wherein the developer amount is less than 35. 35. The image forming method according to claim 19, wherein the releasing agent is contained in the binder resin in an amount of 1 to 40 parts by mass per 100 parts by mass. 36. The image forming method according to claim 19, wherein said releasing agent is contained in said binder resin in an amount of 5 to 35 parts by mass per 100 parts by mass.