JPH08262785A - Developer - Google Patents

Abstract

PURPOSE: To obtain a developer ensuring high image quality with high image density and low background fog and capable of preventing filming even in the case of use over a long period of time by using a carrier coated with fluororesin contg. specified electrically conductive fine powder and a toner contg. specified additives. CONSTITUTION: This developer consists of a carrier made of magnetic particles having 20-100μm average particle diameter surface-coated with fluororesin contg. electrically conductive fine powder and a toner consisting essentially of a bonding resin, an electric charge controlling agent, a colorant and additives. The electrically conductive fine powder is made chiefly of carbon black of >=pH7 having >=160ml/100g DPB oil absorption and 500-1,300m<2> /g BET specific surface area measured by nitrogen adsorption. The additives are at least inorg. fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method and having 0.05-4μm average particle diameter and 0.1-40m<2> /g BET specific surface area measured by nitrogen adsorption and hydrophobic fine silica powder surface-treated with silicone oil and having 50-350m<2> /g BET specific surface area measured by nitrogen adsorption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in black and white, color copying machines and printers.

[0002]

2. Description of the Related Art In recent years, electrophotographic apparatuses have been shifting from the purpose of office use to personal use, and have been downsized.
There is a demand for a technology that realizes maintenance-free operation. Therefore, conditions such as maintainability such as recycling of waste toner and less ozone exhaust are required.

A printing process of an electrophotographic copying machine or printer will be described. First, an image carrier (hereinafter referred to as a photoconductor) is charged to form an image. As a charging method,
Those that use the corona charger that has been used conventionally,
In recent years, there is a method of uniformly charging the surface of the photoconductor by a contact type charging method in which a conductive roller is directly pressed against the photoconductor in order to reduce the amount of ozone generated. After the photoconductor is charged, in the case of a copying machine, the copy original is irradiated with light and the reflected light is applied to the photoconductor through a lens system. Alternatively, in the case of a printer, an image signal is sent to a light emitting diode or a laser diode as an exposure light source, and a latent image is formed on the photoconductor by turning the light on and off. When a latent image (high or low surface potential) is formed on the photoconductor, the photoconductor is visualized with toner (having a diameter of about 5 μm to 15 μm) which is precharged colored powder. The toner adheres to the surface of the photoconductor according to the level of the surface potential of the photoconductor, and is electrically transferred to the copy sheet. That is, the toner is charged positively or negatively in advance, and a charge having a polarity opposite to the polarity of the toner is applied from the back surface of the copy sheet and is electrically attracted. Up to now, a corona discharger has been widely used as the charge applying method as in the charging method, but in recent years, a transfer device using a conductive roller has been put into practical use in order to reduce the ozone generation amount. At the time of transfer, not all the toner on the photoconductor is transferred to the copy sheet, but a part of the toner remains on the photoconductor. This residual toner is scraped off by a cleaning blade or the like in the cleaning section to become waste toner.

Conventionally, in the electrophotographic method, the waste toner is not reused but is discarded. From the viewpoint of global environmental protection these days,
The importance of controlling the unrestricted disposal of industrial waste is being emphasized. Toner is a consumable powder, and careless disposal leads to environmental pollution. Therefore, the reuse of this waste is an important issue.

Conventionally, there are a cascade developing method, a touch-down developing method, a jumping developing method and the like as a developing method for converting an electrostatic latent image into a visible image by an electrophotographic method. Among them,
Cascade development shown in US Pat. No. 3,105,770 is known as a developing method in which a developer is directly sprinkled on the photoreceptor. The cascade developing method is the first developing method used in a copying machine for electrophotography. Further, there is US Pat. No. 3,866,574 as a method of applying an AC bias to the developing roller to fly the one-component toner and develop the toner. According to the present invention, it is described that the AC bias applied to the developing roller is used for activating the movement of the toner, and the toner flies to the image portion, and returns to the middle in the non-image portion.

Further, as an improved technique for applying the AC bias, there is jumping development disclosed in Japanese Patent Publication No. 63-42256. In this jumping developing method, toner is carried on a toner carrier, and a rigid or elastic regulating blade is installed on the toner carrier with a minute gap from the carrier. Then, the regulation blade regulates the toner in a thin layer, conveys the toner to a developing portion, and the toner is attached to the image portion of the photoconductor by an AC bias there. The technical idea of Japanese Patent Publication No. 63-42256 differs from the above-mentioned US Pat. No. 3,866,574 in that the toner reciprocates in the image portion and the non-image portion.

In a color copying machine, a photoconductor is charged by corona discharge by a charging charger, and then a latent image of each color is applied to the photoconductor as an optical signal to form an electrostatic latent image. Develop with yellow toner to visualize the latent image.

After that, the transfer medium is brought into contact with the photoconductor, which is charged with a polarity opposite to that of the yellow toner, and the yellow toner image formed on the photoconductor is transferred. The photoconductor is destaticized after cleaning the toner remaining at the time of transfer, and finishes development and transfer of the first color toner.

After that, the same operation as that for yellow toner is repeated for magenta, cyan, etc. toners, and toner images of respective colors are superposed on a transfer material to form a color image. Then, these superposed toner images are transferred to a transfer paper charged with a polarity opposite to that of the toner, and then fixed and copying is completed.

As the color image forming method, toner images of respective colors are sequentially formed on a single photoconductor, and a transfer material wound around a transfer drum is rotated to repeatedly face the photoconductor, and sequentially formed there. A transfer drum method in which toner images of respective colors are transferred in an overlapping manner, and a plurality of image forming units are arranged side by side, and the toner images of respective colors are sequentially passed through a transfer material conveyed by a belt through the respective image forming units. A continuous superposition method of transferring and superimposing color images is common.

A color image forming apparatus using the above-mentioned transfer drum system is disclosed in Japanese Patent Laid-Open No. 1-252982. FIG. 5 shows an outline of the overall configuration of this conventional example, and the configuration and operation will be briefly described below. In FIG. 5, reference numeral 101 denotes a photoconductor, and the charger 10 faces the photoconductor.
2, developing unit 103, transfer drum 104, cleaner 1
05 is provided. The developing unit 103 includes a Y developing device 106 for forming a yellow toner image and a magenta M image.
Developing device 107, cyan C developing device 108, black Bk
The developing device 109 and the developing device 109 rotate so that each developing device sequentially faces the photoconductor 101 and is ready for development. While the transfer drum 112 and the photoconductor oppose each other during operation, they rotate in the direction of the arrow at a constant speed.

When the image forming operation is started, the photosensitive member 101 rotates in the direction of the arrow and the surface thereof is uniformly charged by the charger 102. Thereafter, the surface of the photoconductor is irradiated with a laser beam 110 modulated with a signal for forming a yellow image of the first color to form a latent image. Next, this latent image is first developed by the Y developing device 106 facing the photoconductor.
Is developed, and a yellow toner image is formed. The yellow toner image formed on the photoconductor is transferred to the transfer drum 104.
By the time it moves to the position facing the
On the outer periphery of 04, one sheet of paper as a transfer material sent from the sheet feeding section 111 is wrapped around with its front end grasped by the claw section 112, and a yellow toner image on the photoconductor is placed at a predetermined position on the sheet. Are timed so that they will meet face to face.

After the yellow toner image on the photoconductor is transferred to the sheet by the action of the transfer charger 113, the surface of the photoconductor is cleaned by the cleaner 105 to prepare the image formation of the next color. Subsequently, magenta, cyan, and black toner images are also formed in the same manner, but at that time, the developing unit 103 makes each developing device used according to the color face the photoconductor to be in a developable state. The diameter of the transfer drum is large enough so that the longest sheet of paper can be wound and the developing unit can be exchanged between images of each color.

Laser beam 110 for image formation of each color
The irradiation is performed with a timing such that the toner images of the respective colors on the photoconductor and the toner images already transferred to the sheet on the transfer drum are aligned and face each other as the toner rotates. In this way, the four color toner images are transferred to the transfer drum 10.
4 is transferred onto the paper in a superimposed manner to form a color image on the paper. After the toner images of all colors have been transferred, the sheet is peeled from the transfer drum 104 by the peeling claw 114, the toner image is fixed by the fixing unit 116 via the conveyance unit 115, and the sheet is discharged outside the apparatus.

On the other hand, as an example of a color image forming apparatus using a continuous transfer system, there is JP-A-1-250970. In this conventional example, four image forming stations each including a photoconductor, an optical scanning unit, and the like are arranged to form an image of four colors, and a sheet conveyed on a belt passes under the respective photoconductors to form a color image. The toner images are overlaid.

Furthermore, as another method of forming a color image by superposing toner images of different colors on a transfer material, the toner images of respective colors sequentially formed on the photoconductor are once superposed on the intermediate transfer material, and finally, Japanese Patent Application Laid-Open No. 2-212867 discloses a method of collectively transferring the toner images on the intermediate transfer material onto a transfer paper.

As is well known, the toner for electrostatic charge development used in these electrophotographic methods generally comprises a resin component, a coloring component consisting of a pigment or a dye and a plasticizer, a charge control agent, and if necessary, a toner. It is composed of additional components such as a magnetic material and a release agent. As the resin component, a natural or synthetic resin may be used alone or may be mixed at an appropriate time.

Then, the above additives are premixed in an appropriate ratio, heated and kneaded by hot melting, finely pulverized by an airflow type collision plate system, and finely powdered to complete a toner base.
After that, an external additive is externally added to the toner base to complete the toner.

Then, a two-component developer is completed by mixing this toner with a carrier composed of magnetic particles.

[0020]

However, in the above-mentioned structure, the cascade developing method is not good at reproducing a solid image, which is well known in the technical field of the developing method. Further, there is a problem that the device becomes large and complicated. Furthermore, US Pat.
The 574 developing device has the disadvantage that high precision is required for the device, and it is complicated and expensive. In the jumping development method, it was essential to form a very uniform thin layer on the toner carrier carrying the toner layer. In addition, this method often causes so-called sleeve ghost development, in which the history of the previous image remains in the thin toner layer on the toner carrier and the afterimage appears in the image. Further, there is a drawback that the device is complicated and the cost is high.

Therefore, the applicant of the present invention has found that the electrophotographic method of the present invention can realize the development in a small size and high performance (Japanese Patent Laid-Open No. 5-72).
890). This developing method of the electrophotographic method uses a photosensitive member containing a fixed magnet and a developer collecting electrode roller (hereinafter, referred to as an electrode roller) having a magnet facing the photosensitive member with a predetermined gap, and unnecessary development of a non-image area is performed. It is a structure for removing the agent. Therefore, this developing method faithfully reproduces a solid image, does not generate a sleeve ghost, and enables further downsizing, simplification, and cost reduction of the apparatus.

However, in order to improve the image quality by using this developing method, it is necessary to have higher performance developer characteristics.
The developer is conveyed to the developing field, which is a space with a narrow gap between the photoconductor and the electrode roller, without layer regulation. Here, the toner in the image area remains electrostatically, and the toner and carrier in the non-image area are collected by the electrode roller. At this time, with the conventional fluidity of the toner, problems such as unevenness in the solid black image portion and scattering at the character portion are likely to occur.

It is considered that this is because the regulating blade for regulating the developer in a thin layer is not used, and therefore, if the fluidity of the toner is low, the recovery from the photoconductor becomes uneven. Further, when the high-resistance carrier is separated from the photoconductor and the toner and collected, it is considered that scattering occurs due to electrostatic disturbance.

Therefore, the developer needs to have charging characteristics and flow characteristics different from those of the conventional adhesion developing method.

Conventionally, in order to enhance the fluidity of the toner, silica or the like is added as an external additive (Japanese Patent Publication No. 54-1).
No. 6219), it has been proposed to use silica fine powder which is further hydrophobized. (JP-A-46-5782, JP-A-48-47345, JP-A-48-4
7346). For example, silica fine powder which has been hydrophobized by reacting silica fine powder with an organic silicon compound such as dimethyldichlorosilane to replace the silanol group on the surface of the silica fine powder with an organic group is used. However, although the fluidity of the toner is improved by the addition of an external additive such as silica, the silica fine particles have a strong cohesive property, so that suspended matters such as silica particles increase. In addition, the floating silica has strong adhesion to the photoconductor.

When a pressing force is applied to the photoconductor during the process of forming an image, the silica suspended matter serves as a nucleus and is hit on the photoconductor to cause scratches, which triggers the adhesion of toner onto the photoconductor. The so-called toner filming occurs. Further, in the case of a carrier using magnetic particles, the magnetic particles tend to damage the photoconductor and promote the occurrence of filming. When this filming occurs,
When the charged photoconductor is exposed, the surface potential is less likely to drop, and, for example, in reversal development, an image defect occurs such that a solid black image portion is white.

Further, a suspended matter of silica adheres to a solid black image portion to generate white spot noise. The pressing force applied to the photoconductor includes the force received from the cleaning blade in the cleaning section and the abrasion force caused by the carrier attached to the photoconductor.

In the electrophotographic method using the developer according to the present invention, the intermediate transfer member is brought into contact with the photosensitive member at a constant pressure in the transfer step, and a pressing force is applied from the intermediate transfer member.

Further, in the electrophotographic method using the developer according to the present invention, the developer is first sprinkled on the entire surface of the image bearing member in the developing step and developed. Therefore, compared with the conventional method, the developer and the photoconductor are in contact with each other for a long time, and silica is more likely to adhere to the photoconductor.

Further, in the electrophotographic method using the developer according to the present invention, the waste toner is returned to the developing step and recycled. Therefore, there is a possibility that it will be used without maintenance for a longer period of time, so that silica adheres to the photoreceptor more severely.

Therefore, as compared with the conventional electrophotographic method, the toner filming is more likely to occur.

On the other hand, in order to avoid filming, it is known to use a so-called polyvinylidene fluoride powder as the friction reducing substance, for example, Japanese Patent Publication No. 48-8136.
Nos. 48-8141, 51-1130, and the like. Further, JP-A-48-47
In Japanese Patent No. 345, it is proposed to add both a friction reducing substance and an abrasive substance to the toner. According to this, it is effective for avoiding the photoconductor filming phenomenon, but when a friction reducing substance is added, low electrical resistance substances such as paper powder and ozone adducts that adhere to the surface of the photoconductor by repeated use can be obtained. There is a drawback that the removal becomes difficult to perform, and the latent image on the photoconductor is significantly impaired by the low electric resistance, especially in a high temperature and high humidity environment.

Further, JP-A-60-32060 and JP-A-59-219754 propose to add titanate type fine particles such as strontium titanate as a second external additive. However, the material described here uses mechanically pulverized material, which has an irregular shape, and although the effect of removing foreign matter on the photoreceptor can be obtained, conversely There are protrusions, the particle size distribution is broad, and a large number of large-sized particles remain, which may cause unnecessary deep scratches on the photoconductor and disturb the image.

There are also examples in which other abrasives such as alumina and titania are externally added to the toner, but these substances adversely affect the charging characteristics of the toner, resulting in a decrease in image density and an increase in background fog. I will end up.

Further, in the electrophotographic method using the developer according to the present invention, since the developer is always in contact with the entire surface of the photosensitive member, simply adding fine particles such as an abrasive and a friction reducing substance, If you continue to take documents with a low blackening rate,
There is a problem that the toner consumption is low and the selective consumption of only fine particles such as an abrasive and a friction-reducing substance increases, and the toner disappears from the toner when used for a long time, and the effect on filming is lost.

In recent years, protection of the global environment has become a big problem. In conventional copying machines, laser printers, laser plain paper fax machines, etc., toner is developed on the photoconductor in the developing process, and the toner is transferred to the paper in the transferring process. At this time, a part of the toner remains on the photoconductor. Part of the toner is scraped off in the cleaning process. The cleaned toner becomes waste toner.

The problem when recycling the waste toner is
The fluidity is lowered or the charge amount is changed by the stress that the waste toner receives in the cleaner portion, the development portion, and the transportation pipe when returning the waste toner to the development portion.

Further, at that time, toner aggregates having reduced fluidity are clogged by the developing doctor blade. Particularly, in the conventional developing method in which a blade of an elastic body or a rigid body is provided in a narrow gap or in contact with the developing sleeve to form a thin layer of toner on the developing sleeve, the structure is easily clogged. Once clogged, it is very difficult to remove.

Further, when the waste toner scraped off the photosensitive member in the cleaning step is recycled by developing again, in the conventional toner, when the waste toner and the new toner in the developing device are mixed, the charge amount distribution becomes non-uniform, The reverse polarity toner increases and the quality of the copied image deteriorates.

In this case, the resources cannot be effectively used and the global environment may be polluted. That is, recycling this waste toner and reusing resources is an urgent task from the viewpoint of global environment protection.

Further, the electrophotographic method using the developer according to the present invention has a constitution in which an intermediate transfer member is used.

In the transfer drum system, a transfer drum is used to align and superimpose toner images of different colors. The transfer drum is rotated at the same speed with respect to the photoconductor, and the timing of the leading edge of the image is adjusted to match the mutual positions of the toner images of the respective colors when a color image is formed. However, in the above configuration, since it is necessary to wind the paper around the transfer drum, the diameter of the transfer drum needs to be a certain size or more, and the structure is very complicated and high accuracy is required. Was large and expensive. Also, strong paper such as postcards and thick paper could not be used because it could not be wound around the transfer drum.

On the other hand, the continuous transfer method has an image forming position corresponding to the number of colors, and it suffices to pass the sheets of paper one after another, so such a transfer drum is unnecessary, but this method is used. In this case, a plurality of latent image forming means such as a laser optical system for forming a latent image on the photoconductor are required corresponding to the number of colors, and the structure is very complicated and expensive. Furthermore,
Since there are multiple image forming positions, relative misalignment of the image forming parts for each color, eccentricity of the rotation axis, deviation of the parallelism of each part, etc. directly affect the color misregistration, and it is difficult to stably obtain high image quality. there were. In particular, it is necessary to accurately align the positions of the latent images by the latent image forming means.
As disclosed in the publication, there is a problem that the image exposure system, which is a latent image forming means, requires considerable devise and a complicated structure.

Further, Japanese Patent Laid-Open No. 2-2 using an intermediate transfer material
In the example of 12867, a plurality of developing devices must be arranged around a single photoconductor in order to form toner images of respective colors on the same photoconductor, and the shape of the photoconductor is inevitable. Became large, and the photoreceptor became a belt shape that was difficult to handle. Also, if each developing device is replaced during maintenance, matching adjustment with the characteristics of the photoconductor is necessary,
Since it was necessary to adjust the position between the photoconductors and the developing devices when the photoconductors were replaced, it was difficult to maintain the color developing devices and the photoconductors.

However, the intermediate transfer method does not require a complicated optical system, and can be used for strong paper such as postcards and thick paper. Since the intermediate transfer belt is flexible, the transfer drum method and the continuous transfer method can be used. Compared to the method
There is an advantage that the device itself can be downsized.

However, although it is ideal that all the toner is transferred at the time of transfer, some transfer residue remains. The so-called transfer efficiency is not 100%, but is generally about 75 to 85%. The toner remaining after the transfer is scraped off by a cleaning blade or the like in the step of cleaning the photoconductor to become waste toner.

In the structure using the intermediate transfer member, the toner is transferred at least twice from the photosensitive member to the intermediate transfer member, and further from the intermediate transfer member to the image receiving paper. In the copying machine of, for example, even if the transfer efficiency is 85%, the transfer efficiency is 72% by performing the transfer twice.
Fall to. Furthermore, if the transfer efficiency is 75% in one transfer, about 56% of the toner becomes waste toner, which means that the cost of the toner and the volume of the waste toner box must be increased. Then, the device cannot be downsized.

Further, in the case of color development, since toner images of four colors are superposed on the intermediate transfer member, the toner layer becomes thick, and a pressure difference between a toner layer not present or a thin place is likely to occur. Therefore, due to the toner aggregating effect, the "blankhole" phenomenon in which a part of the image is not transferred and becomes a hole is likely to occur. Furthermore, if a material having a high toner releasing effect is used for the intermediate transfer member in order to reliably perform cleaning when the image receiving paper is jammed, hollow defects will appear remarkably and the image quality will be significantly deteriorated. Further, in the case of characters, lines, etc., edge development is performed, so that the amount of toner is increased and the toner particles agglomerate due to the pressurization, so that hollow defects become more prominent. Particularly, it appears more remarkably in an environment of high humidity and high temperature.

It is considered that the transfer efficiency is deteriorated because the low fluidity of the toner causes the voids and the low charge amount of the toner increases the amount of the opposite polarity toner, which deteriorates the transferability.

In order to improve the fluidity of the toner, conventionally, a means of adding silica or the like as an external additive has been proposed. However, although the fluidity of the toner is improved by the addition of an external additive such as silica, the silica fine particles have a strong cohesive property, so that suspended matters such as silica particles increase. Further, the floating silica is not limited to the photoconductor, and the released silica is hit on the intermediate transfer member to cause scratches, silica filming in which silica adheres to the belt, and toner filming triggered by this. .

When the amount of silica is further increased, the fluidity is improved to some extent with the addition amount, but there is a limit. Further, the amount of suspended matter of silica is further increased and the filming is further increased, which does not solve the problem.

In view of the above-mentioned problems, the present invention is a developer which realizes a high image density and a high image quality such as a low background fog in a developing method which enables further downsizing, simplification, cost reduction and recycling of the apparatus. To provide.

Another object of the present invention is to provide a developer which can prevent hollow defects and scattering at the time of transfer by an electrophotographic method using an intermediate transfer member and can obtain high transfer efficiency.

Another object of the present invention is to provide a developer capable of preventing filming of the photoconductor and the intermediate transfer member even after long-term use.

Further, even if the waste toner is recycled, the charge amount and fluidity of the developer are not deteriorated and no agglomerates are generated, the life is prolonged, the recycling development is enabled, the global environment is prevented and the resources are recycled. The purpose is to provide a developer that can be utilized.

[0056]

[Means for Solving the Problems]
Therefore, the present invention provides a fluororesin containing conductive fine powder on the surface.
It consists of coated magnetic particles with an average particle size of 20 to 100 μm.
Carrier, at least binder resin, charge control agent, coloring
And a toner composed of an external additive and a toner.
The conductive powder has at least a DBP oil absorption of 1
60 (ml / 100g) or more, BET ratio by nitrogen adsorption
Surface area is 500-1300m²/ G, PH7 or higher car
It consists of bon black and contains at least the external additive.
Is also synthesized by hydrothermal method or oxalate pyrolysis method
Average particle size 0.05-4 μm, BET ratio table by nitrogen adsorption
Area is 0.1-40m²/ G of inorganic fine particles
BE by nitrogen adsorption surface-treated with corn oil
T specific surface area is 50-350m ²/ G hydrophobic silica
It is a developer composed of fine powder.

Furthermore, the present invention is a developer in which the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles.

Further, according to the present invention, the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method is the toner 1
The developer is contained in an amount of 0.1 to 5.0 parts by weight with respect to 00 parts by weight.

Furthermore, the present invention is a developer containing 0.1 to 5.0 parts by weight of hydrophobic silica fine particles with respect to 100 parts by weight of toner.

Further, according to the present invention, a fixed magnet is contained and moved.
Image carrier, developer hopper, and surface of the image carrier
With a magnet inside at a position with a predetermined gap
It has an agent collecting electrode roller and an electrostatic latent image on the image carrier.
After being formed, the image bearing located in the developer hopper is formed.
The developer is magnetically attracted to the surface of the holder to carry the image.
The developer is carried on the surface of the body, and the image carrier is moved.
The developer recovery electrode roller, and
The carrier on the carrier and the toner in the non-image area are collected by the developer.
Development that collects with electrode roller and leaves toner on the image
And a step of visualizing the electrostatic latent image on the image carrier
The transfer process of transferring toner to transfer paper by electrostatic force, and the transfer process described above.
The toner remaining on the image carrier is partially removed from the image.
An electron having a cleaning step of removing from the carrier.
A developer used in a photographic method, wherein the developer is a conductive material.
Particle size of surface coating with fluororesin containing fine powder
A carrier composed of magnetic particles of 20 to 100 μm,
Consists of at least binder resin, charge control agent, colorant, and external additive
And a conductive powder at least,
DBP oil absorption of 160 (ml / 100g) or more, nitrogen absorption
BET specific surface area due to wearing is 500-1300m²/ G,
Made of carbon black with PH7 or above, and
The additive is at least hydrothermal method or oxalate thermal decomposition method
Average particle size of 0.05-4μm, nitrogen adsorption
BET specific surface area is 0.1-40m ²/ G
Fine particles and nitrogen treated with silicone oil
BET specific surface area by elementary adsorption is 50 ~ 350m²/ G
It is a developer composed of a certain hydrophobic silica fine powder.

Further, the present invention is a developer for use in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal developing method is visualized with toner.

Further, the present invention is a developer in which the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles.

Further, according to the present invention, the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are the toner 1
The developer is contained in an amount of 0.1 to 5.0 parts by weight with respect to 00 parts by weight.

Further, the present invention is a developer containing 0.1 to 5.0 parts by weight of hydrophobic silica fine particles with respect to 100 parts by weight of toner.

Further, according to the present invention, a fixed magnet is contained and moved.
Image carrier, developer hopper, and surface of the image carrier
With a magnet inside at a position with a predetermined gap
It has an agent collecting electrode roller and an electrostatic latent image on the image carrier.
After being formed, the image bearing located in the developer hopper is formed.
The developer is magnetically attracted to the surface of the holder to carry the image.
The developer is carried on the surface of the body, and the image carrier is moved.
The developer recovery electrode roller, and
The carrier on the carrier and the toner in the non-image area are collected by the developer.
Development that collects with electrode roller and leaves toner on the image
And a step of visualizing the electrostatic latent image on the image carrier
The transfer process of transferring toner to transfer paper by electrostatic force, and the transfer process described above.
The toner remaining on the image carrier is partially removed from the image.
A cleaning step for removing the carrier,
The toner removed in the developing step to the developing step again.
An electronic device having a toner recycling process of returning and reusing
A developer used in a photographic method, wherein the developer is a conductive material.
Particle size of surface coating with fluororesin containing fine powder
A carrier composed of magnetic particles of 20 to 100 μm,
Consists of at least binder resin, charge control agent, colorant, and external additive
And a conductive powder at least,
DBP oil absorption of 160 (ml / 100g) or more, nitrogen absorption
BET specific surface area due to wearing is 500-1300m²/ G,
Made of carbon black with PH7 or above, and
The additive is at least hydrothermal method or oxalate thermal decomposition method
Average particle size of 0.05-4μm, nitrogen adsorption
BET specific surface area is 0.1-40m ²/ G
Fine particles and nitrogen treated with silicone oil
BET specific surface area by elementary adsorption is 50 ~ 350m²/ G
It is a developer composed of a certain hydrophobic silica fine powder.

Further, the present invention is a developer for use in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal developing method is visualized with toner.

Further, the present invention is a developer in which the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles.

Further, according to the present invention, the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method is the toner 1
The developer is contained in an amount of 0.1 to 5.0 parts by weight with respect to 00 parts by weight.

Furthermore, the present invention is a developer containing 0.1 to 5.0 parts by weight of hydrophobic silica fine particles with respect to 100 parts by weight of toner.

The present invention also provides a static image formed on the image bearing member.
A developing step for developing the latent electrostatic image with toner;
Containing carbon black abutting the image bearing member on the image bearing member.
Endless intermediate transfer using polycarbonate as a basic component
Primary transfer to the body and multiple steps of the primary transfer
The step of operating to form a transferred toner overlapping image,
The transfer toner overlapping image formed on the inter-transfer member
Or a step of performing a secondary transfer at once to the image receiving paper conveyed from
A developer used in an electrophotographic method composed of
The developer uses a fluororesin containing conductive fine powder on its surface.
Made of magnetic particles having an average particle size of 20 to 100 μm
Carrier and at least binder resin, charge control agent, coloring
And a toner containing an external additive,
At least the powder has a DBP oil absorption of 160 (ml / 10
0 g) or more, the BET specific surface area due to nitrogen adsorption is 500 to
1300m²/ G, from PH7 or higher carbon black
And the external additive is at least a hydrothermal method or
Average particle size of 0.05 synthesized by oxalate pyrolysis
~ 4 μm, BET specific surface area due to nitrogen adsorption is 0.1-4
0m ²/ G of inorganic fine particles and silicone oil
BET specific surface area by adsorption of nitrogen is 50
~ 350m²/ G of hydrophobic silica fine powder
It is a developer.

Further, the present invention is a developer used in an electrophotographic method, which is an intermediate transfer member having a surface treated with a fluororesin.

Further, the present invention is a developer for use in an electrophotographic method in which an electrostatic latent image formed on an image bearing member by a reversal developing method is visualized with toner.

Further, the present invention is a developer in which the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles.

Further, in the present invention, the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are
The developer is contained in an amount of 0.1 to 5.0 parts by weight with respect to 00 parts by weight.

Furthermore, the present invention is a developer containing 0.1 to 5.0 parts by weight of hydrophobic silica fine particles with respect to 100 parts by weight of toner.

Further, according to the present invention, a fixed magnet is contained and moved.
Image carrier, developer hopper, and surface of the image carrier
With a magnet inside at a position with a predetermined gap
It has an agent collecting electrode roller and an electrostatic latent image on the image carrier.
After being formed, the image bearing located in the developer hopper is formed.
The developer is magnetically attracted to the surface of the holder to carry the image.
The developer is carried on the surface of the body, and the image carrier is moved.
The developer recovery electrode roller, and
The carrier on the carrier and the toner in the non-image area are collected by the developer.
Development that collects with electrode roller and leaves toner on the image
And a step of visualizing the electrostatic latent image on the image carrier
The carbon black in which the toner image is brought into contact with the image carrier is
Endless medium containing polycarbonate as a basic component
Primary transfer to the inter-transfer member, and the developing process and the primary transfer are performed.
The process is operated multiple times to form the transferred toner overlap image,
The above-mentioned transfer toner overlapping image formed on the intermediate transfer member is fed.
Transfer process to perform secondary transfer collectively to the image receiving paper conveyed from the side
A developer used in the electrophotographic method, which is composed of
The developer is a fluororesin containing conductive fine powder.
Magnetic particles having an average particle size of 20 to 100 μm
Carrier consisting of at least binder resin and charge control
The toner consists of an agent, a colorant, and an external additive.
The conductive powder has at least a DBP oil absorption of 160 (m
1/100 g) or more, the BET specific surface area due to nitrogen adsorption is
500-1300m²/ G, PH7 or higher carbon bra
And the external additive is at least hydrothermal
Average particle size synthesized by the method or oxalate pyrolysis method
0.05 ~ 4μm, BET specific surface area due to nitrogen adsorption
0.1-40m ²/ G inorganic fine particles and silicone
BET ratio table by nitrogen adsorption surface-treated with oil
Area is 50-350m²/ G of hydrophobic silica fine powder
Is a developer consisting of.

Further, the present invention is a developer used in an electrophotographic method, which is an intermediate transfer member surface-treated with a fluororesin.

Further, the present invention is a developer for use in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal development method is visualized with toner.

Furthermore, the present invention is a developer in which the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles.

Furthermore, according to the present invention, the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are used as the toner 1.
The developer is contained in an amount of 0.1 to 5.0 parts by weight with respect to 00 parts by weight.

Furthermore, the present invention is a developer containing 0.1 to 5.0 parts by weight of hydrophobic silica fine particles with respect to 100 parts by weight of toner.

[0082]

According to the present invention, by using the inorganic fine particles, which are synthesized by the hydrothermal method or the oxalic acid method and have a spherical shape, as an external additive having the above-mentioned constitution, the photosensitive member is exposed without causing any scratch. It becomes possible to remove the foreign matter attached to the body.

The inorganic fine particles are separated from the toner and independently adhere to the photoconductor, are supplied to the cleaning section without being transferred to the transfer material in the transfer step, and adhere to the cleaning blade. By attaching the inorganic fine particles to the cleaning blade, it is possible to remove the foreign matter attached to the photoreceptor.

At this time, the inorganic fine particles synthesized by the hydrothermal method or the oxalic acid method have an average particle diameter of 0.05 to 4 μm and a BET specific surface area due to nitrogen adsorption of 0.1 to 40 m ² / g.
Preferably B having an average particle size of 0.1 to 3 μm and nitrogen adsorption
The ET specific surface area is 1.0 to ²⁰ m ² / g, more preferably the average particle size is 0.5 to ² μm, and the BET specific surface area by nitrogen adsorption is ² to 15 m ² / g.

Furthermore, the inorganic fine particles synthesized by the hydrothermal method and the oxalic acid method have the opposite polarity charging property to the base particles of the toner before the external addition treatment, and the charge amount is an absolute value by the blow-off measurement method. Of 2 to 20 μC / g is used, and further, inorganic fine particles having a quiet density of 0.2 to 1.2 g / cm ³ are used, and the true specific gravity is 5.0 to 8.
By using the inorganic fine particles of 5 g / cm ³ ,
The dispersibility of the inorganic fine particles is further improved, the inorganic fine particles are uniformly attached to the base particles of the toner, and effectively act on the filming.

If the average particle size is less than 0.05 μm, the dispersibility of the inorganic fine particles is deteriorated and the aggregates are increased, resulting in image defects. Also, the BET specific surface area due to nitrogen adsorption is 40 m ² /
Similarly, when it is more than g, the dispersibility of the inorganic fine particles is deteriorated, aggregates increase, and image defects occur. Static bulk density 0.2g /
If it is less than ³ cm ^3, the cohesiveness of the inorganic fine particles is increased and the dispersion is deteriorated.

When the average particle diameter is 4 μm or more, the toner particles are separated from the mother particles of the toner to give unnecessary damage to the photoreceptor. When the BET specific surface area due to nitrogen adsorption is 0.1 m ² / g or less, coarse particles are increased and the coarse particles are separated from the mother particles of the toner to give unnecessary damage to the photoreceptor. When the static bulk density is 1.2 g / cm ³ or more, the dispersibility is deteriorated and the number of scratches on the photoreceptor is increased.

The absolute value of the charge amount of the inorganic fine particles is 2 μC / g
In the following cases, the separation of the inorganic fine particles from the base particles of the toner becomes severe, and the selective consumption proceeds. When the charge amount of the inorganic fine particles is 20 μC / g or more, the chargeability of the toner itself is affected and the background fog occurs.

If the true specific gravity is 5.0 g / cm ³ or less, the dispersibility deteriorates. When the true specific gravity is 8.5 g / cm ³ or more, selective consumption proceeds, and stable images cannot be obtained for a long period of time.

Further, when the hydrophobic silica surface-treated with silicone oil represented by the general formula (Formula 1) is used as an external additive, a toner having a high negative chargeability can be obtained,
It is possible to obtain high-quality images with little background fog and sharp characters.

This is because the silanol groups, which are hydrophilic groups, present on the surface of the silica fine particles are completely covered, and the siloxane groups are present on the surface, so that high negative chargeability can be obtained.

However, the silica material itself has a strong secondary agglomeration property, and many agglomerates of silica are present, so that the fluidity is lowered and white spot noise due to the silica soul is likely to occur.

Therefore, the BET specific surface area due to nitrogen adsorption is 5
It was found that by adding 0 to 350 m ² / g and inorganic fine particles synthesized by the hydrothermal method or the oxalic acid method of the present invention and externally treating, the generation of silica aggregates can be significantly suppressed. The cause is unknown, but it is speculated that a shearing force is applied to the silica during the external addition process to loosen the aggregates. It was also found that this has the effect of improving the fluidity of the toner and also enhancing the charging property.

BET specific surface area due to nitrogen adsorption is 50 m ²
If it is less than / g, the fluidity of the toner will decrease. When the BET specific surface area due to nitrogen adsorption is 350 m ² / g or more, the aggregating property becomes strong, and the formation of aggregates cannot be suppressed even when mixed with the inorganic fine particles.

[0095]

Embedded image

At this time, the polymerization degree n is preferably 10 to 100. When the polymerization degree n is 10 or less, it is difficult to obtain high negative chargeability. If the degree of polymerization n is 100 or more, the surface treatment becomes uneven.

Further, the developer of the present invention is used for two-component development. In the conventional carrier, the surface of magnetic particles such as ferrite is coated with a resin to control the charging property of the toner. In order to charge the toner with a negative charging property, a silicone-based resin coating material is often used. However, the silicon-based resin has a drawback that the toner is apt to be fused with the carrier during long-term use, and that the carrier itself is easily charged up and the image density is lowered during long-term use.

Generation of spent can be suppressed by using a fluorine-based resin coating material for the spent.

However, since the carrier itself has a strong negative charging property, when it is used as a negative charging toner, it is difficult to obtain a highly charged toner, and the charge amount distribution becomes non-uniform, and the background fog increases. Further, since the strength of the resin film is weak, the film peels off and deteriorates during long-term use.

However, when the DBP oil absorption of the present invention is 160 (m
1/100 g) or more, a BET specific surface area due to nitrogen adsorption of 500 to 1300 m ² / g, and a fluororesin-coated magnetic particle containing carbon black of PH7 or more is used as a carrier to increase the strength of the film and charge up. It was found that the above-mentioned phenomenon was suppressed, and that the chargeability was uniform.

This is because the strength of the resin film is increased due to the thickening effect of the inclusion of carbon black, and peeling of the film is suppressed even during long-term use.

Further, since the structure has a long oil absorption and a long structure, it is presumed that charge accumulation can be prevented and charge-up can be prevented.

Further, the mechanism by which the chargeability of the toner can be negatively and uniformly controlled is unknown, but it is presumed as follows.
By combining with a highly flowable and highly chargeable toner containing highly chargeable silica uniformly crushed by inorganic fine particles synthesized by a hydrothermal method or oxalic acid method, silica present on the toner surface Since they are arranged uniformly, if unnecessary excessive electric charge is accumulated in silica in the toner, the contact with the carrier becomes more uniform, and the unnecessary electric charge flows to the carrier side, and the charging property becomes uniform. I guess.

The DBP oil absorption of the conductive powder is 160 (ml
/ 100 g) or less, charge-up cannot be prevented. When the BET specific surface area is 1300 or more, the dispersion when contained in the resin is deteriorated and the chargeability becomes nonuniform. B
When the ET specific surface area is 500 or less, the charging property becomes non-uniform.
When the pH is 7 or less, the negative charging property becomes strong and high charging property cannot be obtained.

The average particle size of the carrier is 20 to 100 μm.
m is preferred. When it is 20 μm or less, the mixing property with the toner is lowered and the toner scattering is increased. On the other hand, when it is 100 μm or more, sweep marks are likely to occur on a solid black image.

In the electrophotographic method using the developer according to the present invention, an image carrier containing a fixed magnet is used, and the developer is sprinkled and magnetically adhered to the image carrier on which an electrostatic latent image is formed.
The carrier is carried to the electrode roller portion, an AC bias is applied to the electrode roller, and the carrier of the image bearing member and the non-image portion toner are removed by electrostatic force and magnetic force.

That is, the electrophotographic method using the developer according to the present invention is a cascade development method in which a magnet is installed inside the image bearing member and an AC voltage is applied to the electrodes to further reduce the size and improve the performance.

In the electrophotographic method using the developer according to the present invention, the development is almost completed when the developer is first sprinkled on the image carrier. The electrode roller part circulates the developer in the developer hopper and at the same time collects the toner in the non-image part of the electrostatic latent image. That is, it is the image carrier that carries and carries the developer from the developer hopper to the developing section. The bare surface of the electrode roller, which does not carry the developer layer, faces the image carrier. The electrode roller and the image carrier rotate in opposite directions.

Further, in the electrophotographic method using the developer according to the present invention, waste toner is recycled. In the developing method of the present invention, since the electrode roller and the image carrier rotate in opposite directions, even if the fluidity is lowered and the agglomerated toner is conveyed to the collecting section, it can be immediately removed from the collecting section. is there.

In the developing process and the waste toner recycling process having a simple structure, a stable and high-quality image cannot be obtained unless the developer is kept to have higher fluidity and higher charging property than ever before.

Therefore, toner externally added with silica surface-treated with silicone oil which is mixed with inorganic fine particles synthesized by hydrothermal method or oxalic acid method and uniformly crushed, and fluorocarbon resin coating containing carbon black By using the magnetic particles as a carrier, a developer having a high negative chargeability and a uniform charge amount distribution can be obtained, and a high-quality image with sharp characters can be obtained.

Further, when the toner attached to the photoconductor is separated and collected, the carrier has a uniform charge distribution, so that the carrier remains on the photoconductor or the toner necessary for the development is collected by being collected. Never be done.

Further, the electrophotographic method using the developer according to the present invention has a very strict construction against toner filming of the photoconductor.

Generation of silica aggregates can be greatly suppressed by externally adding silica which is uniformly crushed by mixing with inorganic fine particles synthesized by hydrothermal method or oxalic acid method.

However, it is difficult to suppress the occurrence of toner filming on the photosensitive member only by eliminating the silica agglomerates and obtaining a uniform dispersion. Since silica is added to the toner by a mixing process, it is impossible to completely suppress the free silica, so that it is inevitably attached to the photoreceptor. The silica is driven into the photoconductor by some kind of stress, and toner filming occurs using it as a trigger. The stress is a cleaning blade or the like. In particular, in the electrophotographic method according to the present invention, since the developer is attached to the entire surface of the photoconductor at the time of development, the developer and the photoconductor are always in contact with the entire surface as compared with the conventional developing method. This is a configuration in which minging occurs more easily. Furthermore, when it comes to recycling waste toner,
The latitude for filming becomes narrower.

However, by using as the external additive inorganic fine particles spherical in shape synthesized by the hydrothermal method or the oxalic acid method, the particles adhered to the photoconductor without causing unnecessary scratches on the photoconductor. It becomes possible to remove foreign matter.

The fine particles synthesized by the hydrothermal method or the oxalic acid method give spherical particles having less aggregation, a narrow particle size distribution and good fluidity. Therefore, when externally added and mixed to the toner, the dispersibility is good and the toner uniformly adheres to the toner. Further, since the shape is spherical, the photoreceptor is not scratched unnecessarily.

By separating the inorganic fine particles from the toner and adhering to the photosensitive member alone and supplying them to the cleaning blade, the foreign matters adhering to the photosensitive member can be removed.

If the inorganic fine particles have the opposite polarity charging property, the inorganic fine particles are supplied to the cleaning blade portion without being attached by transfer, which is a great effect on filming.

Further, by using the inorganic fine particles synthesized by the hydrothermal method or the oxalic acid method, the unevenness of halftone and solid black images in the electrophotographic method using the developer according to the present invention is reduced, and more uniform. It turned out that sex can be obtained. This is because the toner adheres to the entire surface of the photoconductor during development, so if there is non-uniform aggregation of the toner particles, it appears as unevenness in the image, but the inorganic fine particles act as a buffer to alleviate the non-uniform aggregation of the toner particles. Is considered to be fulfilling.

When the average particle size is less than 0.05 μm, the dispersibility of the inorganic fine particles is deteriorated and the aggregates are increased, resulting in image defects. Also, the BET specific surface area due to nitrogen adsorption is 40 m ² /
Similarly, when it is more than g, the dispersibility of the inorganic fine particles is deteriorated, aggregates increase, and image defects occur. Static bulk density 0.2g /
If it is less than ³ cm ^3, the cohesiveness of the inorganic fine particles is increased and the dispersion is deteriorated.

When the average particle diameter is 4 μm or more, the toner is separated from the base particles of the toner to give unnecessary damage to the photoreceptor. When the BET specific surface area due to nitrogen adsorption is 0.1 m ² / g or less, coarse particles are increased and the coarse particles are separated from the mother particles of the toner to give unnecessary damage to the photoreceptor. When the static bulk density is 1.2 g / cm ³ or more, the dispersibility is deteriorated and the number of scratches on the photoreceptor is increased.

The absolute value of the charge amount of the inorganic fine particles is 2 μC / g
In the following cases, the separation of the inorganic fine particles from the base particles of the toner becomes severe, and the selective consumption proceeds. When the charge amount of the inorganic fine particles is 20 μC / g or more, the chargeability of the toner itself is affected and the background fog occurs.

If the true specific gravity is 5.0 g / cm ³ or less, the dispersibility deteriorates. When the true specific gravity is 8.5 g / cm ³ or more, selective consumption proceeds, and stable images cannot be obtained for a long period of time.

Further, in the electrophotographic method using the developer according to the present invention, since the developer is adhered to the entire surface of the photoreceptor during development, the inorganic fine particles added to the toner are released from the toner and selectively selected on the photoreceptor without restriction. If adhered to, the consumption of only the inorganic fine particles will proceed. If a document with a low blackening rate is continuously taken, the consumption of only inorganic fine particles will increase, and the effect on filming will gradually decrease. In addition, the inorganic fine particles are excessively present in the waste toner, and when the waste toner is recycled, the charging property and the fluidity are adversely affected.

However, by adding the inorganic fine particles of the present invention, the inorganic fine particles are appropriately held by the toner base particles, so that the toner is always in contact with the entire surface of the photosensitive member in the electrophotographic method of the present invention. Even if there is a document with a low blackening rate, the selective and unlimited consumption of only the inorganic fine particles can be suppressed.

As a result, the inorganic fine particles are present as long as the toner remains, and the effect on filming is maintained even if the waste toner is recycled and used for a long time.

In the electrophotographic method using the developer according to the present invention, the intermediate transfer member is used as the transfer means. The toner image is transferred from the image carrier to the intermediate transfer belt, retransferred from the intermediate transfer belt to the image receiving paper, and transferred twice. Since these transfer operations are performed by bringing the transfer member into contact with the transfer target member by electrostatic force and pressure, if the fluidity of the toner is lowered or the charging property is lowered, defective transfer or hollow defects are likely to occur.

By using the developer of the present invention, the toner retains a high fluidity and a uniform charge amount distribution is obtained, so that the transfer efficiency is not lowered and the voids can be prevented. A clear image with no splattering can be obtained.

Toner filming also occurs on the intermediate transfer member. If the endless intermediate transfer member containing a polycarbonate containing carbon black whose surface is treated with a fluorine resin as a basic component is excessively polished, the treated film on the surface is excessively peeled off. Further, because of the contact transfer, all the inorganic fine particles added to the toner are transferred and do not remain on the photoconductor, so that the filming removal effect of the photoconductor may not be obtained. However, since the inorganic fine particles of the present invention have an opposite charging property to the toner, some of them remain on the photoconductor. Further, due to the spherical surface shape and the sharp particle size distribution, it is possible to uniformly remove the adhered filming without damaging the surface of the intermediate transfer member.

Further, in the electrophotographic method using the developer according to the present invention, an image carrier containing a fixed magnet is used, and the developer is sprinkled magnetically on the image carrier on which an electrostatic latent image has been formed to magnetically adhere to the electrode. A developing structure in which the carrier is carried to the roller unit, an AC bias is applied to the electrode roller, and the carrier of the image carrier and the toner in the non-image area are removed by electrostatic force and magnetic force, and an intermediate transfer member is used.

Therefore, at the time of development, it is necessary to separate the toner adhering to the image area from the carrier and collect only the carrier. At this time, if a low-fluidity toner or a developer having a poor charging property is used, not only unevenness is caused in the image area, but also voids occur more markedly at the time of transfer, leading to image defects and lower transfer efficiency.

When filming occurs on the photosensitive member,
The pressure on the periphery changes at the convex portion, and transfer failure occurs even in a region where the photoconductor filming has not occurred.

Then, a toner externally added with a silica surface-treated with silicone oil which is mixed with inorganic fine particles synthesized by a hydrothermal method or an oxalic acid method and uniformly crushed, and a fluororesin coat containing carbon black are used. By using the magnetic particles as a carrier, a developer having a high negative chargeability and a uniform charge amount distribution can be obtained, and a high-quality image with sharp characters can be obtained.

When the carrier attached to the photoconductor is collected by separating the toner, since the carrier has a uniform charge distribution, the carrier remains on the photoconductor or the toner necessary for development is collected by being collected. Never be done.

The inorganic fine particles added to the toner can prevent filming on the photosensitive member and the intermediate transfer member.

As described above, according to the electrophotographic method using the developer of the present invention, a toner capable of maintaining high fluidity and high chargeability by a developing method capable of further downsizing, simplification and cost reduction of the apparatus is obtained. By using it, an image with high image density and low ground fog can be obtained.

Further, even if the waste toner is recycled, the fluidity and the amount of charge are not lowered, and the toner filming on the photoconductor can be prevented. Therefore, the waste toner is not required to be recycled and the recycling is effective for the global environment. It is possible to provide a developer capable of preventing pollution and reusing resources.

In the transfer process using the intermediate transfer member, when toner such as characters and lines is concentrated,
It is possible to provide a developer in which agglomeration of toner particles does not easily occur even when transferred with a predetermined pressing force, a clear image with no voids is obtained, and transfer efficiency does not decrease even when transferred twice.

[0140]

EXAMPLES The developer according to the present invention is manufactured by the following method.

The toner is mixed, kneaded, pulverized, externally added, and if necessary classified. The mixing process is a process of uniformly dispersing the binder resin, the charge control agent, the colorant, and other internal additives such as a release agent, which are added as necessary, with a mixer equipped with a stirring blade. Known processing methods such as Kawada Manufacturing Co., Ltd., Henschel mixer (Mitsui Miike Kogyo Co., Ltd.), PS mixer (Kanko Pantech Co., Ltd.) and Rödege mixer are used.

In the kneading process, the mixed material is heated to disperse the internal additive in the binder resin by shearing force. The kneading at this time can be performed using a known heating kneader. As the heating and kneading machine, use a device (for example, PCM30, manufactured by Ikegai Tekko Co., Ltd.) that heats a kneaded product such as a three-roll type, a single-screw type, a twin-screw type, or a Banbury mixer type and applies a shearing force to the kneaded substance. Can be done. The mass obtained by the kneading treatment is roughly crushed by a cutter mill or the like, and then finely pulverized by a jet mill pulverization (for example, IDS pulverizer, Nippon Pneumatic Mfg. Co., Ltd.) or the like. It is cut to obtain the desired particle size distribution.

Mechanical pulverization and classification are also possible. For example, there are methods such as a kryptron crusher (Kawasaki Heavy Industries) and a turbo mill (Turbo industry) in which toner is charged into a minute gap between a fixed stator and a rotating roller and crushed. Known methods are used in both cases.

External additives are externally added to the toner base particles thus obtained. External processing is Henschel mixer,
A known method such as a super mixer is used.

The carrier is prepared by coating the surface of the ferrite fine particles with a resin. Ferrite is Cu, Zn, M
Fine particles mixed with n and the like are used. Then, the surface is coated with a fluororesin containing carbon black. Known methods such as spraying and dipping are used.

The binder resin of the toner according to the present invention is a vinyl polymer obtained by polymerizing or copolymerizing vinyl monomers.
Examples of the monomer styrene constituting the binder resin include styrene, α-methylstyrene, styrene such as P-chlorostyrene and its substitution products, and acrylic acid alkyl ester such as acrylic acid, methyl acrylate, and the like.
Ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, isobutyl acrylate, hexyl acrylate, alkyl methacrylates include, for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, methacrylic acid. Examples include monocarboxylic acids having a double bond such as isobutyl, dodecyl methacrylate, and hexyl methacrylate, and substituted products thereof.

As a method for producing these copolymers, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization are adopted.

The copolymer used in the toner according to the present invention preferably contains a styrene-based component as a 50 to 95% by weight component. If the proportion of styrene is less than 50% by weight, the melting properties of the toner will be poor, the fixability will be insufficient, and the pulverizability will be poor.

The toner according to the present invention contains the binder resin as a main component as described above, but other known polymers or copolymers may be used as necessary in addition to the main component. For example, there are polyester resin, epoxy resin, polyurethane resin, and the like.

Inorganic fine particles are added to the developer according to the present invention.
In addition, it is synthesized by the hydrothermal method or the oxalic acid method.
As the material, CaSiO₃, LaCrO₃, AlP
O_Four, NbP₃O_Four, LaFeO₃, LiNbO₃, SrT
iO₃, BaTiO₃, CaTiO ₃, PbTiO₃, Fe
TiO₃, SrZrO₃, BaZrO₃, CaZrO₃, P
bZrO₃, MnSiO₃, MgSiO₃, MoO₂, Sn
O₂, ZnO₂, MgO₂, NiO, V₂O_Five, Nb₂O_Five,
WO₂, Nb₂O₃-TiO₂, Ta₂O_Five-TiO₂, V₂O
_Five-ZnO₂Etc. Preferably SrTiO₃,
BaTiO₃, MgTiO₃, AlTiO₃, CaTi
O₃, PbTiO₃, FeTiO₃, SrZrO₃, BaZ
rO₃, MgZrO₃, AlZrO₃, CaZrO₃, Pb
ZrO₃, MnSiO₃, CaSiO₃, MgSiO₃so,
More preferably SrTiO₃, BaTiO₃, MgTiO
₃, AlTiO₃, CaTiO₃, PbTiO₃, FeTi
O₃Titanate such as SrZrO₃, BaZrO₃, M
gZrO₃, AlZrO₃, CaZrO₃, PbZrO₃etc
Is a zirconate salt of.

As the method for synthesizing fine particles under the hydrothermal conditions, there are hydrothermal oxidation method, hydrothermal precipitation method, hydrothermal synthesis method, hydrothermal dispersion method, hydrothermal crystallization method, hydrothermal hydrolysis method and water. There are a heat attritor mixing method and a hydrothermal mechanochemical method. Preferred are a hydrothermal oxidation method, a hydrothermal precipitation method, a hydrothermal synthesis method, a hydrothermal dispersion method and a hydrothermal hydrolysis method.

In the oxalate thermal decomposition method, for example, in the case of barium titanate fine particles, TiCl ₄ (aq) and BaCl ₂ ·.
A mixed solution A of 2H ₂ O (maintained at 30 ° or less) was prepared, and oxalic acid (COOH) ₂ · 2H ₂ O was maintained at 80 °.
The mixed solution A is dropped into the aqueous solution to form BaTiO (C ₂ O ₄ ).
4H ₂ O is obtained. Fine particles of BaTiO ₃ are obtained by heating this to 600 ° or more.

The fine particles synthesized by this method are spherical particles having less aggregation, a narrow particle size distribution and good fluidity. Therefore, when externally added and mixed to the toner, the dispersibility is good and the toner uniformly adheres to the toner. Further, since the shape is spherical, filming can be removed without giving unnecessary damage to the photoconductor.

Inorganic materials such as titanate and fine particles of zirconate are charged oppositely to the organic material of the toner binder resin of the present invention described above. Further, for example, with respect to the positive chargeability, a high positive chargeability can be obtained by surface treatment of a titanium coupling agent, a coupling agent having a nitrogen group, or an organic material having a nitrogen group.

The addition amount of the inorganic fine particles is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the toner. When the amount is 0.1 parts by weight or less, the effect on filming is small,
If it is 5.0 parts by weight or more, the cohesiveness becomes strong, and the photoreceptor is uselessly scratched.

Negatively charged hydrophobic silica fine particles surface-treated with silicone oil are added to the developer according to the present invention. The silica fine particles are preferably silica fine particles produced by vapor phase oxidation of a silicic acid halogen compound, and for example, those utilizing a thermal decomposition oxidation reaction in oxyhydrogen flame of silicon tetrachloride gas. The general formula of the reaction is shown in (Chemical Formula 2).

[0157]

Embedded image

The preferred silicone oil for surface-treating the silica fine particles used in the present invention is polydimethyl silicone oil, and in addition, alkyl-modified silicone oil, fluorine-modified silicone oil and the like are preferable.

As the surface treatment method, a known technique is used, and a method of mixing using a mixer such as a Henschel mixer or a method of spraying silicone oil may be used.

The amount of silica added is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the toner. In order to prevent the aggregation of toner particles, it is necessary to add 0.1 parts by weight or more.
On the contrary, if it is 5.0 parts by weight or more, the amount of floating silica increases.

If necessary, the toner according to the present invention may be mixed with a suitable pigment or dye for the purpose of controlling coloring and charge. Examples of such pigments or dyes include carbon black, iron black, graphite, nigrosine, metal complexes of azo dyes, phthalocyanine blue, DuPont oil red, aniline blue, benzidine yellow, rose bengal, and mixtures thereof, etc., and charge amount, The amount required for coloring is blended.

Further, the toner according to the present invention may further contain a release agent such as WAX if necessary.

Next, an electrophotographic method using the developer according to the present invention will be described with reference to the drawings. The present invention is not limited to this.

(Embodiment 1) FIG. 1 is a sectional view of an electrophotographic apparatus according to an embodiment of an electrophotographic method using a developer according to the present invention. Reference numeral 11 denotes an organic photoreceptor, and a charge generation layer in which a charge generation substance of τ type metal-free phthalocyanine (manufactured by Toyo Ink) is dispersed in polyvinyl butyral resin (Elec BL-1 manufactured by Sekisui Chemical Co., Ltd.) on an aluminum conductive support, Polycarbonate resin (Z-200 manufactured by Mitsubishi Gas Chemical) and 1,1
The charge transport layers containing -bis (P-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene (T-405 manufactured by Annan) are sequentially laminated. 20
2 is a non-rotating magnet that is fixed coaxially with the photoconductor 11;
03 is a corona charger for negatively charging the photoconductor, 20
Reference numeral 4 denotes a grid electrode for controlling the charging potential of the photoconductor, 205
Is the signal light.

The developing device for visualizing the latent image after exposure is a developer 207 comprising a toner 207A and a carrier 207B, 206 a developer hopper for supplying the developer 207 to the surface of the photoreceptor 11, and 208. Is a non-magnetic electrode roller set with a gap from the photoconductor 11; 209 is a non-rotating magnet installed inside the electrode roller 208;
Is a high-voltage power supply for applying a voltage to the electrode roller 208, 211
Is a scraper made of polyphenylene sulfide that scrapes off the developer on the electrode roller.
No. 08 collects excess developer in the non-image area.

Reference numeral 212 is a damper for smoothing the flow of the developer in the developer hopper and for preventing the developer from being crushed by its own weight to cause clogging between the photoconductor and the electrode roller. .

Reference numeral 213 denotes a transfer roller for transferring the toner image on the photoconductor to the paper, which is set so as to come into contact with the photoconductor 11. The transfer roller is an elastic roller in which a conductive elastic member is provided around a shaft made of a conductive metal. Photoconductor 11
The pressing force for each transfer roller 213 (about 216 m
m) 0 to 2000 g, preferably 500 to 1000 g. This was measured from the product of the spring coefficient and the amount of contraction of the spring for pressing the transfer roller 213 against the photoconductor 11. The contact width with the photoconductor 11 is about 0.5 mm to 5 mm. The rubber hardness of the transfer roller 213 is 80 degrees or less, preferably 30 to 40 degrees by the Asker C measurement method (measurement using a block piece instead of the roller shape). In the present invention, the elastic roller 213 has a conductive urethane elastomer in which a foaming lithium salt is internally added around a shaft having a diameter of 6 mm and has a resistance value of 10 ⁷ Ω (an electrode is provided on the shaft and the surface, and 500 V is applied to both of them).
Applied) was used. The entire outer diameter of the transfer roller 213 was 16.4 mm, and the hardness of Asker C was 40 degrees. Transfer roller 213 to photoconductor 11
The shaft of 13 was brought into contact by pressing it with a metal spring. The pressing force was about 1000 g. The present invention is not limited to this material.

For the elastic body of the roller, CR rubber, NBR, S
Examples thereof include i rubber, fluororubber, and urethane foam.
Preferred is a urethane foam. And as a conductivity imparting agent for imparting conductivity, carbon black,
There are lithium salts such as Li ₂ O, preferably lithium salts such as Li ₂ O.

Reference numeral 214 is a thrust guide made of a conductive member for introducing the transfer paper to the transfer roller 213, and 215 is a conveyance guide in which the surface of the conductive member is covered with an insulating material. The plunge guide 214 and the transport guide 215 are grounded directly or through a resistor. 216 is a transfer paper, 217 is a transfer roller 2
13 is a voltage generating power source for applying a voltage to 13.

Reference numeral 218 is a cleaning blade for scraping off the residual toner after transfer, 219 is a cleaning box for storing waste toner, and 223 is waste toner.

Examples of the cleaning means include a fur brush to which a bias is applied, a conductive metal roller, an elastic urethane blade and the like. An elastic urethane blade is preferable.

The magnetic flux density on the surface of the photoconductor 11 is 600 Gs.
Is. The magnetic force inside the electrode roller was strengthened to improve transportability. The magnetic pole angle θ of the magnet 202 shown in the figure was set to 15 degrees. The photoconductor 11 had a diameter of 30 mm and was rotated at a peripheral speed of 60 mm / s in the direction of the arrow in the figure for use.
The diameter of the electrode roller 208 is 16 mm, and the peripheral speed is 40 mm /
In s, the photoconductor 11 was rotated in the direction opposite to the traveling direction (the direction of the arrow in the figure). Photoconductor 11 and electrode roller 208
The gap between and was set to 300 μm.

The corona charger 203 (applied voltage −4.5 kV, grid 204 voltage −500 V) was used as the photoconductor 11.
Then, it was charged to -500V. The photoconductor 11 was irradiated with a laser beam 205 to form an electrostatic latent image. At this time, the exposure potential of the photoconductor 11 was −90V. The developer 207 was attached to the surface of the photoconductor 11 by a magnet in the developer hopper 206. Next, the photoconductor 11 is connected to the electrode roller 208.
I passed in front of. When the photoconductor 11 passes through the uncharged area, the AC high voltage power supply 210 is applied to the electrode roller 208,
AC voltage of 750V 0-p (peak-to-peak 1.5kV) superposed with 0V DC voltage (frequency 1kHz)
Was applied. After that, when the photoconductor 11 charged with −500 V and having the electrostatic latent image written thereon is passed, the electrode roller 208 is used.
Is a 750V 0-p (peak-to-peak 1.
An alternating voltage (frequency: 1 kHz) of 5 kV) was applied. Then, the developer attached to the charged portion of the photoconductor 11 is collected by the electrode roller 208, and a negative-positive inverted toner image of only the image portion remains on the photoconductor 11. The developer attached to the electrode roller 208 rotating in the direction of the arrow is removed by the scraper 21.
It was scraped off by 1, returned to the inside of the developer hopper 206, and used for the next image formation. The toner image thus obtained on the photoconductor 11 is transferred onto the transfer paper by the transfer roller 213 and then thermally fixed by a fixing device (not shown) to obtain a copied image.

Examples of the developer of the invention will be described. The present invention is not limited to this.

Table 1 shows one example of the material composition of the toner base particles of the present invention.

[0176]

[Table 1]

The measurement results of the fluidity of each toner and the charge amount of the developer in which the toner and the carrier are mixed are shown in (Table 2).

Flowability was defined as static bulk density. For the measurement, a powder tester PT-E type manufactured by Hosokawa Micron was used.

The amount of electrification was measured by the blow-off method and sample 0.2
g, 180 seconds with air pressure of 0.2 kgf / cm ²
It was blown and measured. The measurement conditions were that the carrier was mixed with a toner concentration of 10%, put in a 100 ml polyethylene bottle, and stirred at a rotation speed of 60 rpm for 10 minutes.

[0180]

[Table 2]

Table 3 shows the external additives used in the examples and the characteristics of the external additives. TA-1 is barium titanate fine particles produced by hydrothermal synthesis, TA-2 is barium zirconate fine particles produced by hydrothermal synthesis, and TA-3 is strontium titanate produced by oxalate pyrolysis. .

[0182]

[Table 3]

The barium titanate fine particles obtained by the hydrothermal synthesis method are prepared by mixing hydrous titanium oxide with barium hydroxide to obtain 20
It is obtained by reacting under a hydrothermal condition of 0 degree, followed by washing, filtering, drying and crushing. Molar ratio is Ba / Ti 0.99
8

The chargeability of the external additive is measured under the same conditions as the charge amount of the developer. The difference is that instead of the ferrite carrier, the coarsely pulverized toner base particles before pulverization have an opening diameter of 100 μm. What was sieved with a mesh of diameter was used. The mixed concentration is 10%.

The specific surface area is measured by an ordinary BET measuring method,
Shimadzu specific surface area measuring device FlowSorb2-2
300 was used.

As the static bulk density of the external additive, a powder tester PT-E type manufactured by Hosokawa Micron Co., Ltd. was used as in the toner.

The DBP oil absorption was determined by absorbing 20.00 g (A) of a sample dried at 150 ° C. + 1 ° C. for 1 hour with an absorber meter (manufactured by Brabender, spring tension 2.68 k).
(g / cm) and put the limit switch in the position of about 70% of the maximum torque in advance to rotate the mixed rotating machine. At the same time, DBP from automatic viewlet
(Specific gravity 1.045 to 1.050) is added at a rate of 4 ml / min. The torque rapidly increases near the end point and the limit switch is turned off. DBP added by then
From the amount (Bml), the DBP oil absorption (Dml / 100g) is expressed as a percentage ratio of A / B. Also, PH is 10g sample
100 ml of distilled water was added to the solution, and after boiling on a hot plate for 10 minutes and cooling to room temperature, the supernatant was separated and the pH of the mud was measured using a glass electrode PH meter.

The production of the toner of the present invention will be described.
The mixture shown in (Table 1) was used as a Henschel mixer FM20.
Mix with B (Mitsui Miike Co., Ltd.). The mixture is heated and kneaded with a twin-screw kneading extruder PCM30 (manufactured by Ikegai Tekko KK). The kneaded product is roughly crushed to a size of 2 mm or less with a coarse crusher Rotoplex (manufactured by Alpine). Then, fine pulverization is performed with a jet mill pulverizer IDS-2 type (made by Nippon Pneumatic Mfg. Co., Ltd.). Air flow classifier DS2
Cut fine powder with a mold (made by Nippon Pneumatic Mfg. Co., Ltd.). By the above treatment, toner base particles having an average particle diameter of 8 μm were obtained. After that, an external additive is externally added to obtain a toner.

Thereafter, the carrier and the toner were mixed with a tumbler mixer at a mixing ratio of 3% for 1 hour.

The material composition of the developer A1 of the present invention is shown in (Table 4).
Shown in

[0191]

[Table 4]

Barium titanate fine particles and hydrophobic silica treated with polydimethyl silicone oil were used as external additives.

As shown in (Table 2), it is understood that the developer A1 has high fluidity and high charging property. (The fluidity is a value only for the toner.) Also, as shown in (Table 3), it is understood that the barium titanate fine particles of the present invention have an antistatic property with respect to the toner base particles and hold high.

Using the electrophotographic apparatus shown in FIG. 1, a copying test was conducted using the developer A1 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, horizontal lines are not disturbed, toner is not scattered, there are no hollow characters, and a solid black image is uniform with a density of 1.4 16 / m.
An extremely high-resolution and high-quality image in which an image line of m was reproduced was obtained. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Also in the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density.

Example 2 The material composition of the developer A2 of the present invention is shown in (Table 5).

[0197]

[Table 5]

As the external additive, barium zirconate fine particles and hydrophobic silica treated with polydimethyl silicone oil were used.

Using the electrophotographic apparatus shown in FIG. 1, a copying test was conducted using the developer A2 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, horizontal lines are not disturbed, toner is not scattered, there are no hollow characters, and a solid black image is uniform with a density of 1.4 16 / m.
An extremely high-resolution and high-quality image in which an image line of m was reproduced was obtained. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Also in the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density. Example 3 The material composition of the developer A3 of the present invention is shown in (Table 6).

[0201]

[Table 6]

As the external additive, strontium titanate fine particles and hydrophobic silica treated with polydimethyl silicone oil were used.

Using the electrophotographic apparatus shown in FIG. 1, a copying test was conducted using the developer A3 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, horizontal lines are not disturbed, toner is not scattered, there are no hollow characters, and a solid black image is uniform with a density of 1.4 16 / m.
An extremely high-resolution and high-quality image in which an image line of m was reproduced was obtained. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Also in the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density.

(Embodiment 4) FIG. 2 is a sectional view of an electrophotographic apparatus according to an embodiment of the electrophotographic method of the present invention. This is a configuration in which a waste toner recycling step is further added to the configuration of the electrophotographic apparatus shown in FIG. 1 of the first embodiment. The toner remaining after the transfer is scraped off by the cleaning blade 218, and the waste toner 223 temporarily stored in the cleaning box 219.
To the toner hopper 2 of the developing device by a transport pipe 220.
It is a configuration for returning to 06.

Using the electrophotographic apparatus shown in FIG. 2, a copying test was conducted using the developer A1 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, horizontal lines are not disturbed, toner is not scattered, there are no hollow characters, and a solid black image is uniform with a density of 1.4 16 / m.
An extremely high-resolution and high-quality image in which an image line of m was reproduced was obtained. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, while recycling the waste toner, a long-term copying test of 10,000 sheets was conducted. 1000
There is no deterioration in the fluidity of the toner after 0 sheets, a high charge amount is maintained, and no filming occurs on the photoconductor. A high-density, low-ground fog copy image comparable to the initial image was obtained. The toner was recycled well.

(Example 5) A copying test was conducted using the developer A2 of the present invention using the electrophotographic apparatus shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the horizontal black line is not disturbed, the toner is not scattered, the characters are not missing, and the solid black image is uniform and the density is 1.4.
An image with extremely high resolution and high quality was obtained, which reproduced the image lines of 16 lines / mm. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, while recycling the waste toner, a long-term copying test of 10,000 sheets was conducted. 1000
There is no deterioration in the fluidity of the toner after 0 sheets, a high charge amount is maintained, and no filming occurs on the photoconductor. A high-density, low-ground fog copy image comparable to the initial image was obtained. The toner was recycled well.

Example 6 A copying test was conducted using the developer A3 of the present invention, using the electrophotographic apparatus shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the horizontal black line is not disturbed, the toner is not scattered, the characters are not missing, and the solid black image is uniform and the density is 1.4.
An image with extremely high resolution and high quality was obtained, which reproduced the image lines of 16 lines / mm. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, while recycling the waste toner, a long-term copying test of 10,000 sheets was conducted. 1000
There is no deterioration in the fluidity of the toner after 0 sheets, a high charge amount is maintained, and no filming occurs on the photoconductor. A high-density, low-ground fog copy image comparable to the initial image was obtained. The toner was recycled well.

(Embodiment 7) FIG. 3 shows a sectional view of an electrophotographic apparatus of an embodiment of the electrophotographic method of the present invention. The operation when forming a color image will be described.

Reference numeral 1 denotes an outer casing of the color electrophotographic printer, and the right end face side in the drawing is the front face. 1A is a printer front plate, and the front plate is tilted and opened around the hinge shaft 1B on the lower side with respect to the printer outer casing 1 as shown by a dotted line,
It can be raised and closed freely as shown by the solid line. The operation of attaching / detaching the intermediate transfer belt unit 2 to / from the printer and the inspection / maintenance of the inside of the printer at the time of paper jam are performed by tilting the front plate 1A open to largely open the inside of the printer. The attachment / detachment operation of the intermediate transfer belt unit 2 is designed so as to be perpendicular to the direction of the rotation axis generatrix of the photoconductor.

The structure of the intermediate transfer belt unit 2 is shown in FIG. The intermediate transfer belt unit 2 includes a unit housing 2a, a transfer belt 3, a first transfer roller 4 made of a conductive elastic body, a second transfer roller 5 made of an aluminum roller, and a tension roller 6 for adjusting the tension of the transfer belt.
The belt cleaner roller 7 for cleaning the toner image remaining on the transfer belt, the scraper 8 for scraping the collected toner on the cleaner roller 7, the waste toner reservoirs 9a and 9b for storing the collected toner, and the position of the transfer belt are detected. The position detector 10 is included. The intermediate transfer belt unit 2 is attachable to and detachable from a predetermined storage portion in the printer outer casing 1 by tilting down the printer front plate 1A as shown by a dotted line in FIG.

The intermediate transfer belt 3 is used by kneading a conductive filler in an insulating resin and forming a film with an extruder. In this embodiment, a polycarbonate resin (for example, Iupilon Z300 manufactured by Mitsubishi Gas Chemical Co., Inc.) 95 is used as the insulating resin.
Conductive carbon (eg Ketjen Black) 5
A part was added to form a film. The surface was coated with a fluororesin. The film had a thickness of about 350 μm and a resistance of about 10 ⁷ to 10 ⁸ Ω · cm.

This transfer belt is made of a film having a 100 μm-thick endless belt-shaped semiconductive urethane as a base material, and is subjected to low resistance treatment so as to have a resistance of 10 ⁷ Ω · cm in the periphery. Is wound around the molded first transfer roller 4, second transfer roller 5 and tension roller 6, and is movable in the direction of the arrow. Here, the peripheral length of the transfer belt is a length (62 mm) slightly longer than a half of the peripheral length of a photosensitive drum (diameter 30 mm), which will be described later, in the length (298 mm) in the longitudinal direction of A4 paper, which is the maximum paper size. Is set to 360 mm.

When the intermediate transfer belt unit 2 is mounted on the printer body, the first transfer roller 4 is attached to the photosensitive member 11 (shown in FIG. 3) by about 1.0 via the intermediate transfer belt 3.
The second transfer roller 5 is pressed with a force of kg, and the second transfer roller 5 is pressed with the third transfer roller 12 (shown in FIG. 3) having the same structure as the first transfer roller 4 through the intermediate transfer belt 3. . The third transfer roller is configured to be driven and rotatable by the intermediate transfer belt 3.

The cleaner roller 7 is a roller of a belt cleaner section for cleaning the intermediate transfer belt 3. This is a configuration in which an AC voltage that electrostatically attracts toner is applied to a metallic roller. The cleaner roller 7 may be a rubber blade or a conductive fur brush to which a voltage is applied.

Returning again to FIG. Black in the center of the printer,
Four sets of fan-shaped image forming units 17Bk, 17Y, 17M, and 17C for each color of cyan, magenta, and yellow constitute an image forming unit group 18, and are arranged in an annular shape as shown in the drawing. Each image forming unit is a printer top plate 1C.
Is detachable at a predetermined position of the image forming unit group 18 with the hinge shaft 1D opened. The image forming unit 17 is properly mounted in the printer, so that the mechanical drive system and the electric circuit system on both the image forming unit side and the printer side are connected via a mutual coupling member (not shown). Integrate mechanically and electrically.

Image forming unit 1 arranged in an annular shape
7Bk, 17C, 17M and 17Y are supports (not shown)
A cylindrical shaft 2 which is supported by a moving motor 19 which is a moving means as a whole and which is fixed and does not rotate.
It is configured to be rotatable around 0. Each image forming unit has an image forming position 2 facing the second transfer roller 4 which supports the intermediate transfer belt 3 in sequence by rotational movement.
Can be located at 1. The image forming position 21 is the signal light 2
It is also the exposure position by 2.

Since each image forming unit is composed of the same constituent members except the developer contained therein, the image forming unit 17Bk for black will be described and the other colors will be omitted for simplification of description. For each color,
The same portions are denoted by the same reference numerals, and when it is necessary to distinguish the configurations of the respective colors, the reference numerals are assigned with the letters indicating the respective colors. For the development, a development method used in a usual electrophotographic method was used.

Returning to FIG. 3 again, description will be made. Reference numeral 35 denotes a laser beam scanner section arranged in the lower side of the printer exterior casing 1, which is composed of a semiconductor laser, a scanner motor 35a, a polygon mirror 35b, a lens system 35c, and the like.
The pixel laser signal light 22 corresponding to the time-series electric pixel signal of the image information from the scanner unit 35 is supplied to the image forming unit 17
After passing through the optical path window 36 formed between Bk and 17Y,
The light enters the fixed mirror 38 in the shaft 20 through a window 37 opened in a part of the shaft 20 and is reflected to form an image forming position 2.
1 through the exposure window 25 of the image forming unit 17Bk into the image forming unit 17Bk almost horizontally, and passes through the passage between the developer reservoir 26 and the cleaner 34 which are vertically arranged in the image forming unit. Is incident on the exposed portion on the left side surface of the photoconductor drum 11, and scanning exposure is performed in the generatrix direction.

Here, since the optical path from the optical path window 36 to the mirror 38 uses the space between the image forming units 17Bk and 17Y on both sides, the image forming unit group 1
In 8 there is almost no wasted space. Also, mirror 3
Since the image forming unit group 8 is provided at the center of the image forming unit group 18, the image forming unit group 8 can be formed by a single fixed mirror, and the structure is simple and easy to align.

Reference numeral 12 denotes a third transfer roller disposed inside the printer front plate 1A and above the feeding roller 39. The nip portion where the intermediate transfer belt 3 and the third transfer roller 12 are pressed against each other has a printer. A sheet conveying path is formed so that the sheet is fed by the sheet feeding roller 39 provided below the front plate 1A.

Reference numeral 40 denotes a paper feed cassette provided on the lower side of the printer front plate 1A so as to project outward, and a plurality of papers S can be set at the same time. 41a and 41b are paper conveyance timing rollers, 42a and 42b are fixing roller pairs provided on the upper inside of the printer, 43 is a paper guide plate provided between the third transfer roller 12 and fixing roller pairs 42a and 42b, and 44a.
44b is a paper discharge roller pair arranged on the paper exit side of the fixing roller pairs 42a and 42b, 45 is a fixing oil reservoir for storing silicone oil 46 to be supplied to the fixing roller 42a, and 47 is silicone oil 46 applied to the fixing roller 42a. It is an oil supply roller. The above is the description of the main configuration of the electrophotographic apparatus of the present invention.

In the electrophotographic apparatus of the present invention, each image forming unit and the intermediate transfer belt unit are provided with a waste toner reservoir. When the toner of the present invention is used, since the transfer rate is high, almost no waste toner is generated, so that the volume can be made very small.

Initially, the image forming unit group 18 is in the position shown in FIG. 3, and the black image forming unit 17Bk is in the image forming position 21 as shown. At this time, the photoconductor 11 is in contact with the first transfer roller 4 via the intermediate transfer belt 3 so as to face it.

In the image forming step, the black signal light is input to the image forming unit 17Bk by the laser exposure device 35,
Image formation is performed using black toner. At this time, the image forming speed of the image forming unit 17Bk (equal to the peripheral speed of the photoreceptor 60
mm / s) and the moving speed of the intermediate transfer belt 3 are set to be the same, and the black toner image is transferred to the intermediate transfer belt 3 by the action of the first transfer roller 4 simultaneously with the image formation. At this time, a DC voltage of +1 kV was applied to the first transfer roller. Immediately after all the black toner images have been transferred, the image forming units 17Bk, 17C, 17M and 17Y
The image forming unit group 18 is entirely driven by a moving motor 19 and rotationally moves in the direction of the arrow in FIG.
The image forming unit 17C rotates once and stops at the position where it reaches the image forming position 21. During this time, the portions of the toner hopper 26 and the cleaner 34 other than the photosensitive member of the image forming unit are not covered by the photosensitive member 1.
The intermediate transfer belt 3 does not come into contact with the image forming unit because it is located inside the rotation arc of the first tip.

After the image forming unit 17C arrives at the image forming position 21, the laser exposure device 35 inputs the signal light to the image forming unit 17C by the cyan signal as before, and the cyan toner image is formed and transferred. Done. By this time, the intermediate transfer belt 3 has rotated once, so that the next cyan toner image is positionally aligned with the previously transferred black toner image.
The writing timing of the cyan signal light is controlled. During this time, the third transfer roller 12 and the cleaner roller 7 are slightly apart from the intermediate transfer belt 3 so that the toner image on the transfer belt is not disturbed.

The same operation as described above was performed for magenta and yellow, and toner images of four colors were positionally aligned and superposed on each other to form a color image. After the final transfer of the yellow toner image, the four color toner images were collectively transferred onto the paper fed from the paper feed cassette 40 at the same timing by the action of the third transfer roller 12. At this time, the second transfer roller 5 is grounded, and the third transfer roller 12 is
A DC voltage of +1.5 kV was applied to. The toner image transferred onto the sheet was fixed by the pair of fixing rollers 42a and 42b. The sheet is then discharged to the outside of the apparatus via the pair of discharge rollers 44a and 44b. The transfer residual toner remaining on the intermediate transfer belt 3 is cleaned by the action of the cleaner roller 7 to prepare for the next image formation.

Next, the operation in the monochrome mode will be described. In the single color mode, the image forming unit of a predetermined color first moves to the image forming position. Next, as in the previous case, image formation of a predetermined color and transfer to the intermediate transfer belt 3 are performed, and this time, after the transfer, the operation is continued as it is, and the next third transfer roller 12 is used to feed the paper cassette 40.
I transferred it to the paper sent from and fixed it as it was.

Using the electrophotographic apparatus shown in FIG. 3, a copying test was conducted using the developer A1 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, horizontal lines are not disturbed, toner is not scattered, there are no hollow characters, and a solid black image is uniform with a density of 1.4 16 / m.
An extremely high-resolution and high-quality image in which an image line of m was reproduced was obtained. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

In the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density. The transfer efficiency was 92%.

(Example 8) A copying test was conducted using the developer A2 of the present invention using the electrophotographic apparatus shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the horizontal black line is not disturbed, the toner is not scattered, the characters are not missing, and the solid black image is uniform and the density is 1.4.
An image with extremely high resolution and high quality was obtained, which reproduced the image lines of 16 lines / mm. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

In the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density. The transfer efficiency was 91%.

Example 9 Using the electrophotographic apparatus shown in FIG. 3, a copying test was conducted with the developer A3 of the present invention. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the horizontal black line is not disturbed, the toner is not scattered, the characters are not missing, and the solid black image is uniform and the density is 1.4.
An image with extremely high resolution and high quality was obtained, which reproduced the image lines of 16 lines / mm. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

In the long-term durability test of 10,000 sheets,
It shows stable characteristics with little change in fluidity and image density.

(Embodiment 10) A copying test was conducted using the developer A1 of the present invention, with the image forming step in the arrangement of the developing step shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, an extremely high-resolution and high-quality image is obtained, in which horizontal lines are not disturbed, toner is not scattered, hollow characters are not present, and a solid black image is uniform and 16 lines / mm with a density of 1.4 are reproduced. Was given. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, a long-term copying test of 10,000 sheets was conducted. There is no decrease in the fluidity of the toner after 10,000 sheets, a high charge amount is maintained, and filming does not occur on the photoconductor or the intermediate transfer belt. A high-density, low-ground fog copy image comparable to the initial image was obtained. The transfer efficiency was 93%.

(Embodiment 11) A copying test was conducted using the developer A2 of the present invention with the image forming step in the arrangement of the developing step shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, an extremely high-resolution and high-quality image is obtained, in which horizontal lines are not disturbed, toner is not scattered, hollow characters are not present, and a solid black image is uniform and 16 lines / mm with a density of 1.4 are reproduced. Was given. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, a long-term copying test of 10,000 sheets was conducted. There is no decrease in the fluidity of the toner after 10,000 sheets, a high charge amount is maintained, and filming does not occur on the photoconductor or the intermediate transfer belt. A high-density, low-ground fog copy image comparable to the initial image was obtained. The transfer efficiency was 90%.

(Embodiment 12) A copying test was conducted using the developer A3 of the present invention with the image forming step in the arrangement of the developing step shown in FIG. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, an extremely high-resolution and high-quality image is obtained, in which horizontal lines are not disturbed, toner is not scattered, hollow characters are not present, and a solid black image is uniform and 16 lines / mm with a density of 1.4 are reproduced. Was given. A high-density image having an image density of 1.4 or more was obtained. No background fog has occurred in the non-image area.

Then, a long-term copying test of 10,000 sheets was conducted. There is no decrease in the fluidity of the toner after 10,000 sheets, a high charge amount is maintained, and filming does not occur on the photoconductor or the intermediate transfer belt. A high-density, low-ground fog copy image comparable to the initial image was obtained. The transfer efficiency was 90%.

(Comparative Example 1) A developer B1 was produced as a trial with the same composition and formulation as in Example 1 except that the external additives were different.

Table 7 shows the material composition of the phenomenon agent B1.

[0246]

[Table 7]

As the external additive, strontium titanate fine particles prepared by calcination and mechanical grinding and hydrophobic silica surface-treated with dimethyldichlorosilane were used.

Using the electrophotographic apparatus shown in FIG. 1 of Example 1, a copying test was conducted with the developer B1. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image has a low image density and a large amount of background fog.

In the long-term copying test, toner filming occurred after about 2000 sheets.

(Comparative Example 2) A developer B2 was prepared as a trial with the same composition and formulation as in Example 1 except that the external additives were different.

Hydrophobic silica and alumina fine particles surface-treated with hexamethyldisilazane were used as external additives.

Using the electrophotographic apparatus shown in Example 1,
A copy test was conducted with the developer B2. The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image density was slightly low and the image was heavily fogged.

In the long-term copying test, toner filming occurred after 1000 sheets.

(Comparative Example 3) Using the electrophotographic apparatus shown in FIG. 2 of Example 4, a copying test was conducted with the developer B1.
The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image density was slightly low and the image was heavily fogged.

In the long-term copying test, toner filming occurred after about 2000 sheets.

(Comparative Example 4) Using the electrophotographic apparatus shown in FIG. 2 of Example 4, a copying test was conducted with the developer B2.
The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image density was slightly low and the image was heavily fogged.

In the long-term copying test, toner filming occurred after 1000 sheets.

Comparative Example 5 Using the electrophotographic apparatus of Example 7 shown in FIG. 3, a copying test was conducted with the developer B1.
The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image density was slightly low and the image was heavily fogged.

In the long-term copying test, toner filming occurred after about 2000 sheets.

(Comparative Example 6) Using the electrophotographic apparatus of Example 7 shown in FIG. 3, a copying test was conducted using the developer B2.
The image density was measured by a reflection densitometer (Macbeth) and evaluated. As a result, the image density was slightly low and the image was heavily fogged.

In the long-term copying test, toner filming occurred after 1000 sheets.

[0262]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, there are provided an image carrier which includes a fixed magnet and moves, and an electrode roller which is installed at a position having a predetermined gap from the surface of the image carrier and which has a magnet inside. Electro-photographic method that has a developing process consisting of an electrode roller, a transferring process using an intermediate transfer member, and a process of recycling waste toner, is synthesized by a hydrothermal method or an oxalic acid method defined by an average particle size and a specific surface area. By using a developer comprising a toner containing silica fine particles surface-treated with inorganic oil and a silicone oil and a carrier of magnetic particles coated with a fluororesin containing a specific conductive powder, high fluidity, Highly chargeable toner is obtained, and high density, low background fog and high image quality can be realized in a high performance, small size, and low cost developing method.

Further, it is possible to provide a developer capable of preventing a hollow portion at the time of transfer, suppressing the occurrence of toner filming on the photoconductor even when the waste toner is recycled, and obtaining a stable image.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an electrophotographic apparatus in which an electrophotographic method according to an embodiment of the present invention is used.

FIG. 2 is a sectional view showing a main part of an electrophotographic apparatus in which an electrophotographic method according to an embodiment of the present invention is used.

FIG. 3 is a sectional view showing a main part of an electrophotographic apparatus in which an electrophotographic method according to an embodiment of the present invention is used.

FIG. 4 is a configuration diagram of an intermediate transfer belt unit according to an embodiment of the present invention.

FIG. 5 is a block diagram of a conventional color electrophotographic apparatus.

[Explanation of symbols]

 2 Intermediate Transfer Belt Unit 3 Intermediate Transfer Belt 4 First Transfer Roller 5 Second Transfer Roller 6 Tension Roller 11 Photoconductor 12 Third Transfer Roller 15 Spring 16 Roller 17Bk / 17C / 17M / 17Y Image Forming Unit 18 Image Forming Unit Group 21 Image forming position 22 Laser signal light 35 Laser exposure device 38 Mirror 202 Fixed magnet 203 contained in photoconductor 203 Corona charger 204 Grid electrode 206 Toner hopper 207 Developer 208 Electrode roller 209 Magnet installed inside electrode roller 211 Scraper 213 Transfer roller 214 Entry guide 215 Conveyance guide 216 Transfer paper 218 Cleaning blade 219 Waste toner box 220 Waste toner transport pipe 223 Waste toner

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location G03G 9/10 361 (72) Inventor Masatoshi Maeda 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. Within

Claims (26)

[Claims] 1. A fluorocarbon resin containing a conductive fine powder is used as a surface coating.
Made of magnetic particles having an average particle size of 20 to 100 μm
Carrier and at least binder resin, charge control agent, coloring
And a toner composed of an external additive and a toner.
Thus, the conductive powder has at least a DBP oil absorption of 160
(Ml / 100g) or more, BET specific surface due to nitrogen adsorption
Product is 500-1300m²/ G, carbon of PH7 or more
It consists of black, and the external additive is at least hydrothermal method or oxalate heat.
The average particle size synthesized by the decomposition method is 0.05 to 4 μm,
BET specific surface area due to elementary adsorption is 0.1 to 40 m ²/ G
Surface treated with certain inorganic particles and silicone oil
BET specific surface area due to absorbed nitrogen is 50 to 350 m²
/ G of hydrophobic silica fine powder
Developer. 2. The developer according to claim 1, wherein the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles. 3. The inorganic fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. The described developer. 4. The developer according to claim 1, wherein the hydrophobic silica fine particles are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. 5. An image bearing member including a fixed magnet and moving, and developing.
A predetermined gap was formed between the agent hopper and the surface of the image bearing member.
Position and a developer recovery electrode roller with a magnet inside
In the electrophotographic device, an electrostatic latent image is formed on the image carrier.
After being formed, the image bearing located in the developer hopper is formed.
The developer is magnetically attracted to the surface of the holder to carry the image.
The developer is carried on the surface of the body, and the image carrier is moved.
The developer recovery electrode roller, and
The carrier on the carrier and the toner in the non-image area are collected by the developer.
Development that collects with electrode roller and leaves toner on the image
And a toner that visualizes the electrostatic latent image on the image carrier.
A transfer step of transferring the toner onto a transfer sheet by electrostatic force, and the toner partially remaining on the image carrier during the transfer step.
Cleaning step of removing the image from the image carrier.
At least the developer used for the electrophotographic method
The surface of the developer is a fluororesin containing conductive fine powder.
It consists of coated magnetic particles with an average particle size of 20 to 100 μm.
Carrier, at least binder resin, charge control agent, coloring
And a toner comprising an external additive, wherein the conductive powder has at least a DBP oil absorption of 160
(Ml / 100g) or more, BET specific surface due to nitrogen adsorption
Product is 500-1300m²/ G, carbon of PH7 or more
It consists of black, and the external additive is at least hydrothermal method or oxalate heat.
The average particle size synthesized by the decomposition method is 0.05 to 4 μm,
BET specific surface area due to elementary adsorption is 0.1 to 40 m ²/ G
Surface treated with certain inorganic particles and silicone oil
BET specific surface area due to absorbed nitrogen is 50 to 350 m²
/ G of hydrophobic silica fine powder
Developer. 6. The developer according to claim 5, which is used in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal development method is visualized with toner. 7. The developer according to claim 5, wherein the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles. 8. The inorganic fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. The described developer. 9. The developer according to claim 5, wherein the hydrophobic silica fine particles are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. 10. An image carrier that includes a fixed magnet and moves, and
Has a predetermined gap between the image hopper and the surface of the image carrier.
And a developer collecting electrode roller that has a magnet inside
An electrophotographic apparatus having the electrostatic latent image on the image carrier.
The image located in the developer hopper after forming
The developer is magnetically attracted to the surface of the carrier to carry the image.
The developer is carried on the surface of the carrier, and the image carrier is transferred.
The developer collecting electrode roller to move the image.
The carrier on the carrier and the toner in the non-image area are
The current configuration is such that the toner is collected by the collecting electrode roller and the toner remains on the image area.
An image process, and the toner that visualizes the electrostatic latent image on the image carrier
A transfer step of transferring the toner onto a transfer sheet by electrostatic force, and the toner partially remaining on the image carrier during the transfer step.
A cleaning step of removing the toner from the image carrier, and the toner removed in the cleaning step before again.
Toner recycling process that returns to the developing process and reuses,
Is a developer used in an electrophotographic method having at least
The surface of the developer is a fluororesin containing conductive fine powder.
It consists of coated magnetic particles with an average particle size of 20 to 100 μm.
Carrier, at least binder resin, charge control agent, coloring
And a toner comprising an external additive, wherein the conductive powder has at least a DBP oil absorption of 160
(Ml / 100g) or more, BET specific surface due to nitrogen adsorption
Product is 500-1300m²/ G, carbon of PH7 or more
It consists of black, and the external additive is at least hydrothermal method or oxalate heat.
The average particle size synthesized by the decomposition method is 0.05 to 4 μm,
BET specific surface area due to elementary adsorption is 0.1 to 40 m ²/ G
Surface treated with certain inorganic particles and silicone oil
BET specific surface area due to absorbed nitrogen is 50 to 350 m²
/ G of hydrophobic silica fine powder
Developer. 11. The developer according to claim 10, which is used in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal development method is visualized with toner. 12. The developer according to claim 10, wherein the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles. 13. The inorganic fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. The described developer. 14. The developer according to claim 10, wherein the hydrophobic silica fine particles are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. 15. An electrostatic latent image formed on an image bearing member is coated with toner.
Development step to visualize by means of carbon black in which the toner is brought into contact with the image carrier
Endless type whose basic component is a polycarbonate containing
Primary transfer to the intermediate transfer member, and the primary transfer step
Process of operating multiple times to form a transferred toner overlap image
And the transfer toner overlapping image formed on the intermediate transfer member.
Secondarily transfer all the sheets to the image receiving paper that is conveyed from the paper feed side
Developing for use in an electrophotographic method having at least
A developing agent, wherein the developer is a fluororesin containing conductive fine powder
It consists of coated magnetic particles with an average particle size of 20 to 100 μm.
Carrier, at least binder resin, charge control agent, coloring
And a toner comprising an external additive, wherein the conductive powder has at least a DBP oil absorption of 160
(Ml / 100g) or more, BET specific surface due to nitrogen adsorption
Product is 500-1300m²/ G, carbon of PH7 or more
It consists of black, and the external additive is at least hydrothermal method or oxalate heat.
The average particle size synthesized by the decomposition method is 0.05 to 4 μm,
BET specific surface area due to elementary adsorption is 0.1 to 40 m ²/ G
Surface treated with certain inorganic particles and silicone oil
BET specific surface area due to absorbed nitrogen is 50 to 350 m²
/ G of hydrophobic silica fine powder
Developer. 16. The developer according to claim 15, which is used in an electrophotographic method, which is an intermediate transfer member surface-treated with a fluororesin. 17. The developer according to claim 15, which is used in an electrophotographic method in which an electrostatic latent image formed on an image carrier by a reversal development method is visualized with toner. 18. The developer according to claim 15, wherein the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles. 19. The inorganic fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. The described developer. 20. The developer according to claim 15, wherein the hydrophobic silica fine particles are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. 21. An image carrier that includes a fixed magnet and moves, and
Has a predetermined gap between the image hopper and the surface of the image carrier.
And a developer collecting electrode roller that has a magnet inside
An electrophotographic apparatus having the electrostatic latent image on the image carrier.
The image located in the developer hopper after forming
The developer is magnetically attracted to the surface of the carrier to carry the image.
The developer is carried on the surface of the carrier, and the image carrier is transferred.
The developer collecting electrode roller to move the image.
The carrier on the carrier and the toner in the non-image area are
The current configuration is such that the toner is collected by the collecting electrode roller and the toner remains on the image area.
Image step, and the toner image obtained by visualizing the electrostatic latent image on the image carrier
Containing carbon black in contact with the image carrier
Endless intermediate transfer member containing polycarbonate as a basic component
To the primary transfer, and the development process and the primary transfer process are repeated.
The transferred toner overlap image is formed by operating several times, and the intermediate transfer is performed.
The duplicate toner image formed on the object is conveyed from the paper feed side.
A transfer process that performs a secondary transfer all at once to the image receiving paper that is sent,
A developer used in the electrophotographic method, which is composed of a fluororesin containing conductive fine powder
A carrier composed of magnetic particles having a particle size of 20 to 100 μm,
At least from binder resin, charge control agent, colorant, external additive
And a toner having a DBP oil absorption of 160 or more.
(Ml / 100g) or more, BET specific surface due to nitrogen adsorption
Product is 500-1300m²/ G, carbon of PH7 or more
It consists of black, and the external additive is at least hydrothermal method or oxalate heat.
The average particle size synthesized by the decomposition method is 0.05 to 4 μm,
BET specific surface area due to elementary adsorption is 0.1 to 40 m ²/ G
Surface treated with certain inorganic particles and silicone oil
BET specific surface area due to absorbed nitrogen is 50 to 350 m²
/ G of hydrophobic silica fine powder
Developer. 22. The developer according to claim 21, which is used in an electrophotographic method, which is an intermediate transfer member surface-treated with a fluororesin. 23. The developer according to claim 21, which is used in an electrophotographic method in which an electrostatic latent image formed on an image bearing member by a reversal developing method is visualized with toner. 24. The developer according to claim 21, wherein the inorganic fine particles synthesized by the hydrothermal method or the oxalate thermal decomposition method are titanate fine particles or zirconate fine particles. 25. The inorganic fine particles synthesized by a hydrothermal method or an oxalate thermal decomposition method are contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the toner. The described developer. 26. The developer according to claim 21, wherein the hydrophobic silica fine particles are contained in an amount of 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the toner.