JPH08248670A - One-component developer - Google Patents

Abstract

PURPOSE: To provide a one-component developer which is provided with an excellent storage property and forms an excellent image having no inside lack when it is used for a pressure transfer system image forming device, especially, for a full-color image developing device. CONSTITUTION: A one-component developer, which is used for a one-component developing device provided with a developer carrying body and a developer restricting member arranged so as to be brought into pressure contact with or close to the developer carrying body, consists of a toner grain, which contains a binder resin and a coloring agent, and an external additive, which is externally added and mixed with the toner grains, and the external additive is made of anatase type titanium dioxide, in which the surface is treated by a hydrophobic agent and a fluorine group silane coupling agent while an average primary particulate diameter of 10-90nm is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component developer used in an image forming apparatus such as an electrostatic copying machine or a laser beam printer, and more particularly, to a developer carrier and a developer carrier which is in contact with the developer carrier. One-component developer used in a one-component developing device having a developer regulating member arranged therein, one-component developing used in an image forming device for performing transfer from an electrostatic latent image carrier to recording paper by pressure transfer And a non-magnetic one-component developer used in a full-color image forming apparatus for performing primary transfer and secondary transfer by pressure transfer.

[0002]

2. Description of the Related Art Electrophotographic systems are used for copying machines, printers,
It is widely used in facsimiles and the like, and in recent years, a downsized image forming method has been adopted due to the demand for personal use. In such an image forming apparatus, a two-component developing system and a one-component developing system are adopted as a developing device.

In the two-component developing system, a toner and a carrier are used as a developer, and the consumed toner is replenished newly, but the carrier is not replenished, so that the carrier deteriorates as it is used (contamination of the carrier by the toner component). (Spent) lowers the charging performance for the toner). Further, in response to the demand for downsizing of the image forming apparatus, the two-component developing apparatus requires a mechanism for mixing and agitating the toner and the carrier, and thus there is a limitation in downsizing of the developing apparatus.

In contrast to the two-component developing system, the one-component developing system does not use a carrier, so that the problem of carrier deterioration does not essentially occur, and a mixing and stirring mechanism for toner and carrier is not required, so that the developing device is compact. The developing method is suitable for a small-sized image forming apparatus because it is easy to realize.

The one-component developing system includes a magnetic one-component developing system and a non-magnetic one-component developing system. However, in the magnetic one-component developing system, it is necessary to add magnetic powder, which is usually black, to the toner. A non-magnetic one-component developing system is suitable for the apparatus. From this point of view, the non-magnetic one-component developing method is preferable for full-color formation,
This method has a problem that it is difficult to supply toner having a uniform and predetermined charge amount to the developing area.

For example, in the above-described two-component developing method and magnetic one-component developing method, since the developer is conveyed by utilizing the magnetic force, it is relatively easy to stably supply the developer to the developing area. In the two-component developing method, the toner is charged by mixing and stirring the toner and the carrier, so that it is relatively easy to supply the sufficiently charged toner to the developing area.

In the non-magnetic one-component developing system, the developer regulating member is arranged so as to abut against the developer carrying member, and the non-magnetic one-component developer is distributed between the developer carrying member and the developer regulating member. The toner is charged by passing through the gap, and the charged toner is carried on the developer carrier mainly by the electrostatic force of the toner and conveyed to the development area, where the electrostatic latent image formed on the electrostatic latent image carrier is carried. The image is being developed. That is, since the toner is charged mainly by frictional charging when the toner passes through the gap between the developer carrier and the developer regulating member, it is difficult to uniformly charge the toner to a predetermined charge amount. Become. If the toner is not sufficiently charged,
Not only the toner charge amount becomes low, but also the oppositely charged toner occurs and the image is fogged. On the other hand, if the chargeability is too high, the amount of toner that adheres to the electrostatic latent image decreases, which causes a decrease in image density, and the electrostatic adhesion force to the electrostatic latent image carrier increases, which decreases transfer efficiency. Will occur.
This problem is remarkable when the toner has a small particle size in order to meet the demand for high image quality.

In the image forming apparatus described above,
The transfer of the toner image from the photoconductor to the recording paper is usually performed using a transfer device using corona discharge. As a transfer device that replaces the transfer device using corona discharge, for example, in JP-A-59-46664, a transfer device in which a bias is applied to a photoconductor is brought into pressure contact, and a recording paper is passed between them to expose the photoconductor. A device for transferring a toner image on the body to a transfer body has been proposed.

Since such a device presses the recording paper at the transfer portion as compared with a transfer device using corona discharge, there is less risk of synchronization failure or transfer deviation due to the recording paper conveying means, and size reduction of the image forming apparatus. There is an advantage that it is easy to meet the request for shortening the recording paper conveyance path and miniaturization of the photoconductor.

However, because a pressing force is applied to the toner image on the photosensitive member, a portion where the adhesion between the toner image and the photosensitive member is strong is generated and the transfer to the recording paper is hindered. There is a problem (lossiness) that images are missing.
This problem is likely to occur particularly in the case of an image having an edge effect like the two-component developing system.

In recent years, there has been an increasing demand for a full-color image forming apparatus that reproduces a multicolor image by superposing color toners of a plurality of colors even in the above-mentioned small-sized image forming apparatus.

2. Description of the Related Art Conventionally, a two-component developing system is usually employed in an electrophotographic full-color image forming apparatus. A cyan developer composed of cyan toner and carrier, a magenta developer composed of magenta toner and carrier, and a yellow toner. And a carrier, a yellow developer, and a black toner and a carrier, a black developer and four two-component developing devices, respectively, for transferring and superimposing the toner images formed on the photoconductor. And a transfer body. The transfer from the photoconductor to the intermediate transfer member (primary transfer) and the transfer from the intermediate transfer member to the recording paper (secondary transfer) are usually performed using a transfer device using corona discharge. As described above, in such an image forming apparatus, the two-component developing method and the corona transfer device are disadvantageous in reducing the size of the apparatus. Further, when the above-mentioned contact transfer device is adopted for a full-color image forming apparatus, when the full-color image is formed, the primary transfer by each toner is performed four times and the secondary transfer is performed once. It is necessary to solve the problem of hollow spots more than when forming a normal monochrome image.

Further, in view of the ease of handling by a user in personal use, in a small and inexpensive image forming apparatus, the developing device is made into a cartridge and the cartridge is replaced when the toner is used up, the photosensitive member, the developing device, and A configuration in which the cleaning device is integrally formed into a cartridge is used. Since such a cartridge is often stored in a high temperature environment where air conditioning is not performed as compared with the case of office use, higher heat-resistant storage property of the toner is required.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a one-component developer that solves the above problems. That is, the present invention is a one-component developing method including a developer carrying member and a developer regulating member disposed in contact with the developer carrying member, and a one-component developing method in which stability of the toner charge amount against negative chargeability and environmental changes is improved. The purpose is to provide a developer.

Another object of the present invention is to provide a one-component developer having improved heat resistant storage stability.

A further object of the present invention is to provide a one-component developer which solves the problem of voids in an image forming apparatus employing pressure transfer.

Further, the present invention solves the problem of voids and is excellent in environmental stability, and is suitable for a full-color image forming apparatus which performs primary transfer and secondary transfer by pressure transfer, and is a non-magnetic single-component development for full color. The purpose is to provide an agent.

[0018]

The present invention is used in a one-component developing device provided with a developer carrying member and a developer regulating member installed so as to be in pressure contact with or close to the developer carrying member. A one-component developer comprising toner particles containing a binder resin and a colorant, and an external additive externally mixed with the toner particles. The external additive has an average primary particle size. The present invention relates to a one-component developer having a diameter of 10 to 90 nm and comprising anatase type titania surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent.

According to the present invention, the electrostatic latent image formed on the electrostatic latent image carrier is developed with toner, and the formed toner image is pressed and transferred by the transfer roller via the recording paper. A one-component developer used in an image forming apparatus for forming an image, the developer including toner particles containing a binder resin and a colorant, and an external additive formed by external mixing with the toner particles. And an anatase-type titania surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent, the external additive having an average primary particle diameter of 10 to 90 nm.

Further, according to the present invention, a toner image is sequentially formed on the electrostatic latent image bearing member for each predetermined color, and the toner image is sequentially transferred by pressure transfer onto the intermediate transfer member by the transfer roller via the intermediate transfer member. A full-color non-magnetic one-component developer used in an image forming apparatus for forming a full-color image by pressing and transferring a toner image superposed on an intermediate transfer member with a transfer roller through a recording paper, The developer is composed of toner particles containing a binder resin and a colorant, and an external additive externally mixed with the toner particles. The external additive has an average primary particle size of 10 to 90 nm. The present invention relates to a non-magnetic one-component developer comprising anatase-type titania surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent.

The one-component developer of the present invention comprises toner particles containing at least a binder resin and a colorant, and an external additive externally mixed with the toner.

As the binder resin used in the present invention, a styrene resin, an acrylic resin, a styrene-acrylic resin, a polyamide resin, a polyester resin, a polyurethane resin, an epoxy resin and other known resins may be used alone or. They can be mixed and used, and a preferable one may be appropriately selected and used according to the application. For example, it is preferable to use a polyester resin for a negatively charged toner and a polyester resin for a full color toner.

As the colorant, various known colorants such as cyan color, magenta color, yellow color, and black color can be used, and the amount of the colorant used can be the same as the conventional value. Usually, the colorant is added in an amount of about 1 to 15 parts by weight based on 100 parts by weight of the binder resin.

In addition to the above colorants, desired additives such as charge control agents and offset preventing agents may be added to the toner of the present invention.

As the charge control agent, zinc salicylate complex or the like and other known charge control agents can be used.
The type may be selected according to the purpose of use. For full-color copying, it is preferable to use a colorless, white or pale yellow charge control agent. The amount of the charge control agent used may be appropriately set depending on the purpose of use, but usually,
It is used in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight, based on 100 parts by weight of the binder resin.

Also, the offset preventing agent is not particularly limited, and examples thereof include polyethylene wax, oxidized polyethylene wax, polypropylene wax,
Oxidized polypropylene wax, carnauba wax, sazol wax, rice wax, candelilla wax, jojoba oil wax, beeswax wax and the like can be used. The offset preventing agent may be appropriately set in an amount suitable for the purpose of use, but is usually used in an amount of 0.5 to 10 parts by weight, preferably 1 to 8 parts by weight, based on 100 parts by weight of the binder resin.

The toner particles according to the present invention can be produced by using the above-mentioned binder resin, colorant and other desired additives, and other known methods such as a kneading / pulverizing method and a suspension polymerization method. Among those manufacturing methods,
From the viewpoint of manufacturing cost and manufacturing stability, it is preferable to manufacture by a kneading / pulverizing method.

The kneading / pulverizing method includes the steps of mixing the toner components such as the resin and the colorant with a mixer such as a Henschel mixer, the step of melting and kneading the mixture, and the step of coarsely pulverizing the kneaded material after cooling. Toner particles are manufactured by a step of finely pulverizing the coarsely pulverized particles and a step of classifying the obtained finely pulverized particles.

The resulting toner particles are prepared as a one-component developer by adding and mixing external additives using a mixer such as a Henschel mixer. The toner of the present invention is preferably adjusted to have a volume average particle diameter of 5 to 10 μm from the viewpoint of high definition reproducibility of images.

In the one-component developer of the present invention, an average primary particle diameter of 10 to 10 is used as an external additive used by being mixed with toner particles.
Anatase type titania having a 90 nm surface treated with a hydrophobizing agent and a fluorinated silane coupling agent is used. By using such titania as an external additive, the negative charge of the one-component developer is improved and the environmental stability is improved.
(In particular, the stability of the toner charge amount with respect to changes in humidity) can be improved, and the problem of hollow defects at the time of pressure transfer can be solved. Further, by allowing a specific titania to be present on the surface of the toner as an external additive in this way, the thermally stable titania becomes a steric hindrance and prevents the aggregation of the toner due to the fluctuation of the ambient temperature (temperature rise). The heat-resistant storage property can be improved.

In the present invention, the average primary particle size is 10 to 90.
nm, preferably 40 to 90 nm, more preferably 40 to 7
Use 0 nm of anatase titania. Usually, anatase-type titania is needle-shaped or rod-shaped particles having an average primary particle size of about 200 nm, but those used in the present invention are those in which titania particles are needle-shaped particles or crystals are not grown. The shape is a substantially flaky shape to a substantially thin cylindrical shape. It is considered that due to such a shape and particle size, the adhesiveness to the toner and the mixing and dispersibility are excellent.

The anatase-type titania is obtained by suppressing the crystal growth by lowering the crystallization temperature in a known wet method. As such anatase type titania, commercially available products such as STT3
0 (average primary particle size 50 nm, manufactured by Titanium Industry Co., Ltd.) STT30A
(Average primary particle size of 15 to 20 nm, manufactured by Titanium Industry Co., Ltd.) and the like can be used.

The anatase type titania is 10 to 90.
Although those having a thickness of nm can be used, those having a thickness of 40 to 90 nm are preferably used from the viewpoints of improving the heat-resistant storage property, preventing hollow defects during transfer, and improving the durability of the developer.
The reason for the effect of preventing hollow defects is not clear, but it is presumed that it is because they function as a titania spacer during transfer. Further, regarding the effect of improving the durability of the developer, although the reason has not been clarified, the toner caused by the stress at the time of charging by the developer regulating member, the stress at the time of development and transfer, etc. It is presumed that this is because embedding of the titania particles into the particles is unlikely to occur. On the other hand, if it is larger than 90 nm, the adhesion to the toner is lowered, and as a result, the heat-resistant storage property is lowered and the charge amount of the toner is lowered, which is not preferable.

In the present invention, anatase titania is surface-treated with a hydrophobizing agent. This is to suppress the environmental stability of the toner, particularly, the change in the toner charge amount due to the influence of humidity. It is desirable that the hydrophobicity is 30 to 80%, preferably 40 to 80%. Hydrophobicity is 30%
If it is lower, the environment resistance is deteriorated, and if it exceeds 80%, it is difficult to obtain a stable product in manufacturing.

As the hydrophobizing agent, a silane coupling agent,
A titanate coupling agent, silicone oil, silicone varnish, etc. can be used. Examples of the silane coupling agent include trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, and dimethyl. Dimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, Vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane and the like can be used.

As the silicone oil, for example, dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenylpolysiloxane, etc. can be used. The hydrophobizing agent is 1 to 100 parts by weight of the above titania.
It is preferable to use 25 parts by weight, preferably 2 to 20 parts by weight. If it is less than 1 part by weight, there is no effect of hydrophobizing and 2
If it exceeds 5 parts by weight, the treated titania tends to aggregate. In the present invention, the anatase-type titania is further surface-treated with a fluorine-based silane coupling agent. This is to improve the negative chargeability of the toner and prevent image fog. Usually, the chargeability of the toner is controlled by including a charge control agent in the toner particles. In the one-component developing method according to the present invention, since the toner is charged by frictional charging when the toner passes through the gap of the pressure contact portion between the developer carrier and the developer regulating member,
The chargeability of the surface of the toner particles is important for the chargeability of the toner. Therefore, when controlling the chargeability, it is more effective to adjust the chargeability of the external additive of the toner than to adjust the content of the charge control agent.

As the fluorine-based silane coupling, for example, the following compounds may be used alone or as a mixture, but are not limited thereto. _{· CF 3 (CH 2) 2} SiCl 3 · CF 3 (CF 2) 5 SiCl 3 · CF 3 (CF 2) 5 (CH 2) 2 SiCl 3 · CF 3 (CF 2) 7 (CH 2) 2 SiCl 3 _{· CF 3 (CF 2) 7} CH 2 CH 2 Si (OCH 3) 3 · CF 3 (CF 2) 7 (CH 2) 2 Si (CH 3) Cl 3 · CF 3 (CH 2) 2 Si (OCH 3 _{) 3 · CF 3 (CH 2} ) 2 Si (CH 3) (OCH 3) 2 · CF 3 (CF 2) 3 (CH 2) 2 Si (OCH 3) 3 · CF 3 (CF 2) 5 (CH 2 ) ₂ Si (OCH ₃ ) ₃ · CF ₃ (CF ₂ ) ₆ CONH (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ · CF ₃ (CF ₂ ) ₆ COO (CH ₂ ) ₂ Si (OCH ₃ ) _{3 · CF3 (CF 2) 7 (} CH 2) 2 Si (OCH 3) 3 · CF 3 (CF 2) 7 (CH 2) 2 Si (CH 3) (OCH 3) 2 · CF 3 (CF 2) 7 NH _{(CH 2) 3 Si (OC} 2 H 5) 3 · CF 3 (CF 2) 8 (CH 2) 2 Si (OCH 3) 3

The fluorinated silane coupling agent is 1 to 20 parts by weight, preferably 2 to 100 parts by weight of titania.
It is preferable to use 15 parts by weight. If it is less than 1 part by weight, the effect of imparting negative charge is not obtained, and if it exceeds 20 parts by weight, titania after treatment tends to aggregate.

To surface-treat titania using the above-mentioned surface treatment agent (fluorine coupling agent, hydrophobizing agent),
For example, a surface treatment agent is diluted with a solvent, and the above diluent is added to titania and mixed, and the mixture is heated and dried, and then crushed by a dry method, in which titania is dispersed in an aqueous system to form a slurry. It can be carried out by a wet method in which a surface treatment agent is added and mixed, heated and dried, and then crushed. Particularly, from the viewpoint of the uniformity of the surface treatment of the hydrophobizing agent for titania, the anti-aggregation property of titania particles, etc., the hydrophobizing treatment of titania was performed in an aqueous system, and this titania was surface-treated with a fluorine-based coupling agent by a dry method. Those are preferable.

It is desirable that titania as an external additive in the present invention is mixed and added to the toner particles in an amount of 0.1 to 3.0% by weight, preferably 0.2 to 2.0% by weight. If the amount is less than 0.1% by weight, the effect of improving the environmental stability and the effect of preventing hollow defects become insufficient, and if the amount is more than 3.0% by weight, it causes the spot-like adhesion of the toner component to the photoreceptor. Become.

In the toner of the present invention, it is preferable to add and mix a fluidizing agent together with the above titania.

As such a fluidizing agent, for example, silica, alumina, titania, tin oxide, zirconium oxide and the like can be used alone or in admixture of two or more. The fluidizing agent is preferably subjected to a hydrophobizing treatment from the viewpoint of environmental stability, and as the hydrophobizing agent, various coupling agents such as silane-based, titanate-based, aluminum-based, zircoaluminate-based and silicone oil, etc. Is used.

In the present invention, it is preferable to use hydrophobic silica as the fluidizing agent from the viewpoint of improving fluidity.

The addition amount of the fluidizing agent is 0.1 with respect to the toner.
It is preferable to add 1 to 3.0% by weight, preferably 0.2 to 2.0% by weight. When a fluidizing agent is used with titania, each additive is in the above range and the total amount is 0.2-4.0% by weight, preferably 0.3-3.0.
It is preferably in the weight%. If the total amount is too large, the toner components adhere to the photosensitive member in spots, and if the total amount is too small, the effects of improving the fluidity and preventing hollow defects are insufficient.

An example of a full-color image forming apparatus using a non-magnetic one-component toner as a one-component developer in the present invention will be described below with reference to FIG. It should be noted that this full-color image forming apparatus performs both the primary transfer from the photosensitive member to the intermediate transfer member and the secondary transfer from the intermediate transfer member to the recording paper by the transfer roller in order to form a full-color image. The one-component developer of the present invention can also be applied to a monochrome image forming apparatus in which transfer from a photoconductor to recording paper is performed by pressure transfer by a transfer roller. In this case, a magnetic powder is used to form a color image. Since it is not necessary to consider the influence, it can be used not only as a non-magnetic one-component developer but also as a magnetic one-component developer containing magnetic powder.

In FIG. 1, the full-color laser beam printer is roughly driven to rotate in the direction of arrow a, the photosensitive drum 10, the laser scanning optical system 20, the full-color developing device 30, and to rotate in the direction of arrow b. It is composed of an endless intermediate transfer belt 40 and a sheet feeding section 60. Around the photosensitive drum 10, a charging brush 11,
The cleaner 12 is installed. The charging brush 11 uniformly charges the surface of the photoconductor drum 10 to a predetermined potential. The cleaner 12 uses a blade to scrape off the toner remaining on the photosensitive drum 10.

The laser scanning optical system 20 is a well-known one having a laser diode, a polygon mirror, and an fθ optical element built-in, and its control section has C (cyan), M (magenta), and Y.
Print data for each of (yellow) and Bk (black) is transferred from the host computer. The laser scanning optical system 20 sequentially outputs the print data for each color as a laser beam, and scans and exposes the photosensitive drum 10. As a result, electrostatic latent images of respective colors are sequentially formed on the photoconductor drum 10.

The full-color developing device 30 has C, M, Y, B
The four color developing devices 31C, 31M, 31Y, and 31Bk containing a developer containing k non-magnetic one-component toner are integrated, and can rotate in a clockwise direction with the support shaft 33 as a fulcrum. Each developing device has a developing sleeve 32 and a blade 3.
4a and 34b. This developing sleeve 32,
FIG. 2 shows a schematic enlarged view of the portions of the blades 34a and 34b for easy understanding. Developing sleeve 32
The toner conveyed by the rotation of is charged by passing through the pressure contact portion of the blades 34a and 34b to the developing sleeve 32. Each developing device is rotated and switched so that the developing sleeve 32 of the corresponding developing device is positioned at the developing portion D each time an electrostatic latent image of each color is formed on the photoconductor drum 10 to perform contact development. In this embodiment, the entire printer is made compact by using the rotary type full-color developing device 30.

The intermediate transfer belt 40 is rotationally driven in the direction of arrow b in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by the rotatable primary transfer roller 41 and comes into contact with the photosensitive drum 10, and this contact portion is the primary transfer portion T ₁ . Further, the intermediate transfer belt 40 is in contact with the rotatable secondary transfer roller 43 at the portion supported by the support roller 42. This contact portion is the secondary transfer portion T ₂ .

Further, a cleaner 50 is installed in the space between the developing device 30 and the intermediate transfer belt 40. The cleaner 50 has a blade for scraping off the residual toner on the intermediate transfer belt 40. The blade and the secondary transfer roller 43 can be brought into contact with and separated from the intermediate transfer belt 40.

The paper feeding section 60 is a paper feeding tray 6 which can be opened on the front side of the printer body 1 (the side where the operator is normally located).
1, a paper feed roller 62, and a timing roller 63. The recording sheets S are stacked on the paper feed tray 61, and are fed one by one to the right in FIG. 1 by the rotation of the paper feed roller 62, and are synchronized with the image formed on the intermediate transfer belt 40 by the timing roller 63. Secondary transfer section T
Sent to ₂ . The horizontal conveyance path of the recording sheet is constituted by the air suction belt 66 and the like including the paper feeding section 60, and from the fixing device 70 to the vertical conveyance path 8 having a conveyance roller.
0 is provided. The recording sheet S is provided on the vertical conveyance path 8
It is discharged from 0 to the upper surface of the printer body 1.

The printing operation of the full color printer will be described below. When the printing operation is started, the photoconductor drum 10 moves in the direction of arrow a and the intermediate transfer belt 4
0 is rotationally driven in the direction of arrow b at the same peripheral speed, and the photosensitive drum 10 is charged to a predetermined potential by the charging brush 11.

Subsequently, the cyan image is exposed by the laser scanning optical system 20, and an electrostatic latent image of the cyan image is formed on the photosensitive drum 10. This electrostatic latent image is immediately developed by the developing device 31C, and the toner image is transferred onto the intermediate transfer belt 40 at the primary transfer portion T ₁ . Immediately after the completion of the primary transfer, the developing device 31M is switched to the developing section D, and subsequently, the exposure, development and primary transfer of the magenta image are performed. Thereafter, similarly, switching to the developing device 31Y, exposure, development, and primary transfer of the yellow image are performed. Further, the developing device 31B
Switching to k, exposure of a black image, development, and primary transfer are performed, and a toner image is superimposed on the intermediate transfer belt 40 for each primary transfer.

When the final primary transfer is completed, the recording sheet S is sent to the secondary transfer portion T ₂ , and the intermediate transfer belt 40
The full-color toner image formed above is transferred onto the recording sheet S. When this secondary transfer is completed, the recording sheet S is conveyed to the fixing device 70, the full-color toner image is fixed on the recording sheet S, and is discharged onto the upper surface of the printer body 1.

The present invention will be described below with reference to specific examples. (Production Example of Hydrophobic Titania A) While mixing and stirring titania (anatase type titania; STT30: manufactured by Titanium Industry Co., Ltd.) having an average primary particle size of 50 nm in an aqueous system, n-hexyltrimethoxysilane is converted to titania in terms of solid content. Of 20% by weight, and the mixture was dried and crushed to obtain hydrophobized titania.

Then, a fluorine-based silane coupling agent (3,
3,4,4,5,5,5,6,6,7,7,8,8,10,10,10-
While stirring a solution of heptadecafluorodecyltrimethoxysilane) dissolved in tetrahydrofuran, titania was gradually added so that the amount of titania was 5% by weight.
The mixture was heated and dried, and then crushed to obtain hydrophobic titania A having a hydrophobicity of 70%.

(Production Example of Hydrophobic Titania B) Average primary particle size 5
While mixing and stirring 0 nm titania (anatase type titania; STT30: manufactured by Titanium Industry Co., Ltd.) in an aqueous system, n-octyltrimethoxysilane was added and mixed so as to be 15% by weight of titanium in terms of solid content, and dried. -Crushing to obtain hydrophobic titanium B having a hydrophobicity of 40%.

Then, a fluorine-based silane coupling agent
While stirring a solution of (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyltrimethoxysilane) dissolved in tetrahydrofuran, 5 wt. The titania was gradually added so that it became%. This mixture was heated and dried, and then crushed to obtain hydrophobic titania B having a hydrophobicity of 50%.

(Production Example of Hydrophobic Titania C) Titania having an average primary particle size of 15 nm (rutile type MT150A: manufactured by Teika)
Dimethylpolysiloxane (25 ° C for 100 parts by weight)
The viscosity was 500 centistokes) was spray-coated with a solution diluted with 50 parts by weight of xylene.
After drying, the resulting titania is crushed to give a hydrophobicity of 60%.
Hydrophobic titania C was obtained.

(Production Example of Hydrophobic Titania D) Titania having an average primary particle size of 200 nm (anatase type titania; KA-3
0: 100 parts by weight of Titanium Industry Co., Ltd.) and 2 parts by weight of dimethylpolysiloxane (having a viscosity of 500 centistokes at 25 ° C.) were spray-coated with a solution diluted with 50 parts by weight of xylene. After drying, the resulting titania was crushed to obtain a hydrophobic titania D having a hydrophobicity of 20%.

The degree of hydrophobicity and particle size of titania were measured as follows. (Measurement of Hydrophobicity) Put 50 ml of pure water in a 200 ml beaker and add 0.2 g of sample. While stirring the beaker, methanol dehydrated with anhydrous sodium sulfate was added from a buret, and the point at which almost no sample was seen on the liquid surface was taken as the end point, and the amount of methanol required was calculated by the following formula: Hydrophobicity = [Methanol usage / The degree of hydrophobicity was calculated by (50 + amount of methanol used)] × 100.

(Titania Particle Size) Scanning Electron Microscope JSM
The sample was observed with -840A (manufactured by JEOL Ltd.), and the average major axis of the titania particles was defined as the average primary particle size.

(Production of Polyester Resin A) A 2-liter four-necked flask was equipped with a reflux condenser, a water separator, a nitrogen gas introduction tube, a thermometer, and a stirrer, and was installed in a mantle heater to obtain polyoxypropylene ( 2,2) -2,2-bis (4-hydroxyphenyl) propane (PO), polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane (EO) and terephthalic acid (TPA) ),
The mixture was charged so that the molar ratio was 3: 7: 9, and the reaction was carried out by heating and stirring while introducing nitrogen into the flask. The progress of the reaction was traced while measuring the acid value, and when the acid value reached a predetermined value, the reaction was terminated and polyester resin A was obtained.

(Production of Polyester Resin B) In the production of polyester resin A, polyoxypropylene (2,2)
-2,2-bis (4-hydroxyphenyl) propane (P
O), polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane (EO), terephthalic acid (TP
A) and trimellitic acid (TMA) in a molar ratio of 3: 7:
A polyester resin B was obtained in the same manner as in the production of the polyester resin A except that it was used at 8: 1.

Table 1 summarizes the molar ratio of alcohol to acid used in the production of the polyester resins A and B and the acid value of the obtained resin.

[0066]

[Table 1]

The acid value was measured as follows. 10 g of resin was weighed and dissolved in 50 ml of toluene.
Titrated with a pre-standardized N / 10 potassium hydroxide / alcohol solution using a mixed indicator of 0.1% bromthymol blue and phenol red, and the acid value was calculated from the consumption amount of N / 10 potassium hydroxide / alcohol as follows. It calculated according to the formula of. Acid value = 5.61 (mg) × KOH (ml) × N / resin amount (g)

The number average molecular weight (Mn), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) and glass transition point (Tg) of the obtained polyester resin are shown in Table 2 below.
Summarized in.

[0069]

[Table 2]

The molecular weight and glass transition point were measured as follows. As the (molecular weight) measuring device, gel permeation chromatography (807-IT type: manufactured by JASCO Corporation) was used. The temperature of the column was kept at 40 ° C., tetrahydrofuran as a carrier solvent was allowed to flow at 1 kg / cm ² , 0.5 ml of a solution prepared by dissolving 30 mg of a sample in 20 ml of tetrahydrofuran was introduced together with the carrier solvent, and the molecular weight was calculated by polystyrene conversion.

A differential scanning calorimeter (DSC-200: manufactured by Seiko Denshi KK) was used as the (glass transition point) measuring device. A 10 mg sample was precisely weighed and placed in an aluminum pan. As a reference, alumina in an aluminum pan was used. Room temperature to 200 at a temperature rising rate of 30 ° C / min
The temperature is raised to 0 ° C and then cooled, and the temperature rise rate is 10 ° C / min.
The measurement is carried out between 120 ° C. 30-80 in this temperature rising process
The shoulder value of the main endothermic peak in the range of ° C was taken as the glass transition point Tg.

Example 1 Polyester resin A and a cyan pigment (CI Pigment Blue 15-3: manufactured by Toyo Ink Mfg. Co., Ltd.) were charged in a pressure kneader so that the resin: pigment ratio was 7: 3 (weight ratio). ,
Kneaded The kneaded product was pulverized with a feather mill to obtain a pigment master batch.

Polyester resin A 93 parts by weight Pigment masterbatch 10 parts by weight Charge control agent (zinc salicylate complex: E-84: manufactured by Orient Chemical Co.) 2 parts by weight

After mixing the above materials with a Henschel mixer, the mixture was kneaded with a twin-screw extrusion kneader. The obtained kneaded product was cooled, coarsely pulverized with a feather mill, finely pulverized with a jet mill, and further classified to obtain toner particles having a volume average particle diameter of 8.0 μm.

To the obtained toner particles, 0.8% by weight of hydrophobic silica (H1303: manufactured by HDK) and 1.0% by weight of hydrophobic titania A as external additives were added and mixed by a Henschel mixer to obtain a toner. Obtained.

Example 2 Polyester resin B was used in place of polyester resin A, magenta colorant (CI Pigment Red 184: Dainippon Ink and Chemicals, Inc.) was used in place of cyan colorant, and Hydrophobic silica as an additive (H1303: HD
A toner was obtained in the same manner as in Example 1 except that 0.4% by weight of K) and 1.0% by weight of hydrophobic titania B were used.

Example 3 A toner was obtained in the same manner as in Example 1 except that only 1.5% by weight of hydrophobic titania A was used as an external additive.

Example 4 Polyester resin A 100 parts by weight Carbon black (Mogal L: manufactured by Cabot) 3 parts by weight Charge control agent (zinc salicylate complex: E-84: manufactured by Orient Chemical Co.) 2 parts by weight

After mixing the above materials with a Henschel mixer, the mixture was kneaded with a twin-screw extrusion kneader.

After the obtained kneaded product was cooled, it was roughly pulverized with a feather mill. The coarsely pulverized material is finely pulverized with a jet mill,
Further classification was performed to obtain toner particles having a volume average particle diameter of 8.0 μm.

To the obtained toner particles, 1.0% by weight of hydrophobic titania A as an external additive was added and mixed by a Henschel mixer to obtain a toner.

Comparative Example 1 A toner was obtained in the same manner as in Example 2 except that only 1.0% by weight of hydrophobic titania C was used as an external additive.

Comparative Example 2 A toner was obtained in the same manner as in Example 2 except that only 1.0% by weight of hydrophobic titania B was used as an external additive.

[0084]

[Evaluation]

(Heat-resistant storage property) When 5% of toner was put in a glass bottle and left in an environment of 60 ° C. for 5 hours, toner coagulation occurred ×, small occurrence but practically no problem Δ, toner cohesion The ones that can't be seen were marked as ○.

For the following evaluations, images were printed using the full-color printer shown in FIG. 1 and evaluated. (Agglomeration and sticking property) In the initial stage of image formation and after printing 3000 sheets, no toner agglomeration or sticking occurred on the toner regulating blade, ○, a slight occurrence, but no problem in practical use, Δ, toner The case where sticking occurred and there was a problem in practical use was marked with x.

(Cutout) In the initial stage of image output and after printing 3000 sheets, no white spots (cutout) occurred in the image at all. Those with no problems above were rated as Δ, and those with many hollows and problems in practical use were rated as x.

(Fog) 25 ° C., 60% environment (NN environment)
Image development was performed on the developer after storage for 24 hours and the developer after storage for 24 hours at 30 ° C. and 85% environment (HH environment), and almost no fogging occurred on the image by visual evaluation. The sample was evaluated as ○, the sample with some fog but no problem in practical use was evaluated as Δ, and the sample with a large amount of fog as practically problem was evaluated as ×.

The evaluation results are summarized in Table 3 below.

[Table 3]

[0089]

The one-component developer of the present invention has excellent storability.
Even when used in a pressure transfer type image forming apparatus, particularly a full-color image developing apparatus, it is possible to form an excellent image with no voids, fog, etc., and is also excellent in cohesion resistance and sticking resistance. Further, the one-component developer of the present invention has excellent negative chargeability.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a full-color image forming apparatus.

FIG. 2 is a partially enlarged view of the developing device.

[Explanation of symbols]

10: photoconductor drum, 11: charging brush, 12: cleaner, 20: laser scanning optical system, 30: full-color developing device, 32: developing sleeve, 33: spindle, 34a: blade, 34b: blade, 40: intermediate transfer Belt, 41:
Primary transfer roller, 42: support roller, 43: secondary transfer roller, 60: paper feed section, 61: paper feed tray, 62: paper feed roller, 63: timing roller, 66: air suction belt, 70: fixing device , 80: Vertical transport path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Tamaki 2-3-13 Azuchi-cho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Co., Ltd. 2-3-13 Osaka International Building Minolta Co., Ltd. (72) Inventor Ken Arai 2-3-13 Azuchi-cho, Chuo-ku, Osaka City, Osaka Prefecture Osaka International Building Minolta Co. (72) Inventor Hiroyuki Fukuda Osaka Prefecture 2-13-3 Azuchicho, Chuo-ku, Osaka City Osaka International Building Minolta Co., Ltd.

Claims (3)

[Claims] 1. A one-component developer used in a one-component developing device comprising a developer carrying member and a developer regulating member installed so as to be in pressure contact with or close to the developer carrying member, This developer comprises toner particles containing a binder resin and a colorant, and an external additive externally mixed with the toner particles. The external additive is surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent. A one-component developer comprising anatase-type titania having an average primary particle size of 10 to 90 nm. 2. An image is formed by developing an electrostatic latent image formed on an electrostatic latent image carrier with toner, and pressing and transferring the formed toner image by a transfer roller through a recording paper. A one-component developer for use in an image forming apparatus, the developer comprising toner particles containing a binder resin and a colorant, and an external additive externally mixed with the toner particles. A one-component developer characterized in that the additive comprises anatase type titania having an average primary particle size of 10 to 90 nm which is surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent. 3. A toner image is sequentially formed for each predetermined color on an electrostatic latent image carrier, and the toner image is sequentially transferred onto the intermediate transfer member by a transfer roller through the intermediate transfer member, and the intermediate transfer is performed. A full-color non-magnetic one-component developer used in an image forming apparatus for forming a full-color image by pressing and transferring a toner image superposed on the body through a recording paper by a transfer roller. Is composed of toner particles containing a binder resin and a colorant, and an external additive externally mixed with the toner particles. The external additive is surface-treated with a hydrophobizing agent and a fluorine-based silane coupling agent. A non-magnetic one-component developer comprising anatase-type titania having a primary particle size of 10 to 90 nm.