JPH09281795A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably obtain an excellent toner image being clear of the generation of background fogging, density unevenness or the like on the formed image, by making the adequate quantity of the toner stably transported in a developing area by the developer transporting member while making the toner adequately electrified even under the high temp. and high humidity, in the case of making the transported toner triboelectrified, while controlling a quantity of the toner transported on a developing area, by holding a controlling member in press contact with a surface of the developer transporting member. SOLUTION: This developing device, toriboelectrifiys the toner transported in the developing area, by holding the controlling member 16 in press contact with the surface of the developer transporting member 13 making the toner (t) transported in the area opposing the image carrier 1, while controlling the quantity of the toner transported on the developing area by the developer transporting member by the controlling member. In this case, fine particles layer 14 is formed by making the fine particles 14a of 3 to 30μm whose polarity is opposite to that of the toner uniformly closely stuck thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used for developing a latent image formed on an image bearing member in an image forming apparatus such as a copying machine or a printer, and more particularly, to a developing agent conveying member. When carrying the toner by carrying the toner to the developing area facing the image carrier, a regulating member is brought into pressure contact with the surface of the developer carrying member, so that the toner carrying by the developer carrying member is carried to the developing area by the regulating member. The present invention relates to a developing device in which the amount is regulated and the toner conveyed to the developing area is frictionally charged.

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, various developing devices have been used to develop a latent image formed on an image carrier.

As such a developing device, in addition to a two-component developing type developing device in which a developer contains a carrier and a toner, a one-component developing type developing device using no carrier has been known.

Here, in the developing device of the one-component developing system, in carrying out the development by carrying the toner by the developer carrying member to the developing area facing the image carrier,
It is widely used that a regulating member is brought into pressure contact with the surface of the developer conveying member, the regulating member regulates the amount of toner conveyed to the developing area by the developer conveying member, and the toner is frictionally charged. It had been.

Here, when the amount of toner conveyed by the developer conveying member is regulated by pressing the regulating member against the surface of the developer conveying member in this way, the toner is on the developer conveying member. There is a problem in that the toner adheres to the sheet and filming occurs, the amount of the developer conveyed by the developer conveying member becomes uneven, and noise such as density unevenness occurs in the formed image.

If the surface roughness of the developer carrying member is too small, the amount of toner carried by the developer carrying member is reduced, and the toner carried by the carrying member is regulated as described above. In that case, the toner charge amount is increased and the occurrence of background fog is suppressed,
There are problems that the density of the formed image is lowered and that the image has uneven density.

On the other hand, if the surface roughness of the developer carrying member becomes too large, the amount of developer carried by the developer carrying member becomes too large, and the toner carried by the regulating member as described above. However, there is a problem that the toner to be conveyed is not sufficiently charged, and the formed image has background fogging and toner scattering around characters.

Therefore, conventionally, fine particles are adhered to the surface of the above-mentioned developer conveying member so as to be coated with nickel electroforming, and as shown in Japanese Patent Laid-Open No. 7-306586, fine particles are used. Is disclosed in which a surface layer is provided on the surface of the developer transport member by dispersing the above in a binder resin.

However, when the fine particles are adhered and coated by nickel electroforming as described above, or the fine particles are dispersed in a binder resin to form a surface layer on the surface of the developer conveying member, the fine particles become the developer conveying member. Since it is not well exposed to the surface of the developer carrying member, it is not possible to impart uniform unevenness to the surface of the developer carrying member. Especially, when developing at high speed, the toner on the developer carrying member is prevented by the regulating member. The amount of the toner cannot be regulated well, and the toner cannot be sufficiently charged by the above-mentioned regulation member. In particular, the toner cannot be sufficiently charged under high temperature and high humidity, and the image still formed. However, there are problems such as density unevenness and noise such as background fog.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a developing device used for developing a latent image formed on an image bearing member in an image forming apparatus such as a copying machine or a printer, which comprises a developer conveying member. A regulating member is pressed against the surface, the regulating member regulates the amount of toner conveyed to the developing region by the developer conveying member, and the toner conveyed to the developing region is triboelectrically charged. The problem is to solve such various problems.

That is, according to the present invention, in the developing device as described above, the regulating member is brought into pressure contact with the surface of the developer conveying member, and the regulating member controls the amount of toner conveyed to the developing area by the developer conveying member. When the toner is regulated and the toner to be conveyed is triboelectrically charged, an appropriate amount of toner is stably conveyed to the developing area by the developer conveying member, and the conveyed toner is appropriately charged. It is an object of the present invention to properly charge a toner even under high temperature and high humidity, to prevent a fog or density unevenness from being formed in an image to be formed and to stably obtain a good image. .

In the developing device according to the present invention, in order to solve the above problems, a regulating member is provided on the surface of a developer carrying member for carrying toner to a developing area facing the image carrier. In the developing device in which the amount of toner conveyed to the developing area by the developer conveying member is regulated by pressure contact and the toner conveyed to the developing area is frictionally charged, the surface of the developer conveying member is The toner and the above-mentioned toner particles having an average particle diameter of 3 to 30 μm are uniformly adhered to each other to form a particle layer.

Here, in the developing device of the present invention, the fine particles having a particle size of 3 to 30 μm are made to adhere to the surface of the developer conveying member. When the unevenness of the surface of the developer transport member becomes small, the amount of toner transported by the developer transport member decreases, and when the amount of toner transported to the development region is regulated by the regulation member as described above, the development region The amount of toner conveyed to the paper is reduced, the density of the formed image is lowered, and density unevenness occurs. On the other hand, when fine particles having an average particle size of more than 30 μm are adhered, the amount of the toner conveyed by the developer conveying member becomes too large, and the toner is not sufficiently charged when regulated by the regulating member as described above. Fogging on the background and toner scattering around characters occur in the formed image.

Then, as in the developing device of the present invention, fine particles having an average particle diameter of 3 to 30 μm and having a chargeability opposite to that of the toner are uniformly adhered to the surface of the developer conveying member to form a fine particle layer. The surface of the developer conveying member has appropriate irregularities, and the developer conveying member conveys an appropriate amount of toner, and the regulating member allows the toner to be appropriately charged. Even under high temperature and high humidity, the toner comes to be charged properly by contacting the particles with the opposite charging property.
Even under high humidity, it is possible to stably obtain a good image without background fog or density unevenness. It is more preferable to use fine particles having an average particle size of 5 to 25 μm as the fine particles to be adhered to the surface of the developer transport member.

Further, when the toner conveyed by the developer conveying member and the shape of the fine particles adhered to the surface of the developer conveying member are close to each other, the toner is sufficiently frictionally charged by the regulating member. However, if the difference in shape between the toner and the fine particles becomes too large, the fine particles adhered to the surface of the developer conveying member will be scraped off when the toner conveyed by the developer conveying member is regulated by the regulating member. Or the toner is damaged,
There are problems that the durability of the developer carrying member is lowered and that ultrafine particles are generated to adversely affect the image formed.

Therefore, in the developing device of the present invention,
When fine particles are adhered to the surface of the developer transport member as described above, the value A of the shape factor SF-1 of the toner used for development and the value B of the fine particle shape factor SF-1 are 10 ≦.
| AB | ≦ 80, more preferably 15 ≦ | AB | ≦
Try to be 70.

Here, regarding the values A and B of the shape factor SF-1 in the toner and the fine particles, an image analyzer (manufactured by Nippon Regulator Co .; Luzex 500) is used.
0) was used to measure the average value L of the maximum lengths and the average value S of the projected areas in each projected image of toner and fine particles, and each shape factor SF-1 was obtained by the following formula. SF-1 = (L ² / S) × (π / 4) × 100 The shape factor SF-1 is used as a parameter indicating the difference between the major axis and the minor axis of the particle, and indicates the sphericity of the particle, The closer the particle shape is to the sphere, the closer the value to 100.

Further, in the developing device of the present invention, resin fine particles or inorganic fine particles can be used as the above-mentioned fine particles adhered to the surface of the developer conveying member.

When a negatively chargeable toner is used in this developing device, fine particles having a chargeability opposite to that of the toner, that is, a positive chargeability, are, for example, acrylic resin, benzoguanamine resin, nylon resin, polyimide resin, polyamide. Fine particles composed of a thermoplastic resin such as a resin or a thermosetting resin can be used, and the resin may contain a positive charge control agent that imparts a positive charge property or a copolymer of a nitrogen-containing monomer. It may be configured. Here, as the above-mentioned positive charge control agent, for example, a nigrosine dye, a quaternary ammonium salt or the like can be used, and as the above-mentioned nitrogen-containing monomer, 2-dimethylaminoethyl acrylate or 2-acrylic acid acrylate can be used. Diethylaminoethyl, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl methacrylate, vinyl pyridine, N
-Vinylcarbazole, vinylimidazole, etc. can be used.

On the other hand, when a positively chargeable toner is used in this developing device, fine particles having a chargeability opposite to that of the toner, that is, a negative chargeability, such as a fluorine resin, a polyolefin resin, a silicone resin, a polyester resin, etc., are used. Fine particles composed of a thermoplastic resin or a thermosetting resin can be used, and a negative charge control agent that imparts negative chargeability can be included in the resin, or a fluorine-containing acrylic monomer or a fluorine-containing methacrylic monomer. You may make it comprise the copolymer of. Here, as the negative charge control agent, for example, a salicylic acid-based or naphthol-based chromium complex, an aluminum complex, an iron complex, a zinc complex, or the like can be used.

As the inorganic fine particles used for the above fine particles, for example, magnetic powder, ferrite particles, alumina particles, aluminum powder, zinc powder, iron powder, silica particles, glass beads, titanium particles and the like can be used. Alternatively, the surface of these inorganic fine particles may be surface-treated with a silane coupling agent, a titanium coupling agent, silicone oil, or the like. Surface treatment with an amino group-containing coupling agent is preferable, and surface treatment with a fluorine group-containing coupling agent is preferable when imparting negative chargeability.

On the other hand, as the toner used in the developing device of the present invention, a known toner containing at least a binder resin and a colorant can be used.

The binder resin used in the toner has a glass transition point Tg lower than 55 ° C.
While there is a problem in the storage stability of the toner, when the temperature is higher than 75 ° C., the fixing property to transfer paper and the like decreases, so the glass transition point Tg is 55 to 75 ° C., preferably 58 to 68 ° C.
Use a resin at ℃. Also, its softening point is 80
If the temperature is lower than 70 ° C, the storage stability of the toner will be problematic, while if it is higher than 170 ° C, the fixability will be problematic. Therefore, use a resin having a softening point of 80 to 170 ° C, preferably 90 to 150 ° C. .

As such a binder resin, a known resin conventionally used in toner can be used, and preferably a polyester resin or a urethane-modified polyester resin is used.

As the colorant used in this toner, a colorant generally used in toners can be used.

Here, as the black colorant, for example, carbon black, copper oxide, manganese dioxide, aniline black, activated carbon or the like can be used alone or in combination of two or more kinds, and as the full color yellow colorant, for example, , Yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral first yellow, nickel titanium yellow, navels yellow, naphthol yellow S, banza yellow G, banza yellow 10G, benzine yellow G, benzine yellow GR, quinoline yellow Lake, permanent yellow NCG, tartrazine lake, etc. can be used, and examples of red colorants include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, balkan orange, benzidine orene. G, Permanent Red 4R,
Lake Red D or the like can be used, and as the blue colorant, for example, dark blue, cobalt blue, phthalocyanine blue, Victoria blue lake or the like can be used.

The amount of these colorants contained in the toner is 1 to 20 parts by weight, preferably 3 to 15 parts by weight, based on 100 parts by weight of the binder resin.

In addition to the binder resin and the colorant, a charge control agent, an offset preventing agent, a fluidizing agent, etc. may be added to the above-mentioned toner, if necessary.

Here, when the charge control agent is added to the toner, examples of the positive charge control agent that imparts positive chargeability to the toner include nigrosine dye, quaternary ammonium salt,
A polyamine compound, an imidazole compound or the like can be used. On the other hand, examples of the negative charge control agent that imparts negative chargeability to the toner include chromium complex salt type azo dyes, copper phthalocyanine type dyes, chromium complex salts, zinc complex salts, and aluminum. Complex salts and calex allene compounds can be used. When adding these charge control agents to the toner, 0.5 to 8 weight parts, preferably 1 to 5 weight parts of the charge control agent should be added to 100 weight parts of the binder resin in the toner. To

As the anti-offset agent, for example, low molecular weight polyolefin wax, low molecular weight oxidation type polyolefin wax, carnauba wax, sazol wax, candelilla wax, jojoba oil wax, etc. may be used alone or in combination of two or more kinds. The offset preventive agent can be used in an amount of 0.1 to 6 parts by weight, preferably 2 parts by weight, based on 100 parts by weight of the binder resin in the toner.
It is preferable to use the offset preventive agent having a softening point of 70 to 150 ° C. and an acid value of 1 to 40 as the offset preventing agent.

As the fluidizing agent, for example, inorganic fine particles such as silica fine particles, titanium dioxide fine particles, alumina fine particles, magnesium fluoride fine particles, and silicon carbide fine particles can be used. These fine particles are used as a silane coupling agent. It is preferable to use a material having a hydrophobicity of 20 to 80% after being hydrophobized with a titanium coupling agent, silicone oil or the like. As the fluidizing agent, various resin fine particles having an average particle diameter of 0.1 to 1 μm obtained by emulsion polymerization, soap-free emulsion polymerization, non-aqueous dispersion polymerization, etc. can be used. The amount of such a fluidizing agent added is 0.05 to 3 parts by weight, preferably 0.1 to 100 parts by weight of the toner.
Add 2 parts by weight.

Further, in the above toner, if the volume average particle diameter is too large, the reproducibility of a high-definition image is deteriorated. On the other hand, if the volume average particle diameter is small, fine powder is produced during the production by the pulverization method. Content is large, which is inconvenient in terms of productivity and cost.
μm, preferably 6 to 10 μm, and in this toner, the number distribution of toner having a particle size of 4 μm or less is 40% or less, preferably 30% or less, and the volume distribution of toner of 20 μm or more. Is preferably 1% or less.

[0031]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a developing device according to an embodiment of the present invention.

Here, in the developing device in this embodiment, as shown in FIG. 1, along the axial direction of the image carrier 1 in which the photosensitive layer 1b is formed on the surface of the cylindrical conductive substrate 1a,
The toner is accommodated in a toner accommodating portion 11 of the apparatus main body 10 which is provided so as to face the image bearing member 1 and is separated from the image bearing member 1, and the toner feeding unit is provided in the toner accommodating portion 11. The member 11a is rotated so that the toner t accommodated in the toner accommodating portion 11 is sent to the toner supply portion 12 located on the image carrier 1 side of the toner accommodating portion 11.

A rotating toner supply member 12a is provided in the toner supply unit 12, and the toner t in the toner supply unit 12 is supplied to the developer conveying member 13 by the toner supply member 12a. There is.

Here, in the developing device in this embodiment, as the developer transport member 13, a driving roller 13a that is rotationally driven is provided so as to face the image carrier 1 in the axial direction, and This drive roller 13
Developing sleeve 1 having an inner diameter slightly larger than the outer diameter of a
3b is provided on the outer peripheral side of the driving roller 13a, and as shown in FIG. 2, the surface of the developing sleeve 13b has an average particle size in the range of 3 to 30 .mu.m and is oppositely charged to the toner t. The fine particle layer 1 by adhering the fine particles 14a of
4 is formed.

Then, pressing guides 15 are provided on both ends of the developing sleeve 13b on the side opposite to the image carrier 1, and the developing sleeves 13b are driven by the pressing guides 15 on the side opposite to the image carrier 1 to drive roller 13a. The developing sleeve 13b is pressed against the outer peripheral surface so that the developing sleeve 13b is driven by the rotation of the driving roller 13a, and the developing sleeve 13b is driven by the driving roller 13a in the developing area facing the image carrying body 1. The developing sleeve 13b is projected to the first side so that the developing sleeve 13b is brought into soft contact with the surface of the image carrier 1.

Further, at the portion where the developing sleeve 13b is in contact with the driving roller 13a as described above, the regulating member 16 is brought into pressure contact with the surface of the developing sleeve 13b, and the developing is driven by the rotation of the driving roller 13a. The amount of toner t conveyed to the image carrier 1 side by the sleeve 13b is regulated by the regulation member 16, and the toner t is triboelectrically charged.

The toner t, which is regulated by the regulating member 16 and frictionally charged in this manner, is applied to the developing sleeve 13b.
Is carried to a developing area in contact with the image carrier 1 for development.

Here, as in this developing device, the toner t having an average particle diameter of 3 to 30 μm and the particles 14a having an opposite charging property are uniformly adhered to the surface of the developing sleeve 13b, and the particle layer is formed on the surface of the developing sleeve 13b. When the developing sleeve 14 is formed, the surface of the developing sleeve 13b has a uniform and appropriate irregularity, and the developing sleeve 13b conveys an appropriate amount of toner t, and the regulating member 16 conveys the toner t to the developing area. Is appropriately regulated, and the toner t is pressed by the regulation member 16 and comes into contact with the oppositely charged fine particles 14a, so that the toner t
Is properly charged even under high temperature and high humidity.

Next, a case will be described in which an electrostatic latent image formed on the image carrier 1 is developed by using the developing device of this embodiment to form an image.

First, a predetermined voltage is applied to the charging brush 2 from the power source 2a, the surface of the image carrier 1 is charged to a predetermined surface potential by the charging brush 2, and the image carrier 1 thus charged is charged. Suitable exposure means for the surface (not shown)
Is used to form an electrostatic latent image on the surface of the charged image carrier 1.

Next, the toner t is conveyed to the image carrier 1 side by the developing sleeve 13b provided in the developing device as described above, and the amount of the toner t conveyed by the developing sleeve 13b is adjusted by the regulating member 16 described above. The toner t is charged while being regulated by, and the toner t charged in this manner is conveyed by the developing sleeve 13b to the developing area in contact with the image carrier 1, and the image carrier on which the electrostatic latent image is formed as described above. The toner t is supplied to the surface of the body 1 to form a toner image on the surface of the image carrier 1.

The toner t remaining on the developing sleeve 13b without being supplied to the image carrier 1 from the developing sleeve 13b is passed through the seal member 17 provided in the developing device by the developing sleeve 13b to the inside of the apparatus main body 10. Then, the toner is returned to the above-mentioned toner supply section 12.

On the other hand, for the toner image formed on the surface of the image carrier 1 as described above, the recording paper 3 is guided between the image carrier 1 and the transfer roller 4, and the transfer roller 4 is supplied with the power source 4a. A bias voltage having a polarity opposite to the charging polarity of the toner t is applied to transfer the toner image formed on the image carrier 1 onto the recording paper 3, and the recording paper 3 thus transferred with the toner image is fixed on the fixing roller. Then, the transferred toner image is fixed on the recording paper 3 to form an image.

Here, when the electrostatic latent image formed on the image carrier 1 is developed using the developing device in this embodiment, the developing sleeve having the fine particle layer 14 formed on the surface as described above. 13b conveys an appropriate amount of toner t, the regulation member 16 regulates the amount of toner t to be conveyed to the developing area appropriately, and the toner t is appropriately charged even under high temperature and high humidity. As described above, a proper amount of the appropriately charged toner t is stably guided to the developing area facing the image carrier 1 and used for development, and fog occurs in an image formed. In addition, a sufficient amount of the toner t is supplied to the image carrier 1, and the density of the formed image does not decrease and the density unevenness does not occur, and a good image is stable. do it It is as to become.

In the developing device of the above embodiment, the driving roller 13a is used as the developer carrying member 13 for carrying the toner t to the developing area facing the image carrier 1.
Although the developing sleeve 13b driven by is used, the developer carrying member 13 is not limited to the above-described one, and various developing rollers made of metal or rubber can be used.

[0046]

EXAMPLES Next, specific examples in which the types of the toner t to be used and the fine particles 14a to be adhered to the surface of the developing sleeve 13b are changed in the developing device in the above-described embodiment will be described, and a comparative example will be described. It will be clarified that the developing device in this embodiment is excellent.

(Embodiment 1) In the developing device in this embodiment, as the toner t, the negatively charged toner t manufactured as described below is used.

Here, in producing the toner t, a low molecular weight polyester resin produced as described below and a polyester resin to be polymerized are used as the binder resin.

First, in order to obtain a low molecular weight polyester resin, a 5-liter four-necked flask equipped with a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer was installed in a mantle heater, In this four-necked flask, 1100 g of bisphenol propylene oxide adduct, 150 g of bisphenol ethylene oxide adduct, 290 g of isophthalic acid, 1 terephthalic acid were added.
95 g were added, dehydration polycondensation was carried out at a temperature of 250 ° C. while introducing nitrogen gas into the flask, and the glass transition point T
A low molecular weight polyester resin having a g of 66.7 ° C. was obtained.

On the other hand, in order to obtain a polyester resin to be polymerized, a four-necked flask is installed in a mantle heater in the same manner as in the case of the above-mentioned low molecular weight polyester resin, and bisphenol propylene is placed in this four-necked flask. 1500 g of oxide adduct, 915 g of isophthalic acid, 95 g of succinic acid, 185 g of diethylene glycol and 95.6 g of glycerin were added, and dehydration polycondensation was performed at a temperature of 240 ° C. while introducing nitrogen gas into the flask, and glass transition. A polymerized polyester resin having a point Tg of 32 ° C. was obtained.

Next, 3800 parts by weight of the low-molecular-weight polyester resin obtained as described above and 1300 parts by weight of the polyester resin to be polymerized were charged into a Henschel mixer to make them sufficiently uniform. Stir until
After that, these are put into a heating kneader, 120 parts by weight of diphenylmethane-4,4-diisocyanate is added thereto, and these are reacted by a heating kneader at a temperature of 120 ° C. for 1 hour to polymerize a polyester resin to be polymerized. Then, it was confirmed by measuring the NCO% that the remaining free isocyanate groups were almost gone, and this was cooled to obtain a polyester resin having a urethane bond. The polyester resin thus obtained has a glass transition point Tg of 64.8 ° C. and a softening point Tm of 1
The temperature was 51 ° C., the acid value was 27.3 KOH mg / g, and the melt index MI value was 3.3 (150 ° C./10 min).

Then, the above polyester resin is added to 100
Parts by weight, carbon black as a coloring agent (manufactured by Degussa: Sp
5 parts by weight of the organic black 6) and 3.5 parts of a negative charge control agent (Bontron S-34 manufactured by Orient Chemical Co.).
By weight, oxidized low molecular weight polypropylene (manufactured by Sanyo Kasei Kogyo Co., Ltd .: Viscole TS-200) is adjusted to 1.0 part by weight, and carnauba wax (produced by Kato Yoko Co., Ltd.) is adjusted to 1.5 parts by weight, and these are mixed by a Henschel mixer. After thoroughly mixing, this was kneaded with a twin-screw extrusion kneader, and the kneaded product was allowed to cool and then coarsely pulverized, and then finely pulverized with an ultrasonic jet pulverizer (manufactured by Nippon Pneumatic Co., Ltd.). Crush,
Then, this was classified by a classifier (Matsuzaka Trading Co., Ltd .: Elbow Jet) to obtain toner particles having a volume average particle size of 8.0 μm. In this toner particle, particles having a particle diameter of 4 μm or less were 18.6% by number, 20 μm
Particles of m or more were 0.2% by volume.

Next, 0.5% by weight of hydrophobic silica (Taranox 500 manufactured by Tarco Co., Ltd.) was added to the above toner particles, and these were mixed and stirred by a Henschel mixer to treat the surface with the hydrophobic silica. A negatively chargeable toner was obtained. The value A of the shape factor SF-1 of this toner is 1
85.

On the other hand, in the developing device of this embodiment,
Fine particles 1 adhered to the surface of the developing sleeve 13b.
As 4a, positively charged fine particles 14a produced as described below were used.

In producing the fine particles 14a, 60 parts by weight of styrene monomer, 35 parts by weight of n-butyl methacrylate monomer, and 2 parts of methacrylic acid are used.
5 parts by weight of dimethylaminoethyl monomer and 0.2 parts by weight of azobisisobutyronitrile as a polymerization initiator, put them in a 3 liter four-neck flask, and cool to this four-neck flask under reflux. Attach a vessel, nitrogen gas inlet tube, thermometer, and stirrer, and add 1 liter of deionized water sodium dodecylbenzene sulfonate to 1 liter of deionized water.
% By weight and dispersion stabilizer (polyvinyl alcohol polymerization degree 50
0.5% by weight of 0) was added, and the mixture was stirred for 15 minutes at a rotation speed of 4000 rpm using the above stirring device (TK Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), and then under a nitrogen atmosphere, Polymerization reaction was carried out at 70 ° C. for 6 hours while stirring at a rotation speed of 200 rpm.

After the completion of the polymerization reaction, the obtained polymer was filtered, washed with water, dried and then classified with the above classifier (Matsuzaka Trading Co., Ltd .: Elbow Jet).
Positively charged fine particles having an average particle size of 6.5 μm were obtained. The value B of the shape factor SF-1 of the fine particles is 12
It was one.

Then, a 1% diluting solution of an adhesive (Sumitomo 3M: Design Bond S) is applied to the surface of the developing sleeve 13b, dried, and then the positively charged fine particles 14a are applied. It is adhered to the surface of the developing sleeve 13b, and then the excess fine particles 1
4a was removed, and as shown in FIG. 2, the fine particle layer 14 was formed by uniformly adhering the fine particles 14a to the surface of the developing sleeve 13b.

(Embodiment 2) In this embodiment, only the developing device of Embodiment 1 and the fine particles 14a to be adhered to the surface of the developing sleeve 13b are changed, and a positively chargeable material manufactured as follows is produced. The fine particles 14a were used, and otherwise the same as in the case of Example 1 above.

In this Example, 100 parts by weight of a styrene-acrylic resin (FB-1157 manufactured by Mitsubishi Rayon Co., Ltd.) and a positive charge control agent (Bontron manufactured by Orient Chemical Co., Ltd.) were used to manufacture the fine particles 14a. P
-53) in a proportion of 5 parts by weight, and these were mixed and dispersed in a 9-liter Henschel mixer at 3000 rpm for 3 minutes, and then kneaded by a twin-screw extrusion kneader, and the kneaded product was left to cool. After that, coarsely pulverize this with a feather mill, and further finely pulverize with the ultrasonic jet pulverizer (manufactured by Nippon Pneumatic Co., Ltd.), classify it with a classifier (Hosokawa Micron Co., Ltd .: Super Separator), and average. Particle size 5.6 μm and shape factor SF-
Positively charged fine particles having a value B of 1 of 158 were obtained.

(Embodiment 3) In the developing device in this embodiment, the negatively charged toner t manufactured as follows is used.

Here, in producing the toner t, 100 parts by weight of a polyester resin (manufactured by Mitsubishi Rayon Co., Ltd .: Diacron 684), 4 parts by weight of copper phthalocyanine as a colorant, a negative charge control agent (Orient Chemical Co., Ltd.) were used. Made: Bontron E-84) at a ratio of 5 parts by weight,
3000 rp in a liter Henschel mixer
After mixing and dispersing at m for 2 minutes, this was kneaded with a twin-screw extrusion kneader, and the kneaded material was left to cool, then coarsely crushed with a feather mill, and further kryptron (manufactured by Kawasaki Heavy Industries Ltd.). ), Followed by classification with the above classifier (manufactured by Hosokawa Micron Co., Ltd .: Super Separator) to obtain toner particles having a volume average particle size of 10.3 μm. The toner particles have a particle size of 4 μm.
The following particles are 7.5% by number, and the particles having a particle size of 20 μm or more are 0.
It was 5% by volume.

Then, 1% by weight of hydrophobic titanium (T-805 manufactured by Nippon Aerosil Co., Ltd.) was added to the toner particles, and these were mixed with a Henschel mixer at 3000 rpm.
For 3 minutes, and then hydrophobic silica (manufactured by Tarco:
0.4% by weight of Talanox 500) was added, and these were mixed and stirred by a Henschel mixer at 2500 rpm for 90 seconds to obtain a negatively chargeable toner having the surface treated with hydrophobic titanium and hydrophobic silica. The value A of the shape factor SF-1 of this toner was 148.

On the other hand, as the positively chargeable fine particles 14a adhered to the surface of the developing sleeve 13b, an average particle diameter obtained by classifying alumina powder (AO-500 manufactured by Admatex Co.) is 5.1 μm. Fine particles obtained by treating 3% by weight of γ-aminopropyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) with respect to alumina particles having a shape factor SF-1 value B of 108 were used.

(Embodiment 4) In the developing device in this embodiment, the negatively charged toner t manufactured as follows is used.

Here, in manufacturing the toner t, a polyester resin (manufactured by Toyobo Co., Ltd .: Byron 20) is used.
20), 5 parts by weight of carbon black (Cabot Corporation: Mogul L) as a colorant, and 2.5 parts of a negative charge control agent (Orient Chemical Co., Ltd .: Bontron S-34).
Parts by weight, oxidized low molecular weight polypropylene (manufactured by Sanyo Kasei Co., Ltd .: Viscole TS-200) in a ratio of 1.0 parts by weight, and dissolved in a mixed solvent having a ratio of 50 parts by weight of toluene and 15 parts by weight of methyl ethyl ketone. Or evenly disperse it, put it in a 3 liter beaker, and add 2 liters of ion-exchanged water with 0.3 wt% of sodium dodecylbenzenesulfonate as a dispersant and 1 wt% of polyvinyl alcohol. Put a thermometer, attach a thermometer and a stirring device to this beaker,
These were stirred for 15 minutes at a rotation speed of 7,000 rpm using the above stirring device (TK Homomixer manufactured by Tokushu Kika Kogyo Co., Ltd.), and then the mixed solvent was removed while further stirring at a rotation speed of 200 rpm.

After that, this was filtered, washed with pure water 3 to 5 times, dried under reduced pressure and classified to have a volume average particle size of 7.
Toner particles having a size of 1 μm were obtained. In this toner particle, particles having a particle diameter of 4 μm or less were 20.5% by number, and particles having a particle diameter of 20 μm or more were 0% by volume.

Hydrophobic silica (R-974 manufactured by Nippon Aerosil Co., Ltd.) was added to the toner particles in a proportion of 0.5% by weight, and these were treated with a Henschel mixer for 90 seconds at 2500 rpm to be negatively charged. Toner was obtained. The value A of the shape factor SF-1 of this toner is 1
35.

On the other hand, as the fine particles 14a adhered to the surface of the developing sleeve 13b, the same positively chargeable fine particles 14a as those used in the first embodiment are used.

(Embodiment 5) In the developing device in this embodiment, the negatively charged toner t manufactured as follows is used.

Here, in manufacturing the toner t, 70 parts by weight of a styrene monomer, 30 parts by weight of an n-butyl methacrylate monomer, carbon black as a colorant (Raven 125 manufactured by Columbia Carbon Co., Ltd.) are used.
5) 6 parts by weight, a negative charge control agent (manufactured by Orient Chemical Co., Ltd .:
3 parts by weight of Bontron S-34), 0.5 parts by weight of lauryl peroxide as a polymerization initiator, and 1% by weight of sodium dodecylbenzenesulfonate as a dispersion stabilizer in ion-exchanged water. In addition, the above-mentioned stirring device (made by Tokushu Kika Kogyo Co., Ltd .: TK homomixer)
After stirring for 15 minutes at a rotation speed of 6000 rpm, the rotation speed was 150 r under a nitrogen atmosphere at 70 ° C.
The polymerization reaction was carried out for 5 hours while stirring at pm, and then this was filtered, washed with water, dried and classified to obtain toner particles having a volume average particle diameter of 8.5 μm. In addition, in the toner particles, particles having a particle diameter of 4 μm or less are 16.5.
The number% and the particles of 20 μm or more were 0.2% by volume.

Then, 0.4% by weight of hydrophobic silica (Taranox 500, manufactured by Tarco Co., Ltd.) was added to the toner particles, and they were mixed with a Henschel mixer for 2500 r.
It was treated with pm for 90 seconds to obtain a negatively chargeable toner. The value A of the shape factor SF-1 of this toner was 125.

On the other hand, as the fine particles 14a adhered to the surface of the developing sleeve 13b, the same positively charging fine particles 14a as those used in the first embodiment are used.

(Embodiment 6) In the developing device of this embodiment, the same negatively chargeable toner t as that used in the above-mentioned Embodiment 1 is used, and as the fine particles 14a adhered to the surface of the developing sleeve 13b. Was used as positively charged fine particles (Evocolor BP-1004 manufactured by Nippon Shokubai Co., Ltd.) in which carbon black was dispersed in a benzoguanamine resin. The positively chargeable fine particles had an average particle diameter of 4.0 μm and a shape factor SF-1 value B of 104.

(Embodiment 7) In the developing device of this embodiment, the positively charged toner t manufactured as described below was used.

Here, in manufacturing the toner t, a styrene-acrylic resin (made by Mitsubishi Rayon Co .: F
B-1157) 100 parts by weight, colorant carbon black (Cabot Co .: Regal330R) 8 parts by weight, positive charge control agent (Orient Chemical Co., Ltd .: Nigrosine Base EX) 5 parts by weight, anti-offset agent (SANYO). 3.5 parts by weight of Biscol 550P manufactured by Kasei Kogyo Co., Ltd. were mixed and dispersed in a 9 liter Henschel mixer at 3000 rpm for 2 minutes, and then 2
After kneading with a shaft extrusion kneader, the kneaded product is left to cool and then coarsely pulverized with a feather mill, and further finely pulverized with the ultrasonic jet pulverizer (manufactured by Nippon Pneumatic Co., Ltd.). Was classified with the above classifier (Matsuzaka Trading Co., Ltd .: Elbow Jet) to give an average particle size of 8.7 μm.
The obtained toner particles are obtained. In this toner particle, particles having a particle diameter of 4 μm or less are 14.9% by number, 2
Particles of 0 μm or larger accounted for 0.1% by volume.

Then, to the toner particles, a hydrophobic silica (RA-200H manufactured by Nippon Aerosil Co., Ltd.) was added.
4 wt% was added, and these were treated with a Henschel mixer at 3000 rpm for 90 seconds to obtain a positively chargeable toner. The value A of the shape factor SF-1 of this toner
Was 184.

On the other hand, as the fine particles 14a adhered to the surface of the developing sleeve 13b, the negatively chargeable fine particles 14a manufactured as described below are used.

In producing the fine particles 14a, 100 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) and 3.5 parts of a negative charge control agent (Bontron S-34 manufactured by Orient Chemical Co.) are used. Parts by weight, and these were mixed and dispersed in a 9 liter Henschel mixer at 3000 rpm for 3 minutes, and this was mixed with 2 parts.
After kneading with a shaft extrusion kneader, the kneaded product is left to cool, coarsely pulverized with a feather mill, and further finely pulverized with the ultrasonic jet pulverizer (manufactured by Nippon Pneumatic Co., Ltd.), which is then classified. The particles were classified by a machine (manufactured by Hosokawa Micron Co., Ltd .: Super Separator) to obtain negatively charged fine particles having an average particle size of 7.3 μm and a shape factor SF-1 value B of 161.

(Comparative Example 1) In the developing device of this comparative example, the same negatively charging toner t as that used in the above-mentioned Example 1 is used, while the fine particles 14a are adhered to the surface of the developing sleeve 13b. Was manufactured as follows.

Here, in producing the fine particles 14a, 85 parts by weight of a styrene monomer, 10 parts by weight of an n-butyl methacrylate monomer, 5 parts by weight of a divinylbenzene monomer, and azobisisobutyro as a polymerization initiator. The proportion of nitrile was 0.2 parts by weight, and these were placed in a 3-liter four-necked flask, and a reflux condenser, a nitrogen gas introduction pipe, a thermometer, and a stirrer were attached to the four-necked flask, and ion-exchanged water was added. A solution in which 1% by weight of sodium dodecylbenzenesulfonate as a dispersion stabilizer was dissolved was added to 1 liter, and the stirring device (Tokushu Kika Kogyo Co., Ltd .: T
K homomixer) at 15 rpm at 4000 rpm
After stirring for 1 minute, the polymerization reaction was carried out for 5 hours while stirring at 70 ° C. in a nitrogen atmosphere at a rotation speed of 200 rpm.

After the completion of the polymerization reaction, the obtained polymer was filtered, washed with water, dried and classified to obtain fine particles having an average particle diameter of 5.5 μm. The value B of the shape factor SF-1 of the fine particles was 118, and the fine particles had the same negative chargeability as the toner t.

(Comparative Example 2) Also in the developing device of this comparative example, the same negatively chargeable toner t as that used in the above-described Example 1 is used, and as the fine particles 14a to be adhered to the surface of the developing sleeve 13b. Was manufactured as follows.

In producing the fine particles 14a, 100 parts by weight of styrene-acrylic resin (FB-1157 manufactured by Mitsubishi Rayon Co., Ltd.) and styrene-aminoacrylic resin (Lunavale 91 manufactured by Arakawa Chemical Industry Co., Ltd.) are used.
2) in an amount of 5 parts by weight, and these were mixed and dispersed in a Henschel mixer at 2500 rpm for 2 minutes, then kneaded by a twin-screw extrusion kneader, and the kneaded product was left to cool and then Coarsely pulverized and further finely pulverized with the above-mentioned Klyptron (Kawasaki Heavy Industries, Ltd.), and then classified with the above classifier (Hosokawa Micron Co., Ltd .: Super Separator) to obtain an average particle size of 30.5 μm. Fine particles having a coefficient SF-1 value B of 161 were obtained.

(Comparative Example 3) Also in the developing device of this comparative example, the same negatively chargeable toner t as that used in the above-mentioned Example 1 is used, and as the fine particles 14a adhered to the surface of the developing sleeve 13b. In the production of the fine particles 14a in Comparative Example 2, only the conditions for crushing and classifying were changed to obtain fine particles having an average particle diameter of 2.8 μm and a shape factor SF-1 value B of 155.

Here, the above Examples 1 to 7 and Comparative Example 1
Table 3 below shows the particle diameters of the toners t and the fine particles 14a and the values A and B of these shape factors SF-1 used in Examples 1 to 7 and Comparative Examples 1 to 3. The difference | AB | between the value A of the shape factor SF-1 of the toner t and the value B of the shape factor SF-1 of the fine particles 14a is also shown.

[0086]

[Table 1]

Next, the above Examples 1 to 7 and Comparative Examples 1 to
Each developing device of 3 is used under conditions of low temperature and low humidity (L / L) of temperature 15 ° C and humidity 30%, and high temperature and high humidity (H / H) of temperature 35 ° C and humidity 80%. , Images with a black to white ratio (B / W ratio) of 4% were printed at 20 sheets / min, 5000 sheets, 10000 sheets, 20 sheets, respectively.
At each time of 000 sheets, image density, density unevenness, and fog generation in each formed image were evaluated, and toner adhesion to the regulation member 16 was evaluated. The results are shown in Tables 2 to 4 below. Indicated.

In Tables 2 to 4, the image density was evaluated by measuring the reflection density (ID) with a Sakuradensitometer, and measuring the I.D. When D is 1.4 or more, it is indicated by ◯, when 1.2 to 1.4 is indicated by Δ, and when it is 1.2 or less, by X. Further, for the evaluation of density unevenness and fog, the formed image is visually evaluated, and when there is no occurrence of density unevenness and fog, it is good, and when density unevenness and fog occur slightly, but there is no practical problem. Is indicated by Δ, and the case where a large amount of density unevenness or fog is generated, which is a practical problem, is indicated by x. The toner adhesion to the regulation member 16 was evaluated by observing the regulation member 16 with a metallurgical microscope. When the toner adhesion was good, the toner was good, and when the toner adhesion was slightly observed but there was no problem in practical use, the toner adhesion was evaluated. There are many cases where there is a lot of problems, which is a problem in practical use.

[0089]

[Table 2]

[0090]

[Table 3]

[0091]

[Table 4]

As is clear from these results, each of the developments of Examples 1 to 7 in which the average particle diameter is in the range of 3 to 30 μm and the toner t and the oppositely charged fine particles 14a are adhered to the surface of the developing sleeve 13b. In the apparatus, an image having a sufficient image density can be obtained even when 20,000 images are formed, density unevenness and fog are less likely to occur in the formed image, and toner adhesion to the regulating member 16 is also small. Was becoming.

On the other hand, in the developing device of Comparative Example 1 in which the fine particles 14a having the same chargeability as the toner t are used as the fine particles 14a adhered to the surface of the developing sleeve 13b, the toner t on the developing sleeve 13b is changed. Charging could not be performed well, an image having sufficient image density could not be obtained, and density unevenness and fog occurred in the formed image.

Further, in the developing device of Comparative Example 2 in which the fine particles 14a having an average particle diameter larger than 30 μm are adhered to the surface of the developing sleeve 13b, the amount of the toner t conveyed by the developing sleeve 13a becomes large, and the toner t t was not sufficiently charged by the regulation member 16 and fogging occurred in the formed image.

On the other hand, in the developing device of Comparative Example 3 in which the fine particles 14a having an average particle diameter smaller than 3 μm are adhered to the surface of the developing sleeve 13b, the toner t is not easily transported in the developing sleeve 13b, and a sufficient image density is obtained. The obtained image was not obtained, and density unevenness occurred in the formed image.

In comparison with the developing devices of Examples 1 to 7, the toner A used had a shape factor SF-1 of A, and the fine particles 1 adhered to the surface of the developing sleeve 13b.
4a has a difference | AB | with the value B of the shape factor SF-1 of 10
In the smaller developing device of the fifth embodiment, since the difference in shape between the toner t and the fine particles 14a is small, the triboelectrification of the toner t by the regulating member 16 is reduced, and there is no problem in practical use, but the toner is gradually formed. Fogging occurred in the image. On the other hand, in the developing device of Example 6 in which the value of | A−B | is larger than 80, since the difference in shape between the toner t and the fine particles 14a is large, the toner is conveyed by the developing sleeve 13b by the regulating member 16. Of the fine particles 14 adhered to the surface of the developing sleeve 13b when the toner t
The toner “a” was scraped off, the toner “t” was damaged, and the toner adhered to the regulating member 16, so that there was no problem in practical use, but density unevenness and fog occurred in the formed image.

As a result, as in the developing devices of Examples 1 to 4, the shape factor SF-1 of the toner t is A, and the shape factor SF of the fine particles 14a adhered to the surface of the developing sleeve 13b is SF.
It has been found that it is preferable to set the difference | AB | with respect to the value B of −1 within the range of 10 to 80.

[0098]

As described above in detail, in the developing device of the present invention, the regulating member is brought into pressure contact with the surface of the developer conveying member so that the toner conveyed by the regulating member to the developing area can be prevented. While controlling the amount,
When the toner conveyed to the developing area is triboelectrically charged, fine particles having an average particle diameter in the range of 3 to 30 μm are uniformly adhered to the surface of the developer conveying member to form a fine particle layer. As a result, an appropriate amount of toner is conveyed by this developer conveying member, and the toner is appropriately charged due to the regulation by the regulating member described above. By being brought into contact with the fine particles, the particles were properly charged, and a good image free of background fog and density unevenness was stably obtained even under high temperature and high humidity.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a state in which an image is formed using a developing device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a state in which fine particles are uniformly adhered to the surface of a developer conveying member that conveys toner to a developing area facing the image carrier in the developing device in the above embodiment. FIG.

[Explanation of symbols]

 1 Image Carrier 10 Device Main Body 13 Developer Conveying Member 13a Drive Roller 13b Developing Sleeve 14 Fine Particle Layer 14a Fine Particle 16 Regulation Member t Toner

Front page continuation (72) Inventor Shuichi Nakagawa 2-33 Azuchi-cho, Chuo-ku, Osaka Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroshi Goto 2-3-13 Azuchi-cho, Chuo-ku, Osaka Osaka Kokusai Building Minolta Co., Ltd. (72) Inventor Yoichi Fujieda 2-33 Azuchi-cho, Chuo-ku, Osaka Osaka Kokusai Building Minolta Co., Ltd. (72) Inventor, Main tax Tsutsui 2-3-13 Azuchi-cho, Chuo-ku, Osaka No. Osaka International Building Minolta Co., Ltd.

Claims (1)

[Claims] 1. A regulating member is brought into pressure contact with the surface of a developer conveying member that conveys toner to a developing region facing the image carrier, and the regulating member regulates the amount of toner conveyed to the developing region by the developer conveying member. In the developing device that regulates and frictionally charges the toner conveyed to the developing area, the average particle diameter is 3 to 30 on the surface of the developer conveying member.
A developing device characterized in that a fine particle layer having a thickness of μm and having the opposite charging property to the toner is uniformly adhered to form a fine particle layer.