JPH05216275A - Developer, developing device using the same and for production of the same - Google Patents

Abstract

PURPOSE:To obtain a stable image by using a developer, in which the quantity of charge is not increased even in the case of a small particle diameter of the toner particle. CONSTITUTION:In a developing by allowing a toner 11 held on a developing roller 3 to come into contact with a photosensitive drum 4 after charged by a blade 9, if shape factor R of the toner particle is the diameter of a circle having the same area as the projected area of the particle or the diameter of a circle having the same circumferential length as the projected circumferential length of the particle, the relation of R>=1.3 is satisfied and the chargeable quantity of the toner 11 is limited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer which develops upon contact with an electrostatic latent image on a photosensitive drum such as an electrophotographic device or an electrostatic recording device, a developing device using this developer, and this developing device. The present invention relates to a method for producing an agent.

[0002]

2. Description of the Related Art As a developing method for visualizing an electrostatic latent image,
At present, the electrophotographic method and the electrostatic recording method are widely used. Among them, colored particles called toner,
A two-component developing method is mainly used in which magnetic particles called carriers are mixed, an electric charge is applied to the toner, a developer, which is a mixture of the toner and the carrier is conveyed by magnetic force, and an electrostatic latent image is developed by electrostatic force. Has become.

However, in this two-component developing system, the size of the developing device becomes large and it is necessary to control the mixing ratio of the toner and the carrier, which complicates the control system.

Therefore, recently, in a small copying machine or a small printer, one-component development which does not require a carrier is becoming mainstream. Among them, the non-magnetic one-component development in which the magnet is not provided in the developing device is advantageous in reducing the size and weight of the developing device and reducing the cost.

In such a developing system, when the elastic roller is used as the developing roller, the electrostatic latent image holding member is damaged even when the electrostatic latent image holding member is brought into contact with the electrophotographic photosensitive member (electrophotographically, photoconductor). Never. As described above, by bringing the developing roller and the electrostatic latent image holding member into contact with each other, the developing electrode is brought closer to the electrostatic latent image, so that the sharpness of the character or line image is improved and high-quality development can be performed. ..

In such a developing method, the distance between the developing electrode and the electrostatic latent image is mainly determined by the particle size of the toner, and bringing the developing electrode close to the electrostatic latent image reduces the toner particle size. It will be.

[0007]

However, reducing the toner particle size increases the charging area, which increases the charge amount of the toner and, conversely, lowers the image density. Therefore, an object of the present invention is to provide a developer that does not increase the charge amount even if the particle size is reduced.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is a developer for developing particles held on a holding member and charged by a charging means, and then brought into contact with a portion to be developed for development. When the shape factor R of the developing particles is the diameter of a circle having the same area as the projected area of the particles / the diameter of a circle having the same perimeter as the projected perimeter of the particles, R ≧ 1.3
And a developer container that is provided to face the image carrier that carries the image and that contains the developer, and a developer supply that is provided in the developer container and supplies the developer to the image carrier. And a charging means for frictionally charging the developer supplied to the image carrier by the developer supplying means, and the shape factor R of the particles of the developer has the same area as the projected area of the particles. Diameter / the diameter of a circle having the same perimeter as the projected perimeter of the particles, the relationship of R ≧ 1.3 is satisfied, and further, the toner is triboelectrically charged by the charging means and supplied to the image carrier. In a method for producing a developer for developing an electrostatic latent image on a body, a mother polymerized particle and a child polymerized particle smaller than the mother polymerized particle are made by a polymerization method, and the child polymerized particle is attached around the mother polymerized particle, By fusing with heat,
When the shape factor R of the developing particles is the diameter of a circle having the same area as the projected area of the particles / the diameter of a circle having the same perimeter as the projected perimeter of the particles, development satisfying the relation of R ≧ 1.3 Manufacture the agent.

[0009]

By the above means, the chargeable surface area on the surface of the developer is reduced, and the opportunity and amount of the developer being charged are reduced. As a result, even if the particle size is small, the charge amount of the developer can be suppressed to a low value, and high-quality development can be performed while maintaining a high image density.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIG.

FIG. 1 shows a contact type one-component developing device provided in an electrophotographic apparatus, in which 1 is a developing container.
An opening 2 is formed on the front surface of the developing container 1, and the opening 2 faces an organic photosensitive drum 4 as a negatively charged image carrier that rotates in the arrow direction at a peripheral speed of 70 mm / sec.

At the inner bottom of the developing container 1, there is provided a developing roller 3 as a developer supplying means having conductivity and elasticity and rotating at a peripheral speed of 180 mm / sec in the direction of the arrow in the drawing. The roller 3 is in contact with the photosensitive drum 4 with a contact width (developing nip) of about 0.5 mm to 4 mm.

The metal shaft 3a of the developing roller 3 has 10
The developing bias applying means 15 is connected via a protective resistance of 0 k to 50 MΩ. Development bias is -220v
Therefore, the surface potential of the photoconductor is -550V.

The inside of the developing container 1 is divided into front and rear chambers 7 and 8 by a partition plate 6. The front chamber 7 is provided with a blade 9 as a developer regulating member as a charging means, and the rear chamber 8 contains a mixer 10 and a non-magnetic toner 11 as a developer. The blade 9 forms a one-component developing layer, and the developer is brought into contact with the photoreceptor 4 to perform development.

A toner supply roller 12 is provided on the inner bottom of the developing container 1, and the toner supply roller 12 is provided.
Is in contact with the developing roller 3 and rotates in a direction in which the contact portion rubs against the developing roller 3.

The toner supply roller 12 supplies the toner 11 to the developing roller 3 and also has a function of scraping off a part of the toner 11 remaining on the developing roller 3 without being developed. .. The blade 9 has a blade holder 13 and a blade holder 14,
It is held rotatably about a fulcrum 15. In the present invention, the toner 11 is negatively charged because the reversal development is performed using the negatively charged organic photosensitive drum 4.

However, at the time of development, the non-magnetic toner 11 in the developing container 1 is sent to the toner supply roller 12 while being agitated by the mixer 10, and the toner supply roller 1 is supplied.
2, the toner 11 is supplied to the developing roller 3.

The toner supplied by the toner supply roller 12 onto the developing roller 3 is frictionally charged with the developing roller 3, and the blade 9 is caused by electrostatic force and physical force.
Is transported to. The toner on the developing roller 3 is charged by frictional charging while the passing amount is regulated by the blade 9.

After passing through the blade 9, the toner 11 is
The toner 11 which is sufficiently charged and has a uniform layer is formed, and the toner 11 with the layer formed is brought into sliding contact with the photosensitive drum 4 by the rotation of the developing roller 3 to develop the toner. After this development, the toner remaining on the developing roller 3 passes through the recovery blade 21 and returns to the inside of the developing container 1. By the way, the toner 11 is manufactured by the manufacturing method described later, and the shape factor R of the particles is 1.41.

Here, R is the diameter of a circle having the same area as the projected area of toner particles (projected perimeter ellipse diameter) / toner.
It is the diameter of the circle having the same perimeter as the projected perimeter of the particle (projected area equivalent circle diameter).

The polymerizable monomer used in the production of Tona-11 is styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene. , 3,
4-dichlorostyrene, p-ethylstyrene, 2,4-
Dimethyl styrene, pn-butyl styrene, p-te
rt-butyl styrene, pn-hexyl styrene, p
-N-octyl styrene, pn-nonyl styrene, p
Styrene and its derivatives such as -n-decylstyrene and pn-dodecylstyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride, etc. Vinyl halides; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, methacryl. Α-Methylene aliphatic monocarboxylic acid esters such as dodecyl acid ester, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; Methyl acid, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc. Acrylic acid esters of vinyl methyl ether,
Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and the like There are vinyl monomers such as N-vinyl compounds; vinylnaphthalenes; acrylic acid such as acrylonitrile, methacrylonitrile and acrylamide, or methacrylic derivatives.

Examples of the polymerization initiator used for polymerizing the above monomers include benzoyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, potassium persulfate, ammonium persulfate, and peroxide. Acetyl oxide, tetramethylthiuram disulfide, azobisisobutyronitrile, azobiscyclohexanenitrile, phenylazotriphenylmethane, triethylaluminum, trimethylaluminum, ethylaluminum dichloride, diethylaluminium chloride, tetraethyllead, diethylzinc, diethylcadmium, Tetraethyl tin, titanium tetrachloride, aluminum chloride, aluminum bromide, stannic chloride, boron trifluoride diethyl etherate, boron trifluoride, chloride Lead, it is possible to perform the polymerization of the monomers using phosphorus pentafluoride and the like. Generally, about 0.5 to 5% by weight of monomer of initiator is sufficient.

Examples of the colorant include carbon black, fast yellow G, benzidine yellow, pigment yellow, indo first, orange, irgadine red, carmine FB, and permanent bordeaux F.
Known colorants such as RR, Pigment Orange R, Resole Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, and Quinacridone can be used. In addition, magnetic powder having colorability and CCA (charge control agent) can be used as the colorant. The magnetic powder referred to here is, for example, a ferromagnetic metal powder such as iron, cobalt or nickel, or an alloy or compound powder such as magnetite, hematite or ferrite.

As the charge control agent, nigrosine dye, quaternary ammonium salt, alkylamide, alkoxylated amine, phosphorus simple substance and its compound, tungsten simple substance and its compound, molybdic acid chelate pigment,
A metal complex salt of monoazo dye, chlorinated polyolefin, chlorinated polyester, metal salt of naphthenic acid, metal salt of fatty acid and the like can be used.

Further, in the present invention, a surfactant can be used in order to promote the dispersion of the monomer composition at the time of dispersion and polymerization, and examples of such a surfactant include sodium dodecylbenzenesulfonate and tetradecyl. Sodium sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium allyl-alkyl-polyethersulfonate, sodium oleate, sodium laurate, sodium caprate, sodium caprylate, sodium caproate, sodium stearate, calcium oleate, 3 , 3-disulfone diphenylurea-
4,4-diazobis-amino-8-naphthol-6-
Sodium sulfonate, orthocarboxybenzene-
Azodimethylaniline, 2,2,5,5-tetramethyl-triphenylmethane-4,4-diazobis-β-
Naphthol-sodium disulfonate and the like. Next, a method of manufacturing the toner 11 will be described.

First, 85 parts of styrene, 15 parts of ethylamino acrylate, and 3 parts of acrylic acid are mixed with 100 parts of water, 1 part of nonionic emulsifier (Emulgen 950),
Add an anionic emulsifier (Neogen R) (1.5 parts) and potassium persulfate (0.5 parts) to an aqueous mixture and stir at 70 ° C. for 8 hours.
Emulsion polymerization is carried out for a time to obtain a resin emulsion. Next, to 100 parts of this resin emulsion, 5 parts of carbon black (Legal 330R), 1 part of charge control agent (E82),
Is poured into water containing 0.1 part of sodium dodecylbenzenesulfonate, diethylamine is added to adjust pH to 5.5, and then dispersed with a nanomizer. Then, while stirring this, the temperature is raised to 90 ° C., 3 parts of hydrogen peroxide solution is added, and the mixture is polymerized for 6 hours to obtain polymer particles A. Next, except that the polymerization time after adding the hydrogen peroxide solution was set to 1 hour, the same procedure as the above-mentioned polymer particles was used to prepare polymer particle B.
To get

Then, the polymer particles A and the polymer particles B are mixed, gradually heated to 98 ° C. and stirred for 4 hours. After cooling and filtering, this is vacuum dried at 45 ° C. for 10 hours. To 100 parts of the particles thus obtained, silica (R97
2) is externally added and classified to finally obtain a toner having a volume average particle diameter of 6.5 μm.

When this toner shape was observed with a scanning electron microscope (manufactured by Akashi beam mterinology), it was found to be the shape of Compei sugar, and this shape was analyzed by an image analyzer Tospics (Toshiba Corporation). When the coefficient R was calculated, it was R = 1.41.

The toner particles were mixed with iron powder, and the charge amount was measured by a blow-off charge measuring device (manufactured by Toshiba Chemical Co., Ltd.). As a result, it was -10.8 μC / g, and the charge amount distribution was very sharp. was. When a printing test was conducted by this developing method, a stable image having a high image density of 1.4 and a high resolution was obtained. Comparative Example 1

85 parts styrene, 15 butyl acrylate
Parts, acrylic acid 3 parts, monomer mixture liquid 100 parts, water 100 parts, nonionic emulsifier (Emulgen 950) 1 part, anion emulsifier (Neogen R) 1.5 parts, potassium persulfate 0.5 parts, and added to an aqueous solution mixture and stirred Emulsion polymerization was carried out at 70 ° C. for 8 hours to obtain a resin emulsion. Next, for 100 parts of this resin emulsion, carbon black (Legal 330
R) 5 parts and charge control agent (E82) 1 part were put into water containing 0.1 part of sodium dodecylbenzenesulfonate, diethylamine was added to adjust pH to 5.5, and then dispersed with a nanomizer. It was While stirring, the temperature was raised to 90 ° C., 3 parts of hydrogen peroxide solution was added, and polymerization was performed for 6.5 hours to obtain polymer particles. After cooling and filtering, vacuum drying was performed at 45 ° C. for 10 hours. 100 for the particles thus obtained
Silica (R972) was externally added to some parts and classified to finally obtain a toner having a volume average particle size of 6.3 μm. When the shape factor R was calculated in the same manner as in Example 1, R
Was 1.05. In addition, the toner particles were mixed with iron powder, and a blow-off charge measuring device (Toshiba Chemical Co., Ltd.)
The amount of charge was measured by -60.5 μC /
When the image is printed by the developing method of Example 1 with an image density of 0.
A poor image of 98 was obtained. Comparative example 2

Copolymer of styrene and butyl acrylate (85/15) 85 parts, carbon black (Regal 3
30R) 5 parts, resin powder 10 containing charge control agent (E82)
Parts were melt-kneaded at 120 ° C., the mixture was cooled and solidified, coarsely pulverized by a hammer mill, and finely pulverized by a jet mill. Silica (R972) was externally added to 100 parts of the particles thus obtained and classified to finally obtain a toner having a volume average particle size of 6.5 μm.

When the shape factor R was calculated in the same manner as in Example 1, it was R = 1.25. Further, when the toner particles were mixed with iron powder and the charge amount was measured by a blow-off charge measuring device (manufactured by Toshiba Chemical Co., Ltd.), -41.
When the image was printed with the developing method of Example 1 at 3 μC / g, an image having an image density of 1.12 and slightly defective was obtained. The present invention is not limited to the above embodiment, and the developer may be manufactured by the following method.

That is, a monomer mixture of 85 parts of styrene, 15 parts of ethylamino acrylate and 3 parts of acrylic acid is added to 100 parts of water, 1 part of a nonionic emulsifier (Emulgen 950).
Parts, anionic emulsifier (Neogen R) 1.5 parts, and potassium persulfate 0.5 parts in an aqueous solution mixture, and stirred at 70 ° C.
Emulsion polymerization is carried out for 8 hours to obtain a resin emulsion. next,
To 100 parts of this resin emulsion, 5 parts of carbon black (Regal 330R) was added to water containing 0.1 part of sodium dodecylbenzenesulfonate, and diethylamine was added to adjust the pH to 5.5, and then the nanomizer was used. Disperse with. Then, while stirring this, 9
The temperature is raised to 0 ° C., 3 parts of hydrogen peroxide solution is added, and the mixture is polymerized for 6 hours to obtain polymer particles A.

Next, except that the charge control agent (E82) (1 part) was added together when the carbon black was added, and the polymerization time after adding the hydrogen peroxide solution was set to 1 hour, the above-mentioned polymer particles A were used. Polymer particles B are obtained in the same manner as in.

Then, the polymer particles A and the polymer particles B are mixed, gradually heated to 98 ° C. and stirred for 4 hours. After cooling and filtering, this is vacuum dried at 45 ° C. for 10 hours. To 100 parts of the particles thus obtained, silica (R97
2) is externally added and classified to finally obtain a toner having a volume average particle diameter of 6.5 μm.

When this toner shape was observed with a scanning electron microscope (manufactured by Akashi beam mterinology), it had the shape of Compei sugar, and this shape was analyzed by an image analyzer Tospics (Toshiba Corporation). When the coefficient R was calculated, it was R = 1.41. The toner produced by this method contains the electrostatic control agent only in the protrusions, that is, the child polymerized particles, and the mother polymerized particles do not participate in the direct contact charging. According to this embodiment, since the charge control agent is contained only in the protrusions of the toner which are directly contact-charged, the charge can be stabilized. Since the mother polymer particles that are not involved in charging do not contain the charge control agent, the amount of the charge control agent used can be reduced.

[0037]

As described above, according to the present invention, the shape factor R of developing particles is the diameter of a circle having the same area as the projected area of the particles / the diameter of a circle having the same perimeter as the projected perimeter of the particles. At this time, since the relationship of R ≧ 1.3 is satisfied, the charge amount of each developer can be suppressed to a low value even if the particle size is small, and high-quality development can be performed while maintaining a high image density. It has the effect of being able to do it.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram illustrating a developing device that is an embodiment of the present invention.

[Explanation of symbols]

4 ... Photosensitive drum (image bearing member), 3 ... Developing roller (developer holding member), 9 ... Blade, (charging means), 11 ... Toner (developer).

Claims (4)

[Claims] 1. A developer, in which developing particles are held on a holding member and charged by a charging means, and then contacted with a developing portion to develop, the shape factor R of the developing particles is the same as the projected area of the particles. A developer characterized in that when the diameter of a circle having an area / the diameter of a circle having the same perimeter as the projected perimeter of a particle, the relationship of R ≧ 1.3 is satisfied. 2. The developer according to claim 1, wherein the developing particles have protrusions, and the protrusions contain a charge control agent. 3. A developing container, which is provided so as to face an image bearing member that carries an image and contains a developer, and a developer supplying unit that is provided in the developing container and supplies the developer to the image bearing member. Charging means for frictionally charging the developer supplied to the image carrier by the developer supplying means, wherein the shape factor R of the particles of the developer has the same area as the projected area of the particles. A developing device, wherein the relationship of R ≧ 1.3 is satisfied when the diameter is the diameter of a circle having the same circumference as the projected circumference of particles. 4. A method for producing a developer in which developing particles are triboelectrically charged by a charging means and supplied to an image carrier to develop an electrostatic latent image on the image carrier, wherein mother polymerization particles and mother polymerization are performed by a polymerization method. A circle having a shape factor R of the developing particles having the same area as the projected area of the particles by making child polymerization particles smaller than the particles, attaching the child polymerization particles around the mother polymerization particles, and fusing with heat. And the diameter of a circle having the same perimeter as the projected perimeter of the particles, the method for producing the developer is characterized in that the developer satisfying the relation of R ≧ 1.3 is produced.