JP3145562B2 - Electrophotographic toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electrostatic recording,
It relates to electrophotographic toner that is used by a developer for developing an in electrostatic charge image on the electrostatic printing and the like. More particularly a copying machine using a direct or indirect electrophotographic developing system, laser printers and relates to Ru electronic photographic toner over is used in plain paper facsimile.

[0002]

2. Description of the Related Art A developer used in electrophotography, electrostatic recording, electrostatic printing, and the like is, for example, once applied to an image carrier such as a photosensitive member on which an electrostatic image is formed in a developing process. After being adhered and then transferred from the photoreceptor to transfer paper in a transfer step, it is fixed on the paper surface in a fixing step. At this time, as a developer for developing an electrostatic image formed on the latent image holding surface, a two-component developer composed of a carrier and a toner and a one-component developer (a magnetic toner, Non-magnetic toner) is known.

[0003] As the toner contained in the developer, there are a positively charged toner and a negatively charged toner. Conventionally, as an additive to a toner for imparting a positively chargeable property, a nigrosine dye, a quaternary ammonium salt or the like has been used. There are known charge control agents, coating agents for imparting predetermined chargeability to carriers, and the like. On the other hand, as a substance imparting negative chargeability, a charge control agent such as a metal-containing azo dye, an inorganic powder, an organic powder, and a carrier coating agent are known.

A method has been proposed in which toner particles are mixed with an inorganic powder such as various metal oxides for the purpose of improving the flow characteristics and charging characteristics of the toner. A method of treating with a specific silane coupling agent, a titanate coupling agent, a silicone oil, an organic acid, or the like for the purpose of modifying the surface hydrophobicity, charging characteristics, and the like, a method of coating a specific resin, and the like have also been proposed. .
Examples of the inorganic powder include silicon dioxide (silica), titanium dioxide (titania), aluminum oxide,
Zinc oxide, magnesium oxide, cerium oxide, iron oxide,
Copper oxide, tin oxide and the like are known.

As for a toner fluidizing agent, use of silica fine particles subjected to a hydrophobizing treatment is disclosed in JP-A-48-57.
No. 82, JP-A-48-47345, JP-A-55-12
No. 0041, JP-A-59-34539 and the like. Specifically, for example, silica fine particles obtained by reacting silica fine particles with an organic silicon compound such as dimethyldichlorosilane, hexamethyldisilazane, or silicone oil and replacing the silanol groups on the surface of the silica fine particles with an organic group to make them hydrophobic are used. ing.

[0006] Of these, exhibit sufficient hydrophobicity,
As the hydrophobizing agent which exhibits excellent transferability when contained in a toner, silicone oil is preferable, but since silicone oil is a high molecular substance, silica fine particles are easily aggregated during the hydrophobizing treatment, Some of them had a disadvantage that they remained as aggregates of several tens of μm even after being dispersed in the toner, and were developed in the image area to form white spots and deteriorate image quality.

[0007] The addition amount of silicone oil is known from JP-A-61-277964 and the like, but the addition amount of silicone oil is A / 10 ± A / 20 parts by weight per 100 parts by weight of silica. (A: specific surface area of silica fine powder). According to the description method of the present invention, the amount of the silicone oil added is equal to 0.5 to 1.5 mg / m ² per silica based surface area.
However, in this case, fogging and the like have been improved with ordinary transfer paper such as PPC paper which is commercially available. However, when a thick paper such as a postcard or an OHP sheet is used as the transfer paper, the “character The problem of "missing" is not solved, and
Dramatic improvement could not be achieved in the characteristics relating to the aging stability.

[0008]

The object of the present invention is to solve the above is to solve the above problems, it is to provide a developing property, transferring property and electrophotographic toner over which is excellent in stability over time.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, an inorganic fine particle having a specific particle size, which has been surface-treated with silicone oil, is used as a fluidizing agent for electrophotographic toner. When used for electrophotographic toner,
It is possible to provide a developer with excellent developability, transferability and stability over time, and by using the developer, it is possible to obtain high quality without background with proper image density without deteriorating each part of the developing machine. It was found that a stable copy image could be provided stably. In addition, the problem with the use of silicone oil (the silica fine particles tend to agglomerate during the hydrophobizing treatment, and remain in the form of aggregates of several tens of μm even after being dispersed in the toner. The disadvantage is that the particle size of the inorganic fine particles is made larger than the generally used range (several nm to 20 nm), and the range is 100 nm or less, which is the range usable as a fluidizing agent for electrophotographic toner. To reduce the amount of aggregates,
The present inventors have found that the amount of silicone oil added can be increased with respect to the unit surface area of the inorganic fine particles, and have reached the present invention.

Further investigations have been made to solve the above-mentioned problems as the toner for electrophotography. As a result, the addition amount of the inorganic fine particles was achieved by covering the toner by 30% or more. Further, as a binder resin of the toner, the following general formula (I)

[0011]

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(Wherein, R ¹ represents an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the sum of the average values thereof is 2 to 16). And the following general formula (II) or (III)

[0013]

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(Wherein R ² and R ³ are the same or different and each represent an alkyl group or an alkenyl group having 4 to 20 carbon atoms). By using a polyester resin obtained by condensation polymerization of an acid component containing 10 to 30 mol% of trimellitic acid or its anhydride, a resin having a high toughness that cannot be obtained with other binder resins. Thus, the inorganic fine particles were hardly embedded in the toner for a long period of time, and the problem of the stability over time was easily achieved.

[0015] That is, the gist of the present invention, an electrostatic image bearing member
The toner image is developed by developing the electrostatic image of
-Image is formed and transferred to the surface of the electrostatic image carrier via a transfer material
Means for bringing the toner image into electrostatic contact with the transfer material by bringing
At least the binder resin and coloring used in the photo recording device
A toner for electrophotography, comprising:
Is externally added with a fluidizing agent, and the binder resin is generally
A diol component represented by the formula (I);
Is a divalent carboxylic acid represented by (III) or its anhydride
1-50 mol% of trimellitic acid or its
With an acid component containing 10 to 30 mol% of an anhydride of
A polyester resin obtained at least,
Average particle size of primary particles treated with silicone oil
Inorganic fine particles having a diameter of 30 nm or more and 100 nm or less.
The amount of the silicone oil added to the surface of the inorganic fine particles
The present invention relates to an electrophotographic toner having a weight per product of ² to 3 mg / m2 .

The fluidizing agent for an electrophotographic toner according to the present invention has an average primary particle size of 3 which is treated with silicone oil.
0 to 100 nm or less inorganic fine particles, wherein the amount of the silicone oil added is 2 per surface area of the inorganic fine particles.
３3 mg / m ² .

As the silicone oil used in the treatment,
Dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, alkyl-modified silicone oil, fluorine-modified silicone oil having a viscosity at 25 ° C. of 50 to 10,000 cS,
Polyether-modified silicone oil, alcohol-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, epoxy / polyether-modified silicone oil, phenol-modified silicone oil,
Carboxyl-modified silicone oil, mercapto-modified silicone oil and the like can be used.

The average particle size of the primary particles of the inorganic fine particles treated with the silicone oil is usually 30 nm to 100 nm.
Or less, preferably 30 nm or more and 70 nm or less. If it is smaller than this range, the inorganic fine particles tend to be buried in the toner during use of the toner, and the effect is hardly maintained. If the ratio is larger than this range, adverse effects such as the inorganic fine particles easily damaging the photoreceptor surface tend to be increased. Here, the average particle diameter is a number average particle diameter.

The particle size of the inorganic fine particles used in the present invention can be measured by a particle size distribution measuring apparatus utilizing dynamic light scattering. Since it is difficult to dissociate the secondary aggregation of particles, scanning is performed. It is best to determine the particle size from a photograph obtained by a scanning electron microscope or a transmission electron microscope. Another index is that the inorganic fine particles have a true specific gravity of 2.3 g /
For silica cm ^2, BET specific surface area 20 to 80 m ²
/ G corresponds to the above particle diameter.

As the inorganic fine particles of the present invention, conventionally known materials can be used. Specific examples include silicon dioxide (silica), titanium dioxide (titania), aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, and tin oxide. Preferred examples of the present invention include MOX80 (average particle diameter, about 30 nm), OX50 manufactured by Nippon Aerosil Co., Ltd.
(Average particle diameter, about 40 nm) and TT600 (average particle diameter, about 40 nm), manufactured by Idemitsu Kosan Co., Ltd., IT-PB (average particle diameter, about 40 nm) and IT-PC (average particle diameter, about 6 nm)
0 nm), TAF110A (average particle diameter, about 40 to 50 nm) and TAF510 (average particle diameter, about 40 to 50 nm) manufactured by Fuji Titanium Industry Co., Ltd. can be conveniently used. When used as an electrophotographic toner, these inorganic fine particles may be used alone or in combination of two or more.

The fluidizing agent for an electrophotographic toner according to the present invention is processed so that the addition amount of the silicone oil is usually ² to 3 mg / m ² per surface area of the inorganic fine particles. If the amount is less than this range, the effect of “missing characters” tends to be small. If the amount is more than this range, the cohesiveness of the inorganic fine particles tends to be strong, and it will not be possible to uniformly adhere to the toner surface. In the case of inorganic fine particles having a BET specific surface area of 50 m ³ / g, such an added amount corresponds to 10 to 15 parts by weight per 100 parts by weight of the inorganic fine particles.

Here, the surface area of the inorganic fine particles indicates the BET specific surface area, and can be measured by using a commercially available BET specific surface area measuring device by nitrogen adsorption, for example, manufactured by Shimadzu Corporation. A flow-type specific surface area automatic measurement device (flow soap 2300 type) or the like can be used. In the present invention, together with the fluidizing agent of the present invention, known inorganic fine particles not subjected to surface treatment and / or
One or more types of known inorganic fine particles surface-treated with a hydrophobizing agent other than silicone oil may be used in combination.

The electrophotographic toner of the present invention is an electrophotographic toner having an average particle diameter of at least 20 μm (usually 3 to 20 μm) comprising at least a binder resin and a colorant, wherein the fluidizing agent described above is applied to the toner surface. It is characterized by being externally added.

The composition of the toner used in the present invention comprises at least a binder resin and a colorant, and conventionally known ones can be used.

Examples of the binder resin for toner used in the present invention include styrenes such as styrene, chlorostyrene and α-methylstyrene: monoolefins such as ethylene, propylene, butylene and isobutylene: vinyl acetate and vinyl propionate. , Vinyl benzoate, vinyl butyrate and other vinyl esters: methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, dodecyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, methacryl Esters of α-methylene aliphatic monocarboxylic acids such as dodecyl acid: vinyl methyl ether, vinyl ethyl ether,
Vinyl ethers such as vinyl butyl ether: homopolymers and copolymers of vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone.

Further, natural and synthetic waxes, polyesters, polyamides, epoxy resins, polycarbonates, polyurethanes, silicone resins, fluorine resins,
A petroleum resin or the like can be used, but a polyester resin is preferably used.

As the polyester resin, the following general formula (I)

[0028]

Embedded image

(Wherein R ¹ represents an alkylene group having 2 to 4 carbon atoms, x and y are positive integers, and the sum of their average values is 2 to 16). And the following general formula (II) or (III)

[0030]

Embedded image

(Wherein R ² and R ³ are the same or different and each represent an alkyl group or an alkenyl group having 4 to 20 carbon atoms). A polyester resin obtained by condensation polymerization of an acid component containing 10 to 30 mol% of trimellitic acid or anhydride thereof is more preferable.

As the diol component of the general formula (I), for example, polyoxypropylene (2.2) -2,2-
Bis (4-hydroxyphenyl) propane, polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-
Bisphenol A-based monomers such as bis (4-hydroxyphenyl) propane and polyoxypropylene (16) -2,2-bis (4-hydroxyphenyl) propane are exemplified.

Other diol components include, for example, ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane,
Examples include hydrogenated bisphenol A, sorbitol, or their etherified polyhydroxyl compounds, ie, polyoxyethylene (10) sorbitol, polyoxyethylene (3) glycerin, polyoxyethylene (4) pentaerythritol, and the like.

[0034] The above general formula (II) or general formula (III), R ^2, R ³ are the same or different and is an alkyl or alkenyl group having 4 to 20 carbon atoms, R ^2, R Examples of ³ include an n-butyl group, an n-octyl group, an isooctyl group, an isododecyl group, an n-dodecenyl group, and the like. General formula (II) or general formula
Specific examples of the divalent carboxylic acid represented by (III) or an anhydride thereof include, for example, n-dodecenylsuccinic acid, isododecylsuccinic acid, isooctylsuccinic acid, n-octylsuccinic acid, n-butylsuccinic acid and the like. Succinic acid derivatives or anhydrides thereof;

Other acid components include, for example, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, trimellitic acid, pyromellitic acid and the like, and acid anhydrides and lower alkyl esters thereof. Examples include compounds used in the production of ordinary polyester resins.

The polyester resin used in the present invention is:
Usually, it can be produced by polycondensing a polyol component and a polycarboxylic acid component at a temperature of 180 ° C. to 250 ° C. in an inert gas atmosphere. At this time, in order to accelerate the reaction, a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate and the like can be used.

The coloring agent used in the toner includes carbon black: C.I. I. Pigment Yellow 1, 3, 74, 97, 98 etc. acetoacetate arylamide monoazo yellow pigments: C.I. I. Pigment
Acetoacetic acid arylamide-based disazo yellow pigments such as yellow 12, 13, 13, and 17; I. Solvent Yellow 19, 77, 79, C.I. I. Yellow dyes such as Disperse Yellow 164: C.I. I. Red or red pigments such as CI Pigment Red 48, 49: 1, 53: 1, 57, 57: 1, 81, 122 and 5; I. Red dyes such as Solvent Red 49, 52, 58 and 8: C.I. I. Pigment Blue 15: 3, etc., and blue colourants of copper phthalocyanine and its derivatives: C.I. I. Green pigments such as CI Pigment Green and 36 (Phthalocyanine Green) can be used. These dyes and pigments may be used alone or in combination of two or more.

The toner for electrophotography of the present invention may contain a charge control agent. As the charge control agent usable, for negatively charged toner, chromium azo complex dye, iron azo complex dye, cobalt Azo complex dyes, chromium-zinc-aluminum-boron complexes or salt compounds of salicylic acid or its derivatives, chromium-zinc-aluminum-boron complexes or salt compounds of naphtholic acid or its derivatives, chromium-zinc of benzylic acid or its derivatives
A surfactant such as zinc / aluminum / boron complex or salt compound, long-chain alkyl / carboxylate, long-chain alkyl / sulfonate, etc. is used for positively charged toner for nigrosine dye and its derivative, triphenylmethane derivative And derivatives such as quaternary ammonium salts, quaternary phosphonium salts, quaternary pyridinium salts, guanidine salts, amidine salts and the like.

In the toner, a magnetic substance such as ferrite, a conductivity adjuster, a metal oxide such as tin oxide, silica, alumina, zirconia, titania and zinc oxide, an extender pigment,
A reinforcing filler such as a fibrous substance, an antioxidant, a release agent, and the like may be added as necessary.

As a method for producing the toner of the present invention, conventionally known production methods such as a kneading and pulverizing method, a spray drying method, and a polymerization method can be used. For example, as a general example, first, a resin, a colorant, a wax, a charge control agent, and the like are uniformly dispersed and mixed in a known mixer, and then the mixture is mixed in a closed kneader or a single- or twin-screw extruder. Melt kneading,
After cooling, it may be pulverized and classified. In recent years, single-screw or twin-screw extruders have become the mainstream because of their advantages such as continuous production. For example, KTK twin-screw extruders manufactured by Kobe Steel, TEM extruders manufactured by Toshiba Machine Co., Ltd. A twin screw extruder manufactured by CK Corporation, a PCM type twin screw extruder manufactured by Ikegai Iron Works, or a kneader manufactured by Bus is preferably used.

The average particle diameter of the toner thus obtained is usually 20 μm or less, and the average particle diameter is 3 to 2 μm.
0 μm is preferred. Here, the average particle diameter is a volume average particle diameter.

In the electrophotographic toner of the present invention, the above-mentioned fluidizing agent is externally added to the surface of the toner. Such an external addition method may be performed by stirring and mixing the classified toner and the externally added inorganic fine particles with a high-speed stirrer such as a super mixer or a Henschel mixer. If necessary, the start developer toner and the replenishment toner may be mixed. The type and amount of the externally added inorganic fine particles to be used may be different. The mixing conditions such as the number of rotations and the mixing time for stirring may be determined as appropriate in accordance with the toner performance. It is more preferable that the inorganic fine particles be subjected to a crushing treatment in advance.

At this time, the coverage of the fluidizing agent for the electrophotographic toner is usually 30% or more, preferably 30 to 60%. If it is smaller than this range, the image tends to be conspicuous with “missing characters”. However, when silica is added to the toner as a fluidizing agent in the present invention, the silica actually adheres to the toner surface in a partially aggregated state, so that the actual coverage is low.

Accordingly, the coverage f in the present invention is calculated by the following general formula. f (%) = {3 / 2π × (D · ρτ) / (d · ρs) ×
C × 100 (where, the particle size of the fluidizing agent is d, and the particle size of the toner is D,
ρt and ρs are the true specific gravities of the toner and the fluidizing agent, respectively. C is the weight ratio of fluidizer / toner. )

When the toner of the present invention is used in a two-component developer, the toner may be mixed with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is based on 100 parts by weight of the carrier. The amount of the toner is preferably 1 to 10 parts by weight. As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, and magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. In addition, those whose surfaces are coated with a known silicone resin, acrylic resin, fluorine resin, styrene resin, or the like, or a mixture of these resins can also be suitably used.

The toner of the present invention can be used as a one-component magnetic toner or a non-magnetic toner without using a carrier.

The transferability of the toner of the present invention can be improved by using a conventionally known electrophotographic developing device equipped with a corotron transfer device. However, the transfer means is provided on the surface of the electrostatic image carrier through a transfer material. When used in an electrophotographic developing device for electrostatically transferring a toner image to a transfer material by contacting the same, the effect is particularly effective.

Hereinafter, an electrophotographic recording apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway view of a main configuration of an electrophotographic recording apparatus according to the present invention.
The electrophotographic recording apparatus includes a photoconductor 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6.

The photosensitive member 1 is formed of a conductor such as aluminum, for example, and has a photosensitive layer formed by coating a photosensitive conductive material on the outer peripheral surface. The photoconductor 1 is rotated in a direction indicated by an arrow by a drive transmission mechanism (not shown). Around the photosensitive member 1, a charging device 2, an exposing device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the photosensitive member 1.

The charging device 2 is composed of, for example, a well-known scorotron charger, and uniformly charges the surface of the photoreceptor 1 to a predetermined potential (for example, -600 V). The exposure device 3 includes an LED head and forms an electrostatic latent image on the photosensitive surface of the photosensitive member 1 by exposing the photosensitive surface of the photosensitive member 1. The developing device 4 includes a toner hopper 41, a toner pack 42, a supply roller 43, a developing roller 44, a developing blade 4
5, a support rod 46, a leaf spring 47, a support 48, and an agitator 49.

The toner hopper 41 has a part of a side surface and
It is a hollow container having an open upper surface, and stores the toner of the present invention in an internal space. A toner pack 42 is mounted in the upper opening 41a of the toner hopper 41. The toner pack 42 is a container having an opening on one side, the inside of which is filled with toner, and the opening is sealed by a seal sheet. And the toner pack 42
As shown, the toner is supplied to the toner hopper 41.

The supply roller 43 is made of a conductive sponge, and is disposed at an opening on the side surface of the toner hopper 41 with a part thereof positioned inside the toner hopper 41. The supply roller 43 is in contact with the developing roller 44. The developing roller 44 is disposed between the photoconductor 1 and the supply roller 43. Developing roller 44
Are in contact with the photoconductor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are respectively rotated in a direction indicated by an arrow by a rotation driving mechanism (not shown). The supply roller 43 carries the toner stored in the toner hopper 41 and supplies the toner to the developing roller 44. The developing roller 44 carries the toner supplied by the supply roller 43 and contacts the surface of the photoconductor 1.

The developing blade 45 is formed of a silicone resin, a urethane resin or the like. The developing blade 45 is supported by a cylindrical support bar 46 arranged in parallel with the developing roller 44, and is in contact with the developing roller 44. The support rod 46 is pressed by a predetermined force (50 g) toward the developing roller 44 by a leaf spring 47 fixed to the support 48.
/ Cm to 150 g / cm). For this reason, the developing blade 45 presses the developing roller 44 with a predetermined force.
Is pressed. The support 48 is a toner hopper 41
Is fixed to the side wall.

The agitator 49 is rotated in a direction indicated by an arrow by a rotation drive mechanism (not shown).
The toner is supplied to the supply roller 43 while stirring the toner.
To the side.

The transfer device 5 has a transfer roller 51 arranged in parallel with the photosensitive member 1. To the transfer roller 51, a transfer voltage having a predetermined voltage value (for example, +1350 V) having a polarity opposite to the charged potential of the toner is applied from a transfer power supply (not shown). The transfer device 5 includes the photosensitive member 1
The toner image formed on the photoconductor 1 is transferred to the transfer paper P inserted between the transfer roller 51 and the transfer roller 51.

On the other hand, the cleaning device 6 comprises a cleaning blade 61, a waste toner container 62, a waste toner roller 63, and a check valve 64. The cleaning blade 61 is disposed in contact with the photoconductor 1, and scrapes off toner adhered to the photoconductor 1. Waste toner container 62
Collects the toner scraped off by the cleaning blade 61. The waste toner roller 63 conveys the toner scraped off by the cleaning blade 61 to the waste toner container 62 side. The backflow prevention valve 64 prevents the toner in the waste toner container 62 from flowing back to the photoconductor 1 side.

In the electrophotographic developing apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoconductor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. continue,
The charged photosensitive surface of the photoreceptor 1 is exposed by the exposure device 3 in accordance with an image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. Then, the developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photosensitive member 1.

The developing device 4 carries the toner mainly supplied by the supply roller 43 from the toner hopper on the developing roller 44, transports the toner, and contacts the surface of the photoconductor 1. When the toner carried on the developing roller 44 is transported, the toner is thinned by the developing blade 45,
It is frictionally charged to a predetermined polarity (here, the same polarity as the charging potential of the photoconductor 1 and a negative polarity).

A developing bias having the same polarity as the charging potential of the photosensitive member 1 and a low potential (for example, -200 V) is applied to the developing roller 44 from a developing bias power supply (not shown). The toner is selectively adhered to the photoreceptor 1 by the action of an electric field between the charges of the toner. That is, the toner is applied to the unexposed portion on the photoreceptor 1 because the photoreceptor 1 has a high potential. Toner is not adhered, and toner adheres to the exposed and neutralized portion because the photoconductor 1 side has a low potential. Thus, a toner image corresponding to the electrostatic latent image is formed on the surface of the photoconductor 1. Then, the toner image is transferred to the transfer paper P by the transfer device 5.

When recording an image, the transfer device 5
A positive transfer voltage (for example, +13
50V) is applied. Photoconductor 1 and transfer roller 5
The transfer paper P is inserted between the transfer paper 1 and the transfer roller 51. Here, since the electric charge injected into the back surface of the transfer paper P is positive, the negatively charged toner is attracted to the transfer paper P side, whereby the toner image formed on the surface of the photoconductor 1 is removed. The image is transferred to the transfer paper P. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6 after the transfer paper P is peeled off.

[0061]

EXAMPLES Examples of the present invention will be described below, but the present invention is of course not limited to these examples. In the examples, what is indicated as "parts" indicates parts by weight unless otherwise specified.

Example of Resin Production (Polyester Resin) Polyoxypropylene (2.2) -2,2-bis (4-
(Hydroxyphenyl) propane 700 g, fumaric acid 13
0 g, n-dodecenyl succinic anhydride 53.4 g, and hydroquinone 0.1 g were placed in a glass 1-liter four-necked flask, fitted with a thermometer, a stainless steel stirring rod, a falling condenser, and a nitrogen inlet tube. 23
The temperature was raised to 0 ° C., and the reaction was carried out while stirring under a nitrogen stream. When the water generated by the reaction stops flowing out, the acid value is measured (according to JIS K0070) to 1.5K.
OH mg / g. Further, trimellitic anhydride 63.
4 g was added and reacted for about 8 hours, and the acid value was 20 KOHmg /
When the reaction reached g, the reaction was terminated. The obtained resin was a pale yellow solid and had a softening temperature of 120 ° C. by a ring and ball method.

Examples 1 to 4 and Comparative Examples 1 to 5 100 parts of polyester resin obtained above 3 parts of carbon black 1.5 parts of chromium / azo complex 1 part of low molecular weight polypropylene / wax 1 part

The above composition was pre-mixed, kneaded in a biaxial kneader heated to 120 ° C., cooled, and the cooled product was coarsely pulverized by a mechanical pulverizer until it passed a 2 mm mesh, followed by wind pulverization and classification. Pulverized and classified by a machine, and the average particle size is 10.5 μm as a weight median particle size of a Coulter counter.
A toner matrix was prepared such that

The inorganic fine particles (fluidizer) to be externally added to the toner surface are obtained by treating the inorganic fine particles listed in Table 1 with silicone oil or the like. The surface treatment of the toner with the fluidizing agent of the present invention is carried out by applying the fluidizing agent to 100 parts of the toner base so that the coverage is 30% or more.
The mixture was mixed with a Henschel mixer. Thus, a toner to be used for image evaluation was prepared.

[0066]

[Table 1]

The surface treatment of the inorganic fine particles in the present invention was performed as follows. (1) 100 parts of the inorganic fine particle precursor is stirred in a mixing tank. (2) A required amount of the treatment agent is diluted with a solvent and sprayed on the inorganic fine particles in the mixing tank. (3) The temperature in the vessel is raised to 105 ° C. while maintaining the stirring, and maintained for 2 hours. (4) Remove after cooling.

Using the developer obtained as described above, it is generally considered that the development of “missing characters” is likely to occur. The toner-fixed image was evaluated as follows using an electrophotographic recording apparatus that brought the toner image into electrostatic contact with the transfer material in contact. Table 2 shows the results. In addition, as shown in FIG. 2, “missing” refers to a state where the toner is not transferred to a portion where the toner is to be originally transferred within a line constituting a character or the like, and the transfer material remains as it is. It means that it has become.

[0069]

[Table 2]

(A) Transfer state: A very severe OHP sheet was passed through under the transfer conditions and the like, and the state of “missing characters” was confirmed. ：: good, Δ: practicable, ×: not practicable (b) Image quality: Photoreceptor fog, toner scattering, roughness, etc. were visually evaluated. ：: good, Δ: practical, ×: not practical (c) Image white spots: White spots due to silica lumps in the image area were visually evaluated. ：: good, Δ: practical, ×: impractical These evaluations were made at the time of initial printing and after printing of 12,000 sheets.

From the results of these evaluations, it was found that the average primary particle diameter of the particles treated with silicone oil was 30 nm or more and 1% or more.
Inorganic fine particles having a particle size of not more than 00 nm, wherein the amount of silicone oil added is 2 to 3 mg / m 2 per surface area of the inorganic fine particles.
^The fluidizing agent for an electrophotographic toner, which is characterized in that it is ² , is extremely effective. In an electrophotographic toner having an average particle diameter of 20 μm or less, the inorganic fine particles are externally added to stabilize with time to obtain a transfer state. The image quality was excellent, and an image without white spots could be provided.

Example 5 Styrene / n-butyl methacrylate copolymer resin 100 parts (weight average molecular weight = 75,000, number average molecular weight = 20,000, glass transition point = 65 ° C.) Carbon black 3 parts Chromium azo complex 1 .5 parts Low molecular weight polypropylene wax 1 part

The above composition was premixed, kneaded in a twin-screw rudder heated to 120 ° C., cooled, and the cooled product was coarsely pulverized by a mechanical pulverizer until it passed a 2 mm mesh, followed by wind pulverization and classification. Pulverized and classified by a machine, and the average particle size is 10.5 μm as a weight median particle size of a Coulter counter.
A toner matrix was prepared such that

The inorganic fine particles (fluidizing agent) externally added to the toner surface are obtained by treating the inorganic fine particles listed in Table 1 with silicone oil or the like. The surface treatment of the toner with the fluidizing agent of the present invention is carried out by applying the fluidizing agent to 100 parts of the toner base so that the coverage is 30% or more.
The mixture was mixed with a Henschel mixer. Thus, a toner to be used for image evaluation was prepared.

Comparative Example 6 The toner was subjected to a surface treatment with the inorganic fine particles of Comparative Example 4. To 100 parts of the toner base, 1.0 part of each was added so that the coverage became 30% or more, and mixed with a Henschel mixer to prepare a toner. The same evaluation as above was performed on the obtained toner. It is described in Table 3.

[0076]

[Table 3]

Even if styrene / acryl is used as the binder resin, there is no practical problem if the inorganic fine particles of the present invention are used. However, as the binder resin, a diol component represented by the general formula (I):
An acid component containing 1 to 50 mol% of a divalent carboxylic acid or its anhydride represented by the general formula (II) or (III) and 10 to 30 mol% of trimellitic acid or its anhydride is used. By using the polyester resin obtained by polymerization, it was possible to provide an image with more excellent stability over time.

[0078]

By using the fluidizing agent and the toner for electrophotography of the present invention, a developer excellent in developability, transferability and stability with time can be provided. It is possible to provide an electrophotographic developing apparatus capable of stably obtaining a high-quality copy image without a background at an appropriate image density without deteriorating each part of the machine over a long period of time.

More specifically, the following effects can be obtained. (1) For electrophotography that provides high-quality images that have no background even when thick transfer paper such as postcards or OHP films are used, and are free from phenomena such as “missing characters” or are suppressed. A toner and an electrophotographic developing device can be provided. (2) suppressing fog on an electrostatic image carrier such as a photoconductor,
It is possible to provide an electrophotographic toner and an electrophotographic developing device having excellent stability over time and durability. (3) In an electrophotographic recording apparatus in which a phenomenon such as “missing of characters” is likely to occur, a transfer unit is brought into contact with a surface of an electrostatic image carrier via a transfer material, and a toner image is electrostatically transferred to the transfer material. It is possible to provide an electrophotographic developing device capable of suppressing phenomena such as “missing characters” over a long period of time.

[Brief description of the drawings]

FIG. 1 is a partially cutaway view of a main configuration of an electrophotographic recording apparatus according to the present invention.

FIG. 2 is a diagram illustrating “missing characters”;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Cleaning device P Transfer paper T Toner

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masayuki Maruta 4-34-22 Mai, Hannan-shi, Osaka (72) Inventor Yasuhiro Hidaka 889-3, Ononaka, Kainan-shi, Wakayama, Japan (72) Inventor Hiroshi Hashizume Tokyo 3-1, 1-1 Asahigaoka, Hino-shi, Tokyo Toshiba Hino Factory Co., Ltd. (72) Inventor Tetsuya Nakamura 3-1-1, Asahigaoka, Hino-shi, Tokyo 1 Toshiba Hino Factory Co., Ltd. (72) Hirotaka Fukuyama Tokyo 3-1, 1-1 Asahigaoka, Hino-shi, Toshiba Hino Factory Co., Ltd. (56) References JP-A-4-337738 (JP, A) JP-A-6-51554 (JP, A) JP-A-62-174772 ( JP, A) JP-A-61-114248 (JP, A) JP-A-3-121462 (JP, A) JP-A-4-70671 (JP, A) JP-A-61-176946 (JP, A) Hei 4-152354 (JP, A) 4-152356 (JP, A) JP Akira 62-215964 (JP, A) JP Akira 60-112052 (JP, A)

Claims (2)

(57) [Claims] An electrostatic charge image formed on an electrostatic image carrier;
Develop with a developing toner to form a toner image,
The transfer means is brought into contact with the surface of the image carrier via a transfer material so that the toner
-Used in an electrophotographic recording device that electrostatically transfers an image to the transfer material
Electrophotography composed of at least a binder resin and a colorant
Toner, the surface of which is externally added with a fluidizing agent.
Wherein the binder resin is represented by the following general formula (I) : (Wherein, R ¹ represents an alkylene group having 2 to 4 carbon atoms;
x and y are positive integers, and the sum of the average values is 2 to 16
It is. ) And a diol component represented by the following general formula:
(II) or (III) (Wherein R ² and R ³ are the same or different,
Represents an alkyl group or an alkenyl group represented by Formulas 4 to 20
You. ) Represents a divalent carboxylic acid or an anhydride thereof
1 to 50 mol%, and trimellitic acid or its absence
Polycondensation with an acid component containing 10 to 30 mol% of water
Polyester resin obtained by mixing
The average particle size of primary particles treated with silicone oil is
Inorganic fine particles of 30 nm or more and 100 nm or less,
The amount of silicone oil added corresponds to the surface area of the inorganic fine particles.
An electrophotographic toner having a weight of ² to 3 mg / m ² . 2. A flow electrophotographic toner of claim 1, wherein the coverage and wherein the at least 30% by whether agents.