JPS5810749A - Electrostatic charge image developer - Google Patents

Abstract

PURPOSE:To obtain an electrostatic charge image developer which does not generate any offset phenomena in the stage of fixing with heating rollers by compounding a carrier consisting of resin-coated iron powder and a PP-contg. toner. CONSTITUTION:(A) A carrier wherein resin coating layers of about 0.1-10mu thicknesses are provided on the surfaces of iron powder of about 10-1,000mu grain sizes by using styrene-acrylic type resins, epoxy resins, etc. and (B) a toner wherein 100pts.wt. a binder resin (e.g.; styrene resins, acrylic resins, etc.), about 0.1-50pts.wt. PP of about 80-180 deg.C softening points (ring and ball method) and about 1-20pts.wt. a coloring agent (e.g.; carbon black, nigrosine dye, etc.) are compounded, are mixed, whereby the developer for a magnetic brush method and a cascade method is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developer for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing, and the like.

In electrophotography, a photoreceptor made of a photoconductive element is given a uniform II surface charge in a dark place, and then exposed to light to form an electrostatic charge image. Developed to VIi
Form III.

Methods for developing such an electrostatic charge image in one fold are broadly classified into a liquid IE method and a dry imitation method. The casing development method is indispensable.
It is a method of creating a figurine image using a liquid developer made of fine particles dispersed in a liquid containing various materials and dyes.
Ryoketsu is a developing method that uses a mixture of a coloring agent such as cardan black dispersed in natural or synthetic snow and a carrier such as iron or glass beads. In general, carriers can be divided into insulating carriers and conductive carriers. Oxidized or unoxidized iron powder is used as the conductive carrier. Typical insulating carriers include carrier particles whose surface is coated with insulating W fat, such as magnetic materials such as iron, nickel, and copal. .

Dry development methods include the so-called bristle brush method, impression spray method, and powder cloud method, which use only the above-mentioned toner as a main component and a developer, as well as the method in which a carrier (such as iron powder or glass beads) is used with the toner. There are the so-called bristle brush method and the cascade method in which the mixture is used as a developer.

By these developing methods, electrostatic particles such as cylindrical particles containing charges contained in the 1FII agent adhere to the electrostatic charge, thereby forming a visible image. This visible image is directly transferred onto a photoreceptor or onto a plane image support such as paper using heat, pressure, solvent vapor, etc., and is fixed thereon (3).

The present invention relates to a developer used in the magnetic brush method and the cascade method among the above-mentioned developing methods, that is, an electrostatic image developer composed of a toner and a carrier.

Conventional fusing involves a photoconductive photoreceptor supporting an electrostatically charged image;
Or on an electrostatic recorder, obtained by the current fIIK9)
This is done by directly fusing the toner image, or by fusing the toner image (obtained by development) onto a transfer sheet such as paper from a photoconductive photoreceptor or electrostatic recording medium. be exposed. II) The fusing of the toner image is carried out either by contact with solvent vapor or by heating.

As heating methods, a non-contact heating method using an electric furnace and a pressure bonding heating method using a heating roller are generally adopted. ``Unexamined Patent Publication No. 58-1074'' (1974-1074) ``Toner fixation is carried out by transmitting the toner image surface of the fixing sheet) without pressure contact with the surface of the heating layer.''
9(2) is generally called the heated roller fixing method.

In this method, the surface of the heating plate and the toner image surface of the sheet to be fixed come into pressure contact, so the thermal efficiency when fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. Because it can do this, it is especially suitable for high-speed photography. Extremely effective.

However, in this method, since the heating roller surface and the toner image come into pressure contact with each other in a heated molten mass, part of the toner image adheres to the heating roller surface and is transferred to the next sheet to be fixed. may cause dirt to form. This is a fresh snow offset phenomenon. Therefore, one of the essential requirements for the heat fixing method is to prevent toner from adhering to the surface of the heating roller.

Conventionally, in order to attach toner to the surface of a heated reeler,
For example, the surface of the heating roller is made of a material with excellent mold releasability such as a 7-carbon resin, and a liquid to prevent silicone oil from forming on the surface is supplied to the surface to form a thin film of the heating roller (5). Covering the reward is being done.

Although this method is extremely effective and dangerous in terms of preventing the off-set phenomenon, it generates a foul odor due to heating of the offset prevention liquid, and it is also difficult to supply the off-set prevention casing. Since the mechanism of the 璽寥 device becomes tangential, Ktj
Since high precision is required, the II copying device is expensive.
It has the disadvantage of becoming.

Japanese Patent No. 8Ws52-3304 describes in detail the problems associated with the use of off-cellulin inhibitors, which have been developed to compensate for these drawbacks. By using a toner (containing an off-sera Th' inhibitor), the heating roller
% when not supplying silicone oil to the surface)
It is possible to perform efficient and good heating reeler fixing without causing any phenomena.

Therefore, the mechanism of the fixing device can be simplified.
A high-speed 11 equipped with JS'fk standard equipment.
FLLC+ has the advantage (6) of being able to improve accuracy, stability, and reliability, and also being able to lower the cost.

However, due to the force, toner containing anti-oxidant agents has poor fluidity and does not exhibit free-flowing properties.

When a developer is prepared by mixing the uncoated iron powder carrier with a cylindrical powder containing an anti-off agent, the anti-off agent present on the surface of the powder particles remains for a long period of time. During use, it migrates to the surface of the conductive carrier and can contaminate or adhere to the surface of the carrier, degrading the developer. In other words, in the case of a developer containing a conductive carrier and a cinnamon containing an offset inhibitor, the triboelectric charging properties for the developer become unstable during long-term use, and There is a drawback that fog occurs in the visible 11. In other words, as the developer is used, the off-cera inhibitor adheres to the surface of the starch carrier particles, which increases the electrical resistance of the carrier particles and reduces the bias current, resulting in unstable triboelectrification properties. As a result, the number of image connecting chambers is reduced and fog increases. Therefore, it is necessary to replace the developer at an early stage, which results in high cost.

There has been a strong desire for the development of a highly durable developer containing a component that prevents off-setting to solve the first generation defects.

That is, an object of the present invention is to efficiently perform good heating roller fixing without causing the % occlusion phenomenon when using a fixing roller that does not supply an occlusion prevention liquid to its surface. It is an object of the present invention to provide a developer that can realize high durability using an electrostatic charge image developing solvent.

Motoya S et al. have found that a developer consisting of a resin-coated iron powder carrier and a (containing propylene) developer achieves the above object.

That is, according to the present invention! In the structure of the developer consisting of a resin-coated iron powder carrier and a toner containing polypropylene used in the image mK, in its structure tE, the powder contained in the toner surface is resin-coated. Compared to the case where an unprecedented carrier is used, it is possible to transfer or fuse to the die surface of the carrier, which is superior in durability. They found that it is suitable.

The resin-coated carrier may have a spherical shape or irregularly carved shape, and may be conductive or insulating as a resistor, but is preferably insulated and spherical. coated carriers are optimal.

In the present invention, O2 is used to coat the iron powder particles of the carrier.
*Vg includes styrenes such as p-tetrastyrene and methylstyrene; halogenated vinyl such as vinyl chloride, vinyl bromide, and vinyl heptadide; #II: vinyl acetate, vinyl propionate, vinyl benzoate; S*vinyl Vinyl esters such as acrylic methyl, ethyl acrylate, F-butyl acrylate, isobutyl acrylate, dodecyl acrylate, octyl acrylate, acrylic 113
- Ester of mono-methylene aliphatic monocarboxylic acid such as methyl methacrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate; (9) Vinyl ethers such as acryl diFlyl, methacryl di)lyl, acrylamide, vinyl methyl ether, vinyl isobutyl ether, and vinyl ethyl ether; Polymerized homopolymers or other resins include epoxy W resin, rosin-modified phenol-formalin resin, and cellulose 11! resin, polyether resin, polyvinyl butyral resin, polyester resin, styrene-butadiene resin, urethane resin, polyvinyl formal resin,
Melamine resin, glycerin key) 4! Blending resins such as fluorine resin, Teflon, etc. by yourself:
can be used.

Among these, styrene-acrylic resins II (e.g. LF! Styrene-methyl methacrylate, styrene-butyl methacrylate-Y, etc.), epoxy resins, styrene-butaduene resins, butyral resins, cellulose resins, etc. are especially used. Useful.

In addition, when the photoreceptor is a highly charged material made of organic photoconductive substances, cadmium sulfide, etc. (10), resins such as fluororesin such as Teflon, vinyl chloride vinegar-vinyl resin, and polyester All1 resin may be used. suitable.

In order to manufacture the carrier used in the present invention using W, the above-mentioned resin is dissolved in a solvent to prepare a coating liquid, and this coating liquid is applied to the surface of iron powder serving as carrier core particles. For this application, Kti, dipping, spraying, etc. can be used, but the fluidized bed method is particularly preferred. This fluidized bed method uses a pressurized gas flow that rises in a fluidized bed device to raise and suspend the nuclear particles to an equilibrium height, and then apply the coating while the nuclear particles fall again. This is a method in which the liquid is applied to each particle by spraying from above, and this is repeated to form a coating film of a desired thickness, and by this method it is possible to uniformly apply the liquid to each particle. tW having good compatibility may be mixed and dissolved in the coating liquid.

The solvent used in the above may be any solvent as long as it dissolves the resin, such as alcohols II such as methanol, ethanol, butanol, and isoprobanol (11); p-genated hydrocarbon-;
) Aromatic hydrocarbons such as luene and xylene*, acetylene,
methylstyrene, etc.; other te)rahides a)
A mixture of these solvents and a zelkova solvent such as dioxane and dioxane are used.

In the above, the iron powder as the contact particle has a particle size of 1
The thickness of the resin coating layer is preferably 0 to 1000 microns, especially 20 to 30 microns, and the thickness of the resin coating layer is preferably 0.1 to 10 microns, especially 2 to 5 microns.In the present invention, ) As a component of the binder, styrenes such as p-chlorostyrene and methylstyrene; acrylic methyl, ethyl acrylate, n-butyl acrylate, acrylic isobutyl, methyl methacrylate, Methyl methacrylate, butyl methacrylate, etc. - Methylene aliphatic monocarboxylic acids 1lI11! Homo l polymerized with which monomer
In addition to this, resins such as 1-rivinyl petitral resin and JP-A-58-10749 (4) styrene-butadiene resin can be used alone or in a blend.

The developer according to the present invention contains polypropylene (described later) in the binder as described above, and further contains a property improver added as necessary.

As a coloring agent, carbon black, nicrosine dye (
C, LA50415 B), Aniline Blue (C,
1,450405), force 1k: r tilvRy-
(C, I.

A ass@t Bll@3), Ripm Yellow (C, ■, / 14090) f) le) 57'J
Full-(C, 1, A77103), f-! & Nt I A/ L/ Rad (C, 1, A26105)
, + /9 x * - (C, 1, A47005)
, l+Renflu-Clo5i)' (C, 1, A3201
5), 7#oshi72>Blue (C,1,A 741
60), Ma5 Kite! Lean t l't lay) (C,
T, A 42000),? ＞F15'/ri (C
, 1, A 77266), t”-Zhenga k (C,
1° square 454353, mixtures thereof, and others. It is necessary that these colorants be contained in a sufficient proportion to form a sufficient visible image of charcoal production (13), and usually 1 part by weight of the binder is used.
~20 parts by weight S lean.

In addition, JIB, which is contained in Shiner grains,
K 2531-1960 K The cutting point when measured by the ring and ball method specified by K is 80 to 180 °C, preferably 10
The temperature is 0 to 160°C.

The ratio of this polypropylene to the binder is:
Usually o, i -s o weight attack, preferably l~2
031 quantity arc.

Furthermore, toners containing polypropylene generally tend to have lower fluidity. Therefore, the fluidity improver may be added in an amount of 0.1 to 5% by weight, preferably 0.2 to 2% by weight. As the fluidity improver, there may be used "Fine Powdered Sung Silica rR-972" commercially available from Nippon Aerosil Co., Ltd., and the like.

The actual 11iNK of the present invention will be explained below, but the present invention is not limited thereto.
ROCARIA 1 Styrene-methyl methacrylate (14) with an average molecular weight of 150,000. Prepare a coating solution by dissolving resin 5 in methyl ethyl ketone 30. IIcf (manufactured by Nippon Iron Powder Co., Ltd.) was placed in the coating solution, and dried by blowing hot air while stirring in a II photographic film with the supernatant liquid removed, and then the powder was placed in an oven at a temperature of 100°C. Heat treated for 2 hours, then W
A carrier 1 having a fat coating was obtained. This carrier 110
The volume resistivity was F113X1ψg-.

In addition, the sample 1 was placed in a container with "volume resistivity", an insulated area of 1 d, a depth of l scratched recess, and an inner circular bottom surface of which was electrodeposited with brass.
The value was measured under the condition that K was added and a brass electrode of Iw4 was placed on the sample layer from above.

2) Carrier 2: Dissolve 11113 g of s-acid sm cellulose in 300-300 g of methyl ethyl ketone.
#IF the steel iron powder rDsP-179DJ (Dowa Iron Powder Company 11) IEt of 00 mesh! Pour the powder into the coating liquid, and after the supernatant liquid has cooled down, stir it with a photographic vat (15) and dry it by blowing hot air, then heat the powder to a temperature of 120
A heat treatment was performed in an oven at .degree. C. for 1 hour, thereby obtaining a carrier 2 in which the resin coating was blinded. The volume resistivity ti of this Q+'JA2 was 4.5 x 10'Ω·-.

3) Ima Yaria 3 2004001'y was applied using a coating solution in which 3g of methacrylic methyl-acrylic ethyl copolymer resin with an average molecular weight of 100,000 was dissolved in 300% of methyl ethyl ketone.
Shu fD sintered iron powder “〒IFVSJ (manufactured by Nippon Iron Powder Co., Ltd.) 1k
A carrier 3 having a resin coating was made in the same manner as the carrier 10W structure except that a carrier 3 was used. Volume resistivity t! of this carrier 3! It was 1.8 x 10” IJ-1.

4) Dissolve 1120 g of carrier 4 in 300 g of methyl ethyl ketone to prepare a coating solution, and use a fluidized bed 11 w to make a ball-carved mold with an average particle diameter of 10 mm) 1 (
, sprayed with fluid drying S thinner at 60℃,
Next, the powder was heat-treated in an open environment at a temperature of 100° C. for 2 hours, thereby obtaining a carrier 4 having a resin coating. The volume resistivity of this carrier 40 was -14 g.- or more.

5) Carrier 5 Use L-vinyl butyral resin "Esletta 1" (Sekisui Chemical Co., Ltd. II) instead of polyurethane resin to make Carrier 5 with a resin coating similar to the W construction of Carrier 4. I got this carrier 50 volume @ resistive t! 6
．． It was 8 XI 011g.-.

6) Styrene-butyl methacrylate with an average molecular weight of 130,000)
IrI! For coating Il! Used as It, iron powder r08F
-13SCJ (manufactured by Neo Iron Powder Co., Ltd.) twAZl! A carrier 6 having a resin coating was obtained in the same manner as carrier 40wII. These 60 carriers II8! i! The resistance was 1014 R61 or more.

[)Nar l1li) 1)) Nur 1 Polystyrene IIf fat [Picolastic D-125
1 (manufactured by Etsuso Corporation), 5 parts by weight of Robylene [Viscol 660PJ (manufactured by Sanyo Kagakuin Co., Ltd.), and 10 parts by weight of carbon black.
Mixed with Lumil, according to the usual method of manufacturing
A toner with an average particle size of 11 microns was obtained by kneading, pulverizing, and classifying, and in order to improve Kll mobility, one weight of hydrophobic silica rR-972J (manufactured by Nippon Aerosil Co., Ltd.) was added and dispersed to form a toner. It was set as l.

2) )ner 2 Styrene-acrylic resin “Eslec” (Tanesui Kagaku I!
1. ll1), 4 parts by weight of low softening point polypropylene [Viscol 550PJ (Sanyo Chemical Industries, Ltd. II), and 10 parts by weight of carbon black.
A toner having an average particle size of 11.2'' was obtained in the same manner as above, and 0.5% by weight of hydrophobic silica "R-972" was added thereto and dispersed to obtain Toner 2.

3)) 100 parts by weight of Nur3 Giriester IIFII (a large experimental sample obtained from Kao Soap Industries) and l Reprovir C18.
) Using 3.5 parts by weight of Viscol 660I'J and 10 parts by weight of carbon black, a cylinder with an average particle size of 12.1 microns was obtained in the same manner as Toner 1.
Toner 3 was prepared by adding and dispersing 1.5 weight of aqueous silica "R-972".

4)) Ner 4 100 parts by weight of styrene-acrylic resin "Eslec 1 (manufactured by Tanezu Kagaku Co., Ltd.) and polypropylene [Viscol 66
2 parts by weight of 5 parts by weight of 0PJ and 10 parts by weight of carbon black
Toner 4 having an average particle diameter of ti and s microns was obtained in the same manner as Toner 1.

One of the carriers 1 to 6 described above and one of the toners 1 to 4 are combined as shown in the table below, and mixed in a ratio that gives the toner concentration C violet amount shown in the table. 6! The electrostatic charge image development side of the present invention was prepared, and an electrophotographic copy book [1-B
ixWr modified type) 1 (manufactured by Konishi Rokuma Kogyo Co., Ltd.),
A durability test was conducted on each developer by continuous copying. Result F! ! ! This is a trace back to iIK.

(19) From the results shown in the table above, it can be concluded that the electrostatic charge image of the present invention is 5! In addition, it has great durability as it can achieve good development without causing capri even after being subjected to development many times.Moreover, there is no image staining due to off-sera), and it has excellent WVM. You can get a meeting.

Comparative Example Made in the same manner as Nurer 1 using 100 parts by weight of styrene-acrylic*wr Esrec J (manufactured by Il Suikagaku Co., Ltd.), 5 parts by weight of Boriptapyrene (Viscol 660PJ, and 10 parts by weight of carbon black). Average particle size 12.
Add 5 parts by weight of 6 Mikup of Cina to 1FVJ (1FVJ) of iron powder.
When the developer was mixed with 95 parts by weight of a carrier made by Nippon Iron Powder Co., Ltd. (If) to give a developer of 10%, and the same durability test as in the example was conducted using this developer, the number of IIv times reached 10,000 times. The pre-KII image blurring occurred, making it unusable for practical use.

Claims (1)

[Claims] 1) An electrostatic image developer characterized by comprising a carrier consisting of iron powder particles coated with a resin and a toner containing 19-propylene.