JPS63167374A - Magnetic toner for electrophotography - Google Patents

Abstract

PURPOSE:To permit development of a magnetic toner consisting of a binder resin, coloring material and magnetic powder by a simultaneous method and transfer thereof to plain paper by a corona transfer method by coating an electric charge transfer carrier on the surface of said toner. CONSTITUTION:The charge transfer carrier 5 is coated on the surface of the magnetic toner 1 consisting of the binder resin 2, the coloring material 3 and the magnetic powder 4. The conductivity of the toner 1 on a sleeve as a function of the rotating speed and impressed voltage of the sleeve is thus improved by the friction and agitation which arise at the time of forming a magnetic brush and, therefore, the provision of such a toner which has the electrical conductivity at the time of development and an insulating characteristic at the time of transfer is permitted. The toner which permits corona transfer as an ordinary toner at the time of transfer is thereby realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to magnetic toners used in electrophotography.

[Conventional technology]

In recent years, non-non-pact methods with less noise have been attracting attention as a means of printing image information.

Among them, there is an electrophotographic process capable of high-speed printing, and an all-needle simultaneous process (I# 153957/1986) is known which simplifies and downsizes the process.

This is done by applying a full bias voltage, using a brand of conductive magnetic toner, and rubbing the entire surface of the photoconductor during exposure to simultaneously perform reverse development and exposure. In other words, the amount of charge injected into the toner in contact with the photoconductor surface by the bias voltage when the photoconductor acts as an insulator (unexposed part) and when it acts as a conductor (ME part S). There is a difference in
The difference in the amount of charge becomes a difference in the electrostatic adhesion force to the photoconductor surface, making development possible.

[Problem that the invention seeks to solve]

However, due to the conductivity of the toner used in the simultaneous method, the charge on the toner is neutralized in a short relaxation time, and the residual charge is completely lost and the electrostatic adhesion to the paper is lost. It is necessary to fabricate the entire toner structure that has an insulating property t1.

It is an object of the present invention to provide a toner that can be developed in a simultaneous process and transferred to plain paper by a corona transfer process.

[Means for solving the problem] The electrophotographic magnetic toner of the present invention is characterized in that a charge transport carrier is deposited on the surface of the magnetic toner, which is composed of a binder resin, a colorant, and a magnetic powder. shall be.

In the toner of the present invention, known magnetic powders include magnetite, hematite, ferrite, iron, cobalt, etc.
Alloys such as nickel and manganese, compounds, and other magnetic powders can be used alone or in combination.

In the present invention, in addition to the known black carbon black, graphite, and nigrosine pigments used as colorants, other colors such as blue phthalocyanine blue can be used.

Furthermore, as a binder resin, known styrene resin or its polymer, polyester, polyethylene, polypropylene, acrylic resin, polyvinyl acetate, polyurethane, etc.
Polyamide, epoxy resin, polyvinyl chloride, polyvinyl butyral, boria-r (Dotatami rosin L modified rosin e
Terpene resins, phenolic resins, aliphatic or aliphatic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, etc. can be used alone or in combination. Other fluidity modifiers used include colloidal silica, hydrophobic silica, silicon face, metal soap, nonionic surfactants, and polyvinylidene fluoride fine particles.

The charge transport carrier as used in the present invention is a substance that completely transports electrons and holes, such as an electron-donating substance and an electron-accepting substance. Among these, known electron-donating substances include nigrosine-based electron-donating dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary ammonium salts, alkylamides, chelates, pigments, and fluorine treatment activators. As electron-accepting substances, chlorinated paraffin, chlorinated polyester, polyester with excess acid groups,
Copper phthalocyanines such as sulfodylamine and chloranil are known.

[Effect]

According to the above configuration of the present invention, the conductivity of the toner on the sleeve improves as a function of the rotational speed of the sleeve and the applied voltage due to the friction and agitation that occur when forming the magnetic brush. Insulating properties during transfer! We can provide toners that

〔Example〕

Example 1 Acrylic resin (Delpet 6aw, Asahi Kasei) 100 tons
s, -rf Netai)' (E P T -1000゜Toda Kogyo) 501it Miyako, Car d (N Black (M-1
00, Mitsubishi Kasei) 10 parts by weight were mixed, kneaded using a screw extruder, and coarsely ground using a stamp mill. Furthermore, after crushing with a jet mill, it is subjected to air classification.
Toner with a particle size of 30 μm was collected. 10 parts by weight of magnesium naphthenate were mixed with 160 parts by weight of the obtained magnetic toner in a ball mill, and then dried in a flash dryer. It was spheroidized using

FIG. 1 is a diagram showing the toner produced according to this example. Binder resin 21 Coloring material 5. A charge transport carrier is uniformly coated on the magnetic toner consisting of magnetic powder 4.

FIG. 2 shows how development is performed by the simultaneous method using the toner of the present invention. In the figure, the same elements as in FIG. 1 are given the same numbers. Original conductor layer 6. Transparent conductor j-7. The image forming part 9, which has transparent support layers 8 DEG laminated in this order, is subjected to image exposure 11 as it moves in the direction of the arrow 10. Toner magnetic roller 12 and sleeve 1
The toner that has come into contact with the image forming portion 9 by the well-known magnetic brush formed from the magnetic brush 3 is subjected to a strong agitation force as the sleeve moves in the direction of the arrow 14. Since a bias voltage 15 is applied on the sleeve, charge is transported by mutual contact of the charge transport carriers on the toner, and the toner becomes conductive. At this time, the amount of charge injected into the toner is different between the exposed area and the unexposed area of the photoconductor layer, resulting in a difference in the electrostatic adhesion force of the toner to the surface of the image forming area, and development is performed. It will be done.

FIG. 3 shows how toner is transferred by the corona transfer method according to the present invention. Developed image forming section? A transfer paper 17 is placed on the surface of the transfer paper, and ions having a polarity opposite to that of the toner 1 are injected into the toner 1 by a corona transfer device 18 from the back side of the transfer paper. At this time, normal electrostatic transfer is performed. The transferred paper is conveyed in the direction of arrow 19. The sleeve speed of the toner prepared in this example at − foot bias f bias voltage? Figure 4 shows the resistance change when changing the resistance.

It can be seen from this that when the sleeve rotates, charge is transported by stirring and mixing, which shows sufficient conductivity for development, and when the sleeve speed is 0, that is, during transfer, it shows sufficient insulation, making corona transfer possible. . A clear image was obtained with good reproducibility by the simultaneous method using the toner prepared in this example.

Example: 160 g of the magnetic toner prepared in Example 1 was mixed with 10 parts by weight of chlorinated polyester in a ball mill, and then spheroidized using a flash dryer. Using this, a toner image was formed in the same manner as in Example 1, and seven printings were performed in a simultaneous process using corona transfer, and a clear image was obtained with good reproducibility.

Examples & Polystyrene (Touplex, Mitsui Toatsu) 100 parts by weight LDPR (Polyethylene 130, Hoechst AG)
100 parts by weight magnetite (S
L-520, Titanium Kogyo Co., Ltd.) 100 parts by weight were mixed together, kneaded using a screw extruder, coarsely ground using a stamp mill, finely ground using a jet mill purple, and then air classified into particles with a particle size of 5 to 60 μm. Collected toner. 5004 iJt parts of the obtained magnetic toner was mixed with 5 parts by weight of ultrafine tetrafluoroethylene powder in a ball mill, and the mixture was spheroidized using a flash dryer.

The toner obtained in this example was printed using the same simultaneous process as in Example 1, with clear re-extension throughout the printing process. Obtained.

Although the above description describes the number of electron-donating substances or electron-accepting substances, it is clear that the present invention can be applied to any substance that can accept or donate all electrons or holes.

〔Effect of the invention〕

As described above, according to the present invention, by breaking the surface layer of the magnetic toner into a charge transport carrier, the toner can be used for charge transport by fluidizing the toner as the sleeve rotates when a bias is applied. It can be made into a conductive violet toner, and during transfer, it can be used as a normal toner to achieve corona transfer. When used in the present toner all-simultaneous method, it is possible to realize a printing device W' with a greatly simplified process, which has a great effect on cost reduction and miniaturization.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the magnetic toner for single-child photography according to the present invention. The second decoy is a diagram showing how development is performed by a simultaneous method using the electrophotographic magnetic toner violet according to the present invention. FIG. 3 shows how the electrophotographic magnetic toner of the present invention is transferred. Figure shown. FIG. 4 is a diagram showing the toner resistance when the rotating speed of the sleeve is changed under a -contrast applied voltage when all development is carried out using the magnetic toner sound for electrophotography according to the present invention. 1... Toner 2... Binder resin 5... Coloring material 4... Magnetic powder 5... Charge transport carrier 6... ... Photoconductor layer 7 ... Transparent conductor layer 8 ... Transparent support layer 9 ... Image forming section 10 ... Image forming section Movement direction 11...
・Image exposure 12...Mag roller 13...Sleeve 14...Mag roller rotation direction 15...
...Bias voltage 16...Movement direction of image forming section 17...
・Transfer paper 18...Corona transfer machine 19...Movement direction of transfer paper Applicant: Seiko Epson Corporation No. 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A magnetic toner for electrophotography, characterized in that a charge transport carrier is coated on the surface of a magnetic toner comprising a binder resin, a colorant, and magnetic powder.