JPH09134032A - Magnetic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure satisfactory properties of an image, sufficiently high fixability even in high-speed printing and satisfactory preservability and to prevent the contamination of a head by incorporating a specified compd. SOLUTION: This magnetic toner contains 0.1-5.0 pts.wt. compd. represented by the formula [Ti(OCOCn H2n+1 )2 -O]x [where (n) is an integer of 14-20 and (x) is an integer of 2-6]. Since a magnetic head performs recording under very slight levitation from the surface of a magnetic recording medium, when a toner having a large quantity of electric charges by triboelectric charge is used, it sticks to the head, levitation is made unstable and the interval between the medium and the head is made ununiform to deteriorate properties of an image. The quantity of electric charges of the magnetic toner is preferably regulated to -5 to +5μC/g. Since the compd. is contained, the dispersibility of a magnetic substance is improved, the melt viscosity of a resin can be reduced and adhesion to paper is improved. As a result, fixability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used in electrophotography, electrostatic recording, electrostatic printing, magnetic recording, etc., and more particularly to a toner for developing a magnetic latent image used in magnetic recording.

[0002]

2. Description of the Related Art A magnetic recording method is a method of writing a magnetic latent image on a magnetic drum, which is a recording medium, using a magnetic head, developing with a one-component toner containing magnetic powder, transferring, and fixing. (See JP-A-54-32328, etc.). With this method, a large number of copies can be obtained by forming a magnetic latent image once, and there is no fatigue of the photoconductor unlike the electrophotographic method, and there is no need to replace the photoconductor after every tens of thousands of copies. It has an advantage that maintenance is easy.

Recently, a printer that generates less ozone has been desired due to the problem of environmental damage. However, in this method, ozone is not generated because a transfer process is performed by pressing a recording medium such as paper with a resin roller from the back side. It is a method that has received very little attention recently, with few. The toner for developing a magnetic latent image used in this method contains a fixing resin to be fixed on the final recording paper and the like, and a magnetic powder satisfying magnetic properties enabling development of the magnetic latent image and transportability to a development site. . Further, due to the recent demand for high image quality, sharpness of characters has been demanded, and in particular, the demand for energy saving and high speed has been increasing in recent years, and there has been a demand for a toner which is sufficiently fixed even at low temperature and has good imageability. .

[0004]

Since the magnetic toner used in the magnetic recording method requires the magnetic powder necessary to visualize the magnetic latent image, it contains a relatively large proportion of the magnetic powder. . Further, for the purpose of high-speed printing, the magnetic toner contains a resin having a relatively low softening point and a release agent having a low softening point. However, when a resin having a low softening point and a release agent having a low softening point are contained, the margin for storage is small. The problem to be solved by the present invention is to provide a magnetic toner having good imageability, sufficient fixability even in high-speed printing, good storage stability, and free from head stains.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have solved the above problems and have good imageability, sufficient fixability even at high speed printing, good storage stability, and magnetic head toner that does not cause head contamination. In order to provide the toner, the problem was solved by providing a toner containing 0.1 to 5.0 parts by weight of the compound of the following general formula (I). _{[Ti (OCOC n H 2n + 1} ) 2 -O ] _x (I) (n in the formula is an integer of 14 to 20, x is an integer of 2-6.) Magnetic toner formula (I) By containing the compound (1), the dispersibility of the magnetic material is improved, the melt viscosity of the resin can be lowered, the adhesion to paper is improved, and the fixability is improved as a result.

Usually, the fixing method is a thermal contact method,
The thermal non-contact method, the pressure method and the like can be mentioned, but the present invention adopts the thermal contact method. In the thermal contact method, it is important that offset does not occur, and the toner usually contains 0.1 to 5 parts by weight of a release agent such as polyolefin. However, the polyolefin tends to reduce the fluidity of the toner and cause soft blocking during storage.

The compounds of the general formula (I) themselves have a release effect and do not require polyolefins, but can also contain small amounts of polyolefins and exert a sufficient release effect and offset. It can be prevented. Further, the compound of the general formula (I) hardly causes soft blocking. This makes it possible to prevent deterioration of fluidity of the toner and soft blocking, which are mainly caused by the polyolefin.

By containing 0.1 to 5 parts by weight of the compound of the general formula (I), offset can be prevented, deterioration of fluidity and soft blocking can be prevented, and storage stability can be greatly improved. . Furthermore, since the compound of the general formula (I) is usually a solid and can be added at the same time when mixing the magnetic substance, the resin, etc., it is necessary to previously attach it to the magnetic substance surface like a general titanium coupling agent. Absent.
Therefore, no extra step is required. The compound of general formula (I) is commercially available and can be easily obtained, for example, as Matsumoto Pharmaceutical Co., Ltd. (manufactured by ORGATICS TPHS).

The magnetic toner according to the present invention will be described in more detail. As the resin used in the present invention, most resins generally used for electrophotography can be used, and polystyrene resin, styrene / acrylic resin copolymerized with various esters of styrene and acrylic acid or methacrylic acid, and these styrene-based resins Examples include polymers obtained by partially cross-linking the polymer, and further polyester resin, epoxy resin, polyamide resin, polyolefin resin, ethylene-vinyl acetate copolymer resin, and the like.

These resins can be used alone or as a mixture of several kinds, and are generally selected and used according to the fixing method. The magnetic powder used in the present invention includes Ni, Z
Examples of the metal compound include n, Cu, Co, Fe, Mg, ferrite Fe, magnetite, and γ-fematite.
The ratio of the magnetic powder in the magnetic toner of the present invention is preferably in the range of 50 to 70 parts by weight. If the ratio of the magnetic powder is less than 50 parts by weight, the magnetic force of the toner becomes weak, the toner transportability is deteriorated, and the fog tends to increase, which is not preferable. On the other hand, if the amount is more than 70 parts by weight, the fixing property is lowered, which is not preferable.

Further, since the magnetic head records on the surface of the magnetic recording medium while slightly floating, the toner adheres to the magnetic head when the triboelectric charge amount of the toner is large, and the floating becomes unstable. And the magnetic head are not evenly spaced. Therefore, the triboelectric charge amount of the magnetic toner is preferably -5 to 5 [mu] C / g because the image quality is deteriorated.

As a method for controlling this, there is a method using an external additive and / or a charge control agent. By adding inorganic fine particles such as hydrophobic silica, aluminum oxide, and titanium oxide, the triboelectric charge amount of the magnetic toner is -5 to 5 μC /
It can be controlled to g. The surface of the inorganic fine particles in this case may be treated with a coupling agent or the like. It is clear that similar results can be obtained even when a plurality of these inorganic fine particles are used. Examples of commercially available products that can be used as external additives include "RA20" manufactured by Nippon Aerosil Co., Ltd.
OH "and" HDKH2050EP "and" HDKH2015EP "manufactured by Wacker Chemicals East Asia Co., Ltd.
Hydrophobic silica such as "RFY" manufactured by Nippon Aerosil Co., Ltd.
Inorganic fine particles such as aluminum oxide such as "-C" and titanium oxide such as "T-805" manufactured by Nippon Aerosil Co., Ltd. can be used.

Further, depending on the charge control agent, -5 to 5 μC /
It is also possible to control to g (Japanese Patent Laid-Open No. 3-2
10568). Examples of the charge control agent include nigrosine, quaternary ammonium compounds, triphenylmethane dyes and the like, and these can be used. Examples of commercially available charge control agents include "Bontron N-01" and "Bontron N-04" manufactured by Orient Chemical Co., Ltd. and "Copy Blue PR" manufactured by Hoechst Japan Co., Ltd. As described above, the charge amount of the toner can be controlled by using the external additive and the charge control agent.
In the present invention, a polyolefin may be contained in order to improve offset and fixability. Polyolefins usable in the present invention include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polypropylene-
Examples thereof include a methyl acrylate copolymer, a polypropylene-vinyl chloride copolymer, a propylene-ethyl methacrylate copolymer, a propylene-vinyl acetate-methyl acrylate copolymer and the like.

Carbon black and other dyes and pigments can be used as the colorant, and can also serve as an electric resistance adjusting agent.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples. Example 1 KBF-100S 250 parts by weight (Kanto Denka Kogyo ferrosoferric oxide) FC-051 120 parts by weight (Mitsubishi Rayon polyester resin) FC-344 20 parts by weight (Mitsubishi Rayon polyester resin) Organix TPHS 4 parts by weight Parts (Matsumoto Pharmaceutical Co., Ltd.) Copy Blue PR 3 parts by weight (Hoechst Industry charge control agent) The above components are mixed, melt-kneaded, cooled to room temperature, coarsely pulverized and medium pulverized, then finely pulverized and classified by a jet mill. A magnetic toner having an average particle size of 9 microns was obtained. 10 for this toner
[RFY-C] for 0 parts by weight (Japan Aerosil Co., Ltd.)
0.3 part by weight of aluminum oxide) was externally added and mixed to obtain a magnetic toner of Example 1. The triboelectric charge amount at this time was -2.6 μC / g.

Comparative Example 1 KBF-100S 250 parts by weight (Kanto Denka Kogyo ferrosoferric oxide) FC-051 120 parts by weight (Mitsubishi Rayon polyester resin) FC-344 20 parts by weight (Mitsubishi Rayon polyester resin) High wax NL-500 10 parts by weight (polyethylene wax manufactured by Mitsui Petrochemical Co., Ltd.) Copy Blue PR 3 parts by weight (charge control agent manufactured by Hoechst Industry) was prepared in the same manner as in Example 1 to obtain a magnetic toner. The triboelectric charge amount at this time was -1.8 μC / g.

Example 2 KBF-100S 250 parts by weight (Kanto Denka Kogyo ferrosoferric oxide) FC-051 120 parts by weight (Mitsubishi Rayon polyester resin) FC-344 20 parts by weight (Mitsubishi Rayon polyester resin) Organix TPHS 4 parts by weight (Matsumoto Pharmaceutical Co., Ltd.) High wax NL-500 4 parts by weight (Mitsui Petrochemical Industry polyethylene wax) Copy Blue PR 3 parts by weight (Hoechst Industry charge control agent) Other than using the above components, carried out In the same manner as in Example 1, the magnetic latent image developing toner of Example 2 was obtained. The triboelectric charge amount at this time was -2.1 μC / g.

Comparative Example 2 250 parts by weight of KBF-100S (Kanto Denka Kogyo ferrosoferric oxide) FC-051 120 parts by weight (polyester resin manufactured by Mitsubishi Rayon) 20 parts by weight of FC-344 (polyester resin manufactured by Mitsubishi Rayon) High wax NL-500 20 parts by weight (polyethylene wax manufactured by Mitsui Petrochemical Industry) Copy Blue PR 3 parts by weight (charge control agent manufactured by Hoechst Industry) Magnetic toner of Comparative Example 2 in the same manner as in Example 1 except that the above components were used. And The triboelectric charge amount at this time was -1.2 μC / g.

Next, MG-810 manufactured by Iwasaki Tsushinki Co., Ltd.
The magnetic toners obtained in each of the above Examples and Comparative Examples were subjected to image output with a 0 type printer. Table 1 shows the results.
The evaluation method is as follows. 1) Image Density Using a Macbeth reflection densitometer RD-918 (manufactured by Sakata Shokai), a solid density of 1 cm × 1 cm was measured. 2) Triboelectric charge amount 100 parts by weight of surface iron oxide powder ([TEFV] manufactured by Powder Tech Co., Ltd.) having a particle size of 200 to 300 mesh and 3 parts by weight of each magnetic toner are mixed in a 100 ml glass container for 10 minutes, and Toshiba is mixed. It was measured with a blow-off charge amount measuring device manufactured by Chemicals. 3) Fixing ratio The reflection density of the printed solid of 1 × 1 cm was measured, and after the cellophane tape was applied and pressed at a pressure of 10 kg / cm from above, the peeling reflection density was measured at a speed of 1 cm / s. The result was calculated as (reflection density after removing cellophane tape) / (reflection density before removing cellophane tape) × 100
(%). 4) Storability After the magnetic toner was left in a constant temperature bath at 45 ° C. for 168 hours, the cohesion degree was measured using a powder tester manufactured by Hosokawa Micron.

[0020]

[Table 1] As shown in Table-1, good offset and fixability,
Preservability is improved. The magnetic toners obtained in the respective examples do not increase character dust and fogging even after repeated copying, a good image is obtained, and sufficient fixing property is obtained. Further, the toner is not attached to the magnetic head, which is good.

[0021]

According to the present invention, it is possible to provide a stable and good image having good imageability, sufficient fixability even at high-speed printing, good storability, and no head stain.

Claims (2)

[Claims] 1. A magnetic toner mainly composed of a binder resin and magnetic powder, containing 0.1 to 5.0 parts by weight of a compound represented by the following general formula (I). _{[Ti (OCOC n H 2n + 1} ) 2 -O ] _x (I) (n in the formula is an integer of 14 to 20, x is an integer of 2-6.) 2. The triboelectric charge amount of the magnetic toner is -5 to 5 .mu.C.
The magnetic toner according to claim 1, which is in a range of / g.