JP3102307B2 - Toner for developing magnetic latent images - Google Patents

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 In a magnetic recording method, a magnetic latent image is written on a magnetic drum as a recording medium using a magnetic head, developed with a one-component toner containing magnetic powder, transferred, and fixed. For example, it is described in JP-A-54-32328 (JP-B-57-46795). This method
A large number of copies can be obtained by forming a magnetic latent image once, and there is no photoreceptor fatigue unlike the electrophotographic method, and there is no need to replace the photoreceptor every tens of thousands of copies, and maintenance is required. It has the advantage of being easy.

In recent years, a printer that generates less ozone is desired due to the problem of environmental destruction. However, in this method, a process in which a resin roller or the like is pressed against the back of a recording medium such as paper with a resin roller is used. It rarely occurs and is a method that has recently received special attention. The toner for developing a magnetic latent image used in this method contains a fixing resin to be fixed on the final recording paper or the like, and a magnetic powder satisfying magnetic properties enabling development of the magnetic latent image and transportability to a development site. . Furthermore, the sharpness of characters has been required due to the recent demand for higher image quality, and in addition, the demand for energy saving and high speed has been increasing in recent years. I was

[0004]

With respect to the transfer process,
In a process in which a recording medium such as paper is pressed against a back surface of a recording medium such as paper with a resin roller or the like, there is a disadvantage that the image density greatly changes depending on the type of the recording medium and the paper thickness, and the sharpness of characters changes. Further, when the transfer voltage is increased, the change due to the type of recording medium and the paper thickness is reduced, but a discharge phenomenon occurs on the toner and the paper surface, and the transfer voltage cannot be increased. As a result, the reflection density decreases. there were.
Therefore, it is preferable that the electric resistance value of the toner is relatively low.

As a method for lowering the electric resistance value of such a toner, a method of adding a conductive substance to the toner surface has been proposed as described in Japanese Patent Application Laid-Open No. 2-7071. However, these methods require extra steps and are inferior in workability as compared with normal toner production, and furthermore, the conductive material is separated from the toner, and adheres to the non-image area and the character is less sharp. Met.
Further, as described in Japanese Patent Application Laid-Open No. 4-151166, the method of containing carbon black to lower the electric resistance uses carbon black having a large specific surface area and a large amount of oil absorption, so that the fixing property is lowered and the character The sharpness was poor.

In order to solve such a problem, the inventors of the present invention have good image quality irrespective of the type of paper, have sufficient fixability even at high-speed printing, have good storability, and have good head contamination. The present invention has sought to provide a toner for developing a magnetic latent image which does not cause any problem.

[0007]

Means for Solving the Problems To solve the above problems, the present inventors have good image quality without changing the image quality depending on the type of paper, and have sufficient fixability even at high speed printing. An object of the present invention is to provide a magnetic latent image developing toner which has good storage stability and does not cause head contamination. Specifically, an object of the present invention is to provide a toner containing a quaternary ammonium salt group-containing copolymer in an amount of 1 to 8 parts by weight and having an electric resistance value in a range of 10 ⁸ to 10 ¹² Ωcm.

The toner for developing a magnetic latent image according to the present invention will be described in more detail. The quaternary ammonium salt group-containing copolymer used in the present invention is as described in claim 1.
As corresponding to, for example, JP-A-4-19830
8, JP-A-6-271780 , JP-A-6-1797
No. 16 are mentioned.

The magnetic latent image developing toner of the present invention preferably contains a quaternary ammonium base-containing copolymer in a proportion of 1 to 8 parts by weight. When the proportion of the quaternary ammonium salt group-containing copolymer in the magnetic latent image developing toner of the present invention is less than 1 part by weight, the effect of lowering the electric resistance value is reduced, and as a result, the transfer voltage cannot be increased, For example, when an image is output on a recording medium such as thick paper, a decrease in reflection density is observed. On the other hand, if it is more than 8 parts by weight, there is a disadvantage that storage stability is reduced.

As the resin used in the present invention, most resins generally used for electrophotography can be used.
Polystyrene resin, styrene / acrylic resin copolymerized with various esters of styrene and acrylic acid or methacrylic acid, and those obtained by cross-linking part of these styrene-based polymers, furthermore, polyester resin, epoxy resin, polyamide resin, polyolefin resin , And ethylene
And vinyl acetate copolymer resin. These resins can be used alone or as a mixture of several kinds. These resins are selected and used according to the fixing method, and are generally used in a range of 20 to 60 parts by weight for the toner for developing a magnetic latent image.

The magnetic powder used in the present invention includes Ni,
Metal compounds such as Zn, Cu, Co, Fe, Mg, ferrite Fe, magnetite, and γ-fematite ;
Average particle size 0.20 to 0.45 μm, coercive force 110 to 14
0 Oe, saturation magnetization 55-65 emu / g, residual magnetization 10
Spherical polyhedral crystal with characteristics of 20 emu / g
Is desirable. If the average particle size is 0.50 μm or more,
Is likely to be non-uniform, which is not preferable. Coercive force, residual
If the magnetization is small, the magnetic field of the magnetic drum
It is preferable because the direction of the magnetic pole changes and fogging occurs
Is small, the toner transportability is small if the saturation magnetization is small.
You. Also, if needle-like magnetic powder is used, coercive force, remanence
The image becomes large and full, but the fixability decreases.
Is not preferred. The proportion of the magnetic powder in the magnetic latent image developing toner of the present invention is preferably in the range of 50 to 70 parts by weight. If the proportion of the magnetic powder is less than 50 parts by weight, the magnetic force of the toner is weakened, the transportability of the toner is reduced, 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 undesirably reduced.

Further, since the magnetic head performs recording while slightly floating on the surface of the magnetic recording medium, if the amount of triboelectric charge of the toner is large, the toner adheres to the magnetic head and the floating becomes unstable, Therefore, the distance between the magnetic recording medium and the magnetic head becomes uneven, and the image quality deteriorates. In order to prevent this, the amount of triboelectric charge of the toner for developing a magnetic latent image is preferably set in the range of -5 to 5 C / g.

As a method for controlling this, there is a method using an external additive and a charge control agent. For example, by adding hydrophobic silica, aluminum oxide, or titanium oxide as an external additive, the triboelectric charge can be controlled in the range of -5 to 5 C / g. Further, it is clear that the same result can be obtained even when a plurality of external additives are used.

Commercial products that can be used as external additives include
Nippon Aerosil Co., Ltd. product name "RA200H" and Wacker Chemicals East Asia Co., Ltd. product name "HD
KH2050EP "," HDKH2015EP "and the like, and as the aluminum oxide, Nippon Aerosil Co., Ltd.
There is a product name "RFY-C" manufactured by Nippon Aerosil Co., Ltd., and furthermore, a product name "T-805" manufactured by Nippon Aerosil Co., Ltd.
Etc. exist.

Further, -5 to 5 μC /
It can also be controlled within the range of g (see JP-A-3-210568). As the charge control agent, Nigg <br/> reactor core is Application Benefits triphenylmethane dyes can be used.

Commercially available charge control agents include, for example, "Bontron N-01" (trade name) manufactured by Orient Chemical Co., Ltd.
Examples include "Bontron N-04" and a product name "Copy Blue PR" manufactured by Hoechst Japan K.K. Thus, the charge amount of the toner can be controlled by the external additive and the charge control agent. In the present invention, a wax can be contained for improving the offset and the fixing property.

As the wax which can be used in the present invention, a polyolefin wax such as a polyethylene wax or a polypropylene wax can be used. As the polyethylene wax, “Hi Wax NL-500” (softening point 110 ° C.) manufactured by Mitsui Petrochemical Industry Co., Ltd. can be used, and as the polypropylene wax, “Hi Wax” manufactured by Mitsui Petrochemical Industry Co., Ltd. NP055 "(softening point: 136 ° C) can be used. As the colorant, carbon black and other dyes and pigments can be used, and can also serve as an electric resistance adjuster.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples. Example 1 KBF-100S (trade name) 250 parts by weight (triiron tetroxide manufactured by Kanto Denka Kogyo Co., Ltd.) (average particle size 0.20 μm, Hc = 115 Oe, σs = 58.8 emu / g, σr = 11.4) emu / g) FC-051 (trade name) 120 parts by weight (Mitsubishi Rayon polyester resin) FC-344 (trade name) 20 parts by weight (Mitsubishi rayon polyester resin) Leorex AS-170 (trade name) 8 parts by weight (A quaternary ammonium base-containing copolymer manufactured by Daiichi Kogyo Seiyaku) High Wax NL-500 (trade name) 10 parts by weight (Mitsui Petrochemical Industries polyethylene wax) Copy Blue PR (trade name) 3 parts by weight (Hoechst Industry Charge control agent) The above components were mixed, melt-kneaded, cooled to room temperature, coarsely pulverized, medium pulverized, then finely pulverized and classified by a jet mill, and the average particle size was 9 mm. Obtain a magnetic toner of Ron. This toner was externally mixed with 0.3 part by weight of “RFY-C” (aluminum oxide manufactured by Nippon Aerosil Co., Ltd.) to obtain a toner for developing a magnetic latent image of Example 1. The amount of triboelectric charge is-
0.9 μC / g and an electric resistance of 4.2 × 10
It was ¹¹ Ωcm.

Comparative Example 1 A toner for developing a magnetic latent image of Comparative Example 1 was obtained in the same manner as in Example 1 except that the composition was not compounded with Leorex AS-170. The triboelectric charge was -2.0 µC / g, and the electric resistance was 3.2 × 10 ¹⁴ Ωcm.

Example 2 KBF-100S (trade name) 250 parts by weight (iron trioxide manufactured by Kanto Denka Kogyo) (average particle size 0.20 μm, Hc = 115 Oe, σs = 58.8 emu / g, σr = 11.4 emu / g) FC-051 (trade name) 120 parts by weight (polyester resin manufactured by Mitsubishi Rayon) FC-344 (trade name) 20 parts by weight (polyester resin manufactured by Mitsubishi Rayon) Leorex AS-170 (trade name) 30 parts by weight (Daiichi Kogyo Seiyaku Co., Ltd. quaternary ammonium base-containing copolymer) High Wax NL-500 (trade name) 10 parts by weight (Mitsui Petrochemical Industries polyethylene wax) Copy Blue PR (trade name) 3 parts by weight (Charge Control Agent Made by Hoechst Industry) A toner for developing a magnetic latent image of Example 2 was obtained in the same manner as in Example 1 except that the above components were used. At this time, the triboelectric charge was +0.8 μC / g, and the electric resistance was 7.3 × 10 ⁸ Ωcm.

Comparative Example 2 KBF-100S (trade name) 250 parts by weight (iron trioxide, manufactured by Kanto Denka Kogyo Co., Ltd.) (average particle size 0.20 μm, Hc = 115 Oe, σs = 58.8 emu / g, σr = 11.4 emu / g) FC-051 (trade name) 120 parts by weight (Mitsubishi Rayon polyester resin) FC-344 (trade name) 20 parts by weight (Mitsubishi Rayon polyester resin) Carbon black # 3250 (trade name) 15 Parts by weight (Mitsubishi Kasei's conductive carbon black) High Wax NL-500 (trade name) 10 parts by weight (Mitsui Petrochemical Industries polyethylene wax) Copy Blue PR (trade name) 3 parts by weight (Hoechst Industry's charge control agent) A toner for developing a magnetic latent image of Comparative Example 2 was obtained in the same manner as in Example 1 except that the above components were used. The triboelectric charge was -1.2 [mu] C / g, and the electric resistance was 8.3 * 10 < ⁸ > [Omega] cm.

Next, MG-8 manufactured by Iwasaki Communication Equipment Co., Ltd.
Using a 100-type printer, image output was performed on the magnetic latent image developing toner obtained in each of the above Examples and Comparative Examples. 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) Amount of triboelectric charge 100 parts by weight of surface iron oxide powder (TEFV manufactured by Powdertech) having a particle size of 200 to 300 mesh and 3 parts by weight of each toner for developing a magnetic latent image are put in a 100 ml glass container. The mixture was mixed for minutes, and measured with a blow-off charge amount measuring device manufactured by Toshiba Chemical Corporation. 3) Head Staining One copy per record was repeated 5000 times using an MG-8100 type printer manufactured by Iwasaki Communication Equipment Co., Ltd., and the adhesion of toner to the magnetic head at that time was evaluated. ○ There is no head dirt, or there is very little dirt. △ The toner adheres to the head. C: The toner adheres to the head, and the image becomes faint during recording.

4) Electric Resistance The toner for developing a magnetic latent image is molded under a pressure of 3 ton / cm ^{2 so} as to have a diameter of 5 cm and a thickness of 5.0 mm.
It was measured at a voltage of V. 5) Sharpness of characters ○ There is no toner scattering or very slight scattering around characters. △ Toner scattering around characters. × The toner is very scattered around the character, and the character appears blurred. 6) Fixing ratio The reflection density of the printed 1 × 1 cm solid was measured. Thereafter, a cellophane tape was attached and pressed at a pressure of 10 kg / cm, and then 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
(%).

[0025]

[Table 1]

As is clear from Table 1, the toner containing the quaternary ammonium salt group-containing copolymer can provide a good image without changing the reflection density and the sharpness of characters depending on the type of paper. In addition, the toner for developing a magnetic latent image obtained in each of the examples does not increase the character dust and fog even after repeated copying, and a good image is obtained, and sufficient fixability is obtained.

[0027]

According to the present invention, it is possible to provide a stable and good image with good image quality, sufficient fixability even at high speed printing, good storage stability and no head contamination.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-124731 (JP, A) JP-A-59-170848 (JP, A) JP-A-58-95752 (JP, A) 210568 (JP, A) JP-A-4-151166 (JP, A) JP-A-54-32328 (JP, A) JP-A-2-7071 (JP, A) JP-A-3-282482 (JP, A) JP-A-4-198308 (JP, A) JP-A-6-271780 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/08 G03G 9/083 G03G 9/087 G03G 9/097

Claims (2)

(57) [Claims] 1. A binder resin as a main component, an average particle diameter of 0.20 to 0.45 μm, a coercive force of 110 to 140 Oe,
Saturation magnetization 55-65 emu / g, residual magnetization 10-20 emu
/ G of magnetic powder containing 50 to 70% by weight of a magnetic powder containing 1 to 8 parts by weight of a quaternary ammonium salt group-containing copolymer having the following general formula: Is in the range of 10 ⁸ to 10 ¹² Ωcm. Embedded image Here, R ₁ is H or CH ₃ , and R ₂ , R ₃ and R ₄ are 1 to
X represents CH ₃ O, a lower alkyl group having 4 carbon atoms.
SO ₃ and C ₂ H ₅ OSO ₃ , and n represents an integer of 2 to 4. 2. It contains an external additive and / or a charge control agent,
2. The toner for developing a magnetic latent image according to claim 1, wherein the toner has a triboelectric charge amount in a range of -5 to 5 [mu] C / g and an average particle diameter of 8 to 10 [mu] m.