JPS59191069A - Electrophotographic toner - Google Patents

Abstract

PURPOSE:To prevent agglomeration, to maintain a stable state, and to enhance fixability by incorporating an acicular substance in toner particles. CONSTITUTION:An acicular substance of about 0.7mum length, such as acicular magnetic powder, ceramics, org. and inorg. crystals, is added and dispersed into an ordinary toner of about 10mum average particle diameter. The acicular substance partially protrudes out of the surface of each toner particle thus produced, and these protrusions play the role of joints between the toner particles themselves or between the particles and transfer paper. When the toner particles attached to the paper are passed between fixing rollers, they are deformed by application of prescribed pressure or heat, and the protrusions of their surfaces intrude into the other toner particles and the fibers of the paper to enhance fixability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electrophotographic toner suitable for obtaining good fixing properties in a fixing process of an electronic copying machine or the like.

[Technical background of the invention and its problems]

There are heat fixing methods and pressure fixing methods that have been put into practical use as fixing methods for electronic copying machines and the like.

Among these, the heat fixing method is widely used because it is easier to obtain good fixing performance compared to the pressure fixing method, but in recent years, electronic copying machines have become smaller and lighter.
There is also a tendency for pressure fixing methods to be used for the purpose of reducing power consumption.

In the pressure fixing method, a predetermined pressure (approximately 25 (1 to 400
kg/cm) k In addition, the fixing property is determined by the deformation of the toner used under the above pressure, the adhesion and cohesiveness of the toners, and the better the adhesion to the paper, the better the fixing property is. Get better. On the other hand, as toner has these properties, toner tends to aggregate in mechanically stressed parts of the main body of electronic copying machines, such as the developing device or the blade IJ part, which can have a negative impact on images. Therefore, there is a limit to how good the fixing performance can be.

On the other hand, the heat fixing method heats and fuses the toner that is attached to the transfer paper, and compared to the pressure fixing method, the toner is It is a part that is subjected to mechanical stress, and the degree of convergence is small.

However, even in this heat fixing method, there are significant restrictions on the selection of toner materials in order to obtain good fixing properties. In addition, to improve the fixing performance of pressure fixing and heat fixing methods, toner with high cohesiveness is generally used, and even at room temperature, a considerable amount of toner aggregates in areas that are subject to mechanical stress, resulting in image formation. tends to have a negative impact on

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances.
A stable state is maintained without any doubts, and
The purpose of the present invention is to provide a complete toner for electrophotography that can improve fixing properties.

[Summary of the invention]

The present invention achieves the above object by incorporating a needle-like substance of a predetermined length into toner particles to produce toner particles having protrusions.

[Embodiments of the invention]

Next, the present invention will be explained in detail.

Generally known electrophotographic toners are produced by dispersing constituents (C pigment, dye, auxiliary agent, etc.) in a resin as a main component.

The toner of the present invention is obtained by further adding and dispersing needle-like substances to the above-mentioned known toner. The substance is contained. On the surface of the thus produced white toner, a needle T1 partially protrudes 1-1. This protrusion serves as a joint between the toner and the transfer paper during the adhesion process of an electronic copying machine or the like. In other words, the toner of the present invention is used in an electronic copying machine or the like, and the transfer paper on which the toner image is transferred is immediately applied to, for example, a pressure roller in the case of a pressure fixing method, or to, for example, a heat roller in the case of a heat fixing method. 'F1. Then, the toner adhered to the transfer paper is deformed by applying a predetermined pressure or pressure and heat, and the protrusions on the surface thereof become embedded in other toner and the fibers of the transfer paper. Therefore, the bonding force between the toner particles and between the toner particles and the transfer paper after fixing is strengthened, and thus the fixing performance is improved.

In other words, the toner in the present invention is a particle having a protrusion on its surface that serves as the joint. Therefore, the acicular substance contained in the toner particles in order to form the protrusions on the toner particle surfaces must have a predetermined length relative to the average particle diameter of the toner particles. It is desirable that the length of the needle-like substance is 5 to 20 inches relative to the toner particle diameter; if it is shorter than this, it will not be able to function as an effective joint, and if it is longer, Inconveniences arise, such as the toner not being able to perform its function satisfactorily. 1
Examples of materials used for needle-shaped materials include magnetic powder, ceramic ceramics, and needle-shaped organic and inorganic crystals.

The acicular substance is appropriately selected from among these materials, taking into consideration what kind of properties are required of the toner to be produced.

For example, when the toner to be produced is a magnetic toner, magnetic powder of acicular crystals is used as the acicular substance. In this way, a magnetic toner with excellent fixing properties can be obtained without using gelatinous raw powder in addition to needle-like substances. However, if the compatibility of the feather material selected as the acicular material with the resin used in the toner is too good, the acicular material may protrude from the surface of the toner particles when the toner is crushed in the toner manufacturing process. Therefore, it is necessary to take this point into consideration when selecting the material for the needle-like substance. Specific examples will be described below.

Examples Polyethylene wax BARECO100O (manufactured by Pedrydo) 35wt ethylene vinyl acetate copolymer 212 (manufactured by Mitsui Polychemicals) 5 wt % Carbon MA-100 (manufactured by Mitsubishi Kasei) 5
W is a magnetic powder containing 55 wt % of needle-shaped crystals having an average length of 1 μm and the above composition is thoroughly mixed in a lamixer, and this mixture is kneaded in a pressure kneader at about 1000° C. to 160° C. for 15 to 60 minutes. The resulting mixture was reduced to about 1
The toner of the present invention having an average particle size of 12 μm is produced by coarsely pulverizing the toner into particles of 1.0 mm or less, and then passing the resulting particles through a pulverization classifier. - As a comparative example of the Shiki example, magnetic powder BL-100 (manufactured by Toda Kogyo Co., Ltd.) was used instead of the above needle-like crystals.
A known magnetic toner having an average particle size of 12 μm was completely produced by using 55 wt % and mixing, mixing, coarsely pulverizing, and finely pulverizing classification I- under the same conditions.

FIG. 1 shows the results of comparison of fixing properties between this example and a comparative example. In other words, the same electronic copying machine (300kf
/cm2 pressure fixing device) with different density halftone patches (2CrlX2cr
After all the copying operations in step (n) were carried out, the resulting copied image was rubbed with paper using a commercially available friction tester, and the concentration of toner adhering to the paper was measured. As shown in the figure, in this example, the density of toner adhering to paper when rubbed with paper is lower than in the comparative example, and the fixing performance is improved.

In addition, in this example, as mentioned above, the magnetic powder of needle-shaped crystals is included in the above composition, which improves the fixing property. Furthermore, there is no need to include a material f4 in the above composition that would increase the cohesiveness of the toner, and direct contact with the toner is prevented by the protruding portions of the needle-like crystals. For this reason, the toner in this example maintains a stable state without agglomerating in the parts of the electronic copying machine where mechanical stress is applied, and therefore, an image of excellent image quality can be obtained on transfer paper, etc. in a good fixing state. be able to.

In addition, in this example, for toner with an average particle size of 12 μm,
, which uses needle-like crystals with a length of 1 μm, but for toner with an average particle size of 8 μm to 15 μm, the average particle size is 12 μm and the length is 0 μm.
．． Desired results were similarly obtained using needle-shaped crystals of 5 μm to 2 μm. Also, the one shown in Figure 1 is a comparison of the fixing properties of this example and a comparative example using the pressure fixing method. As a result, even in the heat fixing method using a heat roller or the like as described above, the protrusions on the surface of the toner particles made of acicular substances play the role of joints, and the fixing performance is improved.

Furthermore, the present invention is not limited to the present embodiment, and is not limited to i-i.
Various modifications are possible without changing the gist.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an electrophotographic toner that can withstand mechanical stress within the main body of an electronic copying machine or the like.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a comparison result of fixing properties between an example of the present invention and a comparative example. Agent Patent attorney Kensuke Chika (and 1 other person) Part 1 Fig. 58-6!T) 2!Oi 2, Title of invention for electrophotography [・Su- 3, Relationship with the case in which the amendment is made Patent applicant (307) Tokyo Shibaura Electric Co., Ltd.?-1,1 Agent Person 〒100 Tokyo = ``1-1-G Uchisaiwai-cho, Daita-ku, Tokyo Shibaura Electric Co., Ltd.'' Inside the office tlY1 6.1 Contents of the detailed description of the invention specified (1) ``Heat-fixing method'' on page 2, line 2 has been corrected to ``heat-fixing method.''
A3" and line 19] and 20i-i1" r Iiu Collection". (3) Similarly, page 3, line 4 [Heating Correct it to "r!11 Heat-C". (/4) Similarly, page 3, lines 7, 12, and 14.
i: fl, and the 19th line is corrected to ``1 'coagulation' is 7 agglomeration.'' (5) Similarly, in the 5th true 51i, it is corrected and reversed as ``When I am sent.'' (6) Similarly, at the beginning of line 11 of 58'A, ``l = then j is [and corrected as ill J.'' (7) Similarly, page 6, line 20 [1~〒page 7, first [do]
~Kan△ Sou” is corrected. (8) Similarly, page 8, line 13 and line 1811 [Corrected ``aggregation 1'' to ``aggregation.'' (9) Correctly, the 9th self, 18th tj [l r agglomeration j is corrected to ``aggregation''. 10

Claims (1)

[Scope of Claims] (1) An electrophotographic toner 0 (2) containing an acicular substance in the particles, and partially having protrusions made of the acicular substance on the surface of the particles. 2.) The electrophotographic toner according to claim 1, wherein the needle-like substance has an average length of 5% to 20 inches of the particle diameter. (3) The acicular substance is acicular solid powder having an average length of 0.5 μm, and is contained in particles with an average particle size of 8 μm to 15 μm. 2
Electrophotographic toner described in section