JPH0731414B2 - Toner for pressure fixing - Google Patents

Description

The present invention relates to a pressure fixing toner used in electrophotography, electrostatic recording, magnetic recording, electrostatic printing or the like.

Conventionally, a so-called "fixing" operation is performed when an electrostatic latent image, a magnetic latent image, or the like is developed with a colored powder called toner, and then the image is desired to be stored. As such a fixing method, a method of melting the toner in a heat chamber and adhering the latent image-bearing surface as it is or after transferring it to a transfer body, a method of melting the toner with a heat roller and at the same time embedding the toner, and a solvent are used. Known methods include a method of removing the solvent after dissolving and adhering the toner, and a method of applying and fixing a resin solution called a fixing solution on the image.

However, such a fixing method which has hitherto been known has a serious weak point. That is, all of these fixing methods require time for fixing. That is, in order to actually fix the image, it takes time for the toner to melt, the time for melting, the time for evaporation of the solvent, etc. Such a time is not a problem when it is desired to fix only one image, but it is a serious obstacle when it is desired to fix a large number of images continuously. Needless to say, the fixing method using a solvent or a liquid is disadvantageous, but other fixing methods are difficult to answer the request for fixing at a higher speed because there is an operation of melting with heat. . When heat is used, flash exposure, infrared exposure, induction heating, or a combination of them is used to more effectively use the heat. However, there is essentially a limit to increasing the efficiency, and since the required amount of heat is the same for each sheet, there is no choice but to supply a larger amount of heat when fixing at a higher speed. As the technology has advanced recently and information needs to be diversified and speeded up, and image information needs to be transmitted at high speed, this fixing time for storing image information needs to be extremely short. Therefore, the actual situation is that a fixing device having a larger heat source is used accordingly.

A fixing method, which is so-called a pressure fixing method, which fixes an image only by pressure, is a fixing method that has been recently receiving attention as compared with the conventionally known fixing method. Since this method can fix the toner only by pressure, there is a merit that an operation of giving heat is not necessary as compared with the other methods described above, but a larger merit is that “the fixing does not take time”. That is, pressure fusing occurs instantaneously as the image passes through the pressure roller. The only condition for pressure fixing is to apply pressure, and it does not take time like melt evaporation. It is natural to think that the pressure fixing method is the most promising as a means for higher speed fixing.

However, the conventionally known pressure fixing method has the above-mentioned great merits, but has some serious drawbacks. One of them is that the pressure for fixing is generally 20-40kg / c.
Although the linear pressure is m, the strength of the fixing device is required to be fairly strong in order to apply such a force, which is not preferable because the fixing device becomes large and heavy. The other one
First, it is extremely and essentially difficult to apply the above pressure uniformly to an image such as a transfer paper, and it is extremely difficult to prevent the transfer paper from wrinkling or curling. . Furthermore, when the above-mentioned pressure is applied to the image by the roller, the image surface is smoothed, the image becomes glossy, and the image quality is deteriorated. Further, since the fixing property of pressure fixing greatly changes depending on the linear pressure at the time of fixing and the property of the fixing base, for example, even if the width of the paper is changed or the transfer paper is changed, the fixing property is changed even in the same fixing device. In some cases, this is also a serious drawback that causes practical problems. In reality, some kind of ingenuity is trying to get rid of these problems, and it is actually put to practical use. For example, the fixing roller may be matted for matting, or the rollers may have a crossing angle for even pressure. However, even if these methods are used, for example, the matting roller itself eventually becomes a smooth roller due to a large fixing pressure, or the crossing angle causes wrinkling to occur. The problem will arise again.

Seen in this way, the above problem is an essential problem associated with pressure fixation, and it seems that there is no means for solving it. In fact, it is difficult to get rid of these problems with the above-mentioned measures.

An object of the present invention is to provide a pressure-regulating toner having excellent developability and pressure fixing property. Another object of the present invention is to provide a pressure fixing toner which is less affected by a change in fixing speed and which is particularly suitable for light speed fixing. Another object of the present invention is to provide a pressure-fixing toner which is less affected by a change in fixing pressure and which can be fixed even at a low pressure. Another object of the present invention is to provide a pressure-fixing toner in which the fixing property is less likely to change due to the difference in the fixing base.

Specifically, the present invention is a hydrocarbon wax having a softening point of 90 ° C or higher and a molten clay at 130 ° C of 6 to 100 cps (excluding styrene-based graft polyethylene wax).
The present invention relates to a pressure-fixing toner, characterized by containing as a binding substance.

The hydrocarbon wax used in the present invention is a wax whose constituent elements of the molecule are substantially composed of carbon and hydrogen.

Such a hydrocarbon wax is preferably contained in the binder in an amount of 3 to 100% by weight (more preferably 10 to 100% by weight).

The present inventors have studied various materials for pressure fixing. As a result, it has been found that the use of the above-mentioned materials significantly improves the characteristics of the pressure fixing toner. Various materials are conventionally known for manufacturing pressure fixing toner. Various natural and synthetic waxes are known as the most common materials. In particular, materials have been selected for the purpose of fixing a toner with a light pressure, and for example, a light pressure fixing toner using a combination of a polymer substance and wax is also known. These toners were toners that were fixed at a pressure much lower than that of conventional pressure fixing toners. However, when trying to carry out light pressure fixing in the combination of these materials, there were some problems. One was mechanical strength, and the other was pigment dispersibility. The present inventors have continued to study in this respect, and have found that the use of the material according to the present invention described above provides a great effect on the above problems.

The hydrocarbon wax used in the present invention has a higher clay content than that known as a conventional pressure-fixing toner wax, and is lower than the conventional polyethylene wax for a pressure-fixing toner. It is of clay.

Hydrocarbon waxes suitable for the present invention include paraffin wax, isoparaffin wax and polyethylene wax, which are commercially available under the following trade names.

These materials may be used alone or because they have pressure fixing properties, but when used in combination with various conventionally known pressure fixing materials, the amount of the above materials may be 5% by weight or more. is necessary.

Pressure fixing materials that can be used in combination include those marketed as low molecular weight polyethylene or polyethylene wax, Hoechst AG, Celanese Plasti
cs, Philips Petroleum Co, National Petrochemi cals C
orp, Union Carbide Corp., British Hydrocarbon Chemic
It is manufactured and sold by als, Ltd., Furukawa Chemical, Mitsui Petrochemical, Showa Denko, Chitso, etc. Alternatively, the conventionally known pressure-fixing wax is a long-chain compound having a C _{12 to} C ₅₀ carbon chain, which is a C _{12 to} C ₅₀ hydrocarbon, a fatty acid, and an ester thereof, a metal soap, and a fatty acid. They are alcohols, polyhydric alcohols, their metal salts and their chlorides, fluorides, amides, and bisamides. Commercially available products include Paraffin wax, microcrystalline wax, and amido wax. Manufacturers and trade names include Paraffin Wax (Nippon Petroleum), Paraffin Wax (Nippon Seiwa), Microwax (Nippon Petroleum), Microcrystalline Wax (Nippon Seiwa), Hoechst Wax (hoecst AG),
Diamond Wax (New Japan Rika), Suntite (Seiko Chemical), Panacet (Nippon Yushi) and others.

Further, as the binder resin of the toner of the present invention, another known resin may be mixed in addition to the pressure fixing material. For example, polyester resin, epoxy resin, silicone resin, polystyrene, polyamide resin, polyurethane resin, acrylic resin, etc., but the amount thereof should not exceed 30% by weight of the whole binder resin.

As the coloring material used in the toner of the present invention, all known materials can be used, and examples thereof include carbon black, iron black,
Examples include nigrosine, benzidine yellow, quinacridone, rhodamine B, and phthalocyanine blue.

In order to use the toner of the present invention as a magnetic toner,
Magnetic powder may be included. As such magnetic powder, a substance that is magnetized when placed in a magnetic field is used.
There are powders of ferromagnetic metals such as cobalt and nickel, and compounds such as magnetite, hematite, and ferrite. The content of the magnetic powder is 15 to 70% by weight based on the weight of the toner.

Additives may be added to the toner of the present invention for various purposes. Examples of such additives include metal complexes, charge control agents such as nigrosine, lubricious compounds such as polytetrafluoroethylene, and plasticizers such as dicyclohexyl phthalate. Further, for the purpose of improving the free flowing property of the powder, it is possible to use it by mixing it with a hydrophobic colloidal silica fine powder or an abrasive fine particle such as cerium oxide for preventing toner sticking.

The toner of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder and ferrite powder, if necessary, and used as a developer for an electric latent image.

The first characteristic of the pressure-fixing toner thus configured is that it fixes even at a low pressure.
Fixes at a pressure of ~ 1/5. There are also some practically important properties. One of them is that there is little dependence on the fixing device. Conventionally, in order to perform pressure fixing, it was necessary to locally apply strong pressure with a contact area as small as possible, so a rigid roller is used. Therefore, it is difficult to obtain the stability and strength of the member for holding it practically, and there are cases where the device becomes large and durability becomes a problem. However, the pressure-fixing toner according to the present invention itself exhibits strong self-aggregating property, and therefore, fixing can be performed without a strong local force. Therefore, for example, a pressure roller having some elasticity can be put to practical use.

Further, a greater advantage of the pressure-fixing toner of the present invention is that the surface to be fixed has very low selectivity. It has been well known that pressure fixability varies greatly depending on the surface to be fixed. However, in practice, it is also preferable that it has the same fixing property on any surface, and the present invention enables complete PPC pressure fixing, which has heretofore been impossible with the pressure fixing component.

Another characteristic of the pressure-fixing toner of the present invention is that the fixing force has little dependency on the fixing speed. As described above, the pressure fixing has been a fixing method having less speed dependency than the conventional heat fixing. However, the use of the conventional pressure-fixing component cannot eliminate the speed dependence at all, and requires a little additional pressure for high-speed fixing. However, when the toner according to the present invention is used, there is absolutely no dependency on the fixing speed, and in the experiments conducted by the present inventors, the same fixing property was obtained from 50 mm / sec to 500 mm / sec.

Further, the feature of the toner of the present invention is that its fixing is less dependent on pressure. Since the pressure fixing is fixed by the pressure, it naturally has pressure dependency, and the conventional toner has a large change in the fixing force with respect to the pressure. However, the same pressure is not always applied to the pressure fixing device, for example, when the paper size changes, the fixing pressure also changes, and it is also possible to intentionally change the pressure, for example, to prevent wrinkles. Done. When a conventional toner is used for such a system, there arises a problem that the fixing property is different depending on the part of the paper. However, since the toner according to the present invention has little pressure dependency of the fixing force, such a phenomenon does not occur.

Furthermore, a very important feature of the binder resin composition of the present invention is that the effect of inhibiting fixing is small even when the composition is combined with other non-fixing components.

When conventional pressure-fixing components are used, pigments, charge-imparting agents, and anti-blocking agents may be added as needed, but in such cases, even if a small amount of such non-fixing components is included, fixing is extremely difficult. It is a characteristic of the conventional composition that the property is lowered. However, the binder resin composition of the present invention has very little of these effects, and can be used without worrying about the fixing property by mixing various additives and processing agents as needed. This shows that the binder resin composition of the present invention is not only used as it is as a pressure-fixing material, but also extremely useful as a core material when encapsulated, for example. Is.

The basic structure and features of the present invention have been described above, but the method of the present invention will be specifically described below based on Examples.

[Example 1] Isoparaffin wax (molten clay at a softening point of 117 ° C and 130 ° C, 20 cps; Neowax L manufactured by Yasuhara Yushi Co., Ltd.) 100 parts by weight Phthalocyanine blue 10 parts by weight After the above mixture was melted by heating and mixed well, about 120 ° C
The mixture was kneaded with a three-roll heated to. After allowing the kneaded product to cool naturally,
It coarsely pulverized with a cutter mill and pulverized with a fine pulverizer using a jet air flow. This was classified using an air classifier to obtain pressure fixing toner fine particles having a diameter of 10 to 20 μm.

This toner was applied to a developing device having a sleeve to develop a latent image having a positive electrostatic charge, and then transferred to a fine paper.
A transfer paper with an image was passed through a pressure fixing device consisting of two pressure rollers that were able to apply pressure from both ends, and a nearly perfect fixing property was achieved at a line pressure of 15 kg / cm at a speed of 125 mm / sec. showed that. The development density was as good as 1.5.

Further, similar fixing tests were conducted at speeds of 2 times and 3 times, but the fixing properties were not changed at all. Moreover, the paper quality was changed, but the change in fixing property due to the paper quality was extremely small.

Further, when continuous copying was performed by replenishing the toner, an image having no change was obtained even after 3,000 copies were continuously printed.

[Comparative Example 1] For pressure fixing in the same manner as in Example 1 except that polyethylene wax (melting point: 123 cp, molten clay 180 cps at 130 ° C., PE130 manufactured by Hoechst) is used instead of the in-paraffin wax. A toner was prepared. An image was formed in the same manner as in Example 1, and the toner image was pressure-fixed. When the linear pressure was 15 kg / cm, the toner of Comparative Example 1 had a weaker fixing force than the toner of Example 1, and the fixed image was fixed. It was easy to peel off. When the line pressure was raised to 40 kg / cm and it was fixed,
A good fixed image was obtained, but the fixing speed was 250 mm / sec.
As a result, the fixing property of the toner deteriorated.

[Comparative Example 2] Paraffin wax # 140 (molten clay at a softening point of 60 ° C and 130 ° C, about Icps, manufactured by Nippon Seiro Co., Ltd.) was used in the same manner as in Example 1 except that isoparaffin wax was used. A fixing toner was prepared. Images were printed out in the same manner as in Example 1, and the toner images were pressure-fixed. The toner images showed good fixability, but the image density was 0.8.
Was lower than that of Example 1. Further, when continuous copying was performed, the image density was further reduced after several tens of copies.

[Example 2] AC polyethylene # 6 5 parts by weight Polyethylene wax (molten clay at a softening point of 120 ° C and 130 ° C 20 cps; Mitsui Petrochemical high wax (Hi-WAX) 100p) 10 parts by weight Paraffin wax # 155 85 parts by weight 60 parts by weight of magnetite After mixing the above materials well with a blender,
Knead well with this roll. The kneaded product was pulverized in the same manner as in Example 1 to obtain a toner.

The obtained toner was applied to a developing device having a magnetic sleeve to develop a latent image having a positive electrostatic charge, and then transferred to high quality paper. A transfer paper bearing an image was passed through a pressure fixing device consisting of two pressure rollers that were able to apply pressure force from both ends, and a nearly perfect fixing property was achieved at a speed of 200 mm / sec and a linear pressure of 9 kg / cm. showed that. The development density was as good as 1.5. Also, it is possible to replenish the toner continuously 20
After continuous copying of 00 sheets, an image with no change was obtained.

[Example 3] Paraffin wax (molten clay at a softening point of 99 ° C. and 130 ° C. 10 cps; Japanese wax Luvax (LUVAX) -1151) 15 parts by weight Paraffin wax 155 85 parts by weight Quinacridone red pigment 5 parts by weight After mixing and melting, the dispersion material was dispersed in the dispersed hot water. Then cool, wash and dry to a diameter of approximately 10
Spherical particles of μm were obtained. The particles were microcoated by a spray dry method to obtain a microcapsule toner.

This toner was used for development, transferred, and then passed through a metal pressure roller with a linear pressure of 10 kg, whereupon it was completely fixed at a speed of 100 mm / sec. The image did not change even after continuous copying.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Wakamiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-56-5559 (JP, A) JP-A-58 -215660 (JP, A) JP-A-58-63947 (JP, A) JP-A-58-108256 (JP, A)

Claims (1)

[Claims] 1. A pressure fixing method, which comprises a hydrocarbon wax having a softening point of 90 ° C. or higher and a melt viscosity at 130 ° C. of 6 to 100 cps (excluding styrene-based graft polyethylene wax) as a binding substance. For toner.