JPH06332226A - Heat fixing type developing toner composition - Google Patents

Abstract

PURPOSE:To provide the heat fixing type developing toner compsn. which is excellent in all of low-temp. fixability, offset resistance and nonblockability by incorporating a specific thermotropic crystalline low-polymer compd. into the toner compsn. CONSTITUTION:This heat fixing type developing toner compsn. consists essentially of a binder resin and coloring agents and contains the thermotropic crystalline low-polymer compd. The transition point (Tc) of the thermotropic crystalline low-polymer compd. from its crystalline state to a liquid crystal state exists between the glass transition temp. and softening point of the binder resin. The thermotropic crystalline low-polymer compd. is not particularly limited, insofar as the Tc exists between the glass transition temp. and softening point of the binder resin. The representative thermotropic crystalline low-polymer compds. includes a Schiff compd. (azomethine compod.), azoxy compd., cyanibiphenyl compd., cyanophenyl compd., benzoate compd., etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner composition used for electrophotography and the like. More specifically, it is a toner composition for heat-fixing type developing used in a so-called dry developing method of developing an electrostatic image. It is about things.

[0002]

2. Description of the Related Art In a dry developing method, a toner is usually charged by friction with iron or glass beads called a carrier, which is attached to an electrostatic latent image on a photoreceptor by an electric attraction, and then on a paper. And is fixed by a heat roll or the like to form a permanent visible image. As a fixing method, a heating roller method is often used in which the surface of a heating roller formed of a material having releasability for toner is passed through the toner image of a fixing target sheet while being in pressure contact. There is. In this heating roller method, a resin that can be fixed at a lower temperature is required in order to improve economy such as power consumption and increase the copying speed.

On the other hand, when the roll temperature rises, a phenomenon (hot offset) in which the toner is fused to the roll appears. This hot offset temperature is desired to be high, and it is also necessary that it is non-blocking at a temperature of 60 ° C. or lower. In order to satisfy these three characteristics of low temperature fixing property, offset resistance and non-blocking property, a toner resin has conventionally been composed of a styrene-acrylic resin composed of a low molecular weight polymer component and a high molecular weight polymer component. A technique (Japanese Patent Laid-Open No. 56-158340, etc.) has been proposed, but a sufficiently low fixing temperature has not been obtained.

[0004]

The conventional binder resin for toner is in a state called a glass region below Tg (glass transition temperature) and is in a state in which it cannot flow. When it exceeds Tg, the resin becomes a region called a rubber-like region, and at the temperature of this region, polymer particles come to coalesce (blocking property). Next, at the softening point, the resin melts into a fluid state, but in order to enable fixing at a lower temperature, it is desired that the resin have a low flow initiation temperature and a low melt viscosity. However, if the melt viscosity is too low at high temperature, the offset resistance becomes poor.

In the hot roll fixing method, in order to perform high-speed fixing with low power consumption, it is effective to lower the softening point of the binder material of the toner and lower the melt viscosity. When the softening point of the polymer (binder material) is lowered, the fluidity is excessively lowered, that is, the melt viscosity is remarkably lowered, so that the offset resistance is lowered. In addition, the blocking property also deteriorates due to the decrease in Tg. That is, in order to achieve low-temperature fixing with a normal resin, the Tg and melt viscosity of the resin decrease, and it is very difficult to balance the blocking property and the offset resistance.

The object of the present invention is to provide a heat-fixing type toner having excellent low-temperature fixability, anti-offset property and non-blocking property, which were very difficult to balance with conventional resin compositions for toner. To provide a developing toner composition.

[0007]

The heat-fixing type developing toner composition of the present invention comprises a binder resin and a colorant as main components, and contains a thermotropic liquid crystal low molecular compound, and the thermotropic liquid crystal low molecular compound. Is characterized in that the transition point (Tc) from the crystalline state to the liquid crystal state exists between the glass transition temperature and the softening point temperature of the binder resin.

The thermotropic liquid crystal low molecular weight compound used in the present invention is not particularly limited as long as its Tc exists between the glass transition temperature and the softening point temperature of the binder resin. Generally, Tc is about 60 ° C. or higher,
The transition temperature (Ti) from the liquid crystal state to the isotropic state is 130.
It is preferably about 0 ° C or lower. Typical thermotropic liquid crystal low-molecular compounds include Schiff compounds (azomethine compounds), azoxy compounds, cyanobiphenyl compounds, cyanophenyl compounds, benzoic acid ester compounds,
Examples thereof include a cyclohexanecarboxylic acid phenyl ester compound, a cyanophenylcyclohexane compound, a cyano-substituted phenylpyridine compound, an alkoxy-substituted phenylpyrimidine compound, and a phenyldioxane compound.

The binder resin used in the present invention is not particularly limited, but for example, polystyrene,
Poly P-chlorostyrene, homopolymers of styrene such as polyvinyltoluene and its substitution products, styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers Polymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene- (methacrylic acid) ethyl copolymer, styrene-butyl methacrylate copolymer, styrene-d chloromethallyl Methyl acid copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene Styrene-based copolymers such as copolymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, styrene-maleic acid ester copolymers, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyacetic acid Vinyl, poly Ren, polypropylene, polyester, polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin may be used alone or in combination.

Further, in the present invention, it can be used in combination with various waxes such as carnauba wax, montan wax and paraffin wax. Further, polyethylene wax, polypropylene wax or the like can be used together as a release agent.

As the colorant used in the present invention, various pigments and magnetic materials can be used in addition to ordinary carbon black. In the present invention, the thermotropic liquid crystal low molecular weight compound can be added when kneading the binder resin, the colorant and the like with a heating double roll or the like, and when the binder resin is synthesized, the thermotropic liquid crystal low molecular weight compound can be added in advance. A molecular compound may be added.

In the present invention, the addition amount of the thermotropic liquid crystal low molecular weight compound is preferably the binder resin 1.
It is 1 to 50 parts by weight with respect to 00 parts by weight.

[0013]

[Function] The thermotropic liquid crystal low-molecular weight compound has a crystalline region, a liquid crystal region, an isotropic region (molten state) depending on the temperature.
It is known to take three different states. In a normal crystalline low-molecular compound, when the crystal structure is solved, it instantly becomes a low-viscosity molten state. Since it has properties, it exhibits a liquid crystal state in which it is in a fluid state but has an appropriate melt viscosity.
Further, when the liquid crystallinity is lost, the melted state has a low viscosity, which is an isotropic region in which the regularity of molecules is not completely maintained.

The present invention is such a thermotropic liquid crystal low molecular weight compound, wherein the transition point (Tc) from the crystalline state to the liquid crystal state exists between the glass transition point and the softening point temperature of the binder resin. Such a thermotropic liquid crystal low molecular compound is contained. Therefore, at a temperature lower than the softening point of the binder resin, the liquidity of the thermotropic liquid crystal low molecular weight compound allows the toner to flow as a whole, and the toner can be fixed in this state. Further, since the Tc of the thermotropic liquid crystal low molecular weight compound is higher than the glass transition temperature of the binder resin, the blocking property does not matter and the offset resistance does not matter either. Further, from the viewpoint of offset resistance, the transition temperature (Ti) from the liquid crystal state to the isotropic state is preferably near the softening point of the binder resin.

[0015]

Description of Examples Example 1 Styrene / n-butyl acrylate / 2-ethylhexyl acrylate copolymer (glass transition temperature = 60 ° C.,
Softening point temperature = 118 ° C.) ... 100 parts by weight 4-propyl-4′cyano-azomethine (compound shown in [Chemical Formula 1] below, Tc = 65.5 ° C., Ti = 77.6)
C.) 20 parts by weight Carbon black (trade name MA-100: manufactured by Mitsubishi Kasei Co., Ltd.) 5 parts by weight PP wax (trade name Viscole 660P: manufactured by Sanyo Kasei Co., Ltd.) 3 parts by weight

[0016]

[Chemical 1]

The mixture having the above composition was melt blended, cooled, coarsely pulverized, and then finely pulverized by a jet mill to obtain about 12
A toner powder was prepared having an average particle size of ~ 15 microns. Hydrophobic silica powder (trade name R-9
72: manufactured by Nippon Aerosil Co., Ltd.) 0.3 part by weight was added to prepare a toner.

After this toner was left in a constant temperature bath at 60 ° C. for 16 hours, the aggregation degree was measured with a powder tester (manufactured by Hosokawa Micron Co., Ltd.). As a result, no aggregation property (blocking property) was observed. Further, 4 parts by weight of this toner was mixed with 96 parts by weight of an iron carrier having an average particle size of about 50 to 80 microns to prepare a developer, and a copy was obtained using this developer. The electrophotographic copying machine used is a modified DC-5055 manufactured by Mita Kogyo Co., Ltd. The heat roller temperature was as low as 110 ° C., showing a sufficient degree of fixing, and the offset generation temperature was 160 ° C. or higher, which was sufficiently high.

Example 2 A toner and a developer were prepared in the same manner as in Example 1 except that the binder resin and the thermotropic liquid crystal low molecular weight compound were changed as follows. And evaluated. Styrene / n-butyl acrylate copolymer (glass transition temperature = 60 ° C., softening point temperature = 110 ° C.) ... 100 parts by weight Fluorine-based liquid crystal compound (compound represented by the following [Chemical Formula 2],
Tc = 76 ° C., Ti = 125 ° C.) ... 20 parts by weight

[0020]

[Chemical 2]

As a result, no blocking property was observed,
The heat roller temperature was as low as 115 ° C., and sufficient fixing degree was exhibited, and the offset generation temperature was 170 ° C. or higher, which was sufficiently high.

Comparative Example 1 Except that the liquid crystal compound was not added in Example 1,
A toner and a developer were prepared and evaluated in the same manner as in Example 1. As a result, no blocking property was observed and the offset temperature was as high as 200 ° C. or higher, but the fixing temperature was 150.
Since the temperature was ℃, it could not be fixed at a sufficiently low temperature.

Comparative Example 2 Except that no liquid crystal compound was added in Example 2,
A toner and a developer were prepared and evaluated in the same manner as in Example 2. As a result, no blocking property was observed and the offset temperature was as high as 190 ° C. or higher, but the fixing temperature was 1
The temperature was 45 ° C., and fixing was not possible at a sufficiently low temperature.

[0024]

INDUSTRIAL APPLICABILITY According to the present invention, by containing a thermotropic liquid crystal low molecular compound having Tc between the glass transition temperature and the softening point temperature of the binder resin, it is excellent in offset resistance and non-blocking property. And a toner composition that can be fixed at a lower temperature.

Claims (1)

[Claims] 1. In a heat-fixing type developing toner composition containing a binder resin and a colorant as main components, a transition point (Tc) from a crystalline state to a liquid crystal state has a glass transition temperature and a softening point of the binder resin. A heat-fixing type developing toner composition comprising a thermotropic crystalline low molecular weight compound which is present during a point temperature.