JPS6345100B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a toner used in electrophotography, printing technology, etc., and more particularly to a new pressure-fixable toner that can be fixed by pressure. Conventionally, as an electrophotographic method, U.S. Patent No. 2297691
Specification of No. 42-23910 and Special Publication No. 1973
Many methods are known, as described in Japanese Patent No. 24748, etc., but in general, a photoconductive substance is used to form an electrical latent image on a photoreceptor by various means, and then the Develop the latent image using toner,
After the toner image is transferred to a transfer material such as paper as necessary, it is fixed by heat, pressure, solvent vapor, etc. to obtain a copy. Various methods are also known for visualizing electrical latent images using toner. For example, the magnetic brush method described in U.S. Pat. No. 2,874,063, the cascade development method described in U.S. Pat. No. 2,618,552, the powder cloud method described in U.S. Pat. No. 2,221,776, and 42141
A large number of development methods are known, such as the jumping development method, the furbrush development method, and the liquid development method described in the patent specification. As toners used in these developing methods, fine powders in which dyes and pigments are dispersed in natural or synthetic resins have conventionally been used. Furthermore, it is also known to use fine developing powder to which a third substance is added for various purposes. For example, it is described in Japanese Patent Publication No. 16219/1983. The developed toner image is transferred and fixed onto a transfer material such as paper, if necessary. Methods for fixing toner images include heating and melting the toner using a heater or heated roller to fuse and solidify it to the support, softening or dissolving the binder resin of the toner with an organic solvent, and fixing it to the support, and applying pressure. A method of fixing toner on a support by using a method is known. The method of fixing toner by applying pressure is based on US Patent No.
It is described in specification No. 3269626, Japanese Patent Publication No. 46-15876, etc., and is energy saving, non-pollution, copying can be done without waiting time when the copier is turned on, there is no risk of burning copies, and high speed. It has many advantages such as being able to be fixed and having a simple fixing device. However, there are problems such as toner fixability and offset development to the pressure roller, and various research and development efforts are being carried out to improve the pressure fixability. For example, Japanese Patent Publication No. 44-9880 describes a pressure fixing toner containing an aliphatic component and a thermoplastic resin;
No. 52-108134 describes a capsule-type pressure fixing toner containing a soft material in the core, and JP-A-48-75033 describes a block copolymer of a tenacious polymer and a soft polymer. Pressure-fixed toners using coalescence have been described. However, it has sufficient pressure fixing performance, is easy to manufacture, does not cause offset phenomenon to the pressure roller, and has stable development performance and fixing performance even after repeated use. A practical pressure-fixable toner that does not adhere to the surface of a photoconductor, does not aggregate or form a cake during storage, and has good storage stability has not been obtained. Furthermore, recently, a method has been used in which electrostatic latent images are developed using a one-component developer that contains magnetic fine particles in the toner and does not use carrier powder, but in this case, the toner binding resin is magnetic. Dispersibility and adhesion with fine particles, impact resistance, and fluidity of the toner are required. During development by frictional charging between this one-component developer and the developing sleeve roller, the insulating material separates due to impact or use over time, adheres to the sleeve roller due to triboelectric action, and accumulates, making it extremely durable. One-component developers still have many problems, such as poor performance. These problems also occur in the pressure fixing of magnetic toner for developing magnetic latent images. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a pressure fixable toner that can suppress the offset phenomenon to a pressure roller as much as possible compared to pressure fixable toners of the prior art. Another object of the present invention is to provide a pressure-fixable toner that is prevented from adhering to the surface of a carrier metal sleeve photoreceptor, etc., and has stable repeatability. Yet another object of the present invention is to provide a pressure fixable toner that is inhibited from forming agglomerated cakes during storage. Yet another object of the present invention is to provide a pressure fixable toner having stable triboelectric charging properties. Yet another object of the present invention is to provide a pressure fixable toner that exhibits suppressed changes over time. Yet another object of the present invention is to provide a pressure fixable toner with extremely good image properties. Yet another object of the present invention is to provide a pressure fixable toner that enables good pressure fixing at a lower pressure than pressure fixable toners according to the prior art. Yet another object of the present invention is to provide a pressure fixable toner that is easy to manufacture. Yet another object of the present invention is to provide a pressure-fixable toner having sufficient impact resistance against the impact normally experienced by toners. These objects of the present invention are such that the number average molecular weight Mn is
2000 to 5000, the ratio of weight average molecular weight Mw to number average molecular weight Mw/Mn is at least 2.8 or more of the total enthalpy of melting of the polyolefin.
This is achieved by a toner containing a polyolefin in which 50% or more of the melting enthalpy is at 110°C or higher and at least 30% of the total melting enthalpy is at 120°C or higher. At present, not much knowledge is known about pressure fixing mechanisms. Therefore, it is no exaggeration to say that which substances exhibit pressure fixing properties depends to a large extent on experience. The studies conducted by the present inventors while arriving at the present invention are also not related to the fixing mechanism. As is clear from the fact that the inventors of the present invention have consistently talked about the above-mentioned objectives in the pressure fixing toner, most of the objectives have been to improve the developability. The present inventors have been conducting intensive studies on polyolefin, which is widely known as a pressure-fixing material, and have also addressed various problems caused in the development process, such as fusion, durability in use, agglomeration, caking, triboelectrification,
We sought more knowledge about changes over time and offset, which is a problem in the fixing process. Under these circumstances, it is anticipated that the stability of the toner's binder resin will be an extremely important factor when considering the influence of the toner's thermal properties on agglomeration, caking, fusion, offset, and triboelectric charging properties. I came to the conclusion. It is necessary that the physical properties of the binder resin hardly change after the toner is manufactured until it is fixed on a support such as paper. The stability of the binder resin largely depends on its structural factors. A resin with an unstable internal structure causes changes in its internal structure in response to changes in the atmosphere and use environment, and in some cases, the changed state becomes fixed inside. In view of these points, I have come to believe that the free energy of toner is deeply connected to these problems, and that it is essential to consider this. In order for the toner to behave stably during the development process and other processes, it is required that the change in internal free energy of the toner itself in each process is small. In particular, it is desirable that the internal free energy change mainly depends on other parts than the entropy change. This is because entropy is a structural energy factor. Toner behavior in the developing process is determined by various energy balances. For example, in a system in which charging is achieved by friction, the fact that this energy is transferred to a balance other than charging will affect the charging efficiency. In particular, it is easy to imagine that the accumulation of energy in the form of entropy will have a large effect on cohesion, fusion, and changes over time, but the second law of thermodynamics cannot avoid this direction. I'm discussing things. In considering changes in internal energy and internal entropy of toner, the present inventors used a differential scanning calorimeter (DSC) as a means for considering changes in internal energy based on an external heat source. As a result, the conclusion reached by the present inventors is that the higher or larger the melting temperature Tm and melting enthalpy △Hm, the smaller the entropy term T△S of the internal energy in the usage environment. As a result, it is expected that the stability as a toner, that is, the developability will be in a more favorable state. Free energy change△
F is the temperature change in the usage environment or atmosphere when △T is extremely small. Since △F=O (1), △F=△H+T△S=O (2) Therefore, T=-△H/△S ( 3) is derived. For the stability of the toner in the development process and other processes, it is desirable that the entropy term TΔS in the system is small, and it can be seen from equation (3) that ΔS is a constant ratio with respect to ΔH. This shows that the enthalpy of fusion ΔH near the operating temperature needs to be small. The present inventors conducted differential scanning calorimetry on commonly available polyolefins and polyolefins prototyped using the method described below.
50% or more must be above 110℃,
It has been found that even more preferably 30% or more should be at 120°C or higher. Furthermore, when we added 5 parts of carbon black (Regal 400R manufactured by Kayabot) to these toners using a conventional method and made a prototype toner, we investigated the characteristics especially in the developing process, and found that at least 50% of the total enthalpy of fusion was in the range of 110°C or higher. The polyolefin contained therein had extremely good image properties and excellent triboelectric stability. In addition, cohesion, caking, etc. have been significantly improved, making it possible to minimize changes in toner physical properties during storage. This toner is mixed with 30 to 60 micron reduced iron powder and placed in the developer of a commercially available plain paper copier (NP-5000, manufactured by Canon), and the agitation screw and sleeve are rotated for 24 hours to melt the toner into the sleeve, etc. The degree of adhesion was examined, but no fusion was found. Similarly, 80 parts of magnetite (EPT-500 manufactured by Toda Kogyo) was added to the above polyolefin, and a toner was prepared in the same manner.
Hydrophobic colloidal silica (manufactured by Aerosil, R-
972) added at 1.5% to the toner was placed in the developer of a commercially available plain paper copying machine (NP-200J, manufactured by Canon) and the sleeve was rotated for 24 hours, but no fusion was found. A summary of this experiment is presented in Table 1.

[Table] ◎ Best ○ Good △ Fair
× Not possible This study, which is an important part of the present invention by the present inventors, was conducted using a commonly available commercially produced polyolefin and a polyolefin prototyped by the present inventors in the laboratory. . A brief description of the polyethylene manufacturing method made by the present inventors will be given below. Commercial production of solid high molecular weight polyethylene has until recently been limited to high pressure processes such as those disclosed in US Pat. No. 2,153,553. In this U.S. patent, ethylene is heated to a pressure of over 500 atmospheres, usually 1000~
It has been shown that it can be polymerized at pressures of 2000 atmospheres to produce solid wax polymers. These high pressure polymerization processes produce polyethylene with a high degree of chain branching, and the polymer exhibits relatively low softening temperatures, low density, and relatively low crystallinity. It has recently been discovered that polyethylene can be produced by polymerizing ethylene at fairly low temperatures in the presence of certain catalysts. For example, in U.S. Pat. No. 2,691,647 it is shown that ethylene can be polymerized in the presence of a catalyst mixture consisting of oxides of chromium, molybdenum, tungsten, or uranium activated by supported alkali metals. is being used. Similarly, U.S. Pat. No. 2,699,457 discloses that polyethylene is a metal alkyl such as aluminum triethyl or ethyl aluminum chloride, or a metal alkyl halide, and
It has been shown that polymerization can occur in the presence of a catalyst mixture with a group 6b metal compound. It has also been reported that a unique type of polyethylene can be produced by polymerizing ethylene in the presence of a catalyst mixture consisting of a metal such as aluminum and titanium tetrahalide. The above-mentioned methods of producing polyethylene are characterized by the use of relatively low pressures. Polyethylene produced by these low-pressure processes has high density, high degree of crystallinity, improved melting point and elevated softening temperature,
and has a relatively greater stiffness than polyethylene produced by high pressure processes. It is known that polyethylene produced by either high pressure or low pressure processes can be thermally decomposed to produce substantially lower molecular weight products. In fact, pyrolysis processes can be used to produce polyethylene waxes consisting of high molecular weight polymers.
Thermal decomposition of polyethylene is often carried out under an inert atmosphere, such as nitrogen, to prevent oxidation of the decomposed polymer. The polyethylene used in this study can be produced by either a so-called high pressure method or a low pressure method, and can also be obtained from polyethylene by a decomposition method or the like. A suitable method for making high pressure polyethylene is described in US Pat. No. 2,153,553.
Suitable polyethylenes can also be obtained by low pressure methods. In carrying out the low pressure polymerization reaction, it is possible to use well known polymerization catalysts for polymerizing ethylene into highly crystalline polymers at low pressure. Among the catalysts that can be used are aluminum trialkyl type catalysts. For example, aluminum triethyl mixed with a titanium tetrahalide such as titanium tetrachloride or aluminum triethyl mixed with a vanadium halide such as vanadium trichloride can be used. Other suitable catalyst mixtures are mixtures of aluminum metal and titanium tetrahalides, such as titanium tetrachloride, or mixtures of sodium amyl and titanium tetrachloride. Furthermore, metal oxide catalysts can also be used. For example, catalysts consisting of chromium oxide and silicon oxide deposited on activated alumina, as well as molybdenum oxide deposited on activated alumina, are also used. Catalyst mixtures consisting of vanadium pentoxide deposited on activated alumina can also be used. For example, highly crystalline, high density polyethylene can be produced in a low pressure process using a catalyst mixture of aluminum and titanium tetrachloride to carry out the polymerization reaction. Details of operating such a process using this catalyst mixture can be found in USSU559536.
It is stated in In this process, the polymerization reaction is generally carried out in the liquid phase of an inert organic solvent, preferably in an inert liquid hydrocarbon. This reaction takes place over a relatively wide temperature range, preferably between 20 and 200°C.
and particularly favorable results have been carried out in the range of 40
Obtained in the range of ~160°C. The reactivity should be chosen in the range from 1 atm to about 70 atm, although high pressures can be used if necessary in some cases, and the inert organic solvent should be used in the liquid medium and at the polymerization temperature to form solid polyethylene. It is desirable to serve as a solvent for A pressure of 20 to 35 atmospheres is most preferred since increasing pressure significantly increases the polymerization rate. The organic solvent used in this polymerization reaction is usually an aliphatic saturated hydrocarbon or a cyclic saturated hydrocarbon such as hexane, heptane, or cyclohexane. It is also possible to use hydrogenated aromatic compounds such as tetrahydronaphthalene and decahydronaphthalene, if necessary. Furthermore, aromatic hydrocarbons such as benzene, toluene, xylene, etc., or chlorobenzene,
Halogenated aromatic compounds such as chloronaphthalene or orzochlorobenzene are also very satisfactory. Preference is given to using liquid hydrocarbons.
Other liquid solvents that can be used include ethylhenzene, isopropylbenzene, ethyltoluene, n
- propylbenzene, diethylbenzene, mono and diethylbenzene, mono and dialkylnaphthalenes, n-pentane, n-octane, iso-octane, methylcyclohexane, tetralin, decalin and other well-known inert liquid hydrocarbons. The amount of solvent used when carrying out this polymerization reaction can be chosen within a wide range depending on the monomer and catalyst mixture. Best results are obtained when using catalyst concentrations of about 0.01 to 10%, preferably 0.1 to 5% by weight of the solvent. The most preferred catalyst concentration is in the range 0.1-2% by weight. The monomer concentration in the solvent can vary quite widely and is usually in the range from 2 to 50% by weight of the solvent, preferably from 2 to 10%, per gram atom of aluminum metal when using a catalyst mixture of aluminum and titanium tetrachloride. About 1 to 6 molecular equivalents of titanium tetrachloride. In order to produce high-density, extremely crystalline, high-molecular-weight polyethylene, it is preferable to reduce the ratio of titanium tetrachloride to aluminum metal, and under these conditions, it is possible to set the temperature range described above to a low value. More preferred. When using a catalyst mixture of sodium amyl and titanium tetrachloride, the ratio of titanium tetrachloride to sodium amyl is small, and the polymerization temperature is, for example, −30 to 30°C.
It is preferable to set it at ℃. The catalyst ratio is preferably in the range of 1/20 to 1/4 mole of sodium amyl to titanium tetrachloride. Polyethylene produced under these conditions has a very high density and a very high molecular weight. Furthermore, this polyethylene is insoluble in many hydrocarbon solvents and is difficult to mold or extrude under normal conditions. Polyethylene produced by the low pressure process is highly crystalline and usually exhibits at least 80% crystallinity by radiography; polyethylene produced by the low pressure process has an average crystallinity of about 90% or more. Examples of manufacturing the polyolefin according to the present invention are shown below. Production example Magnesium oxide was filled in a quartz vertical reactor with a diameter of 25 mm and a length of 1 m. Dry nitrogen gas saturated with titanium tetrachloride was introduced from the bottom of the reactor and reacted at a temperature of 120°C for 4 hours. Ta. During the reaction, the temperature of the saturator for saturating nitrogen gas with titanium tetrachloride was 83° C., and the flow rate of nitrogen gas was maintained at a linear velocity of 100 cm/min at the inlet at the lower end of the reactor to form a fluidized bed. The total amount of titanium tetrachloride used in the reaction was 108 ml. After the reaction of titanium tetrachloride, dry nitrogen gas was introduced and the mixture was calcined at a temperature of 400° C. for 2 hours to prepare a catalyst. The flow rate of the dry nitrogen gas at that time was a linear velocity of 50 cm/min at the inlet at the lower end of the reactor. 0.5g of the obtained catalyst and triethylaluminum
40ml was introduced into an autoclave with a capacity of 500ml along with 200ml of cyclohexane, the inside of the autoclave was sufficiently replaced with nitrogen gas, and hydrogen gas was 7Kg/cm ² at room temperature.
was injected under pressure, and after raising the temperature to 180°C, constant pressure polymerization was carried out for 40 minutes at a total pressure of 50 kg/cm ² while continuously supplying a mixed gas of ethylene and propylene (mixing ratio 10:1). . The obtained polyethylene is
The number average molecular weight (Mn) is 4500, the weight average molecular weight (Mw)/number average molecular weight (Mn) is 6.0, and the total enthalpy of fusion (△Hm) is 59.5 cal/g.
90% of the total melting enthalpy was above 110℃, and 63% of the total melting enthalpy was above 120℃. Furthermore, another type of polyethylene can be obtained by decomposing the obtained polyethylene. This decomposition requires the presence of hydrogen. Inert gases such as nitrogen, argon, and helium can also be allowed to coexist in the decomposition gas along with hydrogen. However, it is important to keep the oxygen content in the decomposition gas to a minimum to avoid oxidation of the decomposed polyethylene at the decomposition temperature. The amount of hydrogen used during pyrolysis can vary from less than about 1 atmosphere to about 300 atmospheres. Higher hydrogen pressures can be used, but are usually not necessary. Generally, it is desirable to use hydrogen at a pressure no greater than that which can be tolerated by the cracker utilized. Significant improvements in the decomposition of polyethylene can be achieved by carrying out the decomposition in a stream of hydrogen at atmospheric pressure. but,
The most desirable results in pyrolysis are achieved when carrying out the process at pressures of tens of atmospheres. Thermal decomposition of polyethylene typically occurs at temperatures ranging from 250 to 450°C;
and is generally carried out for a period of time ranging from 5 minutes to about 3 hours. It has been noted that the temperatures required to produce thermally decomposed polyethylene of constant molecular weight are typically lower when this decomposition is carried out in the presence of hydrogen. The use of lower temperatures is desirable because it minimizes undesirable side reactions that normally occur at higher temperatures. As mentioned above, most of the conventional toners intended for pressure fixing have used polyolefin as the main binder. In this process, it is becoming clear what kind of polyolefin makes pressure fixing possible. Unfortunately, however, the mechanism of pressure fixation itself is still in the realm of speculation. Therefore, it can be said that the specific form of the polymeric material exhibiting such pressure fixation depends mostly on what is obtained empirically. As already mentioned, the present inventors have been conducting intensive research on polyolefin, which is widely known as a pressure fixing material. Factors that should specify the state of these polyolefins include the average molecular weight, that is, the weight average molecular weight Mw, the number average molecular weight Mn, and their ratio, molecular weight distribution, crystal ratio, vitrification temperature, melting enthalpy equilibrium melting point, melt viscosity, and compressive yield. points, compressive fracture strength, etc. These factors are interrelated, influence each other, and complement each other to determine a certain state. As the present inventors progressed with their studies on polyolefins, they discovered that the molecular weight and molecular weight distribution in particular have an extremely powerful effect on solving the various problems of pressure fixing toners mentioned above. According to the studies conducted by the present inventors, the manner in which pressure-fixed toner is pressure-fixed, which has been considered in the past, is based on concepts such as entanglement and penetration into paper fibers. That is, the conclusion has been drawn semi-ideally and intuitively that it must have a certain degree of elasticity, a certain degree of plastic deformability, and stretchability. In fact, such a resin allows fixing by pressure, and good fixing is expected. It is undeniable that the present inventors had such an awareness at the very early stage leading up to the present invention. However, in our study of the polyolefins mentioned above, we discovered a polyolefin that exhibits completely different behavior and has a pressure fixing ability. Although this polyolefin was extremely hard and had extremely poor stretchability compared to conventionally used polyolefins, it was able to be sufficiently fixed by pressure. It has been found that the effect thought to be due to this is significantly reflected in the offset property, and some polyolefins do not show any offset at all. The conclusions based on the studies conducted by the present inventors depend entirely on the molecular weight and molecular weight distribution mentioned above.
That is, the number average molecular weight Mn is 2000 to 5000, more preferably 2000 to 4000, and the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight is 2.8 or more,
It has been found that polyolefins tend to have a more preferable value of 3.0 or more and 10.0 or less. The results regarding fixing of polyolefin shown in Table 1 are summarized in Table 2. The numbers are the same as those in Table 1. The pressure required for fixing is shown in linear pressure. Most of these polyolefins are harder and less stretchable than commonly used polyolefins. As mentioned above, the present inventors have obtained or prototyped polyolefin for the purpose of examining its developability and stability as a toner, but at this time they completely ignored fixing properties due to pressure. It is. Like other researchers in this field, I had been thinking of achieving fixation by mixing wax with such polyolefins, but as you can see here, the molecular weight was much larger than that of the waxes normally used.
Furthermore, it is surprising that a product with a wide distribution exhibits pressure fixing properties that deviate from conventional sensations. The present inventors believe that the form in which this type of polyolefin is fixed by pressure is different from the form in which it is fixed by conventional wax components.

【table】

[Table] Although we have some predictions, detailed elucidation will be left to future research. As mentioned above, it has been found that toners using this polyolefin are extremely effective in solving the problems of conventional pressure fixable toners due to their molecular weight and molecular weight distribution. That is, easy and high productivity based on easy crushability in toner production, improved fusion resistance, and improved impact resistance. It has also been found that the stability of the toner is significantly superior to toners based on the prior art, which is thought to be due to the wide molecular weight distribution. The present inventors have continued to study the effect of molecular weight, but in this regard, based on the present inventors' conventional view regarding only the molecular weight, development by triboelectric charging is applicable regardless of whether it is a two-component system or a one-component system. Polyolefin toners with a molecular weight of 5,000 or more are particularly effective, and polyolefins with a molecular weight of over 10,000 are particularly effective in fusing to carriers, metal sleeves, photoreceptor surfaces, etc. In addition, by suppressing the portion with a molecular weight of 10,000 or less to 50% by weight or less of the total, coagulation,
Caking can be suppressed as much as possible. This tendency is closely intertwined with offset property, and it has been found that the decrease in caking and the decrease in offset property exhibit exactly the same tendency, probably due to molecular weight effects. In addition, the stability of the binder resin itself has an extremely strong effect, and it would be an accurate judgment to view this as a synergistic effect. It is believed that polyolefin having a high molecular weight leads to good image quality due to its stable internal energy state in the usage environment. On the other hand, toners made of polyolefins with a molecular weight of 50,000 or less produce the completely opposite effect. That is, the effects described so far can be summarized as mainly related to developability, but all of them are in the direction of being poor when compared with those of molecules having a molecular weight of 10,000 or more. However, the pressure fixing properties are in a more favorable direction. FIG. 1 qualitatively shows the fixing properties at various linear pressures depending on the weight average molecular weight. ABC is linear pressure of roll 35Kg/cm, 25
Kg/cm, 15Kg/cm, and the retention rating is 5 Excellent, 4
Good, 3 acceptable, 2 unacceptable, 1 not fixed. As can be seen from this, it has been found that those having a small molecular weight are extremely effective in improving pressure fixing properties. Polyolefins having such small molecular weight portions are expected to exhibit good fixing properties at lower pressures depending on their proportions. Furthermore, such polyolefins can be easily pulverized using a supersonic jet mill or the like, resulting in extremely high productivity. This toner is characterized by containing a composite of polyolefins having a small molecular weight and a large molecular weight. An even more preferable feature is that the above-mentioned effects of large and small molecular weight molecules can be more effectively achieved by widening the molecular weight distribution. It is true that the above-mentioned effects can be expected by mixing substances with large and small molecular weights, and this is exactly the opinion based on the facts of the present inventors. However, in order to carry out the present system more preferably, a molecule having an intermediate molecular weight that connects these large and small portions is required. The behavior of molecules with this intermediate molecular weight is currently unclear. From many other experiments conducted by the present inventors, it has been found that the more molecules there are in terms of molecular weight, the more preferable it is to have a continuous distribution from small to large. It is said that By mixing two types of polyolefins with different molecular weights, a new composite material that combines the advantages of both can be obtained. However, depending on how it is mixed, it may have the disadvantages of both. In fact, we have tried various methods of this mixing and have obtained better results in many cases, but not in all cases. Quite the contrary, it is also true that a small number of products with more defects were obtained. The present inventors investigated a method for embodying the above-mentioned molecular weight effect in a more correct sense, and the resulting method was to use a polyolefin having a continuous molecular weight distribution. A mixture of polyolefins in which the molecular weights are successively lowered from those with extremely high molecular weights and those whose molecular weights are increased successively from those with very low molecular weights are extremely effective in achieving the present invention. Due to this, 2
The effect obtained is far superior to that achieved by the most successful forms of mixtures of polyolefins of different molecular weights. Regarding this matter, the present inventors have not yet come to understand the cause of the effect of the polyolefin having such an intermediate molecular weight, but presently they have proposed the following opinion. That is, it is essentially difficult to mix a polyolefin with a large molecular weight and a polyolefin with a small molecular weight, and in this mixed state, an intermediate molecular weight polyolefin can serve as an intermediate binding medium. The affinity between two types of polyolefins having different molecular weights increases when their molecular weights are close to each other when their skeletal structures are similar. This guarantees extremely orderly arrangement, that is, crystallinity, and can be expected to reduce the entropy term of internal energy. The presence of polyolefins with similar molecular weights is expected to have an effect. This will help you understand the effect of gradually lowering the molecular weight. The reason why this toner system works extremely effectively is that these low molecular weight molecules have a continuous affinity with high molecular weight molecules, so that they act as part of the high molecular weight molecules in developability and as a single low molecular weight molecule in fixing. This is because it is thought that it may be functioning. As is clear from the above discussion, the toner of the present invention is made up of two major factors. It is an entropy effect and a molecular weight effect. That is, the number average molecular weight Mn is 2000 to 5000, more preferably 2000 to 4000, and the ratio Mw/Mn of the weight average molecular weight to the number average molecular weight is 2.8 or more,
More preferably, it is 3.0 or more and 10.0 or less, and at least 50% of the total melting enthalpy is
In the range of 110°C or higher, more preferably at least 30°C
A toner containing polyolefin having a temperature of 120° C. or higher is excellent in developability, fixability, and other physical properties as a toner, and is stable. The above-mentioned polyolefin may be used alone as a binder in the pressure fixable toner of the present invention, but it is sufficient that it is contained in the toner to an extent that satisfies the pressure fixability. Other resins, waxes, etc. may be mixed and used for the purpose of improving properties. For example, polystyrene, poly-P-chlorostyrene, polyvinyltoluene,
Polymers or copolymers of styrene and its substituted products, such as styrene-butadiene copolymers and styrene-acrylic acid copolymers, polyvinyl chloride, general polyethylene, polyvinyl acetate, polypropylene, polyester resins, acrylic resins, silicones Resin, epoxy resin, xylene resin, polyamide resin, ionomer resin, furan resin, ketone resin, terpene resin, phenol-modified terpene resin, rosin, pentaerythritol ester of rosin, natural resin-modified phenolic resin, natural resin-modified maleic acid resin, Malonindene resin, maleic acid-modified phenolic resin, alicyclic hydrocarbon resin, petroleum resin, cellulose phthalate acetate, carboxymethyl cellulose, methyl vinyl ether
Maleic anhydride copolymer, polyvinyl butyral, polyvinyl alcohol, polyvinylpyrrolidone, cyclized rubber, chlorinated paraffin, wax, fatty acid, etc. can be used. These resins may be used in combination so as not to impair various properties such as pressure fixing properties of the polyolefin according to the present invention. The amount of polyolefin in the toner binder varies depending on the type of resin mixed, but generally 5.
A content of at least 20% by weight, preferably at least 20% by weight, provides good pressure fixing properties. As the colorant used in the toner of the present invention, all the dyes and pigments conventionally used in electrostatic latent image toners can be used, and of course, charge control agents and the like can also be used.
Further, when it is desired to obtain a magnetic toner, it is sufficient to mix magnetic fine powder such as magnetite, ferrite, iron powder, etc. Even in this case, the pressure fixability was good. The image obtained with the toner of the present invention is fixed by passing between a pair of pressure-loaded rollers, but auxiliary heating may be applied. The applied pressure is generally about 15-35 kg/cm. Regarding the pressure fixing device, Japanese Patent Publication No. 44-12797, U.S. Pat. No. 3,269,626, U.S. Pat. No. 3,612,682,
It is described in Specification No. 3655282, Specification No. 3731358, etc. The present invention will be explained in more detail below using examples. Example 1 Polyethylene (No. 1) in Γ Table 1
100 parts by weight Γ magnetite 80 〃 The above materials were mixed in a porcelain ball mill pot, further kneaded with two roll mills heated to 140°C, then crushed with an ultrasonic jet air flow mill, and then subjected to a classification operation using wind power. The toner particles of 5 to 30 microns were separated. The toner produced as described above was applied to a developing device having a magnetic sleeve to develop an electrostatic latent image on a photoconductive material, and then transferred onto plain paper using corona charging, resulting in a clear, fog-free image. was gotten. Next, the image on the transfer paper is applied with a linear force of 25 kg/
It was completely fixed when passed between hard steel rolls with a diameter of 10 cm that were pressed against each other with a diameter of 10 cm. Then, when continuous copying was performed using a copying machine, images almost the same as the initial images were obtained even after 20,000 copies were used. Example 2 100 parts by weight of polyethylene (No. 2) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 3 100 parts by weight of polyethylene (No. 3) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 4 100 parts by weight of polyethylene (No. 7) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 5 100 parts by weight of polyethylene (No. 15) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 6 100 parts by weight of polyethylene (No. 16) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 7 100 parts by weight of polyethylene (No. 17) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 8 100 parts by weight of polyethylene (No. 22) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 9 100 parts by weight of polyethylene (No. 23) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, an image test durability test was conducted in the same manner as in Example 1, and the characteristics were almost the same. Example 10 100 parts by weight of polyethylene (No. 1) shown in Table 1 and carbon black (Regal manufactured by CABOT)
400R) was kneaded in a roll mill, pulverized, and then classified to obtain a toner having a particle size of 5 to 15 μm. 10 parts by weight of this toner and 90 parts by weight of reduced iron powder of 30 to 60μ are mixed and applied to a two-component developing machine with a magnetic sleeve to develop a photoreceptor with an electrostatic latent image, and then transferred to plain paper to make two copies. The images were fixed using a pressure fixing device consisting of a rigid roller. The image was clear and completely fixed at a linear pressure of 25 kg/cm. Furthermore, even after 50,000 sheets were continuously copied, almost the same image as the initial image was obtained. Example 11 100 parts by weight of polyethylene (No. 2) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 12 100 parts by weight of polyethylene (No. 3) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 13 100 parts by weight of polyethylene (No. 7) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 14 100 parts by weight of polyethylene (No. 15) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 15 100 parts by weight of polyethylene (No. 16) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 16 100 parts by weight of polyethylene (No. 17) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 17 100 parts by weight of polyethylene (No. 22) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Example 18 100 parts by weight of polyethylene (No. 23) shown in Table 1 5 parts by weight of carbon black The above materials were mixed and pulverized in the same manner as in Example 10 to obtain a toner. In addition, an image test durability test was conducted in the same manner as in Example 10, and the characteristics were almost the same. Comparative Example 1 100 parts by weight of polyethylene (No. 8) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. In addition, when an image test durability test was conducted in the same manner as in Example 1, fixing was insufficient with a linear force of 20 kg/cm, and when a durability test was conducted, the toner agglomerated after about 10,000 sheets and almost no image appeared. It was hot. Comparative Example 2 100 parts by weight of polyethylene (No. 9) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. In addition, when an image test durability test was conducted in the same manner as in Example 1, fixing was insufficient with a linear force of 20 kg/cm, and when a durability test was conducted, the toner agglomerated after about 10,000 sheets and almost no image appeared. It was hot. Comparative Example 3 100 parts by weight of polyethylene (No. 14) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. In addition, when an image test durability test was conducted in the same manner as in Example 1, fixing was insufficient with a linear force of 20 kg/cm, and when a durability test was conducted, the toner agglomerated after about 10,000 sheets and almost no image appeared. It was hot. Comparative Example 4 100 parts by weight of polyethylene (No. 19) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. In addition, when an image test durability test was conducted in the same manner as in Example 1, fixing was insufficient with a linear force of 20 kg/cm, and when a durability test was conducted, the toner agglomerated after about 10,000 sheets and almost no image appeared. It was hot. Comparative Example 5 100 parts by weight of polyethylene (No. 10) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. In addition, when an image test durability test was conducted in the same manner as in Example 1, fixing was insufficient with a linear force of 20 kg/cm, and when a durability test was conducted, the toner agglomerated after about 10,000 sheets and almost no image appeared. It was hot. Comparative Example 6 100 parts by weight of polyethylene (No. 5) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image durability test was conducted in the same manner as in Example 1, the toner was fused and almost no image appeared after about 3,000 sheets. Comparative Example 7 100 parts by weight of polyethylene (No. 6) shown in Table 1 80 parts by weight of magnetite The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image test durability test was conducted in the same manner as in Example 1, the toner was fused after about 3,000 sheets and almost no image appeared. Comparative Example 8 Polyethylene (No. 4) in Table 1 100 parts by weight Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image durability test was conducted in the same manner as in Example 1, the toner was fused and almost no image appeared after about 3,000 sheets. Comparative Example 9 Polyethylene (No. 11) in Table 1 100 parts by weight Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image test durability test was conducted in the same manner as in Example 1, the toner was fused after about 3,000 sheets and almost no image appeared. Comparative Example 10 Polyethylene (No. 12) in Table 1 100 parts by weight Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image durability test was conducted in the same manner as in Example 1, the toner was fused and almost no image appeared after about 3,000 sheets. Comparative Example 11 100 parts by weight of polyethylene (No. 13) in Table 1 Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image test durability test was conducted in the same manner as in Example 1, the toner was fused after about 3,000 sheets and almost no image appeared. Comparative Example 12 100 parts by weight of polyethylene (No. 18) in Table 1 Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image durability test was conducted in the same manner as in Example 1, the toner was fused and almost no image appeared after about 3,000 sheets. Comparative Example 13 100 parts by weight of polyethylene (No. 25) in Table 1 Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image test durability test was conducted in the same manner as in Example 1, the toner was fused after about 3,000 sheets and almost no image appeared. Comparative Example 14 Polyethylene (No. 21) in Table 1 100 parts by weight Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image durability test was conducted in the same manner as in Example 1, the toner was fused and almost no image appeared after about 3,000 sheets. Comparative Example 15 Polyethylene (No. 24) in Table 1 100 parts by weight Magnetite 80 The above materials were mixed and pulverized in the same manner as in Example 1 to obtain a toner. Further, when an image test durability test was conducted in the same manner as in Example 1, the toner was fused after about 3,000 sheets and almost no image appeared.

[Brief explanation of the drawing]

FIG. 1 is a graph qualitatively showing the weight average molecular weight of polyolefin and the fixing properties at various linear pressures.

Claims (1)

[Claims] 1 Number average molecular weight Mn is 2000 to 5000, and the ratio of weight average molecular weight Mw to number average molecular weight
A polyolefin having Mw/Mn of 2.8 or more, at least 50% or more of the total enthalpy of melting of the polyolefin is at 110°C or more, and at least 30% or more of the total enthalpy of melting is at 120°C
A pressure fixing toner characterized by containing the above polyolefin.