JPS649628B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to heat-fusible toner powders for electrostatic latent image development. The toner powder of the present invention consists of finely divided colored toner particles containing substantially an insulating thermoplastic resin and a coloring substance. The present invention particularly relates to a toner powder whose insulating thermoplastic resin is mainly composed of an epoxy resin. The present invention also provides a method for producing the toner powder, a two-component type developer containing the toner powder mixed with a carrier, a one-component type developer comprising the toner powder, and a static developer using the toner powder. It also relates to electro-latent image development. Two-component and one-component developers having toner particles containing an insulating thermoplastic resin and a colorant are commonly applied to electrostatic latent image development. The electrostatic latent image is
Obtained, for example, by electrography or electrophotography on a suitable support. The electrostatic latent image is
For example, it is the anode in electrophotographic elements based on selenium, and the cathode in electrophotographic elements based on zinc oxide and many organic photoconductors. Insulating thermoplastic resins proposed for application in toner powders include polystyrene, copolymers of styrene with acrylates and/or methacrylates, polyamides, phenol-formaldehyde resins, polyesters and to a small extent epoxy resins. The colored material used in black toner powders applied in two-component developers is usually carbon black, whereas the colored material in black toner powders used as single-component developers is usually primarily finely divided. magnetic material such as iron powder chromium oxide or nickel ferrite. For example, in colored toner powders used in multicolor copying methods, organic dyes are usually added to thermoplastic resins. During development of the electrostatic latent image, toner powder is deposited on the charged image areas that become the visible image. One-component developer is
It can be used for the development of anodic electrostatic images as well as cathodic electrostatic images without any special conditions required for this purpose. In two-component developers, the carrier mixed with the toner powder must be selected so that the toner powder obtains the desired triboelectric charge. Commonly applied carriers include iron, nickel, metal oxide, sand or quartz particles of the desired size. If desired, the particles may be coated with a polymer. A developer that is cathodically charged is mainly used for developing an anodic electrostatic image, and a developer that is anodically charged is mainly used for developing a cathodic electrostatic image. During development, toner powder is deposited on the charged latent image areas that become the visible image. Powder images formed by one-component or two-component developers can be fused directly to the surface on which they are carried. This case is called direct electrophotography. In what is referred to as indirect electrophotography, the powder image is transferred to a suitable receiver sheet and then fixed. The fixing is usually by the application of heat, for example in so-called radiation or flash fusing devices, or by the application of heat in so-called contact fusing devices, where the powder image is fixed in contact with heated surfaces such as rollers and/or belts. It will be done. In addition to the above-mentioned components, toner powders often contain one or more other known components, in particular plasticizers and polarity modifiers. The basic conditions that toner powder must meet in order to obtain good results are that it has appropriate polarity, sufficient chargeability, uniform charge distribution, and excellent chargeability properties such as charge stability. , low sensitivity to humidity and temperature, good meltability for copying, and excellent thermal stability and durability even in long-term use.
Furthermore, in order to save melting energy, it is desirable that the temperature at which the toner powder begins to melt is as close as possible to the minimum glass transition temperature required for its thermal stability, typically in the range of 45 to 80°C. . Further, when toner powder is melted by contact, it is desirable that the melting range be as wide as possible, preferably several tens of degrees (centigrade).
This is necessary in order to reduce as much as possible the formation of so-called ghost images and contamination of the fusing roller due to the transfer of parts of the powder image to the fusing roller and from the fusing roller to the copy paper. be. The lower limit of the melting range is the lowest temperature at which an image is sufficiently fixed, and the upper limit is the temperature at which a ghost image is first formed. It is an object of the present invention to provide a toner powder that is capable of being cathodically charged in triboelectric contact with metal carrier particles and that is highly stable under normal conditions of storage and use, yet fully exhibits the desirable properties of toner powders summarized above. Our goal is to provide you with toner powder. Another object of the present invention is to provide a toner powder with a low glass transition temperature, and the lower limit of the melting range of the toner powder is significantly lower than the glass transition temperature compared to the case of normally applied toner powders. Close to each other. The present invention comprises finely divided toner particles containing an insulating thermoplastic resin and a colorant, wherein the insulating thermoplastic resin is one or more of the insulating thermoplastic resins having at least 50% of the total number of epoxy groups blocked. It is mainly composed of modified resins that are derivatives of the above epoxy resins, at least 5% of which is partially blocked by a chemical reaction with a monofunctional carboxylic acid, phenol or diarylsulfonamide, and the epoxy resin It is partially blocked by an intermolecular reaction with the hydroxyl group ^of The present invention relates to a heat-fusible toner powder for electrostatic latent image development, characterized in that the toner powder does not contain an anodic charge control agent. In order to meet the requirement that the toner powder of the present invention be stable under normal conditions of storage and use, at least 50% of the total number of epoxy groups in the starting epoxy resin must be blocked as described above. . The percentage of the total epoxy groups of the starting epoxy resin that must be blocked to achieve the desired stability depends on the reactivity of the starting epoxy resin. The higher the reactivity of the starting epoxy resin, i.e. the lower the epoxy-molar-mass of the starting epoxy resin, the higher the percentage of blocked epoxy groups must be to obtain a stable toner powder. No.
“Epoxy value” refers to the number of grams of resin containing 1 gram equivalent of epoxy (“Handbook of
Epoxy Resins”Lee and Neville, McGrawhill
(See Book Company, 1967, pp. 4-14). In the following, the epoxy value is abbreviated as EMM. The epoxy group of the starting epoxy resin is such that the total EMM of components (1) and (2) in the toner powder of the present invention is at least
Preferably, it is blocked to some extent at 8000. The average EMM and percentage of blocked epoxy groups required to increase the EMM to a given high value for some of the most readily available commercially available epoxy resins are listed in the table below.

[Table] From the table above, in the case of Epicote 1009, it is approximately 8000
In order to obtain a resin with an EMM of Without it, it is clear that the purpose will not be achieved. For low molecular epoxy resins, several thousand EMMs
It should be noted that the increase in .sub.2 actually corresponds to an increase in the number of blocked epoxy groups by only a few percent. Therefore, component (1) in the toner powder of the present invention
and (2) the total EMM of preferably at least
It will be clear that the requirement of 8000 must be taken as a rather less stringent requirement, the lower the molecular weight of the starting resin. The sensitivity of EMM as a measure of the reactivity remaining in the thermoplastic resin component clearly decreases as the molecular weight of the epoxy resin used as starting material decreases, whereas the EMM number as a measure of reactivity This is considered to be the most convenient criterion for judgment at present. The modified epoxy resins used in the toner powders of the present invention can be most economically produced from commercially available epoxy resins. It is also possible to use mixtures of the aforementioned resins. By epoxy resin herein is meant a condensation product of a polyphenol, especially 4,4'-isopropylidene-diphenol, and a halohydrin, especially 1-chloro-2,3-epoxypropane. As is well known, commercially available epoxy resins usually have a molecular weight of less than 4000
Has EMM. Epikote 1001 (melting point 60-70°C, E.
MM450−500), Epicote 1004 (melting point 90−100
°C, EMM850−940), Epicote 1006 (melting point 115
−125℃, EMM1500−1900) Epicote 1007
(melting point 120-130℃, EMM1700-2050), Epicote 1009 (melting point 140-155℃, EMM2300-3400)
For example, Also, a mixture of two or more of these resins may be used. For some methods of implementation, it may be advantageous to use a liquid epoxy resin as a starting material, as explained below. Which blocking method or combination of the above methods is selected depends on the method by which the toner powder is fixed. The applicant has determined that when the toner powder of the present invention is radiation melted, the viscosity of the toner powder (measured at 140°C) is between 2 and 1000 Nsm ^-2 and its glass transition temperature (Tg) is between 45 and 65°C. We found that this is preferable. When using contact-melting equipment, the viscosity measured at 140°C is 200-200000 sPa.
It is preferable that the Tg is 45 to 80°C. Blocking with monofunctional carboxylic acids, phenols or diaryl-sulfonamides results in the desired increase in the EMM of the starting epoxy resin, but
It does not substantially increase its molecular weight and viscosity. This blocking method is therefore very advantageous when producing modified epoxy resin fractions of toner powder used in radiation fusing equipment. The above parameters for suitable viscosity and Tg for toner powder fixed by radiation are usually:
At least 50%, preferably at least 70%, of the initial epoxy groups of the modified epoxy resin or mixture of epoxy resins are reacted with monofunctional carboxylic acids, phenols or diaryl-sulfonamides, preferably without reaction with epoxy hardeners. It can be obtained by blocking it by a chemical reaction of 5% to 10% by a small amount of intermolecular reaction. The monofunctional carboxylic acids, phenols or di-arylsulfonamides used within the scope of the present invention are the epoxy groups of the starting resin under the conditions of the blocking step, excluding the carboxyl, hydroxyl and sulfonamide groups, respectively. It should not contain any further reacting displacement devices. As carboxylic acids, aliphatic carboxylic acids and aromatic carboxylic acids can be used in the blocking step. Useful resin family carboxylic acids are, for example, heptanoic acid, nonanoic acid, dodecane and isododecanoic acid, hexadecanoic acid and octadecanoic acid. Also, aromatic carboxylic acids and aromatic carboxylic acids substituted with one or more of alkyl, aralkyl, cycloalkyl, aryl, alkylaryl, alkoxy or aryloxy groups, which under the conditions of the blocking reaction substantially Good results can also be obtained with materials that are non-volatile. As the aromatic carboxylic acid, benzoic acid, 2,4-dimethylbenzoic acid, 4-(α,α-dimethylbenzyl)-
Examples may include substituted benzoic acids such as benzoic acid, 4-phenylbenzoic acid, 4-ethoxybenzoic acid. Furthermore, perfluoro-carboxylic acids such as perfluorobutyric acid, perfluoro-octanoic acid and perfluoro-decanoic acid can also be applied. A group of phenols that are particularly useful for blocking are those substituted with one or more of the following: alkyl, aralkyl, cycloalkyl, aryl, alkylaryl, alkoxy or aryloxy groups, which under the blocking reaction conditions substantially Examples include phenols that do not volatilize. The phenols include 4-n-butylphenol, 4-n-pentylphenol, 2,3,
4,6-tetramethylphenol, 2,3,5,
Examples include 6-tetramethylphenol, 4-(α,α-dimethyl)benzylphenol, 4-cyclohexylphenol, 3-methoxyphenol, 4-methoxyphenol, and 4-ethoxyphenol. Examples of useful di-aryl-sulfonamides are:
Benzene-sulfonanilide and derivatives of benzene-sulfonanilide in which one or two benzene nuclei have one or more lower alkyl or alkoxy groups. Among the above compounds, benzoic acid, substituted benzoic acids, 4-(α,α-dimethyl)benzylphenol and p-toluenesulfonanilide have been found to be particularly useful. In order to obtain the above viscosity and Tg parameters suitable for the toner powder used for contact fusing, the modified epoxy resin is a low molecular weight fraction with a molecular weight of 4000 or less and a 4000 ml that may or may not be cross-linked.
It should preferably contain a polymer fraction with a molecular weight of 10,000 or more. Modified epoxy resins containing low molecular weight fractions and high molecular weight fractions can be prepared by modifying the epoxy groups of commercially available epoxy resins or mixtures of epoxy resins by chemical reaction with, for example, monofunctional carboxylic acids, phenols or di-aryl-sulfonamides. by blocking at least 5%, preferably from about 10 to 35% depending on the resin, while blocking the remaining epoxy groups up to at least 50% of the total epoxy groups by intermolecular reaction with the alcoholic hydroxyl groups of the resin. can get. The first blocking method yields a low molecular fraction;
A macromolecular fraction is obtained from the subsequent blocking process. The two types of blocking methods can be performed at once or sequentially. In the latter case a high viscosity and a wide melting range are obtained, but the Tg is the same as when both processes are carried out at once. However, the desired polymer fraction is
It can also be obtained by reacting a portion of the epoxy groups of the starting resin with a di- or polyfunctional epoxy curing agent. In this case, linear or crosslinked structures are obtained. In this case too, the reactions can be carried out simultaneously or sequentially. The most suitable epoxy curing agent was found to be 4,4'-isopropylidene diphenol. A third possibility for obtaining the polymer fraction is to produce the polymer fraction by a single method or to buy it commercially. Subsequently, the high molecular fraction may be mixed with the low molecular fraction produced by any of the above methods. 4,4'- for the production of polymer fractions
When using isopropylidene diphenol,
The product is commonly referred to as phenoxy resin. Phenoxy resin has a substantially linear molecular structure,
It has a molecular weight of 10,000 to 80,000. An example of a suitable commercially available phenoxy resin is Ryutapox 0717 (molecular weight 30,000) manufactured by Bakelite. Generally, the increase in molecular weight of the starting epoxy resin by epoxy curing agents is much higher and faster than the increase obtained by intermolecular reactions. When the epoxy curing agent is used to obtain a polymeric fraction, at least about 40-75% of the total initial epoxy groups of the modified epoxy resin are combined with monofunctional carboxylic acids, phenols or di-aryl-sulfonamides. It is mostly blocked by chemical reactions, and only a small part is blocked by intermolecular reactions, and at most 25
-60% is preferably blocked by reaction with the epoxy hardener. The toner powder of the present invention can be produced by any of various known methods for producing toner powder, such as a kneading method, an extrusion method, or a hot melt method.
In kneading and extrusion methods, the resin, colorant, and optionally other ingredients such as polar modifiers are usually mixed together at a temperature of about 90-160°C. In the hot melt method, mixing is usually performed at a temperature of about 200°C. After cooling, the resultant is ground into particles of the desired size, usually 2 to 50 μm. It is also possible to spray the hot melt into the cooling space to obtain particles of the desired size. It has been found that of the above three manufacturing methods, the hot melt method and the kneading method are most suitable for manufacturing the toner powder of the present invention. It has been found that the toner powders produced by these two methods are very satisfactory with respect to the basic properties, in particular the charging behavior, stability, melting properties, and the copying results are also good. This is believed to be due to the fact that the temperature and reaction time can be easily controlled. Furthermore, the above 2
Two methods have been found to be optimal for carrying out the blocking reaction of the epoxy groups of the starting resin to obtain the desired modified epoxy resin during the manufacture of the toner powder itself. This offers many advantages over manufacturing modified resins separately. Therefore, the toner powder of the present invention has a temperature of about 150 to 250
The starting epoxy resin or mixture of epoxy resins in the molten state at It is desirable that the compound be produced by carrying out the following reaction. During the mixing process, the blocking reaction is
Proceed to the final stage easily and without difficulty. When di-aryl-sulfonamides are used in the blocking reaction, it is preferred to block the epoxy groups of the starting resin with the amide, but mild blocking due to intermolecular reaction with the alcoholic hydroxyl groups of the resin itself is preferred. will occur. When a monofunctional carboxylic acid or phenol is used in a blocking reaction, it is desirable to use a catalyst to prevent the intermolecular reaction from spreading. Otherwise, a useless toner powder with too high a melting point will be obtained. Catalysts suitable for the present toner powder production may be found in quaternary ammonium compounds. The catalyst of choice was found to be tetramethylammonium chloride. It has been found that the coloring materials necessary to make toner powders other than black toner powders are often not sufficiently soluble in many resins used to make toner powders. However, particularly good solubility is desired if the transparent toner powder required for multicolor copying processes is to be produced. It is considered an additional advantage of the toner powders of the present invention that many colored dyes are well soluble in the toner powders of the present invention. In order to obtain a two-component type developer, the toner powder of the invention is mixed with the desired carrier particles either immediately after its production or at a later stage. When the developer is used in magnetic brush development, iron particles, which may be provided with a surface coating, may be used as a carrier. The desired particle size of the carrier is known to those skilled in the art. Generally, its size is 50-150μm
It is. Depending on the particle size of the two components, the two-component developer typically contains 1-8% by weight of toner particles. The toner powders of the present invention are generally sufficiently cathodically charged when mixed with conventional carriers such as iron powders and iron oxide coated powders. If desired, a known cathode charge control agent may be added to obtain high cathode charge. The optimal cathode charging effect regulator is
It turned out to be Atlas Company's commercial product Atlac382E. Its active ingredient is 4,4'-isopropylidene-diphenol-propylene oxide-
It is fumarate. Acid value 10−20. Where an anodic charging toner powder is required, the toner powder of the present invention may be used in accordance with the Applicant's UK Patent Application No. 20005/77 of 12 May 1977 and 24 October 1977.
It may be mixed with the anodic charge control agent disclosed in Dutch Patent Application No. 7711623. Powders of anodically charged modified epoxy resin substrates of the type described above are not included in this application. Therefore, there is no complaint here. However, a two-component developer in which the toner powder of the present invention is anodically charged can be produced without adding a polarity adjusting agent to the toner powder of the present invention. This is accomplished by using a suitable carrier. Such carriers are known, for example, from British Patent Specifications No. 1251752, No. 1389744,
No. 1438973, No. 1342748, No. 1373000. When the toner powder of the present invention is used, for example, as a one-component developer, it is preferable to incorporate a magnetic substance as a colored substance into the resin in order to enable the toner powder to be used in a so-called magnetic brush development system. The system has been found to be optimal for use with one-component developers. Usually about 10-50% by weight of magnetizable material is required for this purpose. The invention is further illustrated in the following non-limiting examples. Example 1 In a hot melt apparatus, 4-
164 g of α,α-dimethylbenzylphenol, 526 g of Epicote 1001 (Shell), 0.3 g of tetramethylammonium chloride, and 60 g of carbon black (Printex G; Degussa) were mixed. While homogenizing, the temperature was raised to 200℃,
The condition was maintained for 60 minutes. The blocking reaction of the epoxy resin was completed at this stage and a toner low molecular weight fraction was obtained. Next, 250 g of phenoxy resin Ryuutapox 07-17 (Bakelite) was added as a high molecular weight fraction, and an additional 150 g of
The mixture was homogenized for a minute. After cooling to room temperature, the mixture was ground and graded. The particle size distribution of the produced toner powder was 6 to 30 μm, and its specific surface area was 0.42 μm ⁻¹ . The glass transition temperature (Tg) measured with a Dupont 990 Thermal Analyzer was 58°C. The epoxy value (EMM) was 9100, and the residual monofunctional phenol was 0.1% or less. Melt viscosity measured with a Rheometrics Inc. cone and plate mechanical spectrometer at a temperature of 140°C.
It was 210Nsm ^-2 . 3 parts by weight of this toner and iron oxide powder (Fer-mag)
MTM Brunito (Toniolo Italy) 97 parts by weight. This developer was stirred and charged in a developing unit. The toner obtained a charge of -19 μC/g. This developer was used to develop an anodic latent image on a selenium-type photoconductor. The image was electrically transferred onto a flat paper and fused by heat. Good copies were obtained. Extensive solid black areas on the base paper were reproduced with high and even copies without so-called edge effects. For testing purposes, the toner was heated in a thermal contact-melting device at a temperature of 68 to 114 °C (melting range 46 °C).
It took hold. Test melting device A4 with heating roller
It worked after 1.3 seconds of contact with copy paper. Example 2 A commercially available cathodically chargeable toner based on α-methylstyrene-butyl acrylate copolymer was
The test was conducted under exactly the same conditions as in Example 1. The glass transition temperature of this toner was 55°C. The toner has a temperature of 88-131℃ (melting range 43℃)
It was fixed on flat paper. The interval from T _g to the lower limit of the melting range of this toner was considerably wider than that of the toner obtained in Example 1. Example 3 350g Epicote 1001, 88g 4-α,α-
Dimethylbenzylphenol and as a catalyst
The method of Example 1 was repeated with the addition of 0.1 g of tetramethylammonium chloride. After 45 minutes, 0.1
An additional g of catalyst was added. After a reaction time of 90 minutes, a low molecular weight fraction was obtained. The residual amount of 4-α,α-dimethylbenzylphenol was 0.1% or less, and the EMM was 4470. This means that
This shows that about 88% of the epoxy groups are blocked. In the Z-blade mixer, Epicoat 1009
A high molecular weight fraction was obtained by reacting 455 g of (EMM=3000) with 34 g of 4,4'-isopropylidene diphenol. Tetramethylammonium chloride was used in a catalytic amount (0.2 g).
After a reaction time of 2 hours, 73 g of carbon black were added to the low molecular weight fraction thus obtained and mixed thoroughly. T _g is 67℃, EMM is
10900, the melt viscosity at 140°C was 1600 Nsm ^-2 . The toner powder obtained from this mixture was as follows: Example 1
It showed excellent electrostatic behavior similar to that of toner powder. The melting range was 82° to 135°C (width 53°C). Example 4 A low viscosity toner was produced by mixing and reacting 601 g of Epicote 1001, 151 g of 4-α,α-dimethylbenzylphenol, and 0.3 g of tetramethylammonium chloride at 150° C. for 90 minutes. 60 g of carbon black was added, followed by 188 g of 4,4'-isopropylidene diphenol-propylidene oxide fumarate polyester (Atlac 382E, Atlas Co.) having an acid value of 15. Mixing continued for 2 hours. T _g is 47℃, EMM is 8500,
The melt viscosity was 7 Nsm ^-2 at 140°C. This mixture was ground and graded. The obtained toner powder was treated with the iron oxide powder of Example 1 by triboelectrically.
It was cathodically charged to 27μc/g. The toner was easily fixed on the flat paper in a radiant heat device. Example 5 By applying the method of Example 1, Epikote 1001
(EMM=495) 48.9g, benzoic acid as modifier
A toner was prepared from 12.1 g of carbon black, 6 g of carbon black, and 33 g of phenoxy resin (Ryutapox 07.17). A thermally stable toner powder was obtained having the following properties. Melt viscosity (140℃) =
600Nsm ^-2 , T _g = 61°C, EMM = 35000, toner can be cathodically charged against commercially available iron carrier powder,
Moreover, it was well fixed by either radiation or contact heat. Example 6 A mixture of 450 g of Epicote 1004 (EMM=900), 111.2 g of P-toluenesulfonanilide as a modifier and 35.8 g of carbon black was blended at 200°C for 3 hours. T _g of this mixture = 72°C,
EMM=18000, melt viscosity (140℃)=85Nsm ^-2
It was hot. The produced toner powder was thermally stable and could be easily fixed onto paper by heat. Example 7 In a container equipped with a stirrer and an oil bath heater, 25.3 g
A mixture of Epicote 828, 21.7 g of 4-α,α-dimethylbenzylphenol, 0.5 g of tetramethylammonium chloride and 6.0 g of carbon black was heated to a temperature of approximately 180°C and held at this temperature for 90 minutes. . EMM of this reaction mixture
was 3800. 88% of the initial epoxy groups were reacted. Add Epicote 1009 (EM) to this reaction mixture.
M.=3150) 46.5g was added and stirred at a temperature of 200°C for 90 minutes. The melt was removed and cooled to room temperature. The obtained solid material was crushed and sieved by a known method to obtain toner powder having a particle size of 8 to 24 microns. This toner had a T _g of 51° C. and an EMM of 4100. Initial epoxy groups (starting Epicote 828 and
Approximately 82% of patients (out of 1,009) responded. The use of a liquid epoxy resin with an EMM value of 500 or less, preferably 250 or less, as a starting epoxy resin to produce a modified resin as shown in this example is disclosed in the applicant's Dutch patent application No.
Starting from a T _g of about 50° C. and a temperature slightly above the T _g without the need to add adjuvants such as N-cyclohexyl-P-toluenesulfamide as disclosed in No. 7415325. This method is extremely useful in that a toner powder having a melting range can be obtained. Adjuvants have a disadvantage in that they exhibit a tendency to leach out of the toner powder and deposit on the carrier particles and/or fuser rollers of the fuser device. That is,
The adjuvant has an undesirable effect on the charging characteristics of the toner powder and the durability of the fuser roller. When the above toner powder is used in an electrophotographic reproduction machine equipped with a contact fusing device with a roller coated with silicone rubber with a thin layer of silicone oil, the toner powder is heated to a temperature of 165
Very good fixing was achieved with an effective contact time of 0.03 seconds at .degree. At the same time interval as this time, styrene-butyl-
The temperature for fusing commercial toner powders based on acrylate copolymers was about 210°C.
This temperature is undesirable from the standpoint of external heat dissipation and energy conservation. When the toner powder of the present invention is used in large volume electrophotographic reproduction machines, it is highly advantageous to use a liquid epoxy resin as the starting material in the production of the toner powder.

Claims (1)

[Scope of Claims] 1. Finely divided toner particles containing an insulating thermoplastic resin and a colorant, wherein the insulating thermoplastic resin has at least 50% of its total epoxy groups blocked. 1 consisting mainly of modified resins that are derivatives of one or more epoxy resins, at least 5% of which is partially blocked by chemical reaction with monofunctional carboxylic acids, phenols or diarylsulfonamides, and It is partially blocked by an intermolecular reaction with the hydroxyl group of the epoxy resin or a reaction with a di- or polyfunctional epoxy curing agent, and has a melt viscosity of 2 to 200,000 Nsm ^-2 at 140°C and a glass transition temperature of 45 A heat-fusible toner powder for developing electrostatic latent images, characterized in that the temperature is between 85°C and 85°C,
However, the toner powder does not contain an anode charge control agent. 2. At least 20% by weight of the modified epoxy resin is a derivative of a liquid epoxy resin having a molecular weight of at most 500, and about 50-95% of the epoxy groups of the liquid epoxy resin are monofunctional carboxylic acids, phenols or diarylsulfonamides. The liquid epoxy resin is blocked by a chemical reaction, and about 5 to 50% of the epoxy groups of the liquid epoxy resin are blocked by an intermolecular reaction or a reaction with an epoxy curing agent. The toner powder according to item 1. 3. The toner powder according to claim 1 or 2, wherein the epoxy groups of the epoxy resin from which the modified epoxy resin is derived are blocked to such an extent that the overall epoxy value is at least about 8,000. . 4 The viscosity of toner powder at 140℃ is 2 to
1000 Nsm ^-2 and a Tg of 45 to 65° C. The toner powder according to any one of claims 1 to 3, which is particularly suitable for radiation melting. 5 At least of the epoxy groups of the starting epoxy resin
Toner powder according to claim 4, characterized in that 50%, preferably at least 70%, of the toner powder is blocked by monofunctional carboxylic acids, phenols or diarylsulfonamides. 6 The viscosity of toner powder at 140℃ is 200 to 200℃.
200000 Nsm ^-2 and a Tg of 45 to 85° C. The toner powder according to any one of claims 1 to 3, which is particularly suitable for fixing by contact melting. 7 At least of the epoxy groups of the starting epoxy resin
10-35% of the total epoxy groups are blocked by chemical reaction with monofunctional carboxylic acids, phenols or diarylsulfonamides, while at least
Toner powder according to claim 6, characterized in that up to 50% of the remaining epoxy groups are blocked by intermolecular reaction with the alcoholic hydroxyl groups of the epoxy resin. 8. at least 40-75% of the total number of initial epoxy groups of the starting epoxy resin are blocked mostly by chemical reaction with monofunctional carboxylic acids, phenols or diarylsulfonamides and only to a small extent by intermolecular reactions; Approximately 25~ of the epoxy group
7. The toner powder according to claim 6, wherein 60% of the toner powder is blocked by reaction with an epoxy hardener. 9. The toner powder according to any one of claims 1 to 8, characterized in that optionally substituted benzoic acid is used in the blocking step. 10 In the blocking step, phenols and phenols substituted with one or more alkyl, aralkyl, cycloalkyl, aryl, alkylaryl, alkoxy or aryloxy groups and which are substantially non-volatile under the blocking reaction conditions. The toner powder according to any one of claims 1 to 8, characterized in that: is used. 11. Toner powder according to claim 10, characterized in that 4-(α,α-dimethylbenzyl)-phenol is used in the blocking step. 9. The toner powder according to claim 1, wherein 12 p-toluene-sulfonanilide is used in the blocking step. 13. Claims 1, 2 or 8, characterized in that 4,4'-iso-propylidene-diphenol is used as the epoxy curing agent.
The toner powder described in any of the paragraphs. 14. Block or at least partially block the starting epoxy resin or mixture of starting epoxy resins and
finely divided toner particles containing an insulating thermoplastic resin and a coloring substance, characterized in that the starting epoxy resin or the mixture of starting epoxy resins in the molten state at a temperature of 250° C. is homogenized with the coloring substance. and the insulating thermoplastic resin is primarily composed of a modified resin that is a derivative of one or more epoxy resins in which at least 50% of the total epoxy groups are blocked, of which at least 5% are blocked. Partially blocked by chemical reaction with monofunctional carboxylic acids, phenols or diarylsulfonamides, and partially blocked by intermolecular reaction with the hydroxyl groups of the epoxy resin or reaction with di- or polyfunctional epoxy curing agents. It is blocked and the melt viscosity is 2 to 2 at 140℃.
200000Nsm ^-2 , and the glass transition temperature is 45 to 45.
1. A method for producing a heat-meltable toner powder for developing electrostatic latent images, characterized in that the temperature is 85° C., which does not contain an anode charge control agent. 15. Process according to claim 14, characterized in that a catalytic amount of a quaternary ammonium compound, in particular tetramethylammonium chloride, is used during the blocking step.