DE2305739C3 - Electrostatographic magnetic toner - Google Patents

Description

The Erfindun "refers to an e! Ektroststo ^a ra ⁿ Hischi? N of the magnetic toner particularly for Magnetbür sten development in an electrostatographic Recording method is suitable, as well as a method for its production.

The basic electrostographic recording process is described in US Pat. No. 2,297,691. It becomes a uniform electrostatic Charge is applied to a photoconductive, insulating layer and this layer is exposed imagewise A discharge takes place on the exposed parts of the surface and the result is electrostatic latent image is developed by using a toner made from a finely divided electroscopic material Applies The toner adheres to the areas of the latent image on which a charge is retained so that a toner image corresponding to the electrostatic latent image is formed. This toner image can transfer to an image receiving material such as paper and become permanent on it when exposed to heat be fixed. It is necessary that the toner is softened or melted in the heat so that the toner is melted on the image receiving material. It is also possible to have an electrostatic latent image to be obtained by immediately charging the layer imagewise

There are several methods of applying toners to an electrostatic latent image which A known procedure is described in US Pat. No. 26 IC 552 and is referred to as cascade development. In this process, a developer material is selected relatively large carrier particles with an electrostatically applied coating of finely divided toner particles conveyed to the surface carrying the electrostatic latent image and rolled or Moved in a cascade. The toner particles are attached to the charged portion of the latent image. Of the Carrier and the excess toner are recycled. This method is very good for development suitable for line art.

In the older patent application DE-OS 22 61 969.8, an electrostatographic toner is proposed with a particle size of 0.5 to 1000 μm and a caking temperature of at least 37.8 ° C, encapsulated in a polymeric shell material, a colorant and an adhesive polymer Core material with a viscosity of 5 χ 10 ⁴ to 10 ⁸ poise at a shear rate of 75 see- 'and the temperature of the pressure fixing device used and a freezing temperature below or not more than a few degrees above the temperature to which the toner image formed from the toner material is heated and optionally contains finely powdered hydrophobic silicon dioxide.

The toner material according to the earlier patent application is particularly suitable for high-speed copying machines. The toner material according to the earlier patent application shows a high resistance to mechanical effects, such as impact, friction and wear and tear Abrasion, does not tend to smear and agglomerate and is already at low electrostatic Initial surface potentials effective.

Another development method, the so-called magnetic brush method is known from US-PS 28 74 063 is known In this method uses an apparatus which usually comprises a non-magnetic, rotatably mounted cylinder, which jm interior of the Z ^v! Inders fixed magnetic means mounted has. The cylinder becomes rotating

arranged so that part of the surface into one The source of the developer mixture is immersed or otherwise in contact with it. The granular mass that the developer mixture is magnetically attracted to the surface of the cylinder. If that Developer mixture comes into the influence of the field created by the magnetic devices in the When a cylinder is formed, the particles arrange themselves in brush-like formations. The brush-like Formations of the developer mix tend to coincide with the lines of magnetic flux stand upright in the vicinity of the poles and lie essentially flat when the developer mixture is outside the vicinity of the magnetic Pole is at one revolution, the continuously rotating cylinder picks up developer from a supply source and feeds some of this material or that return all material to the supply source. This operating mode ensures that there is always a fresh one Developer for the image surface at the point of contact with the magnetic brush is available In In a typical cycle of revolution, the cylinder performs the successive stages of receiving the Developer mixture, brush formation, brush contact with the photoconductive element and the No release of the developer mix.

During the magnetic brush development of the electrostatic latent images, the developer mix is in the generally a triboelectric mixture of a fine toner powder of a colored or pigmented one thermoplastic resin with larger carrier particles of a soft magnetic material such as iron filings or reduced iron oxide particles. The relative high density of iron and the other similar ferromagnetic carrier materials can be a disadvantage, since an undesirable retention of the carrier particles on the photoconductor surface, an excess Abrasion of the recyclable photoconductive layers and other machine parts are caused can, which leads to a reduction in the image quality of the copies produced. In addition, they are very high dielectric constants observed in developers made of solid iron support particles at certain approaches Edge developments are a disadvantage.

Magnetically responsive electrostatographic toners are, inter alia, from DE-AS 19 37 651 and the DE-OS 20 05 932 known According to DE-AS 19 37 651 the toner material consists of spherical particles, from a thermoplastic material, in their Surface the electrically conductive particles are almost completely embedded. In the thermoplastic Magnetically responsive particles can also be embedded in the material. According to DE-OS 20 05 932 the toner particles consist of tiny glass spheres coated with a magnetic layer. Such magnetic toners are not suitable for being pressure-fixed on an image receiving material.

The object of the invention is to provide an electrostatographic device that can be fixed by pressure and / or heat To provide toner according to the earlier patent application P 22 61 969 available, which is suitable for a magnetic brush development

The invention is defined in the claims.

The adhesive polymeric core material containing a colorant and magnetic particles is in encapsulated a polymeric shell material, which

Has the desired electrostatographic properties The toner is exposed to a magnetic field can be influenced and has good electrostatographic properties due to the polymeric shell materials used. He can be on a suitable Image receiving material are pressure-fixed, the fixed image being attached by means of the adhesive core material adhered to the image receiving material The toner can be used in a magnetic brush developer system without the additions of a carrier. The toner can be coronary loaded while under the influence of the magnetic field and before entering the Developer zone. The resulting charged toner particles have excellent developing properties and give good fixed copies. That on A toner image formed on a recording material can be transferred to an image receiving material made of paper and pressure-fixed there by providing a pressure roller against the paper, which is soft in In addition, there is intimate contact with the recording material and the developed image the toner image on the recording material in contact with an image receiving material made of paper are brought, which is pressed by a pressure roller in contact with the toner image, whereby the The toner image is transferred to the paper and fixed there by pressure. It has been shown that this method is more effective and that the toner image is completely transferred, thereby reducing the amount of cleaning required for the recording material will.

Suitable polymeric shell materials generally have a viscosity which is higher than that of the polymeric core materials. They are usually materials that do not flow at the moderate pressures and temperatures likely to occur during storage. Thus, for the toner of the present invention amorphous shell materials having a glass transition temperature of 50 ⁰ C and crystal coating materials having a melting point above 40 ° C from above.

If the shell material exhibits more than one glass transition temperature or melting point, then it generally has at least a glass transition temperature above 50 ° C. or a melting point above 40 ° C, the other glass transition temperature or the other melting point being above or can be below these temperatures. It is generally preferable for the shell materials that these are brittle and somewhat fragile, as these properties allow easy and complete breaking allow the toner shell, thereby releasing the adhesive core materials. For some For purposes of application, however, it is preferable to use shell materials that are tough and less brittle under the fixation conditions. That is, that Shell material may have a slight effect at the pressures applied at the fixation temperatures Show flow. This type of polymeric shell materials is particularly useful when for fixing the Both heat and pressure are used in the toner image. Suitable shell materials include a lot wide range of rheological properties, as variations in the properties of the casing material increase can be compensated to a large extent by adjusting the envelope thicknesses. About that In addition, the properties of suitable shell materials depend on the properties of the

sealed polymeric core materials. Thus, the combination of the elastic modulus of the shell material and the shell strength is adjusted to compensate for the viscosity of the polymeric core materials used, so that the shell ruptures if it is brittle or ruptures under the fixation conditions of the applied temperature and pressure is ductile Thus, cover materials with a modulus of elasticity of above 7.03 kg / cm ² and a compressive strength of above 35.2 kg / cm ^{2 give} satisfactory results. However, shell materials with a modulus of elasticity of above 70.3 kg / cm ² and a compressive strength of above 141 kg / cm ^{2 are} preferred because the resulting toner particles have improved fixing properties and are not destroyed on impact. Preferred shell materials are polystyrene, polycarbonates and the reaction products of dimer acids with linear diamines.

It has been found that there is a relationship between the glass transition temperature (Tg) of the polymer core material and the pressure fixability of the magnetic toners according to this invention. That is, the fixability of these toners is generally improved as the Tg of the polymer core material decreases

Furthermore, there is also a connection between the 7 £ value of the polymeric shell material and the caking temperature. If the ratio of the polymeric core material to the shell material jo is approximately 1: 1, then the caking temperature of the toner corresponds approximately to the Tg value of the shell material higher strength of the shell material for a given shell material, such as polystyrene, results in a stronger, ie, less easily crushable, toner. There is also evidence that a higher ratio of polymeric core material to shell material gives better fixation properties, but the effect on the toner crushability is indeterminate. It appears that toner crushability and fixation are affected in the same way, but to different degrees, by changes in the shell and polymer core materials, as well as in the core / shell ratio.

If, for a similar core material, a low molecular weight polystyrene is changed to a shell material made of polystyrenes with a higher molecular weight, or if the ratio of core and shell material is reduced to 1: 1, the fixability generally decreases, but not to the extent that the breaking strength increases measurements of the breaking strength of toners with flowable core agree well with the assumption that between breaking strength and caking a direct relationship exists in a toner with a shell of polystyrene of high molecular weight makes it a caking ability determined which is about half the size _b o as that which has a low molecular weight polystyrene shell with similar core material while the fixability is essentially the same.

Suitable polymeric materials for the core druckfi- ^ xierbaren magnetic toner of the invention are for example polyesters, urethane polymers, polyester-based, epoxidized phenol-formaldehyde resin, polyI sobutylene, polyamides, such as the reaction products of dimerized linoleic acid with diamines or polyamines and the reaction products of dimeric acids with linear diamines, 50/50 or 45/55 docosyl acrylate / Styrene copolymers, materials that exhibit a shear thinning viscosity behavior due to intermolecular hydrogen bonds, such as reaction products of anhydrides and hydroxy compounds, e.g. B. Trimellitate ester of polycaprolactam with two terminal hydroxyl groups, polyurethane elastomers, polyester-based acrylic resins, rosin esters and modified rosin esters, polyvinyl acetate, polymeric reaction products of isopropylidene diphenoxypropanol and adipic acid, polymeric reaction products of isopropylidene diphenoxypropanol and sebacic acid, CM-diurea and mixtures thereof.

The shell material can be a homopolymer or a copolymer of two or more monomers be. Examples of typical skin materials are polystyrenes, polymonochlorostyrene, copolymers, such as Styrene / methacrylates and styrene / acrylates, polycarbonates, e.g. B. poly (4,4'-dioxydiphenyl-2 £ 'propane carbonate, Polyethers, low molecular weight polyethylene, polyesters, such as polymeric acrylic and methacrylic esters, Fumarate polyester resins, polyamides, such as reaction products of terephthalic acid and alkyl-substituted ones Hexamethylendiamine ^ the reaction products of dimerized linoleic acid with diamines or polyamines, the reaction products of dimeric acids with linear diamines, naturally occurring materials such as gelatin, glue or gum arabic, as well their mixtures.

In the manufacture of the electrostatographic magnetic toners according to the invention Shell materials are preferred which contain a relatively high percentage of a styrene resin. That Styrene resin can be a homopolymer of styrene or styrene homologues or a copolymer of styrene with other monomers that have a single methylene group attached to a carbon atom contain a double bond. Thus, typical monomer materials which can be «» polymerized by addition polymerization with styrene are: p-chlorostyrene, vinylnaphthalene, ethylenically unsaturated Monoolefins, such as ethylene, propylene, butylene or isobutylene, vinyl esters, such as vinyl acetate, vinyl propionate, Vinyl benzoate or vinyl butyrate esters of methylene aliphatic monocarboxylic acids, such as methyl acrylate, Ethyl acrylate Isobutyl acrylate Dodecyl acrylate, n-octyl acrylate 2-chloroethyl acrylate Phenyl acrylate, methyl chloroacrylate, methyl methacrylate, ethyl methacrylate Propyl methacrylate isopropyl methacrylate or butyl methacrylate acrylonitrile, methacrylonitrile, acrylamide, Vinyl ethers, such as vinyl methyl ether, vinyl isobutyl ether or vinyl ethyl ether, vinyl ketones, such as vinyl methyl ketone, vinyl hexyl ketone or methyl isopropyl ketone, Vinylidene halides such as vinylidene chloride or vinylidene chlorofluoride and N-vinyl compounds such as N-vinyipyrrole, N-vinylcarbazole, N-vinylindole or N-vinylpyrrolidone and mixtures thereof. The styrene resins can can also be formed by polymerizing mixtures of two or more of these unsaturated monomeric materials with a styrene monomer.

The shell material of the toner has a caking temperature of at least 3/8 ⁰ C. In caking temperatures less than 37.8 ° C to the toner particles tend, during storage and operation of the machine to agglomerate and

on the surface of the reusable recording materials to form unwanted films that degrade image quality.

The ratio of polymers! Shell material to polymeric core material can be any suitable value ocin. In general, it varies with the ones you want Properties with regard to the strength, the strength, the porosity and the solubility of the shell. Thus, in the generally the ratio of shell material to core material between 99 parts by weight of shell material on! Part by weight of core material and 1 part by weight of shell material to 99 parts by weight of core material lie. However, the preferred range between a ratio of 7 parts by weight is Hüiienmaieriai to 1 part by weight of core material and 1 part by weight to 7 parts by weight of core material, as in this case Toner particles with the best surface properties can be obtained.

The amount of the colorant is generally 1 to 25% by weight, in particular 3 to 20% by weight, of des Toners. In this way, the resulting toner forms a clearly visible image on the image receiving material.

Pigments and / or dyes that can be used in the present invention are the same as that can be used for known electrostatographic toners. Soot is only used here as a black pigment, for example called.

Since the toner particles are generally formed in sizes from 0.5 to 35 μm, the pigment should preferably have a diameter of less than 0.1 μm. If possible, it should be even smaller there this contributes to the uniformity of the color of the end product. In any case, the diameter of the Pigment particles or the other insoluble material be less than 75% by volume of the average core diameter.

Examples of typical magnetic and magnetizable materials are metals such as cobalt, iron, and nickel and metallic alloys and mixtures of metals such as aluminum, cobalt, copper, iron, lead, Magnesium, nickel, tin, zinc, gold, silver, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, Titanium, tungsten, vanadium, zirconium, metal compounds including metal oxides such as aluminum oxide, Iron oxide, oxidized steel, nickel oxide, zinc oxide, zirconium oxide, Titanium oxide and magnesium oxide, refractory nitrides such as vanadium nitride and chromium nitride, carbides, such as tungsten carbide and silicon carbide and ferromagnetic ferrites and their mixtures. The magnetic or magnetizable component should be a material that reacts to a magnetic field with low or high Frequency responds. Furthermore, the magnetic or magnetizable component should be finely divided and preferably in submicron dimensions as this allows for rapid dispersion during manufacture the toner of the present invention enables and enables it to be a part of the encapsulated core will. Preferably the magnetic or magnetizable particles have a particle size between 0.1 μΐη and 1 µm. Good results are obtained if the magnetic or magnetizable particles in an amount of between 1% and 50% by weight, based on the weight of the toner particles Preferably the magnetic or magnetizable component should be in an amount between 5 and 20 % By weight, based on the weight of the toner particles, be present, since in this case optimal results can be obtained.

The production of the toner according to the invention can be carried out according to US Pat. No. 3,338,991, 33,26,848 and 35 02 582 are carried out. A preferred manufacturing method solves this

^The adhesive polymeric core material and the polymeric shell material dissolve in a solvent, dissolve or disperse the colorant in the solution and disperse the magnetic or magnetizable particles therein. Then the solvent will last so long

ι «removed until at least part of the colorant, part of the polymeric core material and part of the magnetic or magnetizable particles separate out of the solution. The solution then becomes like this long further solvent removed until the

i "polymeric shell material around the coloring material that polymeric core material and the magnetic or magnetizable particles around it.

The invention is illustrated in the examples. All parts therein are based on weight.

The term »adhesive point« used means the temperature at which a material adheres to one metallic carrier adheres For example, a continuous series of samples is on for about 2 hours balanced with a Kofler heating bank and then carefully brushed away Lowest temperature at which the sample adheres to the metal plate of the heating bench. The designation "Caking attempt" refers to attempts which are usually carried out on small open dishes with the Toner material can be made at specific temperature conditions. The caking temperature is the lowest temperature at which the toner is exposed for an equilibrium period and the crusty mass formed no longer easily crumbles into the original particles can be. The term "geometric standard deviation" is the deviation that occurs in the Particle size analysis occurs, measured roughly as the ratio of particle diameter greater than 84% of the sample, to the particle diameter greater than 50% of the sample. The expression "Taber Cycles" indicates the resistance of a fixed toner image to abrasion with a Taber abrasive device at. A standard test pattern is copied under conditions to an integrated optical Form density as determined by a densitometer to be 1.2 ± 0.1. The test pattern is pressure-fixed and then with a weight of 375 g rubbed on the abrasion arm until the measured density is 80% of

so the initial density is The result is expressed as the number of Taber cycles required to reduce the initial density by 20%.

Comparative experiment

A magnetic control toner blend is prepared containing 5 parts by weight of carbon black, 15 parts by weight magnetic iron oxide particles and 80 parts by weight of a polymeric condensation product of 2 ^ - to (4-

bo hydroxyisopropoxyphenyl) propane and fumaric acid This polymer has a number average molecular weight of 8,000. When melted and premixing, the mass is placed in a rolling mill and thoroughly ground. It will be a uniformly dispersed mass of carbon black and iron oxide particles was obtained in the thermoplastic resin body. The resulting blended composition is cooled and then fine-tuned in a nozzle pulverizer

divided, whereby toner particles with an average particle size of 7 to 12 μ; η are obtained. In a modified magnetic brush developer in which the fuser has been removed, copies are made to give an integrated optical density of 1.2 ± 0.1. The pressure fixation takes place in a device which has two steel rollers with a diameter of 7.6 cm each, which are in contact with one another. The contact pressure between the two rollers can be varied ^{as desired up to 90 kgf / cm 2.} The upper steel roller can be heated externally with a 2000 watt quartz infrared lamp. The temperature of the melting device is regulated with a proportional temperature controller and monitored by means of a thermistor in sliding contact with the center of the upper melting roller. The copies are then ^{pressure-fixed at 53.6 or 71.5 kg / cm 2} , which is carried out with the aid of heat at temperatures between 43.3 and 60.0 ° C. in increments of 6 "C. After passing through the Melting device, the copies are examined for the degree of fixation, expressed in Taber cycles. The results of these examinations are summarized in the following table:

Fixation (taber cycles)

Temperature, ⁰ C contact pressure,
kp / cm ²

53.6 71.5

43.3 1.0 2.0
48.9 1.0 2.0

54.4 1.5 2.0
60.0 2.0 3.5

machine used. If the test conditions are essentially identical, the following degree of fixation is expressed in Taber cycles, get:

Fixation (taber cycles)

2 «

25th

S (I

example 1

An inventive magnetic toner is from w a solution prepared containing 300 g of a polystyrene and 300 g of polyhexamethylene sebacate having a weight average molecular weight of about 24,000 in a mixture of cyclohexane and chloroform in a volume ratio of cyclohexane: chloroform of 4.0: 1.0 includes Carbon black and magnetic iron oxide particles are dispersed in the solution by vigorous stirring. The final concentrations are 2.4% polystyrene, 2.4% polyhexamethylene sebacate, 0.2% carbon black, 1.0% iron oxide and 94.0% solvent. The solution with the dispersed carbon black and iron oxide is spray-dried using a spray dryer with a spinning disc atomizer which operates at a rotational speed of 30,000 rpm and a feed rate of 200 ml per minute. The inlet temperature of the drying air is 54.4 ° C and the outlet temperature of Dry air 383 ° C. The dry product obtained is a toner with a volume-average particle size corresponding to a diameter of ω> 153 μ with a geometric standard deviation of 2.17. The point of adhesion, the caking and examination of the crushed particles with a scanning electron microscope indicate that the shell consists mainly of polystyrene and the core consists mainly of polyhexamethylene sebacate, carbon black and iron oxide. ⁰ C contact pressure,
kp / cm ²

53.6 71.5

43.3
48.9

4.2
5.5

5.0
6.0

From the above results, it can be seen that this toner is substantially the same Fixing pressures and temperatures has a higher degree of fixation than the control toner mixture of the Comparative experiment.

Example 2

A magnetic toner material is made from a solution comprising 900 g of a polystyrene and 900 g of the reaction product of isopropylidenediphenoxypropanol and sebacic acid with a number average Molecular weight of 2230 in a mixture of heptane and chloroform with a volume ratio of heptane: chloroform = 1.3: 1.0 The core-to-wall ratio is 1: 1. In carbon black and magnetic iron oxide particles are dispersed in the solution by vigorous stirring. The final concentrations are 2.4% polystyrene, 2.4% reaction product of isopropylidenediphenoxypropanol and sebacic acid, 0.2% carbon black, 1.0% iron oxide and 94.0% solvent. The solution with the dispersed carbon black and iron oxide is made using the described spray dryer at 50,000 rpm and a load speed spray-dried from 200 ml / min. The inlet temperature of the drying air is 71.1 ° C and the outlet temperature of the air is 51.7 ° C. The dry product is a volume average toner Particle size corresponding to a diameter of 16.7 μm with a geometric standard deviation of 1.67. The sticking point, the caking and the examination of the crushed Particles with a scanning electron microscope suggest that the shell is primarily made of polystyrene and the core consists mainly of the reaction product of isopropylidenediphenoxypropanol and The toner particles are made up of sebacic acid, carbon black and iron oxide in place of the developer Test device according to the comparative experiment used with essentially identical test conditions the following degree of fixation, expressed in Tabercykia, is obtained.

Fixation (taber cycles)

Temperature, ° C

Contact pressure,

kp / cm ²

53.6 71.5

433
48.9

4.5
4.5

6.0
10.0

From the above results, it can be seen that this toner is substantially the same Fixation pressures and temperatures has a degree of fixation that is greater than that of the control toner

It

mixture of the comparative experiment. In addition, this toner was found to be fixed at 23.9 ° C gave the same degree of fixation as the control composition of the comparative experiment, which in 48.9 ° C and corresponding pressures was fixed.

Example 3

A magnetic toner is formed from a solution containing 647 g of a polystyrene and 647 g Polyäthylenacelat having a melting point between 40 ⁰ C and 50 ° C in a mixture of cyclohexane and chloroform in a volume ratio of cyclohexane: chloroform of 2.0: 1.0 contains. Carbon black and nickel particles are dispersed in the solution by vigorous stirring. The final concentrations are 2.4% polystyrene, 2.4% polyethylene acelate, 0.2% carbon black, 0.9% nickel and 94.1% solvent. The solution with the dispersed carbon black and the nickel is spray-dried using a spray dryer of the type described, but with a diameter of 1.52 m at 21,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the drying air is 57, ⁰ ° C, the outlet temperature of the air is 43.3 ⁰ C. The dry product, a toner having a volume average particle size corresponding to a diameter of 17.8 μπι with a geometric standard deviation of 1.74. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly made of polystyrene and that the core is mainly made of polyethylene acelate, carbon black and nickel. The toner particles are used instead of the developer in the test device according to the comparative experiment. With essentially identical test conditions, the following degree of fixation, expressed as Taber cycles, is obtained.

Fixation (taber cycles)

Temperature, ° C Contact pressure, kgf / cm ² 53.6

71.5

43.3 36.6 34.0

48.9 37.3 38.6

Example 4

A magnetic toner is prepared from a solution containing 43 kg of polystyrene and 43 kg of the reaction product of isopropylidenediphenoxypropanol and adipic acid having a number average molecular weight of 3,100 in a mixture of chloroform and heptane in a volume ratio of chloroform: heptane of 1: 13 in the solution carbon black particles and magnetic copper alloy particles are dispersed by vigorous stirring. The final concentrations are 4.75% polystyrene, 4.75% of the reaction product of isopropylidenediphenoxypropanol and adipic acid, 0.5% carbon black, 1.0% copper alloy particles, and 89.0% solvent. The solution with the dispersed carbon black and the copper alloy particles is spray-dried using the spray dryer of the above example at a rotation speed of 21,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the drying air is 98.9 ° C and the outlet temperature of the air is 71, 1 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 12.7 μm with a geometric standard deviation of 1.58. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly made of polystyrene and that the core

ίο mainly from the reaction product of isopropylidenediphenoxypropanol and adipic acid, carbon black and the copper alloy particles. The toner particles are used in place of the developer in the test machine of Example 1. At essentially identical test conditions, except that the copies were made without the aid of heat are pressure-fixed, it is found that the degree of fixation

2.0 Taber cycles at a pressure of 53.6 kgf / cm ² and 3.8 at a pressure of 71.5 kgf / cm ² .

Example 5

A magnetic toner is made from a solution containing 300 g of a polystyrene and 300 g of one epoxidized phenol-formaldehyde resin with a number average molecular weight of 700 in a mixture of chloroform and cyclohexane at a volume ratio of chloroform: cyclohexane of 1.0: 0.75 contains in the solution soot particles and particles of a

jo magnetic aluminum-nickel-cobalt alloy dispersed. The final concentrations are 4.75% polystyrene, 4.75% epoxidized phenol formaldehyde, 03% Carbon black, 1.0% aluminum-nickel-cobalt alloy, and 89.0% solvent. The solution with the dispersed

r, carbon black and the aluminum-nickel-cobalt alloy particles are spray-dried using the described spray dryer with a diameter of 1.52 m at a speed of 21,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the drying air is 68.3 ° C and the outlet temperature of the air is 52.8 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 13.0 μm with a geometric standard deviation of 1.61. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly made of polystyrene and that the core is mainly made of epoxidized phenol-formaldehyde, carbon black and aluminum-nickel-cobalt alloy particles Developer used in the test device of the comparative experiment. Under essentially identical test conditions, with the exception that the copies are pressure-fixed without the aid of heat, it is found that the degree of fixation at a pressure of 53.6 kgf / cm ^{2 is} approximately

3.1 Taber cycles and at a pressure of 713 kp / cm ^{2 is} approximately 5.8 Taber cycles

Example 6

A magnetic toner is made from a solution containing 400 grams of fractionated polystyrene and 400 grams of the reaction product of isopropylidenediphenoxyb5 propanol and adipic acid with a number average Molecular weight of 2100 in a mixture of chloroform and heptane with a volume ratio of chloroform: heptane of 1:13

contains soot particles and magnetic cobalt particles are dispersed in the solution by vigorous stirring. The final concentrations are 4.75% polystyrene, 4.75% of the reaction product of isopropylidenediphenoxypropanol and adipic acid, 0.5% carbon black, 1.0% cobalt and 89.0% solvent. The solution with the dispersed kiss and the cobalt particles is spray-dried using a spray dryer of the type described with a diameter of 76.2 cm at a speed of rotation of 50,000 lpm and a feed rate of 200 ml / min. The Eir.iaDtsmperatur the dry air is 93.3 ° C, the outlet temperature of the air 76.7 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 12.6 μm with a geometric standard deviation of 1.87. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly made of polystyrene and that the core is mainly the reaction product of isopropylidenediphenoxypropanol and adipic acid, carbon black and cobalt. The toner particles are used in place of the developer in the test device of the comparative experiment. Under essentially identical test conditions with the exception that the copies are fixed without the aid of heat, a ^{degree of fixation of 1.5 Taber cycles is obtained at a pressure of 53.6 kg / cm 2} and at a pressure of 71.5 kg / cm ^{2 out} of 3.2 Taber cycles obtained.

Example 7

A magnetic toner is prepared from a solution containing 363 g of a polystyrene and 437 g of epoxidized phenol-formaldehyde with a number average molecular weight of 700 in a mixture of chloroform and cyclohexane in a chloroform: cyclohexane volume ratio of 4: 3 magnetic nickel-copper-cobalt alloy dispersed by vigorous stirring. The final concentrations are 43% polystyrene, 5.2% epoxidized phenol-formaldehyde, 0.5% carbon black, 1.1% nickel-copper-cobalt alloy, and 88.9% solvent. The dispersed carbon black and nickel-copper-cobalt alloy solution is spray-dried using the spray dryer of the previous example at a rotational speed of 50,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the drying air is 62.8 ° C The outlet temperature of the air is 51.7 ° C. The dry product is a toner with a volume average size corresponding to a diameter of 15.0 μm with a geometric standard deviation of 1.53. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly made of polystyrene and that the core is mainly made of epoxidized phenol-formaldehyde, carbon black and the nickel-copper-cobalt alloy that the toner particles are in place of the developer used in the test device of the comparative experiment. Under essentially identical test conditions with the exception that the copies are pressure-fixed without the aid of heat, a degree of fixation at a pressure of 53.6 kgf / cm ² of 3.2 Taber cycles and at a Print of

.1.5 kgf / cm ^{2 obtained} from 6.2 Taber cycles.

Example! 8th

^r , A magnetic toner is prepared from a solution containing 400 g of a polystyrene and 400 g of the reaction product of isopropylidenediphenoxypropanol and sebacic acid having a number average molecular weight of 2230 in a mixture of

ίο chloroform and cyclohexane at a volume ratio Chloroform: contains cyclohexane of 1: 3. As a result of vigorous stirring, particles of soot and magnetic platinum-cobalt alloy particles dispersed Final concentrations are 4.75% polystyrene, 4.75% of the reaction product of isopropylidenediphenoxypropanol and sebacic acid, 0.5% carbon black, 1.1% Platinum-Cobalt Alloy and 88.9% Solvent. the Solution with the dispersed carbon black and the platinum-cobalt alloy is made using a spray dryer of the type described with a diameter of 1.52 m at a speed of 21,000 Rpm and a feed rate of 200 ml / min. Spray-dried. The inlet temperature of the Dry air is 62.8 ° C and the outlet temperature of the air is 48.9 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 13.3 μm with a geometric standard deviation of 1.75. The sticking point, the caking and the examination

jo ching of the crushed particles with the scanning electron microscope suggest that the shell is mainly made of polystyrene and that the core mainly from the reaction product of isopropylidenediphenoxypropanol and sebacic acid, carbon black and Platinum-cobalt alloy consists of the toner particles in place of the developer in the test device of Example 1 used under essentially identical test conditions except that the copies are pressure-fixed without the aid of heat, becomes a fixing degree at a pressure of

53.6 kp / cm ^{2 obtained} from 27 Taber cycles and at a pressure of 71.5 kp / cm ³ from 86 Taber cycles.

Example 9

A magnetic toner is made from a solution containing 300 g of a polystyrene and 300 g of des Reaction product of isopropylidenediphenoxypropanol and adipic acid with a number average Molecular weight of 1780 in a mixture of

so chloroform and heptane at a volume ratio of chloroform: heptane of 1: 1.3 contains In the Solution are dispersed by vigorous stirring soot particles and nickel oxide particles. The final concentrations are 2.4% polystyrene, 2.4% of the reaction products of Isopropylidenediphenoxypropanol and adipic acid, 0.2% carbon black, 0.8% nickel oxide and 94.2% solvent. The solution is mixed with the dispersed carbon black and nickel oxide using the spray dryer of the above example at a rotational speed of 21,000 rpm and a feed speed spray-dried at 200 ml / min. The inlet temperature of the drying air is between 71.1 and 61.7 ° C. The outlet temperature of the air is between 51.7 and 46.1 ° C. The dry product is a Toner having a volume average particle size corresponding to a diameter of 15.1 µm with a geometric standard deviation of 1.66. The sticking point, the caking and the under-

breaking the crushed particles with a
electron microscope indicate that the shell consists mainly of polystyrene and that the core consists mainly of the reaction product of isopropylidenediphenoxypropanol and adipic acid, carbon black and nickel oxide Except that the copies are pressure-fixed with the aid of heat, a degree of ^{fixation of 1.5 Taber cycles becomes at a pressure of 53.6 kg / cm 2 and} a degree of fixation of 3.4 with a pressure of 71.5 kg / cm ² Taber cycles received.

Example 10

A magnetic toner is prepared from a solution containing 250 g of a polystyrene and about 500 g of the reaction product of isopropylidenediphenoxypropanol and adipic acid having a number average molecular weight of 1780 in a mixture of chloroform and heptane at a volume ratio of chloroform: heptane of 1: 1.3 . Vigorous stirring disperses soot particles and magnetic nickel-zinc alloy particles in the solution. The final concentrations are 1.6% polystyrene, 3.2% of the reaction product of isopropylidenediphenoxypropanol and adipic acid, 0.2% carbon black, 1.0% nickel-zinc Alloys and 94.0% solvents. The solution with the dispersed carbon black and the nickel-zinc alloy is carried out using a spray drier of the above example at a rotational speed of 21,000 rpm and a feed rate of 200 ml / min spray-dried the inlet temperature of the drying air is 61.1 ⁰ C and the outlet temperature the air 45.0 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 12.3 μm with a geometric standard deviation of 1.58. The point of sticking, caking and examination of the crushed particles with a scanning electron microscope all indicate that the shell is mainly composed of polystyrene and that the core is composed mainly of the reaction product of isopropylidenediphenoxypropanol and adipic acid, carbon black and nickel-zinc alloy. The toner particles are used in place of the developer in the test device of the comparative example. Under essentially identical test conditions except that the copies are pressure-fixed without the aid of heat, a degree of ^{fixation of 4.4 Taber cycles is obtained at a pressure of 53.6 kg / cm 2} and at a pressure of 71.5 kg / cm ^{2 obtained} a degree of fixation of 9.7 Taber cycles.

Example 11

A magnetic toner is made from a solution containing 200 g of the reaction product of a dimer acid with a linear diamine and 200 g of the reaction product of isopropylidenediphenoxypropanol and adipic acid having a number average molecular weight of 1780 in a mixture of Contains chloroform and isopropanol at a volume ratio of chloroform: isopropanol of 1: 2. In of the solution, soot particles and oxidized steel particles are dispersed by vigorous stirring. The final concentrations are 4.8% of the reaction product of the dimeric acid with a linear diamine, 4.8% of the reaction

product of isopropylidenediphenoxyprcpanol and adipic acid, 0.5% carbon black, 13% oxidized steel and 88.5% Solvent The solution with the dispersed carbon black and the oxidized steel is prepared using a > Spray dryer of the type described with a diameter of 76.2 cm at one speed spray dried at 50,000 rpm and a feed rate of 200 ml / min. The inlet temperature the dry air is 66.1 ° C and the outlet

Hi temperature of the air 47.8 ⁰ C. The dry product is a toner of a volume average particle size corresponding to a diameter of 11,6μπι with a geometric standard deviation of 1.56. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell consists mainly of the reaction product of a dimeric acid with a linear diamine and that the core consists mainly of the reaction product of isopropylidenediphenoxypropanol and adipic acid , oxidized steel and soot kp / cm ² a degree of fixation of 1.4 Taber cycles and at a pressure of 71.5 kp / cm ² of 3.3 Taber cycles.

_Jo example 12

A magnetic toner is prepared from a solution containing 320 g of a polystyrene and 320 g of the reaction product of isopropylidenediphenoxypropanol and sebacic acid having a number average molecular weight of 2,410 in a mixture of chloroform and cyclohexane at a volume ratio of chloroform: cyclohexane of 1: 3. Carbon black and magnetic nickel-tin alloy particles are dispersed in the solution by vigorous stirring. The final concentrations are 4.75% polystyrene, 4.75% of the reaction product of isopropylidenediphenoxypropanol and sebacic acid, 0.5% carbon black, 1.1% nickel-tin alloy and 89.0% solvent.
The solution is spray-dried with the dispersed carbon black and the nickel-tin alloy using a spray dryer of the type described having a diameter of 76.2 cm at a rotational speed of 50,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the dry air is 63.3 ° C and the outlet temperature of the air 47.8 ° C. The dry product is a toner with a volume average particle size of 16.8 μm with a geometric standard deviation of 1.67. The point of adhesion, the caking and the interruption of the crushed particles with the scanning electron microscope indicate that the shell is mainly composed of; Polystyrene and that the core consists mainly of the reaction product of isopropylidenediphenoxy-

bo propanol and sebacic acid, carbon black and the nickel-tin alloy consists. The toner particles are used in place of the developer in the test device of the comparative experiment. With essentially identical Test conditions except that the copy

b5 are pressure-fixed without the aid of heat, a degree of fixation at a pressure of 53.6 kg / cm ² of 0.5 tab cycles and ^{at a pressure of 71 kg / cm 2} of 22.0 tab cycles is obtained.

909 618 / 19f

Example 13

A magnetic toner is prepared from a solution containing 800 g of polystyrene and about 800 g of the reaction product of isopropylidenediphenoxypropanol and sebacic acid having a number average molecular weight of 2230 in a mixture of chloroform and cyclohexane at a volume ratio of chloroform: cyclohexane of 1: 3. In the solution, soot particles and crushed permeable iron particles are dispersed by vigorous stirring. The final concentrations are 4.75% polystyrene, 4.75% of the reaction product of isopropylidenediphenoxypropanol and sebacic acid, 0.5% carbon black, 1.0% iron particles and 89.0% solvent . The solution with the dispersed carbon black and the iron particles is spray-dried using a spray dryer of the type described with a diameter of 1.52 m at a speed of 21,000 rpm and a feed rate of 200 ml / min. The inlet temperature of the drying air is 64.4 ° C and the outlet temperature of the air is 47.8 ° C. The dry product is a toner with a volume average particle size corresponding to a diameter of 17.0 μm with a geometric standard deviation of 1.73. The sticking point, caking and examination of the crushed particles with a scanning electron microscope indicate that the shell is mainly composed of polystyrene and that the core is composed mainly of the reaction product of isopropylidenediphenoxypropanol and sebacic acid, carbon black and iron particles. The toner particles are used in place of the developer in the test device of Example 1. Under essentially identical test conditions except that the copies are pressure-fixed without the aid of heat, a degree of fixation at a pressure of 71.5 ^{kg / cm 2} becomes 33.0 Taber cycles and at a pressure of 90 kg / cm ² 43.0 Taber cycles obtained. It can be seen from these results that this toner composition at pressures of 71.5 kg / cm ² and 90 kg / cm ² and at ambient temperature gives a degree of fixation which is significantly greater than that of the toner composition of Example 1 at a fixing temperature of 60.0 ⁰ C.

Example 14

A magnetic toner is made from a solution containing 190 g of a polystyrene and 284 g of des Reaction product of isopropylidenediphenoxypropanol and sebacic acid having a number average molecular weight of 2230 in a mixture of Ethyleiidichlorid and Cyclohexane at a volume ratio of ethylene dichloride: cyclohexane of 2.2: 1 contains. In the solution, stir vigorously Soot and crushed permeable iron particles dispersed. The final concentrations are 1.1% polystyrene, 1.7% of the reaction product of isopropylidenediphenoxypropanol and sebacic acid, 0.1% carbon black, 0.5% Iron particles and 96.5% solvent. The solution with the dispersed carbon black and iron particles is under Using a spray dryer of the type described with a diameter of 76.2 cm at a Rotation speed of 50,000 rpm and a feed rate of 200 ml / min spray dried. The inlet temperature of the drying air is 58.3 ° C and the outlet temperature of the air 43.3 ° C. The dry product is a toner with a volume average particle size accordingly a diameter of 10.4 μm with a geometric standard deviation of 1.81. Of the Adhesion point, caking and examination of the crushed particles with the scanning electron microscope suggest that the shell is mainly made of polystyrene and that the core mainly from the reaction product of isopropylidenediphenoxypropanol and sebacic acid, carbon black and

ι »There is iron particles The toner particles become Location of the developer used in the test device of Example 1 at substantially identical Test conditions except that the copies are pressure-fixed without the aid of heat,

A degree of fixation of 7.0 Taber cycles is obtained at a pressure of 53.6 kp / cm ^{2 and} a degree of fixation of 8.8 Taber cycles is obtained ^{at a pressure of 71.5 kp / cm 2.}

Example 15

An experiment was made to determine whether the flow properties of the toner of the example 15 could be improved. Poor toner flowability may occur in the packaging of the toner and the Toner release will become a major problem. Consequently

r> was the flowability of the toner material of the Example 14 with various amounts of powdered hydrophobic silica. the Flowability was measured by determining the amount of toner that passed through a sieve

so controlled conditions went through. The received The results agree with the observed dispensing behavior in a simulated machine test. The silica was in the toner in concentrations of 0.02 to 1.0 wt% based on the

s> Weight of the toner, dispersed by placing the samples in a barrel drum. The triboelectric values for these samples were compared to homogeneous 450 ^ m glass carrier beads measured. The developers came in three containers of 226.8 g

■ Mill for κι hours by rolling. The triboelectric Measurements were taken after 10, 30 and 180 minutes. The values obtained suggest that much less than 1% silica is sufficient to greatly increase the toner flowability and the

Γ) pronounced triboelectric properties of the toner to influence. It has been found that the addition of 0.02% silica gives a toner flowability which is comparable to that of a common one. The addition of 0.1% silica improved significantly

vi the stability of the triboelectric properties of the Example 14 toner material over time and also gave an acceptable triboelectric value. It There was also evidence that the addition of silica was reducing the triboelectric variations

V) between different approaches of the toner material of Example 14 decreased. The addition of powdered silica improved the flowability of the Toner material of Example 14 significantly in machine testing.

Example 16

A magnetic toner is formed from an r solution containing 431 g of a polystyrene and 431 of the Reaktionsprodukles of Isopropylidendiphenoxypro- M g propanol and adipic acid having a number average molecular weight of 3275 in a mixture of chloroform and heptane at a volume ratio of chloroform to heptane 1?: 1.3 contains. A

19 20

Tetraisohexylsulf'onamido copper phthalocyanine dye spray dried at 200 ml / min. The inlet temperature is dissolved in the solution by stirring. In the drying air is 69.4 ° C and the outlet temperature solution by vigorous stirring the magnetic door of the air becomes 56.7 ° C. The dry product is a toner Iron oxide particles dispersed final concentrations with a volume average particle size are 4.8% polystyrene, about 43% of the reaction product-> corresponding to a diameter of 14.8 µm with a tes of isopropylidenediphenoxypropanol and adipine- geometric standard deviation of 1.51. It shows acid, 0.5% phthalocyanine dye, 1.0% iron oxide and that in the machine theses of this toner 90.0% solvent. The solution with the dispersed provides excellent copies

Iron oxide is made using a spray dryer The polymeric used in the examples

of the type described with a diameter of 76.2 ι ο core materials always have a viscosity

cm at a rotational speed of less than the previously specified test conditions

50,000 rpm and a loading speed of 5 χ 10 ⁴ Ws 10 ⁸ POiSe.

Claims (7)

Patent claims: 1. Electrostatographic magnetic toner with a particle size of 0.5 to 1000 μπι and a caking temperature of at least 37.8 ° C, encapsulated in a polymeric shell material, a colorant and an adhesive polymeric core material with a viscosity of 5 χ 10 ⁴ to 10 ⁸ PoISe at a shear rate of 75 sec " ¹ and the temperature of the pressure fixing device used and a freezing temperature below or not more than a few degrees above the temperature to which the toner image formed from the toner material is heated, and optionally contains finely powdered hydrophobic silicon dioxide, thereby characterized in that the polymeric core material additionally contains magnetic or magnetizable particles. 2. Toner according to claim 1, characterized in that the magnetic or magnetizable Particles made of metals, metal alloys, metal compounds, ferromagnetic ferrites or their Mixtures exist. 3. Toner according to claim 1 or 2, characterized in that the magnetic or magnetizable particles have a particle size of 0.1 to 1 μπι have. 4. Toner according to one of claims 1 to 3, characterized in that the magnetic or magnetizable particles are contained in an amount of 1 to 50% by weight based on the weight of the toner material. 5. Toner according to one of claims 1 to 4, characterized in that the polymeric shell material has a caking temperature of at least 37.8 ⁰ C, a freezing ^{temperature above 50 0} C, a modulus of elasticity of more than 7.03 kg / cm ² and a Has compressive strength of more than 35.2 kg / cm ² . 6. Toner according to one of claims 1 to 5, characterized in that the polymeric core material has a viscosity of 5 χ 10 ⁴ to 10 ⁸ poise at a shear rate of 75 sea- and ambient temperature and a freezing temperature below 30 ^° C 7. The method for producing the toner according to claim 1, characterized in that the adhesive polymeric core material and the polymeric shell material dissolves in a solvent, in the solution dissolves or disperses the colorant and the magnetic or magnetizable particles dispersed, solvent removed until at least part of the colorant, part of the polymeric core material and a part of the magnetic or_magnetisable particles from the Separate solution, and that one then removed from the solution so long further solvent until the polymeric shell material deposits around the colorant, the polymeric core material and the magnetic or magnetizable particles.