DE2402982A1 - DEVELOPER MIX - Google Patents

Description

24 854 n / wa

XEROX CORPORATION, ROCHESTER, NEW YORK

United States

Developer mix

The invention relates generally to electrostatographic Imaging systems and in particular to improved developer materials and their use.

The formation and development of images on the surface

- 2 409831/0992

Electrostatic photoconductive materials are well known. The basic electrostatographic Method as described by C. F. Carlson in U.S. Patent 2,297,691 involves application a uniform electrostatic charge on a photoconductive insulating layer, exposure of the Layer with a light-shadow image while consuming the charge on the areas of the layer that are exposed to the light and developing the resulting electrostatic latent image by depositing a finely divided electroscopic material called "toner" on the image. The toner is normally attracted to those areas of the layer that retain charge, thereby creating a toner image corresponding to the electrostatic latent image. This powder image can then be applied to a carrier surface, like paper. The transferred image can then be on the support surface, for example permanently fixed by heat. Instead of forming the latent image by uniform charging the photoconductive layer and subsequent exposure of the layer through a light shadow image the latent image can be formed by charging the layer directly in the image configuration. The powder picture can then be fixed on the photoconductive layer when an elimination of the powder image transfer step is desired. Other suitable fixation methods, such as solvent or coating treatment, can be substituted for the heat setting step described above.

409831/0992

There are many methods of applying the electroscopic particles to what is to be developed known electrostatic latent image. A development process as described by E.N. Wi-se in US Pat U.S. Patent 2,618,552 is known as "cascade" development. In this process, a developer material, which comprises relatively large carrier particles, finely divided toner particles adhering electrostatically to the surface of the carrier particles the surface carrying the electrostatic latent image is conveyed, rolled or sprayed or "cascaded". The composition or the material of the toner particles is selected in such a way that it corresponds to that of the carrier particles opposite triboelectric polarity exhibit. When the mixture is cascaded or rolled over the image-bearing surface, the Toner particles are electrostatically deposited and attached to the charged portion of the latent image while they are not deposited on the uncharged or background portions of the image. Most of the accidentally Toner particles deposited on the background are removed by the rolling carrier, which is evident to the greater electrostatic attraction between the toner and the carrier than between the toner and the discharged background. The carrier particles and the unused toner particles are then returned. This methodology is extremely useful for developing tape copy images. The cascade development process represents the most widely used commercial electrostatographic

409831/0992

Development methodology: dar. An office copier for general purposes embodying this methodology are described in U.S. Patent 3,099,943.

Another methodology for developing electrostatic latent images is the "magnetic brush" process as described, for example, in US Pat. No. 2,874,0β3 is. In this process, a developer material containing toner and magnetic carrier particles is through worn a magnet. The magnetic field of the magnet causes an alignment of the magnetic carrier in one brush-like configuration. This "magnetic brush" is attached to an electrostatic latent image bearing Surface brought into contact and the toner particles are transferred from the brush to the electrostatic latent Image drawn by electrostatic attraction.

Another technique for developing electrostatic latent images is the so-called "touch-down" process as described, for example, in U.S. Patents 2,895,847 and 3,245,823 (Mayo) is. In this process, a developer material is passed through to a latent image bearing surface a support layer, such as a fabric or sheet, is carried and then corresponding to this Image deposited.

It has been found that developing a latent image resulting from negative electrostatic

409831/0992

There is an electroscopic powder and charges Carrier combination should be chosen in which the powder is triboelectric with respect to the granular carrier is positive while developing a latent image made up of positive electrostatic charges consists, an electroscopic powder and carrier should be chosen such that the powder is opposite the carrier is triboelectrically negative. Often with any type of pushing, it is desirable to have one Make a reverse copy of an original. This creates a negative copy of a positive one Original or, on the other hand, a positive copy of a negative original meant. In the case of electrostatographic In printing, image reversal can be achieved by applying developer powder to the image, which is repelled from the charged areas of the image and adheres to the discharged areas.

The triboelectric relationship between the electroscope! - see powder and the carrier depends on their relative positions in a triboelectric series in which The materials are arranged such that each material is electrostatically charged with a positive charge Contact with any material in the line below it and charged with a negative charge when it is brought into contact with any material which is above it in the Row is located.

409831/0992

When reproducing high-contrast copies, such as letters, drawings, etc., it is desirable to use the electroscopic powder and carrier materials in such a way that their mutual electrification sufficient to cause the toner particles to adhere electrostatically to the carrier surface. That The extent of such electrification is usually determined by the distance between their positions in of the triboelectric series, i.e. the greater the distance with which they are separated from each other, the greater the mutual electrification and the closer they are in line, the less mutual electrification is.

Suitable coated and uncoated or coated and uncoated carrier materials for the Cascade, magnetic brush and "touchdown" developments are well known. The carrier will provide whatever is appropriate solid material, provided that the carrier accepts a charge that is opposite Polarity to that of the toner particles when brought into close contact with the toner particles so that the toner particles adhere to and surround the carrier. With a suitable choice of materials according to their position in the triboelectric series are the polarities of their charge when the Materials such that the electroscopic toner particles adhere to the surface of a carrier and are coated on this and also on that part that

409831/0992

Adhere to the electrostatic image bearing surface, which has a greater attraction for the toner than the carrier having.

Carrier particles are generally made from or coated with materials, whichever is appropriate have triboelectric properties as well as certain other physical characteristics. Therefore, the materials used as carrier particles or the coatings on them have a triboelectric value, which is adapted to the triboelectric value of the toner, so that the electrostatic adhesion of the toner on the carrier particles and the subsequent transfer of the toner from the carrier particles to allow the image on the plate. In addition, the triboelectric properties of the carrier particles be relatively uniform in order to enable uniform absorption and subsequent deposition of the toner. The materials used on the carrier particles should preferably have a medium hardness, thus the plate or drum surface on which the electrostatic image is initially placed are not scratched, while they should be hard enough to withstand the forces to which they will be subjected during repatriation. The carrier particles as well as their surface should not consist of materials which are so brittle that either flocculation of the surface or particle breakage is caused by the forces exerted on the carrier during the return. the

409831/0992

Flocculation of these causes undesirable effects in that the relatively small flaky particles eventually transferred to the copy surface, whereby they with the deposited toners in the Get across and create imperfections in the copy image. It also causes the flocculation of the Carrier surface that the resulting carrier does not have uniform triboelectric properties, when the carrier is composed of a material derived from the surface coating thereon is different. This leads to the undesired, uneven absorption of the toner by the carrier and to uneven deposition of the toner on the image. In addition, when the carrier particle size decreases is, removal of the resulting small particles from the plate becomes increasingly difficult. Therefore, the types of materials that can be used for the manufacture of carriers or for carrier coatings are limited, because other physical properties they exhibit are undesirable as discussed above Can produce results.

Although conventional developer materials are usually used to produce good quality images are capable, they have serious disadvantages in certain areas. The developer materials must be free flow to ensure accurate metering and uniform distribution during the development and developer return phases of the electrostatic graphic process to facilitate. Some developer materials are

- 9 409831/0992

24Ü2982

although they have desirable properties, such as suitable triboelectric characteristics, therefore unsuitable, as they tend to caking, bridging and agglomeration during handling and storage. The adhesion of carrier particles to reusable Electrostatographic imaging surfaces causes the formation of undesirable scratches on the surfaces during the process the image transfer and surface cleaning stages. The tendency of the carrier particles to adhere to the imaging surfaces is then exacerbated when the Support surfaces are rough and irregular. The triboelectric and flow properties of many carriers are adversely affected at high relative humidity. For example, the triboelectric values of some carrier materials fluctuate with the changes relative humidity and are therefore particularly suitable for use in electrostatographic systems in automatic devices, the carriers with stable and predictable triboelectric values require, undesirable.

i the stability of the triboelectric properties factor influencing the carrier is the sensitivity of the carrier material to "toner impact" When the carrier particles are applied in automatic devices and recycled through many cycles could be the many collisions that exist between the beams and other surfaces in the Device done, cause the toner particles carried on the surface of the carrier particles with

- 10 409831/0992

- ίο -

fused to the carrier coatings or to others Way to be forced into it. The gradual accumulation of permanent on the surface of the wearer adhered toner material leads to a change in the triboelectric value of the carrier and carries directly to the deterioration of the copy quality due to the eventual destruction of the toner carrying capacity of the carrier at.

Therefore, there is a continuing need for a better developer material for developing electrostatic ones latent images.

The invention has therefore set itself the task of developing developer materials which overcome the above-mentioned disadvantages.

Another object of the invention is to provide carrier particles which are more uniform triboelectric Have properties.

The invention is further directed to providing low density carrier particles that oppose are more resistant to toner impact.

Another object of the invention is to provide free flowing developer materials.

Another object of the invention is to provide carrier particles that contain controlled electrical

- 11 -

409831/0992

24Q2982

- li -

have statographic reactions.

The invention is further directed to providing improved developer materials useful in electrostatographic Positive development processes can be used.

Another object of the invention is to provide improved developer materials for use in electrostatographic Negative development processes can be used.

Another object of the invention is to provide improved developer materials compared to known developer materials have improved physical and chemical properties.

The foregoing and other objects are, generally speaking, provided by the creation of electrostatographic Composite carrier particles met the one represent an integral combination of two or more materials. It has been found that use of composite carrier particles which are an integral combination of two or more materials make it possible the electrostatographic response of a carrier through appropriate selection of the component materials and the relative amount of each component material included in the Carrier particle mass is applied to adjust to size. In addition, it has also been found that the resistance or resilience, carrier

- 12 -

409831/0992

£ 402982

particle density and the magnetic properties some of the physical properties obtained through the use of the composite carrier particles according to the invention can be changed and regulated. In the field of electrostatography, the use of Low density composite carrier particles with pressure fixable toner materials of particular interest. Although print-fixable toner materials generally use less energy to produce a permanent one Require image during the fixation stage, they are also generally more sensitive to the impact of toner on carrier materials. Hence it will be detrimental Toner-carrier interactions, such as the impact of toner on carrier particles, through the use of Low density composite substrates according to the invention are minimized.

According to the invention, composite materials are in the form of electrostatographic carrier particles or beads applied to electrostatographic image development systems. Composite materials are used here as any integral combination of two or more materials defined. As representative examples of composite materials, Len homogeneously dispersed, fine, powdery, ceramic or metal oxide fillers in a rubber, plastic or ceramic matrix; organic fillers, which are miscible or immiscible in an organic matrix such as plastic or rubber); Metal fillers in a ceramic, plastic or rubber matrix and ceramic or metal oxide fillers in one

409831/0992

Metal matrix are mentioned. Metal alloys are also defined by the definition given here for a composite material with includes. Next there are two or more physical phases of the same material within a body regarded as encompassed by the definition given for the composite material. An example of such a thing Composite material represents the presence of two or more homogeneously dispersed crystalline phases of the same Material within a ceramic body, such as that resulting from heat treatment of a ceramic material results. Another example of such a composite material is the product This is caused by the development of a metallic oxide layer on the surface of a metal or metallic Oxide support particle is obtained by either heat treatment or chemical reaction. Another example occurs when a steel carrier bead has a carburization, Nitridation or carbon nitridation process can be subjected to, creating a surface layer is generated on the steel support bead, which has a high respective carbon, nitrogen or Has carbon-nitrogen content. It will pointed out that the thickness and the content of such a surface layer to create the desired Composite backed ulcer compositions and characteristics can be controlled. If desired, the entire Carrier body to be diffused through with the above-mentioned element. It is further considered that the composite substrates of the invention contain a magnetic additive such as fine iron powder or ceramic

- 14 409831/0992

Ferrite within a plastic or rubber matrix to create low density composite carrier particles included, which (capable of being used in magnetic brush development systems to be used. It is also contemplated that the composite support particles for the electrostatographic Positive or negative development systems can be provided by the invention.

In making the composite carrier particles according to the invention, wherein the composite carriers are an integral combination of two or more materials, the particular components chosen are dependent on the toner chosen so that when the carrier and toner are mixed together to form a developer mixture, the carrier is capable of imparting a positive triboelectric charge or a negative triboelectric charge to the toner. The components can be selected with reference to any of the triboelectric series known in the art. As representative examples of such triboelectric series, the following can be given: Shaw and Levy, EWL Proc. of Royal Society, Ij58, p. 506 (1932); The Smithsonian series, published in Smithsonian Physical Tables, p. 375, 9th Rev. Ed. (195 ² OJ and Hersh and Montgomery Textile Research Laboratories, _28, p. (1956).

As representative examples of materials that generally impart a negative charge to the toner, can be mentioned: glass, metal oxides, such as calcium oxide,

- 15 409831/0992

Titanium oxide, iron oxide, calcium titanate, etc .; Metals such as lead, nickel, copper; Ferrites] polymers such as ethyl cellulose, acrylic polymers, aorylate polymers, and the like. As representative examples of materials which generally impart a positive charge to the toner, there can be mentioned: metals such as selenium; Polymers such as halogen polymers; eg polymers of tetrafluoroethylene, polymers of vinyl chloride, polymers of vinyl fluoride, polymers of vinylidene fluoride, polymers of chlorotrifluoroethylene; Butyl rubber; and the same. The selection of the required materials is within the knowledge of the person skilled in the art in view of the teaching presented here.

When producing composite beams from two or more materials, the selected materials can be used in one such a manner intimately mixed together so that the area size of each of the components is at least is two orders of magnitude smaller than the average particle size of the toners to be used, whereby the composite is capable of imparting the charge of the desired polarity to the toner. It will care indicated that the area size of each of the components could be larger than the average particle size of the toner and in some cases slightly smaller than the average particle size of the toner below the premise that the area size is a size necessary to bestow the desired charge on the individual toner is sufficient.

- 16 -

AO 983 1/0992

The intimate mixture of the two or more composite support components can be formed by intimate mixing of the components, for example by grinding, melt mixing, Loading, kneading, alloying, heat treatment, disc pelletization, spray drying and the like, as is known in the art. Alternatively, one of the components can be formed with pores and vacuum impregnated or otherwise filled with the other component. It will also noted that the area size of each of the different components in such methodologies by choosing the particle size of the components and the pore size of the porous material can be regulated in each case. The exact process for making an intimate mixture of at least two components is believed to be within the reach of those skilled in the art Considered based on the teachings given here, so no further explanation for the perfect Understanding of the present invention should be considered necessary. The relative amounts or ratios of the at least two components used in making the composite beams vary with the components and toners used.

If the composite carriers of the invention are to be used in cascade development processes, the carrier may comprise a combination of materials which are only capable of imparting a negative or positive polarity charge to a bulk toner. Alternatively, only the composite beam surface can be used

- 17 -409831/0992

represent a material capable of imparting such triboelectric properties. For the magnetic brush development process the composite beam may comprise a combination of materials wherein a magnetic component such as iron in Particulate form or ceramic ferrites, in a matrix material such as a plastic or rubber, to obtain dispersed or entrapped in a low density composite substrate. As with composite beams for The cascade development process, can use both composite beams that are used to confer only one charge negative or positive polarity to a toner mass are capable of being used for the magnetic brush development systems be generated. Therefore, it will be apparent to those skilled in the art that the composite beams can be obtained according to the invention which have regulated electrostatographic reactions and further wherein the nature of an applied magnetic component of such xerographic nature is that it does not adversely affect the electrostatographic response of the composite support will.

The composite carrier particles according to the invention can be coated with any suitable sealing material. Typical electrostatographic carrier particle coating materials include vinyl chloride-vinyl acetate copolymers, styrene-acrylate-organosilicon terpolymers, natural resins such as rubber, rosin, copal, kauri resin, resinous secretions present in the resin of daemonorops ^{propinquin, dragon t salaplod} Styrax;

- 18 409831/0992

thermoplastic resins including polyolefins such as polyethylene, polypropylene, chlorinated polyethylene and chlorosulfonated polyethylene, polyvinyls and polyvinylidenes, such as polystyrene, polymethylstyrene, polymethyl methacrylate, Polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, Polyvinyl ethers and polyvinyl ketones; Fluorocarbons, such as polytetrafluoroethylene, polyvinyl fluoride, Polyvinylidene fluoride; and polychlorotrifluoroethylene; Polyamides such as polycaprolactam and polyhexamethylene adipamide; Polyesters such as polyethylene terephthalate; Polyurethanes; Polysulfides, polycarbonates; thermosetting resins including phenolic resins such as phenol-formaldehyde, phenol-furfural and resorcin-formaldehyde resins; Amino resins such as urea-formaldehyde and melamine-formaldehyde resins ; Polyester resins; Epoxy resins; and the like.

Many of the above and other typical carrier coating materials are disclosed by LE Walkup in US Pat. No. 2,618,551; BP Jacknow et al in U.S. Patent 3,526,533; and RJ Hagenbach et al in U.S. Patents 3,533,835 and 3,658,500. If the composite carrier particles are coated according to the invention, S is A ny suitable electrostatographic carrier coating thickness to be applied. However, a carrier coating of a thickness which is at least sufficient to form a thin continuous film on the carrier particle is preferred because the carrier coating then has a thickness sufficient to withstand abrasion and to prevent pinholes from causing damage

- 19 4098 3 1/0992

adversely affect triboelectric properties of the coated carrier particles. In general, in cascade and magnetic brush development, the carrier coating can comprise from about 0.1 to about 10.0 weight percent, based on the weight of the coated composite carrier particles. Preferably, the carrier coating should comprise from about 0.9 to about 2.4% by weight , based on the weight of the coated carrier particles, since maximum durability, toner impact resistance and copy quality are achieved. In order to achieve further variations in the properties of the coated composite carrier particles, known additives such as plasticizers, reactive and non-reactive polymers, dyes, pigments, wetting agents and mixtures thereof can be mixed with the coating materials. In cascade development systems, a coated or uncoated final composite carrier particle that has an average diameter between about 50 Ai (microns) and about 1,000 microns is preferred because the carrier particle then has sufficient density and inertness to allow adhesion to the electrostatic image during the To prevent cascade development process. The adhesion of the carrier particles to an electrostatographic drum is due to the formation of deep scratches on the drum surface during the image transfer and drum cleaning stages, especially when the cleaning is carried out by a fabric cleaner, such as the fabric made by WP Graff Jr. et al in U.S. Patent J> 186 is undesirable.

- 20 -

409831/0992

Any suitable known toner material can be used with the composite carriers of the invention. Typical Toner materials include copal gum, sandarak gum, Colophony, coumarone resin, asphalt, gilsonite, phenol-formaldehyde resin, Rosin-modified phenol-formaldehyde resins, methacrylic resins, polystyrene resins, polypropylene resins, Epoxy resins, polyethylene resins, polyester resins and mixtures thereof. The specific one to use Toner material obviously depends on the separation of the toner particles from the composite carrier within the triboelectric And should be such that the electrostatic adhesion of the toner particles to the Carrier surface is caused. Among the patents, which describe electroscopic toners are U.S. Patents 2,659,670 (Copley); U.S. Patent 2,753,308 to Landrigan; U.S. Patent 3,079,512 (Insalaco); US-PS Reissue 25 I36 (Carlson) and U.S. Patent 2,788,288 (Rheinfrank et al). These toners generally have an average particle diameter between about 1 and 30 / rev (microns).

Any suitable coloring agent such as pigment or dye can be used to color the toner particles will. Toner dyes are known and include, for example, carbon black, nigrosine dye, aniline blue, calccfoil blue, Chrome yellow, ultramarine blue, chlnoline yellow, methylene blue chloride, monastral blue, malachite green - oxalate, lamp soot, Rose Bengal, Monastral Red, Sudan Black BM and their mixtures. The pigment or dye should be in be present in the toner in an amount sufficient to give it a strong coloring so that it

- 21 -

409831/0992

can form a clearly visible image on a recording element. Preferably, the pigment is used in an amount of about 3 to about 20 wt.% * Based on the total weight of the colored toner used because images can be obtained high quality. When the toner colorant employed is a dye, much smaller amounts of the colorant can be employed. Any suitable conventional toner concentration can be used with the composite carriers of the invention. Typical toner concentrations for the cascade and magnetic brush development systems comprise about one part by weight of toner with about 10 to about 200 parts by weight of carrier.

Any suitable organic or inorganic photoconductive material can be used as the recording surface applied with the composite beams according to the invention will. Typical inorganic photoconductor materials include: sulfur, selenium, zinc sulfide, zinc oxide, zinc cadmium sulfide, Zinc magnesium oxide, cadmium selenide, zinc silicate, calcium strontium sulfide, cadmium sulfide, mercury iodide, Mercury oxide, mercury sulfide, indium trisulfide, Gallium selenide, arsenic disulfide, arsenic trisulfide, arsenic triselenide, antimony trisulfide, cadmium sulfo-selenide and their Mixtures. Typical organic photo-pus include: Quinacridone, phthalocyanine pigments, triphenyl

amine, 2,4-bis- (4,4 ^l -diethylamino-phenol) -l,; 3,4-oxadiazole, N-isopropyl-carbazole, triphenyl-pyrraL, 4,5-diphenylimidazolidinone, 4,5- Diphenylimidazolk2näthione, 4,5-bis- (4'-aminophenyl) -imidazolidinone, 1,5-dizyanonaphthalene, 1,4-dicyano-

- 22 -

409831/0992

2 ^ 02982

naphthalene, aminophthalonitrile, nitrophthalodinitrile, l, 2,5,6-tetra-azac-yclooctotetraen- (2,4,6,8), 2-mercaptobenzothmzol-2-phenyl-4-diphenylidenoxazolone, 6-Hydroxy-2,3-di- (p-methoxyphenyl) -benzofuran, 4-dimethylaminobenzylidene-benzhydrazide, 3-benzylidene-amino-carbazole, polyvinylcarbazole, (2-nitro-benzylidene) -p- -bromaniline, 2,4-diphenyl-quinazoline, 1,2,4-triazine, 1,5-diphenyl-3-methyl-pyrazoline, 2- (4'-Dimethyl-aminophenyl) -benzooxazole, 3-amino-carbazole and mixtures thereof. ! Representative patents in which photoconductive materials are described, include US Pat. No. 2,8O3,542 (Ullrich), U.S. Patent 2,970,906 (Bixby), U.S. Patent 3,121 ΟΟβ (Middleton), U.S.P. 3,121,007 (Middleton) and U.S. Patent 3,151,982 (Corrsin).

The surprisingly better results obtained with the electrostatographic composite supports according to the invention can be due to many factors. For example, the composite beams according to the invention have smooth external surfaces that are highly resistant to breakage, flaking and flaking. Both Cascade development systems, the smooth surface favors the rolling action of the carrier particles over the electrostatographic surfaces and reduces the tendency of the carrier particles to adhere to the electrostatographic Surfaces. When these composite supports are applied in electrostatographic development systems carrier life is unexpected, especially in terms of toner impact resistance, elevated. In addition, the composite carrier materials according to the invention appear to be responsible for the stability of the triboelectrics

- 23 40983 1/0992

24Ü2982

Properties of the carrier over a wide range of relative humidity. As a result of their triboelectric Properties can be applied to these carrier materials in the reversal development of positively charged images will. Furthermore, the composite beams according to the invention provide more uniform triboelectric properties than the current carriers for use in electrostatographic development systems. Furthermore show the composite beams according to the invention extremely good service life, durability, copy quality, Quality maintenance, less carrier bead sticking and agglomeration and also exhibit improved Abrasion resistance, thereby minimizing substrate delamination and flaking.

The low-density composite beams according to the invention exhibit sufficient hardness at normal operating temperatures to prevent the impact of an impact (inpaction) and have triboelectric values such as that they work with a wide variety of currently available toners in current electrostatographic processes can be used and they are hydrophobic, giving them a predictable triboelectric value keep. Thus, the composite carrier particles according to the invention exhibit desirable properties that match theirs allow wide application in currently available electrostatographic systems.

The following examples, which are not control examples, define, describe and compare the

- 24 408831/0992

preferred method of using the composite supports according to the invention in electrostatographic application forms Further. Unless otherwise stated, parts and percentages are by weight.

Example I.

There are composite carrier prepared by dispersing about 60 g of powdered Ferritkeramikteilchen having an average particle diameter of about 1 Ai in about 50 g of polyvinyl acetate having a Peststoffgehalt of about 70 percent. ^, Based on the weight of the polymer. The solvent is removed, the dispersion solidified, dried, ground and sieved to an average diameter particle size of 100 microns. About 9 9 parts by weight of the resulting carrier particles are mixed with about 1 part by weight of a toner composition comprising styrene-n-butyl methacrylate copolymer, polyvinyl butyral and carbon black and produced in the manner described in US Pat. No. 3,079,324. The developer mix is cascaded over a surface bearing an electrostatographic latent image. The developed image is electrostatically transferred onto a sheet of paper, on which it is melted by means of heat. The remaining powder is removed from the electrostatic imaging surface by a cleaning cloth of the type manufactured by WP Graff Jr. et al in U.S. Patent 3,186,838. It is found

- 25 409831/0992

that the composite beam behaves well and the print quality is good during the test.

Example II

There are composite reversal carrier particles or after dispersing about 60 g of powdered ferrite ceramic particles, which have an average particle diameter of about 1 / _u , in about 50 g of a polyvinyl chloride solution, which has a solids content of about 70% by weight, based on the weight of the polymer, generated. The solvent is removed, the solidified dispersion, dried, ground and classified to an average diameter size of from about 100 part Ai sieved. A developer mixture is formed by mixing about 99 parts by weight of the resulting carrier particles with about 1 part by weight of the toner particles of Example I. In device tests using magnetic brush development of a positively charged, reusable imaging surface and development of the discharged image areas with the unexposed areas still positively charged, it is found that the composite carrier behaves well and the reverse print quality is good during the test.

Example III

There are composite carrier particles by arranging 1500 g

- 26 409831/0992

soft steel (AISI-C 1015) particles with an average diameter of about 100 ax produced in a carburizing furnace. It is introduced as a gas carbon monoxide in the furnace where the carbon (F 1400 ⁰⁾ absorbed by the steel during heating of the steel at about 760 ° C for about 0.5 hours. The steel particles that have been carburized, are quenched with water as it exits the furnace and heated to about 177 ° C (550 ⁰ F). The examination of the carburized steel particles shows that the carbon content at the surface of the particles is about 1 wt.% And that the steel particles have a soft and tough core and a hard shell or skin. A developer mix is formed by mixing about 99 parts by weight of the resulting carrier particles with about 1 part by weight of the toner particles of Example I and the development procedure of Example I is followed. It is found that the composite carrier behaves well and the print quality is good during the test.

Example IV

Composite support particles are prepared by placing about 1500 grams of mild steel (1020 steel) particles an average diameter of about 100 microns in a sodium cyanide bath. The steel particles are treated in the cyanide bath during about 0.25 hours at a temperature of about 843 ° C (155o F ^0). The steel particles are then removed from the cyanide bath and immediately quenched in a water bath. Examination of the cyanide-treated steel filings shows that

- 27 -

409831/0992

the hardness of the surface or shell of the particles is greater is than can be attributed to carbon, and microscopic examination shows it was mixed with carbide Nitride crystals. It creates a developer mix by mixing about 99 parts of the resulting Carrier particles prepared with about 1 part of the toner particles of Example I and the development process of Example I applied. It is found that the composite carrier behaves well and the print quality during the exam is good.

Example V

Composite support particles are obtained by heating about 1500 grams of soft steel particles containing about 0.9 to about 1.5 weight percent aluminum and having an average diameter of about 100 / rev in a stream of dry ammonia gas at a temperature between about 482 and 649 ° C (900 and 1200 ⁰ P) produced for about 48 hours.

The ammonia gets on the surface of the carrier particles decomposes and the nitrogen is absorbed by the steel and aluminum to form a hard nitride. The carrier parts are cooled in the furnace to prevent peeling or oxidation. It will be a Developer mix by mixing about 99 parts of the resulting carrier particles with about 1 part of the Generated toner particles of Example I and the development

- 28 409831/0992

24Ü2982

procedure of example I applied. It is found that the composite carrier behaves well and the print quality is good during the attempt. Substantially no toner impact is observed.

Example VI

Composite support particles are produced as in Example III except that ammonia is incorporated into the gaseous carburization atmosphere of Example III is introduced and the treated particles in the Oven to be cooled down. Examination of the steel particles treated in this way indicates that the hardness of the The surface or shell of the particles is larger than can be attributed to the carbon and one microscopic examination shows nitride crystals mixed with carbides. It will be a development community by mixing about 99 parts of the resulting carrier particles with about 1 part of the toner particles of Example I and the development procedure of Example I applied. It is found that the composite carrier behaves well and the print quality is good during the test. It there will be essentially no toner impact effect or no carrier wear observed.

Example VII

There are low density composite carrier particles through

409831/0992 -29-

Melting from about 600 g methyl methacrylate and 900 g of about Schmelzvermisehung herein made of a soft-magnetic nickel-Zinkferritpulvers an average particle diameter of about 1 Ai to form a composite, comprising about 60 wt.% Of Perritpulvers. The mixture is cooled and formed into carrier particles having an average particle size between about 90 and about 110 Å . About 99 parts by weight of the carrier particles are mixed with about 1 part by weight of pressure-fixable toner particles, which are carbon black and the reaction product of isopropylidenediphenoxypropanol and adipic acid encapsulated in polystyrene. In device trials using magnetic brush development of a positively charged, reusable imaging surface, the low density composite substrate is found to perform exceptionally well and the print quality during the trial is excellent. The toner impact is extremely low and essentially no carrier wear is observed.

Example VIII

There are composite carrier particles produced low density by mixing about 1500 g of iron powder of an average particle diameter of about 1 Ai with about 1000 g of styrene / butadiene ABA block copolymer at a temperature of about 100 ⁰ C in a Mehrschnittextrudiervorrichtung. The mixture is then at low

- 30 409831/0992

Temperatures triturated to form carrier particles with an average particle size of about 100 λχ. About 99 parts by weight of the carrier particles are mixed with about 1 part by weight of the pressure fixable toner particles of Example VII and the development methodology of Example VII is used. The low density composite backing is found to perform extremely well and the print quality during the test is excellent. The toner impact is extremely low and essentially no carrier wear is observed.

Example IX

Composite particles are formed by heating glass beads an average diameter of about 100U and a composition of about 42.0 % lead oxide, about 5.6 % barium oxide, about 18.3 % titanium dioxide, and about 31.8 % silicon dioxide to a temperature of about 81.6% ° C (15oo ° P) for about 1 hour. The beads are then rapidly cooled. As evidenced by the developed opalescence, the crystallization occurs to a considerable extent. Furthermore, different degrees of crystallinity can be achieved by varying the temperature and / or the time of heating. In general, maximum crystalline development results at a temperature of about 180 ° C. over a period of about 3 hours. A developer mix is created by mixing about 99 parts of the resulting carrier particles with about 1 part of the toner particles of Example I and the development methodology of Example

- 31 409831/0992

I is applied. It is found that the composite beam behaves well and the print quality is good during the attempt. There is essentially no toner impact or carrier wear is observed.

Example X

Composite carrier particles are made by fusing about 1000 grams of lead and about 1500 grams of tin. That Mixture is mixed thoroughly, cooled and formed into spherical carrier particles of average particle size shaped by about 100 / rev. About 99 parts by weight of the resulting carrier particles are mixed with about 1 part by weight of the toner particles of Example I to form a Developer mix mixed and as in the development process of example I used. It is found that the composite carrier performs well and the print quality is good is good during the attempt. Substantially no toner impact or carrier abrasion is observed.

Example XI

Composite support particles are prepared by heating about 1500 grams of 1018 carbon steel particles an average diameter of about 100 Ai in a furnace operated at a temperature of about 427 ° C (800 ° P) with ambient air for about 15 minutes. After cooling, an examination of the

- 32 409831/0992

particles treated in such a way that a thin, adherent film of iron oxide forms over the entire surface of the Carbon steel particles developed. It becomes a developer ge mix by mixing about 99 parts of the resulting carrier particles with about 1 part of the toner particles of Example I using the development procedure of Example VII. It is found that the composite carrier behaves well and the print quality is good during the test. It will be in essentially no toner impact or carrier abrasion observed.

Example XII

Verbundumkehrträgerteilchen low density are prepared by melt blending from about I500 g of iron powder having an average particle diameter of about 1 Ai with about 1000 g tetrafluoroethylene. The mixture is cooled and formed into carrier particles having an average particle diameter between about 90 and about 110 / rev. About 99 parts by weight of the resulting carrier particles are mixed with about 1 part by weight of the pressure-fixable toner particles of Example VII and the development procedure of Example II is followed. The low density composite backing is found to perform exceptionally well and the print quality during the test is excellent. The toner impact is exceptionally low and essentially no carrier wear is observed.

- 33 -409831/0992

- 23 -

Albeit specific materials and conditions in the above examples for manufacture and use of the developer materials according to the invention have been specified, these are used for illustration purposes only the invention. Various other toners, carrier substitutes, and processes, such as those, for example given above may be substituted for those of the Examples with similar results.

409831/0992

Claims (54)

Claims 1. composite carrier particles for electrostatographic - 'image development systems, characterized in that the carrier particles a average diameter between about 50 and about 1000 / U and an integral combination of fine, powdered, ceramic material that is dispersed in a matrix material, represent. 2. Composite carrier particles for electrostatographic image development systems according to claim 1, characterized characterized in that the matrix material is rubber. 3. composite carrier particles for electrostatographic image development systemsehaeh claim 1, characterized characterized in that the matrix material is a plastic material. 4. Composite carrier particles for electrostatographic image development systems according to claim 1, characterized characterized in that the matrix material is a ceramic material. 5. Composite carrier particles for electrostatographic - 35 409831/0992 - 55 - Image development systems according to claim 1, characterized characterized in that the matrix material is a metal. 6. Composite carrier particles for electrostatographic image development systems, characterized in that the carrier particles have an average diameter between about 50 and about 1000 M and represent an integral combination of metal or metal oxide which is dispersed in a matrix material. 7. composite carrier particles for electrostatographic image development systems according to claim 6, characterized characterized in that the matrix material is rubber. 8. Composite support particles for electrostatographic Image development systems according to claim 6, characterized in that the matrix material represents a plastic material. 9. composite carrier particles for electrostatographic image development systems according to claim 6, characterized It is noted that the matrix material is a ceramic material. 10. Composite carrier particles for electrostatographic image development systems according to claim 6, characterized characterized in that the matrix material is a metal. - 56 409831/0992 11. Composite beams for electrostatographic Image development systems according to claim 6, characterized in that the matrix material comprises at least one metal oxide. 12. composite carrier particles for electrostatographic image development systems, characterized in that the carrier particles a have an average diameter between about 50 and about 1000 / U and a metal alloy represent. 13 * composite carrier particles for electrostatographic image development systems, characterized in that the carrier particles have an average diameter between about 50 and about 1000 Ai and comprise two or more physical phases of the same material within the carrier particles. 14. Composite carrier particles for electrostatographic image development systems according to claim I3 * characterized in that the physical phases have two or more dispersed, crystalline phases of the material. 15. Composite carrier particles for electrostatographic image development systems, characterized by g e k e η η, that the porters one average diameter between about 50 - 37 - 409831/0992 - 57 - and have about 1000 λχ and represent steel beads which have a surface layer of carbon. 16. Composite carrier particles for electrostatographic Image development systems, characterized in that the carrier particles have a have an average diameter of between about 50 and about 1000 microns and steel beads, which have a surface layer of nitrogen or a nitrogenous surface layer, represent. 17. Composite carrier particles for electrostatographic image development systems, characterized in that the carrier particles have an average diameter between about 50 and about 1000 ax , and represent steel beads which have a surface layer made of carbon and nitrogen. 18. Composite carrier particles for electrostatographic image development systems, characterized in that the carrier particles have an average diameter between about 50 and about 1000 Ax and represent an integral combination of 2 or more materials which allow the customized cutting or adjustment of the electrostatographic reaction of the carrier particles. - 38 409831/0992 19. An electrostatographic developer mixture, characterized in that it comprises finely divided toner particles which adhere electrostatographically to the surface of composite carrier particles having an average diameter between about 50 and about 1000 Ai , the carrier particles being an integral combination of fine, powdered, ceramic material represent, which is dispersed in a matrix material. 20. Electrostatographic developer mixture according to claim 19, characterized in that that the matrix material is rubber. 21. Electrostatographic developer mix after Claim 19, characterized in that the matrix material is a plastic material represents. 22. Electrostatographic developer mixture according to claim 19, characterized in that that the matrix material is a ceramic material. 23. Electrostatographic developer mix after Claim 19, characterized in that the matrix material is a metal. 409831/0992 24. An electrostatographic developer mixture, characterized in that it comprises finely divided toner particles which adhere electrostatically to the surface of composite carrier particles and the carrier particles have an average diameter between about 50 and about 1000 Ai and an integral combination of metal or metal oxide dispersed in a matrix material , represent. 25. Electrostatographic developer mixture according to claim 24, characterized in that that the matrix material is rubber. 26. Electrostatographic developer mixture according to claim 24, characterized in that that the matrix material is a plastic material. 27. Electrostatographic developer mix after Claim 24, characterized in that that the matrix material is a ceramic material. 28. Electrostatographic developer mixture according to claim 24, characterized in that that the matrix material is a metal. 29. Electrostatographic developer mix after - 40 409831/0992 - 4ο - Claim 24, characterized in that that the matrix material comprises at least one metal oxide. 30. Electrostatographic developer mix, thereby denoted that there are finely divided toner particles that adhere electrostatically to the surface of composite carrier particles, wherein the carrier particles have an average diameter between about 50% and about 1000 / U and a metal alloy represent. 31. Electrostatographic developer mixture g e identifies by finely divided toner particles that adhere electrostatically to the surface of composite carrier particles, the carrier particles have an average diameter between about 50 and about 1000 µ and represent two or more physical phases of the same material within the carrier particles. 32. Electrostatographic developer mix after Claim 31, characterized by » net that the physical phases are two or more dispersed crystalline phases of the material represent. 33. Electrostatographic developer mixture, characterized by finely divided toner particles, the electrostatic on the surface - 41 409831/0992 adhered by composite carrier particles, the carrier particles having an average diameter between about 50 and about 1000 Ai and comprising steel beads having a surface layer of carbon. 34. An electrostatographic developer mixture, characterized by finely-divided toner particles electrostatically adhered to the surface of composite carrier particles, said carrier particles have an average diameter between about 50 and about 1000 M and represent steel beads which have a surface layer of nitrogen or nitrogen containing surface layer. 35. Electrostatographic developer mix, g e k label lean through finely divided toner particles that are electrostatic to the surface adhered by composite carrier particles, the carrier particles having an average diameter between about 50 and about 1000 / rev and represent steel beads having a surface layer of carbon and nitrogen. 36. Electrostatographic developer mixture, characterized by finely divided toner particles, which adhere electrostatically to the surface of composite carrier particles, the carrier particles having an average diameter - 42 - 409831/0992 have a knife between about 50 and about 1000 Ai and comprise an integral combination of 2 or more materials, which enables the tailor-made cutting or the adjustment of the electrostatographic reaction of the carrier particles. 37. An electrostatographic imaging process, characterized by the process steps of providing an electrostatographic imaging element with a recording surface, forming an electrostatic latent image on the surface and contacting the electrostatic latent image with a developer mixture, the finely divided toner particles that adhere electrostatically to the surface of composite carrier particles , wherein the carrier particles have an average diameter between about 50 and about 1000 Ai and represent an integral combination of fine powdered ceramic material dispersed in a matrix material, whereby at least a portion of the finely divided toner particles are attracted to the recording surface according to the electrostatic latent image and then deposited. 38. Electrostatographic imaging method according to Claim 37, characterized in that rubber is used as the matrix material. 39. Electrostatographic imaging method according to claim 37 *, characterized in that 409831/0992 that the matrix material is a plastic material used. 40. Electrostatographic imaging method according to claim 37> characterized in that a ceramic material is used as the matrix material. 41. The electrostatographic imaging method according to claim 37, characterized in that that a metal is used as the matrix material. 42. Electrostatographic imaging, characterized by the process steps of providing an electrostatographic imaging system with a recording surface, forming an electrostatic latent image on the surface and contacting the electrostatic latent image with a developer mixture comprising finely divided toner particles that are electrostatically adhered to the surface of composite carrier particles , wherein the carrier particles have an average diameter between about 50 and about 1000 Ai and represent an integral combination of metal or metal oxides, dispersed in a matrix material, whereby at least a portion of the finely divided toner particles are attracted and deposited on the recording surface in accordance with the electrostatic latent image . 43. Electrostatographic imaging method according to claim 42, characterized in that that rubber is used as the matrix material. 409831/0992 44. Electrostatographic imaging method according to Claim 42, characterized in that the matrix material used is a plastic material used. 45. Electrostatographic imaging method according to Claim 42, characterized in that the matrix material used is a ceramic material used. 46. Electrostatographic imaging method according to claim 42, characterized in that that a metal is used as the matrix material. 47. Electrostatographic imaging method according to Claim 42, characterized in that at least one metal oxide is used as the matrix material used. 48. Electrostatographic imaging process, characterized by the process steps of providing an electrostatographic Imaging element with a recording surface, Formation of an electrostatic latent image on the surface and contacting of the electro-static latent image with a developer mixture, the finely divided toner particles, which are electrostatically adhered to the surface of composite carrier particles, wherein the carrier particles have an average diameter between about 50 and about 1000 / U and a metal alloy represent, whereby at least part of the - 45 - 409831/0992 24Q2982 finely divided toner particles corresponding to the electrostatic latent image on the recording surface attracted and deposited thereon. 49. An electrostatographic imaging process, characterized by the process steps of providing an electrostatographic imaging element with a recording surface, forming an electrostatic latent image on the surface and contacting the electrostatic latent image with a developer mixture which comprises finely divided toner particles which adhere electrostatically to the surface of composite carrier particles , wherein the carrier particles have an average diameter between about 50 and about 1000 M and represent two or more physical phases of the same material within the carrier particles, whereby at least a portion of the finely divided toner particles are attracted to and deposited on the recording surface in accordance with the electrostatic latent image . 50. The electrostatographic imaging method according to claim 49, characterized in that that two or more dispersed crystalline phases of the material are used as physical phases. 51. Electrostatographic imaging process, identified through the procedural stages the provision of an electrostatographic imaging member having a recording surface, formation of an electrostatic latent Image on the surface and contacting 409831/0992 -46- the electrostatic latent image with a developer mixture, the finely divided toner particles that are electrostatically attached to the surface of composite carrier particles adhere, wherein the carrier particles have an average diameter between about and about 1000 / U and steel beads that have a Have surface layer made of carbon, represent, whereby at least a part of the finely divided toner particles is attracted to the recording surface according to the electrostatic latent image and be deposited thereon. 52. Electrostatographic imaging process, characterized by the process steps the provision of an electrostatographic imaging element having a recording surface, Formation of an electrostatic latent image on the surface and contacting of the electrostatic latent image with a developer mixture, the finely divided toner particles, which are electrostatic adhering to the surface of composite carrier particles, wherein the carrier particles comprise a Average diameter between about 50 and about 1000 / U and steel beads that form a surface layer of nitrogen or nitrogen-containing surface layer, represent, whereby at least a part of the finely divided toner particles corresponding to the electrostatic latent image the recording surface are attracted and deposited thereon. 53 Electrostatographic imaging process, characterized by the process 409831/0992 - 47 - steps of providing an electrostatographic imaging member with a recording surface, forming an electrostatic latent image on the surface and contacting the electrostatic latent image with a developer mixture comprising finely divided toner particles which adhere electrostatically to the surface of composite carriers, the carrier particles having an average diameter between about 50 and about 1000 Ai and steel beads which have a surface layer of or with carbon and nitrogen, whereby at least a part of the finely divided toner particles are attracted and deposited on the recording surface in accordance with the electrostatic latent image. 54. Electrostatographic imaging process, characterized by the process stages the provision of an electrostatographic imaging element having a recording surface, Formation of an electrostatic latent image on the surface and contacting of the electrostatic latent image with a developer mixture, the finely divided toner particles, which are electrostatic adhering to the surface of composite carrier particles, wherein the carrier particles have an average Diameter between about 50 and about 1000 / rev and represent an integral combination of two or more materials appropriate to the dimensionally accurate Cutting or adjustment of the electrostatographic reaction of the carrier particles allows, - 48 40 983 1/0992 whereby at least a part of the finely divided toner particles corresponding to the electrostatic latent Image attracted to the recording surface and deposited thereon. 409831/0992