CA1160497A - Fluorinated carbon-containing developer composition - Google Patents
Fluorinated carbon-containing developer compositionInfo
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- CA1160497A CA1160497A CA000378122A CA378122A CA1160497A CA 1160497 A CA1160497 A CA 1160497A CA 000378122 A CA000378122 A CA 000378122A CA 378122 A CA378122 A CA 378122A CA 1160497 A CA1160497 A CA 1160497A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G9/00—Developers
- G03G9/08—Developers with toner particles
- G03G9/09—Colouring agents for toner particles
- G03G9/0902—Inorganic compounds
- G03G9/0904—Carbon black
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Abstract
ABSTRACT
A flowable, dry powder of particles of a developing composition are provided. The compositions may be either heat or pressure-fixable and utilize from about 0.4 to 3 parts by weight of fluorinated carbon per 100 parts by weight of a thermoplastic binder and a magnetically responsive material. The fluorinated carbon has a degree of fluorination in the range of 10% to 63%
and an average diameter below about 2 microns. The developing powder compositions possess improved flow humidity resistance and provide dramatically improved copy quality.
A flowable, dry powder of particles of a developing composition are provided. The compositions may be either heat or pressure-fixable and utilize from about 0.4 to 3 parts by weight of fluorinated carbon per 100 parts by weight of a thermoplastic binder and a magnetically responsive material. The fluorinated carbon has a degree of fluorination in the range of 10% to 63%
and an average diameter below about 2 microns. The developing powder compositions possess improved flow humidity resistance and provide dramatically improved copy quality.
Description
~ 9 7 159,939 CAN/JVL
FLUORINATED CARBON-CONTAINING DEVELOPER COMPOSITION
Background of the Invention This invention relates to dry powder compositions suitable for use in electrographic recording. More particularly, it relates to heat fusible and pressure fixable one part developing powders that contain fluorinated carbon.
Known one-part developing powder formulakions used in electrographic recording may be either heat fusible or pressure fixable. Heat fusible developing powders are typically fixed after image ormation by raising the temperature of the powder to its melting or softening point, causing the powder particles to coalesce, Elow together, and adhere to the substrate. Pressure fixable developing powders are typically fixed after image ~ormati~n by simply applying pressure to the powder particles causing them to coalesce and adhere to the substrate.
Although both types of developing powders have ,'(~ b~n widely used and have enjoyed commercial success, they suffer from certain disadvantages that are related to their physical characteristics.
For example, the flow properties and developing characteristics of such powders are affected by the nature of the carbon black used. It has been found that if electrically resistive carbon black is employed, the powder has poor flow properties (i.e., it c~kes and resists Elow), especially in conditions oE high humidity.
Generally, the images produced with such powders have poor resolution, that is they exhibit fuzzy edge definition and image "fill-in" (i.e., toner deposits inside of letters such as A, B, D, O).
Additionally~ such powders requently orm clumps in conditions of high humidity that may result in streaking on the finished copy. Still further, such powders are susceptible to clogging in the development .
~ 1 6~97 station leading to poor development and transfer of the developing powder and consequently, poor copy quality.
Developing powders that employ conductive carbon-black also demonstrate poor flow properties and produce images that have poor resolution. Moreover, only low concentrations ~e.g., about 0.5% by weight) of such carbon black can be utilized if an electrically resistive developing powder is desired. However, low carbon black concentrations are difficult to incorporate uniformly into the powder. Moreover, electrically conduc~ive carbon black is hydrophilic in nature and this aggravates the poor Elow properties of the developing powder compositions~
The foregoing disadvantages are overcome in the present invention. This is accomplished through the incorporation of fluorinated carbon into the developing powder composition.
Summary of the Invention In accordance with the present invention there ~0 is provided a Elowable, dry powder of particles that has a static conductivity of less than about 10 3 (and preferably less than about 10 10) ohm 1 centimeter 1 in an electric field of 10,000 d.c. volts per centimeter. The dry powder comprises (a) from about 30 to 80 (and preferably from about 35 to 45) parts by weight of a thermoplastic hinder that has a static conductivity of at most 10-12 ohm 1 centimeter 1, said binder being selected from the group consisting of waxes that have a melting point in the range 30 of about 45C to 150C (preferably between about 65C and 125C), organic resins that have a softening point above about 60C (preferably between about 120C and 200C), and mixtures oE said waxes and resins; and correspondingly, from about 70 to 20 (and preferably from about 65 to 55) parts by weight of a magnetically responsive material; and 1 1 ~0~97 (b) from about 0.4 to 3 parts by weight per 100 parts by weight of (a) of fluorinated carbon that has a degree of fluorination in the range of 10% to 63~ (based upon the weight of the carbon) and an average diameter below about 2 microns, and preferably below about 100 millimicrons wherein said fluorinated carbon comprises a radially dispersed layer or zone around the outer portions of the powder particles.
Preferably the fluorinated carbon preferably comprises from about 0.75 to 3 par s, and most preferably from about 0.75 to 1.5 parts, by weight per lO0 parts by weight of (a), and is ~rom about 15% to 30% fluorinated.
That static conductivity referred to herein is measured according to the technique described at column 3, line 54 through column 4, line 47 of U.S. Patent 3,639,245. The melting point referred to above is measured according to ASTM: D-1~7, while the ring and ball soEtening point is measured according to ASTM:E28.
The powder of the present invention preferably comprises essentially spherical particles wherein at least 95 number percent of the particles have a maximum dimension in the range of about 4 to 30 microns.
The developing powder of the present invention possesses improved flow properties and provides high resolution images. It does not signiEicantly cake together even in conditions of high humidity. The images produced from the powder are uniform, have sharp edge definitionr and exhibit virtually no image fill-in. Still Eurtller, backgrounding i.e., background coloration caused by random deposition of developing powder particles in non-image areas, is substantially reduced.
These results are achieved through the use of fluorinated carbon to at least partially replace standard (i.e., non-fluorinated~ carbon black. Fluorinated carbon is less conductive than equivalent non-fluorinated carbon black. Conse~uently, a higher percentage by weight of the fluorinated carbon can be employed to achieve a given 1 1 6~197 --D~
conductivity, thereby providing better uniformity in the final developing powder. Additionally, fluorinated carbon is hydrophobic so that th~ developing powders of the invention are less susceptible to the effects of moisture than are developing powders that employ standard carbon.
Still further, the developing powder cornposi-tions of the invention become more negatively charged during the copying process than do equivalent developing powders that employ standard carbon. It is believed that this proper~y accounts at least in part for the ability oE
the developing powder compositions of the invention to provide such high resolution imagesr Although the use of fluorinated carbon in developing powder compositions has been suggested, see, for example U.S. Patent 4,141,849 and Japanese application JA54-19343 published September 8, 1976, the present invention represents an improvement thereover. These publications each disclose the use of graphite fluoride in two part developing powder compositions (i.e., those that comprise a toner powder and a separate carrier~. The U.S.
Patent specifies a minimum degree of fluorination of 50%, while the Japanese application specifies a degree of fluorination in the range of 1 to 150%, based upon the weight of the carbon. However, it has been found that such two part developing powder compositions are not satis~actory. For example, such powders must rely on the carrier particles to remove the toner powder from non-charged areas. Frequently, the carrier does not do an effective job of this thereby giving rise to a significant level of backgrounding. Furthermore, the developed images are frequen-tly hollow, that is, solid areas are not filled in, resulting in low fidelity development. Additionallyr copy quality degrades with time when two part developing powder compositions are employed. This requires that the developing composition be purged and replaced by fresh material. The developing powder composition o~ the present invention alleviates these problems.
1 ~ 6~7 Brief Description of The Drawings The present invention will be better understood by reference to the accompanying drawings wherein like reference numbers refer to the same elements throughout the several views, and wherein each drawing is a photomicrograph at 8X magnification. In the drawings Figures 1 and 2 represent separate photomicrograph~ of copies of a graphic original containing both typed and preprinted portion~. The copy in Figure 1 was made using a heat usible developing powder of the invention~ while the copy in Figure 2 was made using a standard heat fusible developing powder.
Both copies were made by a conventional heat fusing copying process.
Figures 3 and 4 represent separate photo-micrographs of copies of a graphic original containing preprinted areas. The copy in Figure 3 was prepared using a pressure fixable developing toner powder of the invention, while the copy in Figure 4 was prepared using a standard pressure fixable developing powder. Both copies were made by a conventional pressure fixing copying process.
Detailed Description of the Invention Referring specifically to Figures 1 and 2, there are shown portions of electrostatic copies prepared using heat fusible developing powders and conventional copying processes. These Figures contain unmagnified typed areas 10 and 20; corresponding magnified typed areas lOA and 20A; unmagniEied preprinted areas 11 and 21; and corresponding magnified preprinted areas llA and 21A.
As can be seen by reference ko areas lOA and llA
o~ Figure 1, typed characters 12A and preprinted characters l3A do exhibit excellent resolution. They have well de~ined edges 14A and virtually no image fill-in, see 15A. Additionally, the copies exhibit virtually no back-grounding, see 16A.
1 1 60~97 The signiEicant improvement in copy quality is shown by comparison of Figures 1 and 2. Thus, neither typed characters 22A nor preprinted characters 23A exhibit good resolution. To the contrary, the characters have fuzzy edges 24A and a signiEicant level of image-fill in, see 25A. Furthermore, the copies exhibit a high degree of backgrounding, see 26A.
A comparison of Figures 3 and 4 further demon-strates the significant improvement in copy quality achieved by the developing powders of the present inven-tion. These Fiyures contain magnified areas 30A and 40A.
The characters 31A in Figure 3 have sharper edges 32A, substantially less image fill-in as shown at 33A than do characters 41A in Figure 4. Compare, for example edges 42A and areas 43A of Figure 4. Moreover, characters 31A are more uniformly toned than are characters 41A. See especially the a, c, d, and e.
Still further, the copy illustrated in Figure 3 demonstrates substantially less backgrounding than does ~o the co~y illustrated in Figure 4. Compare especially areas 34A of Figure 3 with areas 44A of Figure 4.
These surprising results are achieved as a result oE the use of fluorinated carbon in the developin~
powder composition of the invention. The fluorinated carbon useful in the invention comprises an in~rganic compo~nd made up oE carbon chemically bonded to 1uorine by covalent bonds. The fluorinated carbon may comprise ~luorinated graphite (natural or artificial) or, alternatively, fluorinated petroleum coke, coal coke, charcoal, carbon black, and mixtures thereof. Such A materials are known as shown by, for example, "Cermatic", 4(301) 1969; Denki Kagaku, 51, 756-761, 1963; Denki Kagaku, 35, 19-23, 1967.
Processes for the preparation of fluorinated carbon are known. For example, see "Cermatic", supra, and other references. Other process for the preparation of fluorinated carbon involve the direct fluorination of T,O,~Je ~,~
~ 3 6~9~
carbon at temperatures varying Erom ambien~ to over 450C.
Fluorination is preferably carried out in an agitated reactor in an atmosphere of fluorine plus an inert gas, although a non-agitated reactor may be employed if desired.
The conditions utilized during fluorination in a agitated reactor may be varied so as to obtain the desired degree of fluorination. Examples of such conditions, and the degree of fluorination obtained, are set forth in hO Table 1. The carbon used to obtain the data for this Table was Vulca ~ XC 72R, a conductive carhon black with a maximum particle size of 30 millimicron sold by Cahot Corporation.
FL~ORINATION CARBON BhK RXN TIME RXN TEMP FLUORINE
(%) (~) _(hrs)(C) (cc/min) 5.5 7.0 2.2Amhient ~0-52 15.~ l6.5 ~ 0-~10 5-16 20.9 26.3 2200-205 50 24.6 22.7 7150-195 50 31.6 17.6 6.7185-20~ 11 Other carbon materials may also be used in the present i~vention. Representative of such materials are Conductex~950 (maximum particle si~e o~ 21 millimicron) sold by Cities Service, Raven 1800 (Inaximum particle size of 18 millimicron) sold by Columbia Chemicals, Ketjenblack EC sold by Noury, and Thermax MT sold by R. T~ Vanderbilt.
The thermoplastic binder useul in the present invention has a static conductivity as set forth above and i~ selected from waxes that have a melting point in the range of 45C to 150C and organic resins that have a ring and ball softening point above about 60C. Waxes useEul in the invention are normally selected from the group consisting of aliphatic compounds such as waxes ~natural or synthetic), fatty acids, metal salts o Eatty acids, Je ~L~
11 1 6~9~
hydroxylated fatty acids or amides, low molecular weight ethylene homopolymers, or a mixture of -two or more of these materials. Aromatic and polymeric wax-like materials can also be used. All of these materials are well known in the art.
Representative useful aliphatic waxes include paraffin wax, microcrystalline wax, caranauba wax, montan wax, ouricury wax, ceresin wax, candellila wax, and sugar cane wax.
Representative useful ~atty acids include stearic acid, palmitic acid, and behenic acid.
Representative useful metal salts of fatty acids include aluminum stearate, lead stearate, barium stearate, magnesium stearate, zinc stearate, lithium stearate, and zinc palmitate. Representative amide hydroxy waxes include N(betahydroxyethyl)-ricinoleamide ~commercially available under the trade name "Flexricin 115"), N,N'ethylene-bis-ricinoleamide (commercially available under the trade name "Flexricin 185"), N(2-hydroxyethyl)-12-hydroxystearamide (commercially available under the trade name "Paracin 2~0"), and N r N'-ethylene-bis-12-hydroxystearamide (commercially available under the trade name 'IParacin 285").
Representative fatty acid derivatives include castor wax (glyceryl tris-12-hydroxy stearate) r methyl hydroxy stearate tcommercially available under the trade nalne "Paracin 1"), ethylene glycol monohydroxy stearate (commercially available under the trade name "Paracin lS") and hydroxy stearic acid.
Representative ethylene homopolymers include the low molecular weight polyethylenes such as the Bareco Polywaxes such as Polywax 655, 1000, and 2000 sold by the Bareco Division of Petrolite Corporation. Other ethylene homopolymers include oxidized, high density, low molecular weight polyethylenes such as Polywax E-2018 and E-2020 sold by Bareco Division of Petrolite Corporation; and the Epolene~ series of low molecular weight polyethylene t ~ 6~97 g resins such as Epolene~ E-14 available from Eastman Chemical Products Incorporated.
Representative useful aromatic wax-like materials include dicyclohexylphthalate, diphenylphthalate and the Be Square series of waxes from the Bareco Division of Petrolite Corporation, such as Be Square 195~ The Be Square waxes are high melting point waxes that consist of paraffines and naphthenic hydrocarbons.
Representative of organic resins useful as the thermoplastic binder are the polyamides (e.g., "Versamid 950", commercially available from General Mills);
polystyrenes (e.g., 2000 mol. wt.); bisphenol A epoxy resins (e.g., "Epon~1004", commercially available fro~
Shell Chemical Corp); acrylic resins ~e.g., "Elvacite 2044", and N-bu~yl methacrylate commercially available from DuPont); vinyl resins such as polyvinyl butyral (e.g., "Butvar~B72-A," commercially available from Monsanto Company), polyvinyl acetates (e.g., "Gelva V-100", commercially available from Monsanto Company);
vin~l copolym~rs such as vinyl chloride/vinyl acetate (e.g., "VYHH", commercially available from Union Carbide Corp.), ethylene/vinyl acetate copolymers; cellulose este~s such as cellulose acetate butyrate (e.g., "EAB-171-25", commercially available from Eastman Chemical Products~ Inc.), cellulose acetate propionate (e.g., "CAPPLES~70", commercially available from Celanese Corp.);
and cellulose ethers.
When a heat fusible developing powder is L~r~ar~cl the thermoplastic binder preEerably cornprises the organic resin. Most preferably the organic resin has a softening point between about 120C and 200C and comprises a bisphenol A epoxy resin.
When a pressure fixable developing powder is prepared, the thermoplastic binder may comprise either the wax or a combination o the wax and the organic resin.
Preferably the weight ratio of organic resin to wax is in the range of about 0:1 to 1:1. Most preferably ratio is ~ 1 6(~9~
about 0:1. In either event, the wax preferably is selected Erom a microcrystalline wax, a low molecular weight polyethylene resin, or a combination of both, while the organic resin, when present/ comprises a bisphenol A
epoxy resin.
The magnetically responsive material employed in the developing powder composition preferably is homo--geneously distributed throughout the binder.
Additionally, it preferably has an average major dimension of one micron or less. Representative examples o~ useful ma~netically responsive materials include magnetite, barium ferrite, nickel zinc ferrite, chromium oxide, nickel oxide, etc.
Various other materials may also be usefully incorporated in or on the developer composition particles of the present invention. Such materials include, for example, colorants such as powdered flow agents, piyments and, dyes, plasticizers, etc.
Representative po ~ered flow agen-ts inclue small size SiO2 such as "Cab-~ Sil" sold by the Cabot Corporation and "Aerosil" R-972 sold by the DeGussa Corporation.
Representative colorants are carbon blacks, particularly conductive carbon blacks. These may be used in conjunction with the fluorinated carbon employed in the invention.
'l'he developing powders of the invention may be prepared by known processing techniques. Thus, for example, heat fusing developing powders may be prepared by the techniques described in U.S. Patent 3,639,245 at column 5, lines 3 to 36. Pressure fixable developing powders may be prepared by the techniques described in U.S. Patent 3,925,219 at column 4, lines 25-59.
Preferably the powder particles are spherical.
In these processes, the fluorinated carbon is incorporated into the developing powder in the same fashion as is the conductive particles referred to therein. The resultant powder possesses a radially dispersed layer or zone o electrically conductive carbon.
The present invention is further illustrated by means of the following examples wherein the term "parts"
refers to parts by weight unless otherwise indicated.
Heat-fusible developing powders were prepared using the ingredients and amounts shown:
INGREDIENTS PARTS
la lb "EPON" 1004 (Epichlorohydrin/
Bisphenol A solid epoxy resin, melting point 95-105C, epoxy equivalent weight 875-1,025, molecular weight o~ 1400 a trademarked product oE Shell Chemical Company) 40 4Q
MAGNETITE (Cities Service Corporation) 60 60 FLUORINATED CARBON ( 29.6% fluorinated 1.3 ~-Vulcan XC-72R from the Cabot Corporation) ~0 NON-FLUORINAT~D CARBON (VULCAN XC-72R) -- 0.53 The "Epon" and the Magnetite were blended thoroughly on a conventional heated-roll rubber mill. The resulting blend was pulverized in an attrition-t~pe grinder and then classified in a standard air centrifugal type machine. These particles were sharp edged and pseudocubical in shape. They were spheroidized such that most of the particles were transformed into sphere like shapes or round-edged particles by the Eollowing process.
'l'he mixture was fed to an air aspirator in a uniform stream o~ about 800 grams per hour. The aspirator sucked the particles into the air stream and dispersed them ~orming an aerosol. The aerosol was directed at 90 into a heated air stream the temperature of which was about 510-540C. The powder was then allowed to settle and was collected by filtration.
The spheroidized particles were combined with either the fluorinated or the non-Eluorinated carbon and then blended first at room temperature for 3 hours and then at 65C for about 8 hours~ The carbon was then radially dispersed or embedded into the resin by the spheroidization process described above except that the temperature of the hot air stream was adjusted to 650C
and the powder was fed to the air stream at a rate of about 36 ]cilograms per hour. The resultant developing powder compositions were collected and classifled so that 95% by weight o the product was greater than 6.5 microns average diameter and only 5% by weight was greater than 19 microns average diameter.
The final step in the process was to blend 0.05 parts per hundred parts of developing powder composition of a small size SiO2 flow ayent (i.e., Aerosil R-972 sold by the DeGussa Corporation with the composition. The resultant compositions were tested for static conductivity. The results are given in Table 2.
Example Carbon Static Conductivity (Mhos/cm) _ 1000 v/cm -15 la Fluorinated 2.3 x 10 lb non-fluorinaged 2.7 x 10 15 This data demonstrates that the use of fluorinated carbon enables a larger quantity of conductive material to be employed in the developing powder composi-tions in order to achieve a given static conductivity.
This in turn provide~ improved flow characteristics even under conditions of high humidity.
116~)~97 Each of the developing powder compositions was used in a conventional heat-fusing copying process to provide images on a plain paper substrate. The developiny powder composition of Example la provided copies with images that were sharply defined and had virtually no image fill-in. Additionally there was virtually no hackgrounding. A photomicrograph of a copy prepared from the powder of Example la, is shown in Figure 1. The developing powder composition of Example lb provided copies with images that were not sharply defined and had substantial amounts of image fill-in. Furthermore, there was a ~ignificant degree of backgrounding~ A photomicro-graph of a copy prepared from the powder of Example lb is shown in Figure 2.
A heat-fusible developing powder composition was prepared as described in Example 1 except that embedment was carried out at 430C. The following ingredients and amounts shown were used.
"EPON" 1004 40 FLUORINATED CARBON
(63~ Fluorinated Graphite sold by Air Products and Chemicals, Inc.) 0.57 NON-FLUORINATE~ CARBON (Vulcan XC-72R) 0.57 The resultant developiny powder composition was classiEied so that 95% by weight of the powder was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivity of the developing powder was 2.8 x 10 15 mhos/cm in a 10,000 volt/cm d.c. field~ The developing powder was used in a heat-fusing copying process to provide a copy with well defined images and virtually no 9 ~
image fill-in or backgrounding on a plain paper substrate.
Example 1 was repeated except that embedment was carried out at about 430C. In Example 3a, 0.49 parts by weight of fluorinated Vulcan XC-72R (8.4% fluorination) was employed, while in Example 3b, 0.42 parts by weight of non-fluorinated Vulcan XC-72R was used. The static conductivity of the resultant developing powder composi-tions is reported in Table 3.
Example Carbon Black Static Conductivity (mhos/cm) _ _ 000 v/cm 15 3a fluorinated 5.5 x 10 15 3b non-fluorinated 9.0 x 10 1 When each of these compositions was employed in a heat fixing copying process to produce images on a plain paper substrate, no difEerence could be seen between ~he quality of the copies produced. Thus, in each case the images had poor edge definition and a fair degree of image fill in. Consequently, this example demonstrates that the fluorinated carbon must have a degree of fluorination of at least 10~.
EXAMP~E ~
Pressure-fixable developing powders were prepared using the following ingredients in the amounts stated:
1 .~ 6~g7 PARTS
INGREDIEN~S 4a 4b ~OLYW~X E2018 (Oxidi~ed hi~h density, 10 10 molecular weight polyethylene sold by Bareco Division of Petrolite Corporation) BE SQUARE 195 (Hard microcrystalline was 30 30 sold by sareco Division of Petrolite Corporation) 10 FLUORINATED CARBON (29.4% fluorinated 108 Conductex 950 from Columbia Carbon) ~ION-F1UORINATED CARBON (Conductex 950) -- 1.8 The Polywax and the Be Square were first heated to melting after which the magnetite was added, with stirring, and heated until a homogeneous dispersion was obtained. The temperature of the dispersion was raised to l93C and then sprayed through a nozzle at a rate of about 91 kg/hr to form discrete particles. The particles were classified so that 95% by weight were greater than 6.5 microns and no more than 5% by weight were greater than 20 microns in average diameter.
The substantially spherical particles were then combined with the fluorinated or non-fluorinated carbon black and blended for 3 hours at room temperature. The particles were then spheroidized and the carbon embedded therein as described in Example 1. Embedment was carried out at about 430C.
The developing powder compositions were then classified so that 95% by weight of the powder was greater than 6.5 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivities of these developing powder compositions were measured and are reported in Table 4.
Example Carbon Black Static Conductivity (Mhos/cm) _ 10,000 v/cm 4a Fluorinated 2 x lO
4b Non-fluorinated >lO 4 Ea~h of the developing powder compositions was used in a pressure~fixing copying process to provide i~ages on a plain paper substrate. The developing powder composition of Example 4a provided copies whose images were sharply defined and had virtually no image fill-in.
Moreover, the copies had virtually no backgrounding. A
photomicrograph of a copy prepared using the developing 15 powder of Example 4a is shown in Figure 3. The developing powder composition of Example 4b, on the other hand, provided copies whose images had poor edge definition and a high degree oE image fill-in. Additionally, the background areas of the copies produced ~rom the 20 developing powder composition of Example 4b had a high degree of backgrounding. A photomicrograph of a copy prepared using the developing powders of Example 4b is shown in Figure 4.
~XAMPLE 5 Example 4 was repeated except that Vulcan XC-72R
(l.6 parts by weight) that had a degree o~ ~luorination oE
20.~% was utilized in Example 5a and 0.62 parts by weight of non-fluorinated Vulcan XC-72R was used in Example 5b.
The developing powder compositions were classified so that 95~ by weight o~ the powder was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivity of the resultant developing powder compositions is reported in Table 5.
~ 1 6~9~
Example Carbon Black Dynamic Conductivity (Mhos/cm~
10,000 v/cm _ _ _ _ 5a Fluorinated 2 x 10 5b non-fluorinated 3 x 10 10 Each of the developing powder compositions was used in a pressure-fixing copying process to provide images on a plain pap~r ~ubstrate. The developing powder composition o~ Example 5a provided copie~ whose images were sharply defined and had virtually no image fill-in.
The copies exhibited little backgrounding. The developing powder composition of Example 5b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies exhibited substantial backgrounding.
Example 4 was repeated using the following ingredients in the amounts shown:
INGREDIENTS PARrrS
6a 6b 13E SQ~ E 195 30 30 FLUORINATE~ CARBON ( Vulcan XC-72R, 13.8% fluorination) 1.24 --NON-FLUORINATED CARBON ( Vulcan XC-72R) -- 0.62 The developing powder compositions were classi-fied so that 95~ by weight of the powder was greater than 8 microns average diameter and only 5~ by weight was greater than 20 microns average diameter. The st~tic conductivity of the resultant developing powder composi-tions i5 reported in Table 6.
~16~97 TABL~ 6 Example Carbon Black Static Conductivity (Mhos/cm) 5 ___ 10,000 v/cm 6a Fluorinated 8 x 10 ll 6b non-fluorinated 3 x 10 10 Each of the developing powder compositions was used in a pressure fixing copying process to provide images on a plain paper substrate. The developing powder composition of Example 6a provided copies whose images were sharply defined and had virtually no image fill-in.
The copies exhibited lit~le backgrounding. The developing powder composition of Example 6b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies also exhibited substantial backgrounding.
Example 4 was repeated using the following ;~n ingredients in the amounts shown:
I NGREDI ENT . P RTS
7a 7b POLYWAX 1000 (A low molecular weight, unmodified homopolymer o ethylene having 25 a MW/Mm of 1.2 sold by Bareco Division of Petrolite Corp.) 42 42 FLUORINATED CARBON (25.6% fluorinated Vulcan XC-72R~ 1.54 --NON-FLUORINATED CARBON (Vulcan XC-72R) -- 0.62 The resultant developing powder compositions were collected and classified so that 95~ by weight of the products was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average 1 1 B~9~
diameter. The dynamic conductivities of the resultant compositions are reported in Table 7.
Example Carbon Dynamic Conductivity (mhos/cm~
__ _ _ 10,000 v/cm 7a Fluorinated l.9 x lO lS
7b Non-Fluorinated 1.5 x lO 15 Each of the developing powder compositions was used in a heat-fusing copy process to provide images on a plain paper substrate. The developing powder compositi on of Example 7a provided copies whose images were sharply de~ined and had virtually no image fill-in. The copies exhibited very little backgrounding. The developing powder composition of Example 7b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies also exhibited substantial backgrounding.
A pressure-fixable developin~ powder was prepared as described in Example 4 using the following in~redient.s in the amounts shown:
I REDIENTS PARTS_ _ EPOLENE~ E-14 ( emulsifiable low molecular weight polyethylene resin available from Eastman Chemical Products, Incorporated) 30 30 FLUORLNATED CARBON (25.6% fluorinated Vulcan XC-72R) 1.05 1 1 60~97 The resul~ing developiny powder composition was collected and classified so that 95% by weight of the product was greater than 9 minus average diameter and only 5% by weight was greater than 22 microns averaye diameter.
The composition had a dynamic conductivity of 5.3 x 10 13 Mhos/cm in a 10,000 volt/cm electric fold. The composition was used in a heat Eusing copy process one claim per substrate and provided copies whose images were sharply defined and exhibited virtually no image fill-in, Furthermore, the copies exhibited very little backgrounding.
FLUORINATED CARBON-CONTAINING DEVELOPER COMPOSITION
Background of the Invention This invention relates to dry powder compositions suitable for use in electrographic recording. More particularly, it relates to heat fusible and pressure fixable one part developing powders that contain fluorinated carbon.
Known one-part developing powder formulakions used in electrographic recording may be either heat fusible or pressure fixable. Heat fusible developing powders are typically fixed after image ormation by raising the temperature of the powder to its melting or softening point, causing the powder particles to coalesce, Elow together, and adhere to the substrate. Pressure fixable developing powders are typically fixed after image ~ormati~n by simply applying pressure to the powder particles causing them to coalesce and adhere to the substrate.
Although both types of developing powders have ,'(~ b~n widely used and have enjoyed commercial success, they suffer from certain disadvantages that are related to their physical characteristics.
For example, the flow properties and developing characteristics of such powders are affected by the nature of the carbon black used. It has been found that if electrically resistive carbon black is employed, the powder has poor flow properties (i.e., it c~kes and resists Elow), especially in conditions oE high humidity.
Generally, the images produced with such powders have poor resolution, that is they exhibit fuzzy edge definition and image "fill-in" (i.e., toner deposits inside of letters such as A, B, D, O).
Additionally~ such powders requently orm clumps in conditions of high humidity that may result in streaking on the finished copy. Still further, such powders are susceptible to clogging in the development .
~ 1 6~97 station leading to poor development and transfer of the developing powder and consequently, poor copy quality.
Developing powders that employ conductive carbon-black also demonstrate poor flow properties and produce images that have poor resolution. Moreover, only low concentrations ~e.g., about 0.5% by weight) of such carbon black can be utilized if an electrically resistive developing powder is desired. However, low carbon black concentrations are difficult to incorporate uniformly into the powder. Moreover, electrically conduc~ive carbon black is hydrophilic in nature and this aggravates the poor Elow properties of the developing powder compositions~
The foregoing disadvantages are overcome in the present invention. This is accomplished through the incorporation of fluorinated carbon into the developing powder composition.
Summary of the Invention In accordance with the present invention there ~0 is provided a Elowable, dry powder of particles that has a static conductivity of less than about 10 3 (and preferably less than about 10 10) ohm 1 centimeter 1 in an electric field of 10,000 d.c. volts per centimeter. The dry powder comprises (a) from about 30 to 80 (and preferably from about 35 to 45) parts by weight of a thermoplastic hinder that has a static conductivity of at most 10-12 ohm 1 centimeter 1, said binder being selected from the group consisting of waxes that have a melting point in the range 30 of about 45C to 150C (preferably between about 65C and 125C), organic resins that have a softening point above about 60C (preferably between about 120C and 200C), and mixtures oE said waxes and resins; and correspondingly, from about 70 to 20 (and preferably from about 65 to 55) parts by weight of a magnetically responsive material; and 1 1 ~0~97 (b) from about 0.4 to 3 parts by weight per 100 parts by weight of (a) of fluorinated carbon that has a degree of fluorination in the range of 10% to 63~ (based upon the weight of the carbon) and an average diameter below about 2 microns, and preferably below about 100 millimicrons wherein said fluorinated carbon comprises a radially dispersed layer or zone around the outer portions of the powder particles.
Preferably the fluorinated carbon preferably comprises from about 0.75 to 3 par s, and most preferably from about 0.75 to 1.5 parts, by weight per lO0 parts by weight of (a), and is ~rom about 15% to 30% fluorinated.
That static conductivity referred to herein is measured according to the technique described at column 3, line 54 through column 4, line 47 of U.S. Patent 3,639,245. The melting point referred to above is measured according to ASTM: D-1~7, while the ring and ball soEtening point is measured according to ASTM:E28.
The powder of the present invention preferably comprises essentially spherical particles wherein at least 95 number percent of the particles have a maximum dimension in the range of about 4 to 30 microns.
The developing powder of the present invention possesses improved flow properties and provides high resolution images. It does not signiEicantly cake together even in conditions of high humidity. The images produced from the powder are uniform, have sharp edge definitionr and exhibit virtually no image fill-in. Still Eurtller, backgrounding i.e., background coloration caused by random deposition of developing powder particles in non-image areas, is substantially reduced.
These results are achieved through the use of fluorinated carbon to at least partially replace standard (i.e., non-fluorinated~ carbon black. Fluorinated carbon is less conductive than equivalent non-fluorinated carbon black. Conse~uently, a higher percentage by weight of the fluorinated carbon can be employed to achieve a given 1 1 6~197 --D~
conductivity, thereby providing better uniformity in the final developing powder. Additionally, fluorinated carbon is hydrophobic so that th~ developing powders of the invention are less susceptible to the effects of moisture than are developing powders that employ standard carbon.
Still further, the developing powder cornposi-tions of the invention become more negatively charged during the copying process than do equivalent developing powders that employ standard carbon. It is believed that this proper~y accounts at least in part for the ability oE
the developing powder compositions of the invention to provide such high resolution imagesr Although the use of fluorinated carbon in developing powder compositions has been suggested, see, for example U.S. Patent 4,141,849 and Japanese application JA54-19343 published September 8, 1976, the present invention represents an improvement thereover. These publications each disclose the use of graphite fluoride in two part developing powder compositions (i.e., those that comprise a toner powder and a separate carrier~. The U.S.
Patent specifies a minimum degree of fluorination of 50%, while the Japanese application specifies a degree of fluorination in the range of 1 to 150%, based upon the weight of the carbon. However, it has been found that such two part developing powder compositions are not satis~actory. For example, such powders must rely on the carrier particles to remove the toner powder from non-charged areas. Frequently, the carrier does not do an effective job of this thereby giving rise to a significant level of backgrounding. Furthermore, the developed images are frequen-tly hollow, that is, solid areas are not filled in, resulting in low fidelity development. Additionallyr copy quality degrades with time when two part developing powder compositions are employed. This requires that the developing composition be purged and replaced by fresh material. The developing powder composition o~ the present invention alleviates these problems.
1 ~ 6~7 Brief Description of The Drawings The present invention will be better understood by reference to the accompanying drawings wherein like reference numbers refer to the same elements throughout the several views, and wherein each drawing is a photomicrograph at 8X magnification. In the drawings Figures 1 and 2 represent separate photomicrograph~ of copies of a graphic original containing both typed and preprinted portion~. The copy in Figure 1 was made using a heat usible developing powder of the invention~ while the copy in Figure 2 was made using a standard heat fusible developing powder.
Both copies were made by a conventional heat fusing copying process.
Figures 3 and 4 represent separate photo-micrographs of copies of a graphic original containing preprinted areas. The copy in Figure 3 was prepared using a pressure fixable developing toner powder of the invention, while the copy in Figure 4 was prepared using a standard pressure fixable developing powder. Both copies were made by a conventional pressure fixing copying process.
Detailed Description of the Invention Referring specifically to Figures 1 and 2, there are shown portions of electrostatic copies prepared using heat fusible developing powders and conventional copying processes. These Figures contain unmagnified typed areas 10 and 20; corresponding magnified typed areas lOA and 20A; unmagniEied preprinted areas 11 and 21; and corresponding magnified preprinted areas llA and 21A.
As can be seen by reference ko areas lOA and llA
o~ Figure 1, typed characters 12A and preprinted characters l3A do exhibit excellent resolution. They have well de~ined edges 14A and virtually no image fill-in, see 15A. Additionally, the copies exhibit virtually no back-grounding, see 16A.
1 1 60~97 The signiEicant improvement in copy quality is shown by comparison of Figures 1 and 2. Thus, neither typed characters 22A nor preprinted characters 23A exhibit good resolution. To the contrary, the characters have fuzzy edges 24A and a signiEicant level of image-fill in, see 25A. Furthermore, the copies exhibit a high degree of backgrounding, see 26A.
A comparison of Figures 3 and 4 further demon-strates the significant improvement in copy quality achieved by the developing powders of the present inven-tion. These Fiyures contain magnified areas 30A and 40A.
The characters 31A in Figure 3 have sharper edges 32A, substantially less image fill-in as shown at 33A than do characters 41A in Figure 4. Compare, for example edges 42A and areas 43A of Figure 4. Moreover, characters 31A are more uniformly toned than are characters 41A. See especially the a, c, d, and e.
Still further, the copy illustrated in Figure 3 demonstrates substantially less backgrounding than does ~o the co~y illustrated in Figure 4. Compare especially areas 34A of Figure 3 with areas 44A of Figure 4.
These surprising results are achieved as a result oE the use of fluorinated carbon in the developin~
powder composition of the invention. The fluorinated carbon useful in the invention comprises an in~rganic compo~nd made up oE carbon chemically bonded to 1uorine by covalent bonds. The fluorinated carbon may comprise ~luorinated graphite (natural or artificial) or, alternatively, fluorinated petroleum coke, coal coke, charcoal, carbon black, and mixtures thereof. Such A materials are known as shown by, for example, "Cermatic", 4(301) 1969; Denki Kagaku, 51, 756-761, 1963; Denki Kagaku, 35, 19-23, 1967.
Processes for the preparation of fluorinated carbon are known. For example, see "Cermatic", supra, and other references. Other process for the preparation of fluorinated carbon involve the direct fluorination of T,O,~Je ~,~
~ 3 6~9~
carbon at temperatures varying Erom ambien~ to over 450C.
Fluorination is preferably carried out in an agitated reactor in an atmosphere of fluorine plus an inert gas, although a non-agitated reactor may be employed if desired.
The conditions utilized during fluorination in a agitated reactor may be varied so as to obtain the desired degree of fluorination. Examples of such conditions, and the degree of fluorination obtained, are set forth in hO Table 1. The carbon used to obtain the data for this Table was Vulca ~ XC 72R, a conductive carhon black with a maximum particle size of 30 millimicron sold by Cahot Corporation.
FL~ORINATION CARBON BhK RXN TIME RXN TEMP FLUORINE
(%) (~) _(hrs)(C) (cc/min) 5.5 7.0 2.2Amhient ~0-52 15.~ l6.5 ~ 0-~10 5-16 20.9 26.3 2200-205 50 24.6 22.7 7150-195 50 31.6 17.6 6.7185-20~ 11 Other carbon materials may also be used in the present i~vention. Representative of such materials are Conductex~950 (maximum particle si~e o~ 21 millimicron) sold by Cities Service, Raven 1800 (Inaximum particle size of 18 millimicron) sold by Columbia Chemicals, Ketjenblack EC sold by Noury, and Thermax MT sold by R. T~ Vanderbilt.
The thermoplastic binder useul in the present invention has a static conductivity as set forth above and i~ selected from waxes that have a melting point in the range of 45C to 150C and organic resins that have a ring and ball softening point above about 60C. Waxes useEul in the invention are normally selected from the group consisting of aliphatic compounds such as waxes ~natural or synthetic), fatty acids, metal salts o Eatty acids, Je ~L~
11 1 6~9~
hydroxylated fatty acids or amides, low molecular weight ethylene homopolymers, or a mixture of -two or more of these materials. Aromatic and polymeric wax-like materials can also be used. All of these materials are well known in the art.
Representative useful aliphatic waxes include paraffin wax, microcrystalline wax, caranauba wax, montan wax, ouricury wax, ceresin wax, candellila wax, and sugar cane wax.
Representative useful ~atty acids include stearic acid, palmitic acid, and behenic acid.
Representative useful metal salts of fatty acids include aluminum stearate, lead stearate, barium stearate, magnesium stearate, zinc stearate, lithium stearate, and zinc palmitate. Representative amide hydroxy waxes include N(betahydroxyethyl)-ricinoleamide ~commercially available under the trade name "Flexricin 115"), N,N'ethylene-bis-ricinoleamide (commercially available under the trade name "Flexricin 185"), N(2-hydroxyethyl)-12-hydroxystearamide (commercially available under the trade name "Paracin 2~0"), and N r N'-ethylene-bis-12-hydroxystearamide (commercially available under the trade name 'IParacin 285").
Representative fatty acid derivatives include castor wax (glyceryl tris-12-hydroxy stearate) r methyl hydroxy stearate tcommercially available under the trade nalne "Paracin 1"), ethylene glycol monohydroxy stearate (commercially available under the trade name "Paracin lS") and hydroxy stearic acid.
Representative ethylene homopolymers include the low molecular weight polyethylenes such as the Bareco Polywaxes such as Polywax 655, 1000, and 2000 sold by the Bareco Division of Petrolite Corporation. Other ethylene homopolymers include oxidized, high density, low molecular weight polyethylenes such as Polywax E-2018 and E-2020 sold by Bareco Division of Petrolite Corporation; and the Epolene~ series of low molecular weight polyethylene t ~ 6~97 g resins such as Epolene~ E-14 available from Eastman Chemical Products Incorporated.
Representative useful aromatic wax-like materials include dicyclohexylphthalate, diphenylphthalate and the Be Square series of waxes from the Bareco Division of Petrolite Corporation, such as Be Square 195~ The Be Square waxes are high melting point waxes that consist of paraffines and naphthenic hydrocarbons.
Representative of organic resins useful as the thermoplastic binder are the polyamides (e.g., "Versamid 950", commercially available from General Mills);
polystyrenes (e.g., 2000 mol. wt.); bisphenol A epoxy resins (e.g., "Epon~1004", commercially available fro~
Shell Chemical Corp); acrylic resins ~e.g., "Elvacite 2044", and N-bu~yl methacrylate commercially available from DuPont); vinyl resins such as polyvinyl butyral (e.g., "Butvar~B72-A," commercially available from Monsanto Company), polyvinyl acetates (e.g., "Gelva V-100", commercially available from Monsanto Company);
vin~l copolym~rs such as vinyl chloride/vinyl acetate (e.g., "VYHH", commercially available from Union Carbide Corp.), ethylene/vinyl acetate copolymers; cellulose este~s such as cellulose acetate butyrate (e.g., "EAB-171-25", commercially available from Eastman Chemical Products~ Inc.), cellulose acetate propionate (e.g., "CAPPLES~70", commercially available from Celanese Corp.);
and cellulose ethers.
When a heat fusible developing powder is L~r~ar~cl the thermoplastic binder preEerably cornprises the organic resin. Most preferably the organic resin has a softening point between about 120C and 200C and comprises a bisphenol A epoxy resin.
When a pressure fixable developing powder is prepared, the thermoplastic binder may comprise either the wax or a combination o the wax and the organic resin.
Preferably the weight ratio of organic resin to wax is in the range of about 0:1 to 1:1. Most preferably ratio is ~ 1 6(~9~
about 0:1. In either event, the wax preferably is selected Erom a microcrystalline wax, a low molecular weight polyethylene resin, or a combination of both, while the organic resin, when present/ comprises a bisphenol A
epoxy resin.
The magnetically responsive material employed in the developing powder composition preferably is homo--geneously distributed throughout the binder.
Additionally, it preferably has an average major dimension of one micron or less. Representative examples o~ useful ma~netically responsive materials include magnetite, barium ferrite, nickel zinc ferrite, chromium oxide, nickel oxide, etc.
Various other materials may also be usefully incorporated in or on the developer composition particles of the present invention. Such materials include, for example, colorants such as powdered flow agents, piyments and, dyes, plasticizers, etc.
Representative po ~ered flow agen-ts inclue small size SiO2 such as "Cab-~ Sil" sold by the Cabot Corporation and "Aerosil" R-972 sold by the DeGussa Corporation.
Representative colorants are carbon blacks, particularly conductive carbon blacks. These may be used in conjunction with the fluorinated carbon employed in the invention.
'l'he developing powders of the invention may be prepared by known processing techniques. Thus, for example, heat fusing developing powders may be prepared by the techniques described in U.S. Patent 3,639,245 at column 5, lines 3 to 36. Pressure fixable developing powders may be prepared by the techniques described in U.S. Patent 3,925,219 at column 4, lines 25-59.
Preferably the powder particles are spherical.
In these processes, the fluorinated carbon is incorporated into the developing powder in the same fashion as is the conductive particles referred to therein. The resultant powder possesses a radially dispersed layer or zone o electrically conductive carbon.
The present invention is further illustrated by means of the following examples wherein the term "parts"
refers to parts by weight unless otherwise indicated.
Heat-fusible developing powders were prepared using the ingredients and amounts shown:
INGREDIENTS PARTS
la lb "EPON" 1004 (Epichlorohydrin/
Bisphenol A solid epoxy resin, melting point 95-105C, epoxy equivalent weight 875-1,025, molecular weight o~ 1400 a trademarked product oE Shell Chemical Company) 40 4Q
MAGNETITE (Cities Service Corporation) 60 60 FLUORINATED CARBON ( 29.6% fluorinated 1.3 ~-Vulcan XC-72R from the Cabot Corporation) ~0 NON-FLUORINAT~D CARBON (VULCAN XC-72R) -- 0.53 The "Epon" and the Magnetite were blended thoroughly on a conventional heated-roll rubber mill. The resulting blend was pulverized in an attrition-t~pe grinder and then classified in a standard air centrifugal type machine. These particles were sharp edged and pseudocubical in shape. They were spheroidized such that most of the particles were transformed into sphere like shapes or round-edged particles by the Eollowing process.
'l'he mixture was fed to an air aspirator in a uniform stream o~ about 800 grams per hour. The aspirator sucked the particles into the air stream and dispersed them ~orming an aerosol. The aerosol was directed at 90 into a heated air stream the temperature of which was about 510-540C. The powder was then allowed to settle and was collected by filtration.
The spheroidized particles were combined with either the fluorinated or the non-Eluorinated carbon and then blended first at room temperature for 3 hours and then at 65C for about 8 hours~ The carbon was then radially dispersed or embedded into the resin by the spheroidization process described above except that the temperature of the hot air stream was adjusted to 650C
and the powder was fed to the air stream at a rate of about 36 ]cilograms per hour. The resultant developing powder compositions were collected and classifled so that 95% by weight o the product was greater than 6.5 microns average diameter and only 5% by weight was greater than 19 microns average diameter.
The final step in the process was to blend 0.05 parts per hundred parts of developing powder composition of a small size SiO2 flow ayent (i.e., Aerosil R-972 sold by the DeGussa Corporation with the composition. The resultant compositions were tested for static conductivity. The results are given in Table 2.
Example Carbon Static Conductivity (Mhos/cm) _ 1000 v/cm -15 la Fluorinated 2.3 x 10 lb non-fluorinaged 2.7 x 10 15 This data demonstrates that the use of fluorinated carbon enables a larger quantity of conductive material to be employed in the developing powder composi-tions in order to achieve a given static conductivity.
This in turn provide~ improved flow characteristics even under conditions of high humidity.
116~)~97 Each of the developing powder compositions was used in a conventional heat-fusing copying process to provide images on a plain paper substrate. The developiny powder composition of Example la provided copies with images that were sharply defined and had virtually no image fill-in. Additionally there was virtually no hackgrounding. A photomicrograph of a copy prepared from the powder of Example la, is shown in Figure 1. The developing powder composition of Example lb provided copies with images that were not sharply defined and had substantial amounts of image fill-in. Furthermore, there was a ~ignificant degree of backgrounding~ A photomicro-graph of a copy prepared from the powder of Example lb is shown in Figure 2.
A heat-fusible developing powder composition was prepared as described in Example 1 except that embedment was carried out at 430C. The following ingredients and amounts shown were used.
"EPON" 1004 40 FLUORINATED CARBON
(63~ Fluorinated Graphite sold by Air Products and Chemicals, Inc.) 0.57 NON-FLUORINATE~ CARBON (Vulcan XC-72R) 0.57 The resultant developiny powder composition was classiEied so that 95% by weight of the powder was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivity of the developing powder was 2.8 x 10 15 mhos/cm in a 10,000 volt/cm d.c. field~ The developing powder was used in a heat-fusing copying process to provide a copy with well defined images and virtually no 9 ~
image fill-in or backgrounding on a plain paper substrate.
Example 1 was repeated except that embedment was carried out at about 430C. In Example 3a, 0.49 parts by weight of fluorinated Vulcan XC-72R (8.4% fluorination) was employed, while in Example 3b, 0.42 parts by weight of non-fluorinated Vulcan XC-72R was used. The static conductivity of the resultant developing powder composi-tions is reported in Table 3.
Example Carbon Black Static Conductivity (mhos/cm) _ _ 000 v/cm 15 3a fluorinated 5.5 x 10 15 3b non-fluorinated 9.0 x 10 1 When each of these compositions was employed in a heat fixing copying process to produce images on a plain paper substrate, no difEerence could be seen between ~he quality of the copies produced. Thus, in each case the images had poor edge definition and a fair degree of image fill in. Consequently, this example demonstrates that the fluorinated carbon must have a degree of fluorination of at least 10~.
EXAMP~E ~
Pressure-fixable developing powders were prepared using the following ingredients in the amounts stated:
1 .~ 6~g7 PARTS
INGREDIEN~S 4a 4b ~OLYW~X E2018 (Oxidi~ed hi~h density, 10 10 molecular weight polyethylene sold by Bareco Division of Petrolite Corporation) BE SQUARE 195 (Hard microcrystalline was 30 30 sold by sareco Division of Petrolite Corporation) 10 FLUORINATED CARBON (29.4% fluorinated 108 Conductex 950 from Columbia Carbon) ~ION-F1UORINATED CARBON (Conductex 950) -- 1.8 The Polywax and the Be Square were first heated to melting after which the magnetite was added, with stirring, and heated until a homogeneous dispersion was obtained. The temperature of the dispersion was raised to l93C and then sprayed through a nozzle at a rate of about 91 kg/hr to form discrete particles. The particles were classified so that 95% by weight were greater than 6.5 microns and no more than 5% by weight were greater than 20 microns in average diameter.
The substantially spherical particles were then combined with the fluorinated or non-fluorinated carbon black and blended for 3 hours at room temperature. The particles were then spheroidized and the carbon embedded therein as described in Example 1. Embedment was carried out at about 430C.
The developing powder compositions were then classified so that 95% by weight of the powder was greater than 6.5 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivities of these developing powder compositions were measured and are reported in Table 4.
Example Carbon Black Static Conductivity (Mhos/cm) _ 10,000 v/cm 4a Fluorinated 2 x lO
4b Non-fluorinated >lO 4 Ea~h of the developing powder compositions was used in a pressure~fixing copying process to provide i~ages on a plain paper substrate. The developing powder composition of Example 4a provided copies whose images were sharply defined and had virtually no image fill-in.
Moreover, the copies had virtually no backgrounding. A
photomicrograph of a copy prepared using the developing 15 powder of Example 4a is shown in Figure 3. The developing powder composition of Example 4b, on the other hand, provided copies whose images had poor edge definition and a high degree oE image fill-in. Additionally, the background areas of the copies produced ~rom the 20 developing powder composition of Example 4b had a high degree of backgrounding. A photomicrograph of a copy prepared using the developing powders of Example 4b is shown in Figure 4.
~XAMPLE 5 Example 4 was repeated except that Vulcan XC-72R
(l.6 parts by weight) that had a degree o~ ~luorination oE
20.~% was utilized in Example 5a and 0.62 parts by weight of non-fluorinated Vulcan XC-72R was used in Example 5b.
The developing powder compositions were classified so that 95~ by weight o~ the powder was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average diameter. The static conductivity of the resultant developing powder compositions is reported in Table 5.
~ 1 6~9~
Example Carbon Black Dynamic Conductivity (Mhos/cm~
10,000 v/cm _ _ _ _ 5a Fluorinated 2 x 10 5b non-fluorinated 3 x 10 10 Each of the developing powder compositions was used in a pressure-fixing copying process to provide images on a plain pap~r ~ubstrate. The developing powder composition o~ Example 5a provided copie~ whose images were sharply defined and had virtually no image fill-in.
The copies exhibited little backgrounding. The developing powder composition of Example 5b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies exhibited substantial backgrounding.
Example 4 was repeated using the following ingredients in the amounts shown:
INGREDIENTS PARrrS
6a 6b 13E SQ~ E 195 30 30 FLUORINATE~ CARBON ( Vulcan XC-72R, 13.8% fluorination) 1.24 --NON-FLUORINATED CARBON ( Vulcan XC-72R) -- 0.62 The developing powder compositions were classi-fied so that 95~ by weight of the powder was greater than 8 microns average diameter and only 5~ by weight was greater than 20 microns average diameter. The st~tic conductivity of the resultant developing powder composi-tions i5 reported in Table 6.
~16~97 TABL~ 6 Example Carbon Black Static Conductivity (Mhos/cm) 5 ___ 10,000 v/cm 6a Fluorinated 8 x 10 ll 6b non-fluorinated 3 x 10 10 Each of the developing powder compositions was used in a pressure fixing copying process to provide images on a plain paper substrate. The developing powder composition of Example 6a provided copies whose images were sharply defined and had virtually no image fill-in.
The copies exhibited lit~le backgrounding. The developing powder composition of Example 6b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies also exhibited substantial backgrounding.
Example 4 was repeated using the following ;~n ingredients in the amounts shown:
I NGREDI ENT . P RTS
7a 7b POLYWAX 1000 (A low molecular weight, unmodified homopolymer o ethylene having 25 a MW/Mm of 1.2 sold by Bareco Division of Petrolite Corp.) 42 42 FLUORINATED CARBON (25.6% fluorinated Vulcan XC-72R~ 1.54 --NON-FLUORINATED CARBON (Vulcan XC-72R) -- 0.62 The resultant developing powder compositions were collected and classified so that 95~ by weight of the products was greater than 8 microns average diameter and only 5% by weight was greater than 20 microns average 1 1 B~9~
diameter. The dynamic conductivities of the resultant compositions are reported in Table 7.
Example Carbon Dynamic Conductivity (mhos/cm~
__ _ _ 10,000 v/cm 7a Fluorinated l.9 x lO lS
7b Non-Fluorinated 1.5 x lO 15 Each of the developing powder compositions was used in a heat-fusing copy process to provide images on a plain paper substrate. The developing powder compositi on of Example 7a provided copies whose images were sharply de~ined and had virtually no image fill-in. The copies exhibited very little backgrounding. The developing powder composition of Example 7b provided copies whose images were not sharply defined and had substantial amounts of image fill-in. The copies also exhibited substantial backgrounding.
A pressure-fixable developin~ powder was prepared as described in Example 4 using the following in~redient.s in the amounts shown:
I REDIENTS PARTS_ _ EPOLENE~ E-14 ( emulsifiable low molecular weight polyethylene resin available from Eastman Chemical Products, Incorporated) 30 30 FLUORLNATED CARBON (25.6% fluorinated Vulcan XC-72R) 1.05 1 1 60~97 The resul~ing developiny powder composition was collected and classified so that 95% by weight of the product was greater than 9 minus average diameter and only 5% by weight was greater than 22 microns averaye diameter.
The composition had a dynamic conductivity of 5.3 x 10 13 Mhos/cm in a 10,000 volt/cm electric fold. The composition was used in a heat Eusing copy process one claim per substrate and provided copies whose images were sharply defined and exhibited virtually no image fill-in, Furthermore, the copies exhibited very little backgrounding.
Claims (10)
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A flowable, dry powder of particles that has a static conductivity of less than about 10 3 mhos per centimeter in an electric field of 10,000 d.c. volts per centimeter comprising a) from about 30 to 80 parts by weight of a thermoplastic binder that has a static conductivity of at most about 10-12 mhos per centimeter, said binder being selected from the group consisting of waxes that have a melting point in the range of about 45°C to 150°C, organic resins that have a softening point above about 60°C, and mixtures of said waxes and said resins; and correspondingly, from about 70 to 20 parts by weight of a magnetically responsive material and (b) from about 0.4 to 3 parts by weight per 100 parts by weight of (a) of fluorinated carbon that has a degree of fluorination in the range of 10% to 63% and an average diameter below about 2 microns; wherein said fluorinated carbon comprises a radially dispersed zone around the outer portions of said powder particles.
2. A powder in accordance with claim 1 that has a static conductivity less than about 10 10 mhos per centimeter in in electric field of 10,000 d.c. volts per centimeter.
3. A powder in accordance with claim 1 wherein at least about 95 number percent of said particles have a maximum dimension in the range of about 4 to 30 microns.
4. A powder in accordance with claim 1 wherein said particles are essentially spherical.
5. A powder in accordance with claim 1 wherein said fluorinated carbon has an average diameter of below about 100 millimicrons.
6. A powder in accordance with claim 1 wherein said fluorinated carbon comprises from about 0.75 to 3 parts by weight per 100 parts by weight of (a) and wherein said fluorinated carbon has a degree of fluorination in the range of 15% to 30%.
7. A powder in accordance with claim 6 wherein (a) comprises from about 35 to 45 parts by weight of said thermoplastic binder, and, correspondingly, from about 65 to 55 parts by weight of said magnetically responsive material.
8. A powder in accordance with claim 1 wherein the weight ratio of said organic resin to said wax in said binder is in the range of about 0:1 to 1:1, and wherein said powder is pressure-fixable.
9. A powder in accordance with claim 1 wherein said binder comprises said organic resin and wherein said powder is heat fusible.
10. A powder in accordance with claim 1 wherein said fluorinated carbon comprises fluorinated carbon black.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15993980A | 1980-06-16 | 1980-06-16 | |
| US159,939 | 1980-06-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1160497A true CA1160497A (en) | 1984-01-17 |
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ID=22574759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000378122A Expired CA1160497A (en) | 1980-06-16 | 1981-05-22 | Fluorinated carbon-containing developer composition |
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| Country | Link |
|---|---|
| EP (1) | EP0042224B1 (en) |
| JP (1) | JPS5735869A (en) |
| CA (1) | CA1160497A (en) |
| DE (1) | DE3162946D1 (en) |
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|---|---|---|---|---|
| JPS59101454A (en) * | 1982-12-02 | 1984-06-12 | Chisso Corp | Process for cooling and crystallization of molten guanidine sulfamate |
| US4524119A (en) * | 1983-07-25 | 1985-06-18 | Allied Corporation | Electrophotographic carriers incorporating fluorinated carbon and process of using same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL159795C (en) * | 1968-07-22 | Minnesota Mining & Mfg | ||
| US4141849A (en) * | 1977-02-22 | 1979-02-27 | Canon Kabushiki Kaisha | Developer for developing electrostatic latent images |
| JPS53124428A (en) * | 1977-04-07 | 1978-10-30 | Mita Industrial Co Ltd | Developing agent for use in electrostatic image |
| JPH10153676A (en) * | 1996-11-20 | 1998-06-09 | Toshiba Corp | Controller for reactor control rod drive mechanism |
-
1981
- 1981-05-22 CA CA000378122A patent/CA1160497A/en not_active Expired
- 1981-05-27 DE DE8181302338T patent/DE3162946D1/en not_active Expired
- 1981-05-27 EP EP19810302338 patent/EP0042224B1/en not_active Expired
- 1981-06-16 JP JP9292281A patent/JPS5735869A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0042224A1 (en) | 1981-12-23 |
| DE3162946D1 (en) | 1984-05-10 |
| JPS5735869A (en) | 1982-02-26 |
| EP0042224B1 (en) | 1984-04-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |