Classifications

• • 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
  • G03G9/087—Binders for toner particles
  • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • 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
  • G03G9/097—Plasticisers; Charge controlling agents
  • G03G9/09733—Organic compounds

Definitions

• This invention relates to a toner for developing electrostatic image in electrophotography, electrostatic recording, electrostatic printing and the like.
• This invention is directed to a dry toner for development of electrostatic image to be employed for the dry development method.
• the method for fixing a dry toner is a method wherein the toner image formed by development is directly fused and fixed onto a photoconductive photosensitive material or an electrostatic recording material having the electrostatic image or another method wherein the toner image formed by development is transferred onto a transfer sheet such as paper from the photoconductive photosensitive material or electrostatic recording material having the said image and subsequently fused onto the transfer sheet.
• fusion of toner image can be conducted either by contacting with a solvent vapor of the resin for toner or by direct or indirect heating to the toner image, wherein heating is effected by a non-contact heating manner with an electric furnace such as nichrom heater or ceramic heater or by a contact heating manner with heating roller.
• the said fixing method using heating roller is effected by passing the powder toner particle image surface of the sheet to be fixed in contact with under pressure the surface of heating roller with a built-in heating source such as nichrom heater or ceramic heater, said surface being made of a non-tacky or releasing material, to fix the said image onto the said sheet with heat fusion.
• a built-in heating source such as nichrom heater or ceramic heater, said surface being made of a non-tacky or releasing material
• This method is regarded as being effective with regard to inhibition of offset in toner, but has disadvantages that the offset inhibiting liquid when heated tends to produce odor, that a complicated mechanism in a copying device is required owing to the need of additional device to feed the offset inhibiting liquid to the fixing roller surface and that a copying device itself is expensive because of the required high precision for good stability results.
• Japanese Patent Laid-Open Application No. 133242/1975 or Japanese Patent Published Application No. 6895/1980 discloses a toner for developing electrostatic image which contains as a main component for dry toner resin component the so-called two stage polymerization resin formed by polymerization of a mixture of a polymeric monomer with a highly polymerized resin and having a high dispersion degree, i.e., weight average molecular weight(Mw)/number average molecular weight(Mn).
• the said two stage polymerization resin has disadvantage in its preparation that increased number of steps is required for its preparation and the viscosity of a solution of a highly polymerized resin homogeneously dissolved in a monomer is increased, which leads to poor workability and difficult polymerization control. Moreover, the unreacted monomer tends to readily remain in the resulting resin at the end of polymerization. Also, when a dry toner is derived from the said resin, there is disadvantage in the use of the toner that there may easily occur blocking property, the characteristic of the toner, and stain on the lower roller attached to the fixing roller on long run.
• the toner for developing electrostatic image containing as a main component a crosslinked resin As disclosed in Japanese Patent Published Application No. 23354/1976, there has been proposed the toner for developing electrostatic image containing as a main component a crosslinked resin. According to this method, offset property can be given to a toner, a fixing device is simplified and workability problem in preparation, blocking property and stain in the lower roller on long run can be improved. However, the toner for developing electrostatic image containing as a main component a crosslinked resin shows disadvantage of being a higher softening point and a reduced fixing property.
• the present inventors have made earnest studies and, as a result, found out a new toner for developing electrostatic image which can eliminate the aforesaid disadvantages.
• a primary object of this invention to provide a new dry toner for developing electrostatic image which can be used for fixation with heating roller without production of offset phenomenon of the toner even when a fixing roller without any supply of an offset inhibiting liquid onto the surface of said fixing roller is employed.
• Another object of this invention is to provide a dry toner for developing electrostatic image having a good fixing property.
• a further object of this invention is to provide a dry toner for developing electrostatic image which has a fluidity and a storage stability without any blocking.
• a still further object of this invention is to provide a dry toner for development of electrostatic image without any stain in the lower roller attached to a fixing roller even on long run operation.
• the present invention is directed to a toner for development of electrostatic image.
• the present toner comprises a polymer obtained by polymerization of a vinyl monomer in the presence of two or more polymerization initiators having different half-life periods.
• the present toner may comprise as a main component the said vinyl polymer and at least one of releasing substances selected from a polyolefin, a polysiloxane, a fatty acid metal salt, a higher fatty acid, a higher alcohol, a higher fatty acid amide, a natural paraffin and a synthetic paraffin.
• the present toner may comprise a polymer obtained by polymerization of a vinyl polymer in the presence of two or more polymerization initiators having different half-life periods and a crosslinking agent.
• the present toner may comprise as a main component the latter polymer and at least one of the above-defined releasing substances.
• the vinyl resin for toner is applied as a main component for a dry toner, whose resin can be prepared by one stage polymerization of a vinyl monomer in the presence of a polymerization initiator from the initial stage of polymerization, said initiator having a ratio of the half-life period ( TA ) of a longer half-life polymerization initiator A to the one ( ⁇ B ) of a shorter half-life polymerization initiator B at 70°C in the range of 10 to 10 6 .
• a rapid initiation system is prepared for the initiator having a shorter half-life period, which a slow initiation system is prepared for the initiator having a longer half-life period.
• a concentration of the active species [P] may be represented according to the following equation:
• thermal decomposition of a polymerization initiator is saturated at the initial stage, a polymerization rate decreases as a polymerization time goes and all active species are deactivated prior to exhaustion of all monomers for reaction. Then, a saturated state of a polymerization yield is observed at an early stage and a polymerization degree of the resultant resin is also lowered.
• a concentration of the active species [P] in the slow initiation system may be represented according to the following equation: wherein, IoRIdt: Concentration of resultant initiation species
• a ratio of the half-life period of a polymerization initiator A having the longest half-life period to the one of a polymerization initiator B having the shortest half-life period at 70°C is preferably 10 to 10 6 .
• the ratio is less than 10
• Mw/Mn dispersion degree
• the half-life period of the slow initiation type initiator in this invention is preferably 3 to 30 hours. When it is shorter than 3 hours, there can not be produced a toner resin having a good offset property, while it may disadvantageously take a too long time to complete polymerization when it is longer than 30 hours.
• a polymerization temperature which may be usually applied in this invention is 40 to 100°C, preferably 60 to 90°C.
• the polymerization temperature may be varied during polymerization process provided that a ratio of the half-life period ( TA ) of the longest half-life polymerization initiator A to the one ( TB ) of the shortest half-life polymerization initiator B ( ⁇ A / ⁇ B ) at 70°C should be in the range of 10 to 10 6 . Since control for molecular weight distribution of the resulting vinyl resin may also depend upon the sort and added amount of the polymerization initiator, said control should be effected from a general point of view inculd- ing these factors.
• polymerization initiators which may be employed in this invention, there may be employed any of oil- soluble initiators commonly used in the art.
• oil- soluble initiators commonly used in the art.
• Representative examples thereof may include a peroxide initiator such as acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, 2,4-dichlorobenzyl peroxide, t-butyl peroxypivalate, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, decanonyl peroxide, lauroyl peroxide, stearoyl peroxide, propionyl peroxide, succinic acid peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide
• the rapid-initiation initiator there may be preferably employed 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile and the like, while benzoyl peroxide and the like may be mentioned as the slow-initiation initiator.
• crosslinking agent which may be employed in this invention, there may be mainly employed a compound having two or more polymerizable double bonds; for example, an aromatic divinyl compound such a diethylenic carboxylic acid ester as ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, allylmethacrylate, tetraethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate and the like; other divinyl compound such as N,N-divinylaniline, dinivyl ether, divinyl sulfide, divinyl sulfone and the like; and a compound having 3 or more vinyl groups and these agents may be employed alone or in combination therewith.
• an aromatic divinyl compound such a diethylenic carboxylic acid ester as ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, allylmethacrylate
• the crosslinking agent may be added in a range of 0.001 to 5%, upon the total weight of the monomer employed, and preferably 0.001 to 0.5%, as a too large amount thereof tends to increase a softening point to deteriorate its fixing ability.
• vinyl resin as used herein is meant to include a monopolymer of a vinyl monomer and a copolymer resin of a vinyl monomer with other copolymerizable monomer.
• a styrene for instance, styrene, a-methylstyrene, p-methylstyrene, p-tert-butylstyrene, p-methoxystyrene, p-phenylstyrene, 3,4-dichlorostyrene, an a-methyl unsaturated monocarboxylic acid ester for instance, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl a-chloroacrylate, methyl methacrylate, ethyl methacrylate
• an ethylenic unsaturated monoolefin such as ethylene, propylene, butylene, isobutylene and the like
• a vinyl halide such as vinyl chloride, vinyl bromide, vinyl fluoride, a vinyl ester such as vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, vinyl benzoate, vinyl formate, vinyl caproate and the like
• a vinyl ether such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like
• a vinyl ketone such as vinyl methyl ketone, vinyl hexyl ketone and the like; and the like.
• any suitable pigments or dyes as a coloring agent.
• carbon black including pre-polymerized or grafted carbon black
• Nigrosine dyes C.I. No. 50415B
• Aniline Blue C.I. No. 50405
• Chalcoil Blue C.I. No. Azoec Blue 3
• Chrome Yellow C.I. No. 14090
• Ultramarine Blue (C.I. No. 77103)
• Du Pont Oil Red C.I. No. 26105
• Quinoline Yellow C.I. No. 470051
• Methylene Blue Chloride C.I. No. 52015
• Phthalocyanine Blue C.I. No.
• the offset inhibition agent which may be employed in this invention can be selected from releasing substances having a lower fusing point than a softening point of the binder forming a toner and a low surface energy.
• the offset inhibition agent suitable for the present toner there may be mentioned, for example, a polyolefin, a fatty acid metal salt, a fatty acid ester, a partially saponified fatty acid ester, a higher fatty acid, a higher alcohol, a liquid or solid paraffin wax, an amide-type wax, a polyhydric alcohol ester, a silicone vanish or polysiloxane, an aliphatic fluorocarbon and the like. Also, there may be employed these agents alone or in admixture with two or more.
• polystyrene resin As the said polyolefin, there may be mentioned those - polyolefins having a softening point (measured according to the ring and ball method prescribed in JIS standard 2531 - 1960) of 80 to 180°C, preferably 100 to 160°C, such as polypropylene, polyethylene, polybutene and the like.
• fatty acid metal salt there may be mentioned, for example, maleic acid salts with zinc, magnesium, calcium and the like; stearic acid salts with zinc, cadmium, barium, lead, iron, nickel, cobalt, copper, aluminum, magnesium and the like; dibasic stearic acid lead salt; oleic acid salts with zinc, magnesium, iron, cobalt, copper, lead, calcium and the like; palmitic acid salts with aluminum, calcium and the like; caprylic acid lead salt; caproic acid lead salt; linolic acid salts with zinc, cobalt and the like; ricinolic acid calcium; ricinoleinic acid salts with zinc, cadmium and the like; and a mixture thereof.
• maleic acid salts with zinc, magnesium, calcium and the like stearic acid salts with zinc, cadmium, barium, lead, iron, nickel, cobalt, copper, aluminum, magnesium and the like
• dibasic stearic acid lead salt oleic acid salts
• fatty acid ester there may be mentioned, for example, ethyl maleate, butyl maleate, methyl stearate, butyl stearate, cetyl palmitate, montanic acid ethylene glycol ester and the like.
• partially saponified fatty acid ester there may be mentioned, for example, calcium-partially saponified product of montanic acid ester and the like.
• the said higher fatty acid there may be mentioned, for example, dodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linolic acid, ricinolic acid, arachinic acid, behenic acid, lignoceric acid, selacholeic acid, and the like and a mixture thereof.
• the said higher alcohol there may be mentioned, for example, dodecyl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, arachyl alcohol, behenyl alcohol and the like.
• the said paraffin wax there may be mentioned, for example, natural paraffin, micro wax, synthetic parattin, chlorinated hydrocarbon and the like.
• amide-type wax there may be mentioned, for example, stearic amide, oleic amide, palmitic amide, lauryl amide, behenic amide, methylenebisstearoamide, ethylenebisstearoamide and the like.
• polyhydric alcohol ester there may be mentioned, for example, glycerol stearate, glycerol ricinolate, glycerol monobehenate, sorbitan monostearate, propylene glycol monostearate, sorbitan trioleate and the like.
• silicone varnish or polysiloxane there may be mentioned, for example, methyl silicone varnish, phenyl silicone varnish, dimethylpolysiloxane and the like.
• aliphatic fluorocarbon there may be mentioned, for example, a low polymeric compound such as ethylene tetrafluoride or propylene hexafluoride; a fluorine-containing surface active agent as disclosed in Japanese Patent Laid-Open Application No. 124428/1978 and the like.
• An amount of the offset inhibition agent comprising such releasing substance to be incorporated into the toner is 0.1 to 10% by weight, preferably 1 to 5% by weight. In case of too small amount, offset phenomenon tends to occur, while toner fluidity becomes poor with decreased cleanability in case of too large amount.
• the present toner for developing electrostatic image may include, if necessary, a variety of other toner additives, e.g., an electric charge controlling agent, a plasticizer and the like.
• any useful magnetic coloring agent for the toner of mono- component developer there may be employed in this invention any useful magnetic coloring agent for the toner of mono- component developer.
• the magnetic coloring agent there may be desirably employed any of those substances which can be strongly magnetized along magnetic field and, preferably, has a black color, a good dispersibility in resin with chemical stability and an easy availability of the finely divided particle form with a particle size of less than l ⁇ .
• magnetite tri-iron tetroxide
• magnetic or magnetizable materials may include a metal such as cobalt, iron, nickel; an alloy or mixture of such metal as aluminum, cobalt, steel, lead, magnesium, nickel, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium; a metal compound containing a metal oxide such as aluminum oxide, iron oxide, copper oxide, nickel oxide, zinc oxide, titanium oxide, magnesium oxide; a refractory nitride such as vanadium nitride, chromium nitride; a carbide such as tungsten carbide, silica carbide; ferrite; and a mixture thereof.
• An amount of such a strongly magnetic substance to be incorporated into a toner is desirably of about 30 to 300 parts by weight, particularly preferably, 50 to 200 parts by weight upon 100 parts by weight of resin components.
• Toner Sample 1 100 parts of the present Resin Sample A were admixed with 10 parts of carbon black (Mitsubishi Carbon Black #30, manufacture by Mitsubishi Chemical Industries Ltd.) and 1 part of "Oil Black BW" (a charge controlling agent, tradename of Orient Kagaku K. K.), fused and kneaded with a roll mill and then ground and classified with a jet mill to prepare a toner.
• This toner is designated as Toner Sample 1.
• Toner Sample 2 a styrene-acrylic copolymer resin was prepared and formed into a toner in the same manner as in Example 1. This toner is designated as Toner Sample 2.
• Toner Sample 4 With 67 parts of tri-iron tetroxide powder "Mapicoblack BL-500" (manufactured by Titan Kogyo K. K.) and 0.3 part of methylene blue-chloride (a charge controlling agent) were admixed 100 parts of the Resin Sample A and then fused and kneaded with Banbury mixer and ground and classified with a jet mill to form a uni-component magnetic toner. This toner is designated as Toner Sample 4.
• Comparative Toner Sample 1 In a mixture of 85 parts of styrene and 15 parts of n-butyl acrylate were dissolved 0.5 part of lauroyl peroxide and 0.5 part of octanoyl peroxide to form a polymerization composition. By the same procedures as in Example 1 except that a polymerization temperature was 60°C, a resin was prepared and formed into a toner. This toner is designated as Comparative Toner Sample 1.
• a copolymer resin was prepared according to the double-stage process.
• the toner according to this invention is excellent in offset, fixing and blocking properties as compared with the prior art toner and also shows less stain of under roller in long-run.
• the double-stage process for preparing the resin as shown in the Comparative Example 2 provided a more reduced yield as compared with the present process and also a problem in its workability.
• Toner Sample 6 A mixture of 100 parts of the Resin Sample B, 10 parts of carbon black, 1 part of Oil Black BW and 2 parts of stearic acid was formed into a toner. This toner is designated as Toner Sample 6.
• Toner Sample 7 A mixture of 100 parts of the Resin Sample C, 10 parts of carbon black, 1 part of Oil Black BW and 1 part of sodium oleate was formed into a toner. This toner is designated as Toner Sample 7.
• Toner Sample 8 Following the same procedures as in the above Example 4 except that 3 parts of a low molecular polypropylene (Biscol 550P, manufactured by Sanyo Chemical Industries, Ltd.) were additionally employed, there was prepared a uni-component magnetic toner. This toner is designated as Toner Sample 8.
• a mixture of 100 parts of the Sample D, 10 parts of carbon black, 1 part of Oil Black BW and 3 parts of a low molecular polyolefin was formed into a toner.
• This toner is designated as Comparative Toner Sample 3.
• Toner Sample 4 100 parts of the Resin Sample E, 10 parts of carbon black, 1 part of Oil Black BW1 and 3 parts of a low molecular polyolefin were admixed to form a toner, which is designated as Toner Sample 4.
• Toner Sample 9 a toner was prepared according to the same procedures as in the above Example 1 except that 100 parts of the Resin Sample F were employed. This toner is designated as Toner Sample 9.
• Toner Sample 10 Following the same procedures as in the above Example 2 except that 0.3 part of divinyl benzene was additionally employed, there was prepared a toner, which is designated as Toner Sample 10.
• Toner Sample 11 Following the same procedures as in the above Example 3 except that 0.1 part of trimethylolpropane triacrylate was additionally employed, there was prepared a toner, which is designated as Toner Sample 11.
• Toner Sample 12 a uni-component magnetic toner. This toner is designated as Toner Sample 12.
• Comparative Toner Sample 7 Following the same procedures as in the above Comparative Example 6 except that 0.1 part of ethylene glycol dimethacrylate was employed, there was prepared a toner. This toner is designated as Comparative Toner Sample 7.
• Toner Sample 13 100 parts of the Resin Sample F were employed instead of the Resin Sample A, thereby forming a toner.
• This toner is designated as Toner Sample 13.
• Toner Sample 14 100 parts of the Resin Sample G were employed, thereby forming a toner, which is designated as Toner Sample 14.
• Toner Sample 15 100 parts of the Resin Sample H were employed, thereby forming a toner, which is designated as Toner Sample 15.
• Toner Sample 16 This toner is designated as Toner Sample 16.
• Toner Sample 8 This toner is designated as Toner Sample 8.
• Comparative Toner Sample 9 a toner, which is designated as Comparative Toner Sample 9.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Developing Agents For Electrophotography (AREA)

Applications Claiming Priority (8)

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Cited By (6)

Citations (1)

• 1982
  • 1982-08-02 DE DE8282304081T patent/DE3270107D1/de not_active Expired
  • 1982-08-02 EP EP19820304081 patent/EP0072176B1/de not_active Expired

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