Inks and liquid developers containing colored silica particles

A liquid developer composition which comprises a liquid medium, a polymeric material soluble in the liquid medium, a charge control agent, and a plurality of colored particles consisting, essentially of hydrophilic silica particles, to the surfaces of which dyes are covalently bonded through silane coupling agents, wherein the dye includes a reactive group selected from the group consisting of dichlorotriazines, monochlorotriazines, dichloroquinoxalines, aminoepoxides, mono-(m'-carboxypyridinium)-triazines, 2,4,5-trihalogenopyrimidines, 2,4-dichloropyrimidines, 2,3-dichloroquinoxalines, monofluorotriazines, 4,5-dichloro-6-methyl-2-methylsulfonylpyrimidines, 1,4-dichlorophthalazines, chlorobenzo-thiazoles, -sulfatoethylsulfones, .beta.-chloroethylsulfones, 4,5-dichloro-6-pyridazones, .alpha.-bromoacryloylamidos, and .alpha.,.beta.- dibromopropionylamidos.

A liquid developer composition which comprises a liquid medium, a polymeric material soluble in the liquid medium, a charge control agent, and a plurality of colored particles consisting essentially of hydrophilic silica particles, to the surface of which dyes are covalently bonded through silane coupling agents, wherein the particles are prepared by a process which comprises reacting hydrophilic silica particles with a silane coupling agent in the absence of water to form particles having covalently attached thereto coupling agents, followed by reacting a dye with the coupling agent, wherein the dyes are selected from the group consisting of anthraquinones, phthalocyanines, azaannulenes, formazan copper complexes, and triphenodioxazines, to which are covalently attached reactive groups.

A process for preparing a liquid developer which comprises reacting hydrophilic silica particles with a silane coupling agent in the absence of water to form silica particles having covalently attached thereto coupling agents, subsequently reacting a dye with the coupling agent to form colored silica particles to the surface of which the dye is covalently bonded through the silane coupling agent, recovering and drying the colored silica particles, admixing the colored silica particles with a liquid medium and a polymeric material soluble in the liquid medium, and adding to the mixture a charge control agent, wherein the dyes are selected from the group consisting of anthraquinones, phthalocyanines, azaannulenes, formazan copper complexes, and triphenodioxazines, to which are covalently attached reactive groups.

A liquid developer composition which comprises a liquid medium, a charge control agent, and a plurality of colored particles comprising a resin insoluble in the liquid medium and hydrophilic silica particles, to the surface of which dyes are covalently bonded through silane coupling agents, wherein the silica particles are prepared by a process which comprises reacting hydrophilic silica particles with a silane coupling agent in the absence of water to form particles having covalently attached thereto coupling agents, followed by reacting a dye with the coupling agent, and wherein the dyes are selected from the group consisting of anthraquinones, phthalocyanines, azaannulenes, formazan copper complexes, and triphenodioxazines, to which are covalently attached reactive groups.

A process for preparing a liquid developer which comprises reacting hydrophilic silica particles with a silane coupling agent in the absence of water to form silica particles having covalently attached thereto coupling agents, subsequently reacting a dye with the coupling agent to form colored silica particles to the surface of which the dye is covalently bonded through the silane coupling agent, recovering and drying the colored silica particles, admixing a liquid medium and a resin insoluble in the liquid medium, admixing the colored silica particles with the liquid medium and resin, and adding to the mixture a charge control agent, wherein the dyes are selected from the group consisting of anthraquinones, phthalocyanines, azaannulenes, formazan copper complexes, and triphenodioxazines, to which are covalently attached reactive groups.

A liquid developer composition which comprises a liquid medium, a charge control agent, and a plurality of toner particles comprising a resin and colored hydrophilic silica particles, to the surfaces of which silica particles dyes are covalently bonded through silane coupling agents, wherein the dyes are selected from the group consisting of anthraquinones, phthalocyanines, azaannulenes, formazan copper complexes, and triphenodioxazines, to which are covalently attached reactive groups.