The patent's assignee is National Research Council Of Canada.
News editors obtained the following quote from the background information supplied by the inventors: "The disclosure relates generally to toner additives, and in particular, toner additives that provide desired higher toner charge and low relative humidity (RH) sensitivity. The toner additives comprise titania nanotubes or titania nanosheets in combination with or in place of the commonly used anatase or rutile crystalline titania.
"Toners can comprise at least a binder resin, a colorant and one or more external surface additives. The external surface additives can be added in small amounts. Examples of external surface additives include, for example, silica, titanium dioxide, zinc stearate and the like. The properties of a toner are influenced by the materials and amounts of the materials of the toner. The charging characteristics of a toner also can depend on the carrier used in a developer composition, such as, the carrier coating.
"Toners having triboelectric charge within the range of about -30 .mu.C/g to about -45 .mu.C/g may be achieved by including smaller-sized silica particles as external additives, for example silica particles having average sizes of less than about 20 nm, such as, for example, R805 (.about.12 nm) and/or 8972 (.about.16 nm) (
"Thus, there remain problems with providing high charge with good relative humidity (RH) sensitivity of charge to changing environmental conditions for toner compositions. While many toners contain silica as a surface additive to provide high charge, silica is known to be RH sensitive. Hence, it is a goal to provide new toner additives that can improve RH sensitivity while maintaining high charge.
"Surface additives also suffer from high additive impaction due to the small primary particle size of 7 to 160 m. While impaction can be reduced by using larger particle sizes, the larger particle sizes cause the additive to be less adhered to the toner surface which can lead to contamination of other surfaces, such as the photoreceptor and BCR.
"Thus, there is a need for new surface additives that can provide high charge, low RH sensitivity, and reduced additive impaction with improved adhesion of the additive to the toner surface."
As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "The present embodiments provide a toner composition comprising: toner particles comprising a resin and a colorant; and one or more surface additives applied to a surface of the toner particles, the one or more surface additives comprising titania nanotubes, titania nanosheets and mixtures thereof.
"In specific embodiments, there is provided a toner composition comprising: toner particles comprising a resin and a colorant; and one or more surface additives applied to a surface of the toner particles, the one or more surface additives comprising titania nanotubes, titania nanosheets and mixtures thereof, wherein the toner composition has a high charge of from about -15 microcoulomb per gram to about -80 microcoulomb per gram and a low relative humidity sensitivity ratio of from about 1 to about 2.
"In yet other embodiments, there is provided a developer comprising: a toner composition; and a toner carrier, the toner carrier comprising a carrier core, and a carrier coating disposed over the carrier core, wherein the toner composition comprises toner particles comprising a resin and a colorant, and one or more surface additives applied to a surface of the toner particles, the one or more surface additives comprising titania nanotubes, titania nanosheets and mixtures thereof.
BRIEF DESCRIPTION OF THE DRAWING
"The foregoing summary, embodiments, and other aspects of the present disclosure will be best understood with reference to a description of embodiments, which follows, when read in conjunction with the accompanying drawing.
"FIG. 1 shows a diagram illustrating the tetragonal structures, anatase and rutile, of titania;
"FIG. 2 shows a schematic diagram of HOMO and LUMO energies for carrier resin and toner additive when they are separated, prior to contact;
"FIG. 3 shows a schematic diagram of HOMO and LUMO energies for carrier resin and toner additive, when they are in contact, showing both a forward energy gap for negative toner charge and a reverse gap for positive toner charge; and
"FIG. 4 illustrates initial structures and the Fukui functions predicting electrophilic (f.sup.-), and nucleophilic (f.sup.+), maxima for the PMMA approach to the , ,  surfaces of/(TiO2).sub.36 designed to study the charge transfer preference for the titania nanotubes made according to the present embodiments."
For additional information on this patent application, see: VEREGIN,
Keywords for this news article include: Nanotube, Nanotechnology, Emerging Technologies, National Research Council Of Canada.
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