Ceramic coating composition for a hybrid scavengeless development donor roll
AssigneeXerox Corporation
InventorsAnn M. Kazakos, Daniel R. Gilmore, III
Life of this patent
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Abstract
A donor roll having a ceramic coating for use with an electrode structure in a scavengeless development unit of an electrostatographic printer. The ceramic coating consist essentially of a suitable mixture of alumina and titania by weight giving the donor roll a desired resistivity within a range of 2.0.times.10.sup.7 -4.2.times.10.sup.8 (Ohm-cm), a discharge time constant of about 550 microseconds, and a dielectric constant within a range of 16-24 at 100.KHz.
Claims14
A toner donor roll for use in a development apparatus, the donor roll comprising:
- (a) a conductive core;
- and
- (b) a ceramic outer coating over said-conductive core, said ceramic coating consisting essentially of a mixture of alumina and titania by weight, for giving the toner transport donor roll a desired resistivity within a range of 2.8.times.10.sup.7 -2.1.0.times.10.sup.9 (Ohm-cm), and a dielectric constant within a range of 16-24 at 100. KHz.
A developer material transport roll comprising:
- (a) a core;
- and
- (b) a ceramic coating over said core, said ceramic coating comprising 85%-88% Alumina and at least 13% Titania by weight for giving the developer material transport roll a desired resistivity within a range of 2.8.times.10.sup.7 -2.1.0.times.10.sup.9 (Ohm-cm), and a discharge time constant of about 550 microseconds measured with an oscilloscope.
An apparatus for developing a latent electrostatic image on a surface, the apparatus comprising:
- (a) a housing defining a chamber storing developer material containing toner particles;
- (b) means mounted partially within said chamber for moving said developer material;
- and
- (c) a rotatable donor roll for transporting toner particles into a development transfer relationship with the latent electrostatic image on the surface, said donor roll being mounted in a toner particle receiving relationship with said developer material moving means, said donor roll including a core, and a ceramic outer coating, and said ceramic coating consisting of 85%-88% Alumina (Al.sub.2 O.sub.3) and 13%-14.5% Titania (TiO.sub.2), by weight.
A toner donor roll for use in a development apparatus, the donor roll comprising:
- (a) a conductive core;
- and
- (b) a ceramic outer coating over said conductive core, said ceramic coating consisting essentially of a mixture of alumina and titania by weight, for giving the toner transport donor roll a desired resistivity within a range of 2.8.times.10.sup.7 -2.1.times.10.sup.9 (Ohm-cm), a dielectric constant within a range of 16-24 at 100. KHz and an oscilloscope-measured discharge time constant within a range of 60-600 microseconds.
A printing machine comprising:
- (a) an image bearing surface;
- (b) means for electrostatically forming a latent image on said image bearing surface;
- and
- (c) a development apparatus for developing the latent electrostatic image, the development apparatus including:
- (i) a housing defining a chamber storing developer material containing toner particles;
- (ii) means mounted partially within said chamber for moving said developer material;
- and
- (iii) a rotatable donor roll for transporting toner particles into a development transfer relationship with the latent electrostatic image on the image bearing surface, said donor roll being mounted in a toner particle receiving relationship with said developer material moving means, said donor roll including a core, and a ceramic outer coating, and said ceramic outer coating consisting essentially of 85%-88% Alumina (Al.sub.2 O.sub.3) and 13%-14.5% Titania (TiO.sub.2), by weight.
Dependencies are inferred from the claim text.