Preparing color toner images with metallic effect

1. A method for providing a color image with a metallic effect, the method comprising:

forming one or more latent images,

developing the one or more latent images with non-conductive metallic dry toner particles and color toner particles to form a developed color toner image with a metallic effect,

transferring the developed color toner image with a metallic effect to a receiver material to form a transferred developed color toner image with a metallic effect, and

fixing the transferred developed color toner image with a metallic effect to the receiver material,

wherein each non-conductive metallic dry toner particle consists essentially of a polymeric binder phase and non-conductive metal oxide particles dispersed within the polymeric binder phase and each non-conductive metallic dry toner particle is free of additional colorants,

wherein, before fixing:

(a) each non-conductive metallic dry toner particle has a mean volume weighted diameter (D vol ) of at least 15 μm and up to and including 40 μm and an aspect ratio of at least 2 and up to and including 10,

(b) at least 50 weight % of the total non-conductive metal oxide particles within the non-conductive metallic dry toner particles have an aspect ratio of at least 5 and an ECD of at least 2 μm and up to and including 50 μm,

(c) the non-conductive metal oxide particles are present in an amount of at least 20 weight % and up to and including 50 weight %, based on total non-conductive metallic dry toner particle weight,

(d) the ratio of the non-conductive metallic dry toner particle D vol to the average equivalent circular diameter (ECD) of the non-conductive metal oxide particles in the non-conductive metallic dry toner particles, before fixing, is greater than 0.1 and up to and including 10,

(e) the non-conductive metal oxide particles consist essentially of: (i) a silica, alumina, or mica substrate having an outer surface, and (ii) disposed on at least part of the substrate outer surface, one or more layers of an oxide of iron, chromium, silicon, titanium, or aluminum, each of the one or more layers having an average dry layer thickness of at least 30 nm and up to and including 700 nm so that the total average dry thickness of all oxide layers is at least 30 nm and up to and including 1400 nm, and

(f) at least one of the layers of an oxide of iron, chromium, silicon, titanium, or aluminum, forms the outermost layer of the non-conductive metal oxide particles.

2. The method of claim 1 , wherein the color toner particles comprise a polymeric binder phase and a cyan, yellow, magenta, or black colorant dispersed within the polymeric binder phase.

3. The method of claim 1 , comprising:

forming the toner image that provides a metallic effect on the receiver material with the non-conductive metallic dry toner particles,

then forming a cyan, yellow, magenta, or black toner image over the toner image that provides a metallic effect, with the color toner particles, and

fixing both the toner image that provides a metallic effect and the cyan, yellow, magenta, or black toner image to the receiver material.

4. The method of claim 1 , comprising:

forming a cyan, yellow, magenta, or black toner image on a receiver material,

then forming the toner image that provides a metallic effect over the cyan, yellow, magenta, or black toner image, and

fixing both the cyan, yellow, magenta, or black image and the toner image that provides a metallic effect to the receiver material.

5. The method of claim 1 , comprising:

forming, in any sequence, cyan, yellow, magenta, and black toner images on a receiver material,

then forming the toner image that provides a metallic effect over the cyan, yellow, magenta, and black toner images, and

fixing all of the cyan, yellow, magenta, and black toner images, and the toner image that provides a metallic effect to the receiver material.

6. The method of claim 1 , comprising:

forming, the toner image that provides a metallic effect on the receiver material,

then forming in this sequence, black, yellow, magenta, and cyan toner images over the toner image that provides a metallic effect, and

fixing all of the black, yellow, magenta, and cyan toner images, and the toner image that provides a metallic effect to the receiver material.

7. The method of claim 1 , comprising:

forming in this sequence, black, yellow, and magenta toner images on the receiver material,

then forming the toner image that provides a metallic effect over the black, yellow, and magenta toner images,

then forming a cyan toner image over the toner image that provides a metallic effect and the black, yellow, and magenta toner images, and

fixing all of the black, yellow, and magenta toner images, the toner image that provides a metallic effect, and the cyan toner image, to the receiver material.

8. The method of claim 1 , wherein the lay down of the non-conductive metallic dry toner particles in the toner image that provides a metallic effect is defined by the equation, in mg/cm 2 :

Lay down≦[0.06× D vol ].

9. The method of claim 1 , wherein the non-conductive metal oxide particles consist essentially of: (i) a silica, alumina, or mica substrate having an outer surface, and (ii) disposed on at least part of the substrate outer surface, one or more layers of an oxide of iron, chromium, silicon, titanium, or aluminum, each of the one or more layers having an average dry layer thickness of at least 60 nm and up to and including 300 nm so that the total average dry thickness of all oxide layers is at least 60 nm and up to and including 600 nm.

10. The method of claim 1 , wherein the non-conductive metal oxide particles consist essentially of: (i) a silica, alumina, or mica substrate having an outer surface, and (ii) disposed on at least part of the substrate outer surface, two layers of different oxides of iron, chromium, silicon, titanium, or aluminum, each of the two layers having an average dry layer thickness of at least 60 nm and up to and including 300 nm so that the total average dry thickness of both oxide layers is at least 60 nm and up to and including 600 nm.

11. The method of claim 1 , wherein at least one dry layer disposed on the silica, alumina, or mica substrate comprises titanium dioxide, ferric oxide, or chromium oxide, or mixtures thereof.

12. The method of claim 1 , wherein the non-conductive metal oxide particles consist essentially of a mica substrate having an outer surface, and a titanium dioxide layer, ferric oxide layer, or both a titanium dioxide layer and a ferric oxide layer disposed on at least part of the substrate outer surface.

13. The method of claim 1 , wherein a silane is disposed on the outer surface of the non-conductive metal oxide particles in an amount of up to 5% based on the total weight of the non-conductive metal oxide particles.

14. The method of claim 1 , wherein the ratio of the non-conductive metallic dry toner particle D vol to the average equivalent circular diameter (ECD) of the non-conductive metal oxide particles in the non-conductive metallic dry toner particles, before fixing, is greater than 0.1 and up to and including 5.

15. The method of claim 1 , wherein the non-conductive metallic dry toner particles have an aspect ratio of at least 3.

16. The method of claim 1 , wherein the non-conductive metallic dry toner particles further comprise, on their outer surface, a fuser release aid, flow additive particles, or both of these materials.

17. The method of claim 1 , wherein the receiver material is a sheet of paper or a polymeric film.

18. The method of claim 1 , comprising forming cyan, yellow, magenta, and black toner images, and the toner image that provides a metallic effect, on the receiver material using at least five sequential toner printing stations in a color electrophotographic printing machine.