There is disclosed a method of printing onto the surface of a substrate, which method comprises i) coating a donor surface (12) with a monolayer of particles, ii) treating the substrate surface (80) to render at least selected regions tacky, and iii) contacting the substrate surface with the donor surface to cause particles to transfer from the donor surface only to the tacky regions of the substrate surface. After printing on a substrate (20), the donor surface (12) returns to the coating station (14) where the continuity of the monolayer is restored by recovering with fresh particles the regions of the donor surface exposed by the transfer of particles to the substrate.

An apparatus for coating a donor surface that is movable relative to the apparatus with a layer of thermoplastic particles, the particles adhering more strongly to the surface than to one another. The apparatus comprises an application device to apply to the donor surface a fluid stream within which the particles are suspended, a housing surrounds the application device forming an interior plenum for confining the fluid stream, the housing prevents egress of particles from a sealing gap defined between the rim of the housing and the surface to be coated, and a suction source connected to the housing to extract from the plenum excess fluid and particles. In operation, the suction source extracts substantially all particles that are not in direct contact with the donor surface, leaving substantially a single particle layer adhering to the donor surface upon exiting the apparatus.

A printer system includes a memory, a processor, and one or more printer heads. The processor determines a number of transmission layers and a number of barrier layers to use in a color changing expiration indicator based at least in part on a time period between a print date of the indicator and a received expiration date. The printer heads print a reactive layer onto print media, where at least a portion of the reactive layer is configured to migrate through the transmission layers. The printer heads also print the determined number of transmission layers and the determined number of barrier layers in alternation. The printer heads print a reactant layer that is configured to change color responsive to a reaction between the reactant layer and the reactive layer upon migration of the reactive layer through the transmission layers. The reaction is configured to occur on the received expiration date.

A kit for making an imprint of a surface of a fish without pigmented ink is disclosed. The kit comprises a developer-coated paper having a developer agent, a nonpigmented activation solution having an activation agent, an applicator, and a set of instructions for applying the activation solution to the surface of the fish with the applicator and making an imprint of the surface of the fish on the developer-coated paper. The developer agent and activation agent are selected so that they produce color when they are combined.

A leuco dye pastel marking device for use with a substrate treated with an activator of the leuco dye, such that drawing upon the substrate will reveal a color, but drawing on a normal surface will have no visible effect. A solvent such as dimethyl adipate is used to store the leuco dye in a longer-lived, more stable, solid form, and varying hardnesses and consistencies may be achieved by the addition of 12 hydroxystearic acid and ethyl cellulose. The substrate may be treated selectively with the activator such that a texture, image, or hidden message is revealed by the application of the leuco dye pastel to the substrate. One or more substrates and one or more leuco dye pastel marking devices may be presented to a child as a coloring book with pastels that only visibly mark the coloring book and no other surface.

A method includes printing, by one or more printer heads of the printing system, a reactive layer onto print media. The method also includes printing, by the one or more printer heads, a determined number of transmission layers and a determined number of barrier layers in alternation with one another. At least a portion of the reactive layer is configured to migrate through the transmission layers. The method further includes printing, by the one or more printer heads, a reactant layer that is configured to change color responsive to a reaction that occurs between the reactant layer and the reactive layer upon migration of the reactive layer through the determined number of transmission layers. The reaction is configured to occur on a received expiration date.

There is disclosed a method of printing onto the surface of a substrate, which method comprises i) coating a donor surface with a monolayer of particles, ii) treating the substrate surface to render at least selected regions tacky, and iii) contacting the substrate surface with the donor surface to cause particles to transfer from the donor surface only to the tacky regions of the substrate surface. After printing on a substrate, the donor surface returns to the coating station where the continuity of the monolayer is restored by recovering with fresh particles the regions of the donor surface exposed by the transfer of particles to the substrate.

A marking system includes a composition having at least one color precursor, a moldable substrate having a color developer, and a marking instrument for applying the composition to the moldable substrate to form at least one mark on the moldable substrate. A method of producing a colored three-dimensional molded object includes the steps of manipulating a moldable substrate having a color developer into a molded shape having an outer surface; and applying, on the outer surface of the molded shape, a first composition having at least one color precursor to a first portion of the molded shape.

The present invention relates to a process for making an etched pattern comprising a step of depositing onto a printable metal surface droplets of an ink composition provided by a printing method, wherein the ink composition comprises a first ink vehicle being water, a second ink vehicle being an organic compound and an etchant being an acid or abase according to the Brnsted definition, characterized in that the ink composition has a pH in the range of from (0) to (4) or from (9) to (14). The invention further relates to substrates having a metal surface with an etched pattern, to the use of such substrates in various applications, to articles comprising the inventive substrate and to the use of the inventive process for the production of metal products.

An apparatus is disclosed for coating a surface that is movable relative to the apparatus with a layer of metallic particles or particles having a metal-like appearance and reflectivity, the particles adhering more strongly to the surface than to one another. The apparatus comprises at least one spray head for directly or indirectly applying to the surface a fluid stream within which the particles are suspended, a housing surrounding the spray head(s) and defining an interior plenum for confining the fluid stream, the housing having a rim adjacent the surface that is configured to prevent egress of particles from a sealing gap defined between the rim of the housing and the surface to be coated, and a suction source connected to the housing to extract from the plenum the sprayed fluid and particles suspended in the sprayed fluid. In operation, the suction source extracts substantially all particles that are not in direct contact with the surface, so as to leave only a substantially single particle layer adhering to the surface on exiting the apparatus.