PRINTING ON A SUBSTRATE

Abstract: A method is disclosed for printing on a substrate where the steps include: depositing an ink on a permeable membrane, placing the membrane in juxtaposition to the surface of the substrate, and applying heat and pressure to produce a high quality color control image on the substrate.

Description: PRINTING ON A SUBSTRATE BACKGROUND OF THE INVENTION This invention relates to printing on a substrate having an absorptive and/or adsoφtive and/or bondable and/or flowable layer. More particularly, the application relates to depositing an ink on a permeable membrane, placing the membrane in juxtaposition to the surface of the substrate, and applying heat and pressure to produce a high quality color control image on the substrate. It is known to produce an image on an impermeable substrate such as aluminum by coating the aluminum with a plastic, depositing ink on a transfer sheet in a desired pattern, and thereafter placing the transfer sheet in juxtaposition to the colored substrate while applying heat and pressure. Some of the ink is transferred from the transfer sheet and bond with the plastic coating to give a printed image on the aluminum coated substrate. Such a process is described in United States Patent Application Serial No. 751 ,416, filed August 28, 1991 , and United States Patent Application Serial No. 226,949, filed April 13, 1994. Those processes were subject to the criticism that the images produced were not of consistent quality, did not, in certain cases, bond, did not have the desired resolution, brightness, and color fastness, could not be used on a substrate other than metal, and were limited to one type of polymeric coating. SUMMARY OF THE INVENTION We provide a substrate upon which a pattern is to be printed. The substrate may be an impervious material such as aluminum or thermo-setting plastic material. An absorptive and/or an adsoφtive and/or bondable surface layer is provided on the substrate. The layer may be an anodized surface on material such as aluminum or a thermo-plastic coating, or the substrate may have a surface which is adsoφtive and bondable. An ink is prepared comprising dye and pigment particles milled to be primarily smaller than about 1 1 microns. The dye when under heat and pressure is transferable into an absoφtive, bondable material in juxtaposition to the ink by a process comprising sublimation, adsoφtion, melting, entrainment, and diffusion. The ink further comprises a drier, a lubricant, and a polymer whereby a stable ink of controlled viscosity is formed. The ink is deposited on or within a permeable membrane in the pattern to be printed. There¬ after, the membrane is placed in juxtaposition to the absoφtive and/or adsoφtive bondable layer of the substrate and heat and pressure are applied to the membrane causing at least a portion of the ink matrix in the membrane to diffuse into the absoφtive, bondable layer thereby forming a second matrix comprising the first matrix and said layer. DETAILED DESCRIPTION In a preferred embodiment of the invention a color image is transferred to a substrate. The image is subjected to a color separation process and the desired number of printing plates is prepared. Each ink includes a lubricant to make the ink flowable. The ink further comprises a polymer and/or a varnish which serves as a carrier. A dye and a pigment are added to the carrier. The dye and pigment particles are milled to reduce the majority of the particles to a size range of 11 microns or less. Preferably, substantially all of the dye and pigment particles are sized below 1 1 microns. The pigment particles serve as a binder for the dye in the ink and the whole forms a matrix in which the dye and pigment are intermingled. A separate ink is prepared for each color to be used. Each ink is then transferred to a printing plate and then by the printing plate to a substrate on which the final image is to be placed either directly or through an intermediate step. A printing plate, as the term is used herein, is any device by which an ink may be transferred in a predetermined pattern to another object or surface. The printing plate may be, for example, a conventional copper plate, a stereotype plate, a transfer blanket used in lithography, or an ink jet printer programmed to deposit ink in a predetermined pattern. Preferably, each ink is deposited on or within a gas permeable membrane in the pattern to be printed The pattern is then placed in juxtaposition to the substrate The substrate may be any of a wide variety of materials having an absoφtive, adsoφtive, or bondable layer The substrate may be, for example, an essentially impervious material, such as aluminum, coated with a thermoplastic resin Alternatively, an impervious mateπal such as glass or a thermosetting resin may be coated with a thermoplastic resin to provide such a layer The substrate could also be an aluminum sheet having an anodized surface layer which is receptive to the ink After the pattern has been transferred to the gas permeable membrane, the membrane and the substrate are placed in juxtaposition in a press where they are subjected to heat and pressure, preferably in the order of 300° F or more and one psi or more The ink is believed to vaporize and/or sublime transfer- nng in part to the surface on the substrate and forming a matrix therewith. The substrate and the membrane are then removed from the press and allowed to cool, and the membrane is stπpped from the surface of the substrate Some of the ink is retained in the membrane and the pattern is easily discernible in the membrane albeit in faded form The ink deposit on the substrate is charactenzed by bπlhant colors, good color control, and precise pattern definition far in excess of pπor known practices. While we have illustrated and descπbed a present preferred embodiment of the invention, it is to be understood that the invention is not limited thereto and may be otherwise variously practiced within the scope of the following claims

Claims: WHAT IS CLAIMED IS: 1. A process for printing on a substrate having a layer which is at least one of absoφtive, an adsoφtive, and bondable surface layer which comprises: preparing an ink comprising dye and pigment, the majority of particles being uniquely sized to 1 1 microns and smaller; said dye, when under heat and pressure, being characterized by at least one of sublimation, adsoφtion, melting, functionality, molecular weight and diffusion rate into said layer when placed in juxtaposition to the dye; said pigment being characterized by its molecular control for dye dispersion; said ink also comprising a drier, a lubricant, and a polymer whereby a stable microencapsulated or polymer matrix ink of controlled viscosity is formed; depositing the ink in a form of a matrix on or within a perme¬ able membrane in the pattern to be printed; placing the membrane in juxtaposition to said layer; and applying heat and pressure to the membrane until a portion of the ink matrix in the membrane diffuses into said layer of the substrate to form a second matrix comprising a portion of the first matrix and the adsoφtive, bondable surface layer. 2. A process for printing on a non adsoφtive substrate which comprises: placing a polymeric coating on the surface of the substrate; - - preparing a colored ink comprising dye and pigment, the dye and pigment particles predominately smaller than 1 1 microns; depositing the ink in the form of a matrix on a gas permeable membrane in the pattern to be printed; placing the membrane in juxtaposition to the coated substrate; pressing the membrane against the coated substrate; applying heat and pressure to the membrane until a portion of the ink matrix in the membrane diffuses into the coating on the substrate to form a matrix therewith; and removing the membrane from the coated substrate, whereby the ink in the desired pattern is embedded in the surface coating on the substrate forming a matrix. 3. A process for printing on a substrate having an adsoφtive surface layer which comprises: preparing an ink comprising dye and pigment particles, the particles being milled to a size in the range of about 1 1 microns and smaller; depositing the ink in the form of a matrix on a gas permeable membrane in the pattern to be printed; placing the membrane in juxtaposition to the adsoφtive surface layer of the substrate; applying heat and pressure to the membrane until a portion of the ink matrix in the membrane diffuses into the adsoφtive surface layer of the substrate to form a second matrix comprising a portion of the first matrix and the adsoφtive surface layer; and removing the membrane from the adsoφtive surface layer of the substrate, whereby ink in the desired pattern is embedded in the adsoφtive surface layer on the substrate. 4. A process for printing on a substrate having a surface layer which is one of absoφtive and adsoφtive and which comprises: preparing an ink comprising dye and pigment particles, the particles being milled to a size smaller than about to 1 1 microns; said dye, when under heat and pressure, being characterized by at least one of sublimation, melting, entrainment, and diffusion into an adsoφtive material in juxtaposition to the dye; said pigment being characterized by bonding to the dye; said ink comprising a drier, a lubricant, and a varnish whereby a stable ink of controlled viscosity is formed; depositing the ink in the form of a matrix on a permeable membrane in the pattern to be printed; placing the membrane in juxtaposition to the adsoφtive surface layer of the substrate; applying heat and pressure to the membrane until a portion of the ink matrix in the membrane diffuses into the adsoφtive surface layer of the substrate to form a second matrix comprising a portion of the first matrix and the adsoφtive surface layer; and removing the membrane from the adsoφtive surface layer of the substrate, whereby ink in the desired pattern is embedded in the adsoφtive surface layer on the substrate.

Inventors: BROWN GORDON T, TRUCHAN GARY GERARD, BROWN, GORDON, T., TRUCHAN, GARY, GERARD
Applicants: HEAT IMAGE TRANSFER SYSTEM LLP, HEAT IMAGE TRANSFER SYSTEM, LLP
Application year: 1997
Main classification: B41J2
IPC codes: B41J2, B41M1, B41M5