Backlit printing
A method and apparatus for printing digital ink jet images to be backlit by a light source is provided. Such backlit printing relies upon additional color pigment to be hidden in the white layer to add additional color density to the image as the back light source passes light through the layers. Print heads are divided into a region of multiple single color print head arrays and a region of white and color print region printed over a color print region. Such backlit printing may be used on both first surface printing and second surface printing. When such backlit printing is used, it may not be necessary to divide the print heads exactly in half as one layer may require less print nozzles than the other as the interlacing and or DPIs may vary for the different layers.
1. A multi-pass printing method comprising:
printing a first multi-color image including a combination of colors on a substantially translucent or transparent substrate using a first group of ink jets within a print head array on a print carriage during a first pass of the carriage, wherein the first group of ink jets contains the colors necessary to print the first multi-color image, wherein the substantially translucent or transparent substrate has a first side and a second side, and wherein the first multi-color image is printed on the second side; and
printing an at least partially opaque coating layer over the first multi-color image using a second group of ink jets during a subsequent pass of the carriage, wherein the at least partially opaque coating layer comprises a layer of ink, the layer of ink comprising a combination of white ink and process inks, wherein the at least partially opaque coating layer comprises a second multi-color image in the form of but with less intensity than the first multi-color image, wherein the first group of ink jets and the second group of ink jets are both configured in the printer carriage, and wherein the at least partially opaque coating layer enables viewing of the first multi-color image from the first side of the substantially translucent or transparent substrate both (a) when ambient lighting is at a level above a back lit source and (b) when back light is at a level above ambient lighting.
2. The method of claim 1 , wherein the substrate comprises plastic.
3. The method of claim 1 , wherein the substrate comprises glass.
4. The method of claim 1 , wherein the first group of ink jets comprises substantially one half of the ink jets in the print head array in the printer carriage.
5. The method of claim 1 , wherein the second group of ink jets comprises substantially one half of the ink jets in the print head array in the printer carriage.
6. The method of claim 1 , further comprising moving the printer head carriage on an axis in a direction of travel back and forth across the substrate.
7. A printing apparatus comprising:
a processor;
a group of ink jets within a print head array on a print carriage controlled by the processor to print a first multi-color image including a combination of colors on a substantially translucent or transparent substrate during a first pass of the carriage, wherein the first group of ink jets contains the colors necessary to print the first multi-color image, wherein the substantially translucent or transparent substrate has a first side and a second side, and wherein the first multi-color image is printed on the second side; and
a second group of ink jets controlled by the processor to print an at least partially opaque coating layer over the first multi-color image during a subsequent pass of the carriage, wherein the at least partially opaque coating layer comprises a layer of ink, the layer of ink comprising a combination of white ink and process inks, wherein the process inks form a second multi-color image in the form of but with less intensity than the first multi-color image, wherein the first group of ink jets and the second group of ink jets are both configured in the print carriage, and wherein the at least partially opaque coating layer enables viewing of the first multi-color image from the first side of the substantially translucent or transparent substrate both (a) when ambient lighting is at a level above the back lit source and (b) when the back light is at a level above ambient lighting.
8. The apparatus of claim 7 , wherein the substrate comprises plastic.
9. The apparatus of claim 7 , wherein the substrate comprises glass.
10. The apparatus of claim 7 , wherein the first group of ink jets comprises substantially one half of the ink jets in the print head array in the printer carriage.
11. The apparatus of claim 7 , wherein the second group of ink jets comprises substantially one half of the ink jets in the print head array in the printer carriage.
12. The apparatus of claim 7 , wherein the printer head carriage moves on an axis in a direction of travel back and forth across the substrate.
13. A multi-pass printing method comprising:
printing a first multi-color image including a combination of colors on a substantially translucent or transparent substrate using a first group of ink jets within a print head array on a print carriage during a first pass of the carriage, wherein the first group of ink jets contains the colors necessary to print the first multi-color image, wherein the substantially translucent or transparent substrate has a first side and a second side, and wherein the first multi-color image is printed on the second side; and
printing an at least partially opaque coating layer over the first multi-color image using a second group of ink jets during a subsequent pass of the carriage, wherein the at least partially opaque coating layer comprises a layer of ink, the layer of ink comprising a combination of white ink and process inks, wherein the process inks form a second multi-color image different from and with less intensity than the first multi-color image, wherein the first group of ink jets and the second group of ink jets are both configured in the printer carriage, and wherein the at least partially opaque coating layer causes a resulting backlit image to be different from a resulting image that is not backlit.
14. A printing apparatus comprising:
a processor;
a group of ink jets within a print head array on a print carriage controlled by the processor to print a first multi-color image including a combination of colors on a substantially translucent or transparent substrate during a first pass of the carriage, wherein the first group of ink jets contains the colors necessary to print the first multi-color image, wherein the substantially translucent or transparent substrate has a first side and a second side, and wherein the first multi-color image is printed on the second side; and
a second group of ink jets controlled by the processor to print an at least partially opaque coating layer over the first multi-color image during a subsequent pass of the carriage, wherein the at least partially opaque coating layer comprises a layer of ink, the layer of ink comprising a combination of white ink and process inks, wherein the process inks form a second multi-color image different from and with less intensity than the first multi-color image, wherein the first group of ink jets and the second group of ink jets are both configured in the printer carriage, and wherein the at least partially opaque coating layer causes a resulting backlit image to be different from a resulting image that is not backlit.