Image transfer for liquid electro-photographic printing
In one example, a system for transferring an ink image from a photoconductor to a print substrate includes a transfer member having a light absorbing exterior surface to receive a liquid LEP ink image from the photoconductor and to release a molten toner layer to a print substrate and a light source to expose a width of the surface carrying the liquid ink image to a light beam delivering enough power to transform the liquid ink image into a molten toner layer.
1. A system for transferring an ink image from a photoconductor to a print substrate, the system comprising:
a transfer member having a light absorbing exterior surface to receive a liquid LEP ink image from the photoconductor and to release a molten toner layer to a print substrate; and
a laser to expose a width of the surface carrying the liquid ink image to a laser beam delivering enough power to raise the temperature of the exterior surface of the transfer member at least 150° C. in less than 10 ms to transform the liquid ink image into the molten toner layer.
2. The system of claim 1 , where the laser includes multiple lasers each to simultaneously expose part of the width of the surface of the transfer member to a laser beam having an energy density at least 3 mJ/mm 2 .
3. The system of claim 1 , where the laser is to deliver enough power to heat a width of the transfer member carrying the liquid ink image to a temperature of 180° C. to 220° C. in less than 10 ms.
4. A printing process, comprising:
developing a latent image on a photoconductor into a liquid LEP ink image on the photoconductor;
transferring the liquid ink image on the photoconductor to an unheated part of a transfer member;
heating a part of the transfer member carrying the ink image to a temperature of 180° C. to 220° C. in less than 10 ms to transform the liquid ink image into a molten toner layer; and
transferring the layer to a print substrate.
5. The printing process of claim 4 , where the heating includes exposing an exterior surface of the transfer member to a laser beam.
6. The printing process of claim 5 , where the heating includes exposing an exterior surface of the transfer member to a laser beam having an energy density at least 3 mJ/mm 2 .
7. The printing process of claim 6 , where the heating includes raising the temperature of the exterior surface of the transfer member at least 150° C. in less than 10 ms.
8. The printing process of claim 7 , where the transferring begins 20 ms to 30 ms after heating.
9. A processor readable medium having instructions thereon that, when executed as part of an LEP printing process, heat a part of a transfer member carrying a liquid LEP ink image to a temperature of 180° C. to 220° C. in less than 10 ms to transform the liquid ink image into a tacky layer of toner.
10. The processor readable medium of claim 9 , where the instructions to transform include instructions that, when executed as part of an LEP printing process:
develop a latent image on a photoconductor into a liquid ink image on the photoconductor;
transfer the liquid ink image on the photoconductor to an unheated part of a transfer member; and
after the transfer member is heated, transfer the tacky layer to a print substrate.
11. The processor readable medium of claim 9 , where the instructions to heat include instructions that, when executed as part of an LEP printing process, expose an exterior surface of the transfer member to a laser beam having an energy density at least 3 mJ/mm 2 .
12. An LEP printer controller that includes the processor readable medium of claim 9 .