Digital printing process
A printing system is disclosed which includes a plurality of rollers configured to support and move a loop-shaped, flexible intermediate transfer member of at least 10 meters in length along a printing system path. The printing system further includes an image forming station configured to form an image on a portion of the intermediate transfer member, and an impression station configured to enable substantial transfer of the deposited image to a substrate. The printing system also includes at least one high-speed motor associated with the plurality of rollers and configured to move the loop-shaped flexible intermediate transfer member at a speed of at least about one meter per second. Moreover, the printing system includes guiding channels configured for exerting a lateral tensioning force on the loop-shaped intermediate transfer member as it is received within the guiding channels and circulates at the speed of at least about one meter per second.
1. A printing system, comprising:
a plurality of rollers configured to support and move a loop-shaped, flexible intermediate transfer member of at least 10 meters in length along a printing system path;
an image forming station configured to retain a plurality of print heads opposite a region of the flexible intermediate transfer member and configured to enable deposit of ink droplets to form an image on a portion of the flexible intermediate transfer member;
an impression station spaced from the image forming station configured to enable substantial transfer of the deposited image to a substrate;
at least one high-speed motor associated with the plurality of rollers and configured to move the loop-shaped flexible intermediate transfer member of at least 10 meters in length at a speed of at least about one meter per second; and
guiding channels located on opposing sides of the printing system path and configured for exerting a lateral tensioning force on the loop-shaped flexible intermediate transfer member as the intermediate transfer member is received within the guiding channels and circulates at the speed of at least about one meter per second.
2. The printing system of claim 1 , wherein each of at least some of the plurality of rollers are oriented to oppose at least some of the plurality of print heads on one side of the flexible intermediate transfer member during image deposition on an opposite side of the flexible intermediate transfer member.
3. The printing system of claim 1 , wherein the plurality of rollers configured to support and move the flexible intermediate transfer member includes at least six rollers.
4. The printing system of claim 1 , wherein the plurality of rollers configured to support and move the flexible intermediate transfer member includes at least 10 rollers.
5. The printing system of claim 1 , wherein an end of the image forming station is spaced from the end of the impression station by no greater than about two meters, thereby enabling the deposited image leaving the image forming station to reach the impression station in about two seconds or less.
6. The printing system of claim 1 , wherein an end of the image forming station is spaced from the end of the impression station by no greater than about two meters, thereby enabling the deposited image leaving the image forming station to reach the impression station in about 2.5 seconds or less.
7. The printing system of claim 1 , wherein an end of the image forming station is spaced from the end of the impression station by no greater than about two meters, thereby enabling the deposited image leaving the image forming station to reach the impression station in about three seconds or less.
8. The printing system of claim 1 further comprising a drying station downstream of the image forming station and between the image forming station and the impression station, the drying station being configured to enable the deposited image to be dried in less than about two seconds while the image travels from the image forming station toward the impression station.
9. The printing system of claim 1 further comprising a drying station downstream of the image forming station and between the image forming station and the impression station, the drying station being configured to enable the deposited image to be dried in less than about 1.5 seconds while the image travels from the image forming station toward the impression station.
10. The printing system of claim 1 further comprising a drying station downstream of the image forming station and between the image forming station and the impression station, the drying station being configured to enable the deposited image to be dried in less than about a second while the image travels from the image forming station toward the impression station.
11. The printing system of claim 10 , wherein the plurality of print heads in the image forming station are configured to deposit at least a portion of a first image on the flexible image transfer member while the drying station is drying at least a portion of a second image, and while the impression station is transferring at least a portion of a third image to a substrate.
12. The printing system of claim 10 , wherein the drying station is configured to cause the flexible intermediate transfer member to reach a temperature in a first temperature range and the printing system further comprises a cooling station downstream of the impression station and between the impression station and the image forming station for retaining a coolant configured to revert the flexible intermediate transfer member to a temperature in a second temperature range, cooler than the first temperature range, by exposing the flexible intermediate transfer member to the coolant.
13. The printing system of claim 12 , wherein the first temperature range is between 80° Celsius and 220° Celsius and the second temperature range between 60° Celsius and 90°.
14. The printing system of claim 12 , wherein the at least one high-speed motor is configured to move the flexible intermediate transfer member loop along a continuous loop travel path having an upper loop region including the image forming station and the drying station, and a lower loop region including the impression station and the cooling station.
15. The printing system of claim 1 , wherein the at least one high-speed motor is configured to move the flexible intermediate transfer member at a speed of at least about 1.5 meters per second.
16. The printing system of claim 1 , wherein the at least one high-speed motor is configured to move the intermediate transfer member at a speed of at least about 2 meters per second.
17. The printing system of claim 1 , wherein the at least one high-speed motor is configured to move the intermediate transfer member at a speed of at least about 3 meters per second.
18. The printing system of claim 1 , wherein the flexible intermediate transfer member is more than 10 meters in length and the at least one high-speed motor configured to move the flexible intermediate transfer member loop such that a cycle is completed in less than 5 seconds.
19. A printing method, comprising:
rotating, about a travel path, a flexible intermediate transfer member arranged in a loop, wherein a length of the loop is at least 10 meters;
laterally stretching, during rotating, the flexible intermediate transfer member to exert a lateral tension on the intermediate transfer member transverse to a direction of travel about the travel path;
depositing ink droplets, with a plurality of print heads opposite a region of the laterally stretched flexible intermediate transfer member, to form an image on a portion of the laterally stretched flexible intermediate transfer member;
transferring the deposited image from the laterally stretched intermediate transfer member to a substrate; and
moving the laterally stretched flexible intermediate transfer member loop of at least 10 meters in length at a speed of at least about one meter per second.
20. The method of claim 19 , wherein the intermediate transfer member is at least twice as flexible in a lateral direction than in a direction of the intermediate transfer member travel.
21. The method of claim 19 , wherein the flexible intermediate transfer member is more than 10 meters in length and the method further includes moving the flexible intermediate transfer member loop such that a cycle is completed in less than five seconds.