INKJET PRINTING SYSTEMS AND METHODS FOR CONTROLLED, NON-IMAGING INKJET PURGING
Provided herein are inkjet printing systems and methods for preventing inkjet degradation in such inkjet printing systems. The systems and methods described herein may be applied to a number of different types of printing systems, but may find particular application in connection with cut-sheet production inkjet printing systems relying on a continuous short edge printing. According to various embodiments, the printing systems include one or more printheads staggered in a cross-process direction and a media transport module configured to collect non-imaging ink droplets jetted from unused inkjets.
1 . A method for preserving inkjet health in an inkjet printing system comprising a media transport module configured to transport a print media substrate through a print zone and an inkjet printhead configured to eject ink droplets from one or more inkjet nozzles in the print zone, the method comprising:
detecting, via the inkjet printing system, a position of a transport belt of the media transport module;
determining, based on the detected position of the transport belt, a location of a low-stick purge device of the media transport module, wherein the low-stick purge device is disposed on and/or embedded in the transport belt; and
ejecting, from a first inkjet nozzle of the one or more inkjet nozzles, one or more ink droplets based on the determined location of the low-stick purge device of the media transport module, wherein the one or more ink droplets are ejected onto the low-stick purge device of the media transport module as the low-stick purge device moves through the print zone of the inkjet printing system.
2 . The method of claim 1 , wherein the transport belt comprises a plurality of vacuum belt holes arranged in a hole pattern, and
wherein the low-stick purge device of the media transport module does not include any of the plurality of vacuum belt holes.
3 . The method of claim 1 , wherein the low-stick purge device of the media transport module comprises a strip of material coupled to the transport belt.
4 . The method of claim 3 , wherein the strip of material has a thickness of less than about 50 μm.
5 . The method of claim 1 , wherein the low-stick purge device of the media transport module is embedded into the transport belt such that the low-stick purge device and the transport belt have a substantially uniform thickness.
6 . The method of claim 1 , wherein the low-stick purge device of the media transport module has a surface energy of less than about 30 mJ/m 2 .
7 . The method of claim 6 , wherein the low-stick purge device of the media transport module has a surface energy of less than about 20 mJ/m 2 .
8 . The method of claim 1 , comprising:
receiving, by the inkjet printing system, a print job to be completed by the inkjet printing system;
completing the print job by:
transporting one or more print media substrates through the print zone based on the received print job; and
ejecting, from the one or more inkjet nozzles of the printhead, a plurality of ink droplets onto the one or more print media substrates within the print zone; and
while completing the print job:
determining, based on the print job, an inactive inkjet nozzle among the one or more inkjet nozzles, wherein the inactive inkjet nozzle is the first inkjet nozzle; and
ejecting, from the inactive inkjet nozzle, the one or more ink droplets based on the determined location of the low-stick purge device of the media transport module, wherein the one or more ink droplets are non-imaging ink droplets.
9 . The method of claim 8 , wherein the inactive inkjet nozzle is determined by:
calculating a projected duration of non-use for at least some of the one or more inkjet nozzles during the print job; and
identifying which of the one or more inkjet nozzles having a projected duration of non-use that exceeds a threshold, wherein at least one inkjet nozzle has a projected duration of non-use that exceeds the threshold and is identified as the inactive inkjet nozzle.
10 . The method of claim 1 , wherein the inkjet printing system comprises a belt registration sensor, and the position of a transport belt is detected using the belt registration sensor.
11 . An inkjet printing system comprising:
a media transport module comprising a transport belt and configured to transport a print media substrate through a print zone of the inkjet printing system, wherein the media transport module comprises a low-stick purge device disposed on and/or embedded in the transport belt;
an inkjet printhead comprising a plurality of inkjet nozzles and configured to eject ink droplets from the plurality of inkjet nozzles in the print zone; and
a print engine operatively connected to the media transport module and the inkjet printhead, wherein the print engine comprises one or more processors in communication with a non-transitory computer-readable storage medium having stored thereon instructions that, when executed by the one or more processors, cause the inkjet printing system to perform the following operations:
detect a position of a transport belt of the media transport module;
determine, based on the detected position of the transport belt, a location of the low-stick purge device of the media transport module; and
eject, from a first inkjet nozzle of the plurality of inkjet nozzles, one or more ink droplets based on the determined location of the low-stick purge device of the media transport module, wherein the one or more ink droplets are ejected onto the low-stick purge device as the low-stick purge device moves through the print zone of the inkjet printing system.
12 . The inkjet printing system of claim 11 , wherein the transport belt comprises a plurality of vacuum belt holes arranged in a hole pattern, and
wherein the low-stick purge device of the media transport module does not include any vacuum belt holes.
13 . The inkjet printing system of claim 11 , wherein the low-stick purge device of the media transport module comprises a strip of material coupled to the transport belt.
14 . The inkjet printing system of claim 13 , wherein the strip of material has a thickness of less than about 50 μm.
15 . The inkjet printing system of claim 11 , wherein the low-stick purge device of the media transport module is embedded into the transport belt such that the transport belt and the low-stick purge device have a substantially uniform thickness.
16 . The inkjet printing system of claim 11 , wherein the low-stick purge device of the media transport module has a surface energy of less than about 30 mJ/m 2 .
17 . The inkjet printing system of claim 16 , wherein the low-stick purge device of the media transport module has a surface energy of less than about 20 mJ/m 2 .
18 . The inkjet printing system of claim 11 , wherein the low-stick purge device extends across at least a portion of the transport belt in a cross-process direction corresponding to an inboard portion of the printhead, and/or
wherein the low-stick purge device extends across an entire width of the transport belt.
19 . A media transport module for use in an inkjet printing system, the media transport module comprising:
a transport belt comprising a plurality of vacuum belt holes, wherein the transport belt is configured to transport a print media substrate through a print zone of the inkjet printing system; and
a low-stick purge device having a surface energy less than a surface energy of the transport belt;
wherein the low-stick purge device of the media transport module does not include any of the plurality of vacuum belt holes.
20 . The media transport module of claim 19 , wherein the low-stick purge device of the media transport module comprises a strip of material coupled to the transport belt, and/or
wherein the low-stick purge device of the media transport module is embedded into the transport belt such that the low-stick purge device such that the transport belt has a substantially uniform thickness.