Apparatus and method for control or monitoring a printing system

A printing system comprising:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• and
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers, wherein the ITM is a flexible blanket having lateral projections along each edge that are received in guide channels of the printing system to maintain the blanket under lateral tension, wherein an irregularity in the spacing of the lateral projections serves as a marker.

A printing system comprising:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• and
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers, wherein the markings are located on one or both lateral edges of the ITM at locations outside the area of the ITM that passes beneath the print bars.

A printing system compriing:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers;
• and
• d. electronic circuitry configured to monitor, in accordance with output of the marker-detector, temporal fluctuations of non-uniform stretching of the circulating ITM.

A printing system comprising:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers;
• and
• d. electronic circuitry configured to determine, in accordance with output of the marker-detector, variations in the length of the circulating ITM.

A printing system comprising:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers;
• and
• d. electronic circuitry for measuring a local ITM velocity of the circulating ITM in accordance with output of the marker-detector.

A printing system comprising:

• a. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• b. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar;
• c. a marker-detector associated with the print-bar and configured to detect movement of the markers;
• and
• d. electronic circuitry for measuring a local ITM stretch of the circulating ITM in accordance with output of the marker-detector.

A method of monitoring an operating parameter, the method comprising:

• a. providing a printing system comprising:
• A. an intermediate transfer member (ITM) having a plurality of markers, each marker being disposed at a different respective location on the ITM;
• B. an image forming station including a print bar disposed over the ITM and configured to form ink-images by deposition of droplets of ink on a surface of the ITM while the ITM circulates past the print bar, and
• B. a marker-detector associated with the print-bar and configured to detect movement of the markers;
• and
• b. monitoring, in accordance with the output of the marker detector, at least one operating parameter selected from the group consisting of:
• (i) temporal fluctuations of non-uniform stretching of the circulating ITM;
• (ii) variations in the length of the circulating ITM;
• (iii) a local ITM velocity of the circulating ITM;
• (iv) irregularities in the speed of movement of the ITM;
• and (v) local ITM stretch of the circulating ITM.