Apparatus and method for control or monitoring a printing system

A printing system comprising:

• a. an intermediate transfer member of non-constant length;
• b. an image forming station configured to deposit ink on a surface of the intermediate transfer member while the intermediate transfer member moves so as to form ink images on the surface of the intermediate transfer member;
• c. a transfer station configured to transfer the ink images from the surface of the moving intermediate transfer member to a substrate passing in between the transfer member and an impression cylinder during a period of engagement;
• and d. electronic circuitry configured to regulate a length of the intermediate transfer member to a set-point length.

A printing system comprising:

• a. an intermediate transfer member (ITM) having a blanket seam;
• b. an image forming station configured to form ink images upon a surface of the intermediate transfer member as the intermediate transfer moves so that ink images are transported thereon to an impression station where the images are transferred from the ITM surface to substrate;
• and
• c. a sensor configured to detect times at which the blanket seam passes the sensor.

A printing system comprising:

• a. an intermediate transfer member having a blanket seam;
• b. an image forming station configured to form ink images upon a surface of the intermediate transfer member as the intermediate transfer moves so that ink images are transported thereon to an impression station where the images are transferred from the ITM surface to substrate;
• and
• wherein the formation of the ink images is controlled so that a location of the blanket seam remains in the same position relative to the printing images in consecutive rotation-cycles of the ITM.

A method of operating a printing system comprising a rotating intermediate transfer member (ITM) having a blanket seam, the method comprising:

• a. at an image forming station, forming ink images upon a surface of the intermediate transfer member as the intermediate transfer moves so that ink images are transported thereon to an impression station;
• b. at the impression station, transferring the ink images to substrate, wherein the method includes tracking at least one of:
• i. a location of the blanket seam;
• and
• ii. a relative phase difference between the blanket seam and a surface discontinuity of a rotating impression cylinder disposed at the impression station.