Apparatus and method for control or monitoring a printing system
Embodiments of the present invention relate to control apparatus and methods of a printing system, for example, comprising an intermediate transfer member (ITM) and to user-related features of a printing system. Some embodiments relate to regulation of a velocity and/or tension and/or length of the ITM. Some embodiments relate to regulation of deposition of ink on the moving ITM. Some embodiments regulate to apparatus configured to alert a user of one or more events related to operation of the ITM. Some embodiments relate to a time-line GUI for visualizing and/or manipulating queued print jobs which may be employed. Some embodiments relate to a reversed augmented reality GUI for visualization and/or control of the printing system. In some embodiments, a display screen is mounted to a printer housing and/or able to control access to moving parts of a printing system.
1. A method of operating a printing system comprising: (i) an intermediate transfer member (ITM) comprising a flexible belt; (ii) an image forming station; (iii) an impression station; and (iv) upstream and downstream rollers arranged upstream and downstream of the image forming station to define an upper run of the ITM passing through the image forming station and a lower run of the ITM passing through the impression station, the method comprising:
at the image forming station, forming ink images upon a surface of the ITM as the ITM moves;
at the impression station, periodically engaging an impression cylinder to the moving ITM to transfer the ink images from the moving ITM to substrate passing between the ITM and the impression cylinder, wherein the periodic engagements induce mechanical vibrations within slack portions in the lower run of the belt; and
applying torque to the belt by the upstream and downstream rollers in a manner maintains the upper run taut so as to substantially isolate the upper run from the mechanical vibrations in the lower run.
2. The method of claim 1 , wherein a significantly stronger torque is applied to the downstream roller than to the upstream roller.
3. The method of claim 2 wherein impression cylinder is operated to rotate, and the motion of the ITM is regulated such that:
i. at some times, the ITM moves with the same surface velocity as that of the rotating impression cylinder; and
ii. at other times, a surface velocity of the ITM is increased or decreased so as to:
A. prevent a pre-determined section of the intermediate transfer member from being aligned with the impression cylinder during periods of engagement; and/or
B. improve a synchronization between a pre-determined section of the intermediate transfer member and a pre-determined location of the impression cylinder.
4. The method of claim 1 wherein impression cylinder is operated to rotate, and the motion of the ITM is regulated such that:
i. at some times, the ITM moves with the same surface velocity as that of the rotating impression cylinder; and
ii. at other times, a surface velocity of the ITM is increased or decreased so as to:
A. prevent a pre-determined section of the intermediate transfer member from being aligned with the impression cylinder during periods of engagement; and/or
B. improve a synchronization between a pre-determined section of the intermediate transfer member and a pre-determined location of the impression cylinder.
5. The method of claim 4 , wherein the pre-determined section of the intermediate transfer member is a blanket seam.
6. The method of claim 4 , wherein the pre-determined section of the impression cylinder is a gap in the impression cylinder accommodating a substrate gripper.
7. The method of claim 4 , wherein (i) at least one of the upstream and downstream rollers is a driver roller; and (ii) the ITM is accelerated or decelerated by increasing or decreasing a rotational speed of one or more of the driver rollers during the periods of disengagement.
8. The method of claim 4 , wherein the printing system is further operated to monitor a phase difference between (i) a moving locator-point affixed to the moving ITM; and (ii) a phase of the rotating impression cylinder, and wherein the surface velocity of the ITM increases or decreases during periods of disengagement in response to the results of the phase difference monitoring.
9. The method of claim 8 , wherein the locator-point corresponds to a location of a marker on the intermediate transfer member or to a lateral formation thereof.
10. The method of claim 1 , wherein the printing system is further operated such that:
i. a circumference length of the ITM varies in time; and
ii. a circumference length of the ITM is regulated to a set-point length equal to an integral multiple of a circumference of the impression cylinder.