Intermediate transfer member for a digital printing system
A system includes: (a) a flexible intermediate transfer member (ITM) including multiple layers and markers including: (i) a structure engraved, in at least one of the layers, at respective marking locations along the ITM, and (ii) at least part of the structure is filled with a filling material that changes one or both of optical and magnetic properties of the ITM, the ITM includes an outer layer for receiving ink droplets, and transferring the ink image to a target substrate, (b) sensing assemblies disposed at respective predefined locations relative to the ITM, and configured to produce signals indicative of respective positions of the markers, and (c) a processor, which is configured to receive the signals, and based on the signals, to control a deposition of the ink droplets on the ITM, and the processor is configured to detect a deformation of the ITM based on the first and second signals.
1. A method for operating a system comprising (i) a flexible intermediate transfer member (ITM) having a stack of multiple layers and one or more markers engraved in at least one of the layers, at one or more respective marking locations along the ITM, (ii) one or more sensing assemblies disposed at one or more respective predefined locations relative to the ITM, for producing signals indicative of respective positions of the markers, (iii) one or more light sources associated respectively with at least one of the sensing assemblies, such that each light source is facing the respective sensing assembly or coupled to the respective sensor, wherein each of the light sources is for illuminating the ITM, and (iv) a slit assembly, which is disposed between the ITM and the sensing assembly and having first and second slits, which are formed at a predefined distance from one another for passing, through the slit assembly, one or more light beams emitted from the light source, the method comprising:
moving the ITM for receiving ink droplets from an ink supply system to form an ink image on the ITM, and transferring the ink image from the ITM to a target substrate;
producing (i) a first signal when a given marker of the markers is aligned with the first slit, and (ii) a second signal when the given marker is aligned with the second slit, wherein the first signal is indicative of a position of the given marker aligned with the first slit, and the second signal is indicative of the position of the given marker aligned with the second slit;
controlling a deposition of the ink droplets on the ITM based on the first and second signals; and
detecting a deformation of the ITM based on the first and second signals.
2. The method according to claim 1 , wherein at least one of the markers comprises at least one code selected from a list consisting of: a grid marker, a motion encoding code, a one-dimensional (1D) barcode, a two-dimensional (2D) barcode, and a three-dimensional (3D) barcode.
3. The method according to claim 1 , wherein moving the ITM for receiving ink droplets comprises moving the ITM at a predefined speed relative to the first and second slits, and detecting the deformation of the ITM, based on the predefined speed and the first and second signals.
4. The method according to claim 1 , wherein the system comprises at least one station or assembly, and the method comprises controlling, based on the signals, an operation of the at least one station or assembly of the system.
5. The method according to claim 4 , wherein the at least one station or assembly is selected from a list consisting of (a) an image forming station, (b) an impression station, (c) an ITM guiding system, (d) one or more drying assemblies, (e) an ITM treatment station, and (f) an image quality control station.
6. The method according to claim 5 , wherein the impression station comprises a rotatable impression cylinder and a rotatable pressure cylinder, for transferring the ink image to the target substrate, and wherein controlling the operation based on the signals comprises controlling at least one operation selected from a list consisting of (a) timing of engagement and disengagement between the impression and pressure cylinders, (b) a motion profile of at least one of the impression and pressure cylinders, and (c) a size of a gap between the disengaged impression and pressure cylinders.
7. The method according to claim 5 , wherein controlling the operation based on the signals comprises controlling at least one of: (a) a drying process applied by at least one of the drying assemblies for drying the ink droplets deposited on the ITM, (b) a velocity of one or more rollers of the ITM guiding system, (c) at least one of a cooling process, a cleaning process and a treatment process of the ITM at the ITM treatment station, or (d) at least one imaging parameter of a digital image of the ink image acquired and processed by the image quality control station.
8. The method according to claim 1 , wherein the one or more markers comprises a continuous marker formed along at least a portion of the ITM.
9. The method according to claim 1 , wherein at least one of the markers engraved in the ITM comprises filling material for filling at least part of a structure formed in at least one of the ITM layers.
10. The method according to claim 9 , wherein producing at least one of the first and second signals is based on a change caused by the filling material in one or both of: (i) at least one optical property of at least one of the ITM layers, and (ii) at least one optical property of the entire ITM.