Landa Corporation Ltd.

A method including receiving a first signal indicative of a first electrical current measured on a first motion assembly ( 77 ) for moving a flexible substrate ( 44 ) that receives droplets of a printing fluid from an image forming station ( 60 ) to form an image thereon. A second signal indicative of a second electrical current measured on a second motion assembly ( 99 ) for moving the flexible substrate ( 44 ), is received, wherein a section of the flexible substrate ( 44 ) is moving between the first motion assembly ( 77 ) and the second motion assembly ( 99 ). A parameter, which is indicative of a distortion in the image, is calculated based on the first signal and the second signal. In response to detecting, based on the parameter, an increase in the distortion, a corrective action is applied to reduce the distortion.

A system and method for performing quality control in a digital printing system (DPS) is provided. The DPS includes an impression station for transferring an ink image from a surface of an intermediate transfer member to a substrate. The impression station includes an impression cylinder housing one or more grippers operable to grasp and hold a leading edge of the substrate as it passes through the DPS, for conveying the substrate along the impression cylinder during the transfer of the ink image. An imaging device is operable, during advancement of the substrate on the impression cylinder, to capture a digital image including a region of interest (ROI) that is associated with at least a portion of the grippers and at least a portion of the substrate. A controller is configured, based on the digital image, to indicate an error in a position of the substrate relative to the grippers.

A digital printing system includes an intermediate transfer member (ITM), to receive a printing fluid to form an image, a continuous target substrate having opposing first surface and second surface, a light source to illuminate the first surface, and an image sensor to image at least a portion of the light transmitted through the target substrate to the second surface, and a processor. The target substrate configured to engage with the ITM at an engagement point for receiving the image from the ITM, and at the engagement point, the ITM is configured to move at a first velocity and the target substrate is configured to move at a second velocity. The processor is configured to produce a digital image based on the electrical signals, and to estimate, based on the digital image, at least a distortion in the image.

A printing method includes producing a first image at a first position ( 16 a, 23 a ) on a movable intermediate transfer member (ITM) ( 44 ) of a printing system ( 10 ), and moving the ITM ( 44 ) for transferring the first image to a first substrate ( 50 ). For a second image that is intended to be produced on the ITM ( 44 ) at a second position ( 16 b, 23 b ) different from the first position ( 16 a, 23 a ): (i) a deliberate offset ( 18, 24 ) of the second position ( 16 b, 23 b ) relative to the first position ( 16 a, 23 a ), is specified, (ii) a movement of the ITM ( 44 ) that would at least partially compensate for the offset ( 18, 24 ) when transferring the second image to a second substrate ( 50 ), is calculated, and (iii) the second image is produced and the ITM ( 44 ) is moved in accordance with the calculated movement, for transferring the second image to the second substrate ( 50 ).

A method for correcting distortion in image printing, the method includes receiving a digital image ( 200, 306, 376, 500, 600, 700, 810 ) acquired from a printed image. Based on the digital image ( 200, 306, 376, 500, 600, 700, 810 ), a geometric distortion in the printed image is estimated. One or more pixel locations ( 228, 504, 506, 514, 610, 620, 630, 640, 712, 716, 722, 724 ) are calculated, such that, when one or more dummy pixels ( 232, 234 ) are implanted therein, compensate for the estimated geometric distortion. The geometric distortion is corrected in a subsequent digital image to be printed, by implanting the one or more dummy pixels ( 232, 234 ) at the one or more calculated pixel locations ( 228, 504, 506, 514, 610, 620, 630, 640, 712, 716, 722, 724 ) in the subsequent digital image. The subsequent digital image having the corrected geometric distortion is printed.

A digital printing system ( 10 ) includes a flexible substrate ( 44 ), an optical assembly ( 200, 301 ) and a processor ( 20 ). The flexible substrate ( 44 ) has a periodic pattern, and is configured to be moved and to receive ink droplets in a printing process that forms an image thereon. The optical assembly ( 200, 301 ) is configured to illuminate the flexible substrate ( 44 ) with light ( 215, 315 ), to detect the light ( 215, 315 ) from the flexible substrate ( 44 ), and to derive from the detected light ( 215, 315 ) a signal indicative of the periodic pattern. The processor ( 20 ) is configured to receive the signal and to monitor or control the digital printing system ( 10 ) based on the periodic pattern as indicated by the signal.

A method including receiving a first signal indicative of a first electrical current measured on a first motion assembly ( 77 ) for moving a flexible substrate ( 44 ) that receives droplets of a printing fluid from an image forming station ( 60 ) to form an image thereon. A second signal indicative of a second electrical current measured on a second motion assembly ( 99 ) for moving the flexible substrate ( 44 ), is received, wherein a section of the flexible substrate ( 44 ) is moving between the first motion assembly ( 77 ) and the second motion assembly ( 99 ). A parameter, which is indicative of a distortion in the image, is calculated based on the first signal and the second signal. In response to detecting, based on the parameter, an increase in the distortion, a corrective action is applied to reduce the distortion.

A digital printing system ( 10 ) includes a flexible substrate ( 44 ), an optical assembly ( 200, 301 ) and a processor ( 20 ). The flexible substrate ( 44 ) has a periodic pattern, and is configured to be moved and to receive ink droplets in a printing process that forms an image thereon. The optical assembly ( 200, 301 ) is configured to illuminate the flexible substrate ( 44 ) with light ( 215, 315 ), to detect the light ( 215, 315 ) from the flexible substrate ( 44 ), and to derive from the detected light ( 215, 315 ) a signal indicative of the periodic pattern. The processor ( 20 ) is configured to receive the signal and to monitor or control the digital printing system ( 10 ) based on the periodic pattern as indicated by the signal.

A digital printing system includes an intermediate transfer member (ITM), to receive a printing fluid to form an image, a continuous target substrate having opposing first surface and second surface, a light source to illuminate the first surface, and an image sensor to image at least a portion of the light transmitted through the target substrate to the second surface, and a processor. The target substrate configured to engage with the ITM at an engagement point for receiving the image from the ITM, and at the engagement point, the ITM is configured to move at a first velocity and the target substrate is configured to move at a second velocity. The processor is configured to produce a digital image based on the electrical signals, and to estimate, based on the digital image, at least a distortion in the image.

Printing apparatus ( 20 ) includes a continuous blanket ( 24 ) and a set of motorized rollers ( 31 ), which advance the blanket at constant speed through an image area. Print bars ( 38 ) eject droplets of ink at respective locations onto the blanket in the image area. Monitoring rollers ( 42 ), in proximity to the locations of the print bars, contact the blanket to be rotated by blanket advancement. Each monitoring roller includes an encoder ( 44 ), which outputs a signal indicative of a rotation angle of the monitoring roller. A control unit ( 40 ) collects, during a calibration phase, the signal from the encoders over multiple rotations of the monitoring rollers, detects a deviation of the signal from the encoder relative to a clock signal having a predefined frequency, and computes runout correction factors. During an operational phase, the control unit applies the runout correction factors to synchronize the droplets ejection from the print bars.