Claims:WE CLAIM:

1. A full repeat print monitoring system to obtain the image of the entire width of a substrate on a single repeat comprises of:
a substrate positioned over a web transport roller;
a first encoder mounted proximate to start position of the web transport roller;
a camlink frame grabber card connected to a computing device, wherein the camlink frame grabber is positioned behind the first encoder;
a plurality of high resolution line scan camera positioned between the first encoder and the camlink;
a second encoder mounted on the machine that is at 1:1 ratio to a print cylinder;
a front light arrangement mounted at an angle, positioned on the top of the substrate at a specific distance and connected to the LED controller on a computing device; and
a back-light arrangement mounted below the substrate at a specific distance and connected to a power source of the computing device; wherein the back-light arrangement is perpendicular or at an angle to the line scan camera, and in an offset position to the front light arrangement;
characterized wherein in that the full image is viewed on the large monitor display, and on a smaller monitor display showing an image of 1:1 pixelate image.

2. The full repeat print monitoring system as claimed in claim 1, wherein the first encoder acts as an input trigger that triggers high resolution line scan camera to scan image line by line at any speed.

3. The full repeat print monitoring system as claimed in claim 1, wherein repeat and start/stop is sensed by first encoder mounted on the machine.
4. The full repeat print monitoring system as claimed in claim 1, wherein full image is viewed on 55’ monitor.

5. The full repeat print monitoring system as claimed in claim 1, wherein smaller image is viewed on 22’’ monitor.

6. The full repeat print monitoring system as claimed in claim 1, wherein icon based graphical user interface is incorporated for operating print monitoring.

7. A method of operating a full repeat print monitoring system comprises the steps of:
allowing the substrate to move over the web transport roller from the start position;
illuminating the substrate with the help of front light and back light arrangement;
encoding the movement of the substrate with the help of first encoder;
sending the input trigger received from the first encoder to high-resolution line scan camera;
scanning the image of the substrate line-by-line with the help of line scan camera;
capturing the image of the entire width of the substrate of a single repeat by using the camlink frame grabber card, that is connected to the PC;
encoding repeat and start/stop of the substrate with the help of a second encoder mounted on the machine;
acquiring full image on 55’ monitor; and
pixelating the image in the ratio of 1:1 with the help of 22’ monitor.

8. The method of operating a full repeat print monitoring system as claimed in claim 7, wherein, on receipt of "0” signal is generated on completion of full print repeat once the substrate is scanned.

9. The method of operating a full repeat print monitoring system as claimed in claim 7, wherein, on receipt of '0' signal, the camera generates a frame and transfers frame data to PC.

10. The LED light arrangement used as front light and back light comprises of:
-metallic reflector plates/cavity, wherein strips of plurality of LED bulbs are arranged horizontally, inside the metallic reflector plate/cavity;
-said metallic reflector plates/cavity are mounted on the printing machine such that the light emitted by the LED bulbs reflects on the metallic plate/cavity; and
-said metallic plate /cavity in turn reflect the substrate to be scanned when mounted on the printing machine.

11. The LED light arrangement as claimed in claim 10, optionally may also comprise of arrangement with variable intensity to view different substrate.

, Description:TECHNICAL FIELD

[0001] The present invention relates to a print monitoring system and method of operating the same. More particularly the invention relates to full repeat print monitoring system, so as to view stationary image of the entire single repeat of the substrate and method of operating the same thereof.

BACKGROUND

[0002] Printing and packaging industry has become competitive with ever escalating demands for improved print quality, reduced wastage, etc., hence highly precise substrate viewing is a critical requirement for packaging printers. On the printing machine, an operator needs to view the substrate constantly, while printing is going on so as to check the quality of printing. At higher substrate speed, it becomes difficult to examine running substrate by unaided human eye. Web video system allows the operator to view stationary image of the printing material at high speeds and magnification features helps an operator to inspect minutely at the print quality.

[0003] Generally, partial viewing systems are available for viewing print on flexible printing machines like rotogravure, flexo and offset printing machines. For example, if print width is 1200 mm and repeat is 500 mm, then with current available systems, the operator can see only part of the printed material (substrate), e.g. 150 mm x 100 mm of area, using area scan cameras. Hence, to view the full print area, the operator has to move the camera across the substrate to observe all print areas. It is obvious that given the viewing area (e.g. 150 mm x 100 mm), the operator can never observe 100% of the print. Further, 100% substrate viewing system is not possible with area scan camera. Major hindrances are distance between substrate and camera greater than 1000 mm, image resolution (pixel size) and homogenous illumination for the full print area (eg.1200 mm x 500 mm).

[0004] At present the only product available to monitor full substrate width is Stroboscope. But the constant flickering of Stroboscope lights makes it strenuous for operator’s eyes. Therefore, in order to overcome this limitation and view the entire width of the substrate at any given time, there is a need for providing a print monitoring system that operates with the help of line scan camera to aid operator to view stationary image of the entire width of the substrates, so that the operator can instantly take corrective measures to reduce wastage of print material.

SUMMARY
[0005] The main aspect of the present disclosure, relates to a full repeat print monitoring system, wherein a line scan camera is used to capture full print repeat of a substrate being printed at high speeds up to 450meters/min. The captured data from the line scan camera is processed to form an image, using algorithms and computing device. The image thus produced, is shown on a large first monitor, such that print defects can be observed by the naked eye. Likewise, a smaller second monitor is attached to the system. Said second monitor is used for magnifying the areas of interest from the full repeat. Besides, the small monitor also displays other features like split screen for monitoring ‘traffic lights’ and other register marks printed on either side of the substrate.

[0006] Another aspect of the present invention, relates to method of operating the full repeat print monitoring system.

OBJECT OF THE PRESENT INVENTION
[0007] The object of the present invention is to provide a full repeat print monitoring system.
[0008] Another object of the invention is to provide a stationary view of the entire width of the substrate.
[0009] Yet another object of the present invention is to provide a full repeat monitoring system to reduce wastage of print material.
[0010] Yet another object of the present invention is to provide a method of operating full repeat print monitoring system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The detailed description is described with reference to the accompanying figures.

[0012] Figure 1, is a schematics representation of the primary positioning of the line scan camera, front light arrangement and back light arrangement.

[0013] Figure 2, is a schematic representation of the assembly of the full repeat print monitoring system.

[0014] Figure 3, illustrates positioning of the components in full repeat print monitoring system.

[0015] Figure 4, illustrates a flow chart of method of operating full repeat print monitoring system.

[0016] Figure 5, illustrates a block diagram indicating positions of the components in full repeat print monitoring system for viewing the full repeat of a substrate.

[0017] Figure 6, is a schematic representation of the positioning of the LED mounted reflector plates/cavity.

DETAILED DESCRIPTION

[0018] The present invention uses a line scan camera to capture full print repeat of a substrate being printed at high speeds up to 450 meters/min. The captured data from the line scan camera is processed to form an image, using algorithms loaded on a computer or on a computing device. The image thus produced, is displayed on a large monitor, such that print defects can be observed by the naked eye, similarly a smaller second monitor is attached to the system. Said second monitor is used for magnifying areas of interest from the full repeat. Besides, the small monitor also displays other features like split screen for monitoring ‘traffic lights’ and other register marks printed on either side of the substrate.

[0019] The full repeat print monitoring system as disclosed in the present invention aids an operator to view an image that appears to be stationary or is stationary of the entire width of the substrate. By looking at this image, an operator can instantly take corrective action to reduce print material wastage. Full repeat print monitoring system works with line scan camera and LED mounted reflector plates, that thereby showing the full repeat view on the big screen.

[0020] Referring to Fig.1 illustrate schematic representation of the primary positioning of the line scan camera, front light arrangement and back light arrangement, wherein the substrate to be printed are allowed to move at high speed. The line scan camera is mounted at a specific distance from the substrate) so as to capture the entire width of the substrate. Therefore, for every full print repeat of the substrate a “0” signal is generated that is given as an input to full repeat monitoring system., On receipt of '0' signal, the camera generates a frame and transfers frame data to PC. The front light is mounted at a desired angle and at a specific distance from the substrate so as to illuminate the printing material. The back light is mounted just below the moving substrate. Further the line scan camera mounted at the top and the back light mounted below the substrate are either perpendicular to each other or at angle and are mounted opposite to each other, whereas the front light is mounted at the top at a specific distance from the moving substrate, and the back light mounted below the moving substrate are positioned off-set to each other.

[0021] Fig. 2 and Fig. 3 illustrates assembly and positioning of the components for full repeat monitoring system. Initially, the substrate is allowed to move over the web transport roller on which the encoder is mounted, said encoder mounted on web transport roller, acts as an input trigger that senses the movement and speed of the substrate and triggers the High-resolution line scan camera to scan the image line by line at any print speeds. Said high-resolution line scan camera is connected to the Camlink frame grabber card that in turn is connected to PC to obtain the desired/full image frame of a single repeat. Repeat and start/stop is sensed by another encoder mounted on the machine which is at 1:1 ratio to print cylinder (repeat). The acquired full image is shown on 55” monitor, and on 22” monitor part of the 1:1 pixelate image is shown. Since encoder pulse of the print cylinder repeat is random and not necessarily occurring at the beginning of print repeat, further additional functions where operator can select the start position of the repeat in acquired images and set the start of print repeat display is also enabled. Further simultaneously, to view the printing on polyester film, front light arrangement and back light arrangement are mounted offset to each other in opposite direction to illuminate the substrate to be scanned for homogeneous illumination. Said front light and backlight is connected to the LED illumination controller. Once the substrate to be scanned completes full print repeat, ‘0’ signal is generated, that is given as an input to full repeat monitoring system. On receipt of '0' signal, the camera generates a frame and transfers frame data to PC. The PC shows images and further image processing functions can be applied as per user's requirements. Icon based Graphical user interface (GUI) makes it easy for the operator in print monitoring.

[0022] The front light arrangement and back light arrangement disclosed in the present invention, optionally may be built such that they can provide variable intensity depending on the nature of the substrate to be scanned. The monitoring system can be built, such that it may have plurality of cameras based on the resolution requirement, working distance and desired budget.

[0023] Fig. 4 illustrates a flow chart of method of operating full repeat print monitoring system. The substrate to be scanned is first allowed to move over a web transport roller on which the encoder is mounted, said encoder sends an input trigger signal to the high resolution line scan camera to scan the substrate line by line at high print speeds. After completing full print repeat ‘0’ signal is generated, that is given as an input to full repeat monitoring system.. On receipt of '0' signal, the camera generates a frame and transfers frame data to PC. The PC shows images and further image processing functions can be applied as per user's requirements. Icon based Graphical user interface (GUI) makes it easy for the operator in print monitoring, wherein the graphical image obtained may be digitally zoomed, may be rotated, or split, flipped vertically, flipped horizontally. Further the user can also select the region of interest and have the option of selecting the image start position.

[0024] Figure 5, illustrates a block diagram indicating positions of the components in full repeat monitoring system for viewing the full repeat of a substrate. The substrate to be scanned is first allowed to move over a web transport roller, wherein the encoder sends an input trigger signal to the high-resolution line scan camera to scan the substrate line by line at high print speeds. After completing full print repeat ‘0’ signal is generated by the full repeat monitoring system. On receipt of '0' signal, the camera generates a frame and transfers frame data to PC. The PC shows images and further image processing functions can be applied as per user's requirements. The acquired full image is shown on 55” monitor, and on 22” monitor part of the 1:1 pixelate image is shown. Icon based Graphical user interface (GUI) makes it easy for the operator in print monitoring, wherein the graphical image obtained may be digitally zoomed, may be rotated, split, flipped vertically, flipped horizontally. Further the user can also select the region of interest and have the option of selecting the image start position. Front light arrangement and back light arrangement are mounted offset to each other in opposite direction to illuminate the substrate to be scanned for homogeneous illumination. Said front light and backlight is connected to the LED illumination controllers,

[0025] Fig. 6, is a schematic representation of the positioning of the LED mounted reflector plates/cavity, wherein strips of plurality of LED bulbs, are arranged horizontally, inside the metallic reflector plate/cavity, such that the light emitted by the LED bulbs reflects on the metallic plate/cavity. The metallic plate/cavity in turn reflect the substrate to be scanned when mounted on the printing machine. The front light arrangement is mounted at an angle, such that it is positioned offset from the back-light arrangement. The back-light arrangement is exactly perpendicular or at an angle to the line scan camera. Optionally, to view the printing on polyester film, backlight and front light arrangement required with variable intensity to view different substrates can also built based on the illumination requirement and working distance.

[0026] The present invention discloses a print monitoring system and method that plays a major role in providing superior print quality. In partial viewing systems, it is likely that defects may be noted by the operator, after several printed substrates has been produced, thereby resulting in wastage of print substrate. This is solved in the present invention by providing a full repeat viewing system, since the full print format may be viewed on 55” monitor, and since the operator is viewing the full print, defects can be observed as soon as they occur and early action can help prevent wastage. Further the 22” monitor is used for magnifying areas of interest from the full repeat. Besides, the small monitor also displays other features like split screen for monitoring ‘traffic lights’ and other register marks printed on either side of the substrate.

[0027] The present invention provides the technical and commercial advantages by providing a process for viewing the full print repeat at a single go, better process control since the operator can select the start position of the repeat in acquired images and set the start of print repeat display, reducing wastage of substrate by looking at the image generated on the monitor and instantly taking corrective action for minimal wastage and may be scaled up to a 100% print inspection system, thereby allowing the buyer to invest in two phases. The two-step implementation helps operators to learn about the defects and once they are familiar, upgrade to sophisticated 100% print inspection system.

[0028] The above description along with the accompanying drawings is intended to describe the preferred embodiments of the invention in sufficient detail to enable those skilled in the art to practice the invention. The above description is intended to be illustrative and should not be interpreted as limiting the scope of the invention. Those skilled in the art to which the invention relates will appreciate that many variations of the described example implementations and other implementations exist within the scope of the claimed invention.