Method of and apparatus for printing on a web

Abstract

Method and means of printing on a web. The method means comprise in a normal mode: feeding the web in a machine direction; printing on the web with a printer; and drying or curing the printing with a dryer or curer located downstream, with respect to the machine direction, of the printer; and in a pause mode: pausing printing on the web; feeding the web in the machine direction while printing on the web is paused by a distance such that a portion of the web located between the printer and the dryer or curer, the portion having printing thereon that has not yet been cured or dried, is fed through the dryer or curer to dry or cure the printing; and thereafter pausing feeding of the web in the machine direction.

Claims

1. A method of printing on a web, the method having at least a normal mode and a pause mode that are implemented at least in part by a controller and the method comprising: in the normal mode: feeding the web in a machine direction with a feeder; printing on the web with a printer; and drying or curing the printing with a dryer or curer located, with respect to the machine direction, downstream of the printer; and in the pause mode: pausing the printing on the web; feeding, while the printing on the web is paused, the web in the machine direction by a distance such that a portion of the web located between the printer and the dryer or curer when the printing on the web is paused, is fed through the dryer or curer; and after the portion of web located between the printer and the dryer or curer when the printing on the web was pause has been fed through the dryer or curer, pausing feeding of the web in the machine direction.

2. The method of claim 1, wherein the portion of the web located between the printer and the dryer or curer when the printing on the web is paused has printing that has not yet been cured or dried, and when the portion of the web is fed through the dryer or curer, the printing on the portion is dried or cured.

3. The method of claim 1, wherein the feeding the web in the machine direction in the normal mode is carried out at a same speed or at a lower speed than in the pause mode.

4. The method of claim 1, wherein the web is to be partitioned into regular sized portions representing continuously repeating locations at which printing is to be applied and the method comprises printing with the printer on each regular sized portion as the web is fed in the machine direction in the normal mode.

5. The method of claim 4, wherein the method comprises printing discrete data items, such as codes, with one or more data items printed on each regular sized portion.

6. The method of claim 1, wherein the method further has a resume mode implemented at least in part by the controller to exit the pause mode and re-enter the normal mode, and the method further comprises, in the resume mode: moving the web counter to the machine direction so that an unprinted portion of the web located between the printer and the dryer or curer after the feeding was paused in the pause mode is positioned, relative to the machine direction, upstream of the printer; and re-entering the normal mode so that the unprinted portion of the web is printed on with the printer and dried or cured by the dryer or curer as the web is fed in the machine direction.

7. The method of claim 6, wherein the method further comprises: in the normal mode, printing on the web at regularly sized continuously repeating portions of the web, wherein, in preparing for re-entering the normal mode, the resume mode moves the web counter to the machine direction so that the first printed web portion upon re-entering into the normal mode is adjacent the last one of the regularly sized continuously repeating portions that was printed before the previous normal mode was exited.

8. The method of claim 1, wherein the method comprises detecting areas of the web with a position sensor located upstream of the printer and triggering printing on the web in the normal running mode based on the detected areas.

9. The method of claim 1, wherein the printing is in the form of readable printed data, and the method further comprises reading each item of readable printed data with a quality control reader, and wherein the readable printed data is able to be checked for readability and/or is able to be uploaded to a product tracing system.

10. The method of claim 1, further comprising: in the normal mode, feeding the web through a web storage part defining an adjustable web feed path length to maintain a web feed path length that is fixed; and in the pause mode, feeding the web from the web storage part while reducing the length of the web feed path through the web storage part.

11. The method of claim 1, wherein the method comprises feeding the web in the machine direction during both the normal mode and the pause mode via a driver.

12. The method of claim 6, the method further comprising: in the normal mode, feeding the web through a web storage part defining an adjustable web feed path length; and in the resume mode, moving the web counter to the machine direction while increasing the length of the web feed path length in the web storage part.

13. The method of claim 1, wherein the method further comprises, in the normal mode: feeding the web from a source reel through the printer and the dryer or curer; and winding the web about a target reel.

14. An apparatus for printing on a web, the apparatus comprising: a feeder for feeding the web in a machine direction; a printer for printing on the web; a dryer or curer located, with respect to the machine direction, downstream of the printer to dry or cure the printing on the web; and a controller configured to implement: a normal mode of operation in which the web is fed in the machine direction, the web is printed on with the printer, and the printing is dried or cured with the dryer or curer; and a pause mode of operation in which printing of the web by the printer is paused while feeding of the web in the machine direction by the feeder continues so that a portion of the web located between the printer and the dryer at a start of the pause mode is fed through the dryer or curer to dry or cure the printing, whereupon the feeding of the web in the machine direction is paused.

15. The apparatus of claim 14, wherein the portion of the web located between the printer and the dryer or curer when the printing on the web is paused has printing that has not yet been cured or dried, and when the feeder feeds the portion of the web through the dryer or curer, the printing on the portion is dried or cured.

16. The apparatus of claim 14, wherein the controller is configured to feed the web in the machine direction in the normal mode at a same speed or at a lower speed than in the pause mode.

17. The apparatus of claim 14, wherein the web is to be partitioned into regular sized portions and the controller is configured to control the printer to print on the regular sized portions as the web is fed in the machine direction in the normal mode.

18. The apparatus of claim 14, wherein the controller is configured to control the printer to print discrete data items, such as codes, with one or more data items printed on each portion of the web.

19. The apparatus of claim 14, wherein the controller is further configured to: implement a resume mode of operation, after exiting the pause mode and before re-entering the normal mode, in which the web is moved counter to the machine direction so that an unprinted portion of the web located between the printer and the dryer or curer after the pause mode is positioned, relative to the machine direction, upstream of the printer, and to subsequently re-enter the normal mode of operation in which the printer prints on the unprinted portion of the web and the dryer or curer dries the printing as the web is fed in the machine direction.

20. The apparatus of claim 19, wherein the control system is further configured to: implement in the normal mode of operation printing at regularly sized continuously repeating portions of the web along the machine direction of the web, and to re-enter the normal mode after the pause mode by controlling the printer to commence printing on a one of the regularly sized continuously repeating portions that is located upstream of the regularly sized continuously repeating portion that was last printed on during the previously implemented normal mode in order to continue the sequence of printing on each regularly sized continuously repeating portion.

21. The apparatus of claim 14, further comprising a position sensor located upstream of the printer for detecting areas of the web that are regularly spaced in the machine direction throughout the web, and the control system is configured to implement the normal mode by triggering the printer to print on each portion of the web based on the detection of the areas by the position sensor.

22. The apparatus of claim 14, further comprising a quality control reader located downstream of the printer and the dryer, wherein the quality control reader is configured to read the printing on the web, which is in the form of printed readable data, wherein the controller is configured to process the read printed data to check for readability and/or is configured to output the read data to a product tracing or tracking system.

23. The apparatus of claim 14, further comprising a driver that is rotatable to feed the web in the machine direction and a web storage part that defines an adjustable web feed path, wherein controller is configured so that, in the normal mode, the web is fed through the web storage part using the driver, thereby maintaining a fixed web feed path, and so that, in the pause mode, the printer is paused and the web is fed out of the web storage part in the machine direction using the driver by at least a distance corresponding to a distance between the printer and the dryer or curer, which thereby reduces the web feed path length.

24. The apparatus of claim 19, further comprising: a web storage part defining an adjustable web feed path in the normal mode, and a driver that is rotatable to feed the web in the machine direction and in the counter machine direction, wherein the controller is configured to feed the web, in the normal mode, in the machine direction by driving rotation of the driver, and the controller is configured to allow, in the resume mode, the driver to reverse rotation while increasing the feed path through the web storage part to move the web counter to the machine direction.

25. The apparatus of claim 14, further comprising: a source reel; and a target reel, wherein the controller is configured to unwind the web from the source reel and to wind the web around the target reel in feeding the web in the machine direction during the normal mode of operation.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a reel to reel printing apparatus according to an embodiment of the present invention;

(2) FIG. 2 shows a functional diagram of a control system of the present invention;

(3) FIGS. 3 to 5 illustrate a web printing scheme that includes a pause mode introducing improperly printed data as a result of the pause mode.

(4) FIG. 6 shows printing on a web according to an embodiment of the present invention;

(5) FIG. 7 shows a pause mode in which the printer is paused, but the web is allowed to continue running for a short distance after printing is paused;

(6) FIG. 8 shows web movement upon entry into a resume mode; and

(7) FIG. 9 shows a normal running mode after the resume mode in which the web is running forward, is printed on and dried or cured.

DETAILED DESCRIPTION

(8) To summarise features of the present invention, a printing operation is performed on a web at a printer. The web with printing thereon travels to a dryer or curer at which the printing is dried or cured. In a pause mode, movement of the web is to be paused. In order to avoid that the printing on the part of the web between the printer and the dryer or curer is spoiled while movement of the web is paused, the web is fed in the machine direction in the pause mode for a length of web from the printer to the dryer or curer while the printer is in a paused state and thereafter the web movement is paused.

(9) In an embodiment, a portion of web that has not been printed on by the printer as a result of the paused state of the printer extends between the printer and the dryer or curer.

(10) In an embodiment, in a resume mode for the transition from the pause mode back to a normal running mode, the web is moved back so that the portion of the web that not been printed on is positioned at or upstream of the printer. Subsequently, in the normal running mode, the web resumes moving forward, while the printer resumes the printing operation to print on the web. The printing is restarted so that the portion of the web that has not been printed on, and which portion was moved upstream of the printer in the resume mode, is subjected to the printing operation.

(11) In an embodiment of the pause mode, the web is moved forward while the printing operation is paused by driving the web forward releasing stored web held in a tensioner.

(12) In an embodiment of the resume mode, the web is moved backward by operating tensioner to store more web therein.

(13) In an embodiment, blank web is unwound from a source reel and printed web is wound on a target reel. In the present application, the term blank web does not necessarily mean that the web has no printing on it. This term instead refers to a web that has not yet been printed on at the printer.

(14) In an embodiment, the printing comprises printing tax stamps or labels or printing on product packaging, labels or stamps. The printing can involve printing alphanumeric characters and/or printing codes.

(15) The printing may include one or more security features, such as covert features. In particular, the printing ink may luminesce with a distinctive material signature.

(16) Referring to FIG. 1, an unprinted web is unwound from a source reel, is passed through a printing unit and is wound on a target reel. The apparatus includes a web tensioning mechanism including guide rollers and a tension arm. Before passing through the printing unit, the web passes one or more sensors for sensing portions of the web to be printed on. This sensing is used to trigger the printing unit to print data on each portion. The apparatus also includes a quality control unit for reading data printed on the web by the printing unit. In FIG. 1, there is shown an apparatus 20 for printing codes on a web 12 of, e.g., product labels. The present embodiment is disclosed particularly with reference to printing codes for product labels or stamps, but the teachings of the present application are more generally applicable to printing information on a web of material.

(17) The apparatus comprises a source chuck or reel 1 on which a blank stock web 2 is wound. The source chuck 1 serves to act as a source of web material 12 that is to be passed through the printing apparatus 20 so that codes or other information can be printed on the web 12. The source chuck 1 is rotatable to supply web 12 into the printing apparatus 20. A brake is associated with the source chuck 1 to apply tension to the web 12 unwinding from the source chuck 1.

(18) The blank web 2 on the source reel 1 may be paper based web or other sheet-like flexible material that can be printed on. The blank web 2 is divisible into individual stamps or labels once printed on. For example, the web can be described as forming one or more labels or stamps in the cross machine direction and being divisible into separate labels or stamps at regular intervals in the machine direction. The blank web 2 may pre-include security features thereon associated with each label or stamp to be formed. For example, the security features may include watermarks, intaglio printing, etc.

(19) The apparatus 20 also includes a printing unit 7 for printing codes on web 12 that has been unwound from the source chuck 1. The printing unit applies a code to each area of the web 12 for forming a stamp or label. The code facilitates the tracing of a product associated with the label or stamp throughout the supply chain from a manufacturing plant, and through a distribution hierarchy. The codes, when implemented on labels, stamps or packaging of duty excisable products, are able to be scanned helping government inspectors to ensure that taxes are properly paid.

(20) The printing unit 7 may print the codes using security inks and may also print one or more further security features. For example, the printed codes may include covert security features that are identifiable by a special hand held device able to determine material properties of the ink.

(21) The printing unit 7 includes a printer for printing the codes using ink that may be ultraviolet curable. The printing unit 7 may include more than one printer. The printing unit 7 may be a drop on demand printer such as an inkjet printer.

(22) The printing unit 7 includes a curer or dryer, as discussed further below, spaced downstream from the printer of the printing unit 7. The downstream spacing prevents unwanted interference between the printer and the dryer or curer.

(23) The apparatus 20 includes a target reel or chuck 11 on which the web 12 is wound into a winding of coded stamps or labels 10 (or material for forming product packaging) after having been printed with codes by the printing unit 7. The target reel 11 is associated with a driver that sets a machine direction speed of the web 12 passing through the apparatus 20 from the source reel 1 to the target reel 11. The driver may include a motor and a transmission.

(24) The apparatus 20 includes a quality control unit 8 that is configured to read the printed information, e.g. product trace codes and/or tax codes. The quality control unit 8 is controlled to send the read information to a main application to track the information/codes printed and read as well as determine any errors or illegibility in the printed information.

(25) In one implementation, the quality control unit 8 includes a camera for reading the printed information and a processor for interpreting the read information. The quality control unit 8 may also include a light source that is tailored to the ink or other material used for printing the information so that covert material based features associated with the ink can be read. For example, the ink may luminesce, e.g. fluoresce, in a way that is characteristic of the ink used and in a way that is determinable under certain lighting conditions. The quality control unit 7 may be configured to check a luminescence signature of the printed information as well as to allow checking and tracking of the information itself.

(26) The apparatus 20 includes guide rollers 4 and a tension arm 3 having a tension roller 13 at an end of the tension arm 3. The tension arm applies a tensioning force on the web 12 by contact through the tension roller 13. The tension roller 13 contacts the web 12 at a location between (in the machine direction) the guide rollers 4. The tension arm 3 is operable to apply greater or lesser tension to the web 12. The tension arm 3 moves to allow web 12 to move forward during the pause mode of the apparatus 20 and moves in an opposite direction to reverse the web 12 during the resume mode, as is discussed further below.

(27) The tension arm 3 is able to apply a constant tension to the web 12 by applying a force in the direction away from guide rollers 4 adjacent in the upstream and downstream direction. The tension on the web 12 applied by the tension arm 3 may be caused by a weight of the tension arm 3 acting through the web 12 and/or by pneumatic pressure acting to cause the tension arm 3 to apply tension to the web 12.

(28) The web 12 includes markers associated with each portion of the web 12 that is to be printed on at the printing unit 7. In such an embodiment, the apparatus 20 includes one or more sensors 6 for detecting the markers. The markers can be dedicated contrast markings that are detectable by an appropriate sensor. Alternatively, the markers may be part of the web 12, such as perforation lines, or the markers may be a designated part of pre-printing on the web 12.

(29) The markers are sensed by the one or more sensors 6, resulting in sensor producing a sense signal. The sense signal is used by a control system for timing printing on each portion of the web 12 by the printing unit 7. A plurality of sensors 6 can be provided in the apparatus 20 so that the printing apparatus 20 is operable with different types of webs 12, specifically those with dedicated contrast markers and those without such.

(30) The apparatus 20 includes an alignment unit 5 to ensure the web 12 remains in the correct position in the cross-machine direction. This makes sure that the web is correctly positioned for downstream sensing with the one or more sensors 6, printing with the printing unit 7 and for quality control with the quality control unit 8.

(31) The apparatus 20 further comprises an ejection unit 9 that allows printed parts on the web 12 that have been rejected by the quality control unit 8 to be ejected from the web 12 before being wound on the target reel 11. Further disclosure concerning an ejection unit 9 can be found from WO 2011/051396 A1.

(32) FIG. 2 shows a control system including an arm tension module for controlling web tension and also for implementing forward movement of the web during a pause mode and for implementing backward movement of the web during a resume mode. The control system includes a main controller that receives feedback from sensors to control web tension, web speed, timing of the printing unit and timing of the quality control unit. Further, FIG. 2 functionally illustrates a control system 30 used for controlling the apparatus 20 of the present invention. The control system 30 includes a controller 31 in communication with all modules in the control system 30 apart from the alignment module 32. The controller 31 is configured to receive output signals from the various modules, process the signals and output control command signals.

(33) The controller 31 can be implemented using a processor and suitably programmed software. The controller 31 is configured to instruct various control modules to implement a normal running mode, a pause mode and a resume mode. These modes will be described in further detail below.

(34) The control system 30 includes a brake reel control module 33 that is operable on a brake associated with the source reel 1. The strength of the brake is adjustable by the brake reel control module 33 in order to adjust tension on the web 12. The brake reel control module 33 is further operable to lock the source reel 1 from rotating, which is used in a paused mode of the apparatus 20 and control system 30 as will be described below. The controller 31 communicates with the brake reel control module 33 to set the strength of the brake acting on the source reel 1.

(35) The control system 30 includes a tension module 34 that operates with a web tension sensor to determine tension on the web 12 as a sensed input for the controller 31. The web tension sensor may use compressed air to deflect the web 12 and to determine tension in the web 12 from the deflection. An output signal representative of web tension is sent to the controller 31. The controller uses this information and implements a feedback loop in communication with the brake reel module 33 to set the strength of the brake appropriately to ensure tension in the web 12 is as desired, e.g. within control limits.

(36) The control system 30 includes an engine reel module 50. The engine reel module 50 operates in communication with a motor for driving the target reel 11. The engine reel module 50 is responsible, in association with the controller 31, for controlling speed of the web 12 through the printing apparatus 20.

(37) The control system 30 includes a web speed module 37 that communicates with a web speed sensor in order to determine the machine directional speed of the web 12. The web speed sensor may be implemented by a wheel in contact with the web 12 and thus having a detectable rotational speed indicative of the speed of the web 12. The web speed module 37 is configured to determine the web speed from an output of the web speed sensor and to communicate the web speed with the controller 31.

(38) The controller 31 is configured to receive an output signal from the web speed module 37 to implement a feedback loop in association with the engine reel module 50 to set the speed of the web 12 as desired, for example within control limits.

(39) The control system 30 includes a printer module 38 that communicates with the printing unit 7 to print data on the web 12. In particular, the printer module 38 is effective to cause a printer of the printing unit 7 to print a code on each portion of the web 12. The codes may represent tracking data, such as product ID, production facility, date, time and optionally also tax data. The printer module 38 is responsive to a print signal from the controller 31 to instruct the printing unit 7 to print the data on the web 12.

(40) The control system 30 includes at least one sensor module 35, 36 working with the one or more sensors 6 for determining a position of each portion of the web 12 to be printed on. For example, the sensor module may be operable to detect the position of each label or stamp sized, predetermined, portion of the web 12. The at least one sensor module 35, 36 is configured to output a signal indicating machine direction position of the web portion to the controller 31. Based on the position information, the controller times a print command signal to the printer module 38 to print data at the correct position on the web 12.

(41) The at least one sensor module may include a contrast position module 35 working with a contrast sensor 6 for detecting a position of each predetermined portion in the web 12 by sensing contrast markings located at predetermined positions in each portion. Additionally or alternatively, the at least one sensor module may include an optical sensor module 36 that operates with an optical sensor 6 for determining optical characteristics located at a predetermined position of each portion of the web 12. In conjunction with an output from the at least one sensor module 35, 36 for determining a position of each portion in the web 12, the controller is able to command the printer module 38 to instruct the printing unit 7 to print data in each portion of the web 12 at the correct location.

(42) The web portions described herein represent portions of the web 12 that are to be printed on. Generally, the web portions are of equal size and are positioned one after the other in a repeating sequence through the web 12. The web portions may correspond to individual labels, stamps or product packaging to be formed from the web 12.

(43) The control system 30 includes a quality control module 39 that works with a camera of the quality control unit 8 to read data printed on the web 12 by the printing unit 7 and send this data to the controller 31 as an output. The quality control module 39 may be configured to operate a light source and optionally may include an optical filter to successfully read the printed data. The quality control module 39 works under instruction from the controller 31. The controller 31 is configured to trigger operation of the quality control module 39 to read the printed data at a time determined by the controller 31 that coincides with the printed data arriving at the quality control unit 8. The controller 31 is configured to determine the proper timing based on position information received from an output from the at least one sensor module 35, 36. The controller 31 is configured to send a signal representative of the printed data, as output from the quality control module 39, to a main application for product tracking and optionally also tax duty accounting purposes.

(44) The control system 30 includes an alignment module 32 that operates with at least one sensor for detecting a cross-directional position of the web 12. The alignment module 32 operates autonomously. The alignment module 32 uses the sensed cross directional web position in determining an output signal for controlling a web position adjuster to correct cross-directional positioning of the web 12.

(45) The control system 30 includes an interlock module 43 configured to ensure a door to the apparatus 20 is locked for personnel safety reasons. The interlock module 43 is configured to only allow the door to be unlocked when the source reel 1 and the target reel 11 are not rotating. The interlock module 43 is in communication with the controller 31 to output an interlock signal representative of the locked or unlocked state and to receive an output from the controller 31 representative of the moving status of the reels 1, 11.

(46) The control system 30 includes an emergency stop module 42 that operates with an emergency stop button for the apparatus 20. The emergency stop module 42 is configured to communicate with the controller 31 when the emergency stop button has been activated to issue an output command for stopping the source reel 1 using the brake reel control module and/or for stopping the drive reel 11 using the engine reel control module 50.

(47) In the normal running mode, the controller 31 is configured to instruct the engine reel module 40 to transport the web 12 at a predetermined speed based on a sensed speed of the web 12 from the web speed module 37. The target reel 11 is rotated under command from the engine reel control module 50 to transport the web 12 from the source reel 1 through guide rollers of the printing apparatus 20 to be wound on the target reel 11.

(48) In the normal running mode, the controller 31 checks tension on the web 12 through the arm tension module 34 and instructs the brake reel module 33 appropriately to adjust the brake associated with the source reel 1 to adjust the web tension.

(49) In the normal running mode, the controller 31 receives machine direction position information from the one or more sensor modules 35, 36 and triggers printing of data at each predetermined portion of the web 12 by issuing an appropriately timed trigger signal to the printer control module 38. In the normal running mode, the controller 31 also issues an appropriately timed signal to trigger the quality control module 39 to read the printed data at each portion of the web 12 based on the machine direction position information.

(50) There are occasions in operation of the apparatus 20 when a pause mode is required when movement of the web 12 is to be paused. After the pause mode, according to the present invention, the apparatus enters a resume mode before the normal running mode is resumed. According to the present teachings, it is important that such a pause mode and such a resume mode does not cause wastage of the web 12 and/or spoiling of the printed data. The manner by which web wastage and printed data spoilage can occur is described below with reference to FIGS. 3 to 5 and the manner by which the present invention avoids such costly problems is described with reference to FIGS. 6 to 9.

(51) Referring to FIG. 3, an interaction can be seen between the web 12, the printer 40 and the dryer or curer 41 of the printing unit 7 and the quality control unit 8. The web 12 is divided into predetermined portions 42 each representing an area of the web 12 for receiving printed data T from the printer 40. The predetermined portions 42 may be real in the sense of the web having pre-printing thereon designating each portion 42 or they may be virtual portions 42, in which case contrast markers may be associated with each web portion 42. The predetermined portions 42 may form labels or stamps, particularly for items subject to tax duty.

(52) Before the printer 40, the portions 42 are blank or unprinted in the sense of the data not yet having been printed on the web 12. In the uncured or undried portion of web 12, extending between the printer 40 and the dryer or curer 41, the data T has been printed on the web 12 in each portion 42, but the printed data T is not yet dried or cured.

(53) After the dryer or curer 41, the printed data T in each portion 42 is dried or cured. The quality control unit 8 is configured to read the dried or cured printed data T to check readability as well as to output the read data for use in a tracking system and/or a tax duty accounting system.

(54) In a pause mode shown in FIG. 4, the web 12 is stopped and so does not move in the machine direction. In this paused mode, the printed data T in the portion of the web extending between the printer 40 and the dryer 41 will not be cured or dried in sufficient time. This tends to spoil the printed data T as a result of, for example, bleeding of the ink when liquid ink is used. Other types of ink or printing media will also lead to corrupted printing if not cured within an allotted time.

(55) Accordingly, the printed data in each of the portions 42 of the web 12 in the stretch between the printer 40 and the dryer or curer 41 will likely not be readable by the quality control unit 8. The quality control unit 8 will flag these printed portions as rejected and they will have to be removed from the batch by way of the ejection unit, which is time consuming, difficult and costly in terms of materials (e.g. the web 12 and the print media).

(56) FIG. 5 shows the printed web 12 with movement of the web 12 resumed and with the apparatus 20 and the control system 30 in normal running mode. The printed web 12 has a length in the machine direction of five portions 44 with improperly cured or dried data thereon that are each rejected by the quality control unit 8.

(57) In view of the above issues explained with reference to FIGS. 3 to 5, the system and method of the present invention implements pause and resume modes that can reduce or avoid any improperly cured or dried printed data and also reduce or avoid wastage of the web 12. These improvements are explained with reference to FIGS. 6 to 9.

(58) FIG. 6 shows a normal running mode in which the web is printed on at regular intervals by a printer. The printed web moves to a printing dryer or curer positioned downstream of the printer at which the printing is dried or cured. The printing on the dried or cured web is checked at a quality control unit. In particular, FIG. 6 shows a longitudinal segment of the web 12 travelling in the machine direction (as indicated by the arrow) in the normal running mode. It can be seen that the one or more sensors 6, the printer 40, the dryer or curer 41 and the quality control unit 8 are positioned in this order along the downstream direction. The normal running mode operates as described in detail above.

(59) In particular, the web 12 is transported in the machine direction by driving the target reel 11. Tension is maintained on the web 12 through the brake associated with the source reel 1 and the tension arm 3. The one or more sensors 6 detect the location of each portion 42 (whether real or virtual as described above) for the purpose of triggering the printer 40 to print data at a correct location in each portion 42 and also for the purpose of triggering the quality control unit 8 to read the printed data T in each portion 42.

(60) In the region of the web 12 extending in the machine direction between the dryer or curer 41 and the printer 40, the printed data items T are as yet uncured or undried as described above with respect to FIGS. 3 to 5. In the region of the web 12 downstream of the dryer or curer 41, the printed data T on the web 12 is dried or cured. The quality control unit 8 is located downstream of the dryer or curer 41 for reading the printed data T.

(61) The interaction of the elements shown in FIG. 6 with the control system 30 of FIG. 2 has been described above.

(62) As shown in FIG. 7, a short distance is just enough to pass through the dryer or curer all printing before print pause was entered. The short distance corresponds, generally, to the distance between the printer and the dryer or curer. After the short distance, web movement is also paused. The short amount of forward web movement in the pause mode is implemented by moving a tension arm to release web stored in the web feed path while a driver for driving feeding of the web is run for the short time and while a feed source of the web is paused. Referring to FIG. 7, a pause mode of the apparatus 20 and the control system 30 is explained. The controller 31 is configured to issue a pause command to relevant control modules. The source reel 1 is locked by the pause command from the controller 31 by operation of the brake through the brake reel module 33. At the same time as issuing a source reel 1 pause command to the brake reel module, a print pause command is sent to the printer module 38 to stop the printer 40 printing data on the web 12 at the next portion 42 and throughout the pause mode. The target reel 11 continues to be rotated to move the web 12 in the machine direction at the speed of the normal running mode with the source reel 1 locked and with the printer 40 stopped from printing data.

(63) The controller 31 is configured to issue a drive pause command to the engine reel module 40 to stop rotation of the target reel 11 after a delay has elapsed from when the print pause command and the source reel pause command issued. More specifically, the controller 31 is in communication with a memory storing a distance that the web 12 has to be moved after the print pause command in order to move all of the printed portions 42 in the stretch between the printer 40 and the dryer or curer 41 through the dryer or curer. The distance stored in the memory corresponds to at least or about the length of the web 12 between the printer 40 and the dryer or curer 41. The controller may be in communication with an encoder wheel that rotates as the web 12 moves to measure the distance that the web 12 has been fed in the machine direction since the print pause command. The controller can compare the measured distance of movement of the web 12 to the distance stored in the memory to determine when to issue the drive pause command. The encoder wheel may be embodied by the above mentioned web speed wheel of the web speed sensor.

(64) The web 12 is fed in the machine direction by a distance after the print pause command so that the printed data on each portion 42 extending between the printer 40 and dryer or curer 41 when the pause mode was initiated is moved at the normal running speed so as to be dried or cured by the dryer or curer 41. Once the last printed but not yet dried or cured item of data or portion 42 has passed through the dryer or curer 41, the drive pause command signal serves to stop rotation of the target reel 11 and the target reel 11 is also entered into a locked state. In a preferred embodiment, the target reel 11 is entered into a locked state by application of a target reel brake.

(65) The distance between the printer 40 and the dryer or curer 41 is sufficient to ensure that the dryer or curer 41 does not cause drying or curing of ink in the printer 40. The distance may be 5 cm or greater, 10 cm or greater, 15 cm or greater or 20 cm or greater and may also be 50 cm or less, 40 cm or less or 30 cm or less. The distance may correspond to 5 portions 42 (data items) or more, 10 portions 42 or more or 15 portions 42 or more. The portions 42 may, for example, be 10 mm in length or greater and up to 150 mm in length, with one particular data item being printed per unit length.

(66) The web 12 continues to run in the machine direction for about the distance between the printer 40 and the dryer or curer 41, even when the source reel 1 is rotationally locked. The web 12 is allowed to move by the tension arm 3 freeing web stored between adjacent (in the machine direction) guide rollers 4 and the tension roller 13. That is, the tension roller 13 moves against the bias of the tension arm toward adjacent guide rollers 4 to free sufficient web 12 to allow the web 12 to move the machine directional distance from the printer 40 to the dryer or curer 41.

(67) Once the cause of the pause mode is removed (e.g. maintenance operation on camera of quality control unit 8 or on the printer 40 or on the dryer or curer 41 or some other maintenance operation requiring the apparatus 20 to be paused), the apparatus 20 and the control system 30 is to re-enter the normal running mode in order to print the remainder of the portions 42 with printed data T. The pause mode shown in FIG. 7 has ensured that all printed data has been properly cured and dried and so has lead to the quality control unit accepting this printed data T as normal and readable. However, there is a region 45 of unprinted or blank web 12 extending in the machine direction between the printer and the dryer or curer 41 that has not received printed data.

(68) The preferred implementation of the present invention follows the pause mode with a resume mode bridging in time the pause mode and the normal running mode. In the resume mode, the web 12 is moved backwards so that the blank or unprinted region 45 is upstream of the printer 40. In this way, the normal mode of the apparatus 20 and the control system 30 can start and continue without any portions 42 in the winding 10 missing printed data.

(69) In the state depicted in FIG. 8, the web is moved backwards, by operation of the tension arm, to move the printed part of the web to a location upstream of the printer. In this way, printing can resume upon restart of forward running of the web without wasting any web as a result of stretches of unprinted web. A sensor is provided to allow detection of portions of the web representing locations of the web to be printed upon. The sensor is positioned upstream of the printer to assist timing of resumption of printing on the web. Referring to FIG. 8, the resume mode is explained in greater detail. In the resume mode, the controller 31 issues a resume mode command to the engine reel module 40 resulting in the target reel 11 being unlocked and in a free wheel state in the reverse direction. The tension arm 3 is biased away from the guide rollers 4 and thus biased to take up any slack by pulling the tension roller 13 away from the guide rollers 3. The bias may be through the weight of the tension arm 3 or hydraulic or other power assisted pressure. In the free wheel state of the target reel 11 and with the source reel 1 still rotationally locked, the tension arm 3 acts on the web 12 to pull the web 12 in the counter machine direction. The web 12 is caused to move to a location upstream (relative to the normal running mode machine direction) of the printer 40. The control system 30 and the apparatus 20 are now able to restart the normal running mode without missing any predetermined printing locations or portions 42, as explained in greater detail below. The pull back distance of the resume mode may be determined based on the feed distance that the tension arm 13 operates on the web 12 as a result of a change in potential energy caused by moving the weight upwards by a certain distance in the pause mode. Alternatively, the controller 31 may communicate with the above described encoder wheel to move the web 12 backwards by a target distance that can be measured by the encoder wheel. The controller 31 can communicate with the tension arm 13 to achieve the target distance.

(70) As shown in FIG. 9, resumption of the normal running mode has taken place without unprinted parts of the web occurring as a result of the backward movement step in the resume mode. The proper timing of restarting the printer is facilitated by the sensor, so that printing on the same web portion as has already been printed on in the previous normal mode is avoided and missing web portions from printing between successive normal modes is also avoided. Referring to FIG. 9, the apparatus 20 and control system 30 are shown in the normal running mode. More specifically, the controller 31 is configured to issue a restart command to the brake reel module 33 to release the lock on the source reel 1. The controller 31 is also configured to issue a restart command to the engine reel module 40, thereby the target reel 11 from the locked state, and to set the normal web speed, which is the same speed as before the pause mode was entered. The engine reel module 40 is configured to operate a motor for driving the target reel 11 at the set speed. The web is thus transported in the machine direction at the target speed.

(71) The controller 31 is configured to implement the normal running mode as described above with reference to FIGS. 1 and 2. In particular, the one or more sensors 6 are configured to detect a machine directional position of each portion 42 and the associated sensor module 35, 36 reports that position information to the controller 31. The controller 31 is configured to time a print signal to the printer module 1 so that the first portion 42 is printed on, wherein the first portion is positioned adjacent upstream of the last printed portion 42 printed before the pause mode was entered. The controller also uses the position information to time the quality control module 39 as previously described.

(72) In the normal running mode, with the web tension set at least in part by the brake applied to the source reel 1 (according to the previously described web tension feedback control), the tension arm 3 and the associated tension roller 13 moves back to its normal position, which is intermediate the position of the tension arm 3 during the paused mode and the position of the tension arm 3 during the resume mode. That is, a relatively large amount of web 12 is stored between the tension roller 13 and the guide rollers 4 during the resume mode, a relatively small amount of web 12 is stored during the pause mode and a relatively intermediate amount of web 12 is stored during the normal running mode.

(73) As can be appreciated from FIG. 9, the pause and resume modes of the present embodiment allow each portion 42 of the web 12 to be successfully printed on and avoids printing twice on the same portion 42. In this way, a complete reel of printed web 10 can be obtained without blank portions 42 and without portions 42 printed with data rejected by the quality control unit 42, even when a pause mode is entered during printing.

(74) Various alternatives could be provided to the above described embodiments, as would be conceived by the skilled person when provided with the present disclosure.

(75) For example, the tension arm 13 may be power assisted. This means that the tension arm 13 can be biased against the web 12 with a lower force during the normal running mode and with a larger force during the resume mode. In this way, the full force required to reverse the web 12 is not applied during the normal running mode to protect from damaging or breaking lower strength webs.

(76) During the resume mode, instead of being operated in a free wheel position, the target reel may be power assisted as the feed reel is counter fed under action of the web storage part. This could be useful in mitigating the effects of friction associated with free wheeling the target reel.

(77) In an embodiment, there are multiple source reels and multiple target wheels that are running in parallel, and each could operate the present normal, pause and resume running modes.

(78) In another embodiment, there are a plurality of webs running in parallel between the same source and target reels, which may also require a corresponding plurality of printers dryers or curers. Such an embodiment would also operate the presently disclosed normal, pause and resume modes.

(79) In another embodiment, there is a web 12 that is sufficiently wide that a plurality of portions 42 are spaced in the cross machine direction of the web 12, perhaps printed by a corresponding plurality of printing units 7 spaced in the cross machine direction. In this way, a plurality of parallel portions 42 can be printed. That is, the web can divided into a grid of cross directionally spaced and machine directionally spaced portions 42, e.g. labels or stamps. Again, in this embodiment, a normal running mode would be operated in which the wider web is unwound from a source reel 1 and wound about a target reel 11, with intermediate printing and drying or curing steps. This embodiment would also operate pause and resume modes as described herein. Such modes would be especially important in view of the multiplied number of data portions 42 between the printer 40 and the dryer or curer 41 at any given time as a result of there being not just m data portions 42 in the machine direction, but also n data portions 42 in the cross machine direction, giving a total data portions 42 of nm.