EP4252075A1

EP4252075A1 - Printing plates with printing structures having multiple elevations and, systems and process for manufacture, and methods for use of the same

Info

Publication number: EP4252075A1
Application number: EP21820166.3A
Authority: EP
Inventors: Robert Bruce; Wolfgang Sievers; Thomas Klein; Shahar Golan; Ben Ezra BARRY; Pascal Thomas
Original assignee: Esko Graphics Imaging GmbH
Current assignee: Esko Graphics Imaging GmbH
Priority date: 2020-11-24
Filing date: 2021-11-24
Publication date: 2023-10-04
Also published as: WO2022112342A1

Abstract

Processes and systems for making a flexo plate (2302) with a plurality of plate structures (2304) having a plurality of different elevations relative to the plate floor, including a first set of printing structures having a top elevation at a first (e.g. uppermost) level of the plate and at least a second set of printing structures having a top elevation at a second elevation above the plate floor below the first elevation but above the plate floor. In some embodiments, the second set of printing structures may form an indicator structure having at least one elevation configured to print conditionally after a predetermined amount of plate wear or upon receiving greater than a desired amount of contact pressure (2310, 2312). In other embodiments, the first set of printing structures correspond to relatively high ink coverage areas and the second set of printing structures correspond to relatively low ink coverage areas.

Description

PRINTING PLATES WITH PRINTING STRUCTURES HAVING MULTIPLE ELEVATIONS AND, SYSTEMS AND PROCESS FOR MANUFACTURE, AND METHODS FOR USE OF THE SAME

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application claims priority to U.S. Provisional Application Ser. No. 63/117,659, filed November 24, 2020, titled PRINTING PLATES WITH CONDITIONAL PRINTING INDICATORS, SYSTEMS AND PROCESS FOR MANUFACTURE, AND METHODS FOR USE OF THE SAME, and U.S. Provisional Application Ser. No. 63/117,826, filed November 24, 2020, titled PRINTING PLATE WITH PRINTING STRUCTURES HAVING MULTIPLE ELEVATIONS AND SYSTEMS AND PROCESSES FOR MAKING THE SAME, both of which are incorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

Many printing press technologies require tools that participate in the process of transferring ink from the ink source to the substrate on which printing is to be done. Some of the tools are made to accommodate a specific printed design, while others are applicable to multiple different designs or even generic. Most of these tools have a finite lifetime, during which they degrade until they are finally replaced with new or refurbished tools. An example of specifically designed tools is the printing plate, which is patterned according to a specific graphic design. Examples of tools that can be used for many different designs are anilox rollers, while generic tools include blankets and ink jet print heads.

Changes In tools, caused by physical degradation, damage or malfunctions can be gradual or sudden, and can occur during use on the press, during cleaning, during moving between the press and the storage facility, and as a function of time and other effects. Most changes are expected to impact the quality of the print on the substrate, with gradual or immediate effect. Such degradation in print quality can be detected on the press itself by Automated Inspection Systems such as AVT Apollo, and once detected can be used as a basis for either automatic or manual root cause analysis, in order to Identify the press component that requires corrective action. If the print defect is determined to be caused by one of the tools mentioned above, there may be a need to replace it immediately or at some later point in time. A tool may need to be replaced even if it does not yet create a noticeable print defect, but rather shows signs of degradation in performance.

The current most common practice is to replace expendables (e.g. parts that are eventually replaced, sometimes also referred to as "dispensable" or "replaceable" parts) based on some amount of utilization - eters (or other unit of length in the machine direction) of material printed, is a common measurement. If a printing plate has been used for some pre-defined amount of printing (e.g. a number of meters of printed production), it may be discarded and a new one ordered to be ready for the next occasion on which the design is to printed. An anilox may be cleaned based on one defined number of meters printed, and refurbished upon a second threshold of meters printed.

Many tools have reasonably expected lifetimes, either defined by the manufacturer or known to printers through experience. Lifetime is impacted by the interactions between the tools and other components, such as ink and substrate, and thus may depend also upon the graphic content of the printer image. The complexity of the interactions makes it difficult for printers to make exact predictions as to when a tool will deteriorate to a degree that it creates damage to the print, and thus a rule of thumb is applied, within a policy that aims at ensuring maximum press utilization with sufficient quality of product. For example, white inks are more aggressive to anilox surface than most other colors of ink, and so an anilox used on a deck with white ink will degrade faster than others. Printers do not currently have a way to follow which anilox roller has been used for how many meters with which color, as it is impractical to do so without an automated system that collects the information.

High press utilization requires making all preparations for a print job, such that there will be no need to stop printing mid-job in order to replace an expendable, such as plate or blanket. Therefore, printers prefer to replace tools earlier than really required, to be on the safe side. One key parameter for the replacement decision is the amount of usage of the tool, analogous to mileage on a car. Another parameter is the color of Ink and the position of that color in the print job. Printers, however, do not have a counter of how many meters each tool has been used for, as tools do not have individual identification markings, and their mileage is not recorded in any logging system . So, printers are in the dark, knowing only roughly for how many miles a plate or blanket has been used, and replace or refurbish before they need to, in order to avoid having a press waiting for a replacement part.

For generic tools, such as ink jet print modules, the quality of the print is a key factor - printers prefer to run their ink jet modules as long as they print sufficient quality, replacing them only when quality is too low.

When looking at the specifically designed tools, this policy of playing it safe is true mainly for long running print jobs, or for print jobs that are printed repeatedly periodically, using the same tools for the specific job. Such tools require a long time to manufacture, requiring action well in advance of when it is needed. Generic or almost generic tools, that can be used for all print jobs or for some print jobs, the replacement is less problematic, as they can be held in inventory and used for many different jobs.

The result of the above is that many tools are replaced prematurely, tooling costs are higher than they need to be, and printers do not have a clear picture of these costs. Thus, there is a need for better systems and methods for predicting when a printing tool should be replaced.

Various ways of tracking information during a printing plate making workflow are described in PCT Application Ser. No. PCT/EP2020/078112, filed October 7, 2020, which claims priority to U.S. Provisional Application Ser. No. 62/911,568, filed October 7, 2019, titled "SYSTEM AND PROCESS FOR PERSISTENT MARKING OF FLEXO PLATES AND PLATES MARKED THEREWITH." The foregoing PCT application, when filed in appropriate jurisdictions, may be filed as a continuation-in-part of U.S. Patent Application Ser. No. 16/559,702, titled SYSTEM AND PROCESS FOR PERSISTENT MARKING OF FLEXO PLATES AND PLATES MARKED THEREWITH, filed September 4, 2019, which is a continuation-in-part of U.S. Patent Application Ser. No. 16/433,873, filed June 6, 2019, which is a continuation-in-part of PCT Application Ser. No. PCT/EP19/052536, filed 1 February 2019, which claims priority to U.S. Provisional Patent Application No. 62/653,972, filed 06 April 2018, all titled "METHOD FOR PERSISTENT MARKING OF FLEXO PLATES WITH WORKFLOW INFORMATION AND PLATES MARKED THEREWITH." the contents of all of the foregoing are incorporated herein by reference In their entirety for all purposes, and may be referred to herein collectively as the "Esko Persistent Marking Disclosures."

The foregoing Esko Persistent Marking Disclosures describe exemplary systems for making a flexographic ("flexo") plate. Exemplary systems comprise a plurality of processing machines, each processing machine configured to perform one or more process steps in a workflow, including at least an imaging step, a curing step, a washing or other non-cured-polymer-removal step, a printing step, and optionally, a cutting step, a storage step, or a combination thereof, each processing machine having a controller and at least one variable operating parameter controlled by the controller. The system includes means for providing machine-readable indicia on the flexo plate. The machine-readable indicia are configured for persistent readability downstream of the washing (and cutting, where present) steps without printing in the printing step. The machine-readable indicia may embody information including at least a plate identifier and instructions corresponding to the at least one variable operating parameter for each of the processing machines or information corresponding to an address in computer storage where the information resides.

The means for providing the indicia may comprise a computer programmed with instructions for embedding information into a code, such as a 2-dimensional code such as a QR code, a barcode, or any machine readable code known in the art, as well as a computer programmed with instructions for providing information formatted for embedding into a magnetic stripe or into a chip, such as an RFID chip, capable of being read by any reader known in the art. The means for providing the code may further comprise a printer for printing a 2-D code, an imager for embedding the code into a printing plate such that the code will be readable after plate processing, as well as after the full set of plate processing steps to which that plate is configured to be processed. The means for providing an RFID code comprises machines for writing information onto an RFID-readable chip and machines for writing information into a magnetic stripe, as are known in the art, along with any of the processing equipment known in the art required for fabricating an RFID chip and accompanying antenna(s) into a fully functional RFID module or for creating a magnetic stripe and applying the stripe to a surface.

The indicia may be disposed in a strip of polymer in the plate. In one embodiment, the indicia may be in a portion of the plate that is later cut off. In some embodiments, the indicia may be disposed on a floor of the plate using areas of presence and absence of polymer in the plate floor, and/or by clusters of microdots arranged according to the code.

A plurality of readers are configured to read the indicia on the flexo plate, including at least one reader in communication with each controller of each processing machine. The reader may comprise a mobile device, such as a mobile phone, a tablet computer, or the like, having a camera and programmed with instructions to capture an image of the code. The mobile device may have instructions stored thereon for converting the image information to the information readable by the controller and/or information displayed on a display and readable by a human operator, or the mobile device may communicate over a network, such as a wireless network, to a central processor that converts the image to the information readable by the controller. The information for instructing the controller may be transmitted to the controller by the mobile device directly upon conversion of the image information to such instructions, or by the central processor to the controller upon receipt of the image from the mobile device, or by the central processor back to the mobile device, and then to the controller. In other systems, the reader may be directly connected to the processing machine and dedicated to that machine. In some embodiments, including for mobile devices or dedicated readers, the reader may be connected to or in communication with the machine via a wired connection or via a local wireless connection, such as via Bluetooth technology.

Exemplary controllers are configured to receive from the reader instructions corresponding to the variable operating parameters stored in or linked to the indicia and to control the processing machine in accordance with that at least one instruction. Such a controller may comprise a computer processor, accompanying media for storage of machine-readable instructions, and accompanying connections to the various portions of the processing machine in the workflow for conducting the process, ail of which components are well known in the art. The controller is programmed with instructions for receiving the information from the reader corresponding to the variable operating parameters, and incorporating those parameters into the control instructions provided by the controller to the various portions controlled thereby. It should be understood that the various portions controlled by the controller may be digital or analog devices, and to the extent necessary, the controller, or converters connected thereto, may convert control information from digital to analog and sensed feedback or monitoring from analog to digital formats, or vice versa.

In one embodiment, the workflow comprises a p roofer, and the information read from the indicia may include quality information indicative of printing properties associated with the plate.

Preferred embodiments also include a tracking controller for the workflow in communication with each of the plurality of readers. The tracking controller is configured to receive from each of the plurality of readers a communication indicative of time and in-process location of each flexo plate scanned by the reader. The tracking controller is further configured to provide an output indicative of real-time workflow positions of a plurality of in-process flexo plates. This output may be provided to a display screen connected to a central processor running instructions for operating the tracking controller, and may also be provided to the mobile devices operative as readers and/or to displays associated with any computer connected to a network connected to the tracking controller. The tracking controller comprises a processor and instructions, stored on computer readable media, for programming the processor to receive and store information from the plurality of readers and to process that information into a tracking report output.

Exemplary flexo plates created by the foregoing methods have machine- readable indicia on the flexo plate that is configured for persistent readability downstream of washing (and cutting, when present) steps without printing in a printing step of a plate workflow. The machine-readable indicia embody information including instructions corresponding to at least one variable operating parameter for each of a plurality of processing machines or embodying information corresponding to an address in computer storage where the instructions reside, as described herein.

The indicia may comprise, for example, a 2-dimensional code, such as a QR-code or a bar code, or an RFID module or a magnetic stripe. As described herein, the indicia may be disposed in a strip of polymer in the plate and/or may be disposed on a floor of the plate using areas of presence and absence of polymer in the plate floor, such as may be created by the use of clusters of microdots arranged in the LAMS layer so as to produce structures that rise above the floor slightly but not a printing level. And, as described herein, a first rendering of the indicia may be located in a first location on the plate and a second rendering of the indicia may be located on a second location on the plate, particularly wherein the first location is in a portion of the plate configured to be cut away from the plate and the second location is in a floor of the plate In an imaged area of the plate.

Computer readable media comprising non-transitory instructions readable by a machine, the instructions embodying any of the method and process steps as described above,

The machine-readable instructions may also comprise software, and machines programmed with such software, for the tracking controller. Such instructions may include instructions for providing machine-readable indicia on the flexo plate, including embodying in the indicia information corresponding to an address in computer storage. The instructions may also include instructions for storing, in the computer storage in a location identified by the address, information including at least one variable operating parameter for each of the processing machines. The program may also include instructions for receiving a communication from a reader of the indicia, and instructions for transmitting variable operating parameters to a corresponding one of the processing machines. Such a system may further include instructions for implementing a tracking controller for the workflow, the tracking controller in communication with each of the readers associated with each of the processing machines, and configured to receive communications from a plurality of readers configured to read the indicia from a plurality of in-process flexo plates in the workflow., wherein the indicia also includes a plate identifier. The communications received from the reader include locations of the in-process flexo plates. The programmed instructions further include instructions for providing real-time tracking of a workflow position for each of the plurality of in-process flexo plates based upon the communications and instructions for providing the tracking information as an output.

The Esko Persistent Marking Disclosures also describe flexo plate processing machines capable of performing at least one plate processing step in a plate processing workflow, the machines including a controller configured to receive a communication of one or more variable parameters for controlling the plate processing machine from a reader. The reader is in communication with the controller configured to read machine-readable indicia on a flexo plate to be processed, the indicia having embodied therein at least instructions corresponding to the variable operating parameters or information corresponding to an address corresponding to a location in computer storage where said instructions reside. The reader is configured to read the instructions embodied in the indicia or at the address corresponding to the information embodied in the indicia, and send the communication to the controller with the at least one variable operating parameter after obtaining the at least one variable operating parameter from reading the indicia or from querying the computer storage address corresponding to the information embodied in the indicia. The controller is also configured to control the processing machine based at least in part upon at least one variable operating parameter received from the reader. Readers for use in systems and processes for making a flexo plate with persistent markings have at least one detector configured to read the indicia from the flexo plate, such as a camera for reading a 2-D code, an RFID receiver and transmitter, or transceiver, for sending an RF signal and receiving an RFID response transmission from an RFID, or a magnetic stripe reader. A communication link in the reader is in communication with at least a controller of at least one processing machine configured to perform at least one of the process steps and a central processor configured to monitor the workflow. The reader also may have a processor configured to process the information read from the indicia, to communicate to the controller of the at least one processing machine the at least one variable operating parameter embodied in the indicia or stored at the address corresponding to information embodied in the indicia, and to communicate to the central processor information regarding the flexo plate read by the reader and a location of the reader within the workflow. The communication to the controller may be direct communication, or a communication that includes intermediate communications between the reader and a central computer. In particular, when the indicia represent an address on a network, the reader may be capable of reading the address, linking to the address, downloading the information from the address, and communicating the information to the processing machine. The communication to the processing machine may be by any wired or wireless communication method known in the art, including but not limited to those expressly described herein.

The processes, systems, computer program products as described herein may be configured to produce plates in which non-printing indicia is disposed on a floor of the plate as a presence or absence of polymer by any of a variety of methods. One process may comprise imaging the microdots during a LAMS layer imaging step. The microdots on the resulting plate may comprise a repeating pattern of alphanumeric characters, non -text graphics, or a combination thereof readable by a human and/or machine. The repeating pattern may include alphanumeric characters embodying information including job number, separation color, version, date, or a combination thereof. In one embodiment, the non-printing indicia comprises branding Information. In another embodiment, at least a portion of the non-printing indicia may be derived from at least two different types of microdots, such as a combination that creates visible indicia only in the presence of a difference in growth during curing between one of the types as compared to another of the types during processing of the plate. The difference in growth may result from suboptimal processing conditions with respect to at least one processing parameter, such as optical focus or cleanness, floor thickness, actinic radiation exposure parameters, or type of manufacturing equipment.

The non-printing indicia may be used for creating a line for use in alignment of the plate, such as a line positioned on the plate to align parallel to the intended running direction of the printing plate in the press.

Imaging information for the non-printing indicia may be stored in a layer of a PDF file. In some embodiments, image information for the non-printing indicia is combined with printing image information by combining two 1-bit image files. The combination of image information for the non-printing indicia may be combined with printing image information in a Raster Image Processor.

In some embodiments, the processes, systems, computer readable instructions and resulting plates created thereby, as described, may relate to providing the non printing indicia in the form of one or more elevations having a plate thickness above a predefined floor height, wherein the microdots corresponding to the non-printing indicia define the one or more elevations. In other embodiments, the non-printing indicia is provided in the form of one or more depressions having a plate thickness below a predefined floor height, wherein the microdots corresponding to the non printing indicia define the predefined floor height, An exemplary method for providing such depressions includes the steps of forming a subfloor at the thickness below the predetermined floor height by performing a back-exposure step at an energy intensity less than that required to create the predefined floor height, and then forming the predefined floor height by distributing a plurality of microdots in locations in which the predefined floor height is desired and by omitting microdots in locations in which the depressions forming the indicia are desired. Exemplary systems for making a flexo plate comprise processing equipment configured to perform one or more process steps in a workflow, the processing equipment having a controller and at least one variable operating parameter controlled by the controller, including one or more units of processing equipment configured for providing non-printing indicia on the flexo plate disposed on a floor of the plate using microdots. The processing equipment may include one or more of: imaging equipment, curing equipment, washing or other non- cu red-polymer-removal equipment, printing equipment, cutting equipment, or a combination thereof, and the non-printing indicia is configured for persistent readability downstream of the washing or other non-cu red-polymer-removal and optional cutting steps without printing in the printing step. In some embodiments, the non-printing indicia may be in the form of one or more elevations having a plate thickness above a predefined floor height, wherein the microdots corresponding to the non-printing indicia define the one or more elevations. In some embodiments, the non-printing indicia is in the form of one or more depressions having a plate thickness below a predefined floor height, wherein the microdots corresponding to the non printing indicia define the predefined floor height. Some embodiments include a flexo plate comprising non-printing indicia disposed on a floor of the plate in the form of areas of presence and absence of polymer in the plate floor defined by microdots. The non-printing indicia may be configured for persistent readability, such as downstream of washing or other non- cu red-polymer-removal and optional cutting steps, without printing in a printing step of a plate workflow. The non-printing indicia may be in the form of one or more elevations having a plate thickness above a predefined floor height, wherein the microdots corresponding to the non-printing indicia define the one or more elevations, or the non-printing indicia may be in the form of one or more depressions having a plate thickness below a predefined floor height, wherein the microdots corresponding to the non-printing indicia define the predefined floor height. The microdots may define alphanumeric characters or may define a repeating pattern of alphanumeric characters, non-text graphics, or a combination thereof. The alphanumeric characters may embody information including job number, separation color, version, date, or a combination thereof. The indicia may comprise branding information. The non printing indicia may comprise a line oriented to align with an element of plate processing equipment and operative to check alignment of the plate relative to the element of plate processing equipment.

Some embodiments may include non-printing indicia comprising a plurality of plate structures derived from processing at least two different types of microdots. At least a portion of the non-printing indicia may comprise the plurality of plate structures derived from the at least two different types of microdots in a combination that is visible because of a difference in size between plate structures derived from one of the microdot types as compared to plate structures derived from another of the microdot types. Such a difference in size may signal a presence of suboptimal processing conditions with respect to at least one processing parameter that is not in accordance with a specification. The suboptimal processing condition may relate to a processing parameter selected from the group consisting of: optical focus or cleanness, actinic radiation exposure parameters, type of manufacturing equipment.

At least a portion of the plurality of plate structures derived from the at least two different types of microdots may Include at least a first structure comprising microdots formed from a first, relatively greater number of pixels and a second structure comprising microdots formed from a second, relatively lesser number of pixels. In such embodiments, deviation of one or both of the first structure and the second structure from an expected height above the floor signals the presence of the suboptimal processing condition. A plurality of structures comprising microdots formed from different numbers of pixels may be provided, including at least one non printing microdot formed from a number of pixels expected to form non-printing indicia under optimal processing conditions and at least one printing microdot formed from a number of pixels expected to form printing indicia under optimal processing conditions, wherein actual height of one or both of the first structure and the second structure signals the suboptimal processing condition.

Non-transitory computer readable storage medium having data stored therein may represent instructions for imaging a first plurality of printing dots defining a screened image for making printing structures on a flexographic printing plate and a second plurality of non-printing microdots defining non-printing indicia. The non printing indicia define one or more features selected from the group consisting of: alphanumeric characters, non-text graphics, a repeating pattern of alphanumeric characters, a line, and indicia comprising at least two different types of microdots.

The non-printing indicia may comprise at least two different types of microdots including at least one type of microdots having a relatively greater size configured to be visible on a plate processed under optimal conditions and another type of microdots having a relatively lesser size configured not to be visible on a plate processed under suboptimal conditions. The non-printing indicia may comprise at least two different types of microdots in a combination configured to be visible on a plate processed under suboptimal conditions because of a difference in size between plate structures derived from one of the microdot types as compared to plate structures derived from another of the microdot types. The instructions relating to the non-printing indicia may be configured to generate one or more elevations having a plate thickness above a predefined floor height, wherein the microdots corresponding to the non-printing indicia define the one or more elevations in locations that do not provide support for a printing dot. The instructions may instead or also be configured to generate non printing indicia is in the form of one or more depressions having a plate thickness below a predefined floor height, wherein the non-printing microdots define the predefined floor height.

A process for making a flexo plate comprises non-printing indicia disposed on a floor of the plate using areas of presence and absence of polymer in the plate floor, wherein the non-printing indicia is disposed on a floor of the plate and the process comprises forming the non-printing indicia via exposure to actinic radiation from a back, non-printing side of the plate. The non-printing indicia may include alphanumeric characters, non -text graphics, a machine-readable code, a line, and combinations or repeating patterns of any of the foregoing.

The process may comprise providing a primary back exposure and an additional back exposure. In embodiments in which the non-printing indicia comprise areas of presence of polymer in the plate floor, the process may comprise forming the plate floor using the primary back exposure, and forming the non-printing indicia raised above the plate floor using the additional back exposure. In embodiments in which the non-printing indicia comprise areas of absence of polymer in the plate floor, the process may comprise forming a subfloor corresponding to a height of the non printing indicia using the primary back exposure, and forming the plate floor using the additional back exposure.

The primary back exposure may be performed before the additional back exposure, and the additional exposure may be performed after the primary back exposure but before the front side exposure. The primary back exposure may be provided by a first exposure source and the additional back exposure may be performed by a second exposure source. The first exposure source and the second exposure source may be spaced apart from one another in a fixed relationship, in which the process comprises causing relative movement between the plate and the first and second exposure sources. Front side exposure may be provided by a third exposure source spaced from a front side of the plate in a fixed relationship relative to the first and second exposure sources.

The additional back exposure may be provided by an LED matrix comprising a plurality of individual LED units, a digital light processing (DLP) unit, or by directing radiation from one or more sources through a masking component, such as a liquid crystal diode (LCD) matrix or a film. The additional back exposure may be provided by directing radiation to an imaging plane disposed above the plate floor. The non printing indicia may comprise structures comprising a plurality of individually definable microdots or may be continuous embossed structures.

The additional back exposure and the primary exposure may be provided simultaneously, or the additional back exposure may be provided in a different step than the primary exposure. The additional back exposure may be performed over an area of the plate smaller than an entire area of the plate, in which case the process may comprise selecting an area of the plate for receiving the additional back exposure that avoids the non-printing indicia interfering with printing features.

One system for making a flexo plate by curing a photopolymer plate with actinic radiation comprises a front side exposure system configured to direct actinic radiation to a front side of the printing plate for creating printing features defined above a floor of the plate, and a back side exposure system configured to direct primary actinic radiation and additional actinic radiation to a back side of the printing plate for creating the floor and non-printing features raised or depressed relative to the floor. The back exposure system may comprise an LED matrix for providing the additional actinic radiation, and may further comprise optics configured to focus radiation from the LED matrix to a desired plane relative to the plate, which plane may be above the plate floor.

In some embodiments, the backexposure system comprises a primary back side radiation source configured to provide the primary actinic radiation and an additional back side radiation source configured to provide the additional actinic radiation. The primary back side radiation source and the additional back side radiation source may be spaced apart from one another at a first spacing in a fixed relationship, in which case the system may further comprise means for causing relative movement between the plate and the primary and additional back side radiation sources. The front side exposure system may comprise a front side radiation source spaced from a front side of the plate in a fixed relationship at a second spacing relative to the primary back side radiation source, and the means for causing relative movement may be further configured to cause movement between the plate and the front side radiation source. The first spacing and second spacing may be adjustable.

The back exposure system may comprise a DLP matrix configured to supply the additional actinic radiation. In other embodiments, the back exposure system may comprise a source of actinic radiation and a masking component - such as a liquid crystal diode (LCD) matrix or film — disposed between the source and the plate. In such configurations, the source is configured to emit actinic radiation toward the masking component and the masking component is configured to transmit the additional actinic radiation to the plate.

An exemplary flexo plate may thus having printing structures formed of cured photopolymer having a printing level above a floor of the plate and configured to print in a printing step of a plate workflow; and non-printing indicia structures configured for persistent readability without printing in the printing step of the plate workflow.

The non-printing indicia are disposed on a floor of the plate in the form of areas of presence or absence of cured photopolymer relative to the plate floor, and may comprise embossed, continuous features not defined by discrete microdots.

A non-transltory computer readable storage medium may have data stored therein Including a first set of instructions for imaging a first plurality of printing dots defining a screened image for making printing structures on a flexographic printing plate via exposure to actinic radiation from a front side of the printing plate and a second set of instructions for imaging non-printing indicia via exposure to actinic radiation from a back side of the printing plate, the non-printing indicia defining one or more features selected from the group consisting of: alphanumeric characters, non text graphics, a machine readable code, a line, and combinations or repeating patterns of any of the foregoing.

A process for making a flexo plate includes providing non-printing indicia disposed on a floor of the plate using areas of presence and absence of polymer in the plate floor, wherein the non-printing indicia are disposed on a floor of the plate. The process comprises forming the non-printing indicia, at least in part, via exposure to actinic radiation from a back, non-printing side of the plate. The non-printing indicia may be continuous embossed structures. The process may include providing a primary back exposure and an additional back exposure. The non-printing indicia may comprise areas of absence of polymer In the plate floor, in which the process comprises forming a subfloor corresponding to a height of the non-printing indicia using the primary back exposure, and forming the plate floor using the additional back exposure. In another embodiment in which the non-printing indicia comprise areas of absence of polymer in the plate floor, the process comprises creating a plurality of non-printing-feature-sized apertures in an exposure mask with an absence of such features in a location corresponding to the non-printing indicia. The plate is then exposed through the exposure mask, such that the plate floor in areas aligned with the non-printing-feature-sized apertures has a first, relatively higher height, and the plate floor In an area aligned with the absence of such features has a second, relatively lower height. The raised floor may be created by a combination of front side and back side exposure, by back side exposure only, or use of front side exposure only.

In short, all of the foregoing concepts, as previously disclosed in the Esko Persistent Marking Disclosures, provide background for the invention as described, and any aspects of the foregoing may be incorporated in apparatus, methods, and processes described for the first time herein.

SUMMARY OF THE INVENTION

One aspect of the invention relates to a process for making a flexo plate. The process comprises providing a plurality of plate structures having a plurality of different elevations relative to the plate floor, including at least one set of printing structures having an elevation at an uppermost level of the plate and at least one conditional printing structure comprising an indicator structure having a plurality of elevations, including at least one elevation lower than the uppermost level and higher than the plate floor. The conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure greater than an amount of contact pressure required for image printing. The plate may have a plurality of contact pressure indicator structures each having different elevations. The one or more indicator structures may include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation. The one or more second-tier structures may comprise a wear indicator, such as a wear Indicator comprising a plurality of steps at different elevations and/or a sloped line sloping from a first end at a first elevation to a second end at a second elevation. The wear indicator may include a plurality of features that form a code. The one or more first- tier structures may form a printed watermark and the one or more second-tier structures may comprise a replacement printed watermark.

In embodiments, the one or more indicator structures may be disposed on a prefabricated structure formed apart from the printing plate, wherein the process further comprising attaching the prefabricated structure to the plate floor. The process may include creating a floor-level attachment pad in the plate to receive the prefabricated structure. The pad may have informational indicia about the prefabricated structure to be received, such as an identifier of a specific prefabricated structure or type of prefabricated structure, an orientation of the prefabricated structure, or a combination thereof. The floor-level attachment pad and the external structure may have mating non-planar features at an interface between the attachment pad and the external structure, which mating non-planar features may strengthen anchoring of the prefabricated structure to the attachment pad relative to an interface without such features, provide orientation of the prefabricated structure on the attachment pad, or a combination thereof. The prefabricated structure may be attached to the floor with a curable adhesive, wherein the process includes performing a curing step to affix the prefabricated structure to the plate by polymerizing the adhesive.

Embodiments may include creating the one or more indicator structures from a back side of the plate. The different elevations of the plurality of plate structures may be created by providing correspondingly different stain levels on a LAM layer of the plate. The process may include performing a single imaging step on a single LAM to create the different elevations of the plurality of plate structures. The process may also include performing a single UV exposure process, the single UV exposure process having one or more exposure steps. The process may further comprise providing image information to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for Imaging that pixel.

In embodiments, the step of creating the different elevations of the plurality of plate structures comprises exposing the plate with respective different energy levels of actinic radiation. The different energy levels may be provided using an UV LED exposure unit configured to produce the respective different energy levels. The UV exposure unit may be configured to move relative to the plate. Providing the different energy levels may include interposing a film having respective different levels of transmissivity between an actinic radiation source and the plate. The process may include providing the film and the actinic radiation source in a handheld unit having a switch for triggering emission of the actinic radiation through the film onto the plate.

Another aspect of the invention relates to a flexo plate. The plate comprises printing structures formed of cured photopolymer having a printing level above a floor of the plate and configured to print in a printing step of a plate workflow; and one or more indicator printing structures disposed at one or more elevations above the floor of the plate, but beneath a topmost level of the plate, and configured to print as an indicator of a condition of the printing plate or a printing system in which the plate is mounted. The indicator printing structures comprise embossed, continuous features not defined by discrete microdots.

Still another aspect of the invention relates to a non-transitory computer readable storage medium having data stored therein including a first set of instructions for imaging a first plurality of printing dots defining a screened image for making routine printing structures on a flexographic printing plate via exposure to actinic radiation from a front side of the printing plate and a second set of instructions for imaging one or more indicator printing structures via exposure to actinic radiation, the indicator printing structures defining a line or series of steps extending from a first elevation to a second elevation. Yet another aspect of the invention relates to a flexo plate product produced by the process as described herein. An exemplary flexo plate has a plurality of types of plate structures at a plurality of elevations relative to the plate floor. The plate structures comprise printing structures having an elevation at an uppermost level of the plate and at least one conditional printing structure comprising an indicator structure having a plurality of elevations. At least one elevation is lower than the uppermost level and higher than the plate floor, wherein the conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure in excess of a predetermined threshold. The at least one indicator structure may include a plurality of contact pressure indicator structures each having different height levels. At least one indicator structure may include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation, such as wherein the one or more second-tier structures comprise a wear indicator. The wear indicator may include a plurality of steps at different elevations, a sloped line sloping from a first end at a first elevation to a second end at a second elevation, and/or a plurality of features that form a code. The one or more first-tier structures may form a printed watermark and the one or more second-tier structures may comprise a replacement printed watermark.

Another aspect of the invention includes a system for detecting wear of a flexo plate. The system comprises one or more wear indicator structures having at least a portion at an elevation not intended to print unless adjacent printing structures or an adjacent portion at a higher elevation experience a loss of elevation. The system may include a machine vision system configured to detect printing of the wear indicator structures.

Still another aspect of the invention relates to a system for tracking printing system metrics. The system comprises a printing plate as described herein; a reader configured to read the machine-readable unique identifier; a database stored in computer memory comprising a record associated with each printing system tool; a machine vision system for detecting a printed shape printed by the printing system on a substrate, the printed shape corresponding to the at least one indicator structure; and a processor connected to the reader and configured to evaluate a property of the printing plate based upon the printed shape on the substrate. The printed shape may be undetectable by a human naked eye.

Yet another aspect of the invention relates to a handholdable device for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation. The handholdable device includes a source of the actinic radiation configured to emit a predetermined dose of actinic radiation energy per unit time; a film with a plurality of regions, each region having a different transmissivity of the actinic radiation energy calculated to transmit an amount of actinic radiation energy required to cure a photopolymer plate to one of the respective plate elevations when exposed to the predetermined dose of actinic radiation for a predetermined amount of time; and a trigger for causing the source to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time.

A related aspect of the invention includes a process for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation, including the step of providing the handholdable device as described, disposing the handholdable device adjacent a surface of the photopolymer printing plate; and actuating the trigger to cause the device to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time. The handholdable device may be disposed adjacent a back surface or a front surface of the photopolymer printing plate when actuating the trigger. In embodiment, the one or more indicator structures may comprise continuous, non-pixelated structures.

Yet another aspect of the invention relates to a process for making a flexo plate. The process includes providing a plurality of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising a first set of printing structures having a top elevation at a first elevation above the plate floor corresponding to relatively high ink coverage areas and a second set of printing structures having a top elevation at a second elevation above the plate floor below the first elevation but above the plate floor corresponding to relatively low ink coverage areas. The first elevation may be at an uppermost level of the plate.

In embodiments, correspondingly different stain levels may be provided on a LAM layer of the plate to create the different elevations of the first elevation and the second elevation. A single imaging step may be performed on a single LAM to create the different elevations of the first elevation and the second elevation. The process may include performing a single UV exposure process having one or more exposure steps. Image information may be provided to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for imaging that pixel.

Another aspect of the invention relates to a flexo plate product produced by the process as described above, or any flexo plate having a plurality of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising a first set of printing structures having a top elevation at a first elevation above the plate floor corresponding to relatively high ink coverage areas and a second set of printing structures having a top elevation at a second elevation below the first elevation but above the plate floor corresponding to relatively low ink coverage areas.

Still another aspect of the invention relates to a system for Imaging a laser ablatable mask (LAM). The system includes an imager comprising a laser configured to emit a beam in a path with an amount of energy operable to ablate at least a desired percentage of the LAM in the path, and a processor configured to control the imager based upon pixel-based imaging information. A computer memory, accessible to the processor, is configured to store the imaging information, which includes information identifying a location corresponding to each pixel and the amount of energy to be applied to ablate the mask in the location corresponding to the pixel.

The system is configured to image the LAM to create different stain levels, including a first stain level corresponding to a first plurality of plate structures having a first elevation above a floor of the plate and a second stain level corresponding to a second plurality of plate structures having a second elevation at a level below the first elevation but above the plate floor. In some embodiments, the first elevation is at an uppermost level of the plate, and/or the second elevation Is a non-printing elevation. The second plurality of plate structures may comprise conditional printing structures. The conditional printing structures may include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation. In embodiments, the one or more first-tier structures form a watermark and the one or more second-tier structures comprise a replacement watermark. The conditional printing structures may define a plurality of elevations below the first elevation and above the plate floor. The plurality of elevations may comprise a plurality of steps at different elevations, including as a sloped line. The conditional printing structures may comprise an indicator, such as a wear indicator, such as a wear indicator that comprises a plurality of features that form a code. In other embodiments, the first plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas and the second plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas.

Still another aspect of the invention relates to a n on-transitory computer readable storage medium having machine-readable instructions stored therein for causing a processor to image a laser ablated mask (LAM) on a photopolymer printing plate. The instructions cause the processor to access a computer memory storing the imaging information that includes information identifying a location corresponding to each of a plurality of pixels, and an amount of laser energy to be applied to an abatable mask in each location corresponding to the pixel. At least some of the plurality of pixels include information identifying a different amount of laser energy than at least some of the others of the plurality of pixels, each different amount of laser energy corresponding to a different percentage of stain level remaining on the LAM. The instructions further control an imaging laser to emit a beam corresponding to the identified amount of energy in the identified location for each pixel, the identified amount of laser ablation energy operable to ablate at least a desired percentage of the LAM in the path. The different percentages of stain levels remaining on the LAM correspond to stain levels that when the plate is exposed to actinic radiation through the mask, cause formation of a plurality of plate structures including a first set of plate structures having a top elevation at a first elevation above the plate floor and a second plurality of printing structures having a top elevation at a level below the first elevation but above the plate floor. The first elevation may be at an uppermost level of the plate, and/or the second elevation may be a non-printing elevation. In embodiments, the second plurality of plate structures may comprise conditional printing structures. In some embodiments, the conditional printing structures may include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation. In other embodiments, the one or more first-tier structures may form a watermark and the one or more second-tier structures may comprise a replacement watermark. In still other embodiments, the conditional printing structures may define a plurality of elevations below the first elevation and above the plate floor, such as a plurality of steps at different elevations, or a sloped line. The conditional printing structures may comprise an indicator, such as a wear indicator, including wherein a plurality of features that form a code. In still other embodiments, the first plurality of plate structures correspond to relatively high ink coverage areas and the second plurality of plate structures correspond to relatively low ink coverage areas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram depicting an exemplary embodiment of a workflow process with a tracking controller.

FIG. 2A is a schematic diagram depicting a plate having indicia read by a reader in communication with a controller in an exemplary workflow system.

FIG. 2B is a schematic cross-sectional diagram of an exemplary flexo plate having first and second indicia. FIG. 3 depicts an in-process polymer plate having a LAM and cones of cured polymer.

FIG. 4 depicts a micrograph of a plate 2000 having tilted cones among others still standing. FIG. 5 depicts a portion of a plate with cones not attached to the floor.

FIG. 6 depicts a plate with overlapping cones that create structures bonded to the floor but having a height below the top of the plate.

FIG. 7A depicts a height profile of a printing plate with a stack depicting corresponding print results at different contact pressures shown above the plate.

FIG. 7B depicts an enlarged portion of FIG. 7A.

FIG. 8 depicts a UV light source with a plurality of segments disposed relative the polymer piate floor with print contact pressure marks raising up from the floor cured by the light source, such as for a wear indicator. FIG. 9 depicts a profile of cured polymer for a plate having printing structures at a first elevation for relatively high ink coverage areas, printing structures at a second elevation for relatively low ink coverage areas, and non-printing structures at a third elevation, such as for forming non-printing indicia.

FIG. 10 is a graph depicting parameters of exemplary pixel cluster sizes and spacings for creating a feature elevation at a predetermined level above the floor on a designated plate using a squared pattern of mask openings arranged at a constant distance in a horizontal and a vertical direction.

FIG. 11 is an exemplary squared pattern of mask openings arranged at a constant distance in a horizontal and a vertical direction. DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures, FIG. 1 schematically illustrates a prior art workflow 100 having a plurality of process machines 110, 120, etc. each configured to perform one or more process steps in the workflow of creating a printing plate.

As depicted in FIGS. 2A and 2B, the applicant has previously disclosed a marking method and structure for flexographic printing plates 200 and their precursor states, which enables the association of up-to-all process-relevant information to the plate itself by attachment of indicia 212, 214 to the plate, and thereby enables controlling up-to-all process stages using this information. Preferably, the processing machines used for the plates are also configured with or in communication with a reader 220 configured to read the marks, and configured to receive process parameters required for the plate to be processed and to report the status of plates being processed to a central control computer 170, based upon information derived from reading the marks. Embodiments of the system thus enable monitoring and control of the complete platemaking process for all plates in the workflow chain from order intake to plate storage after printing.

While the parameters for RIPping and imaging are provided directly from a computer by a data file, the parameters for the remaining steps are ideally attached to the plate in accordance with aspects of the invention. Exemplary steps in the workflow may include a UV exposure step performed by a UV exposure system 110, a thermal or chemical processing step performed by thermal or chemical processing apparatus 120, a finishing step performed by finishing apparatus 130, a cutting step performed by cutting apparatus 140, mounting one or more cut portions of a plate onto a substrate with a mounting apparatus 150, and printing in a flexo process with a printer 160, using the substrate having the plate portions mounted therein. Additional steps may also be included in the workflow at the beginning or end, and interposed between any of the steps specifically depicted. For example, an imaging step typically precedes the UV exposure step, an ordering step typically precedes the imaging step, and a storage step follows the printing step. The blocks associated with each processing step are exemplary only, and a single machine may perform steps related to multiple blocks, or multiple machines may together perform the steps illustrated in a single block. Some steps depicted may be optional.

This attachment to a plate 200 may be accomplished, for example, using machine-readable indicia 212, which may be a 2D code such as a QR-code or a barcode, a radio-frequency identification (RFID) module, or a magnetic strip. One form of machine-readable indicia may comprise a 2D code in the form of alphanumeric characters readable by a human as well as configured to be captured by a camera and processed using text recognition software known in the art. Such embodiments have the advantage of providing a code on the plate that can be read and interpreted by both a human operator and a machine. The RFID module may be inserted into the polymer before or after curing at a spot of solid image area on the plate where the polymer is to be cured (and thus retained on the fully exposed plate). In exemplary embodiments with a magnetic strip, the strip is preferably attached to the rear side of the plate on the dimensionally stable PE layer of the plate, where the strip is positioned to contact a reading head mounted on the processing machine as the plate is processed. The magnetic strip may be attached as a completed strip formed by any method known in the art, or may comprise a magnetic ink dispensed directly onto the rear side of the plate. Although the indicia 212 is depicted as a QR code in the figures, it should be understood that the QR code in the figures is intended as a schematic representation application to any of the types of indicia described herein, or their equivalents.

Although certain indicia have been explicitly described, the term "indicia" is intended to have its broadest meaning of "an indication" or "distinguishing mark," without limitation to how that Indication or mark is capable of being read, and thus the "equivalents" of the indicia as expressly described are intended to be broadly construed. While certain machine- readable indicia or codes may take advantage of formats that are exclusively machine readable to permit a large volume of information to be stored in a small amount of space, it should be understood that the term "machine readable," as used herein to refer to indicia and codes, is not limited to indicia having a format that is exclusively machine-readable. Those of skill in the art will appreciate that human readable alphanumeric information is also machine readable by a reader equipped with suitable optical character recognition (OCR) functionality, and that the hardware and software for providing such functionality is well known in the art and becoming more ubiquitous. For example, many highway toll authorities now use character recognition of license plates as an equivalent to, a substitute for, or supplement to RFID pass technology. Furthermore, machine vision systems and human operators alike can also be trained to read non-alphanumeric graphic symbols to convey information that can be universally understood (e.g. the graphic symbols denoting recyclable materials or laundry care recommendations) . Thus, it should be understood that the terms "indicia" and "machine readable" are intended to be broadly interpreted to include, without limitation, in addition to the other types of indicia discussed in detail herein, printed or otherwise visible alphanumeric or graphical information configured to be read and comprehended by human operators as well as machines, as well as combinations of indicia that are exclusively machine readable with indicia that is both human and machine readable. One advantage of using machine-readable indicia that is also at least partially human readable, is that an experienced human operator may be able to process and act upon at least some codes faster than it would take that same operator to enlist the assistance of a machine.

In some embodiments, the code for a printed code, such as a bar code or a QR code or printed indicia comprising text and/or graphics readable by a human or machine, may be added during ripping the image file and is thus included in the content of the image information, such as in the .LJEN file or encrypted LENx file associated with an Esko PlatePrep workflow. Adding a code to an image file may be accomplished using, for example, Esko DeskPack™ barX software, which software comprises machine-readable instructions embodied in storage media, such as a hard drive, a flash drive, or any type of media, as is well known in the art. As described herein, the imaged information may be provided in the form of non-printing structures on the plate floor formed using microdots, including in the form of a non-printing watermark derived from the use of non-printing microdots in a printing portion of the plate. Such structures formed from microdots may be created on a flexo plate using an Esko® XPS exposure system.

The following examples refer to QR- codes as the exemplary information storage technology, but the invention is not limited to any particular information storage technology, and is applicable to any information storage technology known in the art capable of conveying the amount of information required to practice embodiments of the invention, and in particular, to any of the storage technology expressly described herein.

In preferred embodiments, all processing equipment 110 - 160 in the workflow 100 are provided with or connected to a scanner or other information capture device, herein referred to as a "reader," which allows reading the indicia to obtain the associated plate process parameters. Thus, in preferred embodiments, before starting the process or processing step, process information is scanned from the plate and the relevant process parameters are set accordingly. For example, where the indicia 212 comprises a visible code, such as a QR code or a barcode, the reader 220 may comprise a mobile device, such as a mobile phone, a handheld computer, a tablet, or the like. Although reader 220 is depicted as a "phone," it should be understood that the figure is intended to be a schematic representation of any applicable reader, and may comprise any type of reader known in the art suitable for reading the indicia provided. Thus, for example, where code 212 comprises an RFID tag, the reader comprises an RFID reader, and where code 212 comprises a magnetic stripe, the reader comprises a magnetic stripe reader. The technologies and apparatus associated with reading 2-dimensional printed codes, magnetic stripes, and RFID tags are well understood in the art. Reader 220 is connected to controller 230 of the apparatus for performing the identified process step. The connection between the reader and the controller may be a wired or wireless connection. An exemplary wireless connection may comprise a local wireless network running on computers local to a facility in which the processing step is located, or may be a network connected to a global information network or wireless communication network. Controller 230 may be programmed with instructions for translating the information derived from the indicia into the information required to set the corresponding parameters of the processing equipment, or the translation instructions may be contained in the reader. The information derived from the reader may be embedded directly in the indicia, or the indicia may comprise information corresponding to an address in computer storage on a network where the information resides in communication with the reader and the controller. The information corresponding to the address may be a URL, a process identifier, or a unique plate identifier. In an embodiment in which the information is a unique plate identifier, the system may be configured to use the unique plate identifier to find the corresponding instructions, such as using by using the plate identifier to query a lookup table that resides at a known address. In embodiments where tracking specific plates is not of interest, and where the processing instructions corresponding to the universe of plates to be processed have only a limited number of permutations, the information corresponding to the address may be a process identifier rather than a unique plate identifier. In such embodiments, the process identifier may be used for querying a corresponding lookup table of process instructions corresponding to each process identifier. In embodiments in which the instructions are embedded in the identifier, the indicia may also further embody a unique plate identifier, wherein the plate identifier may be used for tracking the plate or identifying the plate, such as with a mobile device, as described herein later.

Process information may include, for example and without limitation: the job name, customer name, printer's name, plate type, plate thickness, back exposure energy, preferred back exposure time, main exposure energy, preferred main exposure time, number of main exposure cycles, plate processing speed, plate processing temperature, plate cutting path, plate cutting speed, and the like.

Process information may be stored in the indicia 212, such as a QR code. Reading a QR code from a plate can be performed with an existing QR-code reader (i.e. a code scanner) known in the art. For example, a model C5PC003 code scanner from Wenglor is suitable for omnidirectional scanning of ID and 2D codes, including but not limited to ID codes (commonly referred to as "barcodes"), such as Code39, Code93, Codel28, UPC/EAN, BC412, Interleaved 2 of 5, Codabar, Postal Codes, Pharmacode, and 2D codes, such as DataMatrix ECC 0...200, PDF417, Micro PDF417, QR-Code, Micro QR-Code, Aztec Code, GS1 Data bar, and Dot code. The indicia used for providing the Information is not limited to any particular type of code. In order to increase contrast and readability of the code on the plate, light from a light source (not shown), such as a light typically associated with a camera flash for a mobile device, may be applied from the bottom or the top of the plate. In preferred embodiments, process parameters for different stages are embodied directly in the code such that each individual processing unit can derive instructions directly from the code on the plate without having to connect to a network. In other embodiments, the code may comprise a computer storage address where the process information is stored, and the reading step comprises reading the information, connecting to the storage address embedded in the information such as via a hyperlink, reading the information from the storage address, and communicating relevant stored information to the processing machine. As illustrated in FIGS. 2A and 2B, the information may be at least initially stored in a first indicia location 212, such as in the form of a QR code, which location Is disposed on a test strip 210 adjacent the image area 205 of a flexo polymer plate 200. This test strip may also contain register and color proof marks for setting up the press. While, preferably, the register marks and other marking on the test strip (and thus also the QR code, when placed on such a test strip) stay on the polymer plate together with the image for the entire life of the plate, in some embodiments it may be necessary to cut the test strip away from the plate to avoid printing the information on the test strip, such as a QR code, on the printing substrate. Embodiments to address this situation are discussed herein later.

Providing code information that is persistently readable during all process steps (e.g. imaging, curing, washing, printing, and optional cutting and storage steps) is a challenge in connection with washing processes associated with flexo plates, because most washing processes are solvent-based. The solvent not only removes non-cured portions of the flexo plate polymer, but it also removes ink of the type typically used on printed labels and marker pens. Thus, one aspect of the invention relates to providing a code configured to survive a washing step by making the code part of the image or by inserting information into cured portions of polymer. For example, an RFID device may be inserted into the cured portion of the polymer mechanically, or a magnetic strip may be disposed on the surface of the dimensionally stable layer on the rear side of the polymer plate where it is positioned to be read by a magnetic card reader head as is known In the art. Such an RFID device or mag strip must be capable of surviving the downstream processing steps, however. While adding coded information to the image enables persistence past the washing step, in some embodiments it is undesirable for the codes to be printed. Thus, preferred embodiments may include codes embodied in the plate in a way that is persistent past a washing step, but not printed in a printing step. In one embodiment, the code is added only in the plate floor, such that the details do not reach the printing surface, as described below. In another embodiment, the code is placed in a location beyond the desired portion of the printed image (e.g. in a test strip) and, In some cases, the code is transferred to another location prior to or during a cutting operation, as described below. As used herein, the "washing" step may refer to any non-cured-polymer- removal step that removes non-cured polymer from the plate. Such a "washing" process may include a traditional solvent (or water) washing step, or may also include a thermal method, such as those commonly associated with DuPont™ Cyrel^® FAST Thermal Workflow or MacDermid^® LAVA^® plates, as known to those of skill In the art. Thus, the phrase "washing step" as used generally herein should be understood to refer to any non-cured-polymer-removal step, absent explicit reference to specific washing processes.

INDICIA FORMED OF NON-PRINTING STRUCTURES

In some embodiments, to keep the information in the code on the plate 200, instead of being located on a plate top surface 202, the 2D code, such as a QR-code 214, may be positioned in the plate floor 204. The plate floor is built by polymer that has been cured from the backside of the plate, but it is not intended to print, thus the thickness of the floor stays below the level of the printing top surface of the polymer.

Although not limited to any particular method for providing the indicia, there are several preferred ways for providing indicia structures into the polymer. One preferred method is to provide the indicia via UV exposure through an imaged mask, such as via direct imaging In the mask. This method may place sunken structures on the printing surface level, or microdots that produce elevated structures on the floor or depressions relative to the floor. Another method is laser engraving, which may provide sunken structures below either the printing surface level or the floor level. Yet another method is to mill sunken structures below either the printing surface level or the floor level.

In some embodiments, a code 212 that resides below the top (printing) surface 202 of a test strip 210 of the plate 200 during some process steps may be transferred from the top surface to the floor surface 204. For example, code 212 may be scanned by the reader and the code or code image stored in a data file and then that data file may be used for instructing the cutting of a reproduction of the code image 214 into a floor portion 204 of the image area 205 of the plate while the plate is on the cutting table. As depicted in FIG. 2A, code 214 depicted in a lighter shade is intended to represent its location on the floor of the plate where it will not cause an image corresponding to the code to print when the top surface is used for printing. As depicted in FIG. 2B, code 214 (solid lines) may be cut into floor 204, such as formed by laser engraving or cutting with a milling head.

MICRODOTS AND NON -PRINTING WATERMARKS

Embodiments as referred to herein may be created using microdots in the LAMS layer during the exposure step, such that structures are formed in the plate at a level above the floor of the plate, but below the top printing level. A particular method for storing a code on the plate floor comprises using microdots, such as are disclosed in EP 1 557 279 Bl, incorporated herein by reference. The use of non-printing microdots for raising the printing floor to provide support for marginally printable image features is also well known, such as is described in U.S. Pat. No. 7,126,724.

The microdots as generally described, herein, however, are not intended to provide support, and are typically disposed in locations far enough away from printing dots so as not to provide such support. Rather, the microdots are used for creating non printing indicia having functionality as described further herein. Some embodiments described herein may include a combination of microdots providing support and not providing support, however.

The term "microdots" as used herein primarily refers to small mask openings in the LAMs layer of a flexo plate, wherein each opening is not wide enough to grow a printable screen dot in isolation (under normal power), but clusters of them (or single pixels with sufficient boost) are operable to raise the plate floor level. The term microdot may also refer to any dot used in any imaging step by any process capable of creating a non-printing dot structure on a plate, including but not limited to direct curing processes and non-LAMS mask-based processes. As used herein, the term "microdot" may be used to refer to a feature in the image information used by the imager for creating the plate or mask structure, as well as the plate structures formed thereby. In some embodiments, a cluster of microdots may be used to form sections of elevated floor relative to other sections of the floor that remain non-elevated and arranged in a formation resembling the dark and light sections in a QR-code or a barcode. In other embodiments, described in more detail below, microdots may be used to form the floor and an absence of such microdots may be used to provide depressions in the floor. In still other embodiments, microdots may also be used to create a combination of elevated and depressed structures relative to a predetermined floor level. The microdots in the mask result in microstructures (elevations or depressions) in the exposed plate.

As set forth in the Esko Persistent Marking Disclosures, non-printing indicia may include text and graphics in a repeating pattern that forms a "non-printing watermark." The non-printing watermark may comprise a graphic and text that repeats in a pattern (such as a grid, but not limited to any particular configuration). Text may include information regarding a job (e.g. "Job Number 1234"), the separation associated with the plate (e.g. "Cyan Plate"), the version of the plate (e.g. "Version 1") and a date associated with the plate (e.g. "18^th April 2019"). The invention is not limited to any particular type of text or graphics, however, and may include branding information such as logos or trademarks identifying the plate owner, plate designer, the maker of the workflow system that created the plate, or the like.

In some embodiments, the non-printing watermark may comprise only non-text graphics or only textual indicia. Graphical indicia may include any type of indicia as disclosed herein, including but not limited to machine- readable codes including but not limited to barcodes and QR codes.

The term "non-printing watermark" is used herein as an analog to the original definition of the term for the identifying images or patterns on paper that appear as various shades of lightness/darkness when viewed by transmitted or reflected light (at certain angles or atop a dark background), caused by thickness or density variations in the paper. Such watermarks are often visible in the paper constituting an original document, but not in reproductions (e.g. photocopies) made from that paper. By analogy, the non-printing watermark formed in accordance with embodiments of the invention may be more visible under certain conditions (e.g. reflected light at a certain angle) and comprise a variation in thickness of the plate, with the markings not reproduced in printed matter made by the subject plate.

The non-printing watermark indicia may be visible relative to the floor of the plate, and may be more visible in light transmitted through the plate or reflected at certain angles. The non-printing watermark indicia, having a relatively lesser height above the floor, is distinguishable from printable text, having a relatively greater height above the floor. Non-printing watermark structures using microdots give the ability to add non-printing information such as trademarks and logos to the polymer plate that identify the source of the plate, processing equipment, or other entities involved in the workflow to create the plate that is ready to print. Because using microdots create a challenge in RIPping the image file, imaging the mask, and curing the plates, the presence of microdots organized into visible structures may also serve as proof that high-quality equipment was used for manufacturing the printing plate, and may provide quality information regarding the manufacturing process. Thus, for example, microdot-based indicia may be used not only to provide proof of the plate's origin or proof the plate was made with a certain type of equipment, but also proof that the manufacturing process was successfully completed, including proof the floor thickness is correct, and proof the plate is / was mounted / aligned properly (e.g. on the printing cylinder).

In some embodiments, curing radiation may be introduced from the rear, non printing side of the plate, where the back exposure is applied. Before, or preferably after, the primary back exposure is applied, an additional exposure is applied using an imaging system comprising an actinic radiation source and any method of creating a spatial variation of the radiation intensity suitable to create an image of desired resolution. Exemplary systems may include;

• a UV-LED Matrix controlled to form images, letters or logos;

• a masking component, such as a film or liquid crystal diode (LCD) matrix that carries image information, disposed between a UV radiation source (e.g. matrix of UV LEDs, one or more fluorescent tubes) and the rear of the plate, wherein the masking component transmits UV radiation only at locations where logos or letters have to be created on the plate floor and blocks UV radiation transmission in all other locations; and

• a Digital Light Processor (DLP) comprising a plane of digital mirrors that Is illuminated by a UV radiation source imaged into the rear side of the polymer plate, with the image plane preferably located between the floor and printing surface of the plate, and more preferably, slightly above the floor.

It is advantageous in the back side exposure embodiments to focus the UV radiation on a plane slightly above the floor level (e.g. at a level where the top of the non-printing structures is desired). The back side radiation exposure may be controlled, such as with controller, to form graphic patterns, such as alphanumeric characters, logos, QR codes, barcodes, or any type of indicia known in the art, by turning individual LEDs in LED matrix ON or OFF during relative movement between the LED matrix and the plate, Controller may be the same controller used for creating the front side exposure, or a different controller or control module. In embodiments in which the non-printing image information is imposed using a masking component, the masking component may be a film or LCD matrix having transparent and non transparent areas.

The Esko Persistent Marking Disclosures disclose a number of different ways of making structures on a plate, any and all of which may be relevant to the invention as disclosed herein. The Esko Persistent Marking Disclosures also discuss use of various indicia, including but not limited to structures formed in the plate polymer, for providing information about the plate. The indicia may be used for monitoring the status of the workflow by software in a central computer, such as computer 170 depicted in FIG. 1. Each process stage 110, 120, etc. sends information to the central computer after scanning the code from the plate, such as reporting the time and place of arrival of the plate and the current processing status. Thus, the actual status of a job in the workflow can be determined immediately and exactly from the central computer. Certain plates may thus be identified and located instantly in the company workflow. The central computer 170 is programmed with software capable of processing all this information of different plates from different stages of production, such as for example the ESKO Device Manager. The code or indicia may also be read in-between process steps or after completion of the process steps, such as in a storage area or in a queue awaiting processing.

MOBILE DEVICE READERS The information stored in the indicia may be scanned and read by application software running on a mobile device, such as a mobile phone or tablet computer. As is known in the art, systems incorporating such mobile devices typically include a first portion of software running on the mobile device, with the mobile device in communication with a server over a communication network, such as a wireless network, wherein a second portion of the software resides on the server and interfaces with the portion on the mobile device. Such a system permits immediate identification of plates anywhere in the workflow, including for example, identifying the location of plates in storage dedicated for reprint jobs. In an exemplary method, such as that depicted in FIG. 2A, reader 220, such as a mobile phone, may scan the code on the plate and then provide process parameter information to an operator, such as on the display 222 of the phone or on the display associated with a user interface corresponding to the process equipment (110, 120, etc.) relating to the current processing step. The operator may then enter the relevant process parameters into the process equipment for the next process step, if that equipment is not in communication with the scanning means to read process parameters automatically.

DEVICE MANAGER

One aspect of the Esko Persistent Marking Disclosures comprises controlling and coordinating the various process steps in a way that the overall process Is optimized in time and efficiency. Aspects of the claimed invention include not only providing process parameters to the processing machines (110, 120, etc.) for the various pre-press process stages in the workflow of making a flexo plate, but also providing real-time monitoring of the overall plate manufacturing process using readers 220 communicating the in-process locations of a plurality of plates in accordance with scans. Thus, a central tracking processor or "device manager" 170 may receive updates continuously during all process steps of the workflow and thus may be capable of providing a real-time plot of each plate's current position in the entire plate workflow. As used herein, the term "real-time" is intended to mean providing current information contemporaneously, subject to routine delays inherent in the communication protocols, processor speeds, and display rendering capabilities of the various components of the system. In some implementations, in addition to location information, process quality feedback may also be communicated to the Device Manager 170. The Device Manager 170 may be integrated into, for example, Automation Engine software from Esko, the Applicant of the present invention. Although certain specific workflow steps have been mentioned, it should be understood that the indicia may include information relating to other processing machines or process steps in addition to those described explicitly herein, and may, for example, cover any or all process steps between order intake at least until storage after printing or reprinting, which may be applicable for printers who make their own plates. The process is not limited to any number of steps, however, and thus in some embodiments, the process may cover fewer or more steps.

PRINTING STRUCTURES AT MULTIPLE ELEVATIONS

The bulk of the techniques as described in the Esko Persistent Marking Disclosures are for providing non-printing structures and printing structures at different elevations on the same plate. However, in some embodiments, there may be advantages to creating (such as by any of the methods known in the art or described herein) or introducing (such as by attaching a structure, including but not limited to structure made from the same or similar polymer as the plate, made externally by any process known in the art) printing (or condition printing) structures having different elevation levels on the same plate. By "conditional printing" is it meant that the structure, or parts of the structure, print only under certain conditions (such as, for example, after a predetermined amount of wear, or when printing with a predetermined amount of printing contact pressure (which may be greater than a normal amount of pressure).

One exemplary structure has a shape such as a stepped wall, with steps at different heights, or a sloped wall, or a registration or pressure mark. In some embodiments, this structure may be attached to (for example using an adhesive that is polymerized in a finishing step) the plate floor. In other embodiments, this structure may be created in or on the plate floor. Positioning of the structure does not necessarily require a high degree of accuracy. Externally-created (i.e. prefabricated) polymer structures that are attached to the plate after formation of the plate may be use for retrofitting pre-existing plates to add the structures for use for any purpose. In one embodiment, a floor-level attachment pad may be formed in the plate to indicate where the external structure is to be attached, and to provide an anchor point. The pad may include indicia (e.g. graphics, text, or a combination thereof) with information about the external structure to be attached, such as an identifier of a specific external structure (e.g. a serial number or other similar code) or type of external structure (e.g. a model number or other similar code), orienting information about how the external structure should be oriented on the pad, or a combination thereof. The anchor point / plate interface may have complex structural features (e.g. respective protrusions or indentations or peripheral bumps or detents that mate with one another) to create a strong bond and allow for a durable connection, which bond may be stronger than a bond achieved in the absence of such mating complex structural features. The corresponding mating features on the prefabricated structure / attachment pad interface may in some embodiments be configured to guide the prefabricated structure into alignment on the plate in only one or more preferred orientations, such as embodiments in which the features are asymmetrical (to promote a single orientation) or have symmetry relative to one direction, but not another (to promote orientations 180 degrees rotated from one another) or have a symmetry that promotes orientations in each of multiple rotated orientations (e.g. 0, 90, 180, and 270 degree rotations), but not in intermediate orientations. A curing step, such as back-illumination with UV, may be used to affix the externally-formed structure into place, by polymerizing the adhesive.

One application of such printing structures of different elevations include print control marks that indicate the print contact pressure of the press during printing. Print control marks for indicating print contact pressure produce different print results depending on the print contact pressure, which is adjustable between the print substrate cylinder and the cylinder carrying the photopolymer printing plate. This adjustment may be performed automatically using image recognition and software or by a press operator, who needs experience to assess the correct adjustment from looking at the running print substrate in the press using a stroboscope light. This task typically requires adjustment of the contact pressure on both sides of the printing cylinder. The pressure must be not too high or low and it has to be identical on both sides of the printing cylinder. The adjustment is performed by moving the axis of the printing cylinder closer or further away from the axis of the substrate cylinder, separately on the two extreme ends of the axis, as well as moving the anilox roller closer or further away from the axis of the printing cylinder. In embodiments of the invention, marks are provided across the area of the plate, and at least on both sides of the plate, thus making adjustment of the cylinder easier for operators, and offers an opportunity to enhance automated and online readjustments. Exemplary automated processes include those described in US Pat. Nos. 9,393,772 and 9,440,425, incorporated herein by reference, which describe printing a sequence of images and then analyzing those images using machine vision and software to determine the optimal pressure settings for anilox and plate, both for pressure and for register.

Another application for printing structures of different elevations is for optimization of different areas on the printing plate for different print applications, such as for the printing of solid colors versus artwork. While ink transfer for solid color works best with higher print contact pressure, artwork details like thin lines or screens benefit from lower print contact pressure for best print results.

One method to control the elevation level of polymer structures on the plate is to control the transmission of the UV light through the openings of the LAMs located on top of the polymer printing plate. Usually a flexographic photopolymer plate is exposed from the backside to form the floor and through a mask from the front side to form the structures that will stand up from the floor and form the printing relief of the plate. A mask opening is an area in the mask where a suitable amount of UV energy or any other actinic radiation energy can enter the photopolymer and cure portions of polymer from the plates top to the floor. Plate 1900 in FIG. 3 illustrates this situation. The grey structured areas represent the polymerized portions of the plate, including the plate floor 1902. Usually, the curing of the polymer starts at the top of the polymer layer directly under the openings in mask 1904 and propagates from that point to the deeper regions forming a truncated cone 1906. The shape of this cone (i.e. the steepness of the edges) is mainly determined by:

• the emission properties of the light source like emission angle range, intensity and wavelength; • the properties of the photopolymer; and

• the presence of oxygen in the polymer.

When the UV energy is not high enough, the polymerization of the cones may not reach the floor region such that the cones do not sufficiently bond, or do not bond at all, to the floor. In this case, the cones are removed in the following thermal or solvent development process step or will stay on the plate but tilt over to lie flat on the floor of the completely processed plate. FIG. 4 depicts a micrograph of a plate 2000 having such tilted cones 2002 among others still standing 2004. FIG. 5 depicts a portion of a plate 2100 with cones 2102 not attached to the floor.

While the actinic radiation may not be enough to cause polymerization of cones that are bonded to the floor, the combination of many mask openings may be sufficient to accumulate enough energy at the plate floor region to cause polymerization close to the plate floor. This is the underlying principle for the creation of structures of different height on a photopolymer printing plate in this application. This can be achieved by relatively high line count screens with relatively low percentage mask openings, but embodiments utilizing lower count screens are operable as well, as described further below. The invention is not limited to any particular combination of line count and percentage mask opening. The line count and percentage needed depend on the polymer type and thickness. Plate 2200 depicted in FIG. 6 illustrates the polymerization principle for this case, in which a plurality of openings 2202 in mask 2204 create overlapping cones that create structures 2206 bonded to the floor but having a height below the top of the plate. For a standard polymer (e.g. DuPont DPR), line counts of 170 LPI or higher and a mask opening percentage between 0.5% and 5 % are suitable to create polymerized structures in the plate that do not have individual screen pixels on top, but still produce an elevated plateau on the floor.

As noted above, various line counts for the same plate may be operable for implementing the concepts described herein and in the referenced applications for creating features below the top elevation of the plate, including some relatively low line counts (ranging from 211 to 61 LPI). Without being held to any particular theory of operation, the data indicates a possible a floor growth principle based on a constant light transmissivity for a targeted elevation level.

FIG. 10 depicts a graph showing parameters for creating a feature elevation of 0.21 mm above the floor on a TOP 045 plate using a squared pattern of mask openings arranged at a constant distance in a horizontal and a vertical direction, such as the pattern depicted in FIG. 11, which is an example of a pattern comprising 9-pixel mask openings spaced 19 pixels apart.

The circled points where the labeled lines cross the horizontal line show the combination of mask opening pixel clusters and their cluster distance that leads to an elevation of 0.21 mm. The labeling of the lines (e.g. "4 pixel") indicates the number of mask opening pixels in the cluster, and the horizontal axis denotes the cluster distance in pixels.

The circled line crossings corresponding to the following relationships set forth in TABLE 1.

TABLE 1

Thus, as a first approximation, a fixed ratio of approximately 200 (e.g.+/~ 10%) for the non-mask opening pixels per mask opening pixel result in the same elevation level independently from the number of mask opening pixels the clusters comprise. This ratio differs from one plate to another and also depends on the way the plate is UV exposed. Of course, only a limited range of pixel cluster sizes may be operable, because at a certain point, the cluster size will be big enough to grow printing structures to the plate's printing surface, and thus the ratio is not constant in the regime where the elevation level comes close to the printing surface.

CONTACT PRESSURE INDICATOR PLATE STRUCTURES Structures of different height levels may be arranged like a staircase at spots on the plate located in positions that will coincide with the left and right side of the printing roller when the plate is mounted in the printing press. The number of staircase steps that print reflect the amount of printing pressure applied, and if this pressure is identical on the left and right side of the printing roller and anilox.

The print result can be observed in the press during printing using High Speed Line Scan cameras. This online monitoring provides a convenient way for the press operator or for automated pressure setting software to adjust the contact pressure. FIGS. 7A and 7B shows a height profile of such a printing plate 2302 with a stack 2304 depicting corresponding print results at different contact pressures shown above the plate. The print marks located at the left 2310 and right 2312 side of the printed image 2314 depict how the contact pressure stays constant on the right (fixed) 2322 side of the printing roll 2320, but changes on the left (adjustable) side 2324 based upon adjustments.

Preferably the individual marks stand alone, and are not linked to one another, to avoid bending or tilting by neighboring marks that may already be in contact with the print substrate.

Control of contact pressure may be automated by means of digital image evaluation as described in US Pat Nos. 9,393,772 and 9,440,425, noted above. Such an arrangement may include a closed loop control, such that during press make- ready or whenever the image evaluation system detects a change in the number of print marks printing, it sends a signal to a subsystem of the press that controls the contact pressure, which causes actuators to change the contact pressure until the original number of print marks is detected again.

The same or similar structures as described above may also be used for registration of one print station to another (e.g. for different separations for a multi color image). Each printing separation may have register / pressure marks at different positions, to be monitored by the camera system. The position of the mark in the printing space will enable moving the decks into register, as described, for example, in U.S. Patent No. 9,393,772, incorporated herein by reference. Additionally, both register and pressure marks may be concealed by having a height that Is just under the regular print surface. In order to see them in the image, a slight addition of pressure is required between plate and substrate, for a brief moment during make-ready - sufficient in order for the camera system to see where each deck is printing. Once this has been observed, the pressure is reduced to the appropriate optimal printing pressure.

While differences in elevation may be implemented In any way described herein or known in the art, modifying back exposure intensity or duration of exposure to create elevations using back exposure processes and systems may be particularly well-suited for creating continuous raised floor areas from the back side, rather than raised floor areas comprising microdots created from the front side.

WEAR INDICATOR PLATE STRUCTURES

Printing marks located at an elevation below the top surface may also be used to indicate wear of the printing plate, and may typically be located in an area in which there is no expected print pattern in the design. When the plate surface wears down in the relevant area, the wear indicator structures will transfer ink to the substrate in that area in which no ink is expected to be visible. A structure that prints only after higher elevation structures degrade are generally referred to herein as a "second-tier printing structure" because such structures print only after a printing structure at a higher elevation experiences sufficient wear. Structures to be used for indicating contact pressure or wear may be generally referred to herein as "indicator structures," because they are intended to print only to indicate something, not as part of the artwork or solid rendition area intended to be printed by the plate. Such indicator structures that are intended to print only to indicate something can be distinguished from non-printing indicia that have an elevation much lower, at which they are intended not to print, and are for use in identifying the plate or workflow associated with the plate.

Exemplary wear indicator structures may include a stepped structure such as is depicted in FIGS. 7A and 7B, and the same structures may serve multiple purposes as contact pressure indicators (and/or register indicators) and wear indicators. When the printing plate has too much wear, more than the first step of the staircase may become visible already at the pressure corresponding to the print that appears with the lightest touch between printing cylinder and substrate cylinder at the point at which any reduction in contact pressure would cause some area of the design not to be printed. Such a print showing more marks than originally present at the beginning of the plate lifetime indicates that plate wear, typically meaning the plate may need to be replaced. In another embodiment, the wear indicator may comprise any geometric shape, such as for example, a slanted line without discrete steps.

An inline machine vision inspection system configured to detect the changes, and programmed with the location and structure of the wear indicator, may be configured to translate the length of the printed line or step into depth of wear.

Both slanted line and step structures are capable of providing quantified wear data to give early notice for when a plate may need to be changed. Notably, step structures may be distributed in any arrangement, and need not be aligned adjacent to one another in a staircase fashion, although a traditional staircase arrangement may be easiest to detect as a line in the image,

Providing wear indicator structures in the printing plate may also be used to generate a machine-readable pattern or code when the structures appear on the printed substrate. In this embodiment, the structures may be integrated within the printed design. The code may be designed to produce such a small change in the appearance of the printed image, so as to be indistinguishable by the human eye, but detectable and capable of interpretation by an inline inspection system, to provide early warning that the plate is wearing.

Methods of providing second-tier printing structures may also be used as a method for extending the lifetime of the plate, by "replacing" worn-out first-tier pixels with replacement second-tier pixels in the print, as wear ensues. For example, the use of different elevation structures may be used for extending the readability of embedded printed watermarks (wherein the term "printed watermark" is used here to refer to lightly printed matter on a substrate, not the "non-printing watermark indicia" as described elsewhere herein). Such printed watermarks are based on very small changes to the design, and thus are sensitive to small degradations in the printing plate. Sub-uppermost-surface pixels may form a second-tier printed watermark, to replace the original printed watermark formed by first-tier pixels as the first-tier pixels degenerate. Such changes may result in the print design still being of acceptable quality overall for the end customer, despite the minor changes in the characteristics of the printed watermark over time. Such changes may provide an early warning of degradation of the plate prior to that degradation reaching a point at which the quality is unacceptable.

Creation of the staircase print or sloped line marks in the plate is not limited to UV front exposure through different degrees of mask opening, but may be achieved by exposure from the rear side of the photopolymer plate. In this case, UV exposure is applied additionally to the normal UV back exposure that forms the plate floor, such as may be executed by an UV LED matrix as described in U.S. Published Application No. US20200016916. For use in the present embodiment, the LED matrix is configured to create different intensity levels in different sections of the matrix. For example, for a light source Is divided Into ten sections, the Intensity of the first section may have a maximum intensity, the second section 90% of the maximum intensity, and each of the following sections an intensity decreased by another 10%. Use of a gradient in intensity rather that step changes will produce a sloped line rather than discrete steps.

In another implementation, light of a LED UV light source having constant intensity may be directed to locations in the plate where print marks are desired through a film having different sections of neutral density for the UV light. The UV transmission of the different sections can range for example from 100% to 10 % in 10 % steps, resulting in ten marks between plate top surface and floor. Intensity and or exposure time may be adjusted such that the 100% mark reaches exactly the plate surface. Again, use of a gradient in the film neutral density will result in creation of a sloped line rather than discrete steps.

FIG. 8 shows a UV light source 2400 with ten segments 2401 to 2410 disposed relative to a portion of a polymer plate floor 2420 with print contact pressure marks raising up from the floor cured by the light source. Each of the segments of the light source delivers a different curing energy. For example, section 2401 delivers 100% of maximum (resulting in raised area 2421 on the plate), section 2402 delivers 90% of maximum, and so on, such that section 2410 (resulting in raised area 2430 on the plate) has only 10% of the total curing energy corresponding to section 2401. To obtain the different curing exposures, a single light source 2440 may have a homogenous intensity distribution across all of the fields with a film 2450 disposed between the source and the plate and having different transmissivities (and thus different amounts of intensity reduction) corresponding to each section. Achieving homogenous intensity across a given area may be provided by various known methods, such as using a kaleidoscope optic, as taught in US8578854, or by using an array of LEDs that have been compensated for homogeneity using a controller. In another embodiment, an array of otherwise identical LEDs may be controlled via exposure time or intensity to create the differences in exposure.

In one embodiment the UV Light source 2400, the electronics 2460 to control exposure time and intensity, and (in embodiments using such a method, the optional film 2450 for intensity reduction) may be combined in a handheld device with a trigger switch 2470 that allows an operator to place the marks after the conventional front and rear side exposure has been applied to the plate. Having a single device source to place all print contact pressure marks makes sure all marks have identical properties. Instead of manually placing the marks with a handheld device, the marks may also be placed by a XY gantry unit e.g. implemented in the UV exposure unit for main and rear side exposure. Because these marks may be created outside of the normal imaging process, the marks may be continuous in nature, rather than pixelated. Using a handheld device for applying the indicator structures may be best suited for use from rear side of a plate, although the invention is not limited thereto. Some embodiments may be suitable for rear or front use, whereas others may be suitable for use on only one or the other.

The range of UV exposure time and intensity are preselected according to the polymer plate type and thickness. For relatively thicker plates, exposure time and/or intensity will be relatively higher to grow the 100% mark to the very top surface. Although it is preferred that exactly one segment - the 100% segment - creates the mark that reaches the plate's top surface, the intensity may be chosen in a way that also the second mark receives enough exposure energy to reach the top. This compensates tolerances of the UV absorption of the dimensional stable layer under the floor of the polymer plate, which may vary from one plate batch to another. Having two or more samples receive calculated energy to reach the top makes sure that at least one grows up to the top surface.

Creation of the staircase print or sloped line marks in the plate, as well as other 2^nd tier structures Is not limited to techniques for exposure of the plate, but may be achieved by gluing/mounting/connecting pre-fa bricated features to the floor of the plate, after the plate is fully processed or during processing. Such pre-fabricated parts may be manufactured from the same polymers of which the plate is composed, or any other plastic or other material that interacts to ink and substrate similarly to the plate polymer. This will allow such structures to have very accurate dimensions, and thus provide a high degree of precision to the related actions, such as setting pressure or identifying wear.

Printing structures with different height levels for different print applications

Another aspect of this invention is the creation of printing structures having different height levels on the same plate to improve the printing of different print details on the plate. Packaging print applications typically present two different use cases: (1) covering big solid areas completely with ink (e.g. for background using spot color), and (2) printing of images containing text or pictures by using screen or linework (e.g. with process colors). As is understood in the art, "process colors" typically refer to Cyan, Magenta, Yellow and Black, whereas "spot colors" refer to other (e.g. Pantone®) colors used on the press. The differentiation between plates or portions thereof relevant to this aspect of the invention relate to plates or portions thereof that print mainly solids (with relatively higher total ink coverage) and plates or portions thereof that have screens/linework/smaller solid blocks on it (with relatively lesser total ink coverage). In practice, both types of features are printed in all colors (spot colors and process colors), so the invention is not limited to use of any specific type of the ink with respect to any type of plate or portion thereof. Thus, we refer to "relatively high ink coverage" and "relatively low ink coverage" plates or plate areas when referring to these different plates or portions thereof, to denote that the relatively high ink coverage plates or plate areas generally receive and print more ink per unit area than the relatively low ink coverage plates or plate areas.

For relatively high ink coverage plates, the printer often applies as much print pressure as possible in order to smudge the ink in a closed film, without gaps or pinholes, onto the print substrate. This is, for example, required for background or brand colors that may be later over-printed with other images like text or pictures.

For relatively low ink coverage plates, fine details are primarily printed. Too much pressure causes fine lines or screen dots to broaden or even bend over. The contact pressure is therefore not adjusted as high for relatively low ink coverage plates as for relatively high ink coverage plates. To reduce the number of printing drums for a multicolor print job and save costs, solid areas and fine printing details of the same color are often combined on the same printing plate, allowing only a compromise for contact pressure between the two use cases.

To overcome this problem, printing plates may be created with different height levels for the two use cases, with solid (relatively high ink coverage) areas exposed to a height level up to the top of the plate, while fine linework and screen details (relatively low ink coverage areas) located slightly below the top level. FIG. 9 shows the profile of cured polymer 2510 for such a plate. The line 2501 indicates the top level to which solid area printing structures are elevated. Line 2502 indicates the level of elevation to which printing structures for printing details like screens or linework, are elevated. Line 2503 indicates non-printing indicia, such as are described in more detail above and in the applications incorporated herein by reference.

The creation of different height levels in the polymer printing plate by changing the number and size of mask openings per area unit may typically be limited to relatively larger details, because relatively smaller details may not cover enough area on the LAMs to grow structures from the floor. Moreover, it is generally more difficult to create small height level differences close to the top of the plate for fine details; thus, the growth of structures by modification of the number and size of the mask openings is generally limited to coarse printing structures. Accordingly, a different approach is preferred for producing plates with height level differences between the printing structures used for printing relatively high ink coverage vs. relatively high ink coverage areas.

One method for creating small differences is to modify the stain level of the ablated areas. Stain level is the measure for effectiveness of mask removal by the laser beam ablation. For a good laser ablated surface on a LAM (mask opening), the density reading of the stain level is around 0.02 - 0.03 as compared to a plate with no mask, which means 93-95 % of the incoming UV light reaches the polymer, with 5-7% blocked by remaining dust from the ablated mask. The density reading D is calculated by D = - log(T/100), whereas T is the light transmissibility in %.

Normally it is desired to remove the mask most perfectly to allow as many UV photons to enter the polymer through the mask openings as possible. When the laser power is too low, the resulting stain level may be relatively higher than normal. For example, a density of 0.07 may still be acceptable, but may block 15% of the incoming UV light.

It is well known in the art of photopolymer printing plate making that oxygen in the plate and the air surrounding the plate acts as an inhibitor for the polymerization process. As discussed in US Pat. No. 8,227,769, incorporated herein by reference, flat top dots form, in part, because high UV intensities cause polymerization to the very top of the plate by speeding up the polymerization process versus oxygen inhibition. In contrast, lower UV intensities cause round top structures that do not grow to the original top of the non-polymerized plate, because oxygen blocks polymerization into the top regions of the plate.

A height difference on a photopolymer printing plate between areas holding structures to print with relatively high ink coverage and areas dedicated to print with relatively low ink coverage may be created by ablating the image portions for process colors with higher stain level than the image portions for relatively high ink coverage areas. Relatively high ink coverage areas are often printed using surfaces with microstructures. Microstructures improve ink splitting and create a homogenous ink film on the print substrate. Single pixel screens may be imaged to create these microstructures, such as are described in U.S. Published Patent Application No. US20190315141, incorporated herein by reference.

Single pixels are difficult to image because they stand alone separated from other image pixels, and there is no synergy effect for the mask opening as for a cluster of many connected pixels imaged into the LAM. That is why ESKO CDI imagers boost the laser power for single pixels by a factor of 2 to 5 compared to the power for normal image pixels. To decide whether to boost or not, the imager has a detector that scans the image data during imaging and identifies single pixels in the image file. Whenever a single pixel is detected, the laser power is increased to a level higher than the level for normal connected image pixels. Therefor ESKO CDI imagers have the ability to produce two different intensity levels. The UV exposure intensity is set to a level that will produce flat top structures for mask openings consisting of boosted single pixels - which means the singe pixel structures and thus the relatively high ink coverage areas are elevated to the very top surface of the plate.

Mask openings not boosted during imaging block more UV light because of their higher stain level. Because of the reduced UV intensity, the growth of polymer printing structures is hindered by oxygen inhibition, which prevents a growth of these structures to the very top of the plate. The stain level allows control of how much the light intensity is reduced; thus, control of stain levels also offers an ability to control the height level of the polymer structures.

The UV intensity may be carefully selected to avoid an overly high intensity that would cure unwanted flat tops from a mask opening having the higher stain level. The invention is not limited, however, to any particular range of UV intensities or resulting combinations of flat top and round top dots at any particular elevation.

The foregoing method for creating different intensity levels is not limited to the principle described above, nor is it limited to two intensity levels, nor is it limited to the creation of relatively high ink coverage and relatively low ink coverage elevations (e.g. the intensities may approach a gradient in intensity levels for creating sloped features such as a sloped line wear indicator). The image file may as well contain 3-dimensional information (e.g. each pixel in the image File may have depth information that is transferred into a laser ablation energy for this pixel) in addition to location information for each pixel.

The following method may be applied to create a flexographic photopolymer printing piate with different height levels for relatively high and relatively low ink coverage areas:

1. Identify portions in an image file that are populated by relatively high ink coverage areas (including but not limited to spot colors areas) and portions belonging to relatively low ink coverage areas (including but not limited to process color areas.

2. Mark the portions of the image file belonging to relatively high ink coverage areas differently than those belonging to relatively low ink coverage areas.

3. Send the image file to an imager that can identify the different markings in the file and dedicate different laser power intensities to the differently marked portions of the image file

4. Image the differently marked portions of the image file with different intensities, causing different stain levels for the different portions of the image. 5. Expose the photopoiymer plate with UV light of an intensity high enough to cure flat top dot structures for the plate areas having the lowest stain level and low enough to cure round top dot structures for the plate areas having higher stain levels.

Stain level modification may also be applied to create the print contact pressure marks, wear indictors, or other second-tier printing structures as discussed above, as well as any types of different printing elevation features, regardless of purpose for their use. Plates may comprise any number of features having different elevations, including but not limited to: non-prlntlng indicia at a non-printing elevation, printing structures at a top elevation corresponding to relatively high ink coverage areas, printing structures at an elevation below the topmost elevation corresponding to relatively low ink coverage areas, one or more second-tier printing structures intended to print only upon degradation of adjacent higher-elevated printing structures, and contact pressure printing structures having a plurality of different elevations that may or may not print, based upon the amount of pressure applied.

Printing Tool Lifetime Tracking and Prediction

As noted in the background section of the application, there is a need for better systems and method for predicting when a printing tool or tooling should be replaced. As used herein, the terms "tool" or "tooling" may be used interchangeably, with no specific implication intended by the use of one instead of the other. One aspect of the invention includes methods and systems to enable printers to automatically monitor the actual usage of these tools, identify and measure degradation in the tools, plan usage of tools in a way that extends their lifetime, and also to predict the expected end of life of a tool. These together may reduce the cost of expendables in the print process.

One method for measuring and recording lifetime is to track the actual meters printed using the tool, but this does not include any quality information. Such meter counting can be achieved by connecting a processing unit to a printing press shaft encoder, applying a rotary encoder to the printed web, or using a non-contact velocity measurement, for example, based on a laser and optics. A more advanced method may include an Image Quality Metric to quantify the printed image quality, and an inline inspection system may periodically calculate the metric and any trend in the metric over time. Such an inline inspection system may detect defects in the printed image and perform a root cause analysis to identify the tool related to the defect, such as a printing plate or anilox, for example. Automatic or manual investigation may show precisely which tool from which printing deck contributed to the defect or to the degradation in the metric, and action may be taken to record the information in the tool database, or replace the tool. In some cases, such as with anilox, the tool may be used again by allocating it to a color deck in which the print design does not have any print details in the vicinity of the defective area. When such capability is available, it is possible to plan to optimize use of anilox rollers, allocating the best fit of existing rollers to the upcoming print jobs In the production schedule, to maximize re-use of damaged anilox rollers. This is not possible in current workflows, as no record is available of defects, and anilox rollers are typically not uniquely identifiable and historically have not been identified in practice. Notably, however, at least some of the same methods as described herein and in connection with referenced applications and patents in connection with providing ID information on a printing plate may be applicable for providing an ID on an anilox roller in a manner that does not interfere with ink transfer,

A direct result of being able to make and record such measurements is the ability to analyze the recorded data and find patterns that can help improve the lifetime of the tools, as well as calculate a performance baseline for a given tool on a given press, against which a specific tool, or a specific press machine, may be compared. Such analysis can help printers improve their processes and equipment utilization, giving additional benefit. An additional benefit is to map tools to print jobs in a way that maximizes the utilization of the tools.

Predicting the lifetime of a specific tool enables long-run jobs to be printed with confidence without prophylactically making new tools, and to wait for notifications from the inline inspection system on when to prepare a new tool. Such a solution may notify the operator that, e.g., the plate on deck #3 needs to be replaced in 1 hour or 15,000 meters, and deck #6 in 2 hours, enabling just-in-time plate manufacturing.

In a preferred embodiment, a unique ID code is attached to each tool, in way that can be read by systems along the workflow, such as described herein above with respect to providing unique non-printing indicia on the printing plate. The non-printing indicia as described herein above does not print, because it is below the surface, but it may be machine readable, and this information plus the printing system (deck) number is provided to the inline inspection system. This system can load the already recorded history of the plate, and continue to u date it as printing proceeds. An alternative to reading the non-printing indicia on the plate with a machine is for the printing press to provide some amount of over-pressure for a short duration (e.g. one or 2 rotations of the printing plate) sufficient to obtain a transient image of the code onto the substrate, but not enough to create damage to the plate. An inspection system may be configured to instruct the press to perform such an action, and thus be ready to pick up and read the code. Such an action may be integrated into the make-ready phase of the print job, where pressure is applied in some range of pressure, and thus not require special or additional waste. In this embodiment, therefore, the non-printing indicia may be at an elevation substantially above the floor that it does not print under normal pressure, but can be forced to print under non-routine contact pressures.

Thus, one aspect of the invention includes using unique identifiers, such as the indicia as described herein for plates, for tracking (a) use metrics (e.g. meters of substrate printed), and (b) working combinations (e.g. use of plate A with anilox B applying ink C for printing D meters on substrate E using printing line F). Thus, in addition to providing machine-readable unique identifying indicia on a printing plate, aspects of the invention may include utilizing machine readable unique identifying indicia on other printing tools as well, such as on anilox rollers. Identifiers may be provided on all types of equipment that permit operators to quickly compile information, such as with a handheld scanner, for entry of information into a tracking system . The scanner may use pre-existing information for some of the data entry (e.g. a code such as a QR code, barcode, serial number, model number, or the like, may already be present on an ink container; a faceplate may already be present on a particular piece of equipment).

Detecting Quality degradation of printing Plates

Various approaches are possible for quantifying the degradation of a printing plate. AVT provides a software feature called JobRef, which compares an actual print to the pdf design file. This is activated at the start of a print job, such that if a plate has noticeable damage, it is found by the software. One method to monitor image quality continuously is to activate JobRef periodically during print production, and following the gradual increase in the differences between the design and the print. Another method is to define an image quality metric, such as is known in the art and described in U.S. published patent application US20190240971A1 relating to color control in flexographic printing. A threshold may be set to notify that the metric has passed from acceptable to borderline and from borderline to unacceptable, for appropriate action at each milestone.

Yet another method involves the use of wear indicator structures in the printing plate, which structures cause visible printed marks only when the plate surface degrades sufficiently, as described in detail above. A machine vision system configured to detect the changes over time on the fly, may provide information that is stored in the tracking system for the plate over its lifetime, as well as information for sounding an alarm when a change has occurred that has sufficiently degraded quality of the print job to a point that replacement is recommended.

Plates, anilox and other tools suffer damage throughout the workflow - when moving from the tool-manufacturing area to the manufacturing facility; in all moves to and from storage; to, from and during cleaning, mounting and unmounting; and moving to and from printing presses. Damage created during printing may be found as mentioned above. Damage in other phases of work may be detected by JobRef when the print starts, and, along with tracked information about the tool history, may be analyzed to find the root cause. Accordingly, the processor associated with the tracking system may be programmed with instructions for operating an expert system that is capable of machine learning to not only detect, e.g,, what plate and anilox was damaged when it reached the press, but also suggest possible reasons for the damage and/or additional tools to check, based on the damage detected.

Application to other tools

It is known that the degradation of tools is dependent on the type of tool, the material it is made of, the tool manufacturing, cleaning and other manipulations, both from the process and equipment involved In that process, as well as the interaction of the tool with the press machine, inks, substrates and other chemicals that are applied to the tools. By collecting the information on the use of the tools, preferably together with information on ink, substrate and the like, during printing and during other steps in the production workflow, patterns may be detected that provide useful insights into the interactions as described. Such insights may lead to improved training for printers, better maintenance of presses, better matching of which jobs to print on which press with which tools, and the like. Such information is typically not collected and thus not routinely accessible or available today, and thus printers need to rely on their own experience, gut feeling, and information provided by the tool suppliers.

Although initially described herein with respect to providing a unique ID on a printing plate (by any number of methods), it should be understood that providing machine-readable unique ID information on other printing tools, such as in particular the anilox roller, a die cut tool or an ink jet module may permit collection of helpful data. Such machine-readable ID information may take the form of graphic codes (e.g. barcodes or QR codes), RFID tags, alphanumeric codes readable by a machine, or any means for providing unique identification to a tool known in the art,

ID information or tags may be printed or otherwise disposed on the tools directly or on substrates (e.g. labels or stickers) affixed to the tools, or may be embossed, engraved, or disposed on the tool in any way known in the art. Readers for detecting such indicia, including but not limited to machine vision systems comprising cameras and processors configured with suitable software, RFID readers, and the like, are well known in the art and are not detailed further herein. Aspects of the invention are not limited to any particular method of marking and reading ID information on the printing tools.

Data collection coupled with machine vision inspection for wear and tear may permit predictive monitoring based upon numerous variables in the use history of the tool, and may lead to earlier and/or more efficient detection of problems and replacement of worn tooling. For example, data accumulated corresponding to actual failures may be used or providing predictive maintenance recommendations prior to future failures occurring. The machine learning tool may be implemented on a computer processor accessible via a global communication network, such that information relating to usage may be collected from a plurality of locations. For example, the machine learning may be used not only for applying historical data collected from a specific printing shop having a specific printing workflow in a specific location, but also data collected from a plurality of printing shops having a plurality of workflows in a plurality of locations. Such information may also be able to pinpoint differences in wear experienced by workflows in a different location, which differences may be analyzed to recommend better practices for the faster wear workflow, or may be used for commissioning further study and data collection to facilitate future such recommendations. The workflows in different locations may be workflows operated by a same entity, or by different entities with other commonalities, such as common process equipment provided by a single vendor. Equipment vendors may be able to show value of their equipment over those of competitors and/or improve their products based upon actual collected data, or may be able to use the provision of the value-added service of providing tracking and predictive monitoring for its equipment as a competitive advantage over vendors without the capability of performing similar tracking and predictive monitoring.

The various systems and methods as described herein in the various sections may be implemented independently, or together as part of a comprehensive system. For example, any of the types of indicia as described herein may be used to mark printing plates or other tools, including indicia that has embedded information embodying an address or other information that can be used to generate a unique address accessible via a network (e.g. an address in the cloud) where information is stored. The information may include operating information (e.g. control settings), identification information, tracking information, or any of the information as discussed herein. In particular, plates may comprise wear indicators as described herein, and information obtained from reading those wear indicators may also be stored in the information about the plate. The ID information about the plate and the workflow may be read at any time along the plate workflow, including white a plate is on the press or when the plate is in on an off- press station. Information useful for selecting pressure and register settings on the press may be included in the stored information, and the information regarding pressure and register settings may be adjusted dynamically based upon information determined by reading indicators, such as but not limited to wear indicators. The printing station may be configured to periodically scan the plates and check for deterioration even while the plate is actively being used for printing, including but not limited to reading embedded wear marks as described herein.

It should be understood that each part of the invention here may stand alone without being practiced in conjunction with other parts. For example, plates without indicators of any kind (or the prints created thereby) can be scanned for deterioration of the plate, or defects in settings, using machine vision systems, as are known in the art. Information gleaned from such scans may be associated with the plate (or other tool) by updating to the database identified by the unique indicia associated with the plate or tooling. Processors, including but not limited to machine learning algorithms or expert systems, may then evaluate the collective information and output a reaction based upon that evaluation. The reaction may include adjusting a setting or a recommended setting associated with the plate or other tool, predicting a future action (such as when a part may need to be replaced), or providing a prompt to a human operator responsible for a portion of the printing workflow. Such a prompt may include, but is not limited to, a warning that a part may need to be replaced immediately, a setting changed, or an anomaly further investigated or at least acknowledged by the human operator, before proceeding or continuing to print using a plate or tools that may produce unusable quality prints. The warnings may pertain to the portion of the workflow where the information is detected, or may pertain to another portion of the workflow. For example, as discussed herein, an expert system may diagnose that one or more observations in a first portion of the workflow has a root cause in a second portion of the workflow that may require a change, or at least inspection, of the second portion of the workflow to improve quality overall in the workflow. Although certain aspects of the invention are particularly useful and advantageous in a flexo environment, the disclosure herein is not limited to any particular type of printing tools, printing plates or processing techniques.

Although the Invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. Further and/or other aspects and embodiments of the disclosure are disclosed in the following items:

Item 1. A process for making a flexo plate, the process comprising providing a plurality of plate structures having a plurality of different elevations relative to the plate floor, including at least a first set of printing structures having a top elevation at a first level of the plate and at least a second set of printing structures having a top elevation at a second elevation above the plate floor below the first elevation but above the plate floor.

Item 2. The process of Item 1, wherein the first level comprises an uppermost level and wherein the second set of printing structures comprises an indicator structure having a plurality of elevations, including at least one elevation lower than the uppermost level and higher than the plate floor, wherein the conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure greater than an amount of contact pressure required for image printing.

Item 3. The process of Item 2, wherein the plate comprises a plurality of contact pressure indicator structures each having different elevations.

Item 4. The process of Item 2, wherein the one or more indicator structures comprises one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

Item 5. The process of Item 4, wherein the one or more second-tier structures comprise a wear indicator. Item 6. The process of Item 5, wherein the wear indicator comprises a plurality of steps at different elevations. Item 7. The process of Item 6, wherein the wear indicator comprises a sloped line sloping from a first end at a first elevation to a second end at a second elevation.

Item 8. The process of Item 5, wherein the wear indicator comprises a plurality of features that form a code.

Item 9. The process of Item 4, wherein the one or more first-tier structures form a printed watermark and the one or more second-tier structures comprise a replacement printed watermark.

Item 10. The process of any one of Items 2 - 9, wherein the one or more indicator structures are disposed on a prefabricated structure formed apart from the printing plate, the process further comprising attaching the prefabricated structure to the plate floor.

Item 11. The process of Item 10, comprising creating a floor-level attachment pad in the plate to receive the prefabricated structure. Item 12. The process of Item 11, comprising creating the floor-level attachment pad with informational indicia about the prefabricated structure to be received.

Item 13. The process of Item 12, wherein the informational indicia includes an identifier of a specific prefabricated structure or type of prefabricated structure, an orientation of the prefabricated structure, or a combination thereof.

Item 14. The process of Item 11, wherein the floor-level attachment pad and the external structure have mating non-planar features at an interface between the attachment pad and the external structure.

Item 15. The process of Item 14, wherein the mating non-planar features strengthen anchoring of the prefabricated structure to the attachment pad relative to an interface without such features, provide orientation of the prefabricated structure on the attachment pad, or a combination thereof. Item 16. The process of any one of Items 10-15, comprising attaching the prefabricated structure to the floor with a curable adhesive, and then performing a curing step to affix the prefabricated structure to the plate by polymerizing the adhesive. Item 17. The process of any one of Items 3 -9, comprising creating the one or more indicator structures from a back side of the plate.

Item 18. The process of any one of Items 3-9 comprising creating the different elevations of the plurality of plate structures by providing correspondingly different stain levels on a LAM layer of the plate. Item 19. The process of Item 18, comprising performing a single imaging step on a single LAM to create the different elevations of the plurality of plate structures.

Item 20. The process of Item 19, comprising performing a single UV exposure process, the single UV exposure process having one or more exposure steps. Item 21. The process of Item 20, further comprising providing image information to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for imaging that pixel.

Item 22. The process of Items 3-9, wherein the step of creating the different elevations of the plurality of plate structures comprises exposing the plate with respective different energy levels of actinic radiation.

Item 23. The process of Items 22, comprising providing the different energy levels using an UV LED exposure unit configured to produce the respective different energy levels. Item 24. The process of Item 23, wherein the UV exposure unit is configured to move relative to the plate. Item 25. The process of Item 22, comprising providing the different energy levels by interposing a film having respective different levels of transmissivity between an actinic radiation source and the plate.

Item 26. The process of Item 25, comprising providing the film and the actinic radiation source in a handheld unit having a switch for triggering emission of the actinic radiation through the film onto the plate.

Item 27. The process of Item 1, wherein the first set of printing structures correspond to relatively high ink coverage areas and the second set of printing structures correspond to relatively low ink coverage areas. Item 28. The process of Item 27, wherein the first elevation is at an uppermost level of the plate.

Item 29. The process of any one of Items 1, 27 or 28, comprising providing correspondingly different stain levels on a LAM layer of the plate to create the different elevations of the first elevation and the second elevation. Item 30. The process of Item 29, comprising performing a single imaging step on a single LAM to create the different elevations of the first elevation and the second elevation.

Item 31. The process of Item 30, comprising performing a single UV exposure process, the single UV exposure process having one or more exposure steps. Item 32. The process of Item 30, further comprising providing image information to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for imaging that pixel.

Item 33, A flexo plate product produced by the process of any one of Items 27 - 32.

Item 34. A flexo plate having a plurality of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising a first set of printing structures having a top elevation at a first elevation above the plate floor corresponding to relatively high ink coverage areas and a second set of printing structures having a top elevation at a second elevation below the first elevation but above the plate floor corresponding to relatively low ink coverage areas.

Item 35. The flexo plate of Item 34, wherein the first elevation is at an uppermost level of the plate.

Item 36. A flexo plate, the plate comprising: printing structures formed of cured photopolymer having a printing level above a floor of the plate and configured to print In a printing step of a plate workflow; and one or more indicator printing structures disposed at one or more elevations above the floor of the plate, but beneath a topmost level of the plate, and configured to print as an indicator of a condition of the printing plate or a printing system in which the plate Is mounted; the indicator printing structures comprising embossed, continuous features not defined by discrete microdots.

Item 37. A non-transitory computer readable storage medium having data stored therein including a first set of instructions for imaging a first plurality of printing dots defining a screened image for making routine printing structures on a flexographic printing plate via exposure to actinic radiation from a front side of the printing plate and a second set of instructions for imaging one or more indicator printing structures via exposure to actinic radiation, the indicator printing structures defining a line or series of steps extending from a first elevation to a second elevation.

Item 38. A flexo plate product produced by the process of any one of Items 1 - 26.

Item 39. A flexo plate having a plurality of types of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising printing structures having an elevation at an uppermost level of the plate and at least one conditional printing structure comprising an indicator structure having a plurality of elevations, including at least one elevation lower than the uppermost level and higher than the plate floor, wherein the conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure in excess of a predetermined threshold.

Item 40. The flexo plate of Item 39, wherein the at least one indicator structure includes a plurality of contact pressure indicator structures each having different height levels.

Item 41. The flexo plate of Item 39, wherein at least one indicator structure includes one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

Item 42. The flexo plate of Item 41, wherein the one or more second-tier structures comprise a wear indicator.

Item 43. The flexo plate of Item 42, wherein the wear indicator comprises a plurality of steps at different elevations.

Item 44. The flexo plate of Item 42, wherein the wear indicator comprises a sloped line sloping from a first end at a first elevation to a second end at a second elevation.

Item 45. The flexo plate of Item 42, wherein the wear indicator comprises a plurality of features that form a code.

Item 46. The flexo plate of Item 45, wherein the one or more first-tier structures form a printed watermark and the one or more second-tier structures comprise a replacement printed watermark.

Item 47. A system for detecting wear of a flexo plate, the system comprising: one or more wear indicator structures having at least a portion at an elevation not intended to print unless adjacent printing structures or an adjacent portion at a higher elevation experience a loss of elevation.

Item 48. The system of Item 47, further comprising a machine vision system configured to detect printing of the wear indicator structures.

Item 49. A system for tracking printing system metrics, the system comprising: the printing plate of Item 39; a reader configured to read the machine-readable unique identifier; a database stored in computer memory comprising a record associated with each printing system tool; a machine vision system for detecting a printed shape printed by the printing system on a substrate, the printed shape corresponding to the at least one indicator structure; and a processor connected to the reader and configured to evaluate a property of the printing plate based upon the printed shape on the substrate.

Item 50. The system of Item 49, wherein the printed shape is not detectable by a human naked eye.

Item 51. A handholdable device for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation, the handholdable device comprising a source of the actinic radiation configured to emit a predetermined dose of actinic radiation energy per unit time; a film with a plurality of regions, each region having a different transmissivity of the actinic radiation energy calculated to transmit an amount of actinic radiation energy required to cure a photopolymer plate to one of the respective plate elevations when exposed to the predetermined dose of actinic radiation for a predetermined amount of time; and a trigger for causing the source to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time. Item 52. A process for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation, the process comprising: providing the handholdable device of Item 51; disposing the handholdable device adjacent a surface of the photopolymer printing plate; and actuating the trigger to cause the device to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time.

Item 53. The method of Item 52, comprising disposing the handholdable device adjacent a back surface of the photopolymer printing plate when actuating the trigger.

Item 54. The method of Item 52, comprising disposing the handholdable device adjacent a front surface of the photopolymer printing plate when actuating the trigger.

Item 55. The method of Item 52, wherein the one or more indicator structures comprise continuous, non-pixelated structures.

Item 60. A system for imaging a laser ablatable mask (LAM), the system comprising: an imager comprising a laser configured to emit a beam in a path with an amount of energy operable to ablate at least a desired percentage of the LAM in the path; a processor configured to control the imager based upon pixel-based imaging information; and a computer memory, accessible to the processor, configured to store the imaging information, wherein the imaging information includes information identifying a location corresponding to each pixel and the amount of energy to be applied to ablate the mask in the location corresponding to the pixel, the system is configured to image the LAM to create different stain levels, including a first stain level corresponding to a first plurality of plate structures having a first elevation above a floor of the plate and a second stain level corresponding to a second plurality of plate structures having a second elevation at a level below the first elevation but above the plate floor.

Item 61. The flexo plate of Item 60, wherein the first elevation is at an uppermost level of the plate.

Item 62. The flexo plate of Items 60 or 61, wherein the second elevation is a non-printing elevation.

Item 63. The flexo plate of Items 60 or 61, wherein the second plurality of plate structures comprise conditional printing structures.

Item 64. The flexo plate of Item 63, wherein the conditional printing structures include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

Item 65. The flexo plate of Item 64, wherein the one or more first-tier structures form a watermark and the one or more second-tier structures comprise a replacement watermark.

Item 66. The flexo plate of Item 64, wherein the conditional printing structures define a plurality of elevations below the first elevation and above the plate floor. Item 67. The flexo plate of Item 66, wherein the plurality of elevations comprise a plurality of steps at different elevations.

Item 18. The flexo plate of Item 16, wherein the plurality of elevations define a sloped line.

Item 69. The flexo plate of Item 64, wherein the conditional printing structures comprise an indicator.

Item 70. The flexo plate of Item 69, wherein the indicator comprises a wear indicator.

Item 71. The flexo plate of Item 70, wherein the wear indicator comprises a plurality of features that form a code.

Item 72. The flexo plate of Items 70 or 71, wherein the first plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas and the second plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas.

Item 73. A non-transitory computer readable storage medium having machine-readable instructions stored therein for causing a processor to image a laser ablated mask (LAM) on a photopolymer printing plate, the instructions causing the processor to: access a computer memory storing the imaging information that includes information identifying a location corresponding to each of a plurality of pixels and an amount of laser energy to be applied to an abatable mask in each location corresponding to the pixel, wherein at least some of the plurality of pixels Include information identifying a different amount of laser energy than at least some of the others of the plurality of pixels, each different amount of laser energy corresponding to a different percentage of stain level remaining on the LAM; and control an imaging laser to emit a beam corresponding to the identified amount of energy in the identified location for each pixel, the identified amount of laser ablation energy operable to ablate at least a desired percentage of the LAM in the path; wherein the different percentages of stain levels remaining on the LAM correspond to stain levels that when the plate is exposed to actinic radiation through the mask, cause formation of a plurality of plate structures including a first set of plate structures having a top elevation at a first elevation above the plate floor and a second plurality of printing structures having a top elevation at a level below the first elevation but above the plate floor.

Item 74. The non-transitory computer readable storage medium of Item 73, wherein the first elevation is at an uppermost level of the plate.

Item 75. The non-transitory computer readable storage medium of Items 73 or 74, wherein the second elevation is a non-printing elevation.

Item 76. The non-transitory computer readable storage medium of Items 73 or 74, wherein the second plurality of plate structures comprise conditional printing structures.

Item 77. The non-transitory computer readable storage medium of Item

76, wherein the conditional printing structures include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

Item 78. The non-transitory computer readable storage medium of Item

77, wherein the one or more first-tier structures form a watermark and the one or more second-tier structures comprise a replacement watermark.

Item 79. The non-transitory computer readable storage medium of Item 77, wherein the conditional printing structures define a plurality of elevations below the first elevation and above the plate floor. Item 80. The non-transitory computer readable storage medium of Item 79, wherein the plurality of elevations comprise a plurality of steps at different elevations.

Item 81. The non-transitory computer readable storage medium of Item 80, wherein the plurality of elevations define a sloped line.

Item 82. The non-transitory computer readable storage medium of Item 77, wherein the conditional printing structures comprise an indicator.

Item 83. The non-transitory computer readable storage medium of Item

82, wherein the indicator comprises a wear indicator. Item 84. The non-transitory computer readable storage medium of Item

83, wherein the wear indicator comprises a plurality of features that form a code.

Item 85. The non-transitory computer readable storage medium of Items 83 or 84, wherein the first plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas and the second plurality of plate structures comprise printing structures corresponding to relatively low ink coverage areas.

Claims

1 . A process for making a flexo plate, the process comprising providing a plurality of plate structures having a plurality of different elevations relative to the plate floor, including at least a first set of printing structures having a top elevation at a first level of the plate and at least a second set of printing structures having a top eleva- tion at a second elevation above the plate floor below the first elevation but above the plate floor.

2. The process of claim 1 , wherein the first level comprises an uppermost level and wherein the second set of printing structures comprises one or more indicator structures having a plurality of elevations, including at least one elevation lower than the uppermost level and higher than the plate floor, wherein the conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure greater than an amount of contact pressure required for image printing.

3. The process of one of claims 1 to 2, wherein the plate comprises a plural- ity of contact pressure indicator structures each having different elevations.

4. The process of one of claims 2 to 3 when depending on at least claim 2, wherein the one or more indicator structures comprises one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

5. The process of claim 4, wherein the one or more second-tier structures comprise a wear indicator.

6. The process of claim 5, wherein the wear indicator comprises a plurality of steps at different elevations.

7. The process of one of claims 5 to 6, wherein the wear indicator comprises a sloped line sloping from a first end at a first elevation to a second end at a second elevation.

8. The process of one of claims 5 to 7, wherein the wear indicator comprises a plurality of features that form a code.

9. The process of one of claims 4 to 8, wherein the one or more first-tier structures form a printed watermark and the one or more second-tier structures comprise a replacement printed watermark.

10. The process of any one of claims 2 - 9 when depending on at least claim 2, wherein the one or more indicator structures are disposed on a prefabricated structure formed apart from the printing plate, the process further comprising attaching the prefabricated structure to the plate floor.

11. The process of claim 10, comprising creating a floor-level attachment pad in the plate to receive the prefabricated structure.

12. The process of claim 11 , comprising creating the floor-level attachment pad with informational indicia about the prefabricated structure to be received.

13. The process of claim 12, wherein the informational indicia includes an identifier of a specific prefabricated structure or type of prefabricated structure, an orientation of the prefabricated structure, or a combination thereof.

14. The process of one of claims 11 to 13, wherein the floor-level attachment pad and the external structure have mating non-planar features at an interface between the attachment pad and the external structure.

15. The process of claim 14, wherein the mating non-planar features strengthen anchoring of the prefabricated structure to the attachment pad relative to an interface without such features, provide orientation of the prefabricated structure on the attachment pad, or a combination thereof.

16. The process of any one of claims 10-15, comprising attaching the prefabricated structure to the floor with a curable adhesive, and then performing a curing step to affix the prefabricated structure to the plate by polymerizing the adhesive.

17. The process of any one of claims 2 -9 when depending on at least claim 2, comprising creating the one or more indicator structures from a back side of the plate.

18. The process of any one of claims 3-9 when depending on at least claim 3, comprising creating the different elevations of the plurality of plate structures by providing correspondingly different stain levels on a LAM layer of the plate.

19. The process of claim 18, comprising performing a single imaging step on a single LAM to create the different elevations of the plurality of plate structures.

20. The process of one of claims 18 to 19, comprising performing a single UV exposure process, the single UV exposure process having one or more exposure steps.

21. The process of one of claims 18 to 20, further comprising providing image information to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for imaging that pixel.

22. The process of one of claims 3-9 and 18 to 21 when depending on at least claim 3, wherein the step of creating the different elevations of the plurality of plate structures comprises exposing the plate with respective different energy levels of actinic radiation.

23. The process of claim 22, comprising providing the different energy levels using an UV LED exposure unit configured to produce the respective different energy levels.

24. The process of claim 23, wherein the UV exposure unit is configured to move relative to the plate.

25. The process of claim 22, comprising providing the different energy levels by interposing a film having respective different levels of transmissivity between an actinic radiation source and the plate.

26. The process of claim 25, comprising providing the film and the actinic radiation source in a handheld unit having a switch for triggering emission of the actinic radiation through the film onto the plate.

27. The process of one of claims 1 to 26, wherein the first set of printing structures correspond to relatively high ink coverage areas and the second set of printing structures correspond to relatively low ink coverage areas.

28. The process of one of claims 1 to 27, wherein the first elevation is at an uppermost level of the plate.

29. The process of any one of claims 1 to 28, comprising providing correspondingly different stain levels on a LAM layer of the plate to create the different elevations of the first elevation and the second elevation.

30. The process of claim 29, comprising performing a single imaging step on a single LAM to create the different elevations of the first elevation and the second elevation.

31. The process of claim 30, comprising performing a single UV exposure process, the single UV exposure process having one or more exposure steps.

32. The process of one of claims 29 to 31 , further comprising providing image information to an imager for ablating the LAM in the form of a plurality of pixels, each pixel having an ablation location and an ablation energy level corresponding to the stain level for imaging that pixel.

33. A non-transitory computer readable storage medium having instruction stored thereon that, when executed by a processor, cause the processor to perform the process according to one of claims 1 to 32.

34. A flexo plate product produced by the process of any one of claims 1 - 32.

35. A flexo plate having a plurality of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising a first set of printing structures having a top elevation at a first elevation above the plate floor corresponding to relatively high ink coverage areas and a second set of printing structures having a top elevation at a second elevation below the first elevation but above the plate floor corresponding to relatively low ink coverage areas.

36. The flexo plate of claim 35, wherein the first elevation is at an uppermost level of the plate.

37. A flexo plate, the plate comprising: printing structures formed of cured photopolymer having a printing level above a floor of the plate and configured to print in a printing step of a plate workflow; and one or more indicator printing structures disposed at one or more elevations above the floor of the plate, but beneath a topmost level of the plate, and configured to print as an indicator of a condition of the printing plate or a printing system in which the plate is mounted; the indicator printing structures comprising embossed, continuous features not defined by discrete microdots.

38. A non-transitory computer readable storage medium having data stored therein including a first set of instructions for imaging a first plurality of printing dots defining a screened image for making routine printing structures on a flexographic printing plate via exposure to actinic radiation from a front side of the printing plate and a second set of instructions for imaging one or more indicator printing structures via exposure to actinic radiation, the indicator printing structures defining a line or series of steps extending from a first elevation to a second elevation.

39. A flexo plate having a plurality of types of plate structures at a plurality of elevations relative to the plate floor, the plate structures comprising printing structures having an elevation at an uppermost level of the plate and at least one conditional printing structure comprising an indicator structure having a plurality of eleva- tions, including at least one elevation lower than the uppermost level and higher than the plate floor, wherein the conditional printing structure includes at least one elevation thereof configured to print conditionally after a predetermined amount of plate wear or upon application of printing contact pressure in excess of a predetermined threshold.

40. The flexo plate of claim 39, wherein the at least one indicator structure includes a plurality of contact pressure indicator structures each having different height levels.

41. The flexo plate of one of claims 39 to 40, wherein at least one indicator structure includes one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

42. The flexo plate of claim 41 , wherein the one or more second-tier structures comprise a wear indicator.

43. The flexo plate of claim 42, wherein the wear indicator comprises a plurality of steps at different elevations.

44. The flexo plate of claim 42, wherein the wear indicator comprises a sloped line sloping from a first end at a first elevation to a second end at a second elevation.

45. The flexo plate of one of claims 42 to 44, wherein the wear indicator comprises a plurality of features that form a code.

46. The flexo plate of one of claims 41 to 45, wherein the one or more first-tier structures form a printed watermark and the one or more second-tier structures comprise a replacement printed watermark.

47. A system for detecting wear of a flexo plate, the system comprising: one or more wear indicator structures having at least a portion at an elevation not intended to print unless adjacent printing structures or an adjacent portion at a higher elevation experience a loss of elevation.

48. The system of claim 47, further comprising a machine vision system configured to detect printing of the wear indicator structures.

49. A system for tracking printing system metrics, the system comprising: the flexo plate of one of claims 39 to 46; a reader configured to read the machine-readable unique identifier; a database stored in computer memory comprising a record associated with each printing system tool; a machine vision system for detecting a printed shape printed by the printing system on a substrate, the printed shape corresponding to the at least one indicator structure; and a processor connected to the reader and configured to evaluate a property of the printing plate based upon the printed shape on the substrate.

50. The system of claim 49, wherein the printed shape is not detectable by a human naked eye.

51. A handholdable device for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation, the handholdable device comprising a source of the actinic radiation configured to emit a predetermined dose of actinic radiation energy per unit time; a film with a plurality of regions, each region having a different transmissivity of the actinic radiation energy calculated to transmit an amount of actinic radiation energy required to cure a photopolymer plate to one of the respective plate elevations when exposed to the predetermined dose of actinic radiation for a predetermined amount of time; and a trigger for causing the source to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time.

52. A process for creating one or more indicator structures at different plate elevations on a photopolymer printing plate configured to be cured by actinic radiation, the process comprising: providing the handholdable device of claim 51 ; disposing the handholdable device adjacent a surface of the photopolymer printing plate; and actuating the trigger to cause the device to emit the predetermined dose of actinic radiation toward the film for the predetermined amount of time.

53. The process of claim 52, comprising disposing the handholdable device adjacent a back surface of the photopolymer printing plate when actuating the trigger.

54. The process of claim 52, comprising disposing the handholdable device adjacent a front surface of the photopolymer printing plate when actuating the trigger.

55. The process of one of claims 52 to 54, wherein the one or more indicator structures comprise continuous, non-pixelated structures.

56. A system for imaging a laser ablatable mask (LAM), the system comprising: an imager comprising a laser configured to emit a beam in a path with an amount of energy operable to ablate at least a desired percentage of the LAM in the path; a processor configured to control the imager based upon pixel-based imaging information; and a computer memory, accessible to the processor, configured to store the imaging information, wherein the imaging information includes information identifying a location corresponding to each pixel and the amount of energy to be applied to ablate the mask in the location corresponding to the pixel, the system is configured to image the LAM to create different stain levels, including a first stain level corresponding to a first plurality of plate structures having a first elevation above a floor of the plate and a second stain level corresponding to a second plurality of plate structures having a second elevation at a level below the first elevation but above the plate floor.

57. The system of claim 56, wherein the first elevation is at an uppermost level of the plate.

58. The system of claims 56 or 57, wherein the second elevation is a nonprinting elevation.

59. The system of claims 56 or 57, wherein the second plurality of plate structures comprise conditional printing structures.

60. The system of claim 59, wherein the conditional printing structures include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

61. The system of one of claims 59 to 60, wherein the one or more first-tier structures form a watermark and the one or more second-tier structures comprise a replacement watermark.

62. The system of one of claims 59 to 61 , wherein the conditional printing structures define a plurality of elevations below the first elevation and above the plate floor.

63. The system of claim 62, wherein the plurality of elevations comprise a plurality of steps at different elevations.

64. The system of claim 62, wherein the plurality of elevations define a sloped line.

65. The system of one of claims 59 to 64, wherein the conditional printing structures comprise an indicator.

66. The system of claim 65, wherein the indicator comprises a wear indicator.

67. The system of claim 66, wherein the wear indicator comprises a plurality of features that form a code.

68. The system of one of claims 56 to 67, wherein the first plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas and the second plurality of plate structures comprise printing structures corresponding to relatively low ink coverage areas.

69. A non-transitory computer readable storage medium having machine- readable instructions stored therein for causing a processor to image a laser ablated mask (LAM) on a photopolymer printing plate, the instructions causing the processor to: access a computer memory storing the imaging information that includes information identifying a location corresponding to each of a plurality of pixels and an amount of laser energy to be applied to an abatable mask in each location corresponding to the pixel, wherein at least some of the plurality of pixels include information identifying a different amount of laser energy than at least some of the others of the plurality of pixels, each different amount of laser energy corresponding to a different percentage of stain level remaining on the LAM; and control an imaging laser to emit a beam corresponding to the identified amount of energy in the identified location for each pixel, the identified amount of laser ablation energy operable to ablate at least a desired percentage of the LAM in the path; wherein the different percentages of stain levels remaining on the LAM correspond to stain levels that when the plate is exposed to actinic radiation through the mask, cause formation of a plurality of plate structures including a first set of plate structures having a top elevation at a first elevation above the plate floor and a second plurality of printing structures having a top elevation at a level below the first elevation but above the plate floor.

70. The non-transitory computer readable storage medium of claim 69, wherein the first elevation is at an uppermost level of the plate.

71. The non-transitory computer readable storage medium of claims 69 or 70, wherein the second elevation is a non-printing elevation.

72. The non-transitory computer readable storage medium of one of claims 69 to 70, wherein the second plurality of plate structures comprise conditional printing structures.

73. The non-transitory computer readable storage medium of claim 72, wherein the conditional printing structures include one or more second-tier structures having a first elevation not intended to print unless adjacent first-tier printing structures at a higher elevation than the second-tier structures experience a loss of elevation.

74. The non-transitory computer readable storage medium of claim 73, wherein the one or more first-tier structures form a watermark and the one or more second-tier structures comprise a replacement watermark.

75. The non-transitory computer readable storage medium of one of claims 73 to 74, wherein the conditional printing structures define a plurality of elevations below the first elevation and above the plate floor.

76. The non-transitory computer readable storage medium of claim 75, wherein the plurality of elevations comprise a plurality of steps at different elevations.

77. The non-transitory computer readable storage medium of claim 75, wherein the plurality of elevations define a sloped line.

78. The non-transitory computer readable storage medium of one of claims 72 to 77, wherein the conditional printing structures comprise an indicator.

79. The non-transitory computer readable storage medium of claim 78, wherein the indicator comprises a wear indicator.

80. The non-transitory computer readable storage medium of claim 79, wherein the wear indicator comprises a plurality of features that form a code.

81. The non-transitory computer readable storage medium of one of claims 69 to 80, wherein the first plurality of plate structures comprise printing structures corresponding to relatively high ink coverage areas and the second plurality of plate structures comprise printing structures corresponding to relatively low ink coverage areas.