Patent Description:
High speed printing systems have been developed for printing on a substrate, such as a web of shrinkable polymeric film. Such a material typically exhibits both elasticity and plasticity characteristics that depend upon one or more applied influences, such as force, heat, chemicals, electromagnetic radiation, etc. These characteristics must be carefully taken into account during the system design process because it may be necessary: <NUM>. ) to control material shrinkage during imaging so that the resulting imaged film may be subsequently used in a shrink-wrap process, and <NUM>. ) to avoid system control problems by minimizing dynamic interactions between system components due to the elastic deformability of the substrate.

Also, a flexible web is subject to the formation of wrinkles therein, resulting in poor or even unacceptable print quality. A further issue is encountered in a print system using ink jet printheads to apply inks to a flexible web. A splice or wrinkle passing an ink jet printer during high speed production can damage one or more of the printheads of the printer, resulting in expensive downtime and the need to replace the damaged printheads, entailing significant replacement costs.

The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the invention, which is defined in the appended claims.

<CIT> discloses a dryer management system for drying web substrates. A web transport a printed substrate past dryer units through which heated air is expelled toward the substrate. A temperature sensor measures the temperature of the heated air within a dryer unit. <CIT> discloses an apparatus for drying of a medium. A transport unit conveys a medium past a drying device, a temperature sensor detects the temperature of the medium in the area of the medium that is heated by the drying device, and a control unit controls the drying device using the detected temperature as control parameter. <CIT> discloses a dryer that includes a transport conveyor to convey a film having a liquid applied through a dryer. The film includes a first surface on which a liquid has been applied and a second surface opposite the first surface. The dryer includes non-contact heaters that direct heated air toward the first surface and a heated drum that contacts and heats the second surface. Temperature sensors detect the temperature of the heated air and the heated drum, and a controller adjusts operation of the non-contact heaters and the drum using the detected temperatures as control parameters.

According to one aspect, a dryer management system to manage drying a material deposited on a web includes a web transport adapted to convey the web, a dryer unit or series of dryer units associated with and disposed downstream of an imager unit having at least heater unit adapted to generate a flow of heated air to heat the web, a temperature sensing device is disposed proximate the web to develop an indication of a temperature of the web as the web is conveyed past the heater unit; and a closed-loop dryer controller. The closed-loop dryer controller is configured to monitor the indication of the temperature and sufficiency of drying of material deposited on the web, and is configured to adjust operation of the heater unit to heat the web sufficiently to dry the material on the web and maintain the indication of the temperature of the web below a maximum temperature. Preferred embodiments of the dryer management system are set out in dependent claims <NUM> to <NUM>.

According to another aspect, a method of managing drying of a material deposited on a web includes the steps of conveying the web having an undried material deposited thereon, generating a flow of heated air to heat the web, developing an indication of a temperature of the web, and monitoring the indication of the temperature and sufficiency of drying of material deposited on the web. In addition, the method includes the further step of, in response to monitoring the indication of the temperature, adjusting at least one of a temperature of the heated air and a speed of the heated air to heat the web sufficiently to dry the material on the web and maintain the first temperature of the web below a maximum temperature. Preferred embodiments of the method are set out in dependent claims <NUM> to <NUM>.

Other aspects and advantages will become apparent upon consideration of the following detailed description and the attached drawings wherein like numerals designate like structures throughout the specification.

This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.

So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting the scope of the invention, which is defined in the appended claims. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:.

<FIG> shows an exemplary system <NUM> for printing content (e.g., images and/or text) on a substrate, such as a shrinkable plastic film used in food grade applications. It should be understood, however, that the system <NUM> may be used to print on any polymer or other flexible material that is dimensionally stable or unstable during processing for any application, e.g., other than food grade. The system <NUM> preferably operates at high-speed, e.g., on the order of zero to about <NUM> or more m/s (<NUM> or more feet per minute (fpm)) and even up to about <NUM>/s (<NUM> fpm), although the system may be operable at a different speed, as necessary or desirable. The illustrated system <NUM> is capable of printing images and/or text on both sides of a substrate (i.e., the system <NUM> is capable of duplex printing) although this need not be the case. In the illustrated embodiment, a first side of a substrate is imaged by a sequence of particular units during a first pass, the substrate is then turned over and the other side of the substrate is imaged by all of the particular units or only by a subset of the particular units during a second pass. First portions of one or more of the particular units may be operable during the first pass and second portions of one or more of the particular units laterally offset from the first portions may be operable during the second pass. Also, one or more of the particular units may be capable of simultaneously treating and/or imaging both sides of the substrate during one pass, in which case such unit(s) need not be operable during the other pass of the substrate. In the illustrated embodiment, the first portions are equal in lateral extent to the second portions, although this is not necessarily the case. Thus, for example, the system may have a <NUM> (<NUM> inch) width, and may be capable of duplex printing up to a <NUM> (<NUM> inch) wide substrate. Alternatively, a <NUM> (<NUM> inch) wide (or smaller) substrate may be printed on a single side (i.e., simplex printed) during a single production run. If desired, additional imager units and associated dryer and web guide units may be added in line with the disclosed imager units and other units so as to obtain full-width (i.e., <NUM> (<NUM> inch) in the disclosed embodiment) duplex printing capability. Still further, a substrate having a different width, such as <NUM> (<NUM> inches) (or larger or smaller width) may be accommodated.

Further, the illustrated system <NUM> may comprise a fully digital system that solely utilizes ink jet printers, although other printing methodologies may be utilized to image one or more layers, such as flexographic printing, lithographic offset printing, silk screen printing, intaglio printing, letterpress printing, etc. Ink jet technology offers drop on demand capability, and thus, among other advantages, allows high levels of color control and image customization.

In addition to the foregoing, certain ink jet heads are suitable to apply the high opacity base ink(s) that may be necessary so that other inks printed thereon can receive enough reflected white light (for example) so that the overprinted inks can adequately perform their filtering function. Some printhead technologies are more suitable for flood coating printing, like printing overcoat varnish, primers, and white, and metallic inks.

On the other hand, printing high fidelity images with high resolution printheads achieves the best quality. Using drum technology and printing with ink jet is the preferred way to maintain registration, control a flexible/shrinkable film substrate, and reproduce an extended gamut color pallet.

The system disclosed herein has the capability to print an extended gamut image. In some cases the color reproduction required may need a custom spot color to match the color exactly. In these cases, an extra eighth channel (and additional channels, if required) can be used to print custom color(s) in synchronization with the other processes in the system.

Printing on flexible/shrinkable films with water-based inks has many challenges and require fluid management, temperature control, and closed loop processes. Thus, in the present system, for example, the ability to maintain a high quality color gamut at high speed is further process controlled by sensor(s) that may comprise one or more calibration cameras to fine tune the system continually over the length of large runs.

As used herein, the phrase "heat-shrinkable" is used with reference to films which exhibit a total free shrink (i.e., the sum of the free shrink in both the machine and transverse directions) of at least <NUM>% at <NUM> (<NUM>°F), as measured by ASTM D2732. All films exhibiting a total free shrink of less than <NUM>% at <NUM> (<NUM>°F) are herein designated as being non-heat-shrinkable. The heat-shrinkable film can have a total free shrink at <NUM> (<NUM>°F) of at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, or at least <NUM>%, as measured by ASTM D2732. Heat shrinkability can be achieved by carrying out orientation in the solid state (i.e., at a temperature below the glass transition temperature of the polymer). The total orientation factor employed (i.e., stretching in the transverse direction and drawing in the machine direction) can be any desired factor, such as at least 2X, at least 3X, at least 4X, at least 5X, at least 6X, at least 7X, at least 8X, at least 9X, at least 10X, at least 16X, or from <NUM>. 5X to 20X, from 2X to 16X, from 3X to 12X, or from 4X to 9X.

As shown in <FIG>, the illustrated system <NUM> includes a first pull module <NUM> that unwinds a web of plastic web <NUM> from a roll <NUM> that is engaged by a nip roller <NUM> at the beginning of a first printing pass through the system <NUM>. The web <NUM> may comprise a flattened cylinder or tube of plastic film comprising two layers having sides 24a, 24b (see <FIG>) joined at side folds 24c, 24d, although the web <NUM> may instead simply comprise a single layer of material, if desired and as referred to above. Once unwound by the module <NUM>, the web <NUM> may be processed by a surface energy modification system, such as a corona treatment unit <NUM> of conventional type, that increases the surface energy of the web <NUM>. The corona treatment addresses an imaging condition that may be encountered when a large number of closely spaced drops are applied to a low surface energy impermeable material, which, if not compensated for, can result in positional distortion of the applied inks due to coalescence effects. The corona treatment module may be capable of treating both sides of the web <NUM> simultaneously. A first web guide <NUM> of conventional type that controls the lateral position of the web <NUM> in a closed-loop manner then guides the corona-treated web <NUM> a first imager unit <NUM>. A first dryer unit <NUM> is operated to dry the material that is applied to the web <NUM> by the first imager unit <NUM>. The material applied by the first imager unit <NUM> may be deposited over the entirety of the web <NUM> or may be selectively applied only to some or all areas that will later receive ink.

A second pull module <NUM> and a second web guide <NUM> (wherein the latter may be identical to the first web guide <NUM>) deliver the web <NUM> to a second imager unit <NUM> that prints a material supplied by a first supply unit <NUM> on the web <NUM>. A second dryer unit <NUM> is operable to dry the material applied by the second imager unit <NUM>.

Thereafter, the web <NUM> is guided by a third web guide <NUM> (again, which may be identical to the first web guide <NUM>) to a third imager unit <NUM> that applies material supplied by a second supply unit <NUM> thereon, such as at a location at least partially covering the material that was deposited by the second imager unit <NUM>. A third dryer unit <NUM> is operable to dry the material applied by the third imager unit <NUM> and the web <NUM> is then guided by a fourth web guide <NUM> (that also may be identical to the first web guide <NUM>) to a fourth imager unit <NUM> comprising a relatively high resolution, extended color gamut imager unit <NUM>.

The imager unit <NUM> includes a drum <NUM> around which are arranged ink jet printheads for applying primary process color inks CMYK to the web <NUM> along with secondary process color inks orange, violet, and green OVG and an optional spot color ink S to the web <NUM> at a relatively high resolution, such as <NUM> dots/mm (<NUM> dpi) and at a high speed (e.g., <NUM> - <NUM>/s (<NUM>-<NUM> fpm)). The extended gamut printing is calibrated at the high printing speed. The drop sizes thus applied are relatively small (on the order of <NUM>-<NUM> pL). If desired, the imager unit <NUM> may operate at a different resolution and/or apply different drop sizes. The inks are supplied by third and fourth supply units <NUM>, <NUM>, respectively, and, in some embodiments, the inks are of the water-based type. The process colors comprising the CMYK and OVG inks enable reproduction of extended gamut detailed images and high quality graphics on the web <NUM>. A fourth dryer unit <NUM> is disposed downstream of the fourth imager unit <NUM> and dries the inks applied thereby.

Following imaging, the web <NUM> may be guided by a web guide <NUM> (preferably identical to the first web guide <NUM>) and coated by a fifth imager unit <NUM> comprising an ink jet printer operating at a relatively low resolution and large drop size (e.g., <NUM> dots/mm (<NUM> dpi), <NUM>-<NUM> pL size drops) to apply an overcoat, such as varnish, to the imaged portions of the web <NUM>. The overcoat is dried by a fifth dryer unit <NUM>. Thereafter, the web is guided by a web guide <NUM> (also preferably identical to the first web guide <NUM>), turned over by a web turn bar <NUM>, which may comprise a known air bar, and returned to the first pull module <NUM> to initiate a second pass through the system <NUM>, following which material deposition/imaging on the second side of the web <NUM> may be undertaken, for example, as described above. The fully imaged web <NUM> is then stored on a take-up roll <NUM> engaged by a nip roll <NUM> and thereafter may be further processed, for example, to create shrink-wrap bags.

While the web <NUM> is shown in <FIG> as being returned to first the pull module <NUM> at the initiation of the second pass, it may be noted that the web may be instead delivered to another point in the system <NUM>, such as the web guide <NUM>, the first imager unit <NUM>, the pull module <NUM>, the web guide <NUM>, or the imager unit <NUM> (e.g., when the web <NUM> is not to be precoated), bypassing front end units and/or modules, such as the module <NUM> and the corona treatment unit <NUM>.

Further, in the case that the web <NUM> is to be simplex printed (i.e., on only one side) the printed web <NUM> may be stored on the take-up roll <NUM> immediately following the first pass through the system <NUM>, thereby omitting the second pass entirely.

The web <NUM> may be multilayer and may have a thickness of <NUM> or less, or a thickness of from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM>,<NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM>,<NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM>,<NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM> (<NUM> to <NUM> mils), or from <NUM> to <NUM>,<NUM> (<NUM> to <NUM> mils). The web <NUM> may have a film percent transparency (also referred to herein as film clarity) measured in accordance with ASTM D <NUM>-<NUM> "Standard Test Method for Transparency of Plastic Sheeting", published April, <NUM>, of at least <NUM> percent, or at least <NUM> percent, or at least <NUM> percent, or at least <NUM> percent.

Preferably, the system <NUM> includes a first tension zone between the roll <NUM> (which is a driven roll) and the pull module <NUM>, a second tension zone between the pull module <NUM> and the imager unit <NUM>, a third tension unit between the imager unit <NUM> and the pull module <NUM>, a fourth tension zone between the pull module <NUM> and the imager unit <NUM>, a fifth tension zone between the imager unit <NUM> and the imager unit <NUM>, a sixth tension zone between the imager unit <NUM> and the drum <NUM>, a seventh tension zone between the drum <NUM> and the imager unit <NUM>, and an eighth tension zone between the imager unit <NUM> and the take-up roll <NUM> (which is a driven roll). One or more tension zones may be disposed between the imager unit <NUM> and the pull module <NUM> and/or at other points in the system <NUM>. Each of the elements defining the ends of the tension zones comprises, for example, a driven roll (which, in the case of the imager units <NUM>, <NUM><NUM>, <NUM>, and <NUM>, comprise imager drums) with a nip roller as described in greater detail hereinafter. Preferably, all of the tension zones are limited to about <NUM> feet or less in length. The web tension in each tension zone is controlled by one or more tension controllers such that the web tension does not fall outside of predetermined range(s).

The nature and design of the first, second, and third imager units <NUM>, may vary with the printing methodologies that are to be used in the system <NUM>. For example, in a particular embodiment in which a combination of flexographic and ink jet reproduction is used, then the first imager unit <NUM> may apply a composition comprising a clear primer and a dispersion of a white colorant, such as titanium dioxide, in a flood-coated fashion to the web <NUM>. The second imager unit <NUM>, which may comprise an ink jet printer or a flexographic unit, may thereafter deposit one or more metallic ink(s) onto the web at least in portions that received material from the first imager unit <NUM>. In such an embodiment, the third imager unit <NUM> is not required, and the imager unit <NUM> and dryer unit <NUM> and web guide <NUM> associated therewith may be omitted.

In a further embodiment, the first imager unit <NUM> comprises a flexographic unit that applies a white pigmented ink to the web <NUM>, the second imager unit <NUM> comprises an ink jet printer or a flexographic unit that applies one or more metallic inks, and the third imager unit <NUM> comprises an ink jet printer or flexographic unit that applies a clear primer to the web <NUM>.

In yet another embodiment that uses ink jet technology throughout the system <NUM>, the first imager unit <NUM> comprising an ink jet printer may apply a composition comprising a clear primer and a dispersion of a white colorant, such as titanium dioxide, to the web <NUM>. The second imager unit <NUM>, which comprises an ink jet printer, may thereafter deposit one or more metallic ink(s) onto the web at least in portions that received material from the first imager unit <NUM>. In such an embodiment, the third imager unit <NUM> is not required, and the imager unit <NUM> and dryer unit <NUM> and web guide <NUM> associated therewith may be omitted.

In a still further embodiment, the first imager unit <NUM> comprises an ink jet printer that applies a white pigmented ink to the web <NUM>, the second imager unit <NUM> comprises an ink jet printer that applies one or more metallic inks, and the third imager unit <NUM> comprises an ink jet printer that applies a clear primer to the web <NUM>.

Any one or more of the imager units <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> may be omitted or the functionality thereof may be combined with one or more other imager units. Thus, for example, in the case where a combined primer and white pigmented material are applied, the combination may be printed by one of the imager units <NUM> or <NUM> and the other of the imager units <NUM>, <NUM> may be omitted.

In some embodiments each of the first, second, and third imager units <NUM>, <NUM>, <NUM> comprises a <NUM> dots/mm (<NUM> dpi (dots per inch)) inkjet printer that applies relatively large drops (i.e., at least <NUM>-<NUM> picoliters (pL)) each using piezoelectric ink jet heads, although the imager units <NUM>, <NUM>, and/or <NUM> may operate at a different resolution and/or apply different sizes of drops. Thus, for example, a printhead designed for use with metallic and precoating inks in the present system may have a resolution of <NUM> dots/mm (<NUM> dpi) and drop volume of <NUM>-<NUM> pL. The pre-coating material, white, and metallic inks have relatively heavy pigment loading and/or large particle sizes that are best applied by the relatively low resolution/large drop size heads of the imager units <NUM>, <NUM>, <NUM>.

In alternative embodiments, one or more of the primer, white, and coating imager units may operate at a relatively high resolution and/or small drop size, such as <NUM> dots/mm (<NUM> dpi) / <NUM>-<NUM> pL.

The primer renders at least a portion of the surface of the web <NUM> suitable to receive later-applied water-based inks. It is preferable (although not necessary) to apply the primer just before the process and spot color inks are applied by the fourth imager unit <NUM> so that the such colors are directly applied to the dried primer.

Preferably, the fourth imager unit <NUM> comprises the above-described ink jet printer so that drop-on-demand technology may be taken advantage of, particularly with respect to print-to-print variability, high resolution, and the ability to control registration precisely.

The fifth imager unit <NUM> also preferably comprises an ink jet printer that operates at least at <NUM> dots/mm or <NUM> dots/mm (<NUM> dpi or <NUM> dpi), although it may instead be implemented by a different printing methodology, such as a flexographic unit.

As noted in greater detail hereinafter, a supervisory or global control system <NUM> is responsive to sensors (not shown in <FIG>) and is responsible for overall closed-loop control of various system devices during a production run. A further control system comprising a print management control system <NUM> controls the various imager units also in a closed-loop fashion to control image reproduction as well as color correction, registration, correct for missing pixels, etc..

Also in the illustrated embodiment, each dryer unit <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> is controlled by an associated closed-loop dryer management system (not shown in <FIG>) during printing to, among other things, minimize image offsetting (sometimes referred to as "pick-off"), which can result in artifacts that may result from improper or insufficient drying of ink deposited on the web causing undried ink/coating to adhere (i.e., offset) to one or more system handling components, such as idler roller(s) or other component(s), and be transferred from such system handling component(s) to other portions of the web. It is understood that each dryer unit can be a like kind of dryer unit or distinct types of dryer units.

In the case of a partially or completely ink jet implemented system, the printheads used by the first through fifth imager units <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> may be of the same or different types, even within each printer, and/or, as noted previously, different printing methodologies could be used to apply inks/coatings. In any event, the global control system <NUM> and/or the print management control system <NUM> is (are) programmed to convert input data representing the various layers, such as data in a print-ready source format (e.g., Adobe Portable Document Format or PDF) to bitmaps by a ripping process or other page representation(s) during pre-processing taking into account the operational characteristics of the various printhead types/printing methodologies (such as the resolution(s) and drop size(s) to be deposited) and properties of the web (such as shrinkage when exposed to heat).

The pull module <NUM>, the web guides <NUM>, <NUM>, <NUM>, and <NUM>, and the rollers described above provide a web transport that conveys the web <NUM> past the imager units <NUM>, <NUM>, <NUM>, and <NUM>. Referring to <FIG>, each dryer unit <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> associated with an imager unit <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, respectively, comprises a closed-loop dryer controller <NUM>, an encoder roller <NUM>, one or more heater unit(s) 206a-206n, one or more temperature sensing devices 208a-208n, a roller <NUM>, and a camera <NUM>.

After the web <NUM> is printed on by the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, as described above, the web <NUM> is conveyed past the encoder roller <NUM> that generates a plurality of signals, one such signal for each revolution undertaken thereby. The imager unit <NUM> includes a plurality of printheads 228a-<NUM> that, for example, deposit process and/or spot color inks onto the web <NUM>.

Each heater unit 206a-206n is associated with a temperature sensing device 208a-208n, respectively, and the heater unit(s) 206a-206n and the temperature sensing device 208a-208n are disposed such that the web <NUM> is conveyed therebetween. Further, each heater unit <NUM> generates a flow of heated air that is blown toward a side <NUM> of the web <NUM> having material deposited thereon by the imager unit <NUM>, <NUM>, <NUM>, or <NUM>. In a preferred embodiment, the direction of the flow of heated air is perpendicular to the side <NUM> of the web <NUM>. However, the flow of heated air may be directed toward the web at other angles or even transverse to the web to heat the web.

The closed-loop dryer controller <NUM> monitors the drying of the material on the web <NUM> and an indication of a temperature of the web <NUM> developed by the temperature sensing device <NUM> to ensure that the material is sufficiently dried and that the temperature of the web <NUM> does not become so great as to damage the web (e.g., cause the web to shrink. ) All of closed-loop dryer controllers <NUM> of the system <NUM> are configured prior to a production run by a global dryer control system <NUM> in accordance with parameters of the production run. The global dryer control system <NUM> and the closed-loop dryer controller <NUM> comprise the closed-loop dryer management system <NUM> noted above.

After the web <NUM> passes between the heater unit(s) 206a-206n and the temperature sensing device(s) <NUM>, the web is conveyed past the roller <NUM> and the camera <NUM>. The roller <NUM> is the first roller (or any other component of the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) that contacts the side <NUM> of the web <NUM>, and thus any material deposited on such side <NUM>. The roller <NUM> may be an idler roller that supports the web <NUM>, a chiller roller that facilitates cooling of the web, or any other type of roller or component that first contacts the side <NUM> after the web <NUM> has been conveyed past the heater unit(s) 206a-206n. The camera <NUM> is positioned to capture one or more image(s) of the side <NUM> as the web <NUM> is conveyed thereby.

At the beginning of a production run (or print job), the global dryer control system <NUM> receives information regarding the production run from a data system <NUM> and configures the closed-loop dryer controller <NUM> with a minimum temperature the web <NUM> must reach to dry material deposited thereon by the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> associated with the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, respectively, and a maximum temperature that a temperature of the web cannot exceed to ensure the web does not undergo undesired shrinking or other damage. The global dryer control system <NUM> also determines a maximum speed at which the web <NUM> is conveyed to ensure that the web <NUM> has sufficient heater dwell time (i.e., exposure to the flow(s) of heated air generated by heater unit(s) 206a-206n) to dry the deposited material and configures a transport control <NUM> to set the conveyance speed of the web <NUM>.

<FIG> illustrates a computer system <NUM> especially adapted to implement the closed-loop dryer management system <NUM>, it being understood that any or all of the control systems disclosed herein, such as one or more of the control systems <NUM>, <NUM>, <NUM>, and/or <NUM>, may be implemented by like computer systems or by the computer system <NUM>. Thus, for example, the computer system <NUM> may also comprise one or more processing unit(s) <NUM> and may implement the closed-loop dryer management system <NUM>. Each processing unit <NUM> comprises a personal computer, server, or other programmable device having a memory <NUM> that, among other things, stores programming executed by one or more processing module(s) or controller(s) <NUM> to implement the closed-loop dryer management system <NUM>. One or more of the processing unit(s) <NUM> receive(s) signals from the temperature sensing device(s) <NUM> and other sensors, receive(s) signals from the web position encoder <NUM>, controls operation of heater units <NUM> and/or a blower <NUM> of the dryer units <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> and the camera <NUM>, and communicates with the supervisory control <NUM>, the data system <NUM>, and transport control <NUM>.

<FIG> is a flowchart <NUM>, of the steps undertaken by the global dryer control system <NUM> to configure the closed-loop dryer controller <NUM> and the transport control <NUM>. Specifically, at step <NUM>, the global dryer control system <NUM> receives, from the data system <NUM>, information regarding the production run including, for example, characteristics of the substrate that comprises the web <NUM>, a desired web conveyance speed, characteristics of the material deposited by each imager unit <NUM>, <NUM>, <NUM>, and <NUM>, resolution and drop sizes each imager unit <NUM>, <NUM>, <NUM>, and <NUM> is to deposit, and the content to be printed.

At step <NUM>, the global dryer control system <NUM> analyzes the content to be printed, the resolution to be printed by each imager unit <NUM>, <NUM>, <NUM>, and <NUM>, and the drop sizes that such imager units are configured to deposit to develop an estimate of a maximum material volume on any portion of the web <NUM> that is to be deposited by any of the imager units <NUM>, <NUM>, <NUM>, and <NUM>. Such maximum material volume may be represented as a dot-percent of material, a volume of material per area of the web, or another metric apparent to one who has ordinary skill in the art.

In some embodiments, the maximum material volume per area of the web <NUM> is calculated by another system (not shown) when the content is prepared for printing and stored in the data system <NUM>. In such embodiments, the global dryer control system <NUM> receives the maximum material volume per area from the data system, at step <NUM>.

At step <NUM>, the global dryer control system <NUM> determines, based on the characteristics of the substrate that comprises the web <NUM>, a maximum temperature such substrate may reach without being damaged. In some embodiments, the data system <NUM> includes such maximum temperature information for each type of substrate and the global dryer control system <NUM> retrieves such information.

In a preferred embodiment, the maximum web temperature determined at step <NUM> is less than a temperature that would cause shrinkage or other harm to the web <NUM>. For example, if a particular substrate that comprises the web <NUM> begins to shrink at a temperature of <NUM>°F (about <NUM>), the maximum web temperature may be set to <NUM>°F (about <NUM>).

Referring once again to <FIG>, at step <NUM>, the global dryer control system <NUM> determines the minimum web temperature the web <NUM> will have to reach in order to sufficiently dry the maximum material volume per area determined at step <NUM>. In some embodiments, the data system <NUM> includes information, for each type of material, the temperature a particular volume of such material must reach to be dried. In such embodiments, the global dryer control system <NUM> uses such material information and maximum material volume per area to determine the minimum web temperature the web will have to reach.

In a preferred embodiment, the minimum web temperature determined at step <NUM> is greater than the temperature at which the maximum volume of material per area that is to be deposited during the production run would dry completely. For example, if the maximum volume of material per area to be deposited for the production run would dry completely at a temperature of <NUM> (<NUM>°F), the minimum web temperature may be set to <NUM> (<NUM>°F).

In other embodiments, the global dryer control system <NUM> may calculate the minimum web temperature in accordance with the maximum web temperature determined at step <NUM> by, for example, multiplying the maximum web by a predetermined value greater than zero and less than <NUM>. In some embodiments, such predetermined value between is about <NUM> to about <NUM>. In other embodiments, such predetermined value is between about <NUM> and about <NUM>, and still other embodiments, such predetermined value is between about <NUM> and about <NUM>.

In some embodiments, the global dryer control system <NUM> calculates one minimum web temperature in accordance with the maximum volume of material per area that is deposited by all of the imager units <NUM>, <NUM>, <NUM>,<NUM>, and <NUM>. In other embodiments, the global dryer control system <NUM> calculates a minimum web temperature for each dryer unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> in accordance with a maximum volume of material per area that is expected to be deposited by the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, respectively, associated with such heater unit <NUM>.

At step <NUM>, the global dryer control system <NUM> calculates a necessary web speed that will provide sufficient heater dwell time for the web to reach the minimum web temperature estimated at step <NUM>. In some embodiments, the data system <NUM> provides information regarding the dwell time and temperature necessary for the material on the web <NUM> to sufficiently dry and the data system <NUM> or global dryer control system <NUM> determines the necessary web speed to provide such dwell time based on the material comprising the web <NUM> and the heating characteristics of the heater units <NUM>.

At step <NUM>, the global dryer control system <NUM> determines if the web speed calculated at step <NUM> is less than or equal to the desired web conveyance speed loaded at step <NUM>. If so, the global dryer control system <NUM> configures the transport control <NUM> to set the web speed for the production run to the desired web conveyance speed, at step <NUM>. Otherwise, at step <NUM>, the global dryer control system <NUM> configures the transport control <NUM> to set the web speed for the production run to the necessary web speed calculated at step <NUM>.

At step <NUM>, the global dryer control system <NUM> configures the closed-loop dryer controller <NUM> of each dryer unit <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> in accordance the minimum and maximum web temperatures determined at steps <NUM> and <NUM>, respectively.

At step <NUM>, the global dryer control system <NUM> determines a location along the width of the web <NUM> that is to receive the maximum material volume per area calculated in step <NUM>. In some embodiments, the global dryer control system <NUM> operates a camera <NUM> positioning apparatus (not shown) to automatically position the camera <NUM> so that the camera <NUM> is able to capture such determined location. In other embodiments, the global dryer control system <NUM> informs an operator to manually position the camera <NUM> so the camera <NUM> can capture the determined location. Thereafter, the global dryer control system <NUM> exits.

Referring once again to <FIG>, after the closed-loop dryer controller <NUM> and the transport control <NUM> have been configured by the global dryer control system <NUM>, and the production run started, each closed-loop dryer controller <NUM> operates the heating unit(s) <NUM> associated therewith to maintain the temperature of the web <NUM> between the minimum and maximum temperatures. In addition, the closed-loop dryer controller <NUM> detects if the material deposited on the web <NUM> is not being dried sufficiently and, for example, pick off is occurring and, in response, adjusts the heating unit(s) <NUM> associated therewith and/or the transport control <NUM> accordingly.

<FIG> shows a flowchart <NUM> of the steps undertaken by the closed-loop dryer controller <NUM> to maintain the temperature of the web <NUM> and to detect and prevent insufficient drying. Referring to <FIG>, at step <NUM>, the closed-loop dryer controller <NUM> loads the minimum and maximum temperature information determined by the global dryer control system <NUM> at steps <NUM> and <NUM> (<FIG>).

At step <NUM>, the closed-loop dryer controller <NUM> selects which ones of the heating unit(s) 206a-206n available in the drying unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> will be operated to maintain the temperature of the web <NUM> at least at the minimum temperature during the production run. In some embodiments, the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be configured with only one heater unit <NUM>. In other embodiments, the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, <NUM> may be configured with as many as <NUM> (or more) heater units <NUM> and only a subset of such heater units may be used during the production run. In situations, where heavy material coverage is expected or a slow drying material is deposited on the web <NUM>, all of the available heater units <NUM> may be used. In some embodiments, all of the heater units <NUM> may be used when the production run is started and the number of heater units <NUM> may be adjusted during the production run in response to monitoring of the temperature of the web <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> determines a temperature and a speed of the flow of heated air generated by each selected heater unit <NUM> during the production run. For example, a first one of the selected heater units (e.g., heater unit 206a) that the web <NUM> passes after having been printed on may be configured to direct the flow of heated air toward the face <NUM> of the web <NUM> at a lower speed and higher temperature than a subsequent heater unit <NUM>. It should be apparent to one of ordinary skill the art that the material deposited on the web <NUM> is relatively fluid when the web <NUM> reaches the first heater unit 206a and that directing the flow of heated air at a high speed may disturb such material. As the material dries, the flow of heated air may be directed at the web at higher speeds without disturbing the material.

In some embodiments, the closed-loop dryer controller <NUM> sets the speed of the heated air generated by the first heater unit 206a to be between about <NUM><NUM>/s and <NUM><NUM>/s per linear cm of the web <NUM> (<NUM> and about <NUM> cubic feet per minute per linear inch of the width of the web <NUM>). Such air flow speed may be incrementally increased at one or more subsequent heater units 206b through 206n until the speed of the heated air generated by the heater unit <NUM> that is operated and is most distal from the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> is approximately <NUM><NUM>/s per linear cm of the web <NUM> (approximately <NUM> cubic feet per minute per linear inch of a width the web <NUM>).

Further, it should be apparent to one who has ordinary skill in the art, that evaporation of solvent in the material as the web <NUM> passes past the heater units <NUM> facilitates cooling of the web <NUM>. Thus, the flow of heated air generated by the first heater unit 206a toward the web <NUM> may have a higher temperature because the solvent content of the material exposed to such flow of heated air is highest relative to when the material is exposed to air from subsequent heater unit(s) 206b-206n.

In some embodiments, the flow of heated air generated by the first heater unit 206a exceeds the temperature at which the web <NUM> begins to shrink (i.e., a shrink temperature). For example, if the shrink temperature of the web is <NUM>°F (about <NUM>), the temperature of the flow of heated air generated by the first heater unit 206a may be set to about <NUM>°F (about <NUM>). Further, the temperature of the airflow generated by subsequent heater unit(s) 206b-206n may ramp downward so that the airflow generated by the heater unit <NUM> most distal from the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> is near the shrink temperature of the web (or less).

At step <NUM>, the closed-loop dryer controller <NUM> configures each heater unit <NUM> selected at step <NUM> to generate the flow of heated air in accordance with the speed and temperature determined at step <NUM> for that heater unit <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> waits to receive a job start signal, for example, from the supervisory control system <NUM> (<FIG>), that indicates that the production run is to begin. Also at step <NUM>, the closed-loop dryer controller <NUM> directs the heater unit(s) <NUM> selected at step <NUM> to begin generating the flow of heated air.

At step <NUM>, the closed-loop dryer controller <NUM> polls the temperature sensing devices <NUM> associated with the heater units <NUM> being used for the production run to acquire a temperature of the web <NUM> sensed by each temperature sensing device <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> determines whether insufficient drying of the material may be occurring, as described in greater detail below.

At step <NUM>, the closed-loop dryer controller <NUM> determines if the web temperature sensed by any of the temperature sensing devices polled at step <NUM> exceeds the maximum web temperature loaded at step <NUM> and, if so, proceeds to step <NUM>. Otherwise, the closed-loop dryer controller <NUM> proceeds to step <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> adjusts operation of the heater unit(s) <NUM> to facilitate reducing the temperature of the web <NUM> and then proceeds to step <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> checks if the temperature of the web <NUM> determined at step <NUM> is too low for the material deposited thereon to dry or if insufficient drying of the material was determined at step <NUM> and, if so, the closed-loop dryer controller <NUM> proceeds to step <NUM>. Otherwise, the closed-loop dryer controller <NUM> proceeds to step <NUM>. In particular, the closed-loop dryer controller <NUM> analyzes the temperatures of the web <NUM> sensed by all of the temperature sensing device <NUM> and if none of the sensed temperatures of the web <NUM> exceed the minimum web temperature, the closed-loop dryer controller <NUM> determines that web temperature is too low.

At step <NUM>, the closed-loop dryer controller <NUM> adjusts operation of the heater unit(s) <NUM> to facilitate raising the temperature of the web <NUM>, and then proceeds to step <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> determines if a job send signal has been received from the supervisory control system <NUM>. If such signal has not been received, the closed-loop dryer controller <NUM> returns to step <NUM>. Otherwise, the closed-loop dryer controller <NUM> initiates a shutdown process for the heater units <NUM> and exits.

<FIG> shows a flowchart <NUM> of steps undertaken at step <NUM> (<FIG>) by the closed-loop dryer controller <NUM> to determine if the material on the web <NUM> is insufficiently dried. Referring to <FIG> and <FIG>, as described above, insufficient drying of the web may be detected when the material deposited on the side <NUM> of the web <NUM> contacts a roller, e.g. roller <NUM>, before such material is fully dried. A portion of the undried material is transferred to the roller <NUM>, and then from the roller <NUM> to a subsequent portion of the side <NUM> of the web <NUM>.

Referring to <FIG>, at step <NUM>, the closed-loop dryer controller <NUM> determines if the camera <NUM> has acquired an image of the web <NUM> is available for analysis. If no such image has been acquired, the closed-loop dryer controller <NUM> proceeds to step <NUM>, otherwise the closed-loop dryer controller <NUM> proceeds to step <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> analyzes the content that is to be printed to determine a first time in the future when an image will be printed by the imager unit <NUM>, <NUM>, <NUM>, <NUM> on a first portion of the web <NUM> and that will in the field of view of the camera <NUM>. At step <NUM>, the closed-loop dryer controller <NUM> uses the frequency of the signals generated by the encoder roller <NUM> (<FIG>) and a predefined circumference of the encoder roller <NUM> to determine the speed of the web <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> determines in accordance with the first time and the web speed, a second time when a second portion of the web <NUM> immediately following the first portion of the web <NUM> and that is supposed to be free of material will be in the field of view of the camera <NUM>.

At step <NUM>, the closed-loop dryer controller <NUM> set a trigger to cause the camera <NUM> to acquire an image of the second portion of the web <NUM> at the second time and store such image in a memory location accessible by closed-loop dryer controller <NUM> and the camera <NUM>. In one embodiment, at step <NUM>, the closed-loop dryer controller <NUM> sets a timer that causes an interrupt to be generated at the second time. In addition, the closed-loop dryer controller <NUM> associates an image capture process to be initiated when such interrupt is generated. Such image capture process directs the camera <NUM> to acquire the image, receives the acquired image, and stores the acquired image in the shared memory. Other ways of triggering the camera <NUM> to capture an image at particular time apparent to one who has ordinary skill in the art may be used.

After the trigger has been set at step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> of <FIG>.

If, at step <NUM>, the closed-loop dryer controller <NUM> determines that an image is available for analysis (i.e., an image acquired in response to the trigger set at step <NUM> being actuated), the closed-loop dryer controller <NUM>, at step <NUM>, analyzes the acquired image. As described above, the captured image is of the second portion of the web <NUM> that is expected to be free of any material. The closed-loop dryer controller <NUM> analyzes the captured image to determine if any pixels thereof have a value that indicates that material has been transferred to the second portion of the web <NUM>. For example, the closed-loop dryer controller <NUM> may apply a threshold operation to the acquired image that selects pixels having intensity values greater than a predetermined intensity value. If at least a predetermined number of pixels are selected as a result of such threshold operation, then the closed-loop dryer controller <NUM> determines that material transfer from the roller <NUM> to the second portion has occurred. Otherwise, the closed-loop dryer controller <NUM> determines that no such material transfer has occurred. It should be apparent that other ways of analyzing the captured image to determine whether material transfer has occurred apparent to one who has ordinary skill in the art may be used. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> of <FIG>.

<FIG> is a flowchart <NUM> of the steps undertaken by the closed-loop dryer controller <NUM> to reduce the temperature of the web <NUM>. Referring to <FIG>, the closed-loop dryer controller <NUM>, determines, at step <NUM>, if the speed of the flow of heated air can be adjusted to reduce the temperature of the web <NUM>. If so, then at step <NUM>, the closed-loop dryer controller <NUM> directs the one or more of the heater units 206a-206n to reduce the speed of the flow of heated air of generated thereby, and thus reduce the convection of heat from the such heater units <NUM> to the web <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

If at step <NUM>, the closed-loop dryer controller <NUM> determines that the speed of the flow of heated air cannot be adjusted, then, at step <NUM>, the closed-loop dryer controller <NUM> determines if the temperature of the heated air generated by one or more heater unit(s) 206a-206n can be reduced. For example, if the all of the heater unit(s) 206a-206n are operating at their minimum operating temperature, then such temperature cannot be reduced.

If the temperature of the flow of heated air can be reduced, then at step <NUM>, the closed-loop dryer controller <NUM> selects a heater unit <NUM> and directs such heater unit <NUM> to generate the flow of heated air at a lower temperature. In one embodiment, the closed-loop dryer controller <NUM> selects the heater unit <NUM> operating at the highest temperature and reduces the temperature of such heater unit <NUM> by a predetermined amount (e.g., <NUM>°F) or by a percentage of the current setting of the temperature of the flow of heated air (e.g., <NUM>%). In other embodiments, the closed-loop dryer controller <NUM> selects and reduces the temperature of the flow of heated air generated by the heater unit <NUM> most distal to the imager unit <NUM>, <NUM>, <NUM>, or <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>). It should be that other ways to select the heater unit <NUM> to adjust in this manner and/or amount of such adjustment apparent to one who has ordinary skill in the art may be used.

If at step <NUM>, the closed-loop dryer controller <NUM> determines that the temperature of one of the heater unit(s) 206a-206n cannot be reduced, the closed-loop dryer controller <NUM> determines, at step <NUM>, if more than one heater unit 206a-206n is operating and, if so, whether one such heater unit <NUM> can be turned off. If so, then at step <NUM>, the closed-loop dryer controller <NUM> turns off the heater unit <NUM> most distal, most proximal, or intermediate the most distal and most proximal from the imager unit <NUM>, <NUM>, <NUM>, or <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>). In an exemplary embodiment the closed-loop dryer controller <NUM> turns off the heater unit <NUM> that is operating and is most distal from the image unit <NUM>, <NUM>, <NUM>, or <NUM>.

If at step <NUM>, the closed-loop dryer controller <NUM> determines that one of the heater unit(s) 206a-206n cannot be turned off, the closed-loop dryer controller <NUM>, at step <NUM> determines if the conveyance speed of the web <NUM> can be increased (e.g., if the web <NUM> is not being conveyed at maximum speed) to reduce the heater dwell time of the web <NUM>. If so, the closed-loop dryer controller <NUM> directs the transport control <NUM> to increase the web speed, at step <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

If at step <NUM>, the closed-loop dryer controller <NUM> determines that the web speed cannot be increased, then, in some embodiments, the closed-loop dryer controller <NUM>, at step <NUM>, generates an error signal to, for example, the supervisory control system <NUM> that the temperature of the web <NUM> cannot be reduced and an operator should be alerted and/or a shutdown procedure started. Thereafter, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

<FIG> is a flowchart <NUM> of the steps undertaken by the closed-loop dryer controller <NUM> to raise the temperature of the web <NUM>. Referring to <FIG>, the closed-loop dryer controller <NUM>, at step <NUM>, determines if the speed of the flow of heated air can be adjusted to raise the temperature of the web <NUM>. If so, then at step <NUM>, the closed-loop dryer controller <NUM> increases the speed of the flow of heated air of one or more of the heater unit(s) 206a-206n to increase the convection of heat from the such heater unit(s) <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

Otherwise, at step <NUM>, the closed-loop dryer controller <NUM> determines if the temperature of the flow of heated air generated by one or more heater units 206a-206n can be increased. For example, if the all of the heater unit(s) 206a-206n are operating at their maximum operating temperature, then such temperature cannot be increased.

If the temperature of the flow of heated air can be increased, then at step <NUM>, the closed-loop dryer controller <NUM> selects a heater unit <NUM> and directs such heater unit <NUM> to generate the flow of heated air at a higher temperature. In one embodiment, the closed-loop dryer controller <NUM> selects the heater unit <NUM> operating at the lowest temperature and increases the temperature of such heater unit <NUM> by a predetermined amount (e.g., <NUM>°F) or by a percentage of the current setting of the temperature of the flow of heated air (e.g., <NUM>%). In other embodiments, the closed-loop dryer controller <NUM> selects and increases the temperature of the flow of heated air generated by the heater unit <NUM> most proximal to the imager unit <NUM>, <NUM>, <NUM>, or <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>). Other ways to select a heater unit <NUM> to adjust in this manner and/or amount of such adjustment apparent to one who has ordinary skill in the art may be used.

If at step <NUM>, the closed-loop dryer controller <NUM> determines that the temperature of the flow of air generated by any of the heater unit(s) 206a-206n cannot be raised to increase the temperature of the web <NUM>, the closed-loop dryer controller <NUM> determines, at step <NUM> if all of the heater units 206a-206n are operating or if an additional heater unit <NUM> can be turned on. If an additional heater unit <NUM> can be turned on, then at step <NUM>, the closed-loop dryer controller <NUM> turns on an additional heater unit <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>). In some embodiments, the closed-loop dryer controller <NUM> turns on the heater unit <NUM> that is not operating and that is most distal, most proximate, or intermediate from the imager unit <NUM>, <NUM>, <NUM>, or <NUM>. In an exemplary embodiment, the closed-loop dryer controller <NUM> turns on the heater unit <NUM> that is not operating and that is most proximate the imager unit <NUM>, <NUM>, <NUM>, or <NUM>.

If at step <NUM>, if the closed-loop dryer controller <NUM> determines that all of the heater units 206a-206n are operating, the closed-loop dryer controller <NUM>, at step <NUM> determines if the conveyance speed of the web <NUM> can be decreased to increase the heater dwell time of the web <NUM>. If so, the closed-loop dryer controller <NUM> directs the transport control <NUM> to reduce the web speed, at step <NUM>. After undertaking step <NUM>, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

If, at step <NUM>, the closed-loop dryer controller <NUM> determines that the web speed cannot be reduced, then, in some embodiments, the closed-loop dryer controller <NUM>, at step <NUM>, generates an error signal to, for example, the supervisory control system <NUM> that the temperature of the web <NUM> cannot be increased and an operator should be alerted and/or a shutdown procedure started. Thereafter, the closed-loop dryer controller <NUM> proceeds to step <NUM> (<FIG>).

Referring once again to <FIG>, in some embodiments each heater unit <NUM> is coupled by a corresponding air duct to a turbo-blower unit <NUM>. The turbo-blower unit <NUM> supplies a flow of unheated air to all of the heater unit(s) 206a-206n, which in turn heat such flow of unheated air and to create the flow of heated air directed toward the web <NUM>. In some embodiments, the closed-loop dryer controller <NUM> adjusts the speed of the flow of unheated air generated by turbo-blower unit <NUM> to increase or decrease the speed of the flow of heated air generated by all of the heater unit(s) 206a-206n. In addition, the closed-loop dryer controller <NUM> may individually adjust a heater unit <NUM> to increase or decrease the speed of the flow of heated air generated thereby independently of the other heater units <NUM>.

In some embodiments, the temperature sensing device <NUM> may be a temperature sensor that directly senses the temperature of the web <NUM> to develop an indication of the temperature of the web <NUM>. However, in some cases it may not always be feasible to directly sense the temperature of the web <NUM>. For example, a contact temperature sensor may interfere with conveyance of the web <NUM>. However, a contactless temperature sensor, e.g., an infrared temperature sensor, may not accurately sense the temperature of the web <NUM> because, for example, the web <NUM> has portions that are clear or has material disposed thereon that is of varying colors and/or comprises one or more metallic component(s). <FIG> illustrate two embodiments of temperature sensing devices <NUM> that use a contact less temperature sensor <NUM> to develop an indication of the temperature of the web <NUM>.

Referring to <FIG>, the temperature sensing device <NUM> includes a heat-conductive roller <NUM>, such as an idler roller, disposed opposite the heater unit <NUM> and the web rides on such heat-conductive roller <NUM>. The heat-conductive roller <NUM> is heated by the web <NUM> and the temperature sensor <NUM> monitors the temperature of the heat-conductive roller <NUM> to develop an indication of the temperature of the web <NUM>.

Alternately, referring to <FIG>, instead of the roller <NUM>, the temperature sensing device <NUM> includes a heat-conductive plate <NUM> disposed opposite the heater unit <NUM> and the web <NUM> is conveyed past such plate <NUM>. The heat-conductive plate <NUM> is heated by the web <NUM> and the temperature sensor <NUM> monitors the temperature of the heat-conductive plate <NUM> to develop an indication of the temperature of the web <NUM>. It should be apparent that in such embodiments, the temperature sensor <NUM> may be a contact less sensor or may be a contact sensor attached to the plate <NUM>.

Other configurations and ways of operating the temperature sensing device <NUM> to develop an indication of the temperature of the web <NUM> apparent to those who have ordinary skill in the art may be used.

In some embodiments, additional sensors may be disposed in or proximate the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> to sense the ambient conditions proximate thereto. For example, a humidity sensor (not shown) may be disposed proximate the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> to sense the humidity proximate thereto and the global dryer control system <NUM> and/or the closed-loop dryer controller <NUM> may use information from such additional sensors to adjust the speed and/or temperature of the airflow generated by the heater unit(s) <NUM>.

Referring to <FIG>, the dryer unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> may include additional components including for example one or more roller(s) (e.g., roller <NUM>) or other components (not shown) to guide and/or support the web <NUM> as it is conveyed through such dryer unit.

In some embodiments, the global dryer control system <NUM> may receive information from the closed-loop dryer controller <NUM> regarding whether the initial necessary web speed and minimum temperature developed at the start of a particular production run did not result in material deposited on the web <NUM> being sufficiently dried. The global dryer control system <NUM> may adjust the information in the global data system <NUM> that a slower web speed and/or higher temperature should be used for other production runs that have characteristics similar to the particular production run.

In some embodiments, the global dryer control system <NUM> may monitor the content that is going to printed by the imager unit <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> during a production run. If the global dryer control system <NUM> determines that the characteristics of such content will result in a substantially more or less volume of the material being deposited on the web <NUM>, the global dryer control system <NUM> may develop an updated necessary web speed and/or minimum temperature the web <NUM> should reach and reconfigure the closed-loop dryer system in accordance with such updated web speed and temperature.

It should be apparent to those who have skill in the art that any combination of hardware and/or software may be used to implement the supervisory system <NUM>, the closed-loop dryer controller <NUM>, the global dryer control system <NUM>, the data system <NUM>, and the transport control <NUM>. described herein. It will be understood and appreciated that one or more of the processes, sub-processes, and process steps described in connection with <FIG> and <FIG> may be performed by hardware, software, or a combination of hardware and software on one or more electronic or digitally-controlled devices. The software may reside in a software memory (not shown) in a suitable electronic processing component or system such as, for example, one or more of the functional systems, controllers, devices, components, modules, or sub-modules schematically depicted in <FIG> and <FIG>. The software memory may include an ordered listing of executable instructions for implementing logical functions (that is, "logic" that may be implemented in digital form such as digital circuitry or source code, or in analog form such as analog source such as an analog electrical, sound, or video signal). The instructions may be executed within a processing module or controller (e.g., the supervisory system <NUM>, the closed-loop dryer controller <NUM>, the global dryer control system <NUM>, the data system <NUM>, and the transport control <NUM>), which includes, for example, one or more microprocessors, general purpose processors, combinations of processors, digital signal processors (DSPs), field programmable gate arrays (FPGAs), or application-specific integrated circuits (ASICs). Further, the schematic diagrams describe a logical division of functions having physical (hardware and/or software) implementations that are not limited by architecture or the physical layout of the functions. The example systems described in this application may be implemented in a variety of configurations and operate as hardware/software components in a single hardware/software unit, or in separate hardware/software units.

The executable instructions may be implemented as a computer program product having instructions stored therein which, when executed by a processing module of an electronic system, direct the electronic system to carry out the instructions. The computer program product may be selectively embodied in any non-transitory computer-readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as an electronic computer-based system, processor-containing system, or other system that may selectively fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, computer-readable storage medium is any non-transitory means that may store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer-readable storage medium may selectively be, for example, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. A non-exhaustive list of more specific examples of non-transitory computer readable media include: an electrical connection having one or more wires (electronic); a portable computer diskette (magnetic); a random access, i.e., volatile, memory (electronic); a read-only memory (electronic); an erasable programmable read only memory such as, for example, Flash memory (electronic); a compact disc memory such as, for example, CD-ROM, CD-R, CD-RW (optical); and digital versatile disc memory, i.e., DVD (optical).

It will also be understood that receiving and transmitting of signals or data as used in this document means that two or more systems, devices, components, modules, or sub-modules are capable of communicating with each other via signals that travel over some type of signal path. The signals may be communication, power, data, or energy signals, which may communicate information, power, or energy from a first system, device, component, module, or sub-module to a second system, device, component, module, or sub-module along a signal path between the first and second system, device, component, module, or sub-module. The signal paths may include physical, electrical, magnetic, electromagnetic, electrochemical, optical, wired, or wireless connections. The signal paths may also include additional systems, devices, components, modules, or sub-modules between the first and second system, device, component, module, or sub-module.

In summary, a dryer management system <NUM> is disclosed herein that operates on or more dryer unit(s) <NUM>, <NUM>, <NUM>, <NUM>, and/or <NUM> to dry material disposed on a web. It should be apparent to one who has ordinary skill in the art that the embodiments of the dryer management system <NUM> disclosed herein may be adapted to dry any type of material deposited on any type of substrate using heat and/or a flow of heated air. Further, it should be apparent such embodiments may be adapted to dry material deposited on a substrate using any type of material deposition process.

The use of the terms "a" and "an" and "the" and similar references in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

Claim 1:
A dryer management system to manage drying a material deposited on a web (<NUM>), comprising:
a web transport (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) adapted to convey the web;
a dryer unit (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) associated with and disposed downstream of an imager unit (<NUM>, <NUM>, <NUM>, <NUM>) having at least one heater unit (206a, 206b, ...206n) adapted to generate a flow of heated air to heat the web;
a temperature sensing device (208a, 208b, ...208n) disposed proximate the web to develop an indication of a temperature of the web as the web is convey past the heater unit (206a, 206b, ...206n); and characterized by comprising
a closed-loop dryer controller (<NUM>) configured to monitor the indication of the temperature developed by the temperature sensing device (208a, 208b, ...208n) and sufficiency of drying of material deposited on the web and configured to adjust operation of the heater unit (206a, 206b, ...206n) to heat the web sufficiently to dry the material deposited on the web and maintain the indication of the temperature developed by the temperature sensing device (208a, 208b, ...208n) below a maximum temperature.