Patent Application
20190134994
A fluid-ejection device is a type of device that dispenses fluid in a controlled manner. For example, one type of fluid-ejection device is an inkjet-printing device, in which ink is ejected onto media to form an image on the print media. Furthermore, a roller-based fluid-ejection device includes printheads that eject fluid onto media as the media moves past a series of rollers. One type of printing system may print and dry images on a web of medium.
The drawings are provided to illustrate various examples of the subject matter described herein in this disclosure (hereinafter “herein” for short, unless explicitly stated otherwise) related to printing with moisture profiles and are not intended to limit the scope of the subject matter. The drawings are not necessarily to scale.
The same part numbers designate the same or similar parts throughout the figures.
Digital inkjet web printers, in some instances referred to as inkjet web presses, are commercially available for industrial and commercial printing. HP Inc., USA, for example, has available the HP Inkjet Web Press for high production commercial inkjet printing. In one example of the HP Inkjet Web Press, the first side of the web is printed and dried at a first printing station, the web is inverted, and then the second side is printed and dried at a second printing station positioned end-to-end with the first printing station.
Aqueous based inkjet printing may add a relatively large amount of moisture to the print medium substrate, but only in the printed area. In many instances, to fully (or at least sufficiently) dry the printed area, the unprinted area ends up being over-dried, thereby resulting in a moisture differential. In some examples, the unprinted area moisture may be up to and sometimes more than about 2 wt % less than the printed area. In many instances, it is desirable to have a uniform moisture level across the web in corrugation processes to assure bond strength between flutes and liner and to control board warp. In one example, desired uniformity from the corrugators is about ±0.5 wt %.
The non-uniform moisture application from inkjet printing may create some paper handling issues. In one example, when moisture is added to the paper, the moisture causes expansion due to fiber growth and relaxation of bonds. In one case where the addition of moisture is physically constrained, as in a heavy fill bounded by a picture frame of dry media that is not similarly expanding, waves (cockle) may form in the print medium, often down web. Wrinkles and creases in the web may be formed when the medium expansion transitions over rollers under tension.
In one example, drying is the largest power draw on the inkjet press, involving tens to low hundreds of kilowatts. With a uniform moisture content across the web, relatively more moisture may be retained in the web and thus less drying is needed. Pre-existing methods to achieve this goal often involve optimization of web handling and drying. In one example, spreading types of rollers are used. In the case of drying, some applications (such as Kodak Prosper) use drying between applications of some ink planes. This may result in significant dimensional changes due to growth, shrinkage, and the resulting hysteresis that make color to color alignment difficult.
In view of the aforementioned challenges related to shape change during drying, the Inventors have recognized and appreciated the advantages of printing using moisture profiles. Following below are more detailed descriptions of various examples related to printing apparatuses and methods, particularly those involving printing using moisture profiles. The various examples described herein may be implemented in any of numerous ways.
Provided in one aspect of the examples is a method, comprising: generating, using a processor, data of a negative of an image to be printed on a print medium; determining, using the processor, a moisture profile of a print job, which print job comprises the image and the negative, using data of the image and the data of the negative; generating, using the processor, printing instructions of the print job using at least the determined moisture profile; and printing the print job on the print medium using at least the printing instructions
Provided in another aspect of the examples is a method, comprising: generating, using a processor, printing instructions of a print job, which instructions involve a moisture profile of an image to be printed on a print medium and a negative of the image; disposing, using the printing instructions, a moisturizing agent over a first portion of the print medium to form the negative; and disposing, using the printing instructions, an ink composition over a second portion of the print medium to form the image
Provided in another aspect of the examples is a printing device, comprising: a printing component having at least one series of print bars arranged along an arc of the printing component, at least one of the remaining print bars is to dispense a moisturizing agent and at least one of the print bar is to dispense an ink composition; a dryer; and a plurality of web guides each having a long axis oriented parallel to the long axis of each of the other web guides, the web guides arranged to guide the web along a duplex printing path past the first series of print bars for printing on a first side of the web, then through the dryer for drying the first side of the web, then past the second series of print bars for printing on a second side of the web, and then through the dryer for drying the second side of the web.
To the extent applicable, the terms “first,” “second,” “third,” etc. herein are merely employed to show the respective objects described by these terms as separate entities and are not meant to connote a sense of chronological order, unless stated explicitly otherwise herein.
Provided in some examples herein includes a smaller footprint inkjet web press. Examples of the new web press described herein may offer relatively high quality, duplex web printing while minimizing, or even avoiding, the challenges of a vertical stack web press. While the term “printer” is used in several instances herein, the term is meant only as a non-limiting example of a device that is capable of printing—i.e., a “printing device.”
The term “footprint” here refers to the area covered by a part; “print bar” to an inkjet pen or other inkjet printhead unit for dispensing ink drops across a web; and “web” to a continuous sheet of printable medium.
First printing part 36 includes a first series of print bars 44a-44e arranged along an arc on a first side 46 of printing component 12. Second printing part 40 includes a second series of print bars 48a-48e arranged along an arc on a second side 50 of printing component 12. In one example arrangement, print bars 44a, 44b, 48a and 48b dispense a black ink composition, print bars 44c and 48c dispense a magenta ink composition, print bars 44d and 48d dispense a cyan ink composition, and print bars 44e and 48e dispense a yellow ink composition. Other dispensing configurations are also possible. For example, fewer or more than the number of the print bars as shown may be possible. In one example, instead of the ink composition configuration as shown in
The dryer described herein may take any suitable form. For example, the dryer may dry using air (e.g., forced air), radiant heat (e.g., infrared heating (“IR”)), or both. In one example, an IR emitter, alone or in combination with a reflector, may be located in a window an air bar, which has an air channel that may ejected air that is heated. At least one of such an air bar may be placed on one or both sides of the print medium so that the heated air (as a result of IR) may be used to dry the medium. In some instances, the IR heat is applied to the medium directly without additional forced air.
Dryer 18 includes a first dryer part 54 for drying web first side 38 and a second dryer part 56 for drying web second side 42. Dryer first part 54 includes a first group of perforated tubes 58 extending across the width of web 14 for directing heated air simultaneously on to both sides 38 and 42 uniformly across the width of web 14. Similarly, dryer second part 56 includes a second group of perforated tubes 60 extending across the width of web 14 for directing heated air simultaneously on to both sides 38 and 42 uniformly across the width of web 14. Some tubes 58 and 60 are not shown in
Although it may be adequate for some printing applications to distribute drying air across only one side 38 or 42, a two sided air drying configuration such as that shown in
Referring still to
Unlike a web press that uses a turn bar to invert the web for duplex printing, in one example of duplex printing path 28, the long axis of each web guide 66, 68 is oriented parallel to the long axis of each of the other web guides 66, 68. In this example, web 14 moves past first print bars 44a-44e along a rising arc in one direction, as indicated by arrows 72 in
Other turn bar and paper path configurations are also possible. In one example, a simplex printing system may be employed. In such a simplex printing system, several gears, meter rollers, trolleys, etc. may be strategically placed to provide the desired type of printing needed. The printing may involve, for example, preprint and/or litho laminated (“litholam”) (which may involve taking a print medium that has been printed and mounting it onto a corrugated substrate), etc. Examples of simplex printing systems include T400S and T1100S printers, available from HP Inc., USA.
In another example, a duplex printing system may be employed. For example, the printing system may include two printing engines. A larger or a smaller number of printing engines may also be possible. After one side of the print medium is printed, the print medium may be routed through a turn bar, which may flip the paper medium over, whereby the second side of the print medium is printed. Duplex printing is described further below. Examples of duplex printing systems include T400 printers, available from HP Inc., USA.
In one example, the duplex printing path 28 and arched printing station 32 described herein facilitate printing component 12 and dryer 18 to be accessed for service. Full access to print bars 44 and 48, web path 28, and dryer 18 may be gained simply by removing housing covers on the front and/or back sides of printing station 32. Also, in this example the tension in web 14 and its alignment to print bars 44, 48 is much easier to control along an arced web path 28 (at arrows 72, 74 in
The duplex printing path 28 and arched printing station 32 described herein may facilitate interstitial drying within the same compact footprint.
Air distribution tubes 58 and 60 may be arranged along both sides of web 14 in dryer parts 52 and 54. The air support of web 14 afforded by opposing tubes 58, 60 may be beneficial for interstitial drying to allow for longer spans of web 14 between web guides 66, 68. In other examples, it may be desirable to guide web 14 past more than one print bar 44a-44e, 48a-48e before drying. Indeed, a number of different configurations for web path 28 are possible without changing the structural configuration of print station 32 by threading web 14 into the desired path. For one example, web 14 could be threaded past both black (K) print bars 44a, 44b and 48a, 48b and down to dryer 18, and then past each of the other print bars 44c-44e and 48c-48e and down to dryer 18 in succession.
The printing devices described herein may be employed to implement various suitable printing methods, including those that involve using a moisture profile.
Referring to
A print medium may refer to any material suitable for an ink composition to be disposed upon, and the printed ink composition may be used to display a variety of forms and/or images, including text, graphics, characters, images, or photographs. The ink composition that may be employed herein is not limited and may be any aqueous and non-aqueous based ink compositions. A print medium may comprise vinyl media, cellulose-based paper media, various cloth materials, polymeric materials (examples of which include polyester white film or polyester transparent film), photopaper (examples of which include polyethylene or polypropylene extruded on one or both sides of paper), metals, ceramics, glass, or mixtures or composites thereof. In one example, the print medium is a paper, including at least one sheet of paper, a roll of paper, etc.
The processor may be, for example, a computer. It is noted that when any aspect of an example described herein is implemented at least in part as algorithms, the algorithms may be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers. The processor may be employed to perform any suitable functions.
As noted, for example in
As shown in
The method may also comprise printing the print job on the print medium using at least the printing instructions (S704). The printing process as shown in
The moisturizing agent disposed over a portion of the print medium to form the negative may comprise any suitable material. For example, the moisturizing agent may comprise water, including in one example consisting essentially of water, including in one example consisting of water. The water may be tap water, reverse osmosis (“RO”) water, deionized (“DI”) water, etc. The moisturizing agent may comprise a bonding agent and/or a fixer. The bonding agent may be any suitable agent. For example, the bonding agent may be an aqueous composition. In one example, the bonding agent may comprise a glycol and/or a salt. The glycol may be tetraethylene glycol. The salt may be a metal salt, such as a calcium salt. In one example, the bonding agent comprise less than about 15% glycol, and less than about 10% metal salt, balanced by water. Other compositions are also possible. The % herein may refer to wt % or vol %, depending on the context.
The moisturizing agent may comprise additional components. For example, the moisturizing agent may comprise a biocide, surfactant, humectant, or combinations thereof. Examples of a biocide may include any suitable antibacterial, antifungal, and/or antiviral compositions. Examples of a humectant ma include glycol and Dantocol® by Lonza, USA. Examples of a surfactant may include Tergital™ by Dow Chemical, USA. Other suitable materials may be used for any of the biocide, surfactant, and humectant as described herein. In one example, the moisturizing agent consists essentially of the water and the additional components described herein. In one example, the moisturizing agent consists of the water and the additional components described herein. In one example, the moisturizing agent consists essentially of the bonding agent and the additional components described herein. In one example, the moisturizing agent consists of the bonding agent and the additional components described herein.
The method as shown in
The methods as described herein may comprise other additional processes. For example, a drying process may be carried out. The drying may be applied to the portions of the print medium comprising the image and the negative, or it may be applied to the entire print medium.
The methods described herein may be implemented using a digital application of moisture from a negative of the printed content. In one example, an inkjet print bar may be employed, as described herein, alone or in combination with a bonding agent and/or a fixer, to jet a moisturizing agent onto a web. The agent may comprise primarily water and/or at least one of biocides, surfactants, and humectants; or comprise bonding agent if a bonding agent is employed. The “image” may be the negative of the printed image extracted from the image processing already happening in the data pipeline. Accordingly, the amount of moisture may be uniform, matching the fill level in the image, and not adding more moisture in that region.
The methods provided here may result in some surprising benefits. For example, the methods described herein may result in the printed content having a uniform moisture content, which is important for corrugation, shrinkage being more predictable, and the overall paper shape from an inkjet web press being better. Uniform moisture and predictable shrinkage in turn may result desirable packaging applications. Applying a more uniform level of moisture to the web during printing may reduce issues with paper shape (e.g., cockle, wrinkles, and creases). It may also result in much more uniform moisture profiles in the paper and predictable shrink post-drying because the unprinted areas are not over-dried. While the addition of the moisture for uniformity may be accomplished using analog methods, in at least one example it is desirable to use a negative of the printed image and digital application of moisture. One benefit of the moisture application may be reduction in overall drying power involved.
It should be appreciated that all combinations of the foregoing concepts (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein. It should also be appreciated that terminology explicitly employed herein that also may appear in any disclosure incorporated by reference should be accorded a meaning most consistent with the particular concepts disclosed herein.
The indefinite articles “a” and “an,” as used herein in this disclosure, including the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.” Any ranges cited herein are inclusive.
The terms “substantially” and “about” used throughout this disclosure, including the claims, are used to describe and account for small fluctuations, such as due to variations in processing. For example, they may refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US16/40360 | 6/30/2016 | WO | 00 |
