Patent Application
20140318397
1. Field of Disclosed Subject Matter
This disclosure relates to systems and methods for optimizing a multi-color variable data digital offset lithographic system by controlling characteristics of one or more individual color inks or relative donor/receiver surface characteristics to maximize ink transfer of a particular color ink layer onto a receiver surface including the surface of an image receiving medium substrate, or onto other color ink layers deposited on the receiver surface when forming digital output images, including multi-color digital output images, with a proposed variable digital data offset lithographic image forming system architecture.
2. Related Art
Lithography is a common method of printing or marking images on an image receiving medium. Depending on a configuration of a conventional lithography system, a highly-viscous lithographic ink may be transferred directly to a substrate of image receiving medium, such as paper, or may be transferred to an intermediate transfer surface or member for further transfer to the image receiving medium substrate. This latter configuration is referred to as an offset lithographic printing system. An intermediate transfer member is often comprised of a surface that is covered with a conformable coating or sleeve that constitutes the intermediate transfer surface, and that can conform to the surface topography of the image receiving medium substrate. Using the intermediate transfer member with the conformable surface may provide an ability within the system to compensate for image receiving media substrates that may have surface peak-to-valley depths that are somewhat greater than the surface peak-to-valley depths than could reasonably be accommodated by an etched imaging plate. Sufficient pressure is used to transfer the image from the intermediate transfer member to the image receiving medium substrate. The image receiving medium substrate is pinched between the intermediate transfer member and an impression cylinder that provides pressure against the intermediate transfer member to provide a transfer nip. At the transfer nip, the inked image pattern deposited on the surface of the intermediate transfer member is transferred to the image receiving medium substrate.
Conventional lithographic and offset lithographic printing techniques use plates that are permanently patterned (etched), and are, therefore, generally considered to be useful only when printing a large number of copies of the same image in long print runs, such as for magazines, newspapers, and the like. These conventional processes are generally not considered amenable to creating and printing a new pattern from one page to the next because, according to previously known methods, removing and replacing of individual printing plates, including on a print cylinder, would be required in order to change images. For these reasons, conventional lithographic techniques cannot accommodate true high speed variable data printing in which the images change from impression to impression, for example, as in the case of digital printing systems.
The lithography process has the advantage, however, of providing very high quality printing at least in part due to the comparatively high pigment loading and color gamut of the lithographic inks. The lithographic inks typically have a high color pigment content in a range of 20-70% by weight. Based on this advantage and a comparatively low cost of the inks, a desire arose to find some manner by which to implement variable data lithographic image forming.
Among the disadvantages encountered in attempting to modify conventional lithographic systems for variable digital data printing, even as configurations of digital data printing devices have emerged, is with respect to a relatively low transfer efficiency of the inks from the imaging surfaces of particular imaging members to intermediate transfer surfaces and to image receiving media substrates. Common conventional lithographic printing processes operate with ink transfer efficiencies on the order of approximately 50%, i.e., about half of the ink that is applied to the imaging surface actually transfers to the image receiving medium substrate. In conventional lithographic image forming, in a situation where the images do not change across large print runs, this relatively low transfer efficiency is not generally considered to be a drawback. On the other hand, proposed variable digital data lithographic image forming schemes require higher transfer efficiencies in order to produce high quality variable digital data images (with no ghosting) while not requiring significant modifications in traditional imaging surface cleaning systems and methods. Previously proposed systems by which attempts have been made to modify conventional lithographic process to support variable digital data image forming have fallen short in a number of ways including in providing relatively high transfer efficiencies for individual images, greater than 90% for example, to reduce ink waste that must be stripped off between image re-formation and the associated costs.
In order to address the shortfalls in adapting conventional lithographic image forming techniques to variable digital data image forming, U.S. Patent Application Publication No. 2012/0103212 A1 (the 212 Publication) published May 3, 2012 and based on U.S. patent application Ser. No. 13/095,714, which is commonly assigned and the disclosure of which is incorporated by reference herein in its entirety, proposes systems and methods for providing variable digital data lithographic and offset lithographic printing or image receiving medium marking. The systems and methods disclosed in the 212 Publication are directed to improvements on various aspects of previously-attempted variable data imaging lithographic marking concepts based on variable patterning of a particularly-formulated dampening fluid, to achieve effective truly variable digital data lithographic printing.
According to the 212 Publication, a comparatively smooth reimageable surface is provided on an imaging member, which may be a drum, plate, cylinder, belt or the like. The reimageable surface may be formed of a relatively thin layer over a mounting layer, a thickness of the relatively thin layer being selected to balance printing or marking performance, durability and manufacturability.
The 212 Publication describes, in requisite detail, an exemplary variable digital data lithographic image forming system 100 such as that shown, for example, in
As shown in
The exemplary system 100 includes a dampening fluid subsystem 120 for uniformly wetting the reimageable surface of the imaging member 110 with a particularly-formulated dampening fluid. A purpose of the dampening fluid subsystem 120 is to deliver a layer of dampening fluid, generally having a uniform and controlled thickness, to the reimageable surface of the imaging member 110. The dampening fluid may comprise water optionally with small amounts of isopropyl alcohol or ethanol added to reduce surface tension as well as to lower evaporation energy necessary to support subsequent image forming including laser patterning, as will be described in greater detail below. Small amounts of certain surfactants may be added to the dampening fluid as well. It should be recognized that, although the dampening fluid is described in the 212 Publication as being water-based, it should not be considered to be so limited.
Once the dampening fluid is metered onto the reimageable surface of the imaging member 110, a thickness of the dampening fluid may be measured using a sensor 125 that may provide feedback to control the metering of the dampening fluid onto the reimageable surface of the imaging member 110 by the dampening fluid subsystem 120.
Once a precise and uniform amount of dampening fluid is provided by the dampening fluid subsystem 120 on the reimageable surface of the imaging member 110, an optical patterning subsystem 130 may be used to selectively form a latent image in the uniform dampening fluid layer by image-wise patterning the dampening fluid layer using, for example, laser energy. The reimageable surface of the imaging member 110 should ideally be designed to absorb most of the laser energy emitted from the optical patterning subsystem 130 close to its surface to minimize energy wasted and to minimize lateral spreading of heat in order to maintain a high spatial resolution capability. Alternatively, an appropriate radiation sensitive component may be added to the dampening fluid to aid in the absorption of the incident radiant laser energy. While the optical patterning subsystem 130 is described above as being a laser emitter, it should be understood that a variety of different systems may be used to deliver the optical energy to pattern the dampening fluid.
The mechanics at work in the patterning process undertaken by the optical patterning subsystem 130 of the exemplary system 100 are described in detail with reference to
Following patterning of the dampening fluid layer by the optical patterning subsystem 130, the patterned layer over the reimageable surface of the imaging member 110 is presented to an inker subsystem 140. In the system described in the 212 Publication, as depicted in
The cohesion and viscosity of the inked image pattern residing on the reimageable surface of the imaging member 110 may be modified by a number of mechanisms. One such mechanism may involve the use of a rheology (complex viscoelastic modulus) control subsystem 150. The rheology control system 150 may form a partial crosslinking core of the ink on the reimageable surface, for example, to increase the cohesion of the ink relative to adhesion of the ink to the reimageable surface. Ink pre-conditioning mechanisms may include optical or photo curing, heat curing, drying, or various forms of chemical curing. Cooling may be used to modify rheology as well via multiple physical cooling mechanisms, as well as via chemical cooling.
The inked image is then transferred from the reimageable surface of the imaging member 110 to an image receiving medium substrate 114 using a transfer subsystem 160. The transfer occurs as the image receiving medium substrate 114 is passed through the transfer nip 112 between the imaging member 110 and an impression roller 118 such that the ink on the reimageable surface of the imaging member 110 is brought into physical contact with the image receiving medium substrate 114. Careful control of the temperature and pressure conditions at the transfer nip 112 may allow transfer efficiencies for the pre-conditioned ink from the reimageable surface of the imaging member 110 to the image receiving medium substrate 114 to be controlled. While it is possible that some dampening fluid may also wet the image receiving medium substrate 114, the volume of such a dampening fluid will be minimal, and will rapidly evaporate or be absorbed by the image receiving medium substrate 114.
Following the transfer of the inked image from the reimageable surface of the imaging member 110 to the image receiving medium substrate 114, any residual ink and/or residual dampening fluid must be removed from the reimageable surface, preferably without scraping or wearing the surface. An air knife 175 may be employed, for example, to remove residual dampening fluid from the reimageable surface. It is anticipated, however, that some amount of ink residue may remain. Removal of such remaining ink residue may be accomplished through use of some form of cleaning subsystem 170. The 212 Publication describes details of such a cleaning subsystem 170 including at least a first cleaning member such as a sticky or tacky member in physical contact with the reimageable surface of the imaging member 110. The sticky or tacky member may be used to remove the residual ink and any remaining small amounts the dampening fluid. The sticky or tacky member may then be brought into contact with a smooth cylinder to which residual ink may be transferred, the residue ink being subsequently stripped from the smooth cylinder by, for example, a doctor blade.
The 212 Publication details that, once cleaned, the reimageable surface of the imaging member 110 is again presented to the dampening fluid subsystem 120 by which a fresh layer of dampening fluid is supplied to the reimageable surface of the imaging member 110, and the process is repeated.
According to the above proposed architecture, variable digital data lithography has attracted attention in producing truly variable digital images in a lithographic image forming system.
Separate systems have been proposed for incorporating the above architecture into a conventional offset lithographic system. U.S. patent application Ser. No. 13/494,098 to Jia et al. (the 098 Application), entitled “Systems And Methods For Implementing Digital Offset Lithographic Printing Techniques,” filed Jun. 12, 2012, which is commonly assigned and the disclosure of which is incorporated herein by reference in its entirety, discloses examples of proposed multi-color variable data lithographic systems. The exemplary multi-color variable data lithographic system concepts disclosed in the 098 may include multiple individual color modules based on an objective of maximum reuse of a conventional lithographic architecture.
An additional cleaning unit 290 may be provided downstream of the transfer nip to clean residual ink and/or other debris from the surface of the intermediate transfer member 256 after the inked image is transferred to the image receiving medium substrate 280 at the transfer nip. The cleaning unit 290 may include a pressure cylinder 292, a sticky or tacky cylinder 294 and a smooth cylinder 296 or other configurations of relevant cleaning components.
Those of skill in the art will recognize that differing configurations of module elements, including, for example, providing multiple individual intermediate transfer members for the transfer of inked images to image receiving medium substrates employing differing numbers of individual modules with the same or different color inks may be included.
In the above-discussed examples of single-color variable digital data lithographic modules and multi-color variable digital data lithographic image forming systems, certain challenges arise that were not of concern in conventional lithographic systems. These challenges involve principally the need to increase levels of ink transfer efficiency from the reimageable surface to the intermediate transfer member and from the intermediate transfer member to the image receiving medium substrate for the reasons discussed above. In conventional lithographic printing, the inks are comparatively viscous and the inks tend to split at the image transfer nips leaving often as much ink with the ink donor surface as is transferred to the ink receiver surface at each nip. This challenge is exacerbated in the production of multi-level inked images where ink is transferred from the ink donor surface onto an already inked receiver surface.
It would be advantageous to optimize ink characteristics and ink transfer parameters in the proposed variable digital data lithographic image forming systems to promote high efficiency ink transfer from an ink donor surface to an ink receiver surface in order that, for example, excessive amounts of untransferred ink do not remain on the ink donor surface requiring extensive cleaning in the image forming system between cycles of a multi-color ink system.
Exemplary embodiments of the systems and methods according to this disclosure control characteristics of the inks and relative ink transfer parameters to promote high efficiency ink transfer in variable digital data lithographic image forming systems and devices.
Exemplary embodiments promote high ink transfer efficiencies in inked image transfer from the reimageable surface of the imaging member to the intermediate transfer body and then from the intermediate transfer body to the image receiving medium substrate.
Exemplary embodiments that include image on image transfer optimize the process of multiple layers of ink transfer from a plurality of reimageable surfaces in a plurality of individual ink color modules to an intermediate transfer member by necessarily controlling the transfer characteristics of the ink in order to (1) obtain highest levels of ink transfer, and (2) reduce potential for back transfer from the intermediate transfer member to the imaging members and their reimageable surfaces in the plurality of individual ink color modules comprising the multi-color image on image transfer system.
Exemplary embodiments may control individual colors of ink transfer by including combinations of a donor surface and a receiver surface in which a surface texture of the receiver surface is comparatively rougher than a surface texture of the donor surface thereby aiding in higher efficiency ink transfer between those surfaces.
In embodiments, when transferring multiple ink layers, a relationship between the tack (viscosity measure) between the first layer of ink and second or subsequent layers of inks must be according to a particular relationship as described in detail in this disclosure to promote highest levels of ink transfer while reducing potential for retacking of ink to the reimageable surface of the imaging member.
Exemplary embodiments modify the ink transfer scheme used in conventional offset lithography in which ink is transferred from one surface to another and typically splits in a condition where approximately half of the ink is transferred to the receiver surface and half of the ink remains with the donor surface. In embodiments, the disclosed schemes control characteristics (cohesiveness) of the ink to limit the possibility/likelihood of the ink splitting when being transferred from the donor surface to the receiver surface or from the donor surface to an ink layer already deposited on the receiver surface.
Exemplary embodiments may provide that almost all of the formed ink images on the reimageable surface of the imaging member and on the intermediate transfer member, e.g., in excess of 90%, are transferred to a next receiver surface.
Exemplary embodiments may include a unique multi-ink, single reimageable surface configuration for a variable digital data offset lithographic module for producing multi-color images on image receiving substrates that is particularly adaptable to the disclosed schemes. The color images on the receiver surface may be pre-conditioned or pre-cured between individual color applications in the unique multi-ink module to avoid back transfer.
These and other features, and advantages, of the disclosed systems and methods are described in, or apparent from, the following detailed description of various exemplary embodiments.
Various exemplary embodiments of the disclosed systems and systems and methods for optimizing a multi-color variable digital data offset lithographic image forming systems by controlling characteristic of a plurality of individual color inks to maximize ink transfer onto a substrate or onto other color ink layers in producing multi-color digital output images with a proposed variable digital data offset lithographic image forming system architecture will be described, in detail, with reference to the following drawings, in which:
The systems and methods for optimizing a multi-color variable digital data offset lithographic image forming system by controlling characteristics of a plurality of individual color inks to maximize ink transfer onto a substrate or onto other color ink layers in producing multi-color digital output images with a proposed variable digital data offset lithographic image forming system architecture according to this disclosure will generally refer to this specific utility or function for those systems and methods. Exemplary embodiments described and depicted in this disclosure should not be interpreted as being specifically limited to any particular configuration of the described elements, or as being specifically directed to any particular intended use. Any advantageous combination of schemes for modifying viscosity and/or rheology of a particular lithographic ink composition to promote high efficiency ink transfer is contemplated. Additionally, various configurations of one or more of an ink donor surface, an ink receiving surface, an imaging member, an intermediate transfer member and/or an image receiving medium substrate, as those components or elements may be understood to be employed in a variable digital data lithographic image forming systems, particularly where differences in surface textures of the ink donor surface and the ink receiver surface promote high transfer efficiencies for the various inks are contemplated to be included in the description below.
Specific reference, for example, to various configurations of offset lithographic printing devices, or proposed variable digital data lithographic image forming systems should not be considered as being limited to any particular configuration of those respective devices, as described and those references are intended to refer globally to a class of devices and systems that carry out what are generally understood as lithographic printing functions as those functions would be familiar to those of skill in the art.
As with the example shown in, and discussed above regarding,
Absent the systems and methods according to this disclosure, which promote increased relative transfer efficiencies in the proposed systems from donor surfaces to receiver surfaces, too much residual ink may be left on the donor surfaces (1) requiring excessive cleaning and/or (2) producing excessive residual ink waste.
Unlike a xerographic image forming process in which a varying electrical bias can be used to move charged toner images in a desired direction, the transfer of the lithographic inked images from the donor surface to the receiver surface requires consideration of the complex interactions discussed above. The control of the respective forces may promote inked image transfer from a reimageable surface of an imaging member to a surface of an intermediate transfer member and from the surface of the intermediate transfer member to a surface of an image receiving medium substrate, both relevant transfers being accomplished with high efficiency and with sufficient latitude.
Further, the control of the respective forces is intended to prevent relevant back transfer. There may be four layers of ink in a fourth transfer nip to the intermediate transfer member making the image at that point in the image forming process most susceptible to ink splitting and back transfer. With an understanding that the variable digital data lithographic image forming process is a rheology dominated process, the balances of relative adhesions and cohesions play a critical role promoting high efficiency ink transfer. The simple rule is:
Separately, a material for the intermediate transfer member may be carefully chosen. The material may first be chosen to promote release of the multi-layer inked image at the final transfer to the image receiving medium substrate. The selection of material may be, for example, from the classes of materials commonly known as silicones or fluoro-silicones, and those marketed under the trade name Viton®.
In addition, the ink layer/intermediate transfer surface adhesion interaction may be carefully tuned to satisfy the following four conditions:
As indicated above, one simple manner by which to achieve the above relative force parameters in a particularly-chosen current material set may be to change the relative surface roughness between the donor surface and the receiver surface. For example, similar surface materials can be used for both the reimageable surface of the imaging member and the surface of the intermediate transfer member in the variable digital data lithographic image forming system. The imaging member may have a relatively smoother (reimageable) surface, while the intermediate transfer member may have a comparatively rougher finish.
As the proposed variable digital data lithographic image forming process continues to mature, excellent image quality for the produced output images is being achieved with a smooth reimageable surface for the imaging member with vaporized dampening fluid, and excellent release is also demonstrated with a textured (rough) surface.
System latitude may be particularly challenging for multiple ink layers, including increased concerns with back transfer at later ink transfer layers, e.g., in a third and a fourth layer of ink transfer from the imaging member to the intermediate transfer member, due to the significantly weakened ink layer cohesion because of the increased thickness. Here, it may be most appropriate to implement rheological conditioning processes between the transfers to improve the ink layer cohesion. These rheological conditioning processes may include one or more of known techniques including ultraviolet pre-curing, surface evaporation, layer heating or other like methods.
In experiments, a smooth fluorosilicone material (Nusil®, flow coated) was used as the reimageable surface for the imaging member, and a textured variant of the same fluorosilicone material (Nusil®, Agfa texture) was used as the intermediate transfer member. A particular variable digital data lithographic ink (formulation C33) was applied to the reimageable surface with an anilox roll. This combination produced nearly 100% first transfer of the ink from the reimageable surface to a surface of the intermediate transfer member, and greater than 90% second transfer from the image transfer member to Lustrogloss® paper as the image receiving medium substrate.
Advantages of the disclosed schemes include: (1) simplified use of less expensive media handling components; (2) improved color registration achieved independent of media handling adjustments and without using “trial” sheets; (3) greater system architectural flexibility with a wide array of possible intermediate configurations; and (4) isolation of each imaging member and associated subsystems comprising each imaging module from image receiving medium related damage and debris.
According to the exemplary embodiment 500 shown in
An image formed of one or more ink layers on the intermediate transfer member 550 according to the details set forth below may be transferred to an image receiving medium substrate 570 at a transfer nip formed between the intermediate transfer member 550 and an impression roller 560. A separate intermediate transfer member cleaning unit 555 may be provided to clean residual ink and/or debris from the intermediate transfer member 550 after image transfer to the image receiving medium substrate 570 at the transfer nip. The cooperating textures of the reimageable surface of the imaging member 510, a surface of the intermediate transfer member 550 and a surface of an image receiving medium substrate 570 may enable high-efficiency in high fidelity ink transfer, e.g., in excess of 90%, from the reimageable surface of the imaging member 510 to the surface of the intermediate transfer member 550 and then, in turn, from the surface of intermediate transfer member 550 to all types of image receiving medium substrates, such as the exemplary image receiving medium substrate 570 shown in
In operation, downstream of a transfer nip between imaging member 510 and the intermediate transfer member 550, a cleaning system 545 may be provided for cleaning residual ink and debris from the reimageable surface of the imaging member 510. A metered amount of a dampening fluid, as described above, may be applied to the reimageable surface using a dampening fluid supply and metering unit 515. An optical patterning unit 520 may produce optical patterned images in the dampening fluid bathed reimageable surface of the imaging member 510. The optical patterning unit 520 may comprise a laser patterning device for projecting laser energy onto the reimagaeable surface, according to the methods described above. As shown in
The multi-color inker 530 may operate in conjunction with the imaging member 510 on multiple cycles as follows. Four inkers 532,534,536,538 may be available in the multi-color inker 530. Upon commencement of the imaging operation, the impression roller 560 may be disengaged in a manner such that no transfer nip is formed with the intermediate transfer member 550. In like manner, at this stage in the imaging operation, the intermediate transfer member cleaning unit 555 may also be disengaged so as to not contact the surface of the intermediate transfer member 550.
In a first color cycle of the imaging member 510, a first color ink supply 532 may be brought into contact engagement with the patterned reimageable surface of the imaging member 510. The first color ink will be deposited on the reimageable surface creating a first color inked image on the patterned reimageable surface. The rheology of the first color ink may be modified by the rheology control or conditioning unit 540. The first color inked image may then be transferred from the reimageable surface of the imaging member 510 to the surface of the intermediate transfer member 550 at the transfer nip formed therebetween.
In a second color cycle of the imaging member 510, a second color ink supply 534 may be brought into contact engagement with the patterned reimageable surface of the imaging member 510. The second color ink will be deposited on the reimageable surface creating a second color inked image on the patterned reimageable surface. The rheology of the second color ink may be modified by the rheology control or conditioning unit 540. The second color inked image may then be transferred from the reimageable surface of the imaging member 510 to the surface of the intermediate transfer member 550 at the transfer nip formed therebetween over the first color inked image.
In a third color cycle of the imaging member 510, a third color ink supply 536 may be brought into contact engagement with the patterned reimageable surface of the imaging member 510. The third color ink will be deposited on the reimageable surface creating a third color inked image on the patterned reimageable surface. The rheology of the third color ink may be modified by the rheology control or conditioning unit 540. The third color inked image may then be transferred from the reimageable surface of the imaging member 510 to the surface of the intermediate transfer member 550 at the transfer nip formed therebetween over the first and second color inked images.
In a fourth color cycle of the imaging member 510, a fourth color ink supply 538 may be brought into contact engagement with the patterned reimageable surface of the imaging member 510. The fourth color ink will be deposited on the reimageable surface creating a fourth color inked image on the patterned reimageable surface. The rheology of the fourth color ink may be modified by the rheology control or conditioning unit 540. The fourth color inked image may then be transferred from the reimageable surface of the imaging member 510 to the surface of the intermediate transfer member 550 at the transfer nip formed therebetween over the first, second and third color inked images.
With the four-color inked image formed on the intermediate transfer member 550 in this embodiment, the impression roller 560 may be moved to contact the intermediate transfer member 550 to form a transfer nip via which an image receiving medium substrate 570 may be conveyed for image transfer. The four-color inked image may be transferred from intermediate transfer member 550 to the image receiving medium substrate 570 at the transfer nip. The intermediate transfer member cleaning unit 555 may be moved to engage the surface of the intermediate transfer member 550 to clean any residual ink or debris from the surface of the intermediate transfer member 550.
As a trail edge of the image receiving medium substrate passes the transfer nip between the intermediate transfer member 550 and the impression roller 560, the impression roller 560 may be disengaged in preparation for a next image forming operation. As a trail edge of a residual image on the surface of the intermediate transfer member 550 passes the intermediate transfer member cleaning unit 555, the intermediate transfer member cleaning unit 555 may again be disengaged so as to not contact the surface of the intermediate transfer member 550 in preparation for the next image forming operation.
This discussion is not intended to limit multi-color inker 530 to any particular configuration or design. It should be recognized that there are many ink supply configurations as alternatives that could be proposed.
The exemplary control system 600 may include an operating interface 610 by which a user may communicate with the exemplary control system 600 for directing image forming operations, including the forming of multi-color output images, in a variable digital data lithographic image forming system such as those described above via one or more digital lithography system control devices 660. The operating interface 610 may be a locally accessible user interface associated with the image forming system, which may be configured as one or more conventional mechanisms common to control devices and/or computing devices that may permit a user to input information to the exemplary control system 600. The operating interface 610 may include, for example, a conventional keyboard, a touchscreen with “soft” buttons or with various components for use with a compatible stylus, a microphone by which a user may provide oral commands to the exemplary control system 600 to be “translated” by a voice recognition program, or other like device by which a user may communicate specific operating instructions to the exemplary control system 600. The operating interface 610 may be a part or a function of a graphical user interface (GUI) mounted on, integral to, or associated with, the image forming system with which the exemplary control system 600 is associated.
The exemplary control system 600 may include one or more local processors 620 for individually operating the exemplary control system 600 and for carrying out operating functions in the image forming system. Processor(s) 620 may include at least one conventional processor or microprocessor that interprets and executes instructions to direct specific functioning of the exemplary control system 600 and an associated image forming system.
The exemplary control system 600 may include one or more data storage devices 630. Such data storage device(s) 630 may be used to store data or operating programs to be used by the exemplary control system 600, and specifically the processor(s) 620. Data storage device(s) 630 may be used to store information regarding individual operating characteristics of the image forming and specific components for controlling the rheology of multiple ink layers that may be used to form an output image from the image forming system. These stored schemes may control all operations of the image forming system. The data storage device(s) 630 may include a random access memory (RAM) or another type of dynamic storage device that is capable of storing updatable database information, and for separately storing instructions for execution of system operations by, for example, processor(s) 620. Data storage device(s) 630 may also include a read-only memory (ROM), which may include a conventional ROM device or another type of static storage device that stores static information and instructions for processor(s) 620. Further, the data storage device(s) 630 may be integral to the exemplary control system 600, or may be provided external to, and in wired or wireless communication with, the exemplary control system 600.
The exemplary control system 600 may include at least one data output/display device 640, which may be configured as one or more conventional mechanisms that output information to a user, including, but not limited to, a display screen on a GUI of the image forming system with which the exemplary control system 600 may be associated. The data output/display device 640 may be used to indicate to a user a status of an image forming operation in the image forming system.
Where appropriate, the exemplary control system 600 may include at least one external data communication interface 650 by which the exemplary control system may communicate with the image forming system when the exemplary control system 600 is mounted remotely from, and in wired or wireless communication with, the associated image forming system.
All of the various components of the exemplary control system 600, as depicted in
It should be appreciated that, although depicted in
The disclosed embodiments may include methods for controlling characteristics and functions of variable digital data lithographic image forming.
In Step S7100, residual ink, dampening fluid and/or other debris may be removed from surfaces of the imaging member and the intermediate transfer member in preparation for a variable digital data lithographic image forming cycle in a variable digital data offset lithographic image forming system. Operation of the method proceeds to Step S7200.
In Step S7200, an impression roller and an intermediate transfer member cleaning unit may be disengaged from the intermediate transfer member to prepare the intermediate transfer member to receive multiple colors of ink in layers. Operation of the method proceeds to Step S7300.
In Step S7300, a consistent layer of dampening fluid may be deposited on the imaging surface of the imaging member. Operation of the method proceeds to Step S7400.
In Step S7400, a digital image may be developed in the layer of dampening fluid deposited on the imaging surface of the imaging member using an optical imaging device such as a laser imaging device. Operation of the method proceeds to Step S7500.
In Step S7500, a first color ink layer may be applied to the developed dampening fluid layer digital image on the imaging surface of the imaging member from a multiple color inking system. Operation of the method proceeds to Step S7600.
In Step S7600, the rheology (viscosity or cohesion) of the first color ink layer forming the first color inked image on the imaging surface of the imaging member may be modified by using, for example, a rheology adjusting system that may pre-condition or partially cure the deposited first color ink layer in a manner that will aid in maximizing the ink transfer efficiency from the imaging member to the intermediate transfer member. Operation of the method proceeds to Step S7700.
In Step S7700, the first color inked image may be transferred from the imaging surface of the imaging member to the intermediate transfer member. Operation of the method proceeds to Step S7800.
In Step S7800, at least one second color ink layer may be applied to the developed dampening fluid digital image on the imaging surface of the imaging member from a multiple color inking system. Operation of the method proceeds to Step S7900.
In Step S7900, the rheology of the at least one second color ink layer forming the at least one second color inked image on the imaging surface of the imaging member may be modified, as above. Operation of the method proceeds to Step S8000.
In Step S8000, the at least one second color inked image may be transferred from the imaging surface of the imaging member to the intermediate transfer member over the previously transferred first color inked image.
Transfer of subsequent colors of inks to form separate color inked images on the intermediate transfer member may be completed in the manner outlined above until all available color inked images are deposited in layers on the intermediate transfer member. Operation of the method proceeds to Step S8100.
In Step S8100, the impression roller and the intermediate transfer member cleaning unit may be reengaged with the surface of the intermediate transfer member to form transfer and cleaning nips, respectively. Operation of the method proceeds to Step S8200.
In Step S8200, the multiple color inked image formed on the surface of the image transfer member may be transferred to an output image receiving medium at the transfer nip formed between the intermediate transfer member and the impression roller. Operation of the method proceeds to Step S8300.
In Step S8300, the image receiving medium substrate, with the variable digital data lithographic image formed thereon, may be output from the image forming system. Operation of the method proceeds to Step S8400, where operation of the method ceases.
The above-described exemplary systems and methods reference certain conventional components to provide a brief, general description of suitable image forming means by which to carry out variable digital data lithographic image forming. Those skilled in the art will appreciate that other embodiments of the disclosed subject matter may be practiced with many types of image forming elements common to lithographic image forming systems in many different configurations.
The exemplary depicted sequence of executable instructions represents one example of a corresponding sequence of acts for implementing the functions described in the steps. The exemplary depicted steps may be executed in any reasonable order to carry into effect the objectives of the disclosed embodiments. No particular order to the disclosed steps of the method is necessarily implied by the depiction in
Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the disclosed systems and methods are part of the scope of this disclosure.
It will be appreciated that a variety of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
