The adoption of digital print continues to expand due in large part to the improvements in existing technologies as well as the development of new technologies that offer increasing levels of productivity, image quality, and economy. Eastman Kodak Company, a recognized leader in conventional and digital printing technologies, provides unified workflow solutions for a large number of diverse applications. In the area of inkjet printing, Kodak continues to pioneer ultra-high productivity inkjet technology for applications including, but not limited to, commercial, transactional, direct mail, packaging, and book publishing. Recent advancements in the ability to precisely control the instabilities in thermally stimulated microjets, coupled with advancements in MEMS technology, computer modeling of complex microfluidic systems, ink technology, and ink-substrate interactions, enabled the development and subsequent commercialization of a new continuous inkjet technology. This technology offers extremely high productivity with high image quality on a wide variety of substrates while maintaining a low total ownership cost. This technology, referred to as “KODAK Stream Inkjet Technology (or “Stream”),” forms the basis of a technology platform that is highly extensible, allowing participation in a broad range of markets that can effectively utilize high-speed digital print production. This paper will discuss the opportunities as well as the challenges of digital print and describe how Stream technology will play a significant role in this transformation.

Print manufacturing is a make-to-order process; it converts customers' print demands into shipped print products such as books, calendars, and stationeries. Its service level objectives are usually dominated by the on-time delivery constraint. Given the existing resource makeup, the business objective of the print service providers is to drive up the throughput to dilute the fixed cost and maximize the profit while guarantees the quality of service.The print manufacturing process outlined above, in particular on-demand digital print, cannot be simply treated as a standard manufacturing activity. The highly variable and dynamic nature of the job mix combined with personalized customer requirements results in numerous combinations of factory configuration and business philosophy. This has been identified as a key reason that hinders the print productivity growth. In this paper we report our recent development of a simulation platform of digital print manufacturing operations adopting an open-source electronic design automation tool, and shed light into paths towards implementing a lean print manufacturing paradigm.

Toner cloud beam (TCB) is a novel toner-based printing method that employs conductive toner. Toner dots are formed directly on paper in the TCB method. The toner beam is controlled by applying a pulsed voltage to a pair of aperture electrodes. The pulse control characteristics of the toner beam are important in the TCB method. The dot formation dependence on the electrode voltages is investigated experimentally and the relationship between the dot size and the pulse duration is obtained. An enlarged model with an aperture diameter of 0.5 mm is used to confirm that dots are formed in less than 10⁻⁴ s. The toner speed at a toner cloud generation voltage of 550 V is estimated to be 4.1 m/s.

The PSP design technique that we present is, at its core, the generalization of structured job data via neural network learning techniques. While current PSP design focuses on the optimal use of capital equipment as its primary motivation, the essential competitive advantage of digital presses and workflow is its ability to adapt to different types of content with highest robustness to failure and minimal component-level change; these characteristics are also the same for neural networks. By generalizing the fulfillment order with a representative neural network, we can automatically identify redundancy between jobs and optimize the infrastructure for a particular content mix. By adaptively changing the neural network in the face of different job fulfillment demands, the neural network can also indicate how to transform the current PSP infrastructure to handle a new mix of jobs requests. We apply a structural learning technique based on a subset of Hidden Markov Models, Directed Acyclic Graphics, and then map these neural structures into print shop infrastructure. We will demonstrate our results with real world PSP data, and compare and contrast the current real world PSP design with its neurally designed counterpart.

This article explores the possibility of using a laser to remove toner-print from office paper. Removal of print would allow paper to be re-used instead of being recycled or disposed into a landfill. This might reduce climate change gas emissions per tonne of office paper by between 45% and 95%. Although there is little previous research on the area, a number of related articles on paper conservation methods using laser radiation can be found in literature. Different authors have studied the effects of laser energy on blank paper and its application for cleaning soiled paper. However, this study examines toner-print removal from paper by laser ablation. In this article a laser in the visible range is applied to a single toner-paper combination with a range of energy fluences. Results are evaluated by means of colour measurements under the L*a*b* colour space and SEM images. Analysis of the samples reveals that there are parameters under which it is possible to remove toner from paper without causing significant discolouration or damage to the substrate. This means that it is technically possible to remove toner-print for paper reuse.

We introduce two novel methods for accurately predicting the conversion function from digital input to printed dot area. This conversion function is substantial for dot gain compensation. Dot gain compensation (“press linearization”) is aimed at keeping the print color consistent while the press physical parameters drift. To achieve good and consistent print quality, this procedure should be done often. However, since it requires the printing of special jobs with color patches, it consumes both time and paper. This procedure is even more unwieldy in web presses that print on rolls of paper. The goal of this work is to achieve good print quality with much fewer print interruptions.The first method is based on a physical model and the second is built on a complete heuristic model. Both methods use the digital data and a small set of measurements as an input. These methods provide the possibility to accurately and directly predict the conversion function. We further discuss the concept of a full physically predictive method. The methods were tested on an HP-Indigo digital press but the concept is applicable to any printer.

Simulations of the jetting of Newtonian fluids from drop-ondemand print heads show that the radial jet pinch-off region, which may lie inside the nozzle, is strongly affected by the fluid viscosity over the range of values that are commonly used. Jet profiles beyond the nozzle exit predicted in these simulations match previously published high resolution images very well and validate the code used. The simulations show that the radial velocity at the minimum radius in the pinch-off region falls exponentially soon after neck formation but then approaches a speed near that predicted theoretically for filament rupture.The overall jet length is primarily controlled by the slow speed of radial pinch-off. Towards the final break-off time, competition between the original radial minimum and a developing second radial minimum can alter the flow conditions towards symmetry. The simulations also explain why visible jets are shaped like truncated cones. Pinch-off occurs typically within one nozzle radius of the nozzle exit, and while it may be located within the nozzle region, another radial minimum also forms outside the nozzle, close to the exit for low viscosity fluids but well beyond it for higher viscosity fluid. The radial collapse follows a power law with time, with the power-law index n varying between the value of n=2/3 expected for an inviscid fluid and n=1 law expected for a viscous fluid. The transition in behavior occurs at a viscosity of ∼20 mPa s, which is within the range of ∼10–40 mPa s typical of most DoD inks formulations.

As Print Service Providers (PSPs) become more digital and move toward digital presses and digital workflows, a technique from Electronic Design Automation called multi-level simulation can simultaneous analyze and recreate interplay of operations, document design, and lean manufacturing with the next generation of PSPs. Multi-level simulation recognizes that hierarchical design has different levels of abstraction and each layer of abstraction has its own design language to search its respective design space. However, multi-level simulation integrates these multiple heterogeneous and overlapping layers of design abstraction for an optimal system goal. This goal for silicon chip is power, clock speed, or die size; the goal for a digital PSP is, ultimately, operational efficiency in the face of variability of job fulfillment. Multi-level simulation of a PSP bind together the competing goals of manufacturing efficiency, operational overhead, and content fulfillment capabilities; we submit there are three abstraction layers for these PSP goals: job for routing both inter-PSP and intra-PSP, PDL transformations for workflow, and image for visual inspection. Using Ptolemy EDA tools as a backbone, we will demonstrate this approach on such complex, high-value digital workflows such as security documents and automated print quality analysis, in terms of higher operational efficiency and profit per pages.

The effects of nozzle defects on the behaviour of drops ejected from drop-on-demand print-heads were studied. Nozzles in two types of commercial print-heads were modified with two different micromachining techniques: focused ion beam (FIB) milling and pulsed laser micromachining. Nozzles were modified by producing single or multiple notches on their edges. The studies focused on the volume, speed and direction of travel of the drops. Fifteen different types of geometrical defects on 128 nozzles were studied. Shadowgraph images captured with short high time resolution were used to determine the drop size, speed and trajectory from the same nozzles before and after modification. The results indicate that geometrical defects up to ∼100 μm² at the front (exit) face of a 50 μm diameter nozzle do not cause any significant variation on the behaviour of these nozzles but that defects at the back (entry) of the nozzle can have a major effect on the direction of jetting.

Exposure of some digital print types to high humidity can cause image colorant migration resulting in image density changes, color shift, blurring and loss of detail. The purpose of this study was to quantify the potential for colorant bleed during short-term exposures to high humidity conditions in order to develop care and use guidelines for museums, libraries and archives that may collect large numbers of these materials including many of high monetary value. Most previous work has focused on image effects, but this project also includes tests for damage to text-based documents. The potential for bleed both parallel and perpendicular to the printer paper feed direction was examined. A variety of digitally printed materials, including inkjet, electrophotographic, and dye sublimation were exposed to high humidity conditions for two and four weeks. Results are reported as Delta E for a checkerboard target, change in width for lines both parallel and perpendicular to the paper feed direction, as well as text readability which was assessed visually. The relative sensitivities of the materials are ranked and compared to the sensitivities of traditionally printed offset lithography and chromogenic photo materials.