Graphic Communication Copyright (c) 2013 California Polytechnic State University All rights reserved. http://digitalcommons.calpoly.edu/grc_fac Recent documents in Graphic Communication en-us Thu, 16 May 2013 09:47:38 PDT 3600 Study of Co-Solvent Effects on Stickies Removal in Supercritical Fluid Extraction http://digitalcommons.calpoly.edu/grc_fac/22 http://digitalcommons.calpoly.edu/grc_fac/22 Wed, 23 Feb 2011 14:15:33 PST Using supercritical carbon dioxide to remove stickies in recycling fibers is studied at laboratory scale. Supercritical carbon dioxide is the most environmental friendly supercritical fluid widely used in extraction process. This study includes co-solvent effect on sticky compounds removal by using supercritical carbon dioxide extraction. The sticky compounds are dispensed onto fibers, and then extracted using supercritical carbon dioxide and co-solvent in order to study the efficiency of stickies removal. The results show that supercritical carbon dioxide can remove most sticky compounds such as paraffin wax, polyethylene wax, polyvinyl acetate, polystyrene butadiene. It is demonstrated that with co-solvent, the extraction efficiency increases considerably under the same extraction conditions.

]]> Xiaoying Rong et al. Single Curved Fiber Sedimentation Under Gravity http://digitalcommons.calpoly.edu/grc_fac/21 http://digitalcommons.calpoly.edu/grc_fac/21 Wed, 23 Feb 2011 14:15:32 PST Dynamics of single curved fiber sedimentation under the gravity are simulated by using lattice Boltzmann method. The results of migration and rotation of the curved fiber at different Reynolds numbers are reported. The results show that the rotation and migration processes are sensitive to the curvature of the fiber.

]]> Xiaoying Rong et al. Gravure Printability From Laser and Electromechanically Engraved Cylinder http://digitalcommons.calpoly.edu/grc_fac/20 http://digitalcommons.calpoly.edu/grc_fac/20 Wed, 23 Feb 2011 14:15:31 PST Gravure printability comparison of laser engraved and electromechanically engraved cylinders was done on five different substrates. Ink transfer was less reduced on laser print than electromechnaical when printed without electrostatic assist. Print mottle was significantly lower and yellow, magenta and black laser engraved images, while cyan print from laser engraved cylinder had higher mottle on some substrates (SCB, SCA and freesheet). Overall, the print quality than that from the electromechanically engraved one.

]]> Xiaoying Rong et al. G7 Method for Indigo Press Calibration and Proofing http://digitalcommons.calpoly.edu/grc_fac/19 http://digitalcommons.calpoly.edu/grc_fac/19 Fri, 10 Dec 2010 09:15:29 PST G7 is a method originally developed for calibrating commercial offset press. Instead of controlling solid ink density (SID) and tone value increase (TVI), the G7 method introduces gray balance control as the key to achieve consistent color reproduction. The gray patches are quantified by CIE L*a*b* values. Inks used in conventional offset printing and Indigo printing are different in ink/toner pigments and ink setting/drying mechanism. Based on gray balance, the G7 method is believed to be valid for calibrating digital printing and other conventional printing processes. This study focused on the quality of color reproduction with the G7 method, and compared to the quality of direct ICC profile method. The results showed that the G7 method could be applied to toner-based printing process. The G7 method could improve gray balance and color gamut.

]]> Xiaoying Rong G7™ Method for Flexographic Press Calibration http://digitalcommons.calpoly.edu/grc_fac/18 http://digitalcommons.calpoly.edu/grc_fac/18 Fri, 10 Dec 2010 09:15:27 PST The purpose of this study is to apply the G7 method for calibration on a four-color flexographic press. G7 controls and calibrates a press using colorimetric values rather than tone value increase. Two press runs were completed to calibrate a flexographic press. The first press run provided data for creating a control curve called Neutral Print Density Curve (NPDC) for the press run with a specific combination of inks and substrate. The printed P2P target was used to build the RIP curve and cutback the digital file. The calibrated plates then ran for the second time to check the efficiency of calibration. By applying the NPDC curve, the second press run produced better neutral colors visually.

]]> Michael Bayard et al. The Study of Missing Dots of Electromechanical and Laser Engraved Cylinders http://digitalcommons.calpoly.edu/grc_fac/17 http://digitalcommons.calpoly.edu/grc_fac/17 Fri, 10 Dec 2010 09:15:26 PST According to the previous study, the printability of electromechanical engraved cylinder and laser engraved cylinder were different in terms of density, tone reproduction and mottle. In this study, the missing dots of two different engraved cell types were investigated. It showed that different cell structures had strong effect to ink transferring and the characteristics of missing dots. Lasers engraved cells were less affected by ESA (electrostatic assist). When there was no ESA applied, the laser engraved cells showed less missing dot area, which indicated better ink release from spherical shaped cells. ESA had more effects to coated substrates than supercalendered substrates.

]]> Xiaoying Rong et al. A Study of PLA Printability with Flexography http://digitalcommons.calpoly.edu/grc_fac/16 http://digitalcommons.calpoly.edu/grc_fac/16 Fri, 10 Dec 2010 09:15:24 PST Most products are boxes, bottles and bags. The printability of biodegradable film has not been fully investigated. This study tested the printability on clear and white Polylactic acid (PLA) films, and compared the print qualities to common packaging films like Polypropylene (PP), Polyethylene terephthalate (PET). Water-based flexo ink was used to test printability on PLA films. The influence of anilox roll and plate screen ruling was also considered. The print qualities were reported as dot shape, tone reproduction, and mottle. This study showed that biodegradable films could achieve similar quality compared to common packaging films. While printed at different screen rulings, clear PLA showed the highest dot gain and white PLA showed the lowest. All tested films appeared to have similar quality in keeping dot shape. In terms of mottle, white PLA appeared to be the worst among the four tested films.

]]> Xiaoying Rong et al. Quantitative Analysis of ICC Profile Quality for Scanners http://digitalcommons.calpoly.edu/grc_fac/15 http://digitalcommons.calpoly.edu/grc_fac/15 Fri, 10 Dec 2010 09:15:21 PST ICC profiling software is widely used in the graphic arts industry. The quality of a scanner profile created by profiling software using a single training target is discussed. A more stringent quantitative analysis of the profile quality is proposed. Different targets from different photo paper manufactures are used as the testing targets to compare the quality of the profiles. A grayscale was also used for testing the ability of profiling software to preserve gray balance. The results show that profiling software can generate apparently high quality profile for the training targets. However, the profile of one target assigned to the scan of other targets, used as originals, does not confirm this accuracy. Additionally, the RMS ΔE values of grayscale assigned profiles are higher than the RMS ΔE values of scanned targets assigned the same profile.

]]> Xiaoying Rong et al. Single Curved Fiber Sedimentation Under Gravity http://digitalcommons.calpoly.edu/grc_fac/14 http://digitalcommons.calpoly.edu/grc_fac/14 Mon, 01 Nov 2010 16:18:36 PDT Dynamics of single curved fiber sedimentation under gravity are simulated by using the lattice Boltzmann method. The results of migration and rotation of the curved fiber at different Reynolds numbers are reported. The results show that the rotation and migration processes are sensitive to the curvature of the fiber.

]]> Xiaoying Rong et al. A Study Of Instruction In Applied Mathematics: Student Performance And Perception http://digitalcommons.calpoly.edu/grc_fac/13 http://digitalcommons.calpoly.edu/grc_fac/13 Fri, 02 Jul 2010 09:02:44 PDT The purpose of this study was to examine the performance of high school students completing applied mathematics 1 and applied mathematics 2 courses based principally on the CORD Applied Mathematics curriculum in four Missouri school districts. Complete data sets were obtained from 254 students. A general linear model analysis of covariance procedure was used to determine if differences existed in mean scores among students in applied mathematics 1, applied mathematics 2, and a control group of algebra 1 students. Students were tested using the Pre-algebra/algebra portion of the P-ACT+ and the Work Keys Applied Mathematics assessments. Student attitudes toward math as a school subject were also assessed. Students completing applied math 2 were found to make progress comparable to those completing algebra 1. Students enrolled in applied math classes had similar attitudes toward math as algebra students despite having less previous success with math.

]]> Malcolm G. Keif et al. An Educator's Drupa Experience http://digitalcommons.calpoly.edu/grc_fac/12 http://digitalcommons.calpoly.edu/grc_fac/12 Fri, 02 Jul 2010 09:02:42 PDT On May 9, 2004, I boarded a flight to Düsseldorf, Germany, to attend drupa with some of my colleagues. The following days p roved to be a fabulous opportunity to network and learn about the greatest innovations in printing and, specifically, gravure. A portion of my trip was funded by the Gravure Education Foundation, to whom I express great appreciation .

]]> Malcolm G. Keif Identifying High-Volume Printing Processes http://digitalcommons.calpoly.edu/grc_fac/11 http://digitalcommons.calpoly.edu/grc_fac/11 Fri, 02 Jul 2010 09:02:40 PDT Printing professionals frequently examine printing to see how pieces were produced. They break out loupes and look at the dots. Is it offset or gravure? How about flexo? It is important to be able to distinguish among printing processes through examination in order to determine the key variables to control for quality printing. Further, expertise is established and confidence built when a professional can determine how something is printed.

]]> Malcolm G. Keif et al. Cal Poly Hosts Graphic Arts Educators Conference http://digitalcommons.calpoly.edu/grc_fac/10 http://digitalcommons.calpoly.edu/grc_fac/10 Fri, 02 Jul 2010 09:02:38 PDT Cal Poly State University in San Luis Obispo, Calif. hosted the International Graphic Arts Education Association (IGAEA) annual conference this summer, bringing together more than 80 educators to network, learn about the latest trends in graphic communications education and generally upgrade their skills.The conference took place over five days from July 30 to August 3, 2006 and included a number of general sessions as well as prepress, press,and digital media breakout sessions. The general sessions were conducted by author David Blatner,Adobe Principal Scientist Jim King, and Sappi’s Daniel Dejan.

]]> Malcolm Keif Why Aren't We Leaner in the United States? http://digitalcommons.calpoly.edu/grc_fac/9 http://digitalcommons.calpoly.edu/grc_fac/9 Fri, 02 Jul 2010 09:02:36 PDT Lean manufacturing has certainly been a hot topic lately for flexo printers and converters. It is rare to attend a conference or look through a trade magazine without seeing the subject as a central focus. Lean seems mysterious, almost Zen-like, partly because we use Japanese terms like muda, kanban, and kaizen instead of just using English translations. For many, we are just getting familiar with the concepts of Lean. Waste identification and reduction are certainly primary themes. Just-in-Time, 5S, Small-lot Production, and Setup Reduction are all recognizable Lean components. Some have seen improvements in their costs and efficiency, but others have been frustrated with their ability to sustain improvements.

So, it begs the questions: Is Lean just another fad? If not, why don't we see the big improvements sustained over long periods as promised? Is this something that only works in Japan? Just how Lean are we in the United States?

]]> Malcolm Keif Recruiting Gen X and Millennial Employees to Grow Your Business http://digitalcommons.calpoly.edu/grc_fac/8 http://digitalcommons.calpoly.edu/grc_fac/8 Fri, 02 Jul 2010 09:02:33 PDT For graphic communication companies, recruiting talented personnel will continue to be a key to success in upcoming years. One characteristic common among great businesses— regardless of industry—is a strong culture and a capable workforce. With so much attention given to JDF and the digital smart factory, one might conclude that a strong workforce can be substituted with technology. That couldn’t be further from the truth. Businesses that position themselves for growth are focusing on building a dynamic business culture for understanding and recruiting today’s employees.

]]> Malcolm Keif et al. Why Lean isn't Working in the Print Industry, and What You Should be Doing About It! http://digitalcommons.calpoly.edu/grc_fac/7 http://digitalcommons.calpoly.edu/grc_fac/7 Fri, 02 Jul 2010 09:02:29 PDT Change does not come easily for the print industry. Actually, strike that. Change does not come easily for most industries. There are a wide variety of reasons why people, companies, and industries do not embrace change. Without a willingness to change, companies get stuck in patterns that prevent them from not only progressing operationally, but also culturally.

]]> Malcolm G. Keif et al. Estimating and Job Costing Digital Printed Matter http://digitalcommons.calpoly.edu/grc_fac/6 http://digitalcommons.calpoly.edu/grc_fac/6 Fri, 02 Jul 2010 09:02:27 PDT Malcolm G. Keif Cost-Estimating For Commercial Digital Printing http://digitalcommons.calpoly.edu/grc_fac/5 http://digitalcommons.calpoly.edu/grc_fac/5 Fri, 02 Jul 2010 09:02:25 PDT The purpose of this study is to document current cost-estimating practices used in commercial digital printing. A research study was conducted to determine the use of cost-estimating in commercial digital printing companies. This study answers the questions: 1) What methods are currently being used to estimate digital printing? 2) What is the relationship between estimating and pricing digital printing? 3) To what extent, if at all, do digital printers use full-absorption, all-inclusive hourly rates for estimating? Three different digital printing models were identified: 1) Traditional print providers, who supplement their offset presswork with digital printing for short-run color and versioned commercial print; 2) "Low-touch" print providers, who leverage the power of the Internet to streamline business transactions with digital storefronts; 3) Marketing solutions providers, who see printing less as a discrete manufacturing process and more as a component of a complete marketing campaign. Each model approaches estimating differently. Understanding and predicting costs can be extremely beneficial. Establishing a reliable system to estimate those costs can be somewhat challenging though. Unquestionably, cost-estimating digital printing will increase in relevance in the years ahead, as margins tighten and cost knowledge becomes increasingly more critical.

]]> Malcolm G. Keif Making Superior Plates Every Time http://digitalcommons.calpoly.edu/grc_fac/4 http://digitalcommons.calpoly.edu/grc_fac/4 Fri, 02 Jul 2010 09:02:21 PDT Flexo plates are a critical component of the printing system. Printing is a system—viewing platemaking in isolation doesn’t address the total print process. A system has multiple components that interact with each other and influence the performance of each. Great plates with the wrong anilox rolls offer nothing to improve quality. Likewise, great plates made from a poorly prepared file help little to produce an outstanding final product. So, looking upstream and downstream is necessary to ensure your plates are supporting the total printing system.

Superior printing plates…

•have sufficient resolution for the graphics to be reproduced on the substrate for the job (paper, film, foil, etc).

•are produced to optimize press and ink performance.

•are made in a controlled and repeatable manner. Let’s look at several important factors to making great plates.

Let's look at several important factors to making great plates.

]]> Malcolm G. Keif Pre-Registering Print Cylinders on Press http://digitalcommons.calpoly.edu/grc_fac/3 http://digitalcommons.calpoly.edu/grc_fac/3 Fri, 02 Jul 2010 09:02:18 PDT Those who study lean manufacturing know that waste comes in many forms. We must remind ourselves that anything that does not produce exactly what the customer values, when it is needed, is a wasteful operation. Makereadies, or press setups, are wasteful, at least in the eyes of our customers. Reducing press setup time is critical for improving customer value and making the printer more competitive on short-runs while increasing overall productivity. Even though make-ready time is built into an estimate, the bottom line is that it isn’t something a customer is delighted about paying for. Reducing makeready time, therefore, becomes a strategy that improves competitiveness in the marketplace.

]]> Malcolm G. Keif