Anilox Roll Cleaning Essential to Effective Ink Delivery

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by Flexo Concepts

Anilox_Cleaner_300X298You spend plenty of time selecting the correct anilox roll for a job. Careful consideration goes into line screen, cell geometry and cell volume in order to guarantee that a precise amount of ink or coating is delivered to the substrate. Aniox roll cleaning is essential to maintain this precision. If you neglect to clean your rolls on a regular basis, you will not get the most out of your anilox investment. Plugged cells will affect print quality and cause you frustration, waste and downtime. An anilox cleaning program consisting of daily, weekly and deep cleaning will preserve the integrity of the anilox engraving and ensure quality, press efficiency and longer anilox life.

When a newly engraved anilox roll arrives from the manufacturer, volume is even across and around the surface of the roll. As the roll is used, however, a residual amount of ink or coating material is left behind in the cells after the transfer has taken place. The residue dries and creates build-up in the cells.  Over time, these deposits decrease the capacity of the cells and reduce their ability to carry and release the volume of ink or coating for which they were designed. This residue also raises the surface tension, or dyne level, of the roll and increases the tendency of the coating to “cling” to the surface. When this occurs, the roll will not release the proper volume or ink or coating to the plate.

Benefits of regular anilox roll cleaning:

  • The repeated transfer of a precise volume of ink or coating
  • Consistent coverage
  • Reduced labor and less downtime
  • Fewer job rejections and waste
  • Longer anilox life and lower re-working costs

Flexo Concepts recommends a 3-step anilox roll cleaning program:

1. Daily wiping to prevent ink or coating build-up
Applying a liquid cleaning agent by hand and wiping down the roll with a clean, lint-free cloth on a daily basis is the simplest and most effective way to prevent keep ink and coating from drying and building up in the cells. As a basic rule of thumb, the best time to clean a roll is as soon as it is removed from the press. The longer inks, resins, adhesives, etc. have been allowed to sit in the engraving, the harder these materials are to remove. To maximize cleaning performance, choose a cleaner specifically formulated to remove water-based, UV or solvent-based chemistries based on your application.

2. Weekly scrubbing with a paste-like cleaner and an anilox cleaning brush
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Manually scrubbing the roll once or twice a week with a brush and a paste or cream chemical cleaner will mechanically loosen and remove any ink or coating residue that remain in cells despite daily cleaning. The cleaner is applied to the roll, vigorously scrubbed in a circular motion with an anilox cleaning brush and flushed with water while the roll remains in the press. It is important to remember that stainless steel brushes are suitable only for ceramic anilox surfaces and brass bristles should be used for chrome surfaces to prevent damage to the engraving.

3. Monthly deep cleaning to remove tough ink or coating deposits
Over time a residual amount of ink or coating material is left behind in the cells and the roll requires a deep cleaning to remove these tough deposits. The most common methods of deep cleaning are chemical wash and ultrasonic. The roll is removed from the press and placed into a chemical bath where it soaks in a powerful cleaning solution before being subjected to a high pressure rinse or ultrasonic vibrations to loosen and dissolve the deposits. These methods vary in cleaning effectiveness, risk of damage to the roll, and water and chemical consumption.

Like on other parts of the press, a maintenance program for anilox rolls keeps the ink delivery system running at its peak. Regular anilox roll cleaning will prevent anilox cells from plugging with ink and coating residue and stop build-up before it dries. Maintaining anilox rolls through a regular cleaning program can pay off tremendously in terms of maximizing print quality, press efficiency and cost control.

Click here for more information on our anilox cleaning brushes

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Viscosity & pH Control: Increasing Productivity Through Automation

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Paul Lancelle, Technical Solutions Group, All Printing Resources, Inc.

Ongoing control of ink viscosity remains as, arguably, the most significant variable in the flexographic reproduction process. If it is not controlled continuously and closely, uniform ink coverage and accurate color match cannot be achieved. Given the costs of solvent and water-based inks, printing operations of any size can save significant costs by controlling ink viscosity.

A good incentive for increasing your understanding of viscosity is to keep in mind that improper viscosity can cost money: a shift of one second on a #2 Zahn Cup can result in 50% excess ink laydown. Improper or high and low “spikes” in ink viscosity also result in ongoing color management issues, as this same one second shift can result in a change in color measuring dE 2 or greater. Viscosity affects not only the hue and strength of the printed color, but impacts other print quality attributes including ink lay, dot gain and trapping. Additionally, performance properties such as coating weight, drying speed and solvent retention are all affected by ink viscosity.

For water-based ink applications, equally important is the ongoing monitoring of pH, due to the interrelationship that exists between pH and viscosity control. Water based inks rely on precise pH control to maintain resin solubility and stability. While manual monitoring remains the “least expensive” means of monitoring pH and viscosity throughout a print run, it is quite common for these methods to quickly turn into a “tail chasing the dog” scenario due to several difficult to control factors:

  • Inconsistent measurement practices between operators
  • Accuracy of efflux cup
  • Irregular timing between monitor checks
  • Disruptive solvent/amine mix “shock” (too much at once)
  • Pigment differences between inks
  • Varying solvent/amine evaporation points

Whether running water or solvent based ink systems, checking ink manually with a stop watch and measuring cup or automatically with an unreliable mechanical system simply does not meet the demands of today’s packaging buyer in terms of color consistency within a job and from one run to the next.

Of equal significance lies the point of ink temperature control. Temperature is a critical parameter in the printing process, and is very often underestimated. Ink temperature is affected not only by ambient environmental conditions, but by press speed and run length, as well. With the ongoing trend toward higher press speeds, ink temperature control has warranted a greater focus. As ink temperature rises, viscosity drops and evaporation rates increase, resulting in another critical balance point. By controlling the ink temperatures, significant ink and solvent savings can be realized and color stability will improve, as well.

Automated control systems were developed to overcome shortcomings and limitations of manually measuring viscosity and pH. Although automated systems have been available for many years, a better understanding of ink, the printing process and the influence of viscosity and pH on print quality have resulted in improved and more reliable systems. Most new presses sold today, particularly in the wide and mid-web segments, come equipped with varying types of advanced automated viscosity, pH and temperature control systems. It is of common industry agreement that ink viscosity should not vary by more than +/- 5% throughout a run… a standard that is difficult to achieve with manual measurement practices. Most of today’s automated systems feature even tighter tolerances than that. The benefits realized by the printing operation are numerous, but primarily include:

  • Ink and solvent savings-often estimated between 25-60%
  • Print quality and consistency through consistent color reproduction
  • Ink quality is maintained throughout a run
  • Maximized press operating speeds
  • Minimized waste
  • A permanent record for quality control purposes

For these reasons, it is well worth the consideration and investment in retrofitting older model presses with automated control systems. Print managers must select a viscometer/pH control system based on their production needs, and this is dependent upon numerous factors, including operator acceptance, consistent measurement and control, fit with existing equipment, expected cost savings, and maintenance and repair.

FIGURE A “Falling Body” Inline viscometers

FIGURE A
“Falling Body” Inline viscometers

The traditional and prevalently common method of automated viscosity control in the printing industry has been with “falling body” technology. The basic concept is to measure the elapsed time required for a ball to fall, under gravity, through a sample-filled tube. The measurement is taken periodically and is not a continuous measurement. See Figure A.

More recently, the flexo print industry has been moving more towards the adoption of “vibrating rod” technology, which consists of a straight metal rod maintained in resonant vibration by a continuously applied power source. Installed in-line to the fluid flow, the sensor is between the ink pump and printing deck. Using the integrated computer, the viscometer emits sound waves in the ink-much like a musical “tuning fork. “A detection circuit then analyzes the changes in these waves caused by the tiniest of

FIGURE B VISCOWAVE Vibrating Rod in-line viscometer

FIGURE B
VISCOWAVE Vibrating Rod in-line viscometer

variations in the ink viscosity. See Figure B.

The advantages demonstrated with “vibrating rod” technology, particularly when choosing the VISCOWAVE technology offered by New Celio Engineering, are multiple when compared to “falling body” methods. Demonstrated improvements can be seen from:

  • High accuracy rate
  • No moving parts=cleaning not required
  • Easy in-line installation
  • No maintenance
  • No wearing parts
  • Compact and lightweight
  • Full stainless steel construction

In addition, the VISCOWAVE comes with built-in temperature measurement and has options for controlling ink temperature to provide a “complete package” toward automated ink control.

Consideration of the added benefits recognized from the higher accuracy and dependability combined with reduced maintenance and cleaning may lead to printers with previously installed versions of automated viscosity control systems recognizing a significant ROI when upgrading to these newer technologies. The same concept holds true for automated pH control, as earlier systems were often found to be challenging to clean and maintain.

APR represents New Celio Engineering, offering a full line of viscosity, pH and temperature control systems, as well as heat exchangers, wash up systems, mixing stations, solvent and/or ink distribution lines. Customized turnkey solutions can also be provided. To learn mopre about the New Celio System, click here, or contact one of our Technical Specialists.

For more information, call us at 1-800-445-4017, or fill out the Information Request Form.

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Filed under Ink, Printing, Viscosity

Polyester Containment Blades Win over Steel

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Polyester_coil_knockout_300x135For such a seemingly insignificant part of the press, the containment blade’s job is an important one.  After all, it is a fundamental component of the doctor blade chamber.  By forming an enclosed system, the containment blade plays a key role in allowing the printer to maintain ink viscosity, minimize skimming, lower ink consumption and simplify cleanup.

In wide web applications, choosing polyester containment blades over steel is a smart way to save money, improve safety and reduce your environmental impact.  Unlike the metering blade, which has a direct impact on print quality, the containment blade only has to contain ink in the chamber.  This gives a printer more options to choose from with regard to blade materials.  Learn why polyester is a superior choice over steel.

Top 5 reasons to switch to polyester containment blades:

  1. Trail doctoring – Some printers experience trail doctoring at higher press speeds when using steel containment blades. Steel blades are too stiff to allow back-doctored ink to pass underneath the blade and back into the chamber.  Ink builds up on the back side of the blade, pools at the end of the chamber and eventually slings onto the press and web.  This situation not only creates a mess but also affects print quality.  Printers can eliminate trail doctoring by using polyester containment blades.  This material is equally effective at containing ink in the chamber but thin and flexible enough to let back-doctored ink return to the chamber.
  2. Cost – Polyester containment blades cost substantially less than steel blades. The price per inch for polyester typically ranges from one-third to one-half that of steel.
  3. Safety – By replacing one of the steel doctor blades in a chamber with polyester, you can reduce your risk of doctor blade injuries by 50%. Unlike steel, polyester blades are safer to handle than steel and won’t cut press operators when they are installing and removing them from the press.
  4. Environmental impact – During production, polyester blades emit a small percentage of carbon dioxide compared to steel blades. Using polyester containment blades can help printers meet requirements for reducing their carbon footprint.
  5. Anilox damage – Polyester containment blades will not score or damage anilox rolls. The material is soft and contains no sharp fragments which can break off, become lodged against the roll and destroy the engraving as the roll turns.  The material is non-abrasive and won’t cause excessive wear on the roll.  Replacing or re-engraving anilox rolls is expensive, so extending their life can be a huge cost savings.

Printers are always looking for ways to improve efficiency and save money.  Why not choose a containment blade that not only costs less but also has additional pressroom benefits?  Polyester containment blades offer a less expensive and safer alternative to steel that also reduces trail doctoring and environmental impact.  It’s amazing how such a small change can make such a big difference!

Request a Polyester containment blade sample

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6 Ways to Get Your Branded Materials to Market Faster

sgk_logo_pmsBy Jesse Moen, Director, Continuous Improvement Practice, SGK

Getting packaging, promotional, digital, and other branded materials to market quickly can feel overwhelming.

As organizations grow, additional layers of approvers and stakeholders become involved in the supply chain, accountability becomes decentralized and ambiguous, and workflows do not evolve quickly enough to accommodate the larger scale of work required.

What should be a relatively straightforward process becomes bogged down in a complex and time-consuming web of competing agendas, obsolete policies, and siloed communications. For example, some Fortune 100 clients require a four-month lead-time for FSIs and a six-month (or more!) lead-time to redesign a package. While these may be outliers, they are representative of the types of problems many organizations face, and they prove that agility and responsiveness are critical to achieving topline growth.

To become more nimble, marketing organizations need to think “lean” and remove non-value-adding tasks from their branded material supply chains.

Here are six proven practices:

1. Validate your inputs. While this may be considered a no-brainer, most organizations struggle with input validation because it’s actually pretty hard. Design managers, production managers, and agency PMs are under enormous pressure from Brand and Sales to “just go.” Projects are kicked off without briefs, die lines, approved claims, or formulas. While this “fix-it-later” mentality may work anecdotally at the enterprise level, it drives multiple rounds of time-consuming revisions into both the creative and production processes. This habit is the primary root cause of design and production revisions. Strong discipline and leadership are required to break it.

Once this practice has been abandoned, it’s time to organize. Sit down with your agency/production partners to logically categorize all the inputs required to create/produce your materials. Choose a taxonomy that makes sense for your organization. Then organize the information into a standardized form. This can be as simple as a spreadsheet or as advanced as a database. If you go the database route, you can begin experimenting with linking the data directly to artwork.

The difference between organizations who do this well and those who struggle is striking. Organizations who have stringent validation procedures in their packaging workflows see upwards of 85 percent of all packaging changes approved within two cycles or fewer.

Organizations with poor validation procedures perform much worse, with only 60 percent of changes approved in two cycles or fewer. This 25-percentage-point difference can translate into thousands of hours of lost workforce capacity, weeks added to each project, and significant change fees from agencies and production partners.

2. Streamline your routing and approval process. Assuming you have a formal routing and approval process, dig in and question why so many people need to approve your packaging and promotional materials. The more people involved in approving work, the greater the drain on your organization and your marketplace agility.

Approvals are a hot-button issue within any content-rich organization. There are often competing internal agendas demanding involvement in approvals, but there is often just as much support for improving this process. To do so, look for opportunities to take people out of the approval cycle, to establish parallel path approvers, and to create simplified processes for simple deliverables.

Streamlining this process can make a significant impact on cycle times. For one CPG, the number of approvers required across all packaging and promotions routing and approval workflows was reduced by 67 percent. This equated to 4,000 hours of annual labor savings and reduced average routing cycle times by over a week.

3. Eliminate redundancies. Analyze the duties and tasks performed by your marketers, marketing communications staff, and agency/production partners. Look for redundancies in project management, approval processes, and meeting attendance. You’re apt to discover that many of the redundancies will be tactical tasks; while each task may only take a few minutes, adding them up annually over thousands of packaging changes, promotional materials, etc. amounts to a significant loss of time and energy.

For example, an analysis of the duties and tasks performed by junior marketers and marketing communications staff at one CPG revealed task redundancies in the initiation and management of packaging projects. Post implementation surveys revealed a 15 percent capacity increase within the junior marketer role once these redundancies were addressed. 

4. Focus resources and time on what’s most important. Evaluate your mix of marketing materials and decide which consumer touchpoints are critical to your growth. Then critically evaluate all workflows that support the less critical touchpoints. Media that are not delivering should require little to no attention from marketing leadership in a$1B+ organization. Relentlessly pursuing this philosophy will free up staff to execute more efficiently on high-value activities.

A major CPG did just this and removed all tasks related to design initiation, review, and approval processes for FSIs from their Marketing team. Across all divisions, this freed up a collective day and a half of weekly status, review, and kickoff meetings.

5. Go digital. Requesting and trafficking files on CDs and printouts is the antithesis of a “lean” process. They need to be shipped, stored, and managed, and they can’t be indexed for searching on your computer. An all-digital workflow empowers your organization, driving speed, efficiency, and accuracy throughout the enterprise—a velocity that can provide a competitive difference.

For example, a client had been requesting disks and three sets of printouts for all of their final artwork files. These assets were then stored and scattered across expensive office space in midtown Manhattan. After working through the perceived needs of the organization, we helped establish a workflow and file management strategy to completely eliminate all of the disks and printouts. Doing so saved the organization thousands of dollars in shipping/courier fees, cleared up valuable office space, and mitigated the need to organize and store thousands of files annually.

6. Remove communication roadblocks. It’s a common occurrence: agency and production partners are often frustrated by the excessive communication pass-throughs by clients and the red tape around information required to create their branded materials. But trusting your partners and enabling them to communicate deeper into your organization provides them with a roadmap for information. Empower them to initiate approval routes inside your online approval tool. If you have serious reservations about this, spend a few minutes evaluating your concerns to understand if they are related to control, partner ability, or something else. The idea is to remove obstacles and simplify for speed.

To that end, the solution could be as simple as assigning multiple points of contact based on areas of expertise within your organization. One consumer promotions agency was required by a CPG to leverage a single point of contact within the CPG’s brand design group to field all questions and requests. While this strategy was intended to ensure brand consistency across marketing media, it was inadvertently tripling the number of queues within the workflow for tactical requests. Eventually, the agency was provided key contacts within the CPG organization for tactical requests, such as die lines, bar codes, legal copy, and offer codes. This simple empowerment eliminated two workflow queues as well as the redundant communication management performed by the brand design manager and agency project manager.

The speed at which branded materials are created and deployed can drive increased sales, enable organizations to respond to quick-turn opportunities with key retail partners, and free up resources to put against growth objectives. The increased productivity that optimization offers can drive your brand’s performance by delivering it to market more quickly, more efficiently, and more cost effectively. The successful implementation of the strategies outlined above will help your organization cut non-value-added time and energy from your branded material supply chains and streamline your processes.

About the Author: 

Jesse_Moen_2013

Jesse Moen brings 10+ years of expertise in brand development/deployment and in the practice of continuous improvement. He is the driving force behind the success of the SGK Continuous Improvement Practice (CIP) and has strategically led initiatives with CPGs and retailers such as Campbell’s, Dial, Diamond Foods, General Mills, Logitech, Merck, Proctor & Gamble, 3M, Safeway, and Titleist. Jesse earned a MA from the University of California, Berkeley and holds a Lean/Six Sigma Black Belt from the University of St. Thomas.

http://www.sgkinc.com | Jesse.Moen@sgkinc.com

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Are you experiencing Pin-holing and Production Pitfalls? – Part 2

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In the previous Part I of this blog http://www.flexoglobal.com/blog/, I talked about the ink transfer process in flexographic printing and how it can introduce the problem knows as pin-holing. Over the years, manufacturers have tried to solve the problem in various ways with limited success. Likewise, flexo printers have tried to compensate for the pin-holes by applying more ink to the job, and more pressure on press, but that only drives up costs and introduces other complications.

The best way to solve the problem is to use a specific imager technology to apply a texture pattern on the surface of the plate that breaks up the surface patterns from the anilox roll. By breaking up the anilox pattern, it breaks up the pin-hole pattern, and significantly improves the ink transfer. As I noted in my last installment, that solution exists today and has been driving improved quality in flexo around the world.

Kodak’s innovative, award-winning KODAK DIGICAP NX Patterning is a standard component of the KODAK FLEXCEL NX System designed to address these ink challenges in flexo—specifically solid ink densities compared to gravure printing. Enabled by KODAK SQUARESPOT Imaging Technology, unique to the FLEXCEL NX System, the function of DIGICAP NX Patterning is to image a unique pattern into the surface of the plate.

Compared to traditional surface patterning technologies, DIGICAP NX Patterning is significantly smaller and finer. It is a true micro surface texturization of the plate surface, applied to the 1-bit TIFF in the RIPing process, and utilizing half-pixel imaging at 10.6 x 5.3 microns size, or 2400 x 4800 dpi.

With the ability to create unique patterns in the surface of the plate that overcome production challenges with heavy solid areas, or the application of white ink for flexible packaging, users are seeing dramatic quality improvements. Because of the improved ink transfer, printers are able to more easily achieve their target densities and eliminate the need to chase density with more ink, more pigment, and more pressure. For flexo printers, the result is greater color gamuts, cleaner brighter colors, better print quality, higher print speeds, and greater consistency.

Why are color gamuts improved with this solution? Because the solids are clean rather than being pin-holed, which results in light and dark variation in the colors, often the cause of the term “muddy” colors associated with Flexo. Also, when overprinting to build colors such as in 4- or 7-color process, the results are cleaner and brighter. Having the ability to build cleaner and brighter colors enables flexo printers to do more of their work with process printing instead of having to rely on more expensive spot colors. It also improves the printer’s ability to standardize ink sets, whether for 4- or 7-color process printing.

DIGICAP NX Patterning has been one of the lead technologies in the “flexo revolution” over the last five years, truly allowing printers to achieve the densities of gravure printing, and helping to stop the chase for density caused by excessive pin-holing with traditional flexo. It has been a key enabler in brand owners increasingly accepting that flexo is no longer a second-class print process, easing the transition from offset and rotogravure to flexo.

Innovation in flexo is an ongoing process, and one in which Kodak maintains a passionate commitment. R&D teams continue to explore additional areas where differentiated plate imaging technology can further increase print quality and reduce or eliminate production obstacles. As we look to the future, Kodak technologies such as DIGICAP NX Patterning, SQUARESPOT Imaging Technology, and KODAK HYPERFLEX Imaging Software will provide the foundation for technical advancements in flexo.
Printers are certainly benefiting from these innovative imaging technologies, but they are not the only ones. Brand owners are constantly looking for ways to design packages that catch the eye of the consumer and set their products apart from the competition. Print quality, color vibrancy, and reproduction accuracy are top of mind for marketers—it’s the job of the printer to make it happen and to keep costs in line.

Dr. John’s Contact Information:

John-Anderson-AugFor anyone who does want to email me, please use john.anderson3@kodak.com and please don’t miss out the number 3 in the address, or you will reach another John Anderson in Kodak manufacturing!

Have a wonderful day,
Dr. John

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What measurement condition is your spectro wearing?

by John Seymour, John the Math Guy

These days, all the fashionable spectrophotometers are sporting the new measurement condition, M1. It’s all the rage from Alabama to Aukland. If your spectro hasn’t adopted this new look, then, sorry. It just won’t get invited to the parties with all the cool spectros.

But what is this hip new fashion trend, and why should you care? This blog post goes undercover to get the inside story about the new measurement conditions in ISO 13655. This reporter investigates the four measurement conditions (M1 through M3), but more importantly, explains why you would choose one over the other.

Summary of the measurement conditions
Way back in 2009, when all of our spectros were wearing styles appropriate to that long-lost era, the ISO Technical Committee 130 came out with a new fashion edict. Spectral measurements henceforth shall be made according to one of four types of illumination, and the one chosen shall be reported along with the data.
(Note that the word “shall” is standards-speak for “you gotta do this if you want to comply with the standard. The other key word is “should”, which means “as experts, we recommend doing this, but it is not a requirement for compliance”.)
Why all the fuss? The big driving force behind this is the proliferation of Fluorescent Whitening Agents (FWAs) in paper. These are substances (stilbenes, for the chemists and lingo-philes in the crowd) that absorb ultraviolet light and re-emit that energy as blue light. This makes paper look whiter – which is what everyone wants and craves.I should make a note here. The popular media (Fox News and MSNBC) call them “OBAs”, meaning “Optical Whitening Agents”. While this moniker is correct – stilbene does make paper brighter in an optical kind of way – I would say that so does TiO2 and bleach. The term “OBA” fails to emphasize the key operative, which is fluorescent light.I have already written a bit about the basic problem and the reponse to it. The following exciting articles focus on the “M1″ stuff.
Layman’s Guide to ISO Print Standards
Here are the four exciting choices for measurement conditions:

Most handheld spectros use an incandescent bulb to illuminate the sample. Remember those kinda lights? A little piece of wire called a “filament”? Some electricity going through it? And then the wire gets hot and glows. Guess what? This light source doesn’t have all that much UV content. And guess what again? The amount of UV varies a lot from one instrument to the next.

M0 is based on a hypothetical incandescent light source. For an M0 measurement, the light hitting the sample should(note the word) conform to CIE standard illuminant A – which is to say, a light bulb. The word “should” is important and intentional. This little tiny loophole allows anyone to use the older spectros and remain compliant. This would be a totally dumb idea, but you could use a lightning bug with a hangover as the light source for your M0 illuminant and still be compliant. No one’s gonna check. M0 is the nightclub that any spectro can enter.

If you want to find out if your local neighborhood color scientist is hip, just ask whether he or she is raving about M1. All the hip ones will say M1. The illumination for this measurement condition is based on a theoretical daylight called D50. This puppy packs a pretty good wallop of UV content, so this will excite those ol’ OBAs, if you know what I mean.

Does your spectro want to strut its stuff at the M1 Bistro? The security guard is checking IDs at the door, and any spectro failing to provide the proper levels of OBA ain’t gonna be ordering an avocado-tini at this joint.

OBAs love attention. The only reason they show up at parties is to be seen. But when the spectrophotometer breaks out it’s M2 light source, the OBAs become as invisible as that woman who married Jimmy Fallon. An M2 light source will be almost kinda completely devoid of UV light.

How do you get into this club?  If your spectro comes knocking at the door, there will be a test, and I’m, not talking “written exam”. The test is described in Annex H. To perform the test, you need to get pretty intimate with the instrument. It would make a TSA agent blush.BTW, the TAGA 2015 conference in Albuquerque (March 22-25, 2015) will feature a micro-conference on OBAs. We had a whole bunch of papers on the subject, so the VP of papers decided to talk it up big. Here I am, talking it up big.M2 might seriously have been considered a contender for preferred condition. It does level the playing field when it comes to UV excitation. All M2 instruments have no UV, so none of them should cause OBAs to glow. And they should all agree.But, to make this whole opera work, the light booths really should have the same amount of UV content. And if there were no UV content in the viewing booth, then papers with OBAs would look dingy. And no one wants that.

You may think that M2 is an exclusive club, but M3 is even more exclusive. First you need to get into the M2 club even to be able to bribe the bouncer to get into M3. And you gotta be wearing sunglasses. Not just any sunglasses, but sunglasses with polarizing filters. As a result, specular highlights and fluorescence are not allowed in M3 disco.

So… if you happen to be thinking about dating a spectro, how do you decide which one is right for you?

Do I smell OBAs?

Do you have OBAs?
I know this probably sounds personal, but the first concern is whether you have OBAs in the house. If you don’t have OBAs, then (theoretically), there should be no difference between M0, M1, and M2 measurements. You could use your older instrument that doesn’t offer a choice, or you could go with one of the newer instruments that offer M1.

That question “do you have OBAs?” is pretty much the same as “are you measuring paper?” The thing is, paper is normally brown – the color of a grocery bag. Special processing must be done to make paper white. That could involve bleaching, or it could involve OBAs. Today, almost all paper uses at least some of the latter.

So if you happen to be measuring ink on paper, then you just gotta plunk your money down for an M1 instrument, because you will find your old M0 instrument disagreeable. It will disagree with your light booth, with M1 instruments, and even with M0 instruments from other families. The thing is that pretty much all paper for commercial printing will have OBAs added, so you have a choice as to whether to deal with a petulant teenager, so buy into the M1 craze.

I should add that switching over to the M1 instrument is only part of the change that you are facing. When you make the change, you will find that you need to make sure that your lighting booth adheres to the 2009 version of ISO 3664, so it has the same amount of UV content as the spectro. And all the data that you had previously measured, like profiles of your press and target colors, will need to be updated. I know, not a simple solution.

That covers web offset, sheetfed, and newspaper printing. The situation in packaging is a bit more complicated, so let me describe some cases. Let’s say that you are measuring color on foils or poly. I might be wrong here, but I don’t think you will run into any OBAs. Foils and poly and the floodcoat use something like TiO2 to add whiteness and opacity. Floodcoats wouldn’t benefit by OBAs, since they are not brown. So, like I said, I could be wrong, but I think it would be silly potatoes to add OBAs to foils.

If you are measuring kraft paper, then I think you are likely free and clear as well. If the paper is brown, then clearly no one cared enough to take the time to add OBAs to make it white. Then again, if the kraft paper includes a certain amount of recycled paper, then the OBAs might be sneaking in through the back door.

UV LED “blacklight” flashlight from Amazon for $12.89

How about printing on white cardboard or card stock? Now things get uncertain. You gotta ask yourself, how did the cardboard get white?  Sometimes, cardboard is made white by applying a floodcoat of white stuff. This white stuff might be something like titanium dioxide, which is naturally white. So, it is unlikely to contain OBAs. Then again, cardboard may be white because it has been laminated with paper. If that paper is white, then you can guess that it has OBAs. Another possibility is that the white card stock might be white because the paper is white. So, it could have OBAs.When in doubt… I would recommend having a UV light source around. Anyone who survived the sixties is familiar with these. Today you can get UV flashlights made from LEDs. Cheap and convenient, and a good way to test for the presence of OBAs.

Do you want CIELAB values?
The second concern is whether you want CIELAB values. In my not-always-humble opinion, computing CIELAB values from a polarized instrument (that is, M3) is just plain silly. The whole point of CIELAB is to emulate how our eyes see color. Unless your product is destined to be viewed by people wearing polarized sunglasses under light that is polarized the other way, then CIELAB is probably the wrong choice.

ISO 13655:2009 agrees with me on this one. Here is a quote from Annex G:

Notwithstanding the beneficial effects of crossed polarizers [M3] in the special cases mentioned above it needs to be noted that for most other instances in colorimetry the use of polarizers is counterproductive.

So, if you want to compute CIELAB values, then you must use M0, M1, or M2.

Are you doing process control on a cold set press?
M3 does not mix with CIELAB, but it does mix with density. ISO 13655 has this to say about where the M3 condition might be applicable:

It was discovered that the installation of crossed polarizing filters serves to extend the linear part of the density versus ink film thickness dependence towards higher values, and serves to greatly reduce density dry-back.

There are two points here. The first is that M3 “extends the linear relationship between density and ink film thickness.” This is believed by many, but it is unfortunately incorrect. In my blog post on polarized densitometers I presented a plot showing that there is a linear relationship between polarized and unpolarized density. If polarized density is linear with ink film thickness, then unpolarized must be as well.

The second point from the ISO 13655 quote is that M3 reduces dry-back. Measurements made directly after printing on a cold set press will not change as the ink dries. This is true, and that was really the whole point of the blog post on polarized densitometers. So… I won’t belabor the point here. But I will encourage you to go read the post.

And I will also reiterate a point that I have iterated a couple three times in previous blog posts. There is a difference between “process control” and “satisfying-your-customer control”. The first is about making sure your process is appropriate and repeatable. The second is about making sure that the payments from your customer are appropriate and repeatable. Density and M3 are process control parameters. CIELAB is a product expectation control parameter.

So, M3 can be useful when you are measuring ink that is not quite dry, but its use should be limited to within a given plant. No interchanging of data, you hear?

Are you doing process control on materials with OBAs?
Just in case you have been just too enthralled with this page-turner of a blog post to have been keeping track…

M0 is ok if you have a legacy instrument, and you aren’t really that into OBAs.
M1 is preferred, especially if you might think you have a little issue with OBAs.
M3 is acceptable, but only for process control – no CIELAB allowed.

What about M2?
OBAs are tricky little devils. They make the paper look whiter. But when you apply ink to them, a funny thing happens. The ink blocks the UV, so that the paper under the ink does not get artificially brightened. This can make things a little weird if you are a process control freak. Especially when you come upon an ink that doesn’t happen to block the OBAs. The relationship between the density of the paper and the density of the solid ink gets befuddled.

That last paragraph was written yesterday. This morning, I looked at some data that I got from my good buddy, Gerry Gerlach. His data refutes the stupid statement that I made “The ink blocks the UV.” Good God! What was I thinking. In his data, cyan, magenta, and black all do a pretty good job of blocking the UV. But for yellow ink (and aqueous coating on bare paper) there is a large difference in b* between the M1 and M2 measurements. In other words, the ink and coating are letting the UV light through, i.e. are transparent in the UV. I suspect that not all yellow inks do that, and certainly clear coatings may differ.

So, M2 is a process control thing, maybe better than M1. If you are trying to establish that you are putting a consistent amount of pigment on the paper from day to day, this might be a good thing to try. But as with M3, I caution that this is not the same as making the correct color.

M2 has found another purpose in life just recently with the invention of the OBA index of a paper. It has been noted that OBAs will tend to decrease the b* of a paper. A substrate might measure a little yellowish under M2, maybe b* is +2. If you measure that same substrate under M1, the b* might go negative, maybe -3. The OBA is the difference between the M2 and M1 measurements. In this example, the OBA index would be 5.

Are you sufficiently confused?
I hope this has blog post on illumination conditions been enlightening, no pun intended. Actually, the pun was intended. But the enlightenment was also intended.

John Seymour

About the Author
John Seymour holds the title principal engineer for QuadTech, where he has been doing research in printing, color theory, and imaging since 1992. John was instrumental in the development of QuadTech’s Color Control System and AccuCam. John currently holds seventeen patents and has authored thirty technical papers. He is an expert on the Committee for Graphic Arts Technologies Standards and ISO TC 130, and currently serves on the board of the Technical Association of the Graphic Arts. He writes a blog under the pen name “John the Math Guy”, which is described as “applied math and color science with a liberal sprinkling of goofy humor.”

Prior to working with QuadTech, John worked as a scientific programmer in medical imaging, satellite imagery, electron microscopy, and spectroscopy. He holds bachelor’s degrees in mathematics and in computer science from the University of Wisconsin-Madison.

John had a hobby job as a karaoke host, going under the name “John the Revelator”, and before that his hobby job was teaching remedial math at a local university. He likes to think that he is gifted at “edutainment.” John teaches a color science class for QuadTech and has traveled as far as South Africa, England, Germany, and Hong Kong on speaking engagements.

Visit John’s Blog, John, the Math Guy – Applied math and color science with a liberal sprinkling of goofy humor, at http://johnthemathguy.blogspot.com/

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A Guide to Reflectance Measurement Devices, Part 3

by John Seymour, John the Math Guy

I continue my action-packed series on the plethora of devices for measuring reflectance. Today’s topic is the spherical instrument. This blog post promises to be exciting because I know virtually nothing about the topic. This of course is generally the case when I write a blog, but in this case, I might actually admit to being ignorant if you get enough beer in me. Please try.In the first part of this series, I made the comment that your choice of instrument may not be directly related to which type works the best, but may be dictated by which industry you are in. If you are in the print industry, you are likely to be using (or required to be using) a 0/45 instrument. But, if you are measuring textiles or paint…

Are you measuring either cloth or paint?
If, by chance, you told the reflectance measurement device salesperson that you were in textiles or paint (personally, I am in lady’s underwear), then she would most likely point you to the integrating sphere section of the store. There you would see a few shelves of instruments that are labelled either 8/d or d/8. These are in the “spherical instruments” department.
 When paint and textiles collide
When paint and textiles collide

 

An instrument that is 8/d will have illumination that hits the sample at 8 degrees, which is to say, just off the axis perpendicular to the sample. Light will be collected democratically — without regard to race, creed, or direction of travel when leaving the sample. This certainly has a satisfying feel to it. It should appeal to the physicist in all of us to know that we are collecting pretty much all of the reflected light. So that’s good.

 

The picture below shows how this is accomplished. Light enters through a port near the top of the sphere. When light reflects from the sample in all directions it hits the inside of the sphere. The inside of the sphere is coated with stuff that is highly reflective and very matte, so the light bounces off in all directions. And then this light hits the inside of the sphere again, and bounces yet again. Eventually, some of the light hits the detector and is measured. That sphere, by the way, is called an integrating sphere.

 

Hunter's spherical
Illustration of an 8/d spherical instrument or a Christmas tree ornament
(from “The Measurement of Appearance” by Richard S. Hunter, John Wiley, 1975)

 

While it feels good to collect all the light, on the other hand, this is clearly not a measurement geometry that simulates anything in the real world. Light comes in at one angle – that part is reasonable enough – and is measured (seen) at all angles. What? Who has eyes like that??!?!

 

On the third hand, remember what my high school buddy, Herrmann von Helmholtz said: you can switch the illumination and viewing and see the same thing? So, 8/d will give you the same numbers as d/8. And a d/8 measurement is more or less what you get when you look at a car on a cloudy day… illuminated from all directions (well, mostly), and viewed at close to straight on (well, sometimes). The pictures above and below are from one company that bragged about both d/8 and 8/d designs while I was in high school.
US 4,093,991
A d/8 instrument or an engineer’s version of an ornament
(from US Patent 4,093,991, assigned to Hunter Labs, 1977)

 

SPINing and SPEXing
When using a d/8 or an 8/d instrument, you have yet another decision to make: SPIN and SPEX? These stand for SPecular INcluded and SPecular EXcluded. As with a polarized versus non-polarized spectrophotometer, this is an attempt to differentiate between the bulk reflection and the specular.

The SPIN instrument is just what I described previously. The light is captured from all directions without regard to race, creed, or sign of the zodiac. A SPEX instrument is almost the same, except that a black plug is put at the specular angle (at 8 degrees opposite the illumination). This keeps the detector from ever seeing this specular light. Clever, eh?

Depending on what you are doing with the measurements, one or the other might be more better. Consult your bartender or cosmetician for further advice.

Why is a spherical instrument good for cloth?
There is an inherent problem when you try to measure textured cloth with a 45/0 instrument. The texture will block 45 degree light from getting very far inside the warps and woofs of the cloth. The detector will miss out on seeing that rich color deep down in the fabric. Under typical conditions, our eye will see that light reflected from deep inside, since we normally have light that is hitting the fabric at angles other than 45 degrees. I might add that the fabric I most enjoy viewing is not presented as a flat piece. I much prefer fabric that has some curves to it.So, a spherical instrument has a big advantage when it comes to cloth, or carpet, or textured paint.
 Measuring a lion's tongue
This man is measuring the rough surface of a lion’s tongue with a 0/45 spectro.
I don’t recommend this.

 

Why is a spherical instrument good for paint?
You want your paint formulation software to work? Don’t even think about using a 0/45 spectrophotometer! A 0/45 spectro is very sensitive to the roughness of the surface that you are painting. If you mix the pigments of the paint based on measurements of one surface and then paint a surface that has a different roughness, guess what? The 0/45 spectro will see a different color. A spherical instrument is more forgiving.

That’s the good part. You can paint one surface to get your paint recipe and the use that paint on another surface and measure the same color with your spherical instrument.

But the bad part is that a spherical instrument is more forgiving – probably more forgiving than the flibbertigibbet who may or may not pay you because the house paint is the wrong color. Generally speaking, measurements made with a 0/45 spectrophotometer correlate better with what we see. Note that I have italicized those words for the benefit of those people who will disagree with me.

This is a point that I find myself making over and over again… process control versus customer needs. Frankly, I am getting sick of talking about it. Some day, I’ll just dedicate a whole blog post to the subject and stop ranting to my therapist.

What if you live at the intersection of textile and print?
 There are some poor sods who find themselves needing to make printed stuff look like textured textiles. Which type of spectro should they use?!?!?
The choice
Textiles or graphic arts?

 

Some of these poor sods are printers of catalogs. The color of the dress is critical, so they measure the lady’s dress. What do they measure it with? A spherical instrument, of course. Then they go print it and wind up measuring the printed catalog with a 0/45 spectro.

There are also some poor sods who get stuck having to print proofs of textile designs. Once again, we have the graphic arts world crashing into the textile world.

What to do about this? It’s tough, but if the fabric has a mostly kinda sorta matte finish, then the two instruments (d/8 SPEX and 0/45) will read similarly. Just be careful when trying to critically compare numbers from one type of instrument to another.

Are you decorating cans?
 For those who are not in the know, “decorating” is the official way to describe putting ink on soda and beer cans. I know, it sounds kinda froo-froo, but I didn’t make up the term. Most of what I say in these blogs is made up, but this particular factoid is true.
If you are in the can decorating business, and are looking to buy a spectro, then you have to ask the follow-up question: Coke or Pepsi? One of these companies requires that cans be measured with 0/45, and the other with spherical. If I can be trusted to explain their reasoning, one company realizes that 0/45 correlates better with what we see. The other company realizes that 0/45 measurements are hard to duplicate, since positioning is critical.
Coke or Pepsi
One of these is measured 0/45, and the other d/8

About the Author

John Seymour

John Seymour holds the title principal engineer for QuadTech, where he has been doing research in printing, color theory, and imaging since 1992. John was instrumental in the development of QuadTech’s Color Control System and AccuCam. John currently holds seventeen patents and has authored thirty technical papers. He is an expert on the Committee for Graphic Arts Technologies Standards and ISO TC 130, and currently serves on the board of the Technical Association of the Graphic Arts. He writes a blog under the pen name “John the Math Guy”, which is described as “applied math and color science with a liberal sprinkling of goofy humor.”

Prior to working with QuadTech, John worked as a scientific programmer in medical imaging, satellite imagery, electron microscopy, and spectroscopy. He holds bachelor’s degrees in mathematics and in computer science from the University of Wisconsin-Madison.

John had a hobby job as a karaoke host, going under the name “John the Revelator”, and before that his hobby job was teaching remedial math at a local university. He likes to think that he is gifted at “edutainment.” John teaches a color science class for QuadTech and has traveled as far as South Africa, England, Germany, and Hong Kong on speaking engagements.

Visit John’s Blog, John, the Math Guy – Applied math and color science with a liberal sprinkling of goofy humor, at http://johnthemathguy.blogspot.com/

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Building a Superior Artwork Process to Strengthen Your Brand

sgk_logo_pmsBy Jesse Moen, Director, Continuous Improvement Practice, SGK

It’s extremely rare to meet a packaged-goods brand marketer who doesn’t admit, “I have too many rounds of revisions and it takes too long to get my packaging approved.” This is very harmful to brand performance: it reduces speed-to- market and sales and increases expenses across the board. And with new EU and impending U.S. regulations on labeling accuracy, this kind of inefficiency will be even more costly because it leads to mistakes.

Some companies accept packaging headaches. But some dig in and solve them. They start by looking at root causes. There are two, and they are as cultural as they are technical.

The first one goes like this: “I have a new package coming (maybe a full redesign or just an ingredient change). And we have a deadline. I don’t have all of the data I need (something as critical as a nutrition statement or something discretionary, such as romance copy), but there’s so much pressure that we might as well just get started. Just go!”

It’s a fallacy that this pays off in the long run. It works every once in a while, but when a major brand is executing, say, 5,000 packaging changes a year, it’s not sustainable. Pretty soon you’re driving more rounds of revisions, and people are desperately seeking information that should have been there when production began. This costs money, and it’s how costly mistakes happen on shelf.

There’s a practical solution to this, but the change has to be cultural too. The company has to say; “We’re not going to do this anymore. We’re going to figure out what data we need at each stage-gate, and we’re not going to move forward until we get that data.” This is crucial. But it’s hard.

The second cultural issue is package data and how it’s handled; whether a brand manages its packaging in-house or uses vendors. The most efficient brands understand that package data is diverse and it’s coming from everywhere: nutrition facts, ingredients, net weight, barcode, logos and other art elements, romance copy, etc., can come from marketing, design, legal, packaging R&D, product R&D and more. Efficient brands standardize the way this data is gathered and stored. Whether they use carefully curated and protected spreadsheets or a more sophisticated digital database, every stakeholder contributes to a standardized, secure data platform.

As logical as this sounds, there are manufacturers and brands that have a different system for every division. It’s confusing and inefficient, and it makes automation impossible for packaging as well as for related items such as coupons, circular artwork and direct mail.

And it contributes directly to our first root cause – of saying, “Just go!” before all the inputs are gathered, organized and approved. Along with a logical, curated database, efficient brands establish that once the data is stored, it’s “gone” – it’s official and not to be changed. But the data as a whole can’t “just go” until they are all there.

Once a company has addressed these two root causes, then it can standardize according to Six Sigma principles. It can optimize according to lean manufacturing principles. And it can automate by tying the optimized database directly to package design functions.

Current and impending packaging regulations make these improvements crucial. There’s less chance of error at each discrete stage, but there’s a holistic benefit too. If a major brand makes packaging changes to half its SKUs a year, that could total 5,000. EU and pending U.S. packaging regulations will involve every SKU – so let’s say 10,000 for a large brand. If the typical approval process involves 10 people, several rounds of changes and 10 minutes per approval, you’re talking thousands and thousands of hours spent (in a relatively short time) on something that’s not adding to your bottom line.

But what if the proposed U.S. regulations are significantly watered down in the coming year? Brands are free to hope for this, but their issues will remain. Yes, implementing data collection and management best practices is hard work. It might require new technology. And it will require cultural change, which is the hardest. But it’s hard work that pays off permanently. On the other hand, when 10 stakeholders are involved in a package process that starts too early, has too many revisions and still results in an error, that’s hard work with no payoff.

About the Author: 

Jesse_Moen_2013

Jesse Moen brings 10+ years of expertise in brand development/deployment and in the practice of continuous improvement. He is the driving force behind the success of the SGK Continuous Improvement Practice (CIP) and has strategically led initiatives with CPGs and retailers such as Campbell’s, Dial, Diamond Foods, General Mills, Logitech, Merck, Proctor & Gamble, 3M, Safeway, and Titleist. Jesse earned a MA from the University of California, Berkeley and holds a Lean/Six Sigma Black Belt from the University of St. Thomas.

http://www.sgkinc.com | Jesse.Moen@sgkinc.com

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The Evolution of Corrugated Doctor Blades

FlexoConcepts-logo

 

TruPoint_Boxes_250x250Since the 1960s, corrugated printing requirements have grown from simple logistics to eye-catching promotional packaging with skus and tracking information. Improvements in doctor blade materials and tip configurations have played a key role in making this possible. While anilox rolls have gotten better at efficiently transporting a precise volume of ink to the plate, they are only as good as the metering blades they’re paired with: if a doctor blade leaves excess ink on the roll, a printer quickly loses control over quality and consistency.

Corrugated Doctor Blades Through the Years

1960s – Straight UHMW

About 50 years ago, corrugated printers started using doctor blades as a replacement for rubber rolls to gain control over the amount of ink transferred to the plate. (Read:“Corrugated Ink Deliver Systems: Two Roll or Doctor Blade?) UHMW offered a good solution because its dense molecular structure was ideal for printing environments that combined long runs and coarse anilox engravings. This soft, thick material was safe to handle, didn’t score anilox rolls, and was highly resistant to stress cracks and chips. It was also very abrasion-resistant which gave the blades extremely long life. UHMW products were engineered in thicknesses of .090” and .100″ which was adequate to produce the type of work being done at that time (and still in many applications today) – simple solids and lines in one to three colors.

Late 1980s – Early 1990s – Introduction of Bevels

As packaging began to take on more of a marketing role in the 1980s, the demand for higher quality graphics grew. Doctor blades became common in corrugated applications and new press technology, including ceramic anilox rolls and doctor blade chambers, came to market. Blade manufacturers focused on developing stronger, more durable materials that could be engineered into thinner products. Blade thicknesses decreased to .060″ and .080″, and 30° and 45° bevels were introduced to allow a smaller area of contact with the anilox roll.

Late 1990s – Early 2000s – Plastics and Composites with Finer Bevels

Packaging requirements continued to increase in the 1990s, and there were more innovations in anilox rolls and press components. Printers began using more advanced plastic materials for a stiffer, more durable alternative to UHMW.  Acetal blades were effective at metering moderate to high line screen rolls while providing great chemical resistance, good dimensional stability and a low coefficient of friction. These materials could be fortified with additives such as Teflon and manufactured into thicknesses of 020” to .040”. The material was able to accommodate finer bevels of 15° and 22° to produce difficult fine type and reverses. Tight weave fiberglass composites were also developed for screen and process work due to their extremely stiff and durable characteristics.

Mid 2000s – Next Generation UHMW

For printers using UHMW to produce low to moderate graphics, Flexo Concepts introduced a new high-density formulation UHMW to deliver up to 25% longer blade life than traditional UHMW. This next-generation formula was capable of producing enhanced graphics for a longer wear period and is still widely used today.

Today – Next Generation Polymers with MicroTips

Nowadays, box makers are asked to produce packages that serve as both shipping and display vehicles. Graphics requirements are exceptionally challenging and more colors, finer plate screens, half-tones and higher anilox line counts are being used to produce attractive point of sale and point of purchase containers. Predictable ink density and color control are essential to ensure manufacturers’ brand consistency. Until recently, steel had been the only blade that could meet this performance criteria. In 2012, a new blade that offers the best of traditional non-metallics and steel was created for these applications. Flexo Concepts’ next generation polymer blade with a unique MicroTip™ is capable of metering the highest line screens as well as a steel blade for the most demanding graphics requirements (read: “New Polymers Meter Like Steel Doctor Blades”). The MicroTip wears slowly and evenly and delivers consistent ink film thickness for the duration of the print job.

Along with press builders and anilox roll manufacturers, corrugated doctor blade suppliers have done their job of “keeping up with the times.” Blade materials and tip configurations have advanced over the past half-century along with the demands of the packaging industry. While UHMW, traditional plastics and composites are still the best choices in many low-moderate graphics applications, corrugated printers who want to avoid the short blade life and risks with using steel now have a next generation polymer blade to produce the highest quality work.

Request a TruPoint Orange Doctor Blade Sample

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Are you experiencing Pin-holing and Production Pitfalls? Part I

why-in-the-world

 

Flexographic printing technology, like all other printing technologies, relies on the transfer of ink to a range of substrates. With flexography, that transfer begins with the anilox roll, which is designed to enable a controlled, predicatable transfer of ink to the plate surface. Ideally, the ink is transferred to the surface of the plate as a series of dots, but in reality, rotation of the anilox roll often turns the dots into ridges. So the ink transferred from the plate to the substrate can contains ridges and voids—otherwise knows as pin-holes.

Because the ink layer is not continuous, the printed piece suffers from a loss of density and color vibrancy. To get the highest possible density with the least amount of ink, the ink needs to be printed in a thin continuous layer, with no voids. If you can accomplish this, the light from the source reflects evenly and continuously to the observer—in this case, to the consumer viewing packaging on the shelf. But trying to apply more ink to counteract the problem increases drying times and slows presses down, and applying more impression to increase the density results in compressed highlights and reduced tonal reproduction.

More ink also requires the use of a higher volume anilox roll, but these rolls often have lower LPI value, with bigger cells and a larger gap between the centers of each ink dot. What you get then are potentially larger voids between the ridges of ink.

Over the years, several approaches have been developed to try to eliminate pin-holes in flexographic printing. One such approach is to reduce the amount of gap between the anilox cells on the roll. This can also increase the ink flow, but there are production limits on how much this can be done. Another option is to change the surface of the plate, which typically involves creating small cells in the surface of the plate that carry ink in an attempt to transfer more ink to the substrate, but this increases ink use, drying demands, and slows the presses further.

Another newer alternative is to use a specific imager technology to apply a texture pattern on the surface of the plate, like regular rectangular islands surrounded by a thin sea of ink that breaks up the cell pattern from the anilox roll. By breaking up the anilox pattern, it breaks up the pin-hole pattern, and significantly improves the ink transfer.

By breaking up the pattern, this solution allows the transfer of the ink in a smooth layer without the large pin-holes, resulting in cleaner brighter colors, and higher densities, with the same or lower ink laydowns. Also, it should be noted that contrary to popular belief, solid densities are impacted more by the smoothness and eveness of ink laydown than they are by the actual volume of ink transferred, and increased densities with lower ink laydowns allow for better overprints for cleaner and brighter expanded gamuts, without adversely impacting drying times or press speeds.

The key is that better ink transfer allows printers to achieve their target densities, generally eliminating the need to chase density with more ink, more pigment, and more pressure. These features alone often allow printers to achieve greater color gamuts, better print quality, higher print speeds, and greater consistency.

So how do you modify the plate surface to create these surface texture patterns? With the right technology, it’s a fairly simple process that yields impressive results and opens up many more opportunities for flexographic printing.

Learn more on the technology that will prove helpful to address “Pin-holing and Production Pitfalls” you may experience – read Part II of this series next week.

Dr. John’s Contact Information:

John-Anderson-AugFor anyone who does want to email me, please use john.anderson3@kodak.com and please don’t miss out the number 3 in the address, or you will reach another John Anderson in Kodak manufacturing!

Have a wonderful day,
Dr. John

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Filed under Print Defects, Printing