Tag Archives: flexography

3 Tips to Prevent UV Ink Spitting

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by Doug Jones, Apex International

UV inks are considered by many to be the most popular in the narrow-web space.  And for good reason.  Print results with UV inks are consistently better than those using water or solvent-based inks.  But the use of UV inks is not without its challenges.  Chief among those challenges is the issue of spitting.

There are several theories as to why spitting occurs with UV inks and not with water or solvent inks.  Generally, these revolve around the higher viscosity of UV inks comparied to water or solvent and the impact it has on the doctor blade.  Specifically, the higher viscosity can move the blade just enough to allow more ink than is intended to slip through.  Other theories suggest that anilox cell type, viscosity, press speed and doctor blade specifications all play a role.  Regardless, the results can be a disaster, particularly at high speeds.

Ink_Spitting_1

While exactly why spitting occurs is a subject for debate, what is not in dispute is that the relationship between doctor blade and anilox is at the core.  If spitting is creating a challenge in your shop, try these tips for better print results:

1. A stiffer doctor blade may prevent excess ink from getting under and transfering to the plate and substrate.

Testing shows a thicker blade will minimize UV spitting because they resists hydroplaning and do not allow texcess ink to transfer to the anilox.

2. Try a 30° anilox cell with openings

The ink can move through the openings in the anilox cell walls preventing ink from being built up onto the back of the doctor blade.  (Situation 1a).

Ink_Spitting_2

A word of caution: This solution is only temporary. Because the roll will wear over time, the openings will become smaller and eventually disappear. So over time you will get the same situation as with the regular anilox roll. Ink will built up at the back of the doctor blade (situation 1b).

3. Try GTT Channel engravings.  

There is no pressure built up at the doctor blade because the ink can move through the GTT channels. Therefore no ink builds up onto the back of the doctor blade and no ink drops from the doctor blade onto the flexographic plate or substrate.

Ink_Spitting_3

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Filed under Anilox Rolls, Print Defects, Printing

Cut Print Production Cost & Improve Quality and Consistency

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From the time Printing has been accepted as a means of communication, the effort has been to transfer ink from the tray to the substrate. There have been consistent developments and the target has been to improve the quality of fixed palette or expanded gamut print, for short or long run.

apex-print-quality

Different printing processes also developed to suit the printing of various substrates. All the printing processes have some common factors. These are:

  1. Transfer ink from a tray(container) to the substrate.
  2. Use the correct shade of ink to get the correct shade in print.
  3. Use the correct volume to get the correct depth.
  4. Distribute the ink uniformly to get even colour across the substrate and to get the correct tonal gradation.
  5. To use the best resolution possible on the press. This is not always true. As there are presses that can print higher resolution, but even than lower resolution is used:
    1. To suit the substrate being used
    2. To be safe with a lower resolution
  6. For multicolour printing to use CMYK + pantone inks of the correct hue and density for correct colour reproduction.

To achieve the above objective every effort has been directed towards improving the depth of the colour and range in print. In the process a higher volume of ink is being used that produces a thicker layer on the substrate and requires more energy to dry.

One look at the recent development that have taken place in the Flexo industry will show that all the photo polymer plate manufactures have tried to:

  • Target improved ink transfer in the solid areas to improve the ink transfer(increase the ink volume) to get a higher solid colour depth.
  • Trying hard to hold a finer dot(of 1% and below) of a finer screen ruling on plate, at a higher plate and equipment cost that add to the cost of processing the plates
  • This capability is limited to the use of special plates and software meant for use with these equipment.

All these require higher investments and add to the cost of production.

Almost all anilox roll manufacturers have tried to create a higher cell volume with finer screen rulings so as to provide the required depth of colour in the solids when using the finer screen on plate.

The time has come to look at the possibility of changing this by:

  1. Using standard lower density inks for most jobs, improving the printing of the highlights.
  2. Using a more uniform and thinner layer of ink, without losing the required print densities
  3. Improve press speed and production capacity
  4. Improve the colour gamut in print while eliminating the need to use pantone shade inks
  5. Black ink uses carbon as the main ingredient. The reduction or elimination of black ink in print makes printing more environment friendly and provides you with carbon credits. It makes packaging of food more healthy and less toxic.

That helps reduce the cost of printing, while producing a greater depth in colour, improving the print range and reducing the energy to dry the thinner layer of ink. When you do this change you:

  1. You eliminate the inventory of Pantone inks
  2. The make ready time required to match the colour in print, on the press. It also reduces the cost of wasted /unused Pantone shade inks in stock at the end of the year, every year.
  3. Reduce the anilox inventory and use the same anilox rolls for almost all jobs.
  4. Reduce the overhead costs, with reduced press down time, as you use the same anilox rolls for the same colour on the same station.

One notices that Gravure printing is able to achieve the highest print densities even though they use liquid inks, while in Offset printing the ink densities are the lowest. This is because the ink layer laid on the substrate, in offset, is the thinnest.

If we are to reduce the density of the inks we use in printing than the cost of the inks would come down. By reducing the ink density we are reducing the density of the highlight areas. This will reduce the effect of dot gain in the highlights, which is a major problem in flexo printing. This small change will enable us to print the fine highlight details easily and cleanly. It will also allow us to print the vignettes smoothly even when we use coarse screen with coarser screen anilox rolls. Even though the coarser screen anilox rolls use a higher cell volume and will provide a thicker layer of ink, the lower density in the highlights will reduce the effect of the dot gain to the eye and provide the required softness to the image.

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Enhancing the Colour Gamut in Fixed-Palette Printing

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by Doug Jones & R S Bakshi

Multicolour or fixed palette printing is generally associated with printing with 4 process colour inks namely CMYK. Sometimes it also uses additional Pantone shades, to produce a colour shade that is not reproducible using the CMYK process colours. This system has been in use for many years and is still in vogue. In many cases, higher density inks have been used to improve the printing of process colours by using higher density inks to produce the richer/darker colours. Though this helps to improve the richness of the colours, it makes the highlights darker in print which can at sometimes be drawback.

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There have been attempts to improve the printing of process colours by printing 6 colours namely CMYKOG which came in very powerfully, but somehow never gathered momentum.

Thereafter another system came in with improved capabilities. Over the years that team has worked very hard to improve its performance, in more ways than one. The present system if fully equipped to help the printer get full benefits, by using this system.

Of late, there has been a lot of interest in creating awareness in following the 7 colour system of printing, with a consortium of companies coming together to focus on this system, now known as the REVO project. I think this is a good move as it will benefit the printers, substantially, to follow this system of 7 colour printing, as a standard practice. This principle of 7 colour printing, can be practiced independently of the companies of the consortium and a printer is free to choose the partners it he wants.

The best part of the system is that it gives the pre-press department, the ability to convert the RBG/CMYK image into separations for CMYRGBK, within no time, that enhances the Colour Gamut reproduction which is very easily seen on the monitor itself. This is the only software, I have seen, that can do this without batting an eyelid. Earlier we used to spend hours in trying to prepare a separation for printing a Pantone* shade to combine with the CMYK image, by manipulating the CMYK image separations. The system also allows you to edit the separations, to an extreme, that I have not seen before. Also the editing functions are simple and easy to manage.

The improved Colour Gamut that one sees on the monitor can be easily reproduced using the defined set of inks. It also improves the appearance of the metallic colours like gold and silver which is really amazing. The use of the ink suggested can also be used as standard for printing of all jobs, irrespective of the printing process or substrate used. The essence is to use a good white substrate with the standard set of inks.

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The names used in this article with an * are the registered Trade Marks of the individual companies.

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Flexo’s Future – Expanded Color Gamut

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by Richard Black, All Printing Resources, Inc.

The Flexographic print process has long been thought of as a simple print process, not capable of the same quality as the lithographic print process. In the last five years there have been many advances in plate technology, digital platemaking process, and screening that have dramatically improved the quality of Flexo. It is very common today for converters to run 150 lpi, and many have made the jump to 175 or 200 lpi along with the ability to fade screen vignettes to zero. These specifications would have been virtually impossible a few short years ago.

Is ECG Just the Latest Trend?

The ability to print fine screen rulings and fade screen vignettes to zero have made a resurrected technology possible, printing with an Expanded Color Gamut (ECG). ECG printing has been around for quite some time. The Lithographic industry has been using it, in limited areas, since the early 1990’s. Matter of fact, in an article written by Don Hutcheson for the 1999 GATF Technology Forecast (www.hutchcolor.com/PDF/HiFiupdate98_2000_04.pdf) the following Extended Gamut systems (then called HiFi Color) were commercially available in 1998:

  • Hexachrome (CMYK+OG) – Pantone
  • MaxCYM (CMYK+CMYK) – Royal Zenith and then the basis for DuPont’s HyperColor
  • Opaltone (CMYK+RGB)

Why Are We Talking About it Now?

FLEXO Magazine Cover - Oct 2014 Expanded Color Gamut - CMYK+OGV

FLEXO Magazine Cover – Oct 2014 Expanded Color Gamut – CMYK+OGV

So, if the technology has been around for so long, why is everyone in Flexo just now talking about it?  The main reason is the ability to reproduce a majority of spot or Pantone colors using only 7 inks, CMYK+OGV. This has recently been demonstrated with the 2014 & 2105 fall covers of FLEXO Magazine.

Last October the front cover was printed Flexo using 7/color ECG and the back cover was also printed Flexo using standard 4/color process. The color difference and Pantone color match was amazing using the 7/color ECG process.

The 2015 November cover of FLEXO Magazine was again printed using the 7/color ECG process but this time it was compared to a 4/color cover printed using litho.

Award-winning connections

Gidue Wins 2015 FTA Innovation Award

Gidue Wins 2015 FTA Innovation Award

We (APR) were lucky enough to be involved in both projects. Earlier this year Gidue (now Bobst) was notified that they had won the 2015 FTA Technical Innovation Award. The award was presented to Gidue at the FTA Forum/InfoFlex in May.

The FTA asked Gidue if they would like to participate in printing the November cover of FLEXO Magazine using theGidue M5 Digital Flexo Excellence Press located at the APR Technology Center (located in Glendale Heights, IL), along with the 2014 FTA Technical Innovation Award Winners,Esko Equinox and SpotOn! Flexo. Gidue agreed and project planning began. The goal of this project was to demonstrate the quality of 7/color ECG printing versus normal 4/color process printed litho.

Putting it all together

In August, APR hosted 12 industry-invited personnel, plus a few of us at APR, to print from scratch, the November cover of theFLEXO Magazine. This meant we needed to Optimize, Fingerprint and Characterize the Gidue press prior to actually printing the cover. This process required 4 press runs and 16 plates before we had the proper information to create the profile and the final 7 plates required for the cover. The process is intense but the results are amazing.

Below is an example of the 4/color Litho cover versus the 7/color ECG Flexo cover printed at APR.

FLEXO Magazine Cover - Nov 2015 Standard Process Color - CMYK

FLEXO Magazine Cover – Nov 2015
Standard Process Color – CMYK

FLEXO Magazine Cover Nov 2015 Expanded Color Gamut - CMYK+OGV

FLEXO Magazine Cover Nov 2015
Expanded Color Gamut – CMYK+OGV

 

 

 

 

 

 

 

 

 

 

You can see how vibrant and colorful the 7/color ECG cover is compared to the normal 4/color cover. Also note the Purple in theFLEXO masthead, as well as, the green and yellow side bars. These areas are spot colors that would normally have to be run in their own print station but with 7/color ECG process you can reproduce these and virtually any other color.

The November FLEXO Magazine debuted November 3, 2015 at the FTA Fall Conference in Columbus, OH. The following link will direct you to the electronic version of the 12-page article that appears in the magazine.

http://digital.realviewtechnologies.com/?xml=Flexo#folio=17

These two magazine covers demonstrate that the 7/color ECG process is viable and the products/technologies required for this process are commercially available.

Industry-wide acceptance of Expanded Color Gamut

Pantone Extended Gamut Guide

Pantone Extended Gamut Guide

Another major step forward in the acceptance of the 7/color ECG process happened in September when Pantone announced a newPantone® Plus Series Extended Gamut Coated Guide printed using the 7/color ECG process. www.pantone.com/what-is-extended-gamut

For years we (the printing industry) have shown content creators and designers the Pantone Plus Series Formula Guide®, and said you can pick any 2 or 3 of these colors, that we would run as a special or spot color. With the new Extended Gamut Color guide, content creators and designers can pick as many of these color as they want!

 

Hands-on experience with Expanded Color Gamut Printing

APR & Esko ECG Seminar Sample Job

APR & Esko ECG Seminar Sample Job

Earlier this year, Esko and APR held an Expanded Gamut class where we produced a series of labels printed on the Gidue M5 press using 200 lpi and Esko’s Full HD Flexo & Equinox technologies both in 4/color process and 7/color ECG.

The results were amazing. The 7/color ECG labels faithfully reproduced all 15,  yes 15 Pantone colors. So imagine if this was a commercial job and the customer asked you for a label with 15 Pantone colors, what would you do?  It’s not IF ECG will become the standard for Flexo printing it’s WHEN, and the when is quickly becoming now!

Kind of makes you scratch you head doesn’t it

To read the original article, visit https://www.teamflexo.com/flexos-future-expanded-color-gamut/?

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Corrugated for Retail-Ready Packaging & the Technical Problems that may Arise when Flexo Printing

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By Tom Kerchiss, RK Print Coat Instruments Ltd

 

The Retail-Ready packaging (RRP) concept has boosted the demand for corrugated/micro flute systems; a situation that is set to continue as major retail chains and superstores not only in North America, Europe and Australasia but also in the Far East adopt RRP with enthusiasm.

Retail Ready Packaging makes economic sense for high volume retailers, especially at a time when many of the major superstore groups have seen forecasted profits fail to materialise and shareholders and city investors become more insistent that economies are put in place and operational efficiencies are made. RRP aims to reduce product handling, increase speed of replenishment, reduce packaging material and costs and improve shelf display. RRP and high quality printing should go hand in hand as the concept is designed to reinforce product branding throughout the supply chain. Over 80 per cent of the product should be visible on the shelf and primary consumer information, which normally goes un-noticed unless the product is picked up and handled, is made highly visible on the retail ready tray.

Corrugated material and folding carton are in many respects ideal display and packaging mediums for RRP. If we just consider corrugated for the moment it combines both strength and rigidity with the flexibility to absorb shocks, corrugated board also makes good use of minimal material. There is hardly any other material that this author is aware of that gives such rigidity using so little material. These interesting properties are obtained by gluing various layers (at its basic), an undulating middle layer (flute) with plain layers on either side: the result of which is a light and rigid framework, the principle of which has been adopted by the aero industry in wing construction and in civil engineering in bridge construction.

In many instances today – Retail Ready Packaging arguably being one of them, the consumer will not always even be aware they are encountering a corrugated medium. The reason being that the characteristics of the material and its presentation have changed so much in order to meet not only the self- service requirements of the modern retail environment, but also the requirements of brand owners. In this case the brand owner and marketing organisation may be seeking to either promote established premium products that need a high volume of packaging featuring ultra high quality printing to support the brand and attract attention, or perhaps newer or promotional products that will be shipped in low volumes, packed in high quality printed boxes with the shelf appeal to generate demand. Even low cost commodity style products that need high volume cost effective boxes with fewer colours and less elaborate branding benefit from the RRP approach, bottled sparkling/natural and flavored waters serve as an example.

In corrugated applications the substrate plays a major role in dictating how the ink is going to appear on the finished job. Much of corrugated board is printed flexo, either directly onto finished board or as is most often the case when presentation is important via pre-printing on the outer layer or liner or by laminating. Defects that can occur during the corrugating process may impact on print quality and on production rates. These defects are associated with flute integrity, caliper, wash-boarding and warped board. Ink formulation, photopolymer plate selection, anilox and inking systems must be chosen or formulated with care if print quality and workflow consistency is to be maintained.

The technique of pre-printed liner has revolutionized decorative possibilities. It is however expensive, to make it economical pre-print tends to be considered for longer runs and where a prestigious impact needs to be considered. Another option is to laminate a pre-printed liner, giving the best results since printing can be undertaken on the highest-grade paper. Again an expensive option but recommended where high value consumer goods are being sold. In a RRP situation pre-printed liner and laminated would tend to be confined perhaps to big-ticket gift items, electrical and home/garden furniture goods.

Although the introduction of pre-printed liner and laminated materials as well as an increasing number of engineered flutes have undoubtedly changed printing board, a degree of watchfulness and care may be necessary when for instance flexo printing some jobs as the medium can be challenging.

The substrate can play a major role in dictating how the ink is going to appear on the finished job. Absorption and surface tension are the main factors that influence print density as well as drying, trapping and dot gain. It is also important when providing a customer with s colour match that the exact same substrate is the one that is finally to be used.

Printing one colour on Kraft, mottled or even clay-coated sheets that seem to have the same surface appearance will yield a wide range of shades even from the same colour. The reason for this is that the sheets with a high level of absorption produce a weaker colour due to the ink being absorbed into the substrate. Conversely those sheets with lower absorption properties will display stronger colours; if clay coated sheets are used the ink may not even penetrate the substrate surface. Surface tension plays a role in determining colour strength.

If the situation arises whereby it is necessary to print on clay-coated board, insufficient coverage or poor trapping may well occur together with poor adhesion due to the components of the ink having a combined surface tension that is higher than that of the substrate. This produces a cohesive effect, causing inks to shy away from some areas of the substrate surface and produce an uneven appearance to the final print. Inks with a higher level of polymeric additives and incorporating a measured amount of water can be used to good effect. In this instance the water is added at the press side to reduce viscosity so that faster drying and faster press speeds can be obtained. Care must be taken as too much water causes an imbalance in the ink, reducing rub resistance and gloss. A diluting vehicle will maintain ink balance.

The rub resistance that printed ink exhibits in some instances may well have to be modified. For example: Kraft, mottled and bleach board tends to show more rub resistance than a clay -coated board. Rub resistance is adjusted with waxes and specific polymers and a sample preparation or colour communication device such as the FlexiProof is ideal for monitoring results as well as for product development including inks and substrate. The FkexiProof 100 or variants FlexiProof UV and FlexiProof UV LED are also suitable for conducting tests associated with rub, wear resistance, scratch resistance, gloss and other desired properties.

On a clay coated board the ink supplier needs to be aware if the board is going to be overprinted with a varnish. Normally if complex graphic printing is undertaken on a clay-coated medium the varnish is added for protective barrier purposes and for gloss. It would be counter-productive to add a wax additive as this would not only reduce the gloss but cause problems with a solid over solid trapping.

The pH of inks used for graphic printing on clay-coated board is generally higher than for Kraft board. The reason for this is that the inks tend to incorporate more in the way of polymer and the inks contain a balanced level of water. The higher pH helps stabilise the ink and helps make it stay open longer, slowing the drying of the ink on the printing die. A lower pH range is advisable for Kraft type boards because these are generally printed at faster speeds and quick drying is necessary.

Adjustment of pH is usually done with amines or ammonia with the former being the most stable and the latter not being recommended because of potential health risks. The one constant is that the ink pH must be checked from time to time to prevent changes that may arise due to evaporation. A pH stable ink is the best option requiring much less in the way of attention.

For more information, visit  RK Print at www.rkprint.com

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Three Secrets to Prolonging Anilox Performance

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Even the highest quality anilox rolls need proper care in order to maintain their performance.  And because the anilox is considered by many to be the heart of any flexo press, the importance of regular cleaning and maintenance cannot be overstated.  The anilox is a precision instrument that drives the efficiency and consistency of your printing process.  Take care of your anilox and they will take care of you.

Here are three ways you can ensure maximum endurance and performance from your anilox.

Proper care begins when the anilox arrives

Inspect any new roll that enters your facility immediately.  Check to make sure the crate is undamaged.  Remove the roll from the crate and inspect it thoroughly.  Be sure to identify any dings, dents or scratches on the roll.  “One of the biggest mistakes a printer can make is simply adding an uninspected roll to inventory, particularly if it arrived in a damaged crate.” says Doug Jones, Vice President of Marketing at Apex International, the world’s leading supplier of anilox and meter technology.  “By identifying issues early, anilox companies are often able to help correct the issue before it disrupts print production.”

Use care while installing the anilox into your press

Remember that anilox rolls are precision instruments and must be handled with care.  Never leave an anilox roll resting on its engraved surface as doing so could break down cell walls and cause scoring or streaking.  Instead, always support the anilox by its journals.  While installing, cover the body of the anilox with a wrap or covering to protect it from impact damage.  It is also important to remember that ceramic, while durable, is not impact resistant and can chip.  Chipped ceramic on the ends of an anilox can lead to ink and solvent leaching which ultimately reduces the life expectancy of the anilox.

Use and Storage

Anilox rolls are not a “set it and forget it” component.  Once the anilox is installed, never run the anilox dry with the ink chamber against the roll.  Doing so can cause excessive doctor blade wear and potentially score the anilox.  Keep the roll running while ink is in the chamber to prevent standing ink from drying in the anilox cells.  If plugging does occur, never use tools to try and removed dried ink.  Instead, follow a proper cleaning schedule that includes chemical cleaners with a pH between 6.5 and 10.5.  Never use chlorine, ammonia or any cleaning solution that is 100% acidic as these will corrode your anilox.  Finally, store the anilox either covered on a rack (to prevent contaminants such as dust from entering cells) or in its original crate, taking care that the surface is 100% clean and dry prior to storage.

Following these simple guidelines can help prolong the life of your anilox roll, which can easily exceed 2 years depending upon care and environmental variables such as humidity.

About Apex
Apex International, headquartered in Hapert, The Netherlands, is the leading manufacturer of anilox and metering roll solutions in the world. The Company employs approximately 300 people and serves over 5,000 active customers in all markets (corrugated, narrow-web, wide-web, offset and coating applications) on a global scale.  Apex operates five production facilities and seven sales offices worldwide, providing a local presence for customers and a global network to serve multi-location businesses and multi-national corporations. www.apex-groupofcompanies.com

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Optimizing Fixed Palette: The Future of CMYK

By Doug Jones – VP Global Marketing Apex International

Recent studies and trials aimed at optimizing Pantone simulation suggest that the fixed palette approach is ready to revolutionize the flexography and label industries.  The change is due specifically to advancements allowing for unprecedented process control and consistency as well as the development of new tools designed to pinpoint which process parameters are failing so they may be addressed before problems arise.

A recent trial by Soma Engineering in partnership with Apex International has provided hard data supporting the idea that process variable elimination and optimization of remaining processes is the key to maximizing the number of Pantone simulation possibilities using 4 color fixed palette.  The study also produced data comparing the 4 color fixed palette to 7 color.  The trial was conducted on a Soma 8 color gearless press OPTIMA.

“Using CMYK plus Orange, Green and Reflex Blue, we were able to hit 1,412 Pantones within a ΔE of 2 or approximately 81% of Pantones.  Comparatively, we were able to hit 1,184 Pantones using just CMYK within the same ΔE.  However, when we included silver we hit an additional 1,184 in metallic Pantones bring the total Pantone simulation to 2,604.” said Nick Harvey, Technical Advisor at Apex International. “We also hit a total of 1,519 Pantones using 7 color and 1,302 using 4 color within a ΔE of 3.  Including metallics, we hit 2,604 Pantones.  I don’t believe any other CMYK trial has gotten close to these targets.”

According to Harvey, 4 color fixed palette has two distinct advantages over 7 color. The first is a matter of variable elimination.  Printers need to determine if the additional 228 Pantones are worth the inclusion of three additional variables.  The second advantage relates to flexibility.  Harvey states that estimated 95% of printers only have 8 unit presses.  4 color fixed pallet allows for inclusion of metallics, various lacquers, double white and other options that create value and subsequently command a higher price point.

The demand for optimized fixed palette is only expected to grow as brand owners demand better color consistency with shorter run lengths and just-in-time production.  Chief among these concerns is the ability to create color consistency across multiple markets ensuring that the same values and same Pantones can be printed on labels just as they can on films.

“Achieving color consistency is probably the most difficult component of transitioning to a fixed palette process.” said Bas van der Poel, Technical Sales Manager at Apex International. “Fixed palette is about control: control over variables, control over ink flow and so on.  It is this control that has allowed us to hit the number of Pantones we have with this trial and do so while not having to make any changes to plate inventory.  It requires a level of control that simply is not possible with conventional anilox rolls.”

Apex International holds globally recognized patents on an award-winning technology that uses continuous lasers to engrave a slalom pattern onto the anilox.  The continuous laser is responsible for creating an anilox product capable of the smooth, consistent and controlled laydown necessary to optimize fixed palette.

“What these trials have shown us is that specific attributes of our GTT engraving perform exceptionally well with fixed palette.  It has a tolerance of 2% on volume and ink transfer.  GTT engraved rolls are 90% opening while maintaining wall stability.  Ink flow is more consistent and unobstructed, subsequently solving spitting issues and producing a controlled, smooth laydown.  All these things contribute to the results we’ve seen with Soma.” said Harvey.

“This project was part of our annual Flexo Challenges Conference, where we address the latest trends in the flexo industry. The result was beyond expectations with significant benefits for the printers as well as the brand owners. Combination of HQ short run press, HQ anilox technology and pre-press knowledge positions flexo technology in much better shape in relation to competitive gravure printing.” said Petr Blaško, Marketing Manager at Soma Engineering.

Apex has also developed a closed loop process that is designed to aid in the implementation of fixed palette. The process involves the use of a calibration roll that guarantees full production control by identifying which parameters are failing so that they may be addressed.

“In many respects the calibration process is just as critical as the use of GTT in fixed palette optimization.” concludes Nick Harvey.

Visit www.apex-groupofcompanies.com or http://www.soma-eng.com for more information.

About the Author:

CA439031-A4B7-4A13-AF46-0268299E4FF5B8F1C2F5-60F2-4C73-9CE4-D8AB3DE23D3EDoug Jones is Vice President of Global Marketing at Apex International, the world’s largest manufacturer of anilox and meter products with 7 locations on 4 continents and sales offices covering over 80 countries.  He holds a bachelors degree in Communications from Penn State and a Masters of Business Administration.  He lives in Sewickely, Pennsylvania USA

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Dr. John Writes: A Blast from the Past – Flexo Print Fault Guides from the ’90s

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During a recent ‘de-clutter’ session at home I came across my 1998 box of materials from the EFTA in England, and took a quick trip down memory lane with a printed copy of the “Typical Flexo Print Faults” guide from Sun Chemical. As I thumbed through it I was amazed at just how BAD the issues looked when viewed through ‘today’s eyes’. I know the guide contained truly bad cases for each defect to make sure the fault was visible, but to some degree these really were daily occurrences back then. It struck me how few of these we see today, and if we do see them, how they are never present to that degree.

The list of “Typical” Flexo Print Faults In 1998 included:

  1. Poor Trap
  2. Ink Smearing / Dot Bridging
  3. Dirty Print / Fill In
  4. Mottled Print
  5. Print Striations
  6. Uneven Colors
  7. Poor Ink Coverage
  8. Pinholes or Fisheyes
  9. Washboard Print
  10. Dark or Dirty Print Color
  11. Ink Foaming
  12. Weak Print Color
  13. Inconsistent Print Color
  14. Dirty Print / Halos
  15. Dirty Print / Feathering

 What’s with all the Dirty Print?

Did you notice that 5 of the 15 print faults involved the words “Dirty Print”, and several of the others could easily be considered in that type of category? It’s sometimes easy to forget that only 15 or so years ago Flexo had a LOT of issues, struggling with lower quality and a highly inconsistent process.

What is also interesting is that the primary causes of these print faults were not due to a single factor; they were due to issues with the ink, anilox, ink supply, plate, doctor blade, operator, substrate, tape and press combined. The improvements that have been made since that time, and that give us the flexo performance we enjoy today, have truly been across the board – though it’s true to say that they don’t always happen in perfect synchronization.

When one supplier comes up with the latest major advance, it often takes time to completely step the industry forward, because no one component is independent of all the others. As an example, and one that’s close to my heart, when new significant improvements in plate capabilities are introduced, they are supported in implementation over the following years by continuous improvements in the ink, anilox, tapes and the press, until they all come together to unlock the true capabilities of the plate – and vice versa.

The Supermarket Test

It used to be that you could walk down the middle of any supermarket aisle, and a wide one at that, and you could spot the flexo printed products on the shelf from 5 feet away. The typical Flexo halo was often the first giveaway, but now that is very much the exception, and you need to get a lot closer than 5 feet to see it!

As an industry we should be PROUD of what we have done, as suppliers, printers, and service providers, we are now as good, and on most days better than the other print processes that we could only dream of matching back in 1998, on a wider range of inks and substrates than ever before. It’s why we mustn’t stop collectively educating our end users, especially those ones that have long memories, about the capabilities of 21st century flexo.

We’ve come a long way in the last 15-20 years – but it’s important to not become complacent and accept that even the Flexo we are printing today is “good enough”. There is always room for improvement and I know that I, for one, will not stop trying.  J

OK, back to those boxes…

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, WW Business Development, Packaging, Kodak

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Anilox Roll Cleaning Essential to Effective Ink Delivery

FlexoConcepts-logo

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
brush_ss_orange_450X268
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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Filed under Anilox Rolls, Cleaning, Printing

Viscosity & pH Control: Increasing Productivity Through Automation

FlexoGuide-600

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