The TruPoint Orange doctor blade can successfully eliminate UV ink spitting and start-up lines, reduce the frequency of blade changes and offer a safe alternative to steel blades. However, proper installation is the key to its success. Three important factors to keep in mind when installing TruPoint Orange are handling, orientation and pressure.
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Installing your TruPoint Orange doctor blade incorrectly will result in disaster. Well, not really. But it will create headaches for the press operator and waste valuable resources. It will also prevent you from getting the maximum value from your doctor blade investment.
The TruPoint Orange doctor blade is a lifesaver in many pressrooms when it comes to eliminating UV ink spitting and start-up lines, reducing the frequency of blade changes and offering a safe alternative to steel blades. However, the blade requires a bit more finesse than steel when it’s being installed in order to work its magic.
It goes without saying that the surface the blade will rest on should be clean, so the blade can firmly rest against the blade stops. Also, tightening the blade clamp screws starting in the middle and working outward is a good way to get a uniform fit.
But, if we had to name the three most important factors to keep in mind when installing a TruPoint Orange doctor blade, it would be handling, orientation and pressure. That’s not to say that other considerations such as angle and alignment aren’t important. It’s just that these particular variables, if not executed properly, will almost always foretell the failure of the blade.
A press operator should take care to protect the integrity of any doctor blade (and his or her own safety when using steel) during blade transit, storage and installation. But particular caution should be exercised to keep a MicroTip® edge from coming in contact with anything that may damage it.
The MicroTip on an Orange blade is amazing in its ability to achieve and maintain a fine area of contact with the anilox roll 
surface. After all, this is the driving force behind the blade’s ability to match the metering performance of a steel blade. Its material is also incredibly tough, able to stand up to the abrasiveness of even the harshest chemistries like high titanium white inks and special coating formulas. But some of the same characteristics that give the TruPoint Orange doctor blade its awesome wiping power and durability also make its MicroTip vulnerable to nicks when handled or stored improperly. Once the edge is compromised, the blade can cause printing defects such as continuous streaks, marks and lines on the substrate. Keep the blade safe and always run your finger along the leading edge of the blade to ensure no imperfections are present before locking it into place. (Remember, there is no danger of cutting yourself with a TruPoint Orange doctor blade!)
To reap the full performance benefits of the TruPoint Orange blade, the blade must be installed with correct orientation. When 
they are manufactured, TruPoint Orange blades are imprinted with text to guide you when you install them. It is important that the MicroTip edge is pointed away from the roll, with the text facing towards you and the arrows pointing to the anilox. It’s simple – if you can’t read the text, the blade is installed the wrong way. A blade that’s installed “backwards,” (with the MicroTip facing towards the roll), will not make even contact along the anilox roll and result in streaking on the printed piece. If your Orange blade is beveled, the bevel should face the inside of the chamber, or away 
from the roll, when properly installed. If using a doctor blade chamber, the containment blade should be the first to touch the anilox roll and the metering blade, second.
Assuming a doctor blade chamber is properly aligned, much less blade pressure is needed to get a clean wipe of the roll with a plastic doctor blade than with a steel one. For best results, find the minimum amount of blade pressure required to contact the anilox surface when installing TruPoint Orange. Unlike with steel, TruPoint Orange should generate few or no streaks on the anilox when starting up. Minimizing blade pressure against the anilox roll will not only ensure print quality but also extend blade life (and end seal life if applicable).
A good way to gauge the correct amount of doctor blade pressure is to look at the roll
once it’s inked. Before the clamp is tightened, the anilox roll will appear glossy – a sign that too much ink is remaining on the surface. Blade pressure should be increased gradually until a satin finish appears on the surface of the roll. A dull sheen is a good indication that the correct amount of pressure has been achieved and the doctor blade is effectively shearing the excess ink from the roll. If pressure is increased beyond this point, the doctor blade edge will bend, and contact area with the roll will grow. The anilox surface will begin to look glossy again or show light streaks or lines because it is being flooded with too much ink. At this point, lessening blade pressure, rather than increasing it, will alleviate the issue.
When a TruPoint Orange blade is installed properly, its metering power is brilliant in terms of executing consistent print quality over the life of the blade. Take care to ensure the three key elements of success – proper blade handling, correct blade orientation and the right amount of blade pressure – and your TruPoint Orange doctor blade will likely become your press operator’s new best friend.
After years of being relegated to jobs with low graphics requirements, flexography now rivals other printing methods for quality and efficiency thanks to advances in the ink delivery process. Specifically, doctor blade chamber systems allow for better control over ink film thickness, color consistency, ink consumption, cleaning costs and press run time.
A chamber doctor blade system uses two doctor blades along with an enclosed ink chamber to dispense the ink to the anilox roll. The reverse angle blade acts as the metering blade and wipes excess ink from the anilox roll, and the trailing blade acts as a capture or containment blade and holds the ink within the chamber. Foam, rubber or felt gaskets seal both ends of the chamber and keep ink from leaking out.
The enclosed chamber design provides protection from evaporation of solvents or amines from the ink, depending on whether the ink is solvent or water-based, so a printer can maintain ink viscosity. Also, the ink is sheltered from dust, and slinging and skimming on the surrounding area are minimized. Better control over ink usage means lower ink consumption by as much as 15% per year. The system holds less ink than open pans, so there is less leftover ink at the end of a press run, and this ink can be removed and stored for future use.
Doctor blade chambers also allow for a more efficient and eco-friendly cleaning process than open ink systems. A smaller amount of cleaning solution and water are needed, so cleaning solution and water usage are reduced along with disposal costs. Color changes are quick, speeding up changeover and setup time on a run.
Recently, chamber producers have incorporated innovative engineering concepts and next-generation materials to improve the equipment’s performance and usability. New carbon-fiber constructions are lightweight, strong, durable and temperature-stable, and they reduce press vibrations even on wide format presses. Their surfaces are coated with resin to provide anti-static, corrosion-resistant properties. Advanced clamping systems, like TRESU’s E-Line and P-Line Systems, replace screws with eccentric and pneumatic apparatuses, respectively, to make blade changes faster and easier for operators.
Early chamber systems were designed for use with steel blades. But, to address the increasing demand in the industry for plastic doctor blades, TRESU worked closely with doctor blade manufacturer Flexo Concepts® to develop the exclusive new Series XL Blade Holder. The interchangeable
quick-change clamp apparatus can accept slightly thicker TruPoint® plastic doctor blades, giving printers access to a much wider variety of blade options. Those who prefer plastic blades over steel – whether to improve safety, extend blade life or solve press problems like UV ink spitting – have the flexibility to use plastic or switch back and forth between materials based on job requirements.
When selecting a doctor blade chamber, there are several factors to consider in order to maximize the return on investment. The doctor blade chamber and its loading system should prevent blade misalignment and ensure even contact across the face of the anilox roll. It is also important to make sure that the system allows operators to adjust pressure between the doctor blade and anilox roll. Minimum pressure, particularly when using TruPoint blades, is important to optimize print quality, prolong blade life and preserve anilox integrity.
Today’s flexo printers are able to produce attractive packaging in a cost-effective way thanks in part to the benefits provided by doctor blade chambers. These enclosed systems contribute to high print quality and bring considerable efficiency and cost savings to the pressroom. Along with cutting-edge press, ink, substrate and doctor blade innovations, advances in chamber technology have further improved the ink delivery process, making flexography a viable option for today’s most demanding print applications.
Proper alignment of your doctor blades(s) to the anilox roll (or any roll being wiped or cleaned) is critical to the performance of any ink or coating metering system. This alignment plays a pivotal role in preventing premature doctor blade and anilox roll wear, reducing leaks, and minimizing downtime. Let’s dive into the key aspects of blade alignment to optimize the performance of your process.
Doctor blades are designed to remove excess ink from the surface of the anilox roll. To achieve this, it’s imperative to maintain consistent, light contact between the doctor blade and the anilox roll along its entire face. Variation from this ideal contact can lead to problems including inconsistent transfer of ink or coating to the substrate and premature anilox roll wear.
Several factors contribute to inconsistent contact between the doctor blade and the anilox roll:
Deviation from proper alignment often shows up as uneven ink or coating thickness. Frequently operators try to overcome this problem by increasing blade pressure to compensate for the underlying issue.
This quick fix may temporarily address ink or coating problems but will eventually cause accelerated wear of both the doctor blade and anilox roll. Accelerated blade wear means more frequent blade changes and increased downtime. Accelerated wear of the anilox roll can lead to uneven or inconsistent ink or coating density.
Pro tips: When aligning a doctor blade chamber (dual blade), remove end seals to create an unobstructed view of blade and anilox contact.
A feeler gauge (or business card!) is a great tool to help compare blade to anilox pressure.
Maintaining proper doctor blade to roller alignment is fundamental to optimizing your ink or coating metering system. Avoid the temptation to increase blade pressure to overcome misalignment as this can lead to shortened blade life and accelerated anilox roll wear.
By investing a few minutes in checking your setup, you’ll reap long-term benefits in terms of time, cost savings, and reduced waste. Remember, a well-aligned chamber ensures your doctor blade performs at its best, delivering exceptional results.
