Tresu's chambered doctor blades ensure a uniform, smooth, splash-free and uncontaminated lay-down of flexographic inks and coatings in the anilox roll cells, preventing microfoaming and blistering. Together with the ink circulation systems, they enable accurate pressure, flow and viscosity control, efficient temperature regulation and cleaning, fast blade-changeover and airtight sealing of the chamber. This ensures consistent quality and minimises the need for manual maintenance of the ink circulation during the print process. The systems are suited to printing speeds of up to 500 m/min and cover all narrow and mid-web flexo printing and coating applications.

The Tresu chambered doctor blade technology includes a proprietary, patented rubber Seal System, forming an airtight closure at the chamber sides, eliminating leakage. The airtight environment ensures leftover ink can be stored for long periods without evaporation or perishing.  

Pressure of the ink or coating is maintained at a constant rate so that the pressure of the ink or coating inside the chamber is high enough to create a wall of liquid at the point where the rotating cells meet the blade. This prevents air-bubbles, which can cause ‘microfoaming', from penetrating into the chamber. The chambers feature Tresu's fast ‘E-Line' doctor blade-changing system, enabling blades to be slotted into position and released safely, within one minute, by a clamp.  

Mid-web chambers

For mid-web applications, Tresu offers the FlexiPrint IMW E-Line Chamber Doctor Blade System. It is suitable for solvent-, water- or UV-inks and  virtually all paper, folding carton and film substrates. The unit has an ink volume of between 1.35l/m and 2.2l/m depending on chamber size, and is suitable for anilox diameters between 64mm and 250mm, web-widths up to 1800mm and printing speeds up to 500m/min.

Narrow-web chambers

For narrow-web applications, the FlexiPrint Reservoir Chamber Doctor Blade system has a ‘closed cassette' design. Designed for UV and water-based inks, it has no moving parts and works without a pump. With minimum volume requirements only 0.2 litres, FlexiPrint Combi is built for anilox lengths up to 800mm and anilox diameters ranging from 64mm to 150mm.

The chamber is situated at right angles to the anilox roll, with point-of-contact either in the three o'clock or nine o'clock positions, enabling even ink transfer without suction.  Fast, effortless changeover is possible by sliding and locking the chamber with ease into any position in the printing sequence of the press. Reservoir levels are topped up manually, and human eye judgment is enough to determine when to replenish the reservoir. Alternatively, a float with a sensor can indicate when more ink is needed. The system also features the company's E-Line doctor-blade changing system for safe blade change in less than one minute.

Offset Coating Concept

For sheet- and web-offset printing applications, Tresu offers the Offset Coating Concept. This comprises the Tresu UniPrint Combi chamber doctor blade E-line and Tresu Coating Circulator and a Tresu Coating Conditioner. This system enables sheet-fed and web offset printers to coat printed products at faster speeds, without the risk of micro-foaming. It is suitable for all possible anilox roll up to 1200mm wide and between 80mm and 250mm in diameter, and at print speeds of up to 300m/min or 18,000 sheets per hour. The circulator automatically adjusts to the coating supply and initiates either a 6-minute or intensive 12-minute cleaning program, enabling fast job changes.

Anti-corrosion chamber surface protection

The Tresu CPG Anti-Corrosion surface is a guard that offers surface protection of the chamber doctor blade system. Its aluminium and carbon fibre structure offers resistance against corrosive ink, coating and cleaning liquids. The guard is retrofittable to all Tresu chamber doctor blade systems with the Tresu D4 and D5 profiles.

F10 iCon Ink Supply System

Tresu's new F10 iCon ink supply system features Tresu's own patented viscosity and flow control, as well as temperature control over the ink as it circulates from ink bucket to anilox roller.  This keeps the ink at constant viscosity to ensure stable ink density on the printed substrate, and constant pressure and flow to stop air mixing with ink in the anilox chamber, in turn preventing blistering and ink starvation. Its airtight environment allows safe handling and storage of solvent inks in environments where solvent evaporations are likely.  

Strokes are counted to determine when fresh ink is pumped into the system, to ensure precise amounts are dispensed to the chamber, leaving minimal residue at the end of the production run. Excess ink can be returned to the bucket for reuse, without wastage. Other features include automatic cleaning after each production run and touch-screen operated real-time viewing. Cleaning cycles are completed in less than a few minutes.  The pump minimizes manual intervention of the ink flow. This is especially beneficial for central impression (CI) presses, where a closed architecture makes ink control and leakage prevention a manually intensive affair during the production run. The F10 iCon Ink Supply System is 1000mm height x 500mm in both width and depth and has a flow range of 5 to 30 litres / minute.

Henrik Kristensen, sales director of Tresu Ancillary, says: "There is a need for improved control of the the ink or coating supply because of faster printing speeds, the trend to shorter production runs and - in the case of central impression machines - the limited possibility of manual intervention production. Our range of chamber doctor blade systems assure quality results at high print speeds and minimise make-ready time. Tresu is constantly working with leading flexo, offset and coating press manufacturers to develop adapted chamber and ink and coating supply solutions that seamlessly fit into any press design."

Tresu has partnerships with several of the world's leading flexo and offset press makers, developing a wide range of auxiliary products for narrow-, mid- and wide-web printing and coating situations. The company has also recently launched Tresu Webshop, so customers can order original ancillary and spare parts as well as consumables directly and at highly competitive prices with authenticity guaranteed.