How to Select Filtration for Digital Printing Systems?

The use of digital printing systems using inkjet technology has increased significantly in recent years. With increasing reliance on digital printers, print performance and printhead life have become critical. A good printer can reliably produce high-quality output and require minimal maintenance, all of which is possible when appropriate filtering is selected.

Choosing the right ink filter for your system can be difficult. This is where we can help. JOHOPE Technology’s technical experts and sales staff are knowledgeable about the inks, chemistry, applications, and cleanliness required for digital printing. Our team works with you to select filtration, ensuring efficient system performance and superior results.

Why Choose JOHOPE Technology?

Shenzhen JOHOPE Technology Co., Ltd. (hereinafter referred to as JOHOPE Technology) was established in 2003. It is a large-scale wide-format inkjet printer parts manufacturer and supplier integrating R&D, manufacturing, sales, and service. Our main products include ink pumps, sub tanks, ink tubes, filters, solenoid valves, manual valves, liquid level sensors, connectors, print head cleaning cloths and print head cleaning sticks. Our products are widely used in large-format inkjet printing, advertising, printing, chemical experiments, water treatment, and other fields. Through our continuous exploration and efforts, our products have been recognized internationally. In the past few years, our products have been sold to more than 100 countries around the world.

Importance of Choosing a Best Filtration Technology

Filtration is essential for inkjet printing and is a critical fluid delivery system design. This guide contains essential information for selecting the best filtration technology and products. Use it as a resource during system development to ensure optimal printer performance.

Genuine ink is a must for digital printing. It ensures high-quality output and supports optimal printer health. When the printer is in the hands of the customer, filtration of the ink occurs during the ink formulation process and throughout the physical printing process.
Almost all digital printing presses, from large-format printers to common home office equipment, use filters in one form or another. However, larger machines that use bulk, open ink systems require more filtration considerations than smaller printers like the Mutoh and Roland, which use vacuum-sealed ink cartridges.

Digital inkjet filtration is a tricky business, far more so than traditional ink filtration. With very small droplet sizes typically less than 10 picolitres and nozzle holes less than 20 microns, filtration occurs at less than one-tenth the nozzle size and is even smaller when dealing with water-soluble dye-based inks.
The filter captures any particles, dust, or debris that could inadvertently damage the ink. Debris of any kind can severely damage the printer. A partially clogged or completely clogged printhead can cause poor output, damaged substrate, and wasted ink. Filters are generally rated at 5 microns and you need to adhere to this. However, in an emergency, you can use a higher rating, but you cannot use a lower rating as it may damage your printhead.

The starting point for filters is always the ink – is it a dye or a pigment? Dye inks are soluble, so a less soluble filter grade is required. When you’re dealing with pigmented inks, you want a higher rating. It’s all about finding the balance between collecting debris and blocking pigment. If the filter is too fine, it will inhibit the pigment, thereby diluting the final ink concentration and resulting in shortened filter life.

Bulk filters are part of a typical filtration configuration for open ink system printers. These are the most important and best filters and are responsible for capturing most pollutants. Located for easy monitoring and changes, UV curable inks are typically graded at 3-5 microns and other inks at 5-10 microns.

Printer manufacturers recommend replacing filters every six months, consistent with scheduled maintenance procedures, to support printer longevity and consistent high-quality output. If you have a machine that runs 24 hours a day, it will calculate that the filter needs to be changed before this time. You can always replace what needs to happen because your ink flow starts to slow down. Once this happens, it’s too late as blockage can occur very quickly. The best rule of thumb is always prevention is better than cure.

Ink Jet Filtration Products

Multiple Application Capsule

The MAC assembly provides a high level of printhead protection and long service life in ink jet applications.
Features of the MAC filter include the following.

Flexibility: A wide range of filter media and connectors support various printing platforms and requirements.
Robust construction: thick walls and integrally molded connectors increase durability.
Opaque capsule (option): prevents UV light intrusion and ink curing.
Dual filter design (available in pleated models): last chance filter core guarantees maximum cleanliness without
pressure loss.

Acro 25 Filter

The Acro 25 filter is suitable for solvent & UV inkjet printers.

Pall HDC® II polypropylene media: provides excellent dirt-holding capacity and low-pressure drops for long service life.
Opaque polypropylene filter housing: prevents UV light intrusion and ink curing.
Luer lock compatible connectors on inlet and outlet: enable fast filter changes and secure connections.
Low internal hold-up volume: allows for rapid ink system priming

Small Capsule Filter

The SCF assembly is ideal for printers where space is limited and high flow rates are required.

Features of the SCF filter capsule include the following.
Compact capsule: minimizes ink waste and hold-up volume.
High-area pleated construction: accommodates high flow rates and increases service life.
Opaque capsule (option): prevents UV light intrusion and ink curing.
Luer lock compatible connections: facilitate quick and easy filter changes.

Basic Requirements when Evaluating a Filter

When evaluating a filter, consider these basic requirements

• Flow rate. Higher flow rates necessitate larger effective filter areas (EFA).
• Long service life. A service life of at least three months is necessary. The high dirt-holding capacity of depth and pleated-depth filters extends service life. making them the best choices for filtering digital inks.
• Long-term chemical compatibility. The filter should be able to withstand exposure to the ink chemistry over time; the media and capsule compatibility pressure boundary should remain intact.
• Pressure, temperature, and maximum exposure time. A filter capsule is a pressure vessel. it is important to take this into account when considering requirements for pressure, temperature, and maximum exposure time. Pressure and temperature, including any hydraulic or thermal cycling, must be well understood in order to select a filter capsule that is reliable and safe under the specified operating conditions.
• Serviceability. The type and orientation of the connections should facilitate quick filter changes with minimal mess.