Using Discharge Inks in Screen Printing: A Guide

Discharge ink printing is a special way to make bright and soft prints on dark clothes. This method removes the clothing’s dye to show the natural fiber color. The result is very soft prints with bright colors that stay vivid for a long time.

Key Takeaways

• Discharge inks remove dyes from garments, allowing pigments to print directly on fibers.
• The process yields vibrant colors and an ultra-soft hand feel.
• Proper ventilation and a conveyor dryer are essential for safe discharge printing.
• Only natural fibers like cotton can be effectively discharged.
• Discharge inks are not recommended for children’s clothing due to formaldehyde residue.

What is Discharge Ink Printing

Discharge ink printing is a special reactive printing way. It uses an ink type that takes out old dyes from fabric. This lets new bright colors get printed on the fabric’s natural fibers. It works great for adding light colors to dark clothes.

How Discharge Ink Works

Discharge inks are thin, water-based inks. They have a discharge ink activator, Zinc-Formaldehyde-Sulfoxylate. When these inks are used on fabric and heated, something unique happens. The formaldehyde in the activator removes the fabric’s dye, making it ready for new colors.

The Chemical Reaction Process

When printed, the clothes go through a hot dryer. At the heat, the formaldehyde in the activator does its work. It removes the fabric’s dye. Then, the sulfur in the discharge agent joins with the formaldehyde. This creates a stable molecule. This stable molecule makes the print last long and stops more chemical reactions.

Importance of Ventilation

Good ventilation is key to working safely with discharge inks. In the curing process, the dryer needs to let out fumes. It’s because the process uses formaldehyde and sulfur. These can be bad if breathed in. So, a proper fume extraction setup keeps the workspace safe. It stops people from breathing in harmful chemicals, putting safety precautions first. Engage with this excellent read.

Prerequisites for Discharge Ink Printing

You need the right tools to get bright and smooth prints with discharge inks. You must have a suitable conveyor dryer, discharge-ready emulsion, and discharge activator.

Conveyor Dryer

A conveyor dryer is key for curing discharge inks. It gives off heat, starting a chemical reaction. This reaction takes the dye out of the fabric. The dryer needs to reach 230°F to 320°F (110°C to 160°C). It must also have good ventilation for the fumes.

Discharge-Ready Emulsion

When you work with discharge inks, you need a special water-resistant emulsion. This type is made to handle the chemicals in discharge inks. Using regular screen printing supplies, emulsions can ruin your prints. It’s best to use something like Baselayr Complete from Avanthi. It keeps the discharge ink from damaging your designs.

Discharge Activator

Discharge inks need a special kick to work, called a discharge activator. This includes Zinc-Formaldehyde-Sulfoxylate for activating the ink. Before you print, mix the activator with the base discharge ink at 6%. Let it sit for 10-30 minutes to dissolve fully. Then, the ink is ready for up to 8 hours, depending on the surroundings.

Choosing the Right Fabric

When doing discharge ink printing, picking the right fabric is key. Natural fiber fabrics like cotton garments and hemp fabric work best. They help get the best printing results with this technique.

100% Natural Fibers

For the best results with discharge inks, choose 100% natural fibers. That means fabrics like cotton and hemp. They take the dye well. But, not all will dye if you mix in synthetic fibers like polyester. This can give your print a cool, vintage look.

Over-Dyed Garments

Some garment makers do over-dyeing. They re-dye shirts, mainly to black, if they didn’t sell in the original color. However, over-dyed shirts might not discharge correctly. This is because the first dye can stop the discharge. So, always do a discharge test first to avoid issues.

Discharge Ink Printing

In screen printing, discharge ink is used in a unique way. It’s applied wet onto wet. This method eliminates the need for flash units or under-bases. Thus, it makes the printing process simpler and faster.

Always keep the discharge ink activated and sealed to avoid drying. This ensures the printing process runs smoothly.

• The discharge ink printing process reaches a chemical reaction point at 230° Fahrenheit.
• Normally, curing the discharge ink happens at 250-260° Fahrenheit.
• On the other hand, water-based inks cure at much higher temperatures, 300-320° Fahrenheit.

When to Use Discharge Ink Printing

Use discharge ink for a soft hand feel on lightweight garment prints. It takes the dyes out of the fabric. This lets the ink go right onto the fibers. The result is a light and super soft print.

Vibrant Colors

Discharge ink makes vibrant prints and bright colors. It swaps the fabric’s original dye with ink pigments. This results in bold, bright hues. They really pop on dark clothes.

Suitable Industries

Discharge ink printing is great for the fashion industry and retail printing. It offers softness and vivid colors. This makes it perfect for making clothes look high-end and appealing to shoppers who love fashion.

The retail and fashion industries like discharge prints for their soft touch and bright designs. It’s also a top choice for athletic wear. The prints are light and comfy, making them perfect for sports clothes.

Considerations for Discharge Ink Printing

Discharge ink printing has great benefits, such as bright colors and a soft feel. But it’s important to remember a few things when using it.

Children’s Clothing

Discharge inks can have too much formaldehyde residue, making them unsafe for children’s apparel. The Consumer Product Safety Improvement Act (CPSIA) doesn’t allow too much formaldehyde in kids’ items. Discharge inks might have more formaldehyde than they should, even though some inks without formaldehyde exist. But, these may not work as well as the ones with formaldehyde.

Sulfur Allergies

Some printing workers might be allergic to sulfur in discharge inks. They might get skin irritation or itch from items not washed after printing. They could even get swollen fingers from touching the ink’s activator. It’s important to know about this and wear the right protective gear. Also, ensure your workspace has good ventilation.

Knowing and acting on these points helps printers use discharge inks safely. This way, they can get the good parts of this ink type without the risks.

Tips for Successful Discharge Ink Printing

To get the best from discharge screen printing, follow key tips. One main tip is selecting the right mesh for discharge inks. The usual range is 43t to 62t (110t to 156t US), but a 55t mesh is best for most printing needs. Keeping your mesh clean and under high tension for quality prints is also vital.

Handling ink the right way is critical for discharge printing. Discharge ink has a short life, about 6-8 hours once activated. So, planning your print work carefully is a must. Using a water spray bottle to dampen screens can prevent ink from drying. It’s also possible to add cross-linkers to the ink for faster drying. But know that this means you must print quickly to avoid problems with the mesh.

At Arizona Screen Printer, we specialize in offering exceptional screen printing and embroidery services at prices that are both competitive and accessible. Catering to clients in Arizona and throughout the United States, we focus on delivering premium screen printing with ease and convenience, ensuring a smooth and satisfying experience for our customers.