Heat transfer printing is becoming a widely popular printing technology solution for many personalization and decorating businesses, hobbyists, and “DIYers”. Similar to other printing technologies such as sublimation, Heat Transfer printing creates the ability to put full-color imagery onto many types of hard and soft products, materials and substrates. Additional benefits to Heat Transfer printing are low equipment maintenance, printing in full color with white, produce imagery on any color product or material, printing on front and back surfaces, and more.
The majority of customers that are new to a printing technology may need to work through a learning curve or two when they first integrate the new technology into their business. Heat Transfer printing is no exception to new learning curves. It is normal for the new Heat Transfer user to experience potential print quality issues or challenges with transferring imagery from the transfer sheet to the final end product. It can be frustrating and costly for the customer to experience these issues repeatedly, despite their best efforts to resolve the issue. In such cases of repeating issues in the Heat Transfer process, often times the environmental conditions in which the Heat Transfer equipment is used will be the root cause of the problems.
Static is one of the most common culprits of problems in the Heat Transfer printing process and is often caused by dry environmental conditions. Static problems are most often seen when printing on the myriad of 2-Step transfer papers for garments and fabrics. Most of these papers are made of a plastic cellophane sheet with a toner-receptive coating on once side. When the humidity of the surrounding environment is too low, static issues will occur more frequently.
Common issues caused by static:
- Ghosting of the printed image on the page
- Pieces of the image repeating across the page
- Toner smearing on the page
- Toner pick-off or failure of toner to fuse to the page
- Paper jamming in printer
Simple ways to mitigate static:
- Test for static on the transfer sheets by holding two sheets of transfer paper vertically and slowly bring them together. The two sheets will try to stick to each other if there is static.
- Remove sheets of transfer paper from the package. Separate the individual sheets from each other. Hold each sheet vertically upright by the top of the sheet and gently shake/fan the sheet several times to help dissipate any static buildup. For best results, gently shake/fan holding each edge of the sheet (four times total) before loading the paper into the printer.
- Lightly and gently rub the surface of the transfer sheet with a cotton ball before loading into the printer to help dissipate static buildup.
- Before running a multi-page print production run, remove several sheets of the transfer paper from the box and separate the pages. Lay the individual pages on a tabletop separately from each other and allow them to sit for 1-2 minutes.
- Load only 6-10 sheets of transfer paper at a time in the printer tray instead of an entire stack of transfer paper. In cases of severe static, loading only 1-3 sheets at a time may be necessary.
- Avoid sliding the transfer sheets across each other, especially from a thick stack of sheets.
- If static issues are observed on the printed sheets, but not obvious on the blank sheets when loading into the printer, print a few sheets of normal copy paper to help clean off and dissipate internal static on the printer rollers. Then continue to print on the transfer sheets.
High and Low Humidity
Another common environmental condition that can cause Heat Transfer printing issues is high and low humidity. For most printer models, the optimal operating humidity range is usually between 40-60% relative humidity. Some printer models may have humidity sensors built into the printer to measure the current humidity level in the environment and automatically adjust the internal printer parameters to help compensate for the current conditions. However, the automatic adjustments the printer may do internally are likely not enough to compensate for elevated high or low of humidity levels. The measured humidity levels may be seen either from the printer menu on the printer’s control panel, or the humidity level may be displayed within the printed configuration page.
Simple ways to manage humidity issues:
- Keep the printer away from open doors or windows.
- Place the printer in an internal room of the building, where the climate control is more stable than a room with outside walls.
- Keep the printer away from direct air currents, such as heating or air conditioning vents or duct work.
- Place a hygrometer or humidity-reading meter near the printer to help monitor the environment around the printer. A meter that also tracks high and low humidity readings is best so that high and low spikes in humidity can be seen.
- When first placing the printer in the operating environment, allow at least 24 hours for the printer to acclimate to the new environment before use.
- Allow new toners and transfer papers to acclimate to the operating environment before use.
- Always store transfer papers closed in the original sealed plastic bag within the original box they came in when not in use.
- Always store unused toners closed in the original sealed plastic bag within the original box they came in.
- In environments of continuous high humidity, consider adding a dehumidifier to help keep the room within the optimal humidity range for the printer and papers.
- In environments of continuous low humidity, consider adding a humidifier to help keep the room within the optimal humidity range for the printer and papers.