News
Why do white edges appear on DTF prints?
2025-08-22
DTF printers are specifically designed for printing patterns on garments and are recognized by the industry for their clear, realistic pattern transfers. A single machine can perform everything from pattern printing, dusting, shaking, and drying, easily achieving photo-like results.
DTF printers are precision instruments, so minor issues are inevitable during use, such as white edges on printed products. What causes this? How can we resolve it?
There are several possible reasons why white edges appear in DTF printing:
1. Equipment failure
Clogged or damaged printhead: This is one of the most common causes, especially affecting the white ink channel. White ink pigment particles are heavier and more likely to settle and clog the printhead, so special attention needs to be paid to maintenance and circulation.
Partial blockage: If the white ink nozzles responsible for the edge of the pattern are partially blocked, insufficient or discontinuous white ink will be sprayed in that area. During powder spreading, the powder will not adhere effectively to these areas, resulting in white edges after curing.
Complete blockage/damage: If the nozzle does not work at all, there will be no white ink at the corresponding position, and a white edge will inevitably form.
Improper print head height: The print head is too high from the film surface, and the flight trajectory of the ink droplets is offset, resulting in inaccurate landing points (especially the edges), and the white ink cannot accurately cover the predetermined edge position.
White ink circulation system failure: DTF printers typically have a white ink circulation system to prevent sedimentation. If this system fails, the white ink pigment will settle, resulting in uneven concentration and insufficient covering power. The edges of the ink are particularly prone to showing the background color (film or incompletely covered color), forming white edges.
Ink supply system problems: ink tube blockage, ink bag air intake, unstable ink pump pressure, etc. may cause discontinuous or insufficient white ink supply, affecting edge coverage.
Curing equipment problem (indirect): Although curing itself does not directly produce white edges, if the curing temperature or time is insufficient, the powder fails to completely melt and level, and the edge powder may shrink or fail to completely cover the edge of the white ink layer, which may also present a similar white edge effect.
2. Violations:
Using low-resolution design files: The resolution of the design files provided by the customer or used by the operator is too low. When printed, the edges of the image will appear jagged (pixelated). The printer has difficulty accurately and evenly laying down white ink along these rough, stepped edges, resulting in incomplete edge coverage and a white edge after powder coating.
Improper powder spreading: Insufficient powder spreading, uneven powder spreading (such as less powder in the edge area), or recovery and curing of powder too early/too late after spreading may result in insufficient or loose powder coverage at the edge of the pattern.
Premature powder removal/under-curing: Moving or handling the film before the powder has fully melted and leveled may cause edge powder shifting or incomplete coverage.
Using incompatible consumables: To reduce costs, non-genuine or uncertified white ink, powder, pre-treatment fluid, or film is used. The physical and chemical properties of these consumables (such as viscosity, particle size, activation properties, and surface tension) may not match the printer and process, resulting in poor white ink spreading and powder adhesion, especially edge issues.
3. Pollution:
Print platform contamination: Dust, debris, dried ink, or powder particles accumulate on the print platform. When laying down the film, these contaminants can cause it to bulge in certain areas, preventing it from completely flattening against the platform. During inkjet printing, the white ink beneath the bulge cannot be accurately jetted, or the ink droplets are blocked, resulting in missing white ink in that area (often near the edges), creating white edges or defects.
Printhead surface contamination: The printhead surface (especially the nozzle plate) is contaminated with ink, dust, or powder. This can interfere with the proper formation and direction of ink droplets. This can especially affect precise white edge coverage, causing droplets to skew, be missing, or form satellite drops, resulting in white lines along the edges.
Powder contamination/moisture: Powder can become contaminated with impurities, clump, or absorb moisture from the air. Moist or clumped powders can become damp and have poor flowability, making even coverage difficult during sprinkling. Edges are particularly prone to insufficient coverage or non-adhesion, resulting in white edges. Impurities can also prevent powder from adhering.
4. Static electricity:
Film static electricity: PET film is very easy to generate and accumulate static charges during the production and transportation process.
Static electricity will: Attract dust: Make the film surface (especially the edges) more likely to absorb dust in the environment, forming contamination points, and hindering white ink adhesion or powder coverage.
Powder repulsion/impact on powder spreading: Static charge may interfere with the charged state of the powder (usually powder spreading equipment uses static electricity to assist powder adsorption), causing powder to be repelled or unevenly distributed in the edge area, resulting in poor coverage.
Affecting the landing point of ink droplets: Strong electrostatic fields may even affect the flight trajectory of tiny ink droplets, causing them to deviate from the target position.
Color and white printhead misalignment: DTF printers typically have separate color and white printhead groups. If these two groups are physically offset (not precisely aligned) during installation or use, the white base and color pattern will not be perfectly aligned in space.
Incomplete edge coverage: The most common misalignment occurs when the white plate fails to fully "underline" the color pattern, especially at one edge of the pattern, where the white layer lies further inward than the color layer. This causes the edge of the color pattern to "float" directly on the film, where the white ink is absent. During powdering, this area lacks adhesion, resulting in a clear white edge outside the color pattern after curing. This is a typical and direct cause of white edge issues.
5.Semi-transparent pixels at the edge of the graphic:
There's a problem with the pattern itself: The product image itself has white edges, but because they're hidden deep within the image, they're not easily visible. The first thing to do when this happens is to modify the pattern. Use Photoshop to remove the white edges.
In summary:
White edge issues in DTF printing are the result of a multifaceted interaction. They may stem from equipment status (printers, ink supply, platform), operational specifications (file handling, pretreatment, powder spreading, curing), environmental control (contamination, static electricity), consumables quality, process limits (fine design), equipment calibration (printer alignment), and the characteristics of the design file itself (resolution, edge pixelation). Resolving white edge issues requires a systematic investigation of all these aspects, from equipment maintenance, standardized operating procedures, environmental control, the use of qualified consumables, optimized design files, to precise equipment calibration. During diagnosis, observing the specific appearance of the white edge (whether it is regular, which side it appears on, and whether it is accompanied by other defects) can help narrow the scope of investigation.
If you are using a Heyme machine, please contact our dedicated engineers when you encounter a problem. They will troubleshoot the problem for you as soon as possible and help you solve it.
DTF printers are precision instruments, so minor issues are inevitable during use, such as white edges on printed products. What causes this? How can we resolve it?
There are several possible reasons why white edges appear in DTF printing:
1. Equipment failure
Clogged or damaged printhead: This is one of the most common causes, especially affecting the white ink channel. White ink pigment particles are heavier and more likely to settle and clog the printhead, so special attention needs to be paid to maintenance and circulation.
Partial blockage: If the white ink nozzles responsible for the edge of the pattern are partially blocked, insufficient or discontinuous white ink will be sprayed in that area. During powder spreading, the powder will not adhere effectively to these areas, resulting in white edges after curing.
Complete blockage/damage: If the nozzle does not work at all, there will be no white ink at the corresponding position, and a white edge will inevitably form.
Improper print head height: The print head is too high from the film surface, and the flight trajectory of the ink droplets is offset, resulting in inaccurate landing points (especially the edges), and the white ink cannot accurately cover the predetermined edge position.
White ink circulation system failure: DTF printers typically have a white ink circulation system to prevent sedimentation. If this system fails, the white ink pigment will settle, resulting in uneven concentration and insufficient covering power. The edges of the ink are particularly prone to showing the background color (film or incompletely covered color), forming white edges.
Ink supply system problems: ink tube blockage, ink bag air intake, unstable ink pump pressure, etc. may cause discontinuous or insufficient white ink supply, affecting edge coverage.
Curing equipment problem (indirect): Although curing itself does not directly produce white edges, if the curing temperature or time is insufficient, the powder fails to completely melt and level, and the edge powder may shrink or fail to completely cover the edge of the white ink layer, which may also present a similar white edge effect.
2. Violations:
Using low-resolution design files: The resolution of the design files provided by the customer or used by the operator is too low. When printed, the edges of the image will appear jagged (pixelated). The printer has difficulty accurately and evenly laying down white ink along these rough, stepped edges, resulting in incomplete edge coverage and a white edge after powder coating.
Improper powder spreading: Insufficient powder spreading, uneven powder spreading (such as less powder in the edge area), or recovery and curing of powder too early/too late after spreading may result in insufficient or loose powder coverage at the edge of the pattern.
Premature powder removal/under-curing: Moving or handling the film before the powder has fully melted and leveled may cause edge powder shifting or incomplete coverage.
Using incompatible consumables: To reduce costs, non-genuine or uncertified white ink, powder, pre-treatment fluid, or film is used. The physical and chemical properties of these consumables (such as viscosity, particle size, activation properties, and surface tension) may not match the printer and process, resulting in poor white ink spreading and powder adhesion, especially edge issues.
3. Pollution:
Print platform contamination: Dust, debris, dried ink, or powder particles accumulate on the print platform. When laying down the film, these contaminants can cause it to bulge in certain areas, preventing it from completely flattening against the platform. During inkjet printing, the white ink beneath the bulge cannot be accurately jetted, or the ink droplets are blocked, resulting in missing white ink in that area (often near the edges), creating white edges or defects.
Printhead surface contamination: The printhead surface (especially the nozzle plate) is contaminated with ink, dust, or powder. This can interfere with the proper formation and direction of ink droplets. This can especially affect precise white edge coverage, causing droplets to skew, be missing, or form satellite drops, resulting in white lines along the edges.
Powder contamination/moisture: Powder can become contaminated with impurities, clump, or absorb moisture from the air. Moist or clumped powders can become damp and have poor flowability, making even coverage difficult during sprinkling. Edges are particularly prone to insufficient coverage or non-adhesion, resulting in white edges. Impurities can also prevent powder from adhering.
4. Static electricity:
Film static electricity: PET film is very easy to generate and accumulate static charges during the production and transportation process.
Static electricity will: Attract dust: Make the film surface (especially the edges) more likely to absorb dust in the environment, forming contamination points, and hindering white ink adhesion or powder coverage.
Powder repulsion/impact on powder spreading: Static charge may interfere with the charged state of the powder (usually powder spreading equipment uses static electricity to assist powder adsorption), causing powder to be repelled or unevenly distributed in the edge area, resulting in poor coverage.
Affecting the landing point of ink droplets: Strong electrostatic fields may even affect the flight trajectory of tiny ink droplets, causing them to deviate from the target position.
Color and white printhead misalignment: DTF printers typically have separate color and white printhead groups. If these two groups are physically offset (not precisely aligned) during installation or use, the white base and color pattern will not be perfectly aligned in space.
Incomplete edge coverage: The most common misalignment occurs when the white plate fails to fully "underline" the color pattern, especially at one edge of the pattern, where the white layer lies further inward than the color layer. This causes the edge of the color pattern to "float" directly on the film, where the white ink is absent. During powdering, this area lacks adhesion, resulting in a clear white edge outside the color pattern after curing. This is a typical and direct cause of white edge issues.
5.Semi-transparent pixels at the edge of the graphic:
There's a problem with the pattern itself: The product image itself has white edges, but because they're hidden deep within the image, they're not easily visible. The first thing to do when this happens is to modify the pattern. Use Photoshop to remove the white edges.
In summary:
White edge issues in DTF printing are the result of a multifaceted interaction. They may stem from equipment status (printers, ink supply, platform), operational specifications (file handling, pretreatment, powder spreading, curing), environmental control (contamination, static electricity), consumables quality, process limits (fine design), equipment calibration (printer alignment), and the characteristics of the design file itself (resolution, edge pixelation). Resolving white edge issues requires a systematic investigation of all these aspects, from equipment maintenance, standardized operating procedures, environmental control, the use of qualified consumables, optimized design files, to precise equipment calibration. During diagnosis, observing the specific appearance of the white edge (whether it is regular, which side it appears on, and whether it is accompanied by other defects) can help narrow the scope of investigation.
If you are using a Heyme machine, please contact our dedicated engineers when you encounter a problem. They will troubleshoot the problem for you as soon as possible and help you solve it.