Common Wall Printer Problems and How to Fix Them
Table of Contents
In this article, you will learn about more than 10 common wall printer problems and how to fix them, so you will not feel lost when working independently. Whether the issue is related to print quality, ink flow, machine movement, or daily operation, this guide will help you troubleshoot step by step and complete your printing job more smoothly.
Print Quality Issues
Ghosting
Main cause:
Ghosting is usually related to inaccurate bidirectional calibration or an improper distance between the printhead and the wall.
Solution:
Start by recalibrating bidirectional printing to make sure the ink drops align correctly when the printhead moves upward and downward. Then adjust the distance between the printhead and the wall. It should not be too far or too close, but within the recommended working range.
For Friankor machines, the recommended reference distance is about 5cm (1.97 inch) between the black stopper and the wall surface. If the wall has slight unevenness, you can also test with Mode 1 / Mode 3 to find the most stable printing result.
Broken Lines
Main cause:
Broken lines are usually caused by slightly clogged nozzles, dried ink residue on the printhead surface, or air inside the ink path. The printhead may not be completely blocked, but some nozzles cannot spray ink continuously and steadily. This is why broken lines may appear in the nozzle test pattern, and thin white lines may also appear in the actual printed image.
Solution:
Start with ink extraction to make sure ink can flow properly into the printhead channel. If broken lines still remain after ink extraction, perform printhead cleaning and test again.
To learn more about Friankor’s automatic ink extraction system, you can refer to this article: Say Goodbye to Syringes: Friankor’s Wall Printer Auto Ink Extraction System
The video below also demonstrates the actual operation process of automatic ink extraction and printhead cleaning, which may help if you are not sure how to perform the steps correctly:
Banding
Main cause:
Banding should first be identified by direction. Horizontal banding is often related to incomplete ink output or an unstable ink supply system. Vertical banding is more often caused by unstable machine movement, such as uneven rails, uneven ground, or slight vibration during printing.
Solution:
If the banding is horizontal, perform ink extraction or printhead cleaning depending on the nozzle test result. If the banding is vertical, focus on checking whether the rail connections are secure, whether there is any debris on the rails, and whether the machine moves smoothly during printing.
Do not clean the printhead immediately every time you see banding. Identifying the direction of the stripes first will make troubleshooting much more accurate.
Missing Color
Main cause:
Missing color is usually related to an abnormal color channel. The problem may come from insufficient ink in that color, a clogged nozzle, poor ink supply, or an abnormal printhead channel. If one color is missing from the image, the issue is usually more obvious than normal broken lines.
Solution:
Print a nozzle test pattern first to confirm which color channel is missing. Then check the ink level and ink tube condition for that color. If it is only a minor clog, ink extraction or cleaning may restore the output. If the same color remains abnormal for a long time, contact professional after-sales support to check whether it involves other hardware issues.
Blurry Image
Main cause:
A blurry printed image is usually related to the source file quality. Low image resolution, excessive enlargement, or mismatched printhead DPI and feathering settings can all make the final wall print look soft or unclear.
Solution:
For regular projects, the image resolution is generally recommended to be at least 720×900 or 720×1200. For large-format projects, a higher-resolution image or vector file is recommended. If the original image quality is not good enough, you can use tools such as Upscayl to improve clarity.
If you are not sure how to check image size, adjust resolution, or prepare print files in Photoshop, you can watch the tutorial video below and follow the steps before importing the file into the printing software.
Print clarity can also be affected by Pass and Feathering settings. To learn how to balance print sharpness and efficiency, you can refer to this guide: Wall Printer Settings Guide: Optimal Pass & Feathering for 5 Scenarios
Jagged Edges
Main cause:
Jagged edges may be caused by uneven column connection points or rail joints. The wall printer column is connected through pins. Under normal conditions, when the pins stay straight, the column height remains stable, and lifting and printing can run properly.
However, if the pin is slightly bent or deformed, it may create a height difference at the column connection. This can cause tiny movement deviations during lifting or printing, resulting in jagged edges. Rail joints work in a similar way. If the rail connection is not smooth, the horizontal movement of the machine can also be affected.
Solution:
Run your hand along the column connection and rail joint areas to check whether there are bumps, bends, uneven joints, misalignment, or loose connections. Refix the connection points and make sure both the vertical lifting and horizontal movement remain stable before continuing to print.
Ink Flow and Adhesion Issues
Blistering or Local Peeling
Main cause:
This problem often appears on smooth materials such as glass and ceramic tile. These surfaces are dense and have weak absorption. If the surface is not cleaned properly before printing, or if no coating is applied, UV ink may not adhere firmly. When the ink layer does not dry or stabilize properly, blistering or peeling may appear later.
Solution:
Clean the material surface before printing and remove dust, oil, or other contaminants. Apply the proper coating solution, wait until the surface is dry, and then start printing
Ink Dripping
Main cause:
Ink dripping usually means the ink has not cured in time, or the UV lamp surface is blocked by ink, dust, or other debris. The printing environment can also affect ink behavior.
Solution:
During printing, repeatedly confirm that the UV lamp is working properly. Friankor recommends printing in an environment of 15°C–35°C, with humidity kept around 45%–70% RH.
Ink Scattering
Main cause:
Ink scattering happens when the ink droplets drift or spread before reaching the wall, usually because the distance between the printhead and the wall is too far. This makes the edges of the image look scattered and less focused. In outdoor environments, strong wind can make the ink droplets drift even more and cause visible scattering.
Solution:
Adjust the distance between the printhead and the wall according to the waveform and actual printing effect. Make sure Mode 3 automatic sensing is enabled so the machine can adjust the distance according to the wall surface. If you are printing outdoors, adjust the print speed, pass, and ink output as needed, and use wind protection when necessary.
No Ink Output
Main cause:
No ink output can be caused by several factors, including insufficient ink, incomplete ink extraction, air inside the ink path, loose printhead cables, or printhead damage. This issue should not be judged from only one angle. It needs to be checked step by step from ink, ink path, cables, and printhead condition.
Solution:
First, check whether there is enough ink. Then confirm whether ink extraction is working properly. If ink extraction is normal but ink still does not come out, check the ink tube, ink path, and printhead cable connection. If the issue cannot be solved after basic checks, do not force repeated cleaning. Contact after-sales engineers for further diagnosis of the printhead and circuit condition.
Mechanical and Movement Issues
Printhead Clogging
Main cause:
Printhead clogging is usually related to insufficient daily maintenance. If the machine is not used for a long time, or if the printhead is not cleaned, sealed, or maintained properly after shutdown, ink residue may clog the printhead and cause poor ink output, broken lines, or missing colors.
Solution:
Start with ink extraction, then perform printhead cleaning if needed. During daily use, regularly maintain and protect the printhead to prevent ink from staying too long on the printhead surface or inside the internal channel.
For a complete maintenance method, you can refer to this guide: How to Maintain a UV Vertical Wall Printer.
Printhead Shaking During Lifting or Lowering
Main cause:
Printhead shaking during lifting or lowering is usually related to overly sensitive Mode 3 automatic sensing, unstable column connections, or the overall stability of the machine structure.
Solution:
Lower the Mode 3 sensing speed slightly to make the printhead move more smoothly during automatic adjustment. Also check whether the column connection is properly locked. If the wall is relatively flat, you can also switch to Mode 1 fixed mode for testing.
For projects that require higher on-site stability, a machine with a more mature structure, such as the Friankor MK02, can help reduce unnecessary vibration during lifting and long-time printing.
Printhead Touching the Wall During Printing
Main cause:
This usually happens when sensing mode is not enabled, or when there are raised areas on the wall. Some problems may not be obvious to the eye, but you can feel joints or height differences by touching the surface. If the wall distance changes and the machine does not sense and adjust in time, collision may occur.
Solution:
Before printing, do not rely only on visual inspection. Touch the printing area by hand to check whether there are hidden bumps, depressions, joints, or uneven areas. If the wall is not flat enough, enable Mode 3 automatic sensing so the machine can adjust according to the wall distance.
To learn how to evaluate the wall surface, flatness, and potential risks before printing, refer to this guide: Wall Printing Business Guide: How to Assess Any Substrate & Prevent Costly Rework.
Quick Wall Printer Troubleshooting Checklist
Quick Wall Printer Troubleshooting Checklist
| Symptom | Main Cause | First Action |
| Ghosting | Calibration or wall distance issue | Recheck bidirectional calibration and printhead distance |
| Broken lines | Nozzle clogging or air in ink path | Run ink extraction and nozzle cleaning |
| Banding | Nozzle issue or unstable movement | Identify stripe direction first |
| Missing color | One color channel abnormal | Check ink level, ink tube, and nozzle test |
| Blurry image | Low-resolution source file | Check file size, DPI, and Pass / Feathering |
| Jagged edges | Column pin or rail joint issue | Check column pins and rail connections |
| Poor adhesion | Smooth surface without treatment | Clean surface and apply proper coating |
| Ink dripping | UV curing or environment issue | Check UV lamp, humidity, temperature, and ink amount |
| Ink scattering | Printhead too far from wall | Adjust distance and enable Mode 3 |
| No ink output | Ink path or printhead issue | Check ink, extraction, cable, and printhead |
| Printhead shaking | Mode 3 too sensitive or structure unstable | Lower sensing speed and check stability |
| Head touching wall | Uneven wall or no sensing mode | Check wall by sight and touch before printing |
Other Issues
When browsing forums and community discussions, I noticed several interesting and useful cases from real wall printing projects and customer feedback. By looking at discussions on Reddit and printerfamily, we can see how operators deal with different environments, use cases, and practical problems.
Misalignment or Wrong Print Start Point
Cross cursor calibration is very important in this step. Machine repositioning, printhead-to-wall distance, and machine parallelism with the wall can all affect the final starting point.
For example, when using the black stopper as a reference and keeping it about 5cm (1.97 inch) from the printing surface, the cross cursor may shift slightly after the machine is moved. Even a small tilt angle can affect the final print. This shift may not look obvious at first, but it can be magnified during printing, causing an inaccurate start point, tilted image, or poor alignment in multi-section printing.
Therefore, every time the machine is moved, the wall distance is adjusted, or the file is reset, the cross cursor position should be checked again.
Does Ink Smell Mean It Is Toxic?
In some indoor projects, customers may smell a slight ink odor when they first see a wall printer working on-site. They may immediately ask, “Is this ink safe?”
In fact, odor does not automatically mean the ink is harmful. Many UV inks may have a slight smell during printing, but after UV curing, the ink quickly stabilizes on the wall surface.
What really matters is ink quality, proper curing, and good ventilation. For indoor spaces such as schools, children’s rooms, offices, and restaurants, we recommend using stable original UV ink and keeping the work area ventilated during printing.
For a more detailed explanation, you can read this article: Is Wall Printer Ink Eco-Friendly?
Conclusion
Let’s quickly summarize the key points to keep in mind when using the wall printer.
Skillful operation is essential for producing high-quality prints. If you want to reduce operation mistakes, you can follow the video below and learn the full workflow step by step.
The last and most important point is to choose a reliable manufacturer. Once you purchase a wall printer, you will need support for debugging, maintenance, software operation, and troubleshooting. We have also seen customers contact us through WhatsApp after buying wall printers from other brands because they could not get timely technical guidance and eventually came to Friankor for help.
This is why after-sales support and warranty protection matter so much. Before buying a machine, make sure the manufacturer can provide timely, reliable, and long-term technical support. For example, Friankor now provides lifetime technical support, and customers can also enjoy a two-year free warranty service for more confidence in long-term use.
👇To learn more about Friankor wall printers, please fill out the form below and contact our team.
Mode Note
In this article, Mode 1 refers to fixed mode, which is more suitable for relatively flat walls where the distance between the printhead and the wall does not change much.
Mode 3 refers to automatic sensing mode, which is more suitable for walls with slight unevenness where the machine needs to automatically adjust the printhead distance.
Contact Us
FIll out the form below and we will cantact you as soon as possible
