A light band, slur or register movement that returns at the same position on every print-cylinder revolution is mechanical evidence. Adding impression may hide it for a short run, but extra load can make the mark heavier and move the fault into the plate, tape, gear or bearings. Keep the first samples, calculate the repeat position and inspect the complete cylinder drive before changing several press settings.
Confirm that the fault follows one revolution
Lay several consecutive repeats on a flat table and mark the machine direction, operator side and gear side. Measure the distance between the same visible fault on successive repeats. Compare it with the print-cylinder circumference and the artwork repeat. A mark that returns once per cylinder revolution needs a different investigation from a cross-web band that follows a tension or anilox pattern.
Record the colour, station, cylinder identification, repeat, plate, mounting tape, gear, substrate, press speed and impression setting. Mark the angular position of the fault against a cylinder reference line where the maintained method allows it. Keep an accepted sample from the same job if one is available.
Change only one controlled variable during the first comparison. If the press procedure permits, reduce to setup speed and observe whether the mark stays at the same repeat position. A speed-sensitive change may help maintenance separate a static high spot or mounting issue from a gear or vibration problem, but it does not identify the component by itself.
Rule out the plate and mounting stack first
Inspect the plate around the marked position. Look for a damaged image area, lifted edge, tape overlap, trapped debris, local adhesive residue and any patch where the plate does not sit flat. Check the full cylinder surface under low-angle light. A clean-looking cylinder can still have a raised glue line or small burr beneath the plate.
Confirm the plate revision, plate thickness and mounting-tape product against the approved job record. Check that the tape was applied without overlap and that the leading and trailing edges were handled consistently. If the same fault remains after a controlled remount on a verified clean surface, keep both samples and move the investigation to the cylinder and drive.
Do not add packing or extra local pressure to cancel a high or low area without identifying it. That can produce one acceptable patch while changing dot gain or slur elsewhere around the repeat. The purpose of the remount check is to remove the plate stack as a variable, not to compensate for an unmeasured mechanical fault.
Inspect the gear as a matched drive component
Clean the gear using the approved method, then inspect the full circumference for damaged teeth, wear pattern, debris, corrosion and incorrect seating. Check that the gear specification, pitch, tooth count and mounting arrangement match the press and cylinder drawing. A replacement chosen only because it fits the shaft may not have the required tooth form or accuracy.
Rotometal states that worn or imprecise print-cylinder gears can produce banding and slurring. Its print cylinders can be supplied with standard gears or upgraded hardened and ground gears, depending on the application. That is a specification decision for the cylinder, load, press and production duty, not a reason to replace one gear without checking the mating drive and alignment.
Ask maintenance to inspect backlash, mesh, lubrication and the mating gear using the press manufacturer's method and limits. Rotate the drive safely through a full revolution and record where any tight point, noise or visible tooth damage occurs. If the print fault and a gear condition share the same angular position, preserve that evidence for the cylinder and press suppliers.
Measure journals, bearers and cylinder concentricity
Remove and handle the cylinder according to the press instructions. Clean the journals and bearers without using an abrasive that changes their size or finish. Look for impact marks, raised damage, corrosion and an uneven polished track. Check the press-side bearing and seating surfaces at the same station before declaring the cylinder faulty.
Measure runout and relevant diameters with the maintained instruments, support arrangement and temperature condition. Record the cylinder reference, measuring positions, instrument and result rather than writing runout checked. Rotometal describes concentricity as a core requirement of its print cylinders and lists steel or aluminium bodies with custom journal dimensions and gear options.
Compare the measurements with the cylinder drawing and the press maker's acceptance limits. Do not transfer a tolerance from another cylinder size or press. If a once-per-revolution high point is confirmed, ask whether the cylinder can be inspected, repaired or reground. A visual polish will not correct a dimensional or journal-alignment problem.
Check the station before ordering a replacement cylinder
If the fault follows one cylinder when it is moved to another suitable station, the cylinder assembly becomes a strong suspect. If different cylinders show the same pattern in one station, inspect the press drive, bearings, impression setting and seating at that station. Only make this comparison where the press procedure and cylinder compatibility allow it.
Record whether the band appears in one colour or several colours at the same web position. A shared cross-web movement may belong to web handling or impression rather than one print-cylinder gear. Check the anilox and impression-cylinder condition as part of the station review, but keep the original repeat map so the investigation does not become a general press adjustment exercise.
Before ordering, send the supplier the press model, station, cylinder drawing, repeat, body material, surface, journal and gear details, measured runout, photographs and marked print samples. Include the normal speed, impression setting and whether the fault moved with the cylinder. That information is more useful than ordering another cylinder from diameter and face width alone.
Release the repair at normal production conditions
After the approved repair or replacement, mount the plate using the recorded job standard and run from setup through normal production speed. Take consecutive samples and compare the original fault position, register, tone and impression. Confirm that correcting one mechanical condition has not created a new band or gear mark elsewhere.
Keep the final cylinder drawing, gear specification, inspection report and accepted sample with the maintenance record. Trend similar faults by cylinder and station. If wear returns early, review handling, storage, gear mesh, lubrication and press condition instead of treating the next replacement as an isolated failure.
Royal Coat represents Rotometal rotary tooling across India, Bangladesh, Sri Lanka, Nigeria and Kenya. For a print-cylinder review, send the Royal Coat team the press and station, cylinder identification and drawing, repeat and working width, body and surface, gear details, plate and tape, runout measurements, speed, fault interval, marked samples and photographs of the cylinder, journals and gear.
Questions from production and purchasing teams
What to ask about flexo print cylinder diagnostics
What does a print fault that repeats once per cylinder revolution suggest?
It suggests checking components tied to that revolution, including the plate mount, cylinder surface, gear, journals, bearers and cylinder concentricity. The repeat pattern is evidence, not proof of one failed component.
Can more impression pressure remove the band?
It may change or temporarily hide the mark, but it can add load and create dot gain, slur or wear. Identify the plate-stack or mechanical cause before changing the approved impression setting.
When should the cylinder gear be suspected?
Inspect it when the fault repeats with the cylinder and there is matching tooth damage, wear, debris, incorrect mesh or another measured drive condition. Check the mating gear and station as well.
What information is needed to specify a replacement print cylinder?
Provide the press and station, approved drawing, repeat, working width, body and surface, journals, gear specification, plate and tape, measured runout and marked production samples.
How should the repair be accepted?
Run the approved mounting stack through setup and normal production speed, compare consecutive repeats with the original samples and confirm register, tone and impression across the job.