The short version
- 01Decide first whether the lines are lighter or darker than the page.
- 02Print a nozzle check and clean only if it shows streaks or missing lines.
- 03Compare nozzle checks between cycles and stop after two or three without change.
- 04Align the print head if banding persists once the nozzle check is clean.
- 05Rest an unused printer overnight before reaching for Power Cleaning.
- 06Measure the spacing of dark repeating marks — a regular interval means a roller.
Start here
Are the lines lighter than the page, or darker?
That one distinction splits the problem before you spend any ink. Light or white lines through the print mean something is missing — clogged nozzles on an inkjet, or toner not reaching the page on a laser — and the fix is a nozzle check and a head clean. Dark lines, smears or marks that repeat at regular intervals mean something is adding to the page, which is a roller, a drum or contamination, and cleaning the print head will do nothing at all except waste ink.
Applies to: Inkjet printers from Epson, Canon, HP and Brother, and laser printers from the same. The nozzle check and head cleaning steps are inkjet-specific; the drum, roller and repeating-mark guidance in section 4 applies to lasers.
What do the lines look like?
Lines in a printout are two opposite faults with one description. Missing output and added output need entirely different work, and running head cleaning on a printer that is depositing marks is the most common wasted effort in this whole area — each cycle consumes ink and moves you no closer. Look at the page in good light, decide whether the lines are lighter or darker than their surroundings, and follow that branch.
White or pale streaks through the print
Does the nozzle check show gaps?
Run a nozzle checkLines persist after cleaning
Has the print head been aligned?
Align the headDark lines, smears or repeating marks
Do the marks repeat at a regular spacing?
Check drum and rollersIt has been unused for months
Is the ink dried in the nozzles?
Deep clean carefully1. Light lines: run the nozzle check and read it
For pale or missing lines on an inkjet, the nozzle check is both the diagnosis and the decision. Print one from the printer's own maintenance menu and look at the pattern rather than at your document. Epson's instruction is direct: clean the print head if horizontal white streaks are present in the printed nozzle check pattern, or if lines are missing from it. That is the test that tells you cleaning will actually help.
The pattern also tells you which colour is affected, which is worth noting before you start. A single colour missing points at one channel — often the one you use least, since it is the one that sits longest between uses. Every colour showing gaps at once usually means the printer has been idle rather than that four channels failed independently.
Then clean, and stop when the evidence says to. Cleaning unclogs the nozzles and restores the print head, but Epson is equally clear that cleaning the print head consumes ink, so clean only when necessary. Run a cleaning cycle, print another nozzle check, and compare. Improvement between cycles means keep going; no change across two or three means cleaning is not the answer and section 5 applies.
Compare nozzle checks rather than documents. A photograph looks different for a dozen reasons; the nozzle check pattern is the same every time, so a change in it is real evidence.
2. Lines that survive cleaning: alignment
If banding persists once the nozzle check is clean, the nozzles are firing and the problem is where they are firing. Epson's guidance covers this case specifically: if you continue to see horizontal or vertical bands or streaks in your printouts after cleaning and aligning the print head, you can finely tune the horizontal or vertical alignment in the Maintenance menu.
Run the standard print head alignment first — it prints a set of patterns and asks you to choose the best one, and it corrects the ordinary drift that develops as a printer ages. Only if banding remains after that is the fine-tuning worth reaching for, and it is a separate option rather than a repeat of the same routine.
Alignment problems have a recognisable signature: the print is complete, with nothing obviously missing, but edges look slightly doubled or text looks fuzzy at close range, and banding appears as regular light bands rather than hard white gaps. If your lines are hard-edged and completely white, that is a nozzle problem rather than an alignment one, and going back to section 1 is the better use of your time.
3. A printer that has sat unused
Ink dries in nozzles when a printer is idle, and a machine that has not been used for months is the classic case for banding across every colour at once. Ordinary cleaning may not shift it, and repeating ordinary cycles indefinitely is how people empty a set of cartridges without fixing anything.
Epson provides a stronger routine for exactly this and attaches a clear warning to it: if you have not used the product for a long time, run the Power Cleaning utility — but Power Cleaning consumes a lot of ink, so run it only if you cannot improve print quality by cleaning the print head first. Treat it as a deliberate escalation with a real cost, not a bigger button.
The step that costs nothing is patience. Leaving the printer switched off overnight lets residual solvent soften dried ink, and a head that resisted several cleaning cycles often clears on the first cycle the next day. It is the same principle as the overnight rest for blank pages, and it is worth trying before a Power Cleaning rather than after.
Normal clogging
Standard head cleaning, then a nozzle check to compare. Stop after two or three cycles without improvement.
Long-unused printer
Rest it overnight first. Then Power Cleaning if needed — Epson warns it consumes a lot of ink.
4. Dark lines and repeating marks
Dark lines are the opposite fault and need the opposite thinking: something is putting toner or ink on the page where it should not be. No amount of head cleaning addresses this, and on a laser printer there is no print head to clean in the first place.
The most useful clue is spacing. Marks that repeat down the page at a consistent interval come from something round — a drum or a roller — and the interval corresponds to its circumference. A defect on a drum leaves a mark once per rotation, so evenly spaced spots or bars are close to a positive identification. Measure the gap between two marks; a consistent measurement points at a rotating part, and an inconsistent one does not.
On a laser printer, a vertical dark line down the length of every page usually means a scratched or contaminated drum, or toner that has escaped from the cartridge. Removing the toner and drum unit and inspecting them in good light is the next step, along with checking for loose toner inside the printer. Brother publishes drum cleaning guidance, and the rule that matters is never to touch the photosensitive drum surface with anything sharp.
Dark smearing that appears on the back of pages rather than the front is loose toner inside the paper path rather than a drum defect. That is a cleaning job, not a replacement one.
5. Paper, settings and the things that imitate a fault
Before concluding a printer needs parts, rule out the page itself. Paper that is damp, textured, or the wrong weight for the setting produces uneven ink coverage that reads as banding. Print the same document on a fresh sheet from a newly opened ream as a control — if it comes out clean, the paper was the variable.
Check that the media type in the driver matches what is loaded. A printer told it is printing on plain paper while loaded with photo paper lays down the wrong amount of ink, and the result is banding that no amount of maintenance will remove. Draft or economy modes do the same deliberately, and one left enabled from a previous job is a common cause of output that suddenly looks poor.
Cartridge state matters too. A cartridge low on one colour bands before it fails outright, and a third-party or refilled cartridge that does not maintain pressure correctly produces intermittent gaps. If banding tracks one colour and that cartridge is low or aftermarket, fitting a known-good original is a fast way to settle whether the printer or the cartridge is at fault.
6. When to stop cleaning, and what to tell support
There is a real endpoint and it is worth respecting, because the failure mode here is spending more on ink than the printer is worth. A head that has not improved across two or three cleaning cycles, an overnight rest and a Power Cleaning has a hard clog or a failed head rather than a soft blockage. On most consumer inkjets, replacement is the honest recommendation at that point.
Prevention genuinely works for this specific fault. Nozzles clog because ink dries in them, and ink dries when a printer sits idle — so printing a single colour page every week or two keeps ink moving through every channel and prevents the situation entirely. It matters far more on an occasionally used printer than on one used daily.
When you contact support, lead with the nozzle check and the direction of the lines. Say whether the lines are lighter or darker than the page, what the nozzle check pattern showed and which colours, how many cleaning cycles you ran and whether the pattern improved between them, whether the marks repeat at a regular spacing, and whether a fresh sheet from a new ream printed the same. Those five answers separate a clog from an alignment problem from a drum or roller from paper.
Frequently asked questions
Why is my printer printing lines through everything?
Look at whether the lines are lighter or darker than the page — that splits the problem. Light or white lines mean something is missing, which is clogged nozzles on an inkjet, and a nozzle check plus head cleaning is the fix. Dark lines or repeating marks mean something is being added to the page, which is a roller or drum, and head cleaning will only waste ink.
How do I know if cleaning the print head will help?
Run a nozzle check first and read the pattern. Epson's guidance is to clean the print head if horizontal white streaks are present in the nozzle check pattern, or if lines are missing from it. If the pattern is complete and your document still bands, cleaning won't help — that's an alignment problem, or paper, or settings.
How many times should I clean the print head?
Print a nozzle check between cycles and compare the patterns, not your documents. Improvement between cycles means continue; no change across two or three means cleaning isn't the answer. Cleaning consumes ink every time, and Epson's guidance is to clean only when necessary — this is where people empty cartridges without fixing anything.
What is Power Cleaning and when should I use it?
It's Epson's stronger routine for a printer that has been unused for a long time. Their warning is explicit: it consumes a lot of ink, so run it only if you can't improve print quality with ordinary head cleaning first. Before reaching for it, leave the printer off overnight — dried ink softens, and a head that resisted several cycles often clears the next morning.
Why does my laser printer put a dark line down every page?
Usually a scratched or contaminated drum, or toner that has escaped inside the printer. Measure the spacing between repeating marks: a consistent interval points at something round, because a drum defect leaves a mark once per rotation. Remove the toner and drum unit and inspect them in good light, and never touch the photosensitive drum surface with anything sharp.
Can paper cause lines in my printouts?
Yes, and it's worth ruling out before buying parts. Damp, textured or wrong-weight paper gives uneven coverage that reads as banding. Print the same document on a fresh sheet from a newly opened ream as a control. Also check the media type in the driver matches what's loaded — a printer told it's on plain paper while loaded with photo paper lays down the wrong amount of ink.
Sources and review notes
Checked on . Compiled by Glitchary from Epson and Canon support documentation. Maintenance menu names, nozzle check patterns and cleaning routines vary by printer model and manufacturer — check the manual for yours, and note that Power Cleaning is Epson’s name for its deep clean. The drum and roller guidance for laser printers reflects general practice rather than a single vendor’s documentation, and internal repairs should go to a qualified technician. Glitchary is independent of Epson, Canon and the other manufacturers named here.