Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
A laser or LED-page printer builds an image with three parts working together: a toner cartridge, an imaging or drum unit, and a fuser. Any one of the three can fail on its own, and each failure looks different on the page. Print that is light or grey all over usually points at the toner cartridge or the imaging unit. A line or a streak that repeats in the same place on every page usually points at the imaging or drum unit. Marks that repeat down one page at an even spacing point at whichever part turns once per that spacing — the manufacturer's own chart names it, and this page will not guess. Toner that smears or rubs off after the page is printed points at the fuser, the part that uses heat and pressure to bond toner to paper.
This page does not replace any part. It walks through what you can observe from outside the printer — the printed page, the toner level display, a measured spacing — and tells you which part the evidence points at, so that the part you buy is the part that is actually worn. People search for this under many names: a laser printer with faded print, toner that smears when you touch it, a vertical line on every printout, repeating marks every few inches, or a printer that streaks a black line down the page. All five are covered here.
Necessary equipment
| Item | Note |
|---|---|
| The printed page that shows the fault | This page is the sample every check in this record compares against. |
| Plain white paper | Letter or A4 paper is satisfactory for a new test print. |
| A ruler or a tape measure optional | A ruler measures the distance between two marks that repeat. |
Print a sample and examine it
Estimated under a minute to 2 min
- Print a plain document with full black text.<1mReport a problem with step 1, Print a sample and examine it
- Your printer documentation gives the control for a built-in test page.
- Look at the printed page in good light.<1mReport a problem with step 2, Print a sample and examine it
- Weak light can hide a faint mark.
Print that is light or grey over the whole page
Estimated 3 min to 4 min
- If the print is light or grey over the whole page, do the checks in this section.<1mReport a problem with step 1, Print that is light or grey over the whole page
- Find the print density control in the printer driver or on the display.<1mReport a problem with step 2, Print that is light or grey over the whole page
- Brother instructs owners to raise this control before any other check for light print.
- Increase the print density setting by a small amount.<1mReport a problem with step 3, Print that is light or grey over the whole page
- Print the page again and compare it with the first print.<1mReport a problem with step 4, Print that is light or grey over the whole page
- If the new page is not light, the density setting was the cause.<1mReport a problem with step 5, Print that is light or grey over the whole page
- If the new page is still light, find the toner level display.<1mReport a problem with step 6, Print that is light or grey over the whole page
- If the toner level display reads low, the toner cartridge is the likely cause.<1mReport a problem with step 7, Print that is light or grey over the whole page
- Canon documentation names deteriorated toner cartridge parts as a cause of faded printouts.
- If the toner level display reads normal or high, the imaging or drum unit is the likely cause.<1mReport a problem with step 8, Print that is light or grey over the whole page
- A normal toner reading with a light page points away from the toner cartridge.
A line or a streak that repeats in the same place
Estimated under a minute
- If a line or a streak repeats in the same place on every page, do the checks in this section.<1mReport a problem with step 1, A line or a streak that repeats in the same place
- Find the toner level display.<1mReport a problem with step 2, A line or a streak that repeats in the same place
- If the toner level display reads low, the toner cartridge is a likely cause.<1mReport a problem with step 3, A line or a streak that repeats in the same place
- If the toner level display reads normal, the imaging or drum unit is a likely cause.<1mReport a problem with step 4, A line or a streak that repeats in the same place
- Brother documentation names a part inside the drum unit as a cause of one repeated stripe.
- Canon documentation names a dirty fuser area as a separate cause of streaks.
Marks that repeat at a fixed distance down the page
Estimated 2 min to 5 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- If a mark repeats at a fixed distance down the page, do the checks in this section.<1mReport a problem with step 1, Marks that repeat at a fixed distance down the page
- Measure the distance between two identical marks with a ruler.<1mReport a problem with step 2, Marks that repeat at a fixed distance down the page
- Compare the measured distance with the manufacturer's repeating-defect chart for this model before you choose a part.1mReport a problem with step 3, Marks that repeat at a fixed distance down the page
- The chart names the worn or damaged part for each distance.
- If the printer documentation has no chart, write the exact distance on paper and contact support.<1mReport a problem with step 4, Marks that repeat at a fixed distance down the page
Toner that smears or rubs off the finished page
Estimated 1 min to 2 min
Source: The toner rubs off the paper or labels. How do I correct smearing or poor fixing? · tier 1 · accessed 2026-08-04
- Print a test page with a large black area.<1mReport a problem with step 1, Toner that smears or rubs off the finished page
WAIT FOR THE PRINTER AND THE PRINTED PAGE TO COOL BEFORE YOU TOUCH THE PRINT.
The fuser inside the printer is hot and can burn your skin.
- Touch the black area with one finger.<1mReport a problem with step 2, Toner that smears or rubs off the finished page
- Look at your finger for a grey or black mark.<1mReport a problem with step 3, Toner that smears or rubs off the finished page
- If toner is on your finger only after a hard rub, this is normal for a properly fused page.<1mReport a problem with step 4, Toner that smears or rubs off the finished page
- Brother states that the material in toner reacts to heat, pressure and friction.
- If toner comes off with a light touch, the fuser is the likely cause.<1mReport a problem with step 5, Toner that smears or rubs off the finished page
Decide the part and the next step
Estimated 3 min to 12 min
- Write the section that matched the defect on paper.<1mReport a problem with step 1, Decide the part and the next step
- Write the likely part from that section on paper.<1mReport a problem with step 2, Decide the part and the next step
- Find the printer model number before you order a replacement part.<1mReport a problem with step 3, Decide the part and the next step
- The toner cartridge, the drum unit and the fuser are specific to one printer model.
- Read your printer's own instructions for the exact replacement steps.1mReport a problem with step 4, Decide the part and the next step
- Contact the manufacturer's support line if the defect matches no section, or continues after you replace the likely part.1mReport a problem with step 5, Decide the part and the next step
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- toner cartridge
- Also called: toner, ink, printer ink, the black cartridge, laser ink
- imaging or drum unit
- Also called: drum, drum unit, imaging unit, imaging drum, OPC drum, photoconductor
- fuser unit
- Also called: fuser, fixing unit, fixing assembly, the hot roller, fuser assembly, maintenance kit
- print density
- Also called: print darkness, toner darkness setting, print intensity
- repeating defect
- Also called: repeating marks every few inches, marks that repeat down the page, a mark that comes back on every page, periodic mark
When to use a professional
Match the part to the evidence before you order it. A part that does not match the defect wastes money and does not fix the page.
Get the exact part number from the printer, not from memory. The toner cartridge, the drum unit and the fuser are specific to one printer model.
Contact the printer manufacturer's support line when the defect matches no section here. Also contact support when the defect continues after you replace the part the evidence pointed at.
A wrong part more than once can mean a fault inside the printer. A support technician must examine a fault like this.
This page names no injury risk inside the printer beyond the hot fuser. Do not open the printer to inspect or replace a part while it is running or still warm.
Common questions
Why does my laser printer have faded print even though I just replaced the toner?
Because faded print does not always mean the toner cartridge. Brother's own troubleshooting sequence checks the print density setting first, then the drum, and only recommends a new toner cartridge if the page is still faint after that. Canon separately names deteriorated parts inside the toner cartridge as a cause of faded printouts. If your toner level display still reads normal or high after a fresh cartridge, the imaging or drum unit is the more likely cause, not the toner.
What causes a vertical line or a black streak on every printout?
A line or a streak that stays in the same place on every page usually traces to the toner cartridge or to the imaging or drum unit, and sometimes to dirt on the path the paper follows. Brother's documentation ties one specific vertical stripe to a part inside the drum unit. Canon's documentation separately names a dirty print-fixing area as a cause of streaks. Check the toner level display first, since it is the easiest thing to rule out.
There are marks that repeat every few inches down the page. What does that mean?
A mark that repeats at a fixed spacing usually comes from a part that turns once per that spacing, so the spacing itself identifies the part. This page will not print a spacing figure, because the same spacing names a different part on a different printer model. Measure the spacing with a ruler and compare it with your printer manufacturer's own repeating-defect chart, which most laser printer makers publish for their models.
Toner smears when I touch it, or rubs off the page. Is that normal?
A small amount of toner from a hard, deliberate rub is normal. Brother states plainly that toner reacts to heat, pressure and friction, and that rubbing an image with excessive force can remove some of it even on a properly fused page. Toner that comes off with a light touch, or that smears across the page on its own, points at the fuser — the part that uses heat and pressure to bond toner to the paper.
Is a faded or streaky laser printout the same problem as running low on inkjet ink?
No. An inkjet printer sprays liquid ink through a printhead, and its faults and fixes are different — see this site's HP OfficeJet print-quality record for that process. A laser or LED-page printer instead uses a toner cartridge, an imaging or drum unit, and a fuser, and the word toner on a printer that has ink cartridges is usually a search habit, not a sign of the wrong part.
How do I know if it's the toner cartridge, the drum unit, or the fuser?
Match what you see on the page to one section of this record. Faded or grey print points at the toner cartridge or the drum unit. A repeating line or streak points at the drum unit. Marks at a fixed spacing point at whichever part turns at that spacing. Toner that rubs off after printing points at the fuser. Confirm the printer model number before you order any part, because all three parts are model specific.
Can I keep using the printer while the print looks wrong?
For a faded, streaky, or smudged page, yes — none of these defects on their own is a safety problem, only a print-quality one. The one caution this page carries is about handling: let the printer and the printed page cool before you touch fresh print, because the fuser inside the printer is hot enough to burn skin during and shortly after a print job.
Related procedures
- How to find and record the model and serial number of every appliance in the house
- How do I replace the toner cartridge and the drum unit in a laser printer?
- How to fix streaky, faded or lined printing on an HP OfficeJet Pro 9010 series printer
- How to run a nozzle check on an inkjet printer and decide whether to clean the print head
- How to fix a paper jam on an HP DeskJet 2700 printer
- How to fix a printer that says offline in Windows 11 and Windows 10
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 1Faint, light, faded, or blank printed pages
- Tier 1The toner rubs off the paper or labels. How do I correct smearing or poor fixing?
- Tier 1Streaks Appear (Troubleshooting)
- Tier 1Printouts Are Faded (Troubleshooting)
- Tier 1Maintenance and Inspections
- Tier 1The Toner Does Not Fix onto the Paper Well
Revision history
Current version 1 · updated 2026-08-04 · next review due 2027-08-04
- v1 · 2026-08-04First draft. Built from Brother's own support documentation (help.brother-usa.com, mono laser HL-L23xx series) on light/faded print and on toner rubbing off, and from Canon's own online manual portal (oip.manual.canon) for the imageCLASS MF753Cdw, the imageCLASS D530/D560 series and the imageCLASS LBP7110Cw, covering streaks, faded printouts, the fixing-unit heat warning, and the internal-fault escalation path. Every source was fetched and read directly; none was cited from a search-engine summary alone. Two categories of source were deliberately excluded after an attempt to read them: HP's support.hp.com print-quality documents render client-side and returned no extractable text on repeated fetch, and Xerox's support.xerox.com and office.xerox.com pages returned HTTP 403 on every attempt. Per the sourcing rule that a source not read is not a source, nothing from either domain is cited, quoted, or relied on for any claim on this page, including the widely repeated repeating-defect-ruler millimetre figures, which trace to toner-reseller blogs rather than to a manufacturer chart and are deliberately not printed here. No repeating-defect spacing number, and no fuser operating temperature, is published as a value: both are routed to the reader's own printer documentation, because the one manufacturer number found for either quantity (a Brother label-material heat-tolerance figure, 392 F / 200 C) describes what a label must withstand for 0.1 seconds, not the fuser's operating temperature, and is specific to Brother's own machines besides. Scaffolded as doc_type diagnostic because the topic is explicitly a which-part decision; the separate replace-toner-and-drum-in-a-laser-printer backlog candidate is the follow-on repair page and is not yet drafted, so it is not linked from related. professional_boundary and the hot-fuser hazard are the two required safety elements; no other hazard applies because every check in this record is external to the printer housing.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.