Printer Printing Lines or Streaks? Identify the Pattern First
Do not treat every line as the same fault. First decide whether the defect is a repeated horizontal band, a broken element in one color, or a physical smear/transfer mark.
| Pattern | What it suggests checking next |
|---|---|
| Repeated horizontal light/dark bands | Run the banding test; also verify paper type, print quality and model-specific maintenance guidance. |
| Broken elements mainly in one CMYK row | Run the nozzle-check path and compare that channel before/after. |
| Several colors weakened together | Check shared print settings and the controlled tone fields before assuming one color channel has failed. |
| Wet, dragged or transferred streak | Use the smearing checks; the photo analyzer does not classify smear direction. |
Use the controlled pattern to separate two look-alike defects
Printer Vitals measures missing or broken elements in its known line rows separately from repeated horizontal density variation in the banding fields. That distinction is more useful than diagnosing from an ordinary photo or document whose expected pattern is unknown.
Make one change, then print the same page again
If the controlled test points toward a channel problem, use the printer manufacturer's normal diagnostic or cleaning procedure for that model. Keep the paper and print settings unchanged for the retest so an improvement is comparable.
Primary-reference check: Epson support describes white/dark lines as banding and recommends a nozzle check before cleaning when necessary; Canon's inkjet manuals likewise use missing lines or horizontal white streaks in nozzle-check patterns to decide whether cleaning is needed. Device-specific instructions still take precedence.
Manufacturer references: Epson support · Canon nozzle-check manual