Smudges usually come from the paper path, the wrong paper or wet ink. Canon's duplex article gives one specific fix: if the back side of the paper becomes smudged during duplex printing, perform Bottom Plate Cleaning in the Canon IJ Printer Assistant Tool, which cleans the plate the paper slides over. Canon's print quality steps also apply: print the nozzle check pattern, clean the print head and check that packing material was removed and tanks are installed. A smudged page after a jam often means the encoder strip or paper path is dirty, so clean the strip gently.
Use suitable paper and set the media type so the printer does not lay down more ink than the paper can absorb; photo paper printed with a plain-paper setting or the reverse smears.
The checks in more detail
Let prints dry before stacking, particularly glossy photo paper. Check for a leaking cartridge or tank and clean the inside of the printer with a soft dry cloth. For spots on scans, clean the glass. On laser models smudges and spots mean toner that is not fusing: check the paper type setting, since heavy or coated stock needs a slower fuse setting, and replace a leaking cartridge. Keep the printer clean, dust-free and level. Store spare paper away from humidity, keep the printer covered when unused and wipe the paper path with a soft dry cloth from time to time.
A clean path prevents most marks. Wipe the visible paper path with a soft cloth only when the printer is off and cool, and check the output tray for ink that has transferred from earlier pages.
Differential
Likely causes of “Canon printers leaves smudges, spots or repeated marks”, and how to tell them apart
- 1
A dirty bottom plate
What separates it There are smudges on the back because the bottom plate is dirty
How to confirm Run Bottom Plate Cleaning, from the maintenance menu or the IJ Printer Assistant Tool
- 2
Wrong media setting
What separates it The paper gets too much ink because the media setting is wrong
How to confirm Match the media type to the paper that you loaded
- 3
A dirty encoder or path
What separates it There are smears after a jam because the encoder or the paper path is dirty
How to confirm Clean the encoder and the paper path gently, with a soft cloth
- 4
Wet prints stacked
What separates it The prints smudge because wet prints were stacked on top of each other
How to confirm Let the prints dry before you stack them
- 5
Toner not fusing
What separates it Toner smudges on a laser because it is not fusing properly
How to confirm Set the paper type and check the cartridge
Before you touch a setting
Record this first — changing settings destroys the evidence
- Where on the page the smudges appear
- The paper type and the setting that you chose
- Whether the smudges appear on duplex prints
- Whether it began after a jam
Try in this order
0 of 7 completedRun Bottom Plate Cleaning
ReversibleRun Bottom Plate Cleaning, using the IJ Printer Assistant Tool on Windows, and then test again to see whether it helped.
Set the media type
ReversibleSet the media type to match the paper, so that the printer uses the right amount of ink.
Clean the path
ReversibleClean the paper path, including the encoder and the rollers, with a soft cloth, and then test again to see whether it helped.
Let prints dry
ReversibleLet prints dry before you stack them, since fresh ink can smear onto the next sheet.
Check for leaks
ReversibleCheck for leaks from the tanks and the cartridges, and wipe up any ink, and then test again to see whether it helped.
Clean the glass
ReversibleClean the glass, if the spots appear on scans, using a soft lint free cloth.
Print a test page
ReversiblePrint a test page, and compare it with the earlier prints, to check the result.
Model-specific
What is true of this model and not of its siblings
- Tank models
- MegaTank printers use ink bottles, so check for spills near the tank caps.
- Duplex
- Automatic duplex models slide paper over the bottom plate.
- Other models this page answers
- These steps also fit models TS9521C, PIXMA TS6420a, G7020, G6020, GX7021, GX4020, Color imageCLASS LBP632Cdw, imageCLASS MF455dw, Color imageCLASS MF656Cdw.
Stop boundary
When this stops being a self-service repair
- !If smudges continue after bottom plate cleaning and correct paper, contact Canon
- !If a laser leaks toner, replace the cartridge
- !If only scans are spotted, clean the glass
Evidence ledger
Sources behind this answer
Duplex settings and limits.
Nozzle check, cleaning and deep cleaning.
Clearing a jam on the TS6420.
Auto Scan and difficult originals.
The company and its products.
Exact questions
Common questions
How do I fix smudges on the back?+
Bottom Plate Cleaning in the IJ Printer Assistant Tool.
Is it duplex only?+
It is common in duplex printing.
Does media type matter?+
Yes, media type matters, since the wrong type puts too much ink on the paper.
Can a jam cause it?+
Yes, a jam can cause smudges, if it leaves ink or dirt in the paper path.
Should I let prints dry?+
Yes, let the prints dry, before you handle or stack them.
Can a leak cause spots?+
Yes, a leak can cause spots, so check the tanks and the cartridges.
Is dust a factor?+
Yes, dust is a factor, so keep the printer covered when you do not use it.