Canon PIXMA MX870 Service Manual page 23

Faulty scanning
Network connection problem No printing.
FAX problem
*1: Replace the print head only after the print head deep cleaning is performed 2 times, and when the problem persists.
Paper gets smeared.
The back side of paper gets smeared.
Graphic or text is enlarged on printouts in the
carriage movement direction.
Graphic or text is enlarged on printouts in the
paper feed direction.
No scanning.
Streaks or smears on the scanned image.
No FAX sending or reception.
<2. LIST OF ERROR DISPLAY / TROUBLESHOOTING>
- Logic board
- Purge drive system unit
(1) Clean the inside of the machine.
(2) Perform bottom plate cleaning.
(3) Perform paper feed roller cleaning.
(4) Replace the following item(s):
- Pressure roller unit (if smearing is heavy)
- Print head
the print head)
(1) Clean the inside of the machine.
(2) Perform bottom plate cleaning.
(3) Examine the platen ink absorber.
(4) Examine the paper eject roller.
(5) Replace the following item(s):
- The part in the paper path causing the
smearing
(1) Confirm that the carriage slit film is free
from smearing or scratches:
- Cleaning of the timing slit film.
(2) Replace the following item(s):
- Timing slit film
- Carriage unit
- Logic board
- Scanner unit (for copying)
(1) Confirm that the LF / EJ slit film is free from
smearing or scratches:
- Cleaning of the LF / EJ slit film..
(2) Replace the following item(s):
- LF / EJ slit film
- LF / EJ timing sensor unit
- Platen unit
- Logic board
- Scanner unit (for copying)
(1) Replace the following item(s):
- Scanner unit
- Logic board
(1) Clean the platen glass and the document
pressure sheet.
(2) Confirm the position of the document
pressure sheet.
(3) Replace the following item(s):
- Scanner unit
- Document pressure sheet
- Logic board
(1) Examine if printing is performed properly
via USB connection.
(2) Confirm the network settings.
(3) Replace the following item(s):
- Logic board (for wired / wireless LAN)
- WLAN board (for wireless LAN)
(1) Confirm the FAX settings.
(2) Replace the following item(s):
- Modular board
- Logic board
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*1
(when smearing is caused by