Question about Canon PIXMA MP780 All-In-One InkJet Printer

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Canon Pixma MP780 Fax Problem (horizontal line)

This unit puts a broken horizontal line across the bottom of the page on all outgoing black & white faxes sent from the ADF only. It seems to be an image of the edge of the page? Relevant info: -Over 8 weeks, my original unit was completely rebuilt in Canon repair shop and then made the same line. Canon has sent 2 more refurbished units since then and still the same line. The last tech I spoke with said he tested one in their plant and it does it there too. He even said the Pixma MP830 (upgrade of this model) puts out that same line. -4 units did this over different locations -I have changed my phone/fax cord 3 times and faxed from different locations -Outgoing faxes sent from the plate glass and directly from my computer are fine (no line) -Faxes sent in color are fine, even from ADF -All incoming faxes are fine (no line) -Black & White COPIES from the same ADF are perfect (no line) -All other copying, scanning, printing is fine (no line). -Horizontal line is only on outgoing black & white faxes and only when sent from ADF. Is this an unfixable manufacturing flaw/defect or does anyone else have any ideas? After 2 months, Canon tech support has pretty much given up on this and doesn't know what to do. I will try to force a refund if this can't be fixed since I need it for outgoing faxes mainly and it is not very professional looking. It seems strange to not be fixable since lesser priced fax machines from many manufacturers don't do this sort of thing consistently on every page in the same spot like this. Any suggestions would be GREATLY appreciated.

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Re: Canon Pixma MP780 Fax Problem (horizontal line)

Solution is here:

Posted on Aug 22, 2007

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1 Answer

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1 Answer

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Check out the Easy Setup Instructions available here. If you can neither send nor receive faxes, you may not have the phone line connected to the correct port, see page 34 of the guide. Also check what receive mode the machine is set for. Pages 42 and 43 explain the different options and how to change the receive mode.

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Jun 26, 2008 | Canon PIXMA MP780 All-In-One InkJet...

3 Answers

Canon Pixma MP780

Yep your printer is nearing service time. This involves changing the waste ink pads and resetting it.

you could reset the printer without changing the wate ink pads but you risk damaging it

What i do is take the pads out wash them and replace them.

the waste ink pads are the pads the cartridge rest on whan itsn in neutral position

THE SERVICE MANUAL FOR YOUR PRINTER *step by step instructions in repairing it) is here

and here


Dec 18, 2007 | Canon PIXMA MP780 All-In-One InkJet...

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