Canon ip4700 Magenta Problem

[IanYY]

{Edit} Canon ip4700 {/Edit}

Image 1 shows the problem I am having with Magenta - lighter coloured stripes when priinting blocks of various shades of Magenta. All others colours print OK.

Image 2 shows the cause. This is a magnified extract from the Service Test Print (which shows the problem more clearly than a standard nozzle check). You can see that the top 4 lines are not printing clearly or darkly enough. Ignore the black line where I scribbled on the image!

I am assuming that I will be able to fix the unclear printing by head cleaning. I've not managed to fix it yet running several standard nozzle clean operations, so this may require some Windex.

But I am more puzzled by the fact that the top four lines are all offset slightly to the right. Is this something to do with timing which may need cleaning or adjustment?

Any comments appreciated.
Ian

 

[stratman]

Nature abhors straight lines. This is not a clogged print head. Either your print head or logic board have malfunctioned. Unless you are getting an error message then there is no easy way to tell what has malfunctioned. However, chances are it is a bad print head based on past experience with others on this forum.

Concerning the vertical missing ink, see http://www.nifty-stuff.com/forum/viewtopic.php?pid=56408#p56408 and http://downloads.canon.com/cpr/software/mf/MP620_TimingStripCleaning.pdf for information about the timing strip.

 

[The Hat]

Its not looking good for your print head (All ready said) but Id try cleaning the timing strip as a last chance gasp.
Anything is possible, its worth a try youve nothing to lose..

 

[IanYY]

After a bit more investigation, I think I have to agree with Stratman and Hat, and accept that this is a printhead problem.

I tested the printhead in a spare ip4700 (which has a different printhead fault), and the fault moved to the new printer ruling out the logic board and the timing strip.

I thoroughly Windex-ed the printhead - which made a very minor improvement, but not enough to count as a cure.

I cleaned the timing strip, to no effect (as expected).

The end result gives this nozzle check ...

You can see that the top lines are extremely faint (you need to look really closely to see them at all) and are slightly offset to the right. There is a magenta splash at the top of the black bar on the same lines. The bottom few magenta lines aren't perfect either.

If I print on plain paper using the "high quality" setting, the overall effect is acceptable (the faded magenta lines almost disappear). It's not good enough for photo printing, but good enough for general office use. So there is still some life left in this printer.

Ian

 

[The Hat]

If you intend to keep using your printer you could try a manual print head alignment.
It wont improve the faded print quality any but should align the magenta nozzles a bit better that they are now..

 

[Grandad35]

This is based on observations made over the years, and is pure conjecture.

The nozzles are spaced above the paper and rely on the ink drops being ejected directly toward the paper. If there is debris at the nozzle exit, the drops can be directed at an angle, causing what you see. Try printing an extended nozzle check - these instructions may or may not work for your printer.

 

[turbguy]

Or the print head nozzles could just be worn out, that's what I would expect...

Wayne

 

[websnail]

It's VERY unlikely to be related but there's some instances when the ink in the nozzles can be getting on a bit (age wise) and it starts causing "odd" misfires that shoot off in somewhat random directions.

Tend to see this more across the whole nozzle check and mainly in Epson Dye inks (Cyan is one it used to happen with a lot).

 

[IanYY]

... debris at the nozzle exit ...

I think this might be worth a gamble.

The printhead nozzles have already been stood/soaked in Windex, but I have been very wary of direct physical cleaning of the nozzles (apart from a gentle wipe when drying the printhead). Next week (next time I will have an opportunity), I will try wiping the nozzles more aggressively - a lint-free cloth dampened with more Windex seems appropriate.

Ian

 

[PeterBJ]

Hi IanYY

I think it's a printhead problem, and that some printhead cleaning might fix the problem.

I have just experienced the same on a smaller scale with a Pixma 3600. Here is a picture showing part of extended nozzle checks from service mode before and after ordinary printhead cleaning from the maintenance tab. See top right corner of the photoblack pattern. Note also how much better high resolution paper is compared to ordinary copy paper for printing extended nozzle checks. The top is before cleaning, printed on ordinary copy paper, the bottom is after cleaning, printed on high resolution paper, click to enlarge: