Canon i9900 banding problem

[billcotter]

I'm having problems with printing that starts out fine then becomes banded.

Here's an example of one shot. The far right side looks ok, which is the last part being printed. It's dd in that if I print a second copy right away it does the same thing - start banded then clear up for that final small segment. It's not like something finally got flushed clear, as it happens over and over again, same pattern.

and a close-up that shows more of the transition:

I ran a full alignment on the printer and noted that colums F, I and K all have lines in them that don't offer any settings where they look good, like the other columns do.

I tried aligning the printer but those columns still look wrong:

I did a nozzle check and got this:

I have tried cleaning, deep cleaning, flushing the print head with purified water - no change.

Any suggestions?

Thanks

Bill

 

[The Hat]

billcotter
Any suggestions?

I hate to say this but looking at your nozzle check your magenta and cyan have straight lines on them
which strongly suggest an electrical problem with your print head.

You could go for broke and try cleaning the back of the print head with some alcohol and a soft cloth,
you have nothing to lose at this stage in fact try everything you can think of..

 

[websnail]

Does look a little like the problem is as TH suggested with the Cyan but I'm less sure with the Magenta...

My first thought was that the cartridge is not feeding ink properly and could be starving the printhead of ink in which case replacing or flushing the cartridge may well resolve the problem rather than the printhead being the culprit.

 

[Grandexp]

I won't give up the print head so quickly. If it printed a few inches fine then started the banding the print head is at least good for the first few inches. I don't know though if the print head electronics would be OK for the few inches then went bad afterwards.

 

[stratman]

If it printed a few inches fine then started the banding...

OP stated the exact opposite occurred.

 

[Grandexp]

If it printed a few inches fine then started the banding...

OP stated the exact opposite occurred.

This is what the OP said: I'm having problems with printing that starts out fine then becomes banded. Am I missing something elsewhere?

 

[Grandad35]

On my i9900 the paper only advances 1/8 of the print head height for each pass of the print head when printing photos, so that the entire print head is used to print each section of the image. This gives an 8:1 overlap so that if a few nozzles aren't firing you will still get at least 7/8 of the appropriate amount of ink in all areas of the print - the missing 1/8 is barely noticeable in most circumstances.

However, at the end of the print, the paper stops advancing in this manner and the last several print head passes are made without advancing the paper or by advancing it in smaller increments. The net result is that the bottom of the paper is printed mainly with the bottom of the print head, not with the entire print head as for the rest of the print.

I cropped out a section of your print from the top right, blew it up, adjusted the tone curve to darken it and exaggerate the differences in color, converted it to the CMYK color space and then split it into its C/M/Y/K channels to get an idea of which ink was causing the bands (this splitting action matches the ink colors closely, but not perfectly). The yellow and black channels show no ink, as would be expected from the sky colors, which are normally a blend of C and M. The magenta channel shows slight banding on the left, possibly corresponding to the missing narrow band on the magenta nozzles. Note that about 5 (1/8 print head width) bands are clearly visible in the cyan channel, and that dark area to the right is approximately equal to between 3 and 4 band widths approximately the width of the bottom half of the print head that is working properly. Does this explain what you are seeing?

Try printing something without dark cyan, so that only the PC ink is used. I'll wager that the banding problem goes away. Given your Cyan nozzle check, it's very likely that your print head has an electrical fault and needs to be replaced. As others have commented, the magenta nozzles may have an electrical problem or an air bubble in the ink channel. It really doesn't matter, since you have to replace the print head to fix the cyan problem.

 

[Grandexp]

Good observation Grandad35. I am more convinced that it is an electronics problem now. If it is an ink starvation problem the print will show more random patterns of banding. The OP's picture does not look very random. It is indeed very likely an electronics problem.

 

[stratman]

Grandexp:

You are 100% correct. Thank you. It was the following of yours I should have quoted:

I don't know though if the print head electronics would be OK for the few inches then went bad afterwards.

This sounded like you thought it was the other way around. Did you mean this in the context of OP printing one print right after the other?

 

[Grandexp]

Well, I did not pay much attention to the detail of the scan of the OP's print. I misunderstood the OPS words. I did suspect that the print head was only clogged. Grandad35's analysis made it completely clear that the print head is likely suffering from an electronics problem. No I never thought the OP printed two pages. I doubted if the print head with an electronics problem could print fine for a few inches than started to print streaks all over the remaining page. The blown up closeup of the scan looked like a few inches of fine print first.