i9900 Strange Behavior

[Bithead]

Recently my trusty i9900 began printing a strange pattern. When printing a 13x19 print I noticed that about every 1.5 inches or so some nozzoles would 'drop out' like they were clogged but then following that it would print fine then repeat the pattern again over and over. First thought was print head was going bad. New print head showed the same pattern. Thought it might be a feed problem with a cartridge. Replaced the cartridges, same result. thought it might be the driver, replaced the driver, same result. Cleaned the timing strip, same result. Cleaned the timing slit disk, same result, cleaned the paper feed, same result.

Nozzle check is fine, both maintence panel and service mode.

I'm stumped.

 

[PeterBJ]

It could be a problem with the paper feed. Apart from the timing strip the printer also has an optical encoding disc that determines the rotation of the paper feed rollers. I think that if this disc is dirty it could cause the paper feed systen to feed a few extra millimetres at some constant distance.

Could you please upload a scan of a printout showing the error?

Page 1-12 in the service manual shows the paper feed motor and the encoder disc.

You find links to the service manual and parts catalog here, I just checked the links, and they still work: http://www.nifty-stuff.com/forum/viewtopic.php?pid=64132#p64132

Edit: I overlooked that you have already cleaned the timing disc.

 

[Bithead]

Thank you Peter for your quick reply. You refer to "optical encoding disc " which I believe I referenced as the "timing slit disk". I've had problems with that before where a half page would print then quit or it could not find "top of page" and not print anything.

I will need to cut up a print and scan the pieces.

Thanks

 

[PeterBJ]

Yes, the disc I called the "optical encoding disc" is the same disc or disk that is also known as the "timing slit disk"

I have tried to look into the paper output of a Pixma 6600D, which I think could be somewhat similar to your i9990: I cannot measure the diameter of the rubber rollers transporting the paper with a vernier caliper, there isn't enough room for that without taking the printer apart, but these rubber rollers look to have a diameter of approximately 1/2", meaning that one revolution of the rollers advances the paper approximately 1 1/2". This makes the disk my prime suspect. You could try examining the disk again using a good light and a magnifier. A window cleaner with ammonia will not harm the disk and might be more effective in cleaning than isopropyl alcohol.

 

[Tudor]

How is the printhead alignment?

 

[Bithead]

Thanks for your input.

I have probably done more nozzle checks and head alignments in the past several days than I have done over the life of the printer.

 

[The Hat]

Thanks for your input.

I have probably done more nozzle checks and head alignments in the past several days than I have done over the life of the printer.

This idea may sound a bit strange but try it anyway;
there is a little plastic wheel on the inside of the printer that may need to be cleaned of dirt or ink splatter.

This picture shows the location of the paper feed gear and plastic sensor wheel thats on all printer,
and you can find yours over to the extreme left hand side of your printer. (Facing)

You may or may not be able to gain access to it without having to take the top cover off at all;
youll only need to clean the disc on the inside so using a cotton bud may be all thats needed.

Its only the dark tinted area that will need you attention but please
be careful and dont bend or damaged the disc (Marked in red) in any way..

 

[Bithead]

Thank You for your response The Hat.

I believe that you are referencing the disc that PeterBJ and I were discussing. I took PeterBJ's advice and cleaned it with windex rather than isopropyl alcohol.

Got it really clean with windex but the problem is still present.

Thanks for your input

 

[Bithead]

PeterBJ wrote:

It could be a problem with the paper feed. Apart from the timing strip the printer also has an optical encoding disc that determines the rotation of the paper feed rollers. I think that if this disc is dirty it could cause the paper feed systen to feed a few extra millimetres at some constant distance.

Could you please upload a scan of a printout showing the error?

I have scanned a couple of pieces of the large print and have uploaded to the forum but I can't work out how to attach them to this thread.

http://www.nifty-stuff.com/forum/uploads/476_epsn030.jpg

http://www.nifty-stuff.com/forum/uploads/476_epsn031.jpg

I've included shortcuts to them.

 

[PeterBJ]

Your images are here:

I see nothing wrong with the printer, but jpg compression might mask the errors. For best results crop the image to show only the essential, and don't use too high a resolution when scanning. This is because only 80 kB is allowed per uploaded image, due to server capacity limitations.

A problem with a stained timing disk would have shown as inserted white (unprinted) lines across the whole width of the paper. I see no such errors. If the print head is not perfectly aligned/adjusted, it can show as fine banding repeated at some interval. In stead of doing an automatic alignment, you should do a manual alignment, using good light and a magnifier to choose the best patterns. It might also be better to use your photo paper for the alignment instead of plain paper, as the thickness of the papers is different.

Is the direction of print head movement vertical in the images? It is hard to see, but are there faint vertical stripes in the images?

If the images don't show the errors, you could try to crop an image hard showing only a small area with the error. This will allow a higher scanning resolution.

You are not the only person having had problems with uploading images, maybe this thread will be helpful?: http://www.nifty-stuff.com/forum/viewtopic.php?id=8281&p=1