Weird banding issue with ET-8550

[hifivoice]

I'm an happy owner of an Epson ET-8550 for about 3 years. Unfortunately a few months ago the drawer had some problems (it didn't come out anymore), and I sent it for repair (luckily within the extended Epson warranty). On the first return, the drawer still wasn't working, so I sent it in again. As a result I got a replacement printer in return.

It looked all fine, until I did print some graphics (using the "Normal" mode. There were all kind of stripes in the print as shown below (size is A4).

When I printed using the "Fine" mode, the print looked fine:

I did all I could do (nozzle check, horizontal alignment, vertical alignment). All looked fine, with the exception of the horizontal alignment for colour, where the bars didn't align:

So I sent the replacement printer to the Epson service again. They cleaned, nozzle checked, but I got the printer back with the message "all OK, the stripes are normal, that is what fine prints are meant for".

I was a bit upset by that remark, as my previous ET-8550 did not have those major issues at all. I got the repairman of the printer on the phone, telling me that in normal mode the printer head is passing the paper only once, whereas with the fine mode it passes the paper twice to fill it up properly.

Now my point is that there are no white stripes, but dark stripes. so even with one pass the paper is filled up too much. So there is a mechanical offset, not a nozzle issue or so. Also with text, you can see there is clearly an offset when printing text, see an enlarged:

The repairman said that this behaviour is absolutely normal for Epson printers, but I tried to search for similar cases, but I cannot find any, and my previous printer did not expose this problem. I do understand a Normal print in inferior to a Fine print (I did see some very small lined patterns in prints of my previous printer), but never stripes of a few mm broad. He wanted to sent me a replacement printer, with the remark it would be exactly the same.

Now my questions on this forum is, (1) did you encounter similar issues with your model, and (2) do you think this is normal behaviour to the extent I see it here?

 

[Fried Chicken]

That's not normal at all

 

[Ink stained Fingers]

Such printout could be a sign that the timing strip needs some cleaning after such a long time of usage.
Could you do a print for comparison - this same text element - with the driver option - bidirectional printing off -
to compare, it's on the 'more options' tab.
The timing strip in question is a small gray band which passes through a sensor on the rear side of the printhead carriage, This stripe should be cleaned after a while of usage - e.g. with a small piece of kitchen paper towel and some drops of a window cleaner.

 

[hifivoice]

Such printout could be a sign that the timing strip needs some cleaning after such a long time of usage.
Could you do a print for comparison - this same text element - with the driver option - bidirectional printing off -
to compare, it's on the 'more options' tab.
The timing strip in question is a small gray band which passes through a sensor on the rear side of the printhead carriage, This stripe should be cleaned after a while of usage - e.g. with a small piece of kitchen paper towel and some drops of a window cleaner.

The printer log says it only printed 150 prints in total, and the timing strip looks very clean/bright, but I will give it a clean later this week (during day time, as in these darker evenings there is not much light).

With bi-directional printing turned off in the driver, it results in the same stripes in the prints.

 

[Ink stained Fingers]

I forgot to consider that you already got a replacement printer by Epson service, the fogged timing strip occurs typically after a longer usage period. Do you see the same letter offset/distortion with bidir. printing off ?
Did I understand you correctly that the banding - the stripes - do not occur with the high quality driver setting ? which other driver settings are you using - e.g. paper selection .

 

[hifivoice]

Do you see the same letter offset/distortion with bidir. printing off ?

Yes, same result.

Did I understand you correctly that the banding - the stripes - do not occur with the high quality driver setting ?

Correct.

which other driver settings are you using - e.g. paper selection .

Nothing special, and all the same as with the previous replaced printer.

 

[Ink stained Fingers]

I need to search for a copy of the service manual to see if there are any specific actions to your problem, I didn't need it so far so it must be somewhere at the bottom of a pile......

 

[PeterBJ]

I searched for a free download of a service manual for the Epson ET-8550 and didn't find any. But here is a commercial download at $5. And here is a free parts catalog.

 

[Ink stained Fingers]

I found my copy of the ET-8550 service manual, it contains a section to adjust banding but it requires an 'adjustment program' as Epson calls its service/maintenance programs. Such service software is available on the internet for a charge. I think the only action you can take is an iterative process to use the alignment function in the driver, using that section which controls the banding you experience - horizontal or vertical - give the parameters different values and do a test print after every adjustment- e.g. your image which shows this banding - and use that set of parameters wlhich gives the least or no banding. This requires several test/print cycles and takes some time but at least you don't need any tools etc.
There is a risk that you can test away the banding for one quality setting in the driver, but it still may deliver banding with another quality or paper setting.

 

[Fried Chicken]

I found my copy of the ET-8550 service manual, it contains a section to adjust banding but it requires an 'adjustment program' as Epson calls its service/maintenance programs. Such service software is available on the internet for a charge. I think the only action you can take is an iterative process to use the alignment function in the driver, using that section which controls the banding you experience - horizontal or vertical - give the parameters different values and do a test print after every adjustment- e.g. your image which shows this banding - and use that set of parameters wlhich gives the least or no banding. This requires several test/print cycles and takes some time but at least you don't need any tools etc.
There is a risk that you can test away the banding for one quality setting in the driver, but it still may deliver banding with another quality or paper setting.

Where did you find a copy of the service manual?

I wouldn't mind having one