Cause & Cure for end banding on Epson Pro 7880 after power clean?

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#1

Dana, et al,

Any idea what causes banding on the leading and trailing edges of prints on Epson Pro 7880?

See example prints: http://dl.dropbox.com/u/15782478/Inkjetmall%20Forum%20Image/banding%20after%20power%20clean.jpg and http://dl.dropbox.com/u/15782478/Inkjetmall%20Forum%20Image/more%20banding.jpg

The banding occurs right after a power clean (example #1). The banding diminishes after several prints are made after a power clean (example #2). After 3 or 4 prints the banding does not appear to be present.

The examples images were printed using a single ink channel (Yellow, shade 7, slot 8… using QTR-Print) but it is noticeable when printing with any other individual ink channel or multiple ink channels.

The banding only occurs on the leading and/or trailing edges of the paper.

Any suggestions for a cause and cure for this?

Thanks,
John


#2

I have experienced leading and ending edge banding with desktop printers, but never our 7880s’ or other Pro model printers.
How close is the image to the top and bottom of the sheet? What distance from the paper edge does the banding start? Are you printing at 1440 or 2880dpi, and uni or bi-directional speed?
If this banding issue only occurs after doing a Power Clean cycle, but goes away after a few prints, I wonder if you are dealing with slightly restricted ink flow due to old dampers, or possibly an old capping station and/or flushing box (?)
We don’t have a video that demonstrates Pro model cleaning/maintenance, but have written instructions and a video on desktop printer maintenance, which most of the procedures from can be translated and preformed on Pro model printers as well. Are you familiar with our written procedures as well as the desktop maintenance video?

Best regards~ Dana :slight_smile:


#3

Hey Dana,

I did read through the written procedures for the desktop printer maintenance and I watched the videos for the desktop printer maintenance. The capping station, flushing box and wiper were all cleaned thoroughly using piezoflush. They appear to be in pretty good shape. The service life indicators show this printer has not been used much. All of the service life indicators for this printer are at the 81%-100% range (i.e. E*****F).

Each of the two images I posted showing the banding were full 8.5x"11" prints of a 100% Yellow 8.5"x11" image created in Photoshop. The images were printed at 2880 dpi using bi-directional speed with QTR-Print using the 2880 WNSEL quad profile you sent me on JCS Type 5 paper with no gloss coat. What you see in each image I posted is the full 100% 8.5"x11" sheet printed at the maximum coverage area for the 8.5"x11" printer preset in QTR-Print centered. The banding starts right as the printing begins on the leading edge and continues for about 5/8", then the banding begins again at about 5/8" from the trailing edge. In each of these areas (leading and trailing edge) the paper is not moving (which is normal) as the print head lays down the ink on multiple passes of the print head.

Can altitude affect the damper performance, particularly after power cleans? I’m operating the 7880 at about 5500 ft altitude. If you think the dampers might be part of the problem, would you recommend replacing them? Any advice on how to best replace them based upon your experience? I have the 7880 service manual. Replacing the dampers does not appear to be too difficult, although perhaps a bit messy. I believe you mentioned in a previous posting that IJM sells replacement dampers.

BTW, When you experienced the leading and ending edge banding with the desktop printers, did you identify what caused it?

Your thoughts?

John


#4

Hey Dana,

When you experienced the leading and ending edge banding with the desktop printers, did you identify what caused it?

John


#5

Hi John~

In my experience with leading and ending edge banding, this has only been with desktop model printers thru QTR. After discussing this with Roy Harrington, he explained the paper feed in the first and last inch is different than the rest of the paper, and this paper feed in combination with QTR’s tighter dot pattern can cause micro-banding if the image area is within the first or last inch of the sheet. To avoid this, simply leave a 1" top and bottom margin when printing.

Since you are experiencing this with a pro model printer, the desktop paper feed info doesn’t apply. I always maximize my paper use when printing tests, so will push the image to “0,0” top and left margins (which uses the maximum printable areas of .12 top and side margins) and have never experienced the banding shown in the photo you uploaded. It may be worth asking Roy at QuadTone RIP, but as you pointed out it may be something related to the dampers or ink feed system, or based on my experience with desktop leading and tail edge banding, it may also be related to the paper feed (?)

I’m curious, so please keep me posted!
Best regards~ Dana :slight_smile:


#6

Hey Dana,

The banding is its worst right after a power clean when printing a full, 100%, ink channel (one ink channel at 100% ink flow on 8.5"x11" paper… as described above). If I wait an hour or so after a power clean, the banding is greatly diminished. If I wait over night, I don’t see any banding when printing a full, 100%, ink channel.

Since the problem is not persistent (goes away after some time has passed or I print an image), I’m not too concerned about it. I’ll keep an eye on it. If it gets worse, I may opt to replace the dampers to see if that helps.

My current work around is to print one normal 8.5"x11" image using all ink channels right after a power clean. That first image will have banding but thereafter (2nd, 3rd, etc. images) there is no apparent banding.

Now that I have a second 7880, I will be dedicating ink sets to each printer and shouldn’t need to perform any power cleans unless I have bad nozzle clogs which require power cleans or piezoflushing, or I need to switch ink sets.

John


#7

That does sound to be flow related, and quite possibly fixed by replacing the dampers.

Best regards and happy printing~ Dana :slight_smile:


#8

OK. Any first-hand advice for and/or experience with replacing the dampers on 7880’s you’d care to share?

John


#9

Hi John~

I’ve gotten to the point where I can replace dampers in an Epson Pro model printer in about 20 minutes. I always read and follow the field repair guide specific to the printer model I’m working on, and make sure to give myself plenty of time to focus and not rush whenever working on printers- following instructions, using the right tools, focus and patience are very important for a successful outcome. Set up your work area and thoroughly read the procedure before beginning. Wear gloves to protect your hands from ink staining (I like the Nitrile gloves we have- they’re not chalky, and they allow for good movement and grip with my fingers as if I wasn’t wearing gloves), and choose your clothing wisely when working with ink (don’t wear your best clothes when working with ink, just in case you have an accident).

Here some helpful things I have learned over the years of working on these printers:

  1. Remove the top and right side covers to have plenty of room to see and move inside the printer
  2. Place a paper towel under the print head/damper area to catch ink drips or any small pieces that may accidentally fall
  3. Use a magnetized screw driver to help get small screws out and in the hard to reach places they go (and to help prevent them from falling into the depths of the printer)
  4. Raise the ink cartridge locking levers (unlock/open) to stop ink flow- this helps prevent ink from dripping out of the dampers or ink lines when you’re working on the machine
  5. Check each step is correct/complete before continuing

I hope this helps. The first time will take the longest to get familiar/comfortable working on your printer, but it should get easier/quicker the more you work on your printer. Soon, you will have the confidence to do anything it needs and never have to call Epson service again!

All the best- Dana :slight_smile:


#10

Thanks much Dana for the helpful advice. 20 minutes! Wow… You are a pro! That’s one-fourth the time it takes for an Epson service tech to do it.

I’ll dig into the field guide and order the parts… and allow myself at least 10X the time it takes you. Seriously.

Best to you,
John


#11

Speed and accuracy comes with practice: I’ve been learning about and working on Epson printers for about 10 years, and certainly took much longer when I first started. I still clearly remember the feeling of empowerment when I fixed my first printer (which was going to be thrown away with a severely clogged head), and couldn’t even begin to estimate the $thousands we have saved since I’ve been maintaining our printers over the years. I also feel more knowledge about the mechanics of the printers allows me to have a broader understanding of how they work, which also gives me a better understanding of our products, to help with development and support.

All the best~ Dana :slight_smile: