Banding and gradation problems in full color prints mx-5500

[Froota]

Hey,

We have a problem on a Sharp mx-5500 with fiery installed. This machine only have 200K on the count, and is already giving qualityproblems on colorprints.
For example: The customer want to print a flyer with the Scottish flag as background. The bottom of the paper is correctly filled with the typical blue color, while the top of the paper is more like a dark purple color instead. If you look very good, there are some darker and lighter bands and stripes in it.

We replaced all the drums and developer, removed the yellow shutter to the laser, cleaned charge, also tried without fiery, took some skyshots (with almost the same result),....

Before jumping into high costs by replacing drive units etc., i just wanted to know if someone have had same problems on this machine.

(we already made all calibrations)

regards,
Froota

[glewisme]

You say banding,is it front to rear or lead to trail ? Also is it set to DEF1,DEF2 or DEF3?

[Froota]

You say banding,is it front to rear or lead to trail ? Also is it set to DEF1,DEF2 or DEF3?

Hey,

It is from the front side to rear side, dark to light. We haven't tried any other colorbalance than the standard. (DEF1)
I will try it tommorow or at least friday by replacing all the drums, and maybe by using another color balance target.

regards,
Froota

[Toner Boy]

Transfer trouble? Make sure all of your charge rollers in the primary transfer belt are in their proper places (closely checking yellow).

[OMD-227]

Is the machine sitting level?

Dont even touch the main drive unit etc etc. It has nothing to do with that. This is a C/Q issue, that sounds like either a color dev, dirty LSU, machine level setting or dirty main charge. A main drive unit problem would be completely different.

First thing I'd check is the self-test prints in sim 64-01 & 64-05. You will see ALL problems very clearly when using these tests. Set 64-01 as: A = 11, B & C = 2, and D = 255. You will get 4 halftone blocks across the entire page.
By reading your description of the color fault, you will easily see your problem on that page that it will print for you. You will see which individual color drum & dev is causing an issue, or if the fault is across all 4 halftone blocks, you can bet the problem is either Transfer Belt Unit or Fuser, depending on the image output.

To me, it sounds like a problem with the CMY developers. Did you change the set at the same time? What was the dev reference values? You mentioned that you only cleaned the grids, but replaced the drums. With the machines counter, I can guess that the color maintenance is due or near-due. Did you replace the grid units/cleaning blades as well as the drums. Which drum/drums did you actually replace? It is possible to replace the entire drum unit with one from a MX2300-4500N as they fit exactly the same. You only need to change the green grid cleaning shaft over as it is a different length.

You mentioned that you removed the yellow shutter........? Why? That is only if you have a complete color channel drop across the whole page, not just a slightly lighter color toward one side. The problem is not the shutter. This is also nothing to do with a particular color balance target. That would affect the page as a whole, not just one side or area.

As far as the transfer rollers go, within the belt unit, these are screwed into place with a small white cover, preventing them from dislodging inside the transfer belt unit assembly. Unless you can see an obvious fault on the 64-01 self test prints I mentioned above, which would contaminate or affect the whole page, the problem is not the transfer belt.

Make sure the firmware is up-to-date, machine is sitting level and has no direct sunlight on it if possible. Perform full color calibration using sim 46-24 & 67-24. Run the self test 64-01 with the item settings I mentioned above. The output page will show you what is wrong. It will lead you straight to the problem. It is sometimes difficult to eliminate something or correctly diagnose a certain fault when you are printing high coverage color. The self test prints will show you the 4 colors separately on the same page. You will see what I mean.

If possible, attach a sample page here.

[Froota]

Make sure the firmware is up-to-date, machine is sitting level and has no direct sunlight on it if possible. Perform full color calibration using sim 46-24 & 67-24. Run the self test 64-01 with the item settings I mentioned above. The output page will show you what is wrong. It will lead you straight to the problem. It is sometimes difficult to eliminate something or correctly diagnose a certain fault when you are printing high coverage color. The self test prints will show you the 4 colors separately on the same page. You will see what I mean.

If possible, attach a sample page here.

Hey,

thx in advance to help, but the problem isn't over yet. I can not post a scan, because it isn't that clear, and nearly visible.
I printed out a self test and the banding is slightly visible but in all the colors. The colors by themself are fine.
Firmware is up to date, and the environment is good. (copyshop)

So I started to replace the normal things, because i had my doubts about the last maintenance.
I replaced drum-cleaning blade-corona for all the color units, and also the 3 development UNITS, but no result.
Then I replaced the 2nd transfer belt, and tested with a new 1st transfer UNIT, but still no result.
At the end I dismantled the lsu, and cleaned the 3 mirrors, and made a full calibration, but the problem remains.

Fusing is the last tihing i can try, but then i don't get the logic about that.

Could it may be some thing about memory or something? processing of colors? I don't know anymore.


regards,
Froota

[Toner Boy]

I have seen inconsistencies with the drums, even new. Specifically to the banding issue, 4mm bands (F to R) that seemed to be related to one drum that would not show up on test prints, only when combined w/other colors; but I'm a little unsure of what your image problem looks like. We were trying to push this machine into a high quality demanding environment and its 'business color' even w/Fiery wasn't gonna cut the mustard compared to good Canon, KM or Xerox (and I'm a Sharp guy), mostly due to inconsistencies over large background areas of a color mix like blue or green. It was an MX-3501N but I think the output would be relatively the same.

[OMD-227]

The 4mm bands that I think Toner Boy is talking about, is the bands that show when you replace a complete drum unit. The point of contact between the drum & blade, which has been sitting there since production, develops a non-visible spot on the drum surface which on every rotation causes the repeating bands. If you refurbish a drum unit with the MK kit & drum, you never get those bands.
It takes approx 500 pages for the contact spot on the drum surface to completely disappear. I've even tried powdering the new drum surface, but I've found the problem disappears by itself. It seems the longer the production date of the new drum unit, the more serious & noticeable the banding is.

Froota, you must remember that the first series MX machines were all only 600dpi resolution. On a standard print driver setting, there can be various repeating areas on the page which are slightly lighter than other areas. Even on the C-Dragon machines that have the PTC corona unit. All the first MX machines from the MX2300N upwards all did this.
The image problem you are talking about is not fuser unit related. From what I read in your first post, I take the problem as being half of the page is slightly lighter than the other half. You have already replaced the consumables and parts which usually cause this problem.

I've had clients in the past who have previously had a Canon or Xerox box in where the Sharp is now and they have complained about the speed or image quality. In all occasions, the other machines had a Fiery, which obviously helped with the ripping speed and overall color reproduction. If you have a play with the pc driver settings, make sure the color is set as 4bit, change to custom mode and adjust settings there. You will get better (or worse) image quality through driver change. If the self test pages in sim 64-01 & 64-05 all look fine, and you have done all color calibrations (including the jig tool), then there is not much more you can do other than try the driver setup changes.

Really need to see a scan of what you are talking about. Dont need it to be perfect, just need something to go on.

[Froota]

Hey,

Thx for the reply.
The problem is that our customer want to stop the contract because he's really dissatisfied about the quality of the machine.
The last 4 days i was at Sharp Netherlands for other purposes, and we tried a lot with a test (problem) document from the customer, but even on the mx-3100n, mx-6201n and mx-7001n from their showroom we got almost same problems.
I think our customer demands too mutch from the machine, and compares it with all his canon machines.
The machines just had only 200K on the count, after almost 2.5 years....

I think that only a commercial proposal can give it another change.....so


so this thread can be closed now. thx all for the help,

Froota