Black, green, and sometimes magenta marks in image

[petergun1]

I have a Konica 7920 that is printing black, pale green, and sometimes meganta colors primarily at the leading and trailing paper edges. The first two images below are examples.

The third image is of a roller assemble accessible via an access door on the right side of the copier when viewed from the front. Cleaning the roller that is adjacent to the stainless steel metal in the lower half of the image with a t-shirt causes the colors to disappear from the next three to five prints.

I made the images in my first post too large and may have made these too small. I can repost larger images if needed.

A local tech thinks, based on my telephone description, that the issue is the imaging units.

I'd appreciate you thoughts.

[mrwho]

The pictures are too small, but my first guess would be to check the belt's cleaning unit.

[minimerlin]

Be very careful if you touch the roller you cleaned ! It is the image transfer roller and as such should not be cleaned..... but renewed at 125K.

Look at the consumables life in the utility mode..it will show if any items are due renewal.

[petergun1]

The pictures are too small, but my first guess would be to check the belt's cleaning unit.

Here are larger images. The first shows primarily black lines that begin lightly after three prints and progressively get darker as I continue to print. The second is a solid yellow square that offers another view and the third is a copy of the second solid yellow image. The first solid yellow has horizontal lines that are difficult to see in the image. The second yellow image's black lines run 90 degrees to those copied inthe second yellow image -- weird. There is a lot of black toner on the yellow copy -- third image. I wish that I could post better images.

Be very careful if you touch the roller you cleaned ! It is the image transfer roller and as such should not be cleaned..... but renewed at 125K.

Look at the consumables life in the utility mode..it will show if any items are due renewal.

Thanks for the warning, I'll will check the consumables remaining life.

[mrwho]

Well, it still seems to me like a cleaning problem - either on the belt or on the imaging units, although I'd bet on the first.

About the posted images, JPG is way better than GIF (which only uses 256 colors, giving us lots of dithering).

[petergun1]

Well, it still seems to me like a cleaning problem - either on the belt or on the imaging units, although I'd bet on the first.

Is the cleaning problem resolved by replacing the transfer belt or imaging units, or is there a cleaner, scraper, or whatever that must be adjusted or replaced?

Look at the consumables life in the utility mode..it will show if any items are due renewal.

Does the utility menu give access to consumables life counters. The only counters that I found list the number of copies, number of prints, total copies and prints, etc.

[mrwho]

If you take out the transfer belt after a copy, does it appear to be clean or is there toner on it?

And, now that I look at it again, that Windows test page, was it printed while feeding the long or the short side? (A4 or A4R)?

[petergun1]

If you take out the transfer belt after a copy, does it appear to be clean or is there toner on it?

There are toner lines on the transfer belt running. The line's length extends accross the belt's width, left to right when viewing the transfer belt from the left side of the machine.

There are two stripes that extend around the belt's circumference. One is yellow and the other is magenta. They are approximately 1/2 inch wide and are located about 1 inch in from the belt's edge.

And, now that I look at it again, that Windows test page, was it printed while feeding the long or the short side? (A4 or A4R)?

The Window sheet printed A4R. I have include two additional images and each has the word OUT followed by a number. The OUT 9 printed A4R and OUT 4 printed A4. Ten prints were made with the A4R, and five were made in the A4 setting. I picked the prints that best illustrate the issue.

[copytechman]

I'm chiming in with either belt unit blade or iu blade, does it do it in black only (true black mode) as well? (in order to eliminate the colour ius etc?

Regards!
A.

[petergun1]

I'm chiming in with either belt unit blade or iu blade, does it do it in black only (true black mode) as well? (in order to eliminate the colour ius etc?

Regards!
A.

I printed a solid black 7 1-2 inch by 10 inch square and the black lines extend from edge-to-edge across the 8-1/2 inch width.

[copytechman]

As a tshooting tool, (depending on the model), i'd do your solid block test again but stop the copy b4 it gets out of the fuser, then pull the xfer belt and check for proper cleaning.. @ least @ first anyway.. then from there to iu's possibly.

Regards!
A.

[minimerlin]

I agree the black lines look like a belt cleaning problem...has the waste box cleaning section backed up? I have had problems of lines caused by the worm drives breaking off if the unit clogs up. The yellow image unit also looks a bit faulty with the missing coverage.

[mrwho]

IMHO, if you see brown or green (or other composite color) causing dirt or markings, the belt or the fusing unit (or something in between) are the faulty parts, since if it was the IU you'd only get pure colors doing that stuff (CMYK).

[petergun1]

I am going to replace the belt. The unit has 106,000 copies/prints and the belt's life expectancy is 120,000, and based the responces I think the belt is the most likely problem.

I really appreciate everyone's imput.

[petergun1]

It was the belt. Let me thank mrwho, minimerlin, and copytechman for taking time, and having the patience, to help me resolve the problem.