PDA

View Full Version : BH-C-280, weird pattern


Custom Search


Hansoon
03-04-2019, 04:53 PM
BH-C-280, weird pattern.

Machine has a total of 120K on the clock 30 color/ 90 B&W. There's a strange pattern on all kinds of paper, with color and mono, doesn't matter. Internal prints and everything it shows al the time even within the leading edge void. The pattern is very fuzzy and looks like - more or less - squares 4x6mm, near the rear edge. Repeating around every +/- 28mm. Barely visible but enough to be bothering. See attachment. It shows best with halftone pattern 65, yellow. But is not restricted to yellow only. It shows with all colors and all circumstances.

Since the pattern repeats around every +/- 28mm (hard to measure exactly cause they are so fuzzy) I looked for any roller or other thing "round" roughly being 9 mm (28 divided by π 3.14159 = +/- 9mm). Did not find anything. A visible inspection of the fuser, drums and transfer belt did not give any indication. Had no parts with me to test.

Later on back home I recalled that inside the transfer belt are rollers with a diameter of 10mm. Had unfortunately not yet checked if there was a bump of dirt on one of them, when I was there cause the surface of the transfer band looked very clean and the customer wanted to leave. Therefore I could not crash stop the machine to do further tests too.

You guys have any ideas?

4191141912

Hans

allan
03-04-2019, 05:27 PM
Wanted to mention those rollers but how are they going to produce toner?
Stop the machine after transfer and check. Get this feeling your fuser could be involved.

Hansoon
03-04-2019, 05:45 PM
Wanted to mention those rollers but how are they going to produce toner?
Stop the machine after transfer and check. Get this feeling your fuser could be involved.

Allan I have seen the strangest things coming from the Transfer Band. Could imagine that the haze of residual toner would be enough to stick to the paper if the transfer belt is being forced up by a bump of dirt.

Hans

allan
03-04-2019, 05:53 PM
Allan I have seen the strangest things coming from the Transfer Band. Could imagine that the haze of residual toner would be enough to stick to the paper if the transfer belt is being forced up by a bump of dirt.

Hans

I have also had spots with the same pitch but not the square patches like that. No clue...:confused:

Hansoon
03-04-2019, 06:09 PM
I have also had spots with the same pitch but not the square patches like that. No clue...:confused:

Coming from the TB?

Hans

allan
03-04-2019, 06:30 PM
Coming from the TB?

Hans

Nope coming from the fuser. Stopped the machine mid print and nothing from the transfer belt.
Not to sure about the makeup of the fuser and don't have one to check.
Costumer did not complain so i opted not to strip the fuser.
On the next call the marks were missing.

So here is a math problem.
If those marks are offset from some thing like the transfer belt or the fuser belt. Then the pitch can not be 28mm consistently if its from the fuser there is no blade to clean it off so every so often the pitch will be less than 28mm and don't want to believe that pitch would be a factor of the fuser belt lenght. then transferring to the paper in witch case it should run out of contaminant soon.
From the transfer belt they can remain constant because every new cycle gets cleaned off.

Now i have confused myself....:eek:

tsbservice
03-04-2019, 06:31 PM
Allan I have seen the strangest things coming from the Transfer Band. Could imagine that the haze of residual toner would be enough to stick to the paper if the transfer belt is being forced up by a bump of dirt.

Hans
I would think the same 👌

blackcat4866
03-04-2019, 06:56 PM
You might want to look at the primary transfer belt. Back when I worked on Sharps, it was a relatively common problem. Toner would collect inside the transfer belt, build up on the facing roller, then press a repetitive texture into the belt. Since the facing roller diameter is not an even factor of the length of the primary transfer belt, the longer it was allowed to run this way, the more complex the pattern, and the closer the repetition. Personally I'm leaning towards the black primary transfer roller. =^..^=

allan
03-04-2019, 07:04 PM
Any noise or vibration going in beat with that would be something i would listen and feel for.

Gaffers01
03-05-2019, 01:19 PM
Could be the k developer roller, i know its a different diameter but i've had a similar mark before and after cleaning the dev roller mark disappeared.

Hansoon
03-05-2019, 02:14 PM
Could be the k developer roller, i know its a different diameter but i've had a similar mark before and after cleaning the dev roller mark disappeared.

Thanks, but K-Developing roller should not come into action when making Half Tone Test Patterns CYM I believe. K-Transfer roller inside the TB yes, since it is constantly engaged.

Hans

Gaffers01
03-05-2019, 02:29 PM
the k drum is always in contact with the transfer belt, thus the k dev roller would be too.

allan
03-05-2019, 02:52 PM
the k drum is always in contact with the transfer belt, thus the k dev roller would be too.

Does not mean it rotates, but not sure myself.

Gaffers01
03-05-2019, 03:35 PM
Does not mean it rotates, but not sure myself.

Im pretty sure there is only 1 drum drive motor on those machines, the k drum is always on and a clutch turns on to rotate the colour drums.

I wouldn't bet my life on it thoughhttp://www.copytechnet.com/forums/images/icons/icon6.png

Hansoon
03-05-2019, 04:09 PM
Im pretty sure there is only 1 drum drive motor on those machines, the k drum is always on and a clutch turns on to rotate the colour drums.

I wouldn't bet my life on it thoughhttp://www.copytechnet.com/forums/images/icons/icon6.png

You are right that the K-Drum is being driven constantly by the main motor M1 which also drives the TB and take up stuff. This likely to avoid that the TB - which is constantly moving - would rub the surface of a not rotating K-drum on one spot since the K-Drum's 1st transfer roller is always engaged as you mentioned.
So both the TB and K-drum are driven constantly and synchronically. The CYM drums are not. They all use one motor the color PC motor M2. The 1st transfer rollers inside the TB for CMY are engaged/disengaged when necessary.

However, the K-Developing unit is not driven constantly, it has its own clutch. Therefore we can almost sure take out of the consideration that the K-Units are being the cause when strange patterns in CYM appear. To complete the picture: The CMY developing units are rotating with the previously mentioned color PC motor M2. Torque to the CYM developing units is coming from M2 and being distributed to the CYM developing units by the Color Dev.Unit Engaged motor M10. So they all are only activated depending on the demand.

Thanks for thinking with me.

Hans

Synaux
03-06-2019, 03:23 AM
However, the K-Developing unit is not driven constantly, it has its own clutch. Therefore we can almost sure take out of the consideration that the K-Units are being the cause when strange patterns in CYM appear. To complete the picture: The CMY developing units are rotating with the previously mentioned color PC motor M2. Torque to the CYM developing units is coming from M2 and being distributed to the CYM developing units by the Color Dev.Unit Engaged motor M10. So they all are only activated depending on the demand.


Hans

I don't think we can eliminate the K dev yet (although this doesnt seem like a dev issue imo):
Unless my beer goggles are extra foggy tonight, it looks like the "Developing clutch/K (CL6)" runs for about half the image process. Don't know if this model had the special firmware to not rotate the color IU's on K only prints as well so there another possible complication.

Do these marks have any color at all? Looks like K only to me. Also, upping the voltage might be able to clean it up?

Hansoon
03-07-2019, 06:06 PM
Gaffers01 was right.

There was a lump of toner sticking to the K-developer roller.

Thanks to Gaffer01 and all of you guys.

Hans
41960

Synaux
03-08-2019, 03:14 AM
Gaffers01 was right.

There was a lump of toner sticking to the K-developer roller.

Thanks to Gaffer01 and all of you guys.

Hans
41960

So I was right? :rolleyes::p

allan
03-08-2019, 06:20 PM
So I was right? :rolleyes::p

Darn it you made me scroll back...
Looking for this injustice of credit. Sneaky.

Toxic
03-08-2019, 06:49 PM
Darn it you made me scroll back...
Looking for this injustice of credit. Sneaky.
I was close :)

tsbservice
03-08-2019, 07:03 PM
I was close :)
Really;)
Next time maybe?
Although I must admit you also was right on money about second transfer.
Keep up this line 👌

Hansoon
03-09-2019, 05:53 AM
So I was right? :rolleyes::p

Yes you too Synaux. Somehow on the small 12" screen of the computer I use in the car I overlooked your post more or less.

Sorry Pal!!

Hans

Custom Search