c654 K random shadow

[Synaux]

This seems to only happen on Thick 1 and up. Apparently, this never happens on plain paper.
52765480_359227764929690_5426165036412305408_n.jpg

Random and relegated to black.
That picture says leading edge, but it is the tail end of a 11x17. The leading edge is barely noticeable (have to use a jewelers scope to see it). Second side gets worse, but corrects itself one end. I got lucky with this sample as it happened once when I calibrated all trays/paper types for "centering" and "lead edge" and the only example of a duplexed print shown to me.
All these details are somewhat moot, because I have been shown other examples on 5.5x8.5 prints just as bad, if not worse--throughout.

Figures:
MFP ~375k
Fuser: 250k
Belt: 375K
K rotation time: 12k m
Serviced machine when it arrived on location ~6mo ago used (install, clean, calibrate etc) looks like some things were swapped or replaced.

[Synaux]

EDIT: It LOOKED like k only at first blush, ...but upon closer inspection it is M and C (probably Y) and probably not K. It is very difficult to tell without pulling my microscope out. I will try to post a picture, but having issues getting a good photo.... and have it look like anything....

[allan]

Should then get a code like P21?
Check that shadow for color dots to make sure.

[Synaux]

Should then get a code like P21?
Check that shadow for color dots to make sure.

I stopped by today just to pickup the print to use microscope and maybe get a decent picture--they are definitely C/M dots. I cannot see any Y (or K) until breaking out the scope.
No P21s
Looked at the my notes while there. I had completely forgotten that there were 100+ P-14 codes, no others--cleared 6mo ago--no reoccurring (dismissed as dirty IDCs).
I will approach like it is P-14 related and report back!

Thinking Skew Adj, PHRB (ICP 3) and/or PH (G3 lens)....belt...
A curious and perhaps goofy workaround might be running 1200DPI:

• To be compatible with the high speed printing system, a seven sided polygon mirror and two beam array LD is used.
• In 600 dpi writing, two lines are scanned with two laser beams emitted from two LD elements (LD1 and LD2) arrayed vertically through a single surface of the polygon mirror.
• The LD elements of the two-beam array LD are spaced for 600 dpi use, so that the LD cannot be used for 1200 dpi writing.
• In 1200 dpi writing, one line is scanned with LD1, while LD2 controls the SOS signal.
• To enable 1200 dpi writing, the paper feed speed in the sub-scanning direction is made slow to thereby narrow writing intervals.

[blackcat4866]

I'll be interested in your results. =^..^=

[icemanhi]

Any update? Fighting the same problem for a long time....

I stopped by today just to pickup the print to use microscope and maybe get a decent picture--they are definitely C/M dots. I cannot see any Y (or K) until breaking out the scope.
No P21s
Looked at the my notes while there. I had completely forgotten that there were 100+ P-14 codes, no others--cleared 6mo ago--no reoccurring (dismissed as dirty IDCs).
I will approach like it is P-14 related and report back!

Thinking Skew Adj, PHRB (ICP 3) and/or PH (G3 lens)....belt...
A curious and perhaps goofy workaround might be running 1200DPI:

• To be compatible with the high speed printing system, a seven sided polygon mirror and two beam array LD is used.
• In 600 dpi writing, two lines are scanned with two laser beams emitted from two LD elements (LD1 and LD2) arrayed vertically through a single surface of the polygon mirror.
• The LD elements of the two-beam array LD are spaced for 600 dpi use, so that the LD cannot be used for 1200 dpi writing.
• In 1200 dpi writing, one line is scanned with LD1, while LD2 controls the SOS signal.
• To enable 1200 dpi writing, the paper feed speed in the sub-scanning direction is made slow to thereby narrow writing intervals.

[Synaux]

Any update? Fighting the same problem for a long time....

Actually, yes, just a week ago.

They got a good deal on a transfer belt, which seems to have cleared it up (the problem is the randomness--I was unable to duplicate the issue). If you look at the Theory of Operation section with image processing (or whatever it is called), this makes some sense. Seems like a timing chain like issue in a vehicle for a loose example.

I cannot see anything wrong with the old one--not a scratch--super mint condition and everything seems to be moving perfectly.

Perhaps a worn bushing somewhere? I dunno.

I never did get get the microscope on the prints because...well...I had bigger and cheaper things to do

[Synaux]

Actually, yes, just a week ago.

They got a good deal on a transfer belt, which seems to have cleared it up (the problem is the randomness--I was unable to duplicate the issue). If you look at the Theory of Operation section with image processing (or whatever it is called), this makes some sense. Seems like a timing chain like issue in a vehicle for a loose example.

I cannot see anything wrong with the old one--not a scratch--super mint condition and everything seems to be moving perfectly.

Perhaps a worn bushing somewhere? I dunno.

I never did get get the microscope on the prints because...well...I had bigger and cheaper things to do

I know I had written a retraction on this... I never got any feedback and upon review, I apparently must not have hit "submit reply."

Transfer belt replacement did NOT fix this issue. I sincerely hope I did not make anyone purchase a transfer belt needlessly.

The issue resurfaced again only on thick 1-4 some time ago (same scenario). I was unable to duplicate the issue on plain paper.
It seems that the K is distorting/stretching ever so slightly.

K Dev unit was replaced some months ago, transfer belt replaced, fuser inspected visually with ~75% life left, K drum is about half life, but I intend to try a swap soon. This was the machine I tried to to do the version up on...so if anyone remembers that post, it has new FW as well (lol).

Attached is a microscope pict of--if I recall correctly--is it the void between a "V" at maybe at ~10point font size. This anomaly will appear in a wave-like manner throughout prints.

Dropbox - Microscope.jpg - Simplify your life

[Synaux]

Just an update, replaced K drum unit and the issue has not resurfaced for a few months.

I wanted to make sure this was the fix before posting because of how random the issue was.

Cheers!

[Bix]

Thanks for sharing!
it's crazy how many problems a drum can cause.