color shifting c6500

[jhbtech]

hi all

I am busy with a konicaminolta c6500 and have a color shift issue on SRA3 300 gsm paper.yellow shifts quite previlentat the trail side of paper.magenta also shifts before the yellow on the same page.I have changed transfer unit,transfer pulse disc,changed transfer belt speeds up and down with still no joy.

On 80 gsm the image is fine.

[Stirton.M]

Appears that your registration sensors may be at fault.

Do a colour registration adjust and see if that corrects the problem. You may also need to open up the machine to get at the sensors themselves and clean them of dust. In severe cases, replace the registration assembly itself...

[jhbtech]

i have replaced that unit as well.currently swopping drum drive unit around.to best describe problem,client is printing business cards with white text in them(24 up)some cards will have yellow in the text and others will have magenta in the text

[HORSE]

White Text in a solid color on heavy stock will do this especially at 300-360mm from lead edge of SRA3, it tends to knock the magenta out by 1/2 pixel and on small text tends to fill in with a red tinge. Like you say do the same job on plain paper and its perfect. Caused by fuser shock transfered up the Tx belt.

Its a limitation of the machine.

Try using a line screen and see if it improves any.

[Stirton.M]

Having a thought....just occurred to me as I read your post a second time through..."some" cards are doing this on a 24 up file? I recall having a similar issue with a client and it turned out the print engine was not at fault, though of course, in your situation, this may not be the problem...but still worth a look.

It is likely the printed document itself. File corruption when being sent to the queue. Resend the job is one approach. Another is to save the file to PDF (in 24up) and print as image when sending. Use another graphics program to render the file and print. Use another PC.

Further tests can be done through tech rep mode to eliminate the engine. In tech rep, test pattern output....

Set all colours at 255, and select pattern 16. Test on light and heavy stocks....if there is a problem with the print engine, this test will show it with a vengeance.

Might be firmware or the PRCB is failing then. Firmware should be at v60.

If registration is fine on light stock, it should be fine on heavy stock too. Belt and drum speed are adjusted based on that variance.

Also, it could possibly be a problem with the fiery rip itself. To eliminate the fiery, create a print port on the client computer that will print direct, instead of the print or hold queues.

[jhbtech]

The machine has become progressively worse over time.total counter is now on 1.1million clicks

[Stirton.M]

The machine is rated for 5 million...so still a long way to go. Most problems are fixable, or there are workarounds...this problem appears fixable...but then, I am not right in front of it to observe what is going on to know for certain.

scans could help some just to verify suspicions.

[jhbtech]

the scans do not show the shift,so i cannot post that.but a better description is we printed a cmyk black text and the yellow has shifted about 1mm from the lead edge of image to the trail edge

[jhbtech]

the scans are not showing the shifting of the yellow and magenta.

[mr.propper]

change the following settigs and your problem is solved.
The cause is a different Drumspeed when use thick paper.
It the same problem as "Drum drive error C-2211, C-2212, C-2213 or C-2214"


DipSwitch 21 - 6 and 7

Bit6 Bit7
0 0 : Default
1 0 : 0.1% up
0 1 : 0.2% up (recommended setting)
1 1 : 0.3% up