« previous next »
Pages: [1]   Go Down

Author Topic: Gray bands fast scan on print  (Read 1365 times)

  • Guest
Gray bands fast scan on print
« on: June 24, 2004, 06:02:42 PM »
 Looking for some input.  Has anyone seen this problem before;  DT135 started printing intermmitent gray bands some are a few mm wide some are almost 2 inches wide, runing fast scan direction from top to bottom of print.  They are very fuzzy at the edge of the band and is a very light gray band, you can read the print on top of it.  There seems to be no apparent patern to the bars, different widths and random as to when it appears, some times it will print 20 to 30 clean sheets and start up again.  Every once in awhile prints the whole page(s) light gray background.

Changed H boards around with no effect.  Next changed I boards around and at the same time vacuumed around the developer housing and cleand PR ground brush.  After this the machine ran flawlessly for about 3 hours then the problem returned.  This time all I did was clean the PR ground brush and vacuum around the developer housing.  The machine is now running OK, but for how long?  It looks as though some of the developer is building up at the ends of the rolls and on the felt at the edges of the developer.  This build up accumulated in just a few hours, not a lot but a lot more then I am use to seeing.

Is there a coincedence here or could there be a problem with the developer or ground brush? H boards, I boards or the pin connectors? Maybe none of what I have done applies, anyone have a similiar problem and know a fix to it?
Logged

KT6135

  • Forum master
  • **********
  • Posts: 1014
    • View Profile
Gray bands fast scan on print
« Reply #1 on: June 24, 2004, 07:42:07 PM »
 If you are seeing a developer on the mini rug and spray around. Replace the PR tension spring. 9e43230 order 2. Adj to 22mm +/- 2.
Also when the PR belt age, IB/OB will curl and drag the developer out and throw it around the machine.
Check your trimer bar in the developer housing.  :ph34r:  
Logged

  • Guest
Gray bands fast scan on print
« Reply #2 on: June 25, 2004, 02:53:12 AM »
 I would start by checking the ground brush and see if the PR isnt shorting against something.
 I have had bad Dev housings cause this too. If your dev voltage drops momentaraly it could cause more toner to transfer to the PR and that will look like the problem you describe, this could be the dev housing or PWB's or just plain dirty connectors.
 You wont be able to read that drop with a multimeter it happens to fast. Sometimes you can pick a slight drop with an analog meter.
Logged

  • Guest
Gray bands fast scan on print
« Reply #3 on: June 25, 2004, 03:17:38 PM »
 im thinking that your dev house are pr is intermit stalling check for bad drives and belt that are jumping
place your hand on the machine and feel for a thump as its running
if you feel a thump one of your main drive belts are jumping teeth
Logged

KT6135

  • Forum master
  • **********
  • Posts: 1014
    • View Profile
Gray bands fast scan on print
« Reply #4 on: June 26, 2004, 12:13:47 AM »
 I forgot about that one DW. I had that but can't remember if it was a black band or grey!
But definite check also for toner in the pulley at the PR drive.
How do you post test pattern or defect here?  :ph34r:  
Logged

Dwtn Don

  • Senior Member
  • ****
  • Posts: 463
    • View Profile
    • Xerox-Service.com
Gray bands fast scan on print
« Reply #5 on: June 29, 2004, 03:55:51 AM »
 Broken Magnet in Roll #2 ???

long shot, but possible

 
Logged

KT6135

  • Forum master
  • **********
  • Posts: 1014
    • View Profile
Gray bands fast scan on print
« Reply #6 on: June 29, 2004, 09:38:11 AM »
 Think if the magnet was broken, you would have pancaking on the that roller. Seen many of those when I did the rebuilds for X.  definitly a shot to look at. :ph34r:  
Logged

KT6135

  • Forum master
  • **********
  • Posts: 1014
    • View Profile
Gray bands fast scan on print
« Reply #7 on: June 29, 2004, 05:15:31 PM »
 Just had a call, they found the developer drive lost a tooth in the drive belt, it casue to have grey band, intermittenly. Now , yours could be something different. never know if it is electrical/hardware.  :ph34r:  
Logged

  • Guest
Gray bands fast scan on print
« Reply #8 on: July 02, 2004, 07:38:07 PM »
 This machine has been running 24/7 can not keep up with the HFSIs.  I have 4 digital to maintain, a few web press, MO press, windmills, and a whole bindery department along with prepress items.  Got me jumping around here.  I missed changing the developer should have been done a week ago.  Changed out the developer and cleaned the housing and the gray bands have not come back.  Got to hire more help, at last count taking care of over 350 machines running two shifts, and me by my lonesome to take care of it all.

Thanks for the input  
Logged

  • Guest
Gray bands fast scan on print
« Reply #9 on: July 06, 2004, 01:45:15 PM »
 If all else fails, try replacing the developer drive assembly. It's supposed to be isolated from the frame electrically. A bad one will conduct intermittently and give background bars running top to bottom.
Logged

  • Guest
Gray bands fast scan on print
« Reply #10 on: July 06, 2004, 02:26:14 PM »
 Djc What State Are u in there might be a couple guys here looking to relocate to give you a hand  
Logged

  • Guest
Gray bands fast scan on print
« Reply #11 on: July 06, 2004, 03:37:29 PM »
 Located in the middle of the nation, home state of the Huskers.

Boy I wish it were that simple.  We had a guy retire from our maintenance department last Febuary and the company is on a hire freeze until April 21 of 2005.  We just lost our grounds keeper and janitor last week and I am in the process of replacing them.  But if you think you know of some one that is still interested in moving to the corn belt to service Docutechs, Digimasters and Bourg SBMs, I can still take a resume.  Who knows, I might retire from here by then.

Located half way between Omaha and Lincoln NE
Logged

  • Guest
Gray bands fast scan on print
« Reply #12 on: July 13, 2004, 12:23:17 PM »
 DJC, out of interest how old was the dev.

Cam
Logged

  • Guest
Gray bands fast scan on print
« Reply #13 on: July 13, 2004, 11:53:43 PM »
 Cam, good thing you asked, you reminded me to check the HFSIs on the other machines.  Have 12 due on one 9 on the other.  The developer interval is set at 1250K and was at 1875K when started getting the gray bands.  The other machines are around 1550K right now, can't keep up, burried in work.

The developer I use is Xerox, the toner is Nashua.  After running xerographics I lower the toner concentration by about 3 and also reduce exposure some.  Seems to be working great, good print quality and using less toner.  I have also been getting 2.5 to 3mill on the brown PR belts, hope this trend keeps up.

These machines must be getting older, I have replaced dozen of transport rollers, belts, skis for vertical transport, idlers and you name it this year.  Last year I had a month of time in the spring to do a lot of PMs and hardly a jam or shut down from the machines.  This year I hadn't time to check under the hood before they started running the machines hot and heavy, I am paying for it now.

We installed a SBM this year and of course they want to produce every book imaginable with it and some that shouldn't be run through.  I can't tell you how many modifications I have done to the SBM and the DOCs to make it work.  Speaking of the SBM I owe Daryle and R.G. from Tennesee a world of thanks and a few big favors for getting a power supply board for the bypass transport and CIM, and all the extra time with the install.  Saved my butt on the project.  Are there any resonably priced Bourg SBM1s and finishers with bypass transport for exchange on the market.  Maybe looking to purchase three later this fall, rebuild one for here and two for facility in Bellingham.  Plan to install mid January when things slow down a little.

All I can say is thank God I have a lot of 5090 spare parts lying around here and complete finishers, controlers and the like.  Makes it a lot easier to repair and keep running while parts are on order.  And thanks to all the good people regestered on this web site for the help and advice.

DJC  
Logged
Pages: [1]   Go Up
« previous next »