Sharp AR-M450 Random lines

[austonrush]

Good morning,

We've been stumped with an ongoing issue with an older AR-M450 producing random lines down the page. The location and density of the lines changes print to print (per job not per page), we've changed the entire developer unit, drum, transfer roller in the past and it's had no effect. I've snapped a video of the drum as it rotates, and you can watch the defect in action. Unfortunatly as it does this during a power cycle, it coats the transfer roller and also gets toner down the back side of the page.

It's printing across the long edge, so the horizontal lines are in the direction of travel.

Any thoughts?
IMG_20120801_085613.jpg

[lky1978]

Have you change main corona unit?

[austonrush]

Re: Sharp AR-M450 Random lines

Cleaned the unit, but not replaced it. We're not seeing any backrounding, and the random nature of the lines has me doubting it's a surface charge issue.

Have you seen a corona produce this kind of defect in the past?

Thanks!

[Northwestservice]

Re: Sharp AR-M450 Random lines

is the grid tight on the corona unit?

[austonrush]

Re: Sharp AR-M450 Random lines

I removed, cleaned and reinstalled the grid.

I didn't have a torque value for the adjuster onsite, and put on what torque on it I felt the grid would manage. I did remove it a second time and put another turn on the screw, however I don't want to fracture it as I don't have a spare on-hand.

Anyone know just how sensitive is that grid to the tension adjustment? It certainly sits nice and flat.

[Northwestservice]

Re: Sharp AR-M450 Random lines

well it needs to be firm the grid wont break but the plastic housing will...... i rebuilt one of these drum units before and i found that the felts at the ends of the cleaning blade do wear out and effect the cleaning towards the edges? when i clean the grid i spary a piece of paper with windex just loosly wiggle the grid in the pool of windex on the paper. then blow it dry with air. then i spray it with 99% isoporpoponal let it air dry. lint from a rag will get caught in the grid??same thing with the charging what ever you want to call it (filiment)make sure there is no lint stuck...

[austonrush]

Re: Sharp AR-M450 Random lines

We've rebuilt the drum unit (new felts, and blades) in the past, and they're wearing again. The edges of the drum are collecting some toner, but they're off the printed page still.

I didn't see any lint on the grid, but it was a very challenging environment with poor lighting and could have been missed.

I'll see if we can just order a new grid/wire assy complete and replace it as a unit.

Thanks for the help, i'll update the thread with any results.

[mojorolla]

Re: Sharp AR-M450 Random lines

Looks like a bad charge unit all the way. Anytime I see those wavy "smoke" lines, time for a charge kit.

[JustManuals]

Re: Sharp AR-M450 Random lines

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