Toshiba 451c dev unit problem

[makaule]

Color developer unit problem. Toner and developer adheres to the rear side of mag roller making ~1 cm round bump which contacts with drum and starts making color banding on copies. Any ideas ?

Sorry for my english. Hope you understood my problem.

[ss12]

Check the dv blade gap

[makaule]

gap is 0.45 - 0.5. More ideas ?

[rukshan4u2c]

Cant u attach a sample copy took from the printer

[Harry]

Maybe a deformed mylar inside the dev unit!
check also revolver Gap to drum something like broken bushing at the back side. need more information please
Harry

[michaelc]

Have you checked the white plastic brackets which hold the dev units in the revolver unit. If some one has used a different screw this can cause the dev unit to sit out slightly from its correct position. For example, if some one has threaded a screw and drilled and put a self tapping screw in, where the drill has been used there is a slight bit of metal behind the metal plate which the white bracket screws in and this can cause problems to.

[makaule]

https://profiles.google.com/mckaule#mckaule/about

Phone made photo of dev unit..

[michaelc]

When you clean the hardened toner from the mag roller, is the mag roller itself damaged?

[makaule]

I can't say that it's damaged, only when I clean it it looks more shiny. The same problem is with cyan developer unit. Swapped them with one's from another working toshiba and now everything is ok and it made about ~5K color copiers without problems, it means that problem is in units which i still have to repair What can you recomend ? How it could happen at all and with 2 units almost at the same time ?

[rukshan4u2c]

I assume that inside the Dev unit there might be some fault with the spirals that will circulate dev both ways, best thing is to remove all dev from the unit and inspect the movement inside. Specially the wheel that drives the spirals. sometimes there might be hardened dev inside blocking its path that will appear color bandings on copies. Anyway wish u good luck.

[michaelc]

I am not sure, you could check the dev gap and clean the blade down. Maybe some hardened toner got in there. If it happened to both units I would guess the revolver unit but if you have replaced the 2 units and they have done about 5k with no problems then it maybe both dev units.