E-studio 3511, dirty with color mode, clean with black&white mode

[htb2k5]

I copy/print 1 or many pages with black&white mode on E-studio 3511. It output clean and clear page. But with color mode, it output detail text and image pages but dirty background.
I see good transfer belt cleaning blade. I don't find out cleaning blade bias connection.
Please tell me where Cleaning blade bias connection.
and please tell me how end dirty background

[Mr Spock]

the cleaning blade has no bias. check the dev unit ground on the front of unit. I would suggest replacing the machine.

[ivovb]

Check PM counters and change as necessary. Check color developer units - doctor-sleev gap, toner supplying, bias, etc.

BR

[htb2k5]

No volt (-1000V) at CN487 when check drum cleaning blade bias(03-428).
No volt (-1000V) at CN487 when copy/print color or black&white.
I think error on HVT board or LGC board. The drum cleaning blade is conductive blade. now, it clean mechanically, not electrically.

[emujo]

In some cases, a piece of paper will make it past the cling sensor and jam on top of the X-fer belt. This will not generate a jam code, B&W copies will look great, but, since the X-fer belt has to make 4 passes to produce a color copy, the paper will rub the X-fer belt and give the symptoms you descibe. I am assuming you haven't actually looked under the bridge area as it is a pain to get to since you have to remove finisher, and bridge cover to get there. Emujo

[ivovb]

In some cases, a piece of paper will make it past the cling sensor and jam on top of the X-fer belt. This will not generate a jam code, B&W copies will look great, but, since the X-fer belt has to make 4 passes to produce a color copy, the paper will rub the X-fer belt and give the symptoms you descibe. I am assuming you haven't actually looked under the bridge area as it is a pain to get to since you have to remove finisher, and bridge cover to get there. Emujo

You are right about the paper. I have see such a problem many times. But htb2k5 talks about backgroundnot poor cleaning. It is good idea if htb2k5 can provide some copy samples.

BR

[htb2k5]

I changed new HVT board. I adjust codes: 05-338 = 115 (max),05-339 = 990(max) ; 05-250 = 4400, 05-252 = 4900. It copy/print with clean background color/blackwhite pages.
However, it make no clean image on transfer belt. There are many cyan, magenta, yellow toners on transfer belt -> many waste toners. Please help me to eliminate waste toners waste toners when to make image.

[ToshibaTech]

Are the copies coming out looking ok? How much waste toner are we talking about?

[Mr Spock]

The hvt pwb should come with a piece of paper with the settings that it was calibrated with. Use these settings, if you do not then you are masking the real problem and causing another (pulling developer or toner).

And you are correct about the bias on the cleaning blade (did not remember that from class 6 years ago) the bias connector is located in the rear of the unit next to the main charge connector (in line with the pivot point of the blade. This can cause the copy quality issues as well.