C352 Lines On Copies/Prints

[mrfuser]

Now the copies coming out were beautiful, then suddenly lines showed up going across the entire page, a few millimeters apart and it does not matter whether it is copy or print, black and white or color. I pulled the transfer assembly, cleaned everything, still the lines persist. When I run a white page and stop it half way through getting past the belt the lines are on the half that have gone past. Did something just completely fail on the belt or is there possibly something else amiss here?

I also ran test prints from service mode, CMYK, 64% all that, same result, lines on every page.

Thanks all!

Kelly

[mo0651]

Are they cyan lines on one page magenta on one? maybe post a sample. It almost sounds like a nvram reset had been done and it needs setup procedure done.

[mrfuser]

BizhubC352Lines.jpg
Here is a sample of the trouble.
Which "setup" procedure? I did reformat the HDD because it was giving us grief.

[mo0651]

Boy it is alot easier when you thro in a sample. Looks like your black IU is failing. Make Single color copies. Magenta, Black, Cyan, and yellow. I'm gonna guess that the only one you will have a problem with is the Black. It is hard to clean the charge wires on these, so probably replacing the black IU is necessary.

[mrfuser]

I don't believe it to be the black IU. I can print solid colors in test mode and get the black lines the same. I pulled the black drum unit and tore it apart and cleaned everything, put back in and have the same result.

Any other ideas out there?

Kelly

[907tec]

It sounds strange, but I have had K-IU's cause CQ problems on other test prints. Even when running the isolated test prints with the color units, the K IU can cause lines to appear. If you have another similar model nearby, it would be worth swapping K imaging units. It might still be the ITB, but my money would be on a faulty black imaging unit.

[Mr Spock]

Check the transfer belt cleaning drive unit. I had one fail and left similar patterns.

[oldschool]

This is similar to an issue I had with a C250. Lines showed up no matter what color I ran. The lines faded just before the copier called for black toner. Shortly after the black toner cartridge was replaced the lines darkened again. The black IU was at the end of it's life so I replaced it, problem solved.

[tech51]

I don't believe it to be the black IU. I can print solid colors in test mode and get the black lines the same. I pulled the black drum unit and tore it apart and cleaned everything, put back in and have the same result.

Any other ideas out there?

Kelly

The black transfer roller is fixed and doesnt retract so if your black IU fails you will get lines on the single colour test prints. This holds true for most, if not all the office colour range of machines...

[Stirton.M]

Swapping the image unit with a used one would eliminate that part.

The transfer belt unit, removing the cleaning section will show you if there is an issue there as well. My bet however is something related to the black IU, as previously stated. Another possibility is the erase lamp may be faulty.

[JSC]

Yea I agree, i'd start with the Black iu 1st then move on to the transfer belt, but i'd be willing to bet that the black iu is at fault.

[mrfuser]

Lines Gone!

My hat is off to you all! I ordered and replaced the black IU, lines immediately gone! Still, old IU looks fine. What is causing the IU to fail like that? One minute great copies, the next bad, kinda scarey!

Thanks to all your input!

Kelly

[Stirton.M]

Good show.

The image unit has several areas that can cause this. One is bias failure, in which either the charge unit or the developer mag roller have lost a physical connection to the HV circuit. The net result is an imbalance and toner gets shoved onto a drum that has more positive potential than it should, the developer unit will typically throw developer and toner in great amounts onto the drum, eventually emptying itself. There are variations to this process based on which item lost bias, relative to the rest of the parts involved. The developer unit itself may be completely empty of the developer mixture similar to graphite...think high school physics with graphite on paper, magnet below, graphite stand on end...this process is similar to what happens on the magnet roller, toner rides on the graphite, gets lifted towards the drum, is now referred to as the brush, the higher "positive" relative charge the drum has to the magnet roller, the toner will jump the shorter distance to the drum.

Small theory, drum and developer chamber are at a very high negative charge (electromagnetic induced) at the same potential. Wherever the laser light shines, writing text for example, the surface becomes more positive, relatively speaking, and the toner is attracted to those areas, filling in the written area with black toner to produce the text image. The transfer belt unit has a slightly more positive charge, relative again, that attracts the toner off the drum to the belt. Each colour is overlaid over the other to produce colour blends as needed. Then another roller, with yet again, a slightly higher positive charge relative to the belt, paper rides between and toner is attracted to the paper, where it eventually goes through the fuser, melting the toner to the paper in the finished image.

Another issue, partially related to the above, is that excess toner falls on the charge grid and charge wire, causing an imbalance on the charge, in effect shorting the charge unit against the drum. This part is a bit sketchy as I am only surmising this based on what I know from separate charge, drum, dev unit technologies.

[abilashvk]

Very nice explanation Friend about the Developing procedure.
Apart from this,in tropical countries, where humidity factor is present the charge grid gets corroded as well as the so called 'End Blocks' of corona unit gets fried up.We use to manage by apply slight amount of nail polish/Whitener on the affected portions of grid as well as end blocks & advice the customer for the replacement of IU near future.
These type of complaints might occur all of a sudden also.It can be confirmed by swapping the drum units alone, as naturally lines will appear on next color.Most of the time machine will also show a 'warning indication' on control panel( a P code corresponding to the color of IU which is having the problem.)