Uneven Density, poor quality Bizhub Pro 1051

[cmitchprint]

We have a KM 1051 we installed in April 2011. We have had issues on and off with uneven density from across the copy (side to side) and we also have 'hot spots' show up that move down the sheet on every copy. Our service has become frustrated to the point they no longer want to address this issue, basically saying this is what we're going to get. But. it's unacceptable, especially when half tones are involved with n-up printing. Many of our perfect bound books are printed 4 up on a sheet so on pages where pictures are at, you can see huge fluctuations on picture quality from side to side and up and down. They've replaced transfer belts, drums, charge wires, etc. to no avail. They tell us that, unlike the C6500, they cannot adjust density from side to side and no one seems to know where these hot spots are coming from. We can print 10 consecutive 11.5 x 17.5" sheets and lay them in a row and see these variations and it's bad and unsellable. Any ideas?

 

[TekniKal]

Are you running the stock at the correct GSM? have you tried differrent stocks? Is the density issue consistently darker on one side or the other? Are you running offset stocks?
Does the machine have the latest firmware? Have you tried adjusting transfer in the paper settings?

 

[cmitchprint]

Are you running the stock at the correct GSM? have you tried differrent stocks? Is the density issue consistently darker on one side or the other? Are you running offset stocks?
Does the machine have the latest firmware? Have you tried adjusting transfer in the paper settings?

We're running 72-91 gsm, #24/60
It does this on all stocks.
It's consistently darker on one side than the other, and we're not talking just a shade, either.
And we have a 'blotch' that moves along the sheet (transfer belt?). Transfer belt has 465,000 out of 750,000 on it. Service is adamant they're not going to replace transfer belt anytime soon. But, the density problem shows up pretty soon after pm kit is installed. Service said there's 'nothing else to replace!" They took samples with them to send off to someone to have a look at. Meanwhile, I'm having to print this one cover page on the C6500 because the 1051 can't do it.

 

[TekniKal]

Sounds like the transfer belt, I would replace the entire assembly to be sure. The giveaway is the "hotspot that moves down the page". The trick is to measure the distance between hotspots and correlate that to either the drum, fuser roller or belt diameter. If it only shows up once in an 11x17 its on the belt. Service should at least be willing to
try changing the belt unit. If it doesn't make an improvement just put the old one back.

 

[cmitchprint]

I'm voting it's the belt. Twisting their arm to replace it 'prematurely' is the problem. They say it lasts 750,000 and by golly, they want it as close to that as possible. At first, they told me 3,000,000! Since I know how to get in service mode, I knew that wasn't right. But, I'm afraid that doesn't explain the density difference from one side to the other. I know you shim drums in the 6500 but they say there's no adjustment for side to side density.

 

[Alith7]

Konica's service (or lack there of) is almost the WHOLE reason we switched to Xerox. our c6500 ran for crap. there was NO color consistency, and we had the the same different color from one side to the other. and we got the same response from them. Out copy centers have NOT switched yet. and the techs are at one of the 4 pretty much all day everyday.

That said, is your lease through Konica corporate or through one of the authorized resellers? If it is Konica Corp, make it your sales reps problem. be a royal PAIN in your sales reps... you know what... until it's fixed. and if you're still not getting a response, than call the sales manager and/or service manager, and keep working your way up. Konica works on the "squeaky wheel gets the grease" concept.

If it's not leased through Konica corporate, than try the same tactics, only if you're not getting a response, call you local Konica Corp branch and see if they can do anything. Or... better yet, call your local xerox rep and negotiate like hell to get the same rates. I have had my Xerox 700i since November. We have over 600,000 clicks on it. the techs have been here... 6 times I think. and 4 of those 6 have been for a problem with the developer unit getting a clog from paper dust. in ALL cases, they were here same day (usually within a couple hours) if I called in the morning, otherwise first thing the next morning. Check through the fine print on your Konica lease. there should be a print quality guarantee clause in there somewhere.