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mojorolla
05-19-2021, 07:40 PM
454e with CQ issues on copy and print we have laying around the shop. I have 6 of the slower 4e units but of course none of this series.
Have swapped drum and dv units, transfer, reseated laser and connections, firmware, the usual suspects. A panic stop shows that these density variations are occurring before the fuser.
I am leaning towards the laser unit. From the test prints, it looks like one of the laser diodes is failing.
Looking for a second opinion before I waste time or $$ on this older unit.
Thanx
491884918949190



:)

copyman
05-19-2021, 10:16 PM
454e with CQ issues on copy and print we have laying around the shop. I have 6 of the slower 4e units but of course none of this series.
Have swapped drum and dv units, transfer, reseated laser and connections, firmware, the usual suspects. A panic stop shows that these density variations are occurring before the fuser.
I am leaning towards the laser unit. From the test prints, it looks like one of the laser diodes is failing.
Looking for a second opinion before I waste time or $$ on this older unit.
Thanx
491884918949190



:)

Genuine K/M Toner, Drum & Developer ?

When you had the dev unit out did you look at laser window to see if dirty?

If I think of anything else will post later

blackcat4866
05-20-2021, 12:15 AM
It certainly could be laser ... but I've never seen a bad KM laser unit, ever. Atypical of most of the laser issues I've addressed, it's usually not that subtle. =^..^=

tmmdmmm
05-20-2021, 01:57 AM
I've seen lasers fail, but never in a way that causes these IQ issues. Normally its mirror rotation/codes
You've pretty much hit all the spots, but have you tried cleaning the slit glass for the laser?

Toxic
05-20-2021, 08:17 AM
4e series have some problems with fine dust coming into laser unit and stick to poligon mirrors but in that case ussualy density should be lower on the paper far side.
If you already check everything else i would try to clean write unit.
You can read this topic about that.

C224e Print Quality Issues (Problem & Solution) (https://www.copytechnet.com/forums/konica-minolta/141107-c224e-print-quality-issues-problem-solution.html)

mojorolla
05-20-2021, 02:16 PM
Using all OEM and I physically removed / cleaned the laser, but I did not open it. The LD printouts are what caught my interest as the LD adjustment patterns description in the manual is "wood grain", which is what I am getting. Machine runs Stabilizer in image adjustments without issue.

Blackcat...never...? Now that is interesting.


:)

tsbservice
05-20-2021, 02:46 PM
I have 2 failed LSUs on C224e...but they failed with different symptom - many fine lines main scan direction. But yes can be LSU.

Toxic
05-20-2021, 06:06 PM
This is recently problem on C258, laser could cause different error patterns.
Top part of image is after laser cleaning and bottom is before cleaning.
My customer describe it like paper is needleworked :)

49201

tsbservice
05-20-2021, 06:17 PM
This is recently problem on C258, laser could cause different error patterns.
Top part of image is after laser cleaning and bottom is before cleaning.
My customer describe it like paper is needleworked :)

49201
Excellent work!

emujo2
05-20-2021, 08:22 PM
Even if it was a laser diode (which I highly doubt) you have to remember that each diode would be writing a line..If you had one not operating, or weak, you would see a greyscale checkerboard in your black areas..From my experience, the polygon mirrors do get dirty but tend to accumulate the dust on the edge of the mirrors, not the full length. I think you have another issue..I'm assuming the samples you posted are 1 from a good machine, one from you problem child and the 1/w tone from the same problem child. If a diode was bad, it would detect it during H-Sync. E

allan
05-20-2021, 10:36 PM
PH unit does look the similar. Does the part numbers for the C364e and C554e differ?

Does look like one of the diodes are not working correctly.

tsbservice
05-21-2021, 06:27 AM
PH unit does look the similar. Does the part numbers for the C364e and C554e differ?

Does look like one of the diodes are not working correctly.
They differ sure but actually it may work assumе he can try 2 beams type PH unit for C364e. There is some motor case on higher speed model to reduce the noise though.

Gift
05-21-2021, 07:13 AM
Hard to tell - is the grey page a large format print? Is it suppossed to be a solid black page?

One might get the impression there's an artifact repeating with the diameter of the drum, perhaps poor grounding/bad voltage. In case thelaser theory doesn't work out you might check that path.

We also had issues with the BK dev clutch every now and then (not shure if the mono xx4e has one) - that came with different CQ issue though..

Zesti
05-21-2021, 10:19 AM
Genuine K/M Toner, Drum & Developer ?

When you had the dev unit out did you look at laser window to see if dirty?

If I think of anything else will post later


Just to confirm LD, tweak laser settings in LD adjustment under Machine in Service mode.

mojorolla
05-21-2021, 08:11 PM
First off, thanks for all the replies. Let's see...

-yes ran all LD adjustments and tweaked output, got better or worse but no resolution

-printouts are all from troublesome unit. First 2 are from LD adjustment, last is a halftone pattern from test mode @ 125. I will look at the clutch, ty

-units are different, with the higher speed having an additional harness. I have 6 or the slower unit, just my luck

-the manual states this about the LD 1/2 balance adjustment: Each pattern has four squares. The two small squares diagonal to each other are printed with the same LD. (The pair of small squares where image density change corresponds to LD2.). The issues are the same in the diagonal blocks, which lead me to one of the LDs in the PH unit.

I haven't had a chance to get back to the shop but will try all suggestions early next week.


:)

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