KM C300 Yellow print looks more like mustard color

[Solotime]

Hello Guys,
Went out look at this machine today because the customer said the colors were off. Everything seems fine except that the yellow prints, and the yellow that is printed on the Color Demo page straight from the copier has a mustard or a bit of greenish tint to the yellow. The yellow bars that are printed on the Color Gradation charts look perfect. But the yellow blocks and the circle that is printed in yellow on the color test print as well as the yellow that prints from the customer PC are off a bit. Is there a color balance adjustment I am missing? Again since the yellow prints fine by itself it seems to be something the copier is doing to "change" the yellow prints slightly. For example if I run a single color yellow copy it is fine. It is just when something is either printed from the ops panel or from the customers PC.
Thanks in advance!

[Solotime]

Re: KM C300 Yellow print looks more like mustard color

Can not see where it would make a difference as the yellow copy and the yellow color bars on the gradation chart are perfect yellow BUT...the yellow imaging unit was swapped with another C300 in this office by another tech who was troubleshooting a squeak. Only the yellow I/U was swapped.
Any thoughts?

[minimerlin]

Re: KM C300 Yellow print looks more like mustard color

Can not see where it would make a difference as the yellow copy and the yellow color bars on the gradation chart are perfect yellow BUT...the yellow imaging unit was swapped with another C300 in this office by another tech who was troubleshooting a squeak. Only the yellow I/U was swapped.
Any thoughts?

Have you done a reset and stabilization followed by grad adjust?

[Solotime]

Re: KM C300 Yellow print looks more like mustard color

Of you mean the Initialize + Image Stabilization then no I have not

[EarthKmTech]

Re: KM C300 Yellow print looks more like mustard color

epic fail


initialise and then a gradation adjust is the first thing you should of done - AFter vacuuming all the stray toner out of the machine. including making sure the lasers are surgically clean along with the idc sensors. If your a half ass tech, you'll just do the adjustment after nothing else and walk away.

IU condition should also be checked and they should be perfect before doing this too.

[EarthKmTech]

Re: KM C300 Yellow print looks more like mustard color

Also, I forgot to mention, its a good habit to get into with these filthy old machines (C250 - C352) to clean the ozone filter on every call. It gets blocked up with toner and once that happens destruction of the imaging units will occur even more rapidly.

[Solotime]

Re: KM C300 Yellow print looks more like mustard color

I had already cleaned lasers and sensors. Performed the initialize and gradation with no change. Here is a pic of the Gradation Chart and the test print page where you can see the difference in the yellow colors.
C300test.jpg

[EarthKmTech]

Re: KM C300 Yellow print looks more like mustard color

I would try doing the gradation adjustment using a known standard, high quality paper, not general crappy office paper, if its running the latest firmware 2 prints and scans per mode, initial release firmware requires 3 prints and scans per mode. Put at least 3 blank sheets on top of the page when scanning it too.

If its still printing mustard yellows there may be a hardware issue. I am under the assumption that the toner is genuine, all the imaging units are perfect, not reset lifes and the transfer belt is the same.

[EarthKmTech]

Re: KM C300 Yellow print looks more like mustard color

also note, that when printing from a PC on this model, using the PS driver gives a wildly different yellow to the PCL driver. Choose your driver appropriately to what they desire.

[Hansoon]

Re: KM C300 Yellow print looks more like mustard color

I've seen similar when using after market toner..........

Hans

[Solotime]

Re: KM C300 Yellow print looks more like mustard color

Made sure all the suggestions have been done. All cleaning has been done as well as Initialization and at least 3 Gradation Adjustments with no change. Toner I am sure is OEM but even if not, I can not figure why the yellow bands on the Gradation Chart are perfect yellow but the internal Demo Print Page the yellow is off. For some reason it seems as tho the yellow coming from the IU is fine but when actually printing a page from the PC or from copier internally the yellow is slightly off shade.
We have 2 C352 machines coming in this week so I may just try some swapping next.