C6501 Issues

[ginfay]

It definitely helped. I was able to get the registration very close (within +/-.5) on most stocks. I was just surprised that my local Konica techs didn't know anything about this. I spent a few hours and registered my most common paper stocks. It's not 100% accurate for all stocks, especially the heavier stocks, but I rarely run those duplex.

Thanks.

 

[grouimaging]

chart adjustment worked

chart adjustment worked

We got the instructions from KMGI sales also and they worked well. I posted a new thread with a link to the instructions from KMGI Sales if you want them along with his contact info.

My local KM tech did not know how to use the chart adjustment either. I think it is going to make my life a lot easier.

 

[Gene Glass]

KM6501 Calibration

KM6501 Calibration

Has anyone tried to use a program such as i1Share to objectively measure the 6501 Printer Gamma Offset Adjustment page? This measurement has always been a visual, and therefore "subjective" measuremenet.

Better still, does anyone have any tips/suggestions for matching two KM6501 machine calibrations? That is what I'm trying to accomplish.

If the Gamma Offset adjustement is close, does the Fiery Calibration and Profiling resolve any problems?

[email protected]

 

[UberTech]

Has anyone tried to use a program such as i1Share to objectively measure the 6501 Printer Gamma Offset Adjustment page? This measurement has always been a visual, and therefore "subjective" measuremenet.

Better still, does anyone have any tips/suggestions for matching two KM6501 machine calibrations? That is what I'm trying to accomplish.

If the Gamma Offset adjustement is close, does the Fiery Calibration and Profiling resolve any problems?

[email protected]

Technically two KM6501 should print closer than say a X700 and a KM6501. But in practice this is a bit harder to achieve because of several reasons...

Manufacturing inconsistencies
Transfer belt life
Developer life
Drum life
Environmental conditions of each machine
Toner batch
Etc etc

I’m not saying it is impossible to match machines, we can match a press output with adequate profiling but to get absolutely identical prints from two 'identical' machines is hard to achieve unless both have had identical counts and service cycle was the same.

But what is an identical print? This is subjective some would say they look similar and be happy others will get the loop out and count each pixel. I have a customer with 5501 with an IC-408 and a 6501 with an IC-303 initially they wanted identical prints as one machine did 80k a month and the other does 15k this was difficult to achive, also only one uses an eye-one to calibrate.

This ended up not being a problem as the prints were close enough for there customers.

The offset adjustment is subjective but I wouldn’t spend too much time on this. You should check them in D50 or daylight; personally I aim to have each offset just in between the two parallel lines. Unless they are radically out your not going to achieve to much and even if you did get it perfect (in your eyes) the next auto-gamma will change it again!

 

[lfelton]

Has anyone tried to use a program such as i1Share to objectively measure the 6501 Printer Gamma Offset Adjustment page? This measurement has always been a visual, and therefore "subjective" measuremenet.

Better still, does anyone have any tips/suggestions for matching two KM6501 machine calibrations? That is what I'm trying to accomplish.

If the Gamma Offset adjustement is close, does the Fiery Calibration and Profiling resolve any problems?

[email protected]

Now this is a *really* good question and highlights the one achilles heel of 6501s in a volume print environment where a reasonable degree of colour *consistency* and accuracy is required. We've not been able to resolve this problem, but are attempting to figure out something along the same lines as you, i.e. a "instrument" method of getting the Gamma adjust more accurate. The issue for us is matching reprints from month to month and it is a PITA and time consuming to match the colour. We also need to know in advance that the job is colour match critical and is a repeat job so that we can go pull the previous pass sheet, which is not easy when you are running many hundreds of jobs a month. We always re-do the gamma when the engineer leaves (some engineers are ok'ish at this and some are terrible) and that makes it more consistent, but nowhere near close enough that we can count on the colour consistency.

With the gamma done to the best of our ability (by eye), I can confirm that the Fiery Calibration and Profiling does not resolve this problem, but obviously it does reduce it.

Having said all that - I've seen similar issues with Indigos and most Xerox machines (a lot of Xerox machines are poor at colour consistency), so KM are not alone in this.

As mentioned, we're actively working on this problem, so are happy to swap results with you.

 

[UberTech]

Now this is a *really* good question and highlights the one achilles heel of 6501s in a volume print environment where a reasonable degree of colour *consistency* and accuracy is required. We've not been able to resolve this problem, but are attempting to figure out something along the same lines as you, i.e. a "instrument" method of getting the Gamma adjust more accurate. The issue for us is matching reprints from month to month and it is a PITA and time consuming to match the colour. We also need to know in advance that the job is colour match critical and is a repeat job so that we can go pull the previous pass sheet, which is not easy when you are running many hundreds of jobs a month. We always re-do the gamma when the engineer leaves (some engineers are ok'ish at this and some are terrible) and that makes it more consistent, but nowhere near close enough that we can count on the colour consistency.

With the gamma done to the best of our ability (by eye), I can confirm that the Fiery Calibration and Profiling does not resolve this problem, but obviously it does reduce it.

Having said all that - I've seen similar issues with Indigos and most Xerox machines (a lot of Xerox machines are poor at colour consistency), so KM are not alone in this.

As mentioned, we're actively working on this problem, so are happy to swap results with you.

I assume by gamma you mean gamma sensor calibration? This is the adjustment with the green arrow. The offset adjustment will not effect the consistency of long term printing rather your immediate opinion. Think long term vs short term memory.

I think Gene Glass is talking about consistency between two machines.

 

[Gene Glass]

KM6501 Gamma Offset

KM6501 Gamma Offset

Thanks to Ubertech and LFelton for your reply and ideas.

The Gamma Sensor adjust is the the multi-colored pattern page with the green arrow. After this adjustment, you fine-tune the Neutral Gray point using the Gamma Sensor Offset Adjustment procedure. This gives you the CMYK gradients on the left side of the page, and the Neutral Gray block on the lower right side.

In my case, we are trying to match two, brand new, identical systems (6501s with EFI Pro80 controllers).

My experience has been that the Gamma Sensor Offset Adjustment is critical to color printing accurach.

The KM manual states to adjust the CMYK values until you can barely see each value between the parallel gray guide bars. After roughing it in, you are supposed to compare the center square with the gray block created by black only (CMYK line with pink box). No matter how you do it, you received a different result each time you make the adjustement.

I wish there was a way to measure the correct values via a device such as the Xrite 1000. It would be nice if KM would publish what Lab or CMYK value the Gray box should be if properly adjusted.

 

[UberTech]

Thanks to Ubertech and LFelton for your reply and ideas.

The Gamma Sensor adjust is the the multi-colored pattern page with the green arrow. After this adjustment, you fine-tune the Neutral Gray point using the Gamma Sensor Offset Adjustment procedure. This gives you the CMYK gradients on the left side of the page, and the Neutral Gray block on the lower right side.

In my case, we are trying to match two, brand new, identical systems (6501s with EFI Pro80 controllers).

My experience has been that the Gamma Sensor Offset Adjustment is critical to color printing accurach.

The KM manual states to adjust the CMYK values until you can barely see each value between the parallel gray guide bars. After roughing it in, you are supposed to compare the center square with the gray block created by black only (CMYK line with pink box). No matter how you do it, you received a different result each time you make the adjustement.

I wish there was a way to measure the correct values via a device such as the Xrite 1000. It would be nice if KM would publish what Lab or CMYK value the Gray box should be if properly adjusted.

I guess you could measure the center square with eyeone share and aim for equal amounts of each colour but I think this needs to be subjective relative to the lighting in the enviroment. Again, you could get this perfect but it would change again after the next auto-gamma.

 

[lfelton]

@Gene - it's nice to chat about this issue with someone else who "gets it"! The following may be too simplistic, but IMO:-

1/ Gamma / grey balance set
2/ Profile media

should set a machine into a neutral "colour accurate" state

Following that a calibrate will return CLOSE to that state for minor machine fluctuations and thereafter:-

1/ Gamma / grey balance
2/ Calibrate

Should return the machine as close as it's going to get to the neutral "colour accurate" state, which in our experience is pretty close.



@Ubertech - IMO consistency between two machines is *exactly* the same issue as consistency from week to week. Both relate to the state of the machine's "wearing parts" (I'm sure there's a better way of explaining that, but you know what I mean) and the adjustments necessary to print consistent colour.

Also, I don't know what the auto "adjusting" process actually does, but I can assure you that it does not return the grey balance / neutral grey to an accurate state! I can also say that calibration alone (we calibrate at least twice a shift) cannot bring the colours back to a consistent level over time.

Take this morning; an operator ran the first sheet of a job for a regular customer. From experience he could tell that the colours were wrong. The sheet looked great, just wrong. The gamma/grey had been reset just over a week previously when some drums were replaced and when the operator printed out the test sheet, he could clearly see that the magenta was too high and the cyan was a little low. The grey was set again, the machine calibrated again and the first sheet of the customer's job was printed again. The colours were significantly different and "right", based on comparisons with a previously printed job and the job viewed on a calibrated monitor. So, the auto adjust is manifestly not returning the gamma / grey balance to a "good" state, in fact it doesn't seem to do anything to it (the grey balance) at all.

Now that example is on a high clicking 6501 doing well over 150,000 SRA3s a month (and producing a lot of excellent quality work), but IMO KM really need to get their thinking caps on and put together a set of guidelines for commercial customers. I'm not talking about hardware changes, that will come with the next generation machines, which hopefully should come equipped with a KM version of ACQS. More like a set of guidelines, i.e. machines within the Q zone should have a gamma/grey balance adjust done every "n" thousand clicks, calibrate every "n" hundred clicks (machines outside of the Q zone are SOL), etc. etc.

Make sense?

 

[grouimaging]

Is the gamma offset adjustment an option only on the Fiery Rip? We have two 6501's with Creo.

 

[lfelton]

No, it's a machine adjustment. Your engineer will do it after changing components, but you learn how to do it yourself in the advanced operator course.

 

[Emgee]

No, it's a machine adjustment. Your engineer will do it after changing components, but you learn how to do it yourself in the advanced operator course.

@lfelton (or anyone else who knows)...

Would anyone be willing to post the steps on how to do the gamma offset adjustment?

Thanks!

 

[UberTech]

Is the gamma offset adjustment an option only on the Fiery Rip? We have two 6501's with Creo.

All gamma adjustments are available in the expert adjustment mode, planted deep to keep out the cowboys I suspect.

The offset adjustment was (and is) available as an auto-adjusment, so print off the offset place on glass. This adjustment should be avoided as I think it is tuned for paper they use in the factory (j-paper?) and renders a poor result if you use normal paper. Nice to know they are heading that way tho.

The auto-gamma that you are refering to does not try to balance grey rather adjust for density. This is the density on the belt NOT your paper. This is what the offset adjustment is for as obviously this will different depending on what paper you have.

If you intend to do this off your own bat you need to...

1. Do an auto-gamma
2. Do a gamma sensor calibration (reset all screens first).
3. Do another auto-gamma
4. THEN do an offset adjustment .
5. Then calibrate your rip.

It's not a case of doing an auto-gamma doing the offsets and hope for a good result.

They are easy buttons to push but you need to push them in the right order.

You would only be doing this if you were a bit of perfectionist as it shouldn't need doing between service i.e the calibration should account for any discrepancies.

 

[grouimaging]

I was also having skew and reg issues until

I was also having skew and reg issues until

I was having skew and registration issues on my KM 6501 and was looking for a different machine as a second printer when I found from a KM sales guy on this forum a solution that works so well that I bought my second KM6501. here is the link: http://proofs.groupimaging.com/gi/KonicaMinolta/C6500PaperAdjustmentProcedure.doc

It is alot easier to do than the two pages of directions make it out to be. I would buy two things first: 1. a 12" digital caliper that measures in both inches and mm $119.00 at Rutland Tool - Loading... and a light box so you can see through your paper to do the chart adjustment. Just set this up when you change types of papers and it will make your life easier. I have three employees who are tained on this now. fyi, you might have had time getting your KM tech to help you with this as it appears they are not aware of how to do it. I have taught two of them how to do it also. Works well.

Call me if you have any questions: Jeff Burris 602-989-0221 cell

 

[bsiderys]

The registration issue is frequently seen in most placements that run card stock. If the machine doesn't run the 300g from the main trays and has little in the way of solid constuction in the trays,....how can it be expected to run good registration. Any one who is looking a machine to run card stock consistantly should look to a machine that handles the stock in all areas...and trays. The price point and the specs (which don't sound like they are making it) have won a lot of placments.

 

[bsiderys]

Wow that seems like a lot of work to get the registration to work. Did the sales rep show this to you before you bought the machine? Would you have purhcased the Konica if you had known this problem?

 

[UberTech]

The registration issue is frequently seen in most placements that run card stock. If the machine doesn't run the 300g from the main trays and has little in the way of solid constuction in the trays,....how can it be expected to run good registration. Any one who is looking a machine to run card stock consistantly should look to a machine that handles the stock in all areas...and trays. The price point and the specs (which don't sound like they are making it) have won a lot of placments.

Tell me about the trays in c6501. Im really interested to hear.

 

[aqa-man]

card registration good

card registration good

Running (silk art) 300 (350g) from the main large capacity decks is good on 6501; must set it up properly, using the proper single-sheet set-up and centering. We do it all the time, loads of d/sided jobs.

 

[graymatter]

First, be sure you set the media correctly. Not just weight, but GL/ML/GO/MO. Don't cheat.

If it's FTB that's a problem, there's a paper setting button that allows the operator to adjust this for each media.

Face it. Stock that's been through the fuser once is not the same piece that it was out of the wrapper. Not electrically, mechanically or anything. Use the paper setting to dial in so every time you run that stock you're good to go. That's why the settings are there.

Too many ops want to just drop a stock in - any stock - and expect them all to run the same way. This isn't an office copier and PSOs aren't secretaries. KM gave you all these great adjustments to front/back scaling, image shift, registration arch, etc. USE THEM.

 

[graymatter]

The registration issue is frequently seen in most placements that run card stock. If the machine doesn't run the 300g from the main trays and has little in the way of solid constuction in the trays,....how can it be expected to run good registration. Any one who is looking a machine to run card stock consistantly should look to a machine that handles the stock in all areas...and trays. The price point and the specs (which don't sound like they are making it) have won a lot of placments.

Trays have far less to do with registration than you seem to think, except maybe for how the machine handles static as it pulls the sheet, esp. on glossy stocks. Arch and registration timing are where it all happens... or doesn't. Just because a machine handles 300gsm stock in all trays doesn't mean it's automatically going to have more accurate registration.