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  1. #1
    Senior Tech 100+ Posts mailderrick's Avatar
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    Color Matching on a Bixhub C450

    I want to put this out there to all the techs as i have theories and want some "fresh eyes"

    I bought a machine for a customer - rechipped CMY and the transfer ..(possible mistake) but wanted him to be happy and know that these drums are very capable of going a second cycle and they varied from 1/3 used - 1/2 used and almost 2/3 used.Transfer i don't recall anymore but prob around half (trying my best to remember)I did not rechip black and shows only a few bars used(unless someone previously rechipped that i do not know before i got it) However over all black looks good. Greyscale is a bit off not "grey" like it should be..

    They all still looked brand new

    Delivered the machine. Went back to do the set up and realized that the magenta started over toning. Cleaned the magenta IU and it worked...ohh..no only for a little while, then it started again. Replaced the magenta IU.
    Cyan looked Dark . replaced the cyan IU ..no change.
    Did gradation and image adjustments..everything still too dark or too blue...yellow is a lil strong also..played with densities along the way etc..everything slowly got even worse.

    reset the machine back to "0"....realized they have the fiery X3ETY IC402...had them load the drivers.. It did get a lil lighter but seems a bit yellow again when copying. and Cyan is still the wrong shade as well as magenta

    I need to go back, they are going to install the PS version of the IC402 tomorrow. I want to know if the trasnfer can play a roll in certain colors not matching. Magenta and Cyan IU's were changed but those 2 colors are still the worst. Darker shade of cyan/magenta and grainy when light density is printed.
    Am i missing something? Is it posible that even though the cartridges are black and look to be OEM they were possible aftermarket or recapped?
    Is there any knowledge out there of this printer printing dark or having trouble doing color matching.They want to use it for proofs and possible small flyer production runs.
    Is this machine not capable of producing an exact match when copying or printing. So far print and copy have been equal as far as the quality. Over all Quality looks good but def. wrong colors..esp in the greens,blues,some orange tones or anything dark becomes too dark.
    Ideas? dust? Change IDC transfer numbers? re do gradation adjustment? put in new toner..try tcr settings?
    There is a lot riding on me being able to bring this into at least a "normal range and spec"
    Please help....open to ideas!
    Derrick
    I have scans and samples if anyone wants to see this nonsense?


  2. #2
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    First things first.

    Resetting image units and transfer belts is fine in areas where colour matching is not a primary concern. If colour matching is a concern, use only OEM new, not rebuilt. This includes toner.

    It is likely that you are dealing with a machine that is a bit out of whack. But where is the key. Generally I recommend that you generate a test print from the copier itself via user menu. The test print here can tell you what the machine itself is doing. Though simplistic, it will only give you RGB and Process black gradation patterns, along with an assortment of colour blocks and an image along with text sample. The gradation patterns should all be relatively equal in density right down to 5%. They should be balanced based on the colour. So red should be the same shade of red through all densities. If it shifts yellow or magenta, that is unbalanced. Process black should look "black" through all gradations. Again, if one colour is dominant in the lighter gradations, you have an imbalance issue.

    Factors that can affect this are the transfer belt, transfer roller, image unit, LED unit or IDC sensors or HV unit. Image units should all be relatively the same age. The machine will usually compensate for age differences, but there is a limit to how much it can do this. Also, resetting the IUs or transfer belt will really affect how the machine registers colour reference to a new unit and will only amplify the limits if a worn unit is in the mix. Again, most office situations, this is not a problem. But if colour accuracy, specifically pantones, is of concern, use new whenever possible.

    This must be ensured before looking at the fiery.

    Second. The Fiery controller is an extension of the machine, but it can only do so much regarding colour accuracy of the machine on its own. It has to be periodically calibrated to what the machine is doing. Periodically is a subjective term. Calibrations can be done as often as the operator requires for colour accuracy. Daily fluctuations in weather can affect colour accuracy of the mainbody, so more often than not, print shops will calibrate their fiery daily, if not on a per job basis. Without doing a calibration, anything printed through the fiery will most certainly be affected and impossible to compensate, especially if the mainbody has not been serviced properly. Generally, I will look at a machine test page and compare it to the fiery test pattern. Much of the time, the gradations will speak for themselves where the problem lies, but without a calibration being done, you will only be chasing your tail.

    Third, the use of either PCL or PS is important in any job. Depending on the elements within the page, using either driver may or may not introduce the desired results. Sometimes colour may not be as expected, or a font doesn't work or the image looks distorted or off colour. I generally recommend that the user use either driver they want, but if the printout does not produce a desired result, use the other driver. If there is still a problem, call us for further assistance.

    Regardless of which driver is used, use ONLY the driver that is matched to the same version as the fiery is. Again, especially if the colour is an important aspect. Also the driver must have two way communications set for proper operation.

    There is much much more to how to deal with colour issues, but I think you should address the above items first before looking into the more advanced areas of colour accuracy. Otherwise, you will only be wasting time.

    "Many years ago I chased a woman for almost two years, only to discover that her tastes were exactly like mine: we both were crazy about girls."
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  3. #3
    Senior Tech 100+ Posts mailderrick's Avatar
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    Thank you for the reply. I am going to go there today and run gradations to see if anything looks to be off, clean and swap drums to see if there is any change. I am also not sure if i need to go into a menu and enable the fiery but besides all of that i think here is something out of whack. Last time i ran gradations from internally and i took them to a friend who used to be a Konica Tech and he told me hat they looked fine and everything was on point.But that can not be true. Here is 2 samples. Thorig_with_copy_b_overlay_d.jpgey are both from the same printed page from a HP 4550 that was copied, but i folded the copy and over laid one on the dark side and laid one on the copy_a.jpglight side of the color gradation and scanned so it is easy to see the colorp roblems. Even though this is copied using the ADF you will see what i orig_with_copy_b_overlay_l.jpgam up against as i am having the same basic problems when printing. The dark colors..esp Magenta and Cyan do not even look to be the correct shade. On the light gradation side,cyan and magenta are extra grainy. This page was after the intialization and on the black light gradation side somehow after the reset that light black looked less black than before the reset.I have the before page also which is copy a. I will up load that one also. I was just looking at the samplesnow as i was converting them from .pdf to .jpg to upload and on the light side on the scans all colors look to be grainy but from what i remember the yellow did not look as grainy and the black was more off black but anyway this seems to be very representitive over all.


  4. #4
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    Not to point out the obvious, but you started a thread in a Konica Minolta thread under the heading of a C450.

    The samples you are showing here are for an HP 4550, two completely different machines on so many levels, I do not know where to begin.

    This is the wrong forum for getting help on an HP, perhaps you should be looking in the HP forum over here.... HP

    "Many years ago I chased a woman for almost two years, only to discover that her tastes were exactly like mine: we both were crazy about girls."
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  5. #5
    Vulcan Inventor of Death 1,000+ Posts Mr Spock's Avatar
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    I believe he used the hp as a test chart but I could be wrong.
    First I would start by cleaning the optics and make sure they are spotless.
    Nest using a high grade paper run the stabilization and gradation until all numbers are below 75 (book and tech support will say below 100 is good).
    Then check a test pattern in each color from service mode. Any that are not good at 256, 128 and 75 settings I would replace that unit. If they are all not good then replace transfer belt unit. Then start these steps over.
    Once these come out good then try the test pattern again and see how good it is.

    And Star Trek was just a tv show...yeah right!

  6. #6
    Senior Tech 100+ Posts mailderrick's Avatar
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    I'm sorry. I wasn't as clear as I had hoped to be. The original came off of the hp 4550 printer next to their c450 copier. I then laid the original on the flatbed of the c450 to get copy a. Copy b is from after I intialized.all color image adjustment settings. Even though it was copies It is very representative of how the c450 is also printing off color in the same fashion


  7. #7
    Field Supervisor 500+ Posts copytechman's Avatar
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    Still, a hp 4550 is not a c450 especially with a fiery. Do you have a q13 kodak calibration chart? You need one to at least calibrate (most) fiery's on a basic level. I certainly wouldnt be comparing the 2 machines especially given the age of whatever consumables are in both machines.. they are very different beasts!

    Regards!
    A.


  8. #8
    Senior Tech 100+ Posts mailderrick's Avatar
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    Mr. Spock..you are correct!!!
    i was only showing how the konica (even when copying) is not even close to the right shade on cyan and magenta in particular and on the lighter densities when copying how it is grainy. I would never compare the 2 machines...but the copy of that sheet is a great representation of how the printing of that machine has been but since you can not see the monitor or know what the colors should look like it would be useless to send you a copy of the print, unless i can also get a copy of the original electronic file..which maybe i can!! will try.
    Also, i cleaned the hell out of the optics in that machine and also did the gradation in image adjustment (but i did not lay thre 10 blank pages on top like it says in the service manual) then a konica guy told me to initialize all color profiles and gradation settings as it throws colors off .....i can get a high grade paper and attempt it again..which ones would you run?
    and when you say run til all numbers are below 75...what if some are negative? and you mean all numbers.like highlight..etc...
    when i ran the yellow gradation page from internally it did jam entering the fuser each time...i had to leave and did not get to investigate that problem further. If yellow is my only current problem when he loads in the new drivers and prints then i will be very happy..but i doubt it given the fact the copy has always done about the same as the print and the cyan and magenta are very far off and those 2 units were just replace...i am thinking of dropping in a new toner and running the hell out of it til i can find out if it was a bunk toner refill or something but no idea how long it would take to run the toner through til ya actually get to the new one.
    Copytechman...no i do not have the q13 kodak calibration chart..at least i do not think so. i have one chart the konica tech gave me and i will have to pull it out to see which chart but as you can see from the samples the color is pretty far off from what it should be


  9. #9
    All things Konica Minolta 1,000+ Posts Stirton.M's Avatar
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    This is like comparing apples to oranges. The following is extremely dry (and lenthy) theory.

    The CCD optics of the C450 will likely never give you the same results as the original where colour and saturation are concerned.

    Mr Spock does outline clearly what is needed to get the C450 machine really close using multiple gradation adjustments, but you will run up against a brick wall where reproduction limitations of the CCD come into play, especially if the print engine of the copier is not up to snuff.

    As I mentioned before, the colour reproduction of the print engine itself is the baseline. If it is not balanced, then anything out of the Fiery will not be balanced. Gradation adjustments can help correct this, but there is a limit on how well this works, from one machine to another.

    As Mr Spoke pointed out, make sure the optics are clean. But that is not always enough.

    The optics of the copier adjusts itself to a white patch area. However, over time the white patch can become discoloured (CF900-911s had this problem in a big way) or the CCD itself will no longer have the same sensitivity to the light spectrum as it did new. Solid state devices do have limits on long term dependability. TV's for example....new, the colours are vibrant and strong and true. As the TV ages, they fade, become weak and shift. It is inevitable that they will eventually start to fail.

    The CCD on a C450 is no different in this regard. Nor the rest of the electronics for that matter. What it can do now compared to what it could do when brand new out of the box are two entirely different things.

    Now, technology limits in the CCD are also playing against you.

    The image you print from the HP, or any other toner based machine, likely will have a high DPI print. Many techniques to achieving this, not all do it the same. The toner for example, can be made up of symetrical shaped balls of plastic, or it is crushed plastic. The latter, there is no full control on definition due to uneven particle size. Or LED technology vs Laser technology. LED is to crayon as laser is to drafting pencil, the two are not exactly similar in definition. Some systems use multiple laser beams to increase dpi count.

    Depending on the technology used to print, the toner laid onto the page may take on an elongated appearance when viewed through a loop, relative to the feed direction. As the drum turns and has light shone upon it, the beam, laser or LED, will be on for a very short interval, but will still appear to be a streak, even if it is microscopic in length. A square pixel vs a rectangular pixel.

    The reproduced image, when scanned through a scanner unit, may or may not be accurately portrayed. The limits of the CCD, in this case, 600DPI cross direction, will vary the scan depending on how I placed the reproduced image on the glass. For example, I printed something on letter, long edge feed. The dots of toner will be elongated left to right as I look at the printed page. But they will still be 600DPI top to bottom. If I scan that same image on the glass, long edge on the left scale, it will have a very subtle difference to another scan of the same page, short edge on the left scale.

    Depending on the image, this may not be readily visible to the naked eye. Or it will be very obvious in other images, especially in solid colours. Moire is the effect. Here is a few examples of what I am speaking about. Pixel Magic - Moire Patterns

    But that is only part of the picture.

    Dot position is another, based on overall resolution. How the CCD may pick up those dots is of concern. The difference between 600DPI vs 1200DPI for example.

    Colour accuracy of the CCD itself will also be a factor. The original half tone may be red, but the CCD may not see it as red and inject more yellow or more magenta, or for that matter, black or cyan introduced. The dot position or length may influence this in unpredictable ways.

    Finally, pigments may not be reproduced accurately in some situations. For example, some ink pen writing, when scanned, may or may not produce the same colour your eyes see on the original. The reproduced may have strange rainbow effect. Again, depending on the printed image and how the toner was laid out through the print process, the CCD may see a yellow pixel in one spot, but not the magenta, so the net effect in red half tone reproduction, orange.

    Finally, depending on the mode you chose to scan can have a significant effect. Did you scan in text/photo mode? Or text mode only? Or Photo mode only? Or did you scan in map mode? Was the original glossy or matte? Was the paper high quality or generic. Was it bright white or standard?

    What you are trying to do, is reproduce prints from an HP on the KM using the scanner. And frankly, the variables to doing so successfully are acting against you. This is not to say it is impossible, but good luck keeping it that way over time. You will drive yourself nuts trying to adjust the two machines in a constant effort for perfect reproduction. Wear and tear, temperature, humidity, barometric pressure, electrostatic anomalies will all conspire against you over time.

    That said, if you were printing a page from both machines and wanted the printout from both to be close to identical in shades and hues and so forth, the best results would be to have both devices with their own fiery controllers, properly calibrated, the images printed through the fiery controllers, not "copied". Without the fiery, printing out the Konica Minolta Blue Ball logo will be noticeably different between the two machines, and likely neither will have the correct pantone. With the fiery, both will more than likely produce the same hue of blue. That is the value of a fiery controller.

    "Many years ago I chased a woman for almost two years, only to discover that her tastes were exactly like mine: we both were crazy about girls."
    ---Groucho Marx


    Please do not PM me for questions related to Konica Minolta hardware.
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  10. #10
    Field Supervisor 1,000+ Posts RRodgers's Avatar
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    All solid answers here. Looks like I'm not needed.

    Color is not 4 times harder... it's 65,000 times harder. They call it "TECH MODE" for a reason. I have manual's and firmware for ya, course... you are going to have to earn it.

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