Regardless of the wide-format printing technology used, output problems require a systematic approach that will save time, hassles, and tech calls. Here are some simple steps to help diagnose and fix the problem as quickly as possible.
Having fielded literally thousands of tech support calls for LexJet over the years it’s easy to see how little problems can become big problems rather quickly, particularly when there’s a big deadline to meet.
My goal during these types of emergency calls is to diagnose that problem as quickly as possible and get production moving again. By doing this countless times, I’ve developed a step-by-step troubleshooting system that’s been quite effective at identifying, diagnosing, and fixing the problem at hand.
In order to successfully eliminate the problem, you must identify it first, or at least find where it is in your workflow. While every issue is different, there are typically three main variables one can rule out to find the answer: image file, RIP, and printer. If you can confirm which one is the cause of the problem, then you can focus on finding a remedy without wasting time on what isn’t the cause of the problem.
Image File: File-related print issues are typically caused when a graphic designer applied settings to the file that either conflicted with the RIP or did not follow the rules of color management. It’s also possible that the file was corrupted while being saved or copied. The most common symptom of a file-related issue is a sudden color shift. One failsafe way to know that the file is the problem is if your whites are no longer white. For all printers a value of pure white means that no ink is being laid down, unless you’re using a UV-curable printer with a white ink channel. If your fluffy white clouds print pink, most likely the file is improperly color managed.
RIP: This can be anything related directly to the RIP, including inaccurate output profiles, incorrect color management settings, PostScript settings, and countless others. The most common symptom of a RIP-related issue (dealing with color) is improper use of output profiles. Output profiles (also referred to as printer profiles or media profiles) help the RIP translate the color data within the image file into accurate color output. If the output profile being used was not built for the exact printer, ink and media combination being used, then you may experience inaccurate and unpredictable color. While a given profile built for a different media may work, without an accurate profile built for the given media, you cannot guarantee accurate color.
Printer: Whenever the printer is not in an ideal state for printing, imperfect print quality will follow. The usual suspects are usually misaligned printheads or clogged nozzles. The most common symptom of a printer related issue is horizontal banding, which is usually caused by clogged nozzles. Clogged nozzles may also cause a color shift, and in some cases, you may see a color shift before you notice any banding. Printing a nozzle check pattern will help identify if you are currently missing any nozzles.
In most cases, you will find that the symptoms of the problem point to one of the three workflow components mentioned above. If this is the case, you should start by testing the suspect component. After testing is complete, you can verify or eliminate that component as a threat. If you verify the tested component as a threat, you can focus on finding a solution or workaround to the problem without wasting time on other non-related components.
If you have eliminated the tested component as a problem, you must now focus on testing one of the other two components to help identify the location of the problem. By systematically eliminating what the issue is not, you will eventually be faced with what the problem is.
Image File: If you suspect the image file is the cause of your problem, print a different file as a test image. This test image must be printed under the same conditions as the original image file in order to see if you get comparable results.
This test image must be one you have successfully printed before under the same conditions. It is also imperative that the test image has not been altered, converted or re-saved from its original state, as this may void the integrity of the test itself.
After printing the test image, compare it to the original image file. If the problems in the original image file appear in the test image, the problem is not in the image file, so you can eliminate it from the equation and look at your printer or RIP as one of the prime suspects.
RIP: This is the most difficult aspect of the print workflow to isolate and is usually the last item to be tested since ruling out the image file and printer first is much easier and can take much less time. Since color-related RIP issues were addressed above, we will focus on some of the RIP issues that are not color-related, which comes from PostScript files, like EPS and PDF files.
If the image file is an EPS or PDF, and fails to RIP, try RIPping a similar file type to see if the RIP is having trouble with other like file types. For example, if the image file you are trying to RIP is an EPS, and the RIP is crashing on that file, try to process another EPS test file you have successfully RIPped before to see if you get the same results. If the EPS test file does not rip successfully now, but has been successfully RIPped in the past, this indicates an issue with the RIP.
Printer: As stated earlier, the two most common printer-related issues are misaligned heads and clogged nozzles. Both of these issues can be diagnosed by printing specific test patterns. In most cases, these test patterns can be sent to the printer from the control panel of the printer itself, though these are sometimes executed from the printer’s driver or RIP.
Resolving the Issues
Image File: If the artwork was created in-house, then you can take the file back to the designer and discuss what is happening to the file and have them re-design the file accordingly. If the client has supplied the file, then it should be their responsibility to deliver a working file.
Since we all live and work in the real world, most of the time we have to deal with this problem on our own. If the image file is the problem, here are a few things you can try:
- Adjust color on the fly in the RIP, print a hard proof, and readjust as necessary
- Adjust the color in the file in an application like Photoshop or Illustrator, print a hard proof, and adjust accordingly
- Try printing the file using different input profiles and rendering intents
RIP: Own your color! Without using output profiles created for your media, you are limited to the accuracy of somebody else’s color that was made on somebody else’s printer. This is even worse if the output profile that you are using was not even built for the media that you are printing to. Even if these output profiles are good, without a spectrophotometer, like the X-Rite Eye One, you cannot linearize that profile to your printer. This can affect the accuracy of a profile, especially over time. If the RIP seems to fail when processing PostScript files, even ones that have RIPped successfully before, you may need to remove and reinstall the RIP. It is important that if you decide to remove and reinstall the RIP, that you back up all custom profiles as well as any other configurations to minimize the time it takes to reinstall.
Printer: If the nozzle check pattern shows clogged nozzles, run a cleaning cycle until all of your nozzles come back. If the printer uses thermal printheads, and the nozzles don’t recover, you may need to replace your printheads. Most printer operators have learned very quickly to print a nozzle check pattern when they see banding, but not always if there is a color shift.
If the Head Alignment target shows that heads are out of alignment, align the heads as necessary. The printer’s head alignment should be checked periodically. A head alignment is an adjustment used to maximize the accuracy of drop placement in both unidirectional and bidirectional print modes. This process typically involves printing out a target which shows different iterations of expected and actual drop placement. Next, the printer operator reads the target and enters in the values that represent the most accurate drop placement. Some of the newer model printers have the ability to automatically align themselves using optics located on the printhead carriage.
- If you have a color shift and don’t know where to begin, start with the nozzle check pattern for missing nozzles on your printer. It is the quickest to diagnose as well as a very common issue, especially with printers using piezo printheads.
- If you eliminate the printer as being the problem, and you still don’t know where to go, test the file by printing a test image.
- Head Alignment should be done periodically, but there are certain events where a head alignment is absolutely mandatory. These events include:
- When the printer is initially installed
- After the printer has been transported
- After a major head crash
- After replacing a printhead
- Do not stray from your findings. Don’t doubt something that has already been proven. For example, if the nozzle check pattern comes back perfect, don’t run a cleaning cycle. Instead, diagnose the other components of the print process.
As always, if you have any questions or need help fixing any problems in your workflow, contact a LexJet account specialist at 800-453-9538.