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![]() Common Sense Maintenance For Solvent-Based Inkjet Printers
By Bob Flipse
Get a better understanding of the current trend toward spiraling sign permit fee costs.
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Would you place a solvent-soaked cloth on top of your car's finish? Do you drive your car 20,000 miles between oil changes and wait until it breaks, or do you change your oil at regular intervals? The good news is, maybe you can't perform the full preventive maintenance program your printer needs, but you can do your own "oil changes," or at least perform basic maintenance between major service intervals, often stretching that service interval out further. Like your car, your printer has critical fluid systems. In virtually any mechanical device, the fluid systems need to be kept clean for optimum life and performance. Your printer is no different. In fact, due to the volatility of solvents, ongoing maintenance is even more critical than for your car, for which most systems are sealed (e.g., your cooling system, oil, gasoline, etc.) In the case of your printer, there are printheads and caps/capping maintenance stations that are exposed to air when printing, and may be left exposed and in danger of drying out if there is a mechanical or electrical failure, or if poorly seated/sealed when in a resting position.
![]() Though each printer has its own maintenance routine, there are a number of things that apply to much any printer, regardless of manufacturer. Let's consider the technology and what is going on in the printer, working from the waste bottle back through the system.
Ink Maintenance Most of the printers mentioned have a pull-through pump system that draws ink through the printhead and helps prime it to keep ink flowing. In order to effectively draw ink through the printhead, there has to be a good seal between the cap and the printhead. Typically, the printhead has a flat surface, and the cap is essentially a rubber boot that seals the connection. If you don't have a good seal, air leaks may occur when the pump tries to pull ink through the printhead. When this happens, no ink will pull through the head, and it won't prime. In cleaning cycles, it won't clean either. Either one is bad news, of course. Several things can cause a cap/printhead seal issue:
Additionally, failure to keep the caps clean will result in faster degradation. Even when you finally clean with solvent and swabs, the crust becomes abrasive and tugs off bits of the cap in the process, resulting in premature failure. The solution is to take swabs and maintenance solution, and gently swab the caps - regularly. No matter how good you are at keeping the caps clean, there will still be an accumulation of pigment in the cap itself and down below. Use a recommended maintenance solution to wash the caps, sufficient in quantity to run right down to the waste bottle. This will thin the accumulation and help avoid the "clogging" of waste ink. Another crucial component of your ink system is the wiper/wiping station. On most printers, this is typically a rubber blade that wipes across the printheads periodically during printing. Using what you now know about your own ink system, what do you think will happen if you allow your wipers to be crusted with dry ink? The crust can be transferred to your printheads, and dried particles of ink pigments can be pressed into the orifices in your printheads - with disastrous results. Use the same care you do with your caps. No, these are not "seal" critical as are the caps, but less efficient wiping can have great effects on your print quality too.
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Best Practices If CMYK, do about four to six inches by 12 inches (15.25 x 30.5 centimeters) blocks of 100 percent of each color. If you have light cyan and magenta, make it six inches by eight inches (15.25 x 20.3 centimeters) blocks with the light colors being only 40 percent density, to assure that ink color is being used by the RIP. The same goes for orange, green or white ink. See below for an example. This will force your printer to use these colors even if you are not printing at the time. Scale according to the width of your printer and material. Some printers even have a thin "confidence stripe" that automatically prints on the edge of the graphic to assure that all colors are being used all the time. If your printer or RIP does not have this feature, create your own confidence stripe around a half-inch (12.7 millimeters) wide with all four to six colors, and run it the length of the graphic.
![]() Printing the full width bars as described above is a neat trick to help unclog otherwise serviceable printheads. When they come up, don't ignore the error messages and PM (preventive maintenance) flags on your printer. The manufacturers put them in for a reason, and like an oil change, they should not be ignored. If you aren't planning to use your printer for a while, longer than a month or more, you should have your system flushed. There are right and wrong ways to flush a printer. Additionally, there are specific storage fluids, which are not as volatile as maintenance solvents, so they won't dry out as quickly and your printer will be protected longer.
Manufacturer Inks There is a lot of physics and chemistry going on here - you have flow of ink from cartridges or tanks through ink lines, through dampers, which generally have filters in them, and then have to be jetted out of microscopic orifices at precisely the right size, moment and direction to get a clean print. If the ink dries too fast, it may coagulate on the printhead during printing, or overnight while the printer sits. The ink may not spread enough when it hits the vinyl, and you may see print banding. If the particle size is too large or irregular, your printheads may clog. If the ink dries too slowly, your prints may not dry before they wind up on your take-up system and they will be ruined. Even the temperature settings with the pre-, print-, and post-heaters come into play. This is not to say that there are not a number of good options for alternative inks out there. There are, but not all ink is created equal. A discussion on ink is an article all to itself.
Covering the Mechanics In addition to the moneymaking part of your printer, it's important to keep it looking good, as well as productive. Don't put solvent-soaked cloths, syringes, pipettes, bottles, or other maintenance items on your printer. If plastic, it will melt, and if paint, it may mottle the paint. If you splash ink on your printer, wipe it off quickly! Don't use a blade across the heater platen on your printer. No different than your car, no one wants a scratched up or scarred printer, even a used one. If you decide to sell it someday, it will be worth more when you have given it proper care. As we go out in the field, we see everything from the proverbial "you can eat off it" printer to some real ugly messes. Generally, the "proverbial ones" have better and more consistent results and longer intervals between major services. Though we recommend PM intervals of 12-18 months, we hear of some people going three to four years or more before service is required. Bottom line, if you take care of your printer, it will take care of you, and last longer as a result. Give yourself the best chance at success. Sometimes with even the best and most fastidious care, your printer will break down, just like your car. A 20-plus year industry veteran, Bob Flipse was an early innovator in wide-format digital printing. Starting in aqueous, his knowledge now covers solvent, UV and other ink technologies. Flipse is currently a partner at Grafx Network, a nationwide service company for wide-format printing equipment. bob@grafxnetwork.com This article appeared in the SGIA Journal, May/June 2012 Issue and is reprinted with permission. Copyright 2012 Specialty Graphic Imaging Association (www.sgia.org). All Rights Reserved.
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