CLEANING THE PRINTERS

By Larry Bush

The Image printers may go through more makeup fluid than do the Videojets. Three and a half liters of makeup fluid were used to fill the receptacles on the Image printers this morning. Five could have been used.

When cleaning the Imaje printheads, sometimes the printheads have ink from the nozzles to the end of the head. The ink gets hard and dried on the printheads and is difficult to remove. Using a brush moves the tubular ink catcher/receivers out of position and this uses more cleaning fluid trying to get them lined up again.

The Imaje ink catchers are very small. It doesn't take much to cause the ink stream to miss the ink catcher completely or for the ink to hit the edge of the catcher. The ink then spatters all over the area and usually faults out the printer.

Sometimes cleaning takes very little fluid and sometimes more. When the ink is missing the catchers, more makeup fluid is used cleaning the Imaje printheads than the Videojet printheads. The catcher is so small that trying to get the ink stream into the catcher requires that the ink jets be turned on and off or adjusted while the jets are running.

The Imaje printers in use on the snack cup lines have four printheads with eight ink streams. The videojets have eight printheads with eight ink streams on the dual head printers.

The videojet printheads can be cleaned of some of the heavy concentrations of ink using a small tool to scrape the excess ink off the metal parts of the aperture plate on the printheads. Don't try to scrape the excess ink off the Imaje printheads due to their less robustness.

The high usage rates of Imaje makeup can be attributed to, mainly, the Imaje printers themselves. Maybe, the amounts being put into the printers and the amount used for cleaning printheads should be tracked by recording each container's destination.

Storing the liter containers of Imaje makeup fluid in the Printer Repair Room should solve the problem of not knowing where the fluid is stored. Makeup fluid and ink should be stored in the on site storage box at the printer station in order to have the fluids at the same temperature as the printer fluids during replenishment.

All 5 of the printers were out or very, very low when their makeup receptacles were replenished with new fluid. Technicians should check the printers for fluid levels each shift.

Ink levels should be replenished before the ink level reaches the point of an alarm status. Before the ink level alarms, the ink may become thicker resulting in a higher viscosity reading. A higher viscosity reading causes the pump speed to increase in order to maintain inline ink pressure and volume flow.

The higher viscosity also can cause ink blockage requiring that the printer be shut down and cleaned. With the viscosity between 32 and 36, the printer would require cleaning every ½ hour or ¾ hour.

From the time the ink viscosity was noted at 36 till the ink viscosity returned to 29 was around 6 hours. New ink was added to the printer immediately and it took 6 hours for the viscosity to level out at the normal reading. Nearly 5 hours was spent trying to keep the printer running during this time.

Do not store opened bottles of ink in the fluid storage box over the printers. Always empty the ink container into one or more printer ink receptacles. Always take the waste containers of used makeup and ink to the waste barrel and empty the waste container into the barrel.

Larry Bush

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About the Author: Larry Bush has been an electrician for 47 years, and in maintenance management for 22 years. Download his e-Book "Emergency Diesel Electric Generators" and the "Maintenance Policy and Procedures Manual" !!