I was chilling with a hot cup of coffee when the call came: “KC, my dots are not matrixing! They’re all over the place and the inkjet code is a mess. Get over here pronto.”

My first reaction was to have them reset the system or call the vendor but that only works when the problem is consistent and theirs wasn’t. Mostly it was fine but would then go haywire for a bit.

Intermittent problems are hardest because they never seem to happen when you’re looking. They look random but seldom are. It requires some serious cogitation to figure out what’s going on.

When I got eyeballs on the system it was printing a nice legible code. First appearances can be deceiving and I knew that if I watched long enough I would see something interesting.

Sure enough, after about 20 minutes, we got a series of about 50 bottles in a row with illegible printing. After that, normal.

“Fiddlesticks on printer problems,” I told the superintendent. “The printer is fine but it’s next to the warehouse door. Each time the door opens, the air curtain blows on the printhead. As the ink droplets cross the gap between printhead and bottle, the air knocks them silly. When the curtain stops, the droplets fly normally. This may be a hard problem to troubleshoot but an easy one to fix. A baffle around the printhead will prevent the air from blowing on it.”

Now, back to that coffee…

KC Boxbottom, packaging detective, is on the case to solve tough packaging puzzles. He is the alter-ego of John Henry, CPP. Known as the Changeover Wizard, Henry is the owner of Changeover.com, a consulting firm that helps companies find and fix the causes of inefficiencies in their packaging operations. He produces a free monthly newsletter called Lean Changeover, which contains articles and tips on changeover and related issues. Reach him at [email protected].