Head Alignment and Paper Thickness
This may well be one of those "slap the forehead" moments, but I learned a valuable lesson this weekend I thought I'd pass along.
Things were chunking along beautifully with my Epson printer as I worked on the final production flow of my new chapbook series — at least for a while. This is the first time I've done more than simply experiment with the idea of two-sided printing, so I've been on a fast learning curve to get up to speed. One of the challenges is that by printing on roll paper it's absolutely mandatory to eliminate the curl before printing the backside. At Michael Reichmann's recommendation, I purchased a D-Roller and have found it to be a terrific tool. However, like every tool, improper use does introduce the possibility of pilot error. In my case, I found that I wasn't always aggressive enough and occasionally there would still be a bit of curl that became problematic. When printing the backside of the sheet, the head on the Epson printer would slightly clipped the edge of the paper — tick, tick, tick — a sound I've now learned to recognize with a cringe.
What I did not realize is that little bit of contact between the print head in the paper has the potential to throw the head alignment out of calibration. I started seeing some odd banding in the highlights, particularly noticeable in smooth skies. Easily enough remedied, I thought, because I've seen this before. I executed a head alignment and things got back to normal. And then, doggone it, tick, tick again — just twice and the head was out of alignment again. It made no sense to me that the head alignment could be thrown off so easily, so I decided to do some research. After scouring the Epson manual I came across one aspect of the head alignment process I had overlooked — paper thickness. Doh! Of course the thickness of the paper would affect the head alignment!
In my naïveté, I didn't realize the paper thickness in my printer was set 0.1 mm. The paper I'm using is actually 0.39 mm. I'm surprised the head could even align with this much difference, but it did. It also, however, appears to have been just on the edge of functionality and the tiniest little bump will get out of alignment. With this knowledge in hand, I did a corrected head alignment with the paper thickness measurement set properly and 0.4mm. Not only did the calibration correct the banding, but I find the prints ever so slightly sharper. Even more important, the occasional tick does not throw the head out of alignment. Now that I know, I'll pay more attention to that paper thickness business in the future.
It's the little things that always zap us.