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Author Topic: Epson SC-P7500 and avoiding nozzle clogs  (Read 447 times)

Jeremy Roussak

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Epson SC-P7500 and avoiding nozzle clogs
« on: November 19, 2020, 02:03:48 pm »

Maybe someone will find this useful, or at least amusing. It doesn't compare with the angst that Peter describes in his thread, but it reinforces the benefits of user groups and worldwide cooperation.

I recently became the proud, if somewhat poorer, owner of an Epson SC-P7500 (7570 in the US, I think). I don't print every day, or even every week, so of course I started to worry about blocked nozzles. I derived some reassurance from living in Manchester, which is, to put it mildly, generally neither hot nor dry, but I'd read sufficient horror stories still to be concerned. So I wanted to set up my iMac (which is always on) to print something from time to time, unattended. I bought a roll of plain paper, which was very cheap.

It seemed to me that a nozzle check pattern would be a good thing to print. It uses all the nozzles, including both PK and MK lines, with very little ink and not much paper wastage. I set up a Keyboard Maestro macro that opened System preferences' Printers and Scanners tab, clicked on the printer in the list, clicked on "Utility" and "Print test page", then "OK" and "close window". It worked very nicely (it's quite fun to watch, the whole thing taking less than a second) and KM allows me to set it to run automatically at a particular time on selected days of the week.

Unfortunately, it didn't work when the screen was locked, requiring a password. I have lots of client-confidential stuff stored on the Mac, so it has to be password-protected, particularly when I'm away (the Information Commissioner can fine me £5k for each data breach if anything is hacked, which could work out a bit on the pricey side for several thousand of pieces of information). A solution which only worked when I was at my Mac wasn't really much help.

I asked around the KM help forums. There's no way for KM to be able to unlock the Mac, as UI control is disabled at the login screen[1]. It can, however, print a file even if the screen is locked, and someone showed me how. So I could print an image, but it used a lot of paper and a lot of ink and only one of the PK/MK channels.

It occurred to me that the System preferences panel probably sent a single command saying "print a test page". Given the idea by someone on the Epson Large Format Google group (a very helpful bunch, as are the KM people), I found and dug around in the spool folder on the Mac just after I'd printed a test page, and sure enough there was a small text file, whose contents were


This looked very promising. I copied it to my desktop and set up the KM macro to execute a shell script:

     lpr -P Photo_24_ /Users/jbr/Desktop/printTestPage.txt

and it works just fine. Out comes a nozzle check, which I've set to happen four times a week.

Is it necessary? I don't know what it does for the printer[2], but it's worked wonders for my neuroticism; and the journey has demonstrated to me, yet again, what a wonderful resource help forums can be and how much, perversely, I enjoy playing with stuff like this when I should be doing something useful.

Of course, I have to remember to load the plain paper roll before I go away. If only I could automate that. And, indeed, since our re-established lockdown, if only I could go away.


[1] subsequently I've been told that KM can unlock a Mac by running an AppleScript. I've not tried it, as I don't want my iMac to be unlocked when I'm away.
[2] Mark Segal tells me, not much

PS: me and my toy.
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