Z5400 bad vertical lines--broken and offset

[D Hook]

I've just run into this problem with lines being offset on my Z5400 that I'm trying to repair.

I recently oiled the rear carriage rod and thought maybe I got some oil on the encoder strip. Cleaned the strip with just plain water, a dampened paper towel gently. No helpful results. This only happens on the vertical line. Horizontal lines are perfect. Also only happens on text and lines. Did an internal print of a photo and it came out fine.

This started when I had trouble with replacing one of the printheads. After replacing, the only prints I've done are the image diagnostic prints. This only print out blocks of color, no lines or text, and the test came out okay. Today I printed out an error log print and the border lines are broken and offset from each other. In the past, these tests have printed out fine, although the black was light due to a bad matte black/cyan printhead. Replaced yesterday.

I did have some trouble getting the printhead to work. Kept needing to be reseated. Not sure if I messed up something in the carriage on the ribbon cables or something. I cleaned the circuitry board that engages the back of the printhead with an HP cleaning kit. I reseated all three printheads and then did a printhead alignment, which didn't complete due to some banding on the magenta side of the yellow/magenta printhead. But that's been happening for a few days before this problem started so nothing abnormal about that. Up to this point it had been printing lines out just fine, though very light. (Need to buy a new magenta/yellow printhead. Printer has been sitting unplugged and unused for quite a while so expected some bad printheads.)

My question is; what else could I have done that might have created this sudden broken line/offset problem? Could I have damaged something else inside the printhead slot that would cause this problem? I did not try cleaning the encoder strip since I've gotten the printer. Only after this problem started today. Should I try using isopropyl alcohol on the strip for cleaning? Don't want to rub off the marks.

The belt looks brand new, no missing teeth, no tears or stretching evident. I've done several printhead alignments and also went into the service menu. Have not run a carriage test yet. Not sure it will test for this sort of problem.

Any advice/input would be most appreciated. I can post up a pic if that would help.

[D Hook]

Re: Z5400 bad vertical lines--broken and offset

Got it solved.

Part of the error message when testing the line sensor (which failed) said something about "the flag not reset" but I don't know what that meant. So I started over with the calibrations and read in the service manual about resetting the "flag" before doing a drop detector test. So I did reset the flag, which was on the same page as the drop detector test, then did the drop detector calibration, then did the line sensor calibration, which failed again but not for the flag reset. Then did another printhead alignment, which came out fine. When testing for the broken lines, they were no longer broken and the lines printed as they should. All the shadowing on the text is gone. Printed out usage reports, internal print of the GIS demo and all came out good.

So resetting the "flag" seems to be what fixed the problem. If anyone knows what the "flag" refers to, I'd be interested to know.

Thanks!

[Kiran Otter]

Re: Z5400 bad vertical lines--broken and offset

The drop detect 'flag' tells the printer not to perform a drop detection, for example when replacing it. You always have to clear the flag before calibrating the drop detector. This is detailed in the service manual.

My guess is this is so the new sensor doesn't get contaminated with ink by using the old calibration. But I find it hard to image that actually happening.

Kiran