HP CLJ 3550 CPR Sensor out of range - alignment issues

[KoenSP]

Hey,

after replacing the ETB unit in my color laserjet 3550 (by a genuine product) i started having problems with the alignment of my colors. At first only black seemed misplaced on the paper, I supposed the problem would have been resolved by replacing the toners, unfortunately it did not.  At this moment i replaced all toners by new ones (btw we only have used genuine toner in this device) and i still get the same alignement problems.

I performed several (more than a dozen) calibrations, i performed a cold start, i performed the "open front cover, hit machine reset for 3 seconds, close cover and inst. turn printer off/on" procedure - all this to remove the CPR data and to get the machine to reset his calibration.

I even reset the NVRam.  after this the alignement became worse !!

i even replaced the PS12 'color misregistration sensor' with a furbie from a CLJ3700 machine, reseated all the connectors, cleaned the sensorglass of the PS12.

i even tried the toners and etb of the clj3700 in the clj3550 machine. but the printed config page shows always the same miss alignement of the colors. (i can determine 2 groups - Cyan and yellow and magenta and black have a difference in the print of more than 3 mm.

btw also the latest firmware is installed.

what bothers me is that :

in the event log the errors '54.15.00 - 54.18.00 CPR Sensor out of range' occur

and even if we perform a calibration - the 'Last CPR Page count=37382' does not change - like he didn't do any calibration at all.

anybody any ideas?

what else can lead to a faulty alignement ? or what can prevent the calibration procedure from being executed correctly?

i would be a pity to discard this printer (all new toners, new etb, ...)

kind regards

koen

[davidzuts]

I have been working on printers for many years.  The one thing I have learned is when you change an item and start having issues, the first thing you need to look at is the item you replaced.  Since you replaced the transfer belt and since it is used during the calibration of the unit that is the first thing I would replace.  Just because it is a new item odds are it is very old stock since this printer is now very old and hp no longer makes the transfer belts for them.  I see you did try a belt from a 3700 so the only other thing I can suggest is the undocumented dc controller reset.  Instructions are at the link below:

https://www.laserquipt.com/support/idx/0/369/article/Color-Plane-Registration-Alignment.html

[KoenSP]

Thx for the suggestion 🙂

But as i described before : "i performed the "open front cover, hit machine reset for 3 seconds, close cover and inst. turn printer off/on" procedure - all this to remove the CPR data and to get the machine to reset his calibration.""

this is the procedure you mentioned in the link

i did not resolve anything.

apparently - off the print configuration page - the last CPR Page count always stays on 37382 and the Dmax/Dhalf count on 17680 despite the several calibration sessions, cold starts, init NVram, ...

if i compare to the 3700 this number (cpr page count) should follow +- the number of pages printed.

it's hard to know what the original number of pagecount for the 3550 was (after the nvram init) but it seems that this was +- 39393

so it appears that for +- 2000 copies he did not do a calibration - this could be the time that i changed the etb by a new one.

i have to mention : i bought a new genuine etb (sep 2015) but resend it because of simular problems, printed a while in black/white until the new etb  (dec 2015) arrived, what resulted in the same alignment issues.

now i tried with the etb of a working 3700 same problem. -> conclusion not etb related.

something else i observed; with the first etb change i had only one color deviating, after changing toners it became worse, and after the init NVram it was the worst deviation.  it would seem that he was living on old cpr data that was +- correct. after the init NVram the cpr data was cleaned and he returned to his worse state not capable of doing any calibrations at all.

something else is preventing a calibration session.

any ideas?

kind regards

koen

[KoenSP]

One more question :

comparing the 3700 results and the 3550.

for the 3700 the CPR count and the Dmax/DHalf count are equal (same amount).

for the 3550 the CPR count stands at 37382 and the Dmax/Dhalf count on 17680.

is this not presumed to be the same number? (done in the same calibration sessions)

another remark : after the init NVRam the cpr page count is not reset - so, in which memory does he store this page count number?

kind regards

[davidzuts]

Actually I did not read the link I gave you correctly.  What you need to do is turn off the printer.  Stick something in the engine test opening to press the button and turn on the printer.  Continue to hold until the printer initializes or comes to error.  If it starts to calibrate fine and if not turn the printer off and back on.  This procedure resets the dc controller.

[KoenSP]

hey,

performed the action you proposed : i  continuosly hold the "reset engine button" after turning the machine on, he just starts up, memorycount, initialize, calibrate and then prints the test engine page. (i dont 'see' a reset of the DC controller)

result : the calibration does not perform any changes in the print.

in the mean time i did everything again (other etb, other fuser, other toners, changed the ps12 sensor, nvraminit, disk initialize, ..) no solution.

all page counters are now at 0 (after the nvram init) except the last CPR Page count and dmax count, they remain unchanged ???

does he saves this information in the flash unit/eprom where the firmware is located? at the same place he holds the event log information, because even this is kept after the NVRam Init.

event log keeps stating 54.15.00 * 54.18.00 CPR sensor out of range.

getting desperate.